Initial commit

10 files changed, 3114 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..f258c23
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,9 @@
+# Build files
+/build
+
+# Qt Creator files
+/CMakeLists.txt.user*
+/liberty.config
+/liberty.files
+/liberty.creator*
+/liberty.includes
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..6886373
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,18 @@
+language: c
+notifications:
+ irc:
+  channels: "anathema.us.nu#anathema"
+  use_notice: true
+  skip_join: true
+compiler:
+ - clang
+ - gcc
+before_install:
+ - sudo apt-get update -qq
+before_script:
+ - mkdir build
+ - cd build
+script:
+ - cmake .. -DCMAKE_INSTALL_PREFIX=/usr
+ - make
+ - ctest -V
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..75ef930
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,34 @@
+project (liberty C)
+cmake_minimum_required (VERSION 2.8.5)
+
+# Moar warnings
+if ("${CMAKE_C_COMPILER_ID}" MATCHES "GNU" OR CMAKE_COMPILER_IS_GNUC)
+	# -Wunused-function is pretty annoying here, as everything is static
+	set (CMAKE_C_FLAGS "-std=c99 -Wall -Wextra -Wno-unused-function")
+endif ("${CMAKE_C_COMPILER_ID}" MATCHES "GNU" OR CMAKE_COMPILER_IS_GNUC)
+
+# Dependencies
+find_package (PkgConfig REQUIRED)
+pkg_check_modules (libssl REQUIRED libssl libcrypto)
+
+# -lpthread is only there for debugging (gdb & errno)
+# -lrt is only for glibc < 2.17
+set (common_libraries ${libssl_LIBRARIES} rt pthread)
+include_directories (${libssl_INCLUDE_DIRS})
+link_directories (${libssl_LIBRARY_DIRS})
+
+# Generate a configuration file
+# TODO: actualy use the configuration file for something; so far we allow
+#   for direct inclusion without running this CMakeLists.txt
+configure_file (${PROJECT_SOURCE_DIR}/liberty-config.h.in
+	${PROJECT_BINARY_DIR}/liberty-config.h)
+include_directories (${PROJECT_SOURCE_DIR} ${PROJECT_BINARY_DIR})
+set (common_sources ${PROJECT_BINARY_DIR}/liberty-config.h)
+
+# Build some unit tests
+enable_testing ()
+foreach (name liberty)
+	add_executable (test-${name} tests/${name}.c ${common_sources})
+	target_link_libraries (test-${name} ${common_libraries})
+	add_test (test-${name} test-${name})
+endforeach (name)
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..43a2aa3
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,14 @@
+ Copyright (c) 2014 - 2015, Přemysl Janouch <p.janouch@gmail.com>
+ All rights reserved.
+
+ Permission to use, copy, modify, and/or distribute this software for any
+ purpose with or without fee is hereby granted, provided that the above
+ copyright notice and this permission notice appear in all copies.
+
+ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/README b/README
new file mode 100644
index 0000000..7d20085
--- /dev/null
+++ b/README
@@ -0,0 +1,20 @@
+liberty
+=======
+
+`liberty' is a pseudolibrary of all the common C code I have written for various
+projects.  It can be thought of as a successor to my other C library, libxtnd.
+
+You are supposed to import it as a git submodule and include the main source
+file directly everywhere you need it.  Everything is declared "static".  I have
+come to the conclusion that this style of C programming suits me the best, as it
+allows me to nearly forget about the mess that are header files.
+
+License
+-------
+`liberty' is written by Přemysl Janouch <p.janouch@gmail.com>.
+
+You may use the software under the terms of the ISC license, the text of which
+is included within the package, or, at your option, you may relicense the work
+under the MIT or the Modified BSD License, as listed at the following site:
+
+http://www.gnu.org/licenses/license-list.html
diff --git a/liberty-config.h.in b/liberty-config.h.in
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/liberty-config.h.in
diff --git a/liberty.c b/liberty.c
new file mode 100644
index 0000000..7c7c16e
--- /dev/null
+++ b/liberty.c
@@ -0,0 +1,2577 @@
+/*
+ * liberty.c: the ultimate C unlibrary
+ *
+ * Copyright (c) 2014 - 2015, Přemysl Janouch <p.janouch@gmail.com>
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#define _POSIX_C_SOURCE 199309L
+#define _XOPEN_SOURCE 600
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <ctype.h>
+#include <time.h>
+#include <limits.h>
+
+#include <unistd.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <signal.h>
+#include <strings.h>
+#include <regex.h>
+#include <libgen.h>
+#include <syslog.h>
+#include <fnmatch.h>
+#include <iconv.h>
+
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <netdb.h>
+
+#ifndef NI_MAXHOST
+#define NI_MAXHOST 1025
+#endif // ! NI_MAXHOST
+
+#ifndef NI_MAXSERV
+#define NI_MAXSERV 32
+#endif // ! NI_MAXSERV
+
+#ifdef LIBERTY_WANT_SSL
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+#endif // LIBERTY_WANT_SSL
+
+#include <getopt.h>
+#include "siphash.c"
+
+extern char **environ;
+
+#ifdef _POSIX_MONOTONIC_CLOCK
+#define CLOCK_BEST CLOCK_MONOTONIC
+#else // ! _POSIX_MONOTIC_CLOCK
+#define CLOCK_BEST CLOCK_REALTIME
+#endif // ! _POSIX_MONOTONIC_CLOCK
+
+#if defined __GNUC__
+#define ATTRIBUTE_PRINTF(x, y) __attribute__ ((format (printf, x, y)))
+#else // ! __GNUC__
+#define ATTRIBUTE_PRINTF(x, y)
+#endif // ! __GNUC__
+
+#if defined __GNUC__ && __GNUC__ >= 4
+#define ATTRIBUTE_SENTINEL __attribute__ ((sentinel))
+#else // ! __GNUC__ || __GNUC__ < 4
+#define ATTRIBUTE_SENTINEL
+#endif // ! __GNUC__ || __GNUC__ < 4
+
+#define N_ELEMENTS(a) (sizeof (a) / sizeof ((a)[0]))
+
+#define BLOCK_START  do {
+#define BLOCK_END    } while (0)
+
+#define MIN(a, b)  ((a) < (b) ? (a) : (b))
+#define MAX(a, b)  ((a) > (b) ? (a) : (b))
+
+#define STRINGIFY(x) #x
+#define XSTRINGIFY(x) STRINGIFY (x)
+
+// --- Logging -----------------------------------------------------------------
+
+static void
+log_message_stdio (void *user_data, const char *quote, const char *fmt,
+	va_list ap)
+{
+	(void) user_data;
+	FILE *stream = stderr;
+
+	fputs (quote, stream);
+	vfprintf (stream, fmt, ap);
+	fputs ("\n", stream);
+}
+
+static void (*g_log_message_real) (void *, const char *, const char *, va_list)
+	= log_message_stdio;
+
+static void
+log_message (void *user_data, const char *quote, const char *fmt, ...)
+	ATTRIBUTE_PRINTF (3, 4);
+
+static void
+log_message (void *user_data, const char *quote, const char *fmt, ...)
+{
+	va_list ap;
+	va_start (ap, fmt);
+	g_log_message_real (user_data, quote, fmt, ap);
+	va_end (ap);
+}
+
+// `fatal' is reserved for unexpected failures that would harm further operation
+
+#ifndef print_fatal_data
+#define print_fatal_data    NULL
+#endif
+
+#ifndef print_error_data
+#define print_error_data    NULL
+#endif
+
+#ifndef print_warning_data
+#define print_warning_data  NULL
+#endif
+
+#ifndef print_status_data
+#define print_status_data   NULL
+#endif
+
+#define print_fatal(...) \
+	log_message (print_fatal_data,   "fatal: ",   __VA_ARGS__)
+#define print_error(...) \
+	log_message (print_error_data,   "error: ",   __VA_ARGS__)
+#define print_warning(...) \
+	log_message (print_warning_data, "warning: ", __VA_ARGS__)
+#define print_status(...) \
+	log_message (print_status_data,  "-- ",       __VA_ARGS__)
+
+#define exit_fatal(...)                                                        \
+	BLOCK_START                                                                \
+		print_fatal (__VA_ARGS__);                                             \
+		exit (EXIT_FAILURE);                                                   \
+	BLOCK_END
+
+// --- Debugging and assertions ------------------------------------------------
+
+// We should check everything that may possibly fail with at least a soft
+// assertion, so that any causes for problems don't slip us by silently.
+//
+// `g_soft_asserts_are_deadly' may be useful while running inside a debugger.
+
+static bool g_debug_mode;               ///< Debug messages are printed
+static bool g_soft_asserts_are_deadly;  ///< soft_assert() aborts as well
+
+#ifndef print_debug_data
+#define print_debug_data   NULL
+#endif
+
+#define print_debug(...)                                                       \
+	BLOCK_START                                                                \
+		if (g_debug_mode)                                                      \
+			log_message (print_debug_data, "debug: ", __VA_ARGS__);            \
+	BLOCK_END
+
+static void
+assertion_failure_handler (bool is_fatal, const char *file, int line,
+	const char *function, const char *condition)
+{
+	if (is_fatal)
+	{
+		print_fatal ("assertion failed [%s:%d in function %s]: %s",
+			file, line, function, condition);
+		abort ();
+	}
+	else
+		print_debug ("assertion failed [%s:%d in function %s]: %s",
+			file, line, function, condition);
+}
+
+#define soft_assert(condition)                                                 \
+	((condition) ? true :                                                      \
+		(assertion_failure_handler (g_soft_asserts_are_deadly,                 \
+		__FILE__, __LINE__, __func__, #condition), false))
+
+#define hard_assert(condition)                                                 \
+	((condition) ? (void) 0 :                                                  \
+		assertion_failure_handler (true,                                       \
+		__FILE__, __LINE__, __func__, #condition))
+
+// --- Safe memory management --------------------------------------------------
+
+// When a memory allocation fails and we need the memory, we're usually pretty
+// much fucked.  Use the non-prefixed versions when there's a legitimate
+// worry that an unrealistic amount of memory may be requested for allocation.
+
+// XXX: it's not a good idea to use print_message() as it may want to allocate
+//   further memory for printf() and the output streams.  That may fail.
+
+static void *
+xmalloc (size_t n)
+{
+	void *p = malloc (n);
+	if (!p)
+		exit_fatal ("malloc: %s", strerror (errno));
+	return p;
+}
+
+static void *
+xcalloc (size_t n, size_t m)
+{
+	void *p = calloc (n, m);
+	if (!p && n && m)
+		exit_fatal ("calloc: %s", strerror (errno));
+	return p;
+}
+
+static void *
+xrealloc (void *o, size_t n)
+{
+	void *p = realloc (o, n);
+	if (!p && n)
+		exit_fatal ("realloc: %s", strerror (errno));
+	return p;
+}
+
+static void *
+xreallocarray (void *o, size_t n, size_t m)
+{
+	if (m && n > SIZE_MAX / m)
+	{
+		errno = ENOMEM;
+		exit_fatal ("reallocarray: %s", strerror (errno));
+	}
+	return xrealloc (o, n * m);
+}
+
+static char *
+xstrdup (const char *s)
+{
+	return strcpy (xmalloc (strlen (s) + 1), s);
+}
+
+static char *
+xstrndup (const char *s, size_t n)
+{
+	size_t size = strlen (s);
+	if (n > size)
+		n = size;
+
+	char *copy = xmalloc (n + 1);
+	memcpy (copy, s, n);
+	copy[n] = '\0';
+	return copy;
+}
+
+// --- Double-linked list helpers ----------------------------------------------
+
+#define LIST_HEADER(type)                                                      \
+	type *next;                                                         \
+	type *prev;
+
+#define LIST_PREPEND(head, link)                                               \
+	BLOCK_START                                                                \
+		(link)->prev = NULL;                                                   \
+		(link)->next = (head);                                                 \
+		if ((link)->next)                                                      \
+			(link)->next->prev = (link);                                       \
+		(head) = (link);                                                       \
+	BLOCK_END
+
+#define LIST_UNLINK(head, link)                                                \
+	BLOCK_START                                                                \
+		if ((link)->prev)                                                      \
+			(link)->prev->next = (link)->next;                                 \
+		else                                                                   \
+			(head) = (link)->next;                                             \
+		if ((link)->next)                                                      \
+			(link)->next->prev = (link)->prev;                                 \
+	BLOCK_END
+
+#define LIST_APPEND_WITH_TAIL(head, tail, link)                                \
+	BLOCK_START                                                                \
+		(link)->prev = (tail);                                                 \
+		(link)->next = NULL;                                                   \
+		if ((link)->prev)                                                      \
+			(link)->prev->next = (link);                                       \
+		else                                                                   \
+			(head) = (link);                                                   \
+		(tail) = (link);                                                       \
+	BLOCK_END
+
+#define LIST_UNLINK_WITH_TAIL(head, tail, link)                                \
+	BLOCK_START                                                                \
+		if ((tail) == (link))                                                  \
+			(tail) = (link)->prev;                                             \
+		LIST_UNLINK ((head), (link));                                          \
+	BLOCK_END
+
+#define LIST_FOR_EACH(type, iter, list)                                        \
+	for (type *iter = (list), *next;                                           \
+		(iter && (next = iter->next)) || iter;                                 \
+		iter = next)
+
+// --- Dynamically allocated string array --------------------------------------
+
+struct str_vector
+{
+	char **vector;
+	size_t len;
+	size_t alloc;
+};
+
+static void
+str_vector_init (struct str_vector *self)
+{
+	self->alloc = 4;
+	self->len = 0;
+	self->vector = xcalloc (sizeof *self->vector, self->alloc);
+}
+
+static void
+str_vector_free (struct str_vector *self)
+{
+	unsigned i;
+	for (i = 0; i < self->len; i++)
+		free (self->vector[i]);
+
+	free (self->vector);
+	self->vector = NULL;
+}
+
+static void
+str_vector_reset (struct str_vector *self)
+{
+	str_vector_free (self);
+	str_vector_init (self);
+}
+
+static void
+str_vector_add_owned (struct str_vector *self, char *s)
+{
+	self->vector[self->len] = s;
+	if (++self->len >= self->alloc)
+		self->vector = xreallocarray (self->vector,
+			sizeof *self->vector, (self->alloc <<= 1));
+	self->vector[self->len] = NULL;
+}
+
+static void
+str_vector_add (struct str_vector *self, const char *s)
+{
+	str_vector_add_owned (self, xstrdup (s));
+}
+
+static void
+str_vector_add_args (struct str_vector *self, const char *s, ...)
+	ATTRIBUTE_SENTINEL;
+
+static void
+str_vector_add_args (struct str_vector *self, const char *s, ...)
+{
+	va_list ap;
+
+	va_start (ap, s);
+	while (s)
+	{
+		str_vector_add (self, s);
+		s = va_arg (ap, const char *);
+	}
+	va_end (ap);
+}
+
+static void
+str_vector_add_vector (struct str_vector *self, char **vector)
+{
+	while (*vector)
+		str_vector_add (self, *vector++);
+}
+
+static void
+str_vector_remove (struct str_vector *self, size_t i)
+{
+	hard_assert (i < self->len);
+	free (self->vector[i]);
+	memmove (self->vector + i, self->vector + i + 1,
+		(self->len-- - i) * sizeof *self->vector);
+}
+
+// --- Dynamically allocated strings -------------------------------------------
+
+// Basically a string builder to abstract away manual memory management.
+
+struct str
+{
+	char *str;                          ///< String data, null terminated
+	size_t alloc;                       ///< How many bytes are allocated
+	size_t len;                         ///< How long the string actually is
+};
+
+/// We don't care about allocations that are way too large for the content, as
+/// long as the allocation is below the given threshold.  (Trivial heuristics.)
+#define STR_SHRINK_THRESHOLD (1 << 20)
+
+static void
+str_init (struct str *self)
+{
+	self->alloc = 16;
+	self->len = 0;
+	self->str = strcpy (xmalloc (self->alloc), "");
+}
+
+static void
+str_free (struct str *self)
+{
+	free (self->str);
+	self->str = NULL;
+	self->alloc = 0;
+	self->len = 0;
+}
+
+static void
+str_reset (struct str *self)
+{
+	str_free (self);
+	str_init (self);
+}
+
+static char *
+str_steal (struct str *self)
+{
+	char *str = self->str;
+	self->str = NULL;
+	str_free (self);
+	return str;
+}
+
+static void
+str_ensure_space (struct str *self, size_t n)
+{
+	// We allocate at least one more byte for the terminating null character
+	size_t new_alloc = self->alloc;
+	while (new_alloc <= self->len + n)
+		new_alloc <<= 1;
+	if (new_alloc != self->alloc)
+		self->str = xrealloc (self->str, (self->alloc = new_alloc));
+}
+
+static void
+str_append_data (struct str *self, const void *data, size_t n)
+{
+	str_ensure_space (self, n);
+	memcpy (self->str + self->len, data, n);
+	self->len += n;
+	self->str[self->len] = '\0';
+}
+
+static void
+str_append_c (struct str *self, char c)
+{
+	str_append_data (self, &c, 1);
+}
+
+static void
+str_append (struct str *self, const char *s)
+{
+	str_append_data (self, s, strlen (s));
+}
+
+static void
+str_append_str (struct str *self, const struct str *another)
+{
+	str_append_data (self, another->str, another->len);
+}
+
+static int
+str_append_vprintf (struct str *self, const char *fmt, va_list va)
+{
+	va_list ap;
+	int size;
+
+	va_copy (ap, va);
+	size = vsnprintf (NULL, 0, fmt, ap);
+	va_end (ap);
+
+	if (size < 0)
+		return -1;
+
+	va_copy (ap, va);
+	str_ensure_space (self, size);
+	size = vsnprintf (self->str + self->len, self->alloc - self->len, fmt, ap);
+	va_end (ap);
+
+	if (size > 0)
+		self->len += size;
+
+	return size;
+}
+
+static int
+str_append_printf (struct str *self, const char *fmt, ...)
+	ATTRIBUTE_PRINTF (2, 3);
+
+static int
+str_append_printf (struct str *self, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start (ap, fmt);
+	int size = str_append_vprintf (self, fmt, ap);
+	va_end (ap);
+	return size;
+}
+
+static void
+str_remove_slice (struct str *self, size_t start, size_t length)
+{
+	size_t end = start + length;
+	hard_assert (end <= self->len);
+	memmove (self->str + start, self->str + end, self->len - end);
+	self->str[self->len -= length] = '\0';
+
+	// Shrink the string if the allocation becomes way too large
+	if (self->alloc >= STR_SHRINK_THRESHOLD && self->len < (self->alloc >> 2))
+		self->str = xrealloc (self->str, self->alloc >>= 2);
+}
+
+// --- Errors ------------------------------------------------------------------
+
+// Error reporting utilities.  Inspired by GError, only much simpler.
+
+struct error
+{
+	char *message;                      ///< Textual description of the event
+};
+
+static void
+error_set (struct error **e, const char *message, ...) ATTRIBUTE_PRINTF (2, 3);
+
+static void
+error_set (struct error **e, const char *message, ...)
+{
+	if (!e)
+		return;
+
+	va_list ap;
+	va_start (ap, message);
+	int size = vsnprintf (NULL, 0, message, ap);
+	va_end (ap);
+
+	hard_assert (size >= 0);
+
+	struct error *tmp = xmalloc (sizeof *tmp);
+	tmp->message = xmalloc (size + 1);
+
+	va_start (ap, message);
+	size = vsnprintf (tmp->message, size + 1, message, ap);
+	va_end (ap);
+
+	hard_assert (size >= 0);
+
+	soft_assert (*e == NULL);
+	*e = tmp;
+}
+
+static void
+error_free (struct error *e)
+{
+	free (e->message);
+	free (e);
+}
+
+static void
+error_propagate (struct error **destination, struct error *source)
+{
+	if (!destination)
+	{
+		error_free (source);
+		return;
+	}
+
+	soft_assert (*destination == NULL);
+	*destination = source;
+}
+
+// --- String hash map ---------------------------------------------------------
+
+// The most basic <string, managed pointer> map (or associative array).
+
+struct str_map_link
+{
+	LIST_HEADER (struct str_map_link)
+
+	void *data;                         ///< Payload
+	size_t key_length;                  ///< Length of the key without '\0'
+	char key[];                         ///< The key for this link
+};
+
+struct str_map
+{
+	struct str_map_link **map;          ///< The hash table data itself
+	size_t alloc;                       ///< Number of allocated entries
+	size_t len;                         ///< Number of entries in the table
+	void (*free) (void *);              ///< Callback to destruct the payload
+
+	/// Callback that transforms all key values for storage and comparison;
+	/// has to behave exactly like strxfrm().
+	size_t (*key_xfrm) (char *dest, const char *src, size_t n);
+};
+
+// As long as you don't remove the current entry, you can modify the map.
+// Use `link' directly to access the data.
+
+struct str_map_iter
+{
+	struct str_map *map;                ///< The map we're iterating
+	size_t next_index;                  ///< Next table index to search
+	struct str_map_link *link;          ///< Current link
+};
+
+#define STR_MAP_MIN_ALLOC 16
+
+typedef void (*str_map_free_fn) (void *);
+
+static void
+str_map_init (struct str_map *self)
+{
+	self->alloc = STR_MAP_MIN_ALLOC;
+	self->len = 0;
+	self->free = NULL;
+	self->key_xfrm = NULL;
+	self->map = xcalloc (self->alloc, sizeof *self->map);
+}
+
+static void
+str_map_free (struct str_map *self)
+{
+	struct str_map_link **iter, **end = self->map + self->alloc;
+	struct str_map_link *link, *tmp;
+
+	for (iter = self->map; iter < end; iter++)
+		for (link = *iter; link; link = tmp)
+		{
+			tmp = link->next;
+			if (self->free)
+				self->free (link->data);
+			free (link);
+		}
+
+	free (self->map);
+	self->map = NULL;
+}
+
+static void
+str_map_iter_init (struct str_map_iter *self, struct str_map *map)
+{
+	self->map = map;
+	self->next_index = 0;
+	self->link = NULL;
+}
+
+static void *
+str_map_iter_next (struct str_map_iter *self)
+{
+	struct str_map *map = self->map;
+	if (self->link)
+		self->link = self->link->next;
+	while (!self->link)
+	{
+		if (self->next_index >= map->alloc)
+			return NULL;
+		self->link = map->map[self->next_index++];
+	}
+	return self->link->data;
+}
+
+static uint64_t
+str_map_hash (const char *s, size_t len)
+{
+	static unsigned char key[16] = "SipHash 2-4 key!";
+	return siphash (key, (const void *) s, len);
+}
+
+static uint64_t
+str_map_pos (struct str_map *self, const char *s)
+{
+	size_t mask = self->alloc - 1;
+	return str_map_hash (s, strlen (s)) & mask;
+}
+
+static uint64_t
+str_map_link_hash (struct str_map_link *self)
+{
+	return str_map_hash (self->key, self->key_length);
+}
+
+static void
+str_map_resize (struct str_map *self, size_t new_size)
+{
+	struct str_map_link **old_map = self->map;
+	size_t i, old_size = self->alloc;
+
+	// Only powers of two, so that we don't need to compute the modulo
+	hard_assert ((new_size & (new_size - 1)) == 0);
+	size_t mask = new_size - 1;
+
+	self->alloc = new_size;
+	self->map = xcalloc (self->alloc, sizeof *self->map);
+	for (i = 0; i < old_size; i++)
+	{
+		struct str_map_link *iter = old_map[i], *next_iter;
+		while (iter)
+		{
+			next_iter = iter->next;
+			uint64_t pos = str_map_link_hash (iter) & mask;
+			LIST_PREPEND (self->map[pos], iter);
+			iter = next_iter;
+		}
+	}
+
+	free (old_map);
+}
+
+static void
+str_map_set_real (struct str_map *self, const char *key, void *value)
+{
+	uint64_t pos = str_map_pos (self, key);
+	struct str_map_link *iter = self->map[pos];
+	for (; iter; iter = iter->next)
+	{
+		if (strcmp (key, iter->key))
+			continue;
+
+		// Storing the same data doesn't destroy it
+		if (self->free && value != iter->data)
+			self->free (iter->data);
+
+		if (value)
+		{
+			iter->data = value;
+			return;
+		}
+
+		LIST_UNLINK (self->map[pos], iter);
+		free (iter);
+		self->len--;
+
+		// The array should be at least 1/4 full
+		if (self->alloc >= (STR_MAP_MIN_ALLOC << 2)
+		 && self->len < (self->alloc >> 2))
+			str_map_resize (self, self->alloc >> 2);
+		return;
+	}
+
+	if (!value)
+		return;
+
+	if (self->len >= self->alloc)
+	{
+		str_map_resize (self, self->alloc << 1);
+		pos = str_map_pos (self, key);
+	}
+
+	// Link in a new element for the given <key, value> pair
+	size_t key_length = strlen (key);
+	struct str_map_link *link = xmalloc (sizeof *link + key_length + 1);
+	link->data = value;
+	link->key_length = key_length;
+	memcpy (link->key, key, key_length + 1);
+
+	LIST_PREPEND (self->map[pos], link);
+	self->len++;
+}
+
+static void
+str_map_set (struct str_map *self, const char *key, void *value)
+{
+	if (!self->key_xfrm)
+	{
+		str_map_set_real (self, key, value);
+		return;
+	}
+	char tmp[self->key_xfrm (NULL, key, 0) + 1];
+	self->key_xfrm (tmp, key, sizeof tmp);
+	str_map_set_real (self, tmp, value);
+}
+
+static void *
+str_map_find_real (struct str_map *self, const char *key)
+{
+	struct str_map_link *iter = self->map[str_map_pos (self, key)];
+	for (; iter; iter = iter->next)
+		if (!strcmp (key, (const char *) iter + sizeof *iter))
+			return iter->data;
+	return NULL;
+}
+
+static void *
+str_map_find (struct str_map *self, const char *key)
+{
+	if (!self->key_xfrm)
+		return str_map_find_real (self, key);
+
+	char tmp[self->key_xfrm (NULL, key, 0) + 1];
+	self->key_xfrm (tmp, key, sizeof tmp);
+	return str_map_find_real (self, tmp);
+}
+
+// --- File descriptor utilities -----------------------------------------------
+
+static void
+set_cloexec (int fd)
+{
+	soft_assert (fcntl (fd, F_SETFD, fcntl (fd, F_GETFD) | FD_CLOEXEC) != -1);
+}
+
+static bool
+set_blocking (int fd, bool blocking)
+{
+	int flags = fcntl (fd, F_GETFL);
+	hard_assert (flags != -1);
+
+	bool prev = !(flags & O_NONBLOCK);
+	if (blocking)
+		flags &= ~O_NONBLOCK;
+	else
+		flags |=  O_NONBLOCK;
+
+	hard_assert (fcntl (fd, F_SETFL, flags) != -1);
+	return prev;
+}
+
+static void
+xclose (int fd)
+{
+	while (close (fd) == -1)
+		if (!soft_assert (errno == EINTR))
+			break;
+}
+
+// --- Event loop --------------------------------------------------------------
+
+#ifdef LIBERTY_WANT_POLLER
+
+// Basically the poor man's GMainLoop/libev/libuv.  It might make some sense
+// to instead use those tested and proven libraries but we don't need much
+// and it's interesting to implement.
+
+// Actually it mustn't be totally shitty as scanning exercises it quite a bit.
+// We sacrifice some memory to allow for O(1) and O(log n) operations.
+
+typedef void (*poller_fd_fn) (const struct pollfd *, void *);
+typedef void (*poller_timer_fn) (void *);
+typedef void (*poller_idle_fn) (void *);
+
+#define POLLER_MIN_ALLOC 16
+
+struct poller_timer
+{
+	struct poller_timers *timers;       ///< The timers part of our poller
+	ssize_t index;                      ///< Where we are in the array, or -1
+
+	int64_t when;                       ///< When is the timer to expire
+
+	poller_timer_fn dispatcher;         ///< Event dispatcher
+	void *user_data;                    ///< User data
+};
+
+struct poller_fd
+{
+	struct poller *poller;              ///< Our poller
+	ssize_t index;                      ///< Where we are in the array, or -1
+
+	int fd;                             ///< Our file descriptor
+	short events;                       ///< The poll() events we registered for
+	bool closed;                        ///< Whether fd has been closed already
+
+	poller_fd_fn dispatcher;            ///< Event dispatcher
+	void *user_data;                    ///< User data
+};
+
+struct poller_idle
+{
+	LIST_HEADER (struct poller_idle)
+	struct poller *poller;              ///< Our poller
+
+	bool active;                        ///< Whether we're on the list
+
+	poller_idle_fn dispatcher;          ///< Event dispatcher
+	void *user_data;                    ///< User data
+};
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+struct poller_timers
+{
+	struct poller_timer **heap;         ///< Min-heap of timers
+	size_t len;                         ///< Number of scheduled timers
+	size_t alloc;                       ///< Number of timers allocated
+};
+
+static void
+poller_timers_init (struct poller_timers *self)
+{
+	self->alloc = POLLER_MIN_ALLOC;
+	self->len = 0;
+	self->heap = xmalloc (self->alloc * sizeof *self->heap);
+}
+
+static void
+poller_timers_free (struct poller_timers *self)
+{
+	free (self->heap);
+}
+
+static int64_t
+poller_timers_get_current_time (void)
+{
+#ifdef _POSIX_TIMERS
+	struct timespec tp;
+	hard_assert (clock_gettime (CLOCK_BEST, &tp) != -1);
+	return (int64_t) tp.tv_sec * 1000 + (int64_t) tp.tv_nsec / 1000000;
+#else
+	struct timeval tp;
+	gettimeofday (&tp, NULL);
+	return (int64_t) tp.tv_sec * 1000 + (int64_t) tp.tv_usec / 1000;
+#endif
+}
+
+static void
+poller_timers_heapify_down (struct poller_timers *self, size_t index)
+{
+	typedef struct poller_timer *timer_t;
+	timer_t *end = self->heap + self->len;
+
+	while (true)
+	{
+		timer_t *parent = self->heap + index;
+		timer_t *left   = self->heap + 2 * index + 1;
+		timer_t *right  = self->heap + 2 * index + 2;
+
+		timer_t *lowest = parent;
+		if (left  < end && (*left) ->when < (*lowest)->when)
+			lowest = left;
+		if (right < end && (*right)->when < (*lowest)->when)
+			lowest = right;
+		if (parent == lowest)
+			break;
+
+		timer_t tmp = *parent;
+		*parent = *lowest;
+		*lowest = tmp;
+
+		(*parent)->index = parent - self->heap;
+		(*lowest)->index = lowest - self->heap;
+		index = lowest - self->heap;
+	}
+}
+
+static void
+poller_timers_remove_at_index (struct poller_timers *self, size_t index)
+{
+	hard_assert (index < self->len);
+	self->heap[index]->index = -1;
+	if (index == --self->len)
+		return;
+
+	self->heap[index] = self->heap[self->len];
+	self->heap[index]->index = index;
+	poller_timers_heapify_down (self, index);
+}
+
+static void
+poller_timers_dispatch (struct poller_timers *self)
+{
+	int64_t now = poller_timers_get_current_time ();
+	while (self->len && self->heap[0]->when <= now)
+	{
+		struct poller_timer *timer = self->heap[0];
+		poller_timers_remove_at_index (self, 0);
+		timer->dispatcher (timer->user_data);
+	}
+}
+
+static void
+poller_timers_heapify_up (struct poller_timers *self, size_t index)
+{
+	while (index != 0)
+	{
+		size_t parent = (index - 1) / 2;
+		if (self->heap[parent]->when <= self->heap[index]->when)
+			break;
+
+		struct poller_timer *tmp = self->heap[parent];
+		self->heap[parent] = self->heap[index];
+		self->heap[index] = tmp;
+
+		self->heap[parent]->index = parent;
+		self->heap[index] ->index = index;
+		index = parent;
+	}
+}
+
+static void
+poller_timers_set (struct poller_timers *self, struct poller_timer *timer)
+{
+	hard_assert (timer->timers == self);
+	if (timer->index != -1)
+	{
+		poller_timers_heapify_down (self, timer->index);
+		poller_timers_heapify_up (self, timer->index);
+		return;
+	}
+
+	if (self->len == self->alloc)
+		self->heap = xreallocarray (self->heap,
+			self->alloc <<= 1, sizeof *self->heap);
+	self->heap[self->len] = timer;
+	timer->index = self->len;
+	poller_timers_heapify_up (self, self->len++);
+}
+
+static int
+poller_timers_get_poll_timeout (struct poller_timers *self)
+{
+	if (!self->len)
+		return -1;
+
+	int64_t timeout = self->heap[0]->when - poller_timers_get_current_time ();
+	if (timeout <= 0)
+		return 0;
+	if (timeout > INT_MAX)
+		return INT_MAX;
+	return timeout;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static void
+poller_idle_dispatch (struct poller_idle *list)
+{
+	struct poller_idle *iter, *next;
+	for (iter = list; iter; iter = next)
+	{
+		next = iter->next;
+		iter->dispatcher (iter->user_data);
+	}
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+#ifdef __linux__
+#include <sys/epoll.h>
+
+struct poller
+{
+	int epoll_fd;                       ///< The epoll FD
+	struct poller_fd **fds;             ///< Information associated with each FD
+	int *dummy;                         ///< For poller_remove_from_dispatch()
+	struct epoll_event *revents;        ///< Output array for epoll_wait()
+	size_t len;                         ///< Number of polled descriptors
+	size_t alloc;                       ///< Number of entries allocated
+
+	struct poller_timers timers;        ///< Timeouts
+	struct poller_idle *idle;           ///< Idle events
+
+	int revents_len;                    ///< Number of entries in `revents'
+};
+
+static void
+poller_init (struct poller *self)
+{
+	self->epoll_fd = epoll_create (POLLER_MIN_ALLOC);
+	hard_assert (self->epoll_fd != -1);
+	set_cloexec (self->epoll_fd);
+
+	self->len = 0;
+	self->alloc = POLLER_MIN_ALLOC;
+	self->fds = xcalloc (self->alloc, sizeof *self->fds);
+	self->dummy = xcalloc (self->alloc, sizeof *self->dummy);
+	self->revents = xcalloc (self->alloc, sizeof *self->revents);
+	self->revents_len = 0;
+
+	poller_timers_init (&self->timers);
+	self->idle = NULL;
+}
+
+static void
+poller_free (struct poller *self)
+{
+	for (size_t i = 0; i < self->len; i++)
+	{
+		struct poller_fd *fd = self->fds[i];
+		hard_assert (epoll_ctl (self->epoll_fd,
+			EPOLL_CTL_DEL, fd->fd, (void *) "") != -1);
+	}
+
+	poller_timers_free (&self->timers);
+
+	xclose (self->epoll_fd);
+	free (self->fds);
+	free (self->dummy);
+	free (self->revents);
+}
+
+static void
+poller_ensure_space (struct poller *self)
+{
+	if (self->len < self->alloc)
+		return;
+
+	self->alloc <<= 1;
+	hard_assert (self->alloc != 0);
+
+	self->revents = xreallocarray
+		(self->revents, sizeof *self->revents, self->alloc);
+	self->fds = xreallocarray
+		(self->fds, sizeof *self->fds, self->alloc);
+	self->dummy = xreallocarray
+		(self->dummy, sizeof *self->dummy, self->alloc);
+}
+
+static short
+poller_epoll_to_poll_events (uint32_t events)
+{
+	short result = 0;
+	if (events & EPOLLIN)   result |= POLLIN;
+	if (events & EPOLLOUT)  result |= POLLOUT;
+	if (events & EPOLLERR)  result |= POLLERR;
+	if (events & EPOLLHUP)  result |= POLLHUP;
+	if (events & EPOLLPRI)  result |= POLLPRI;
+	return result;
+}
+
+static uint32_t
+poller_poll_to_epoll_events (short events)
+{
+	uint32_t result = 0;
+	if (events & POLLIN)   result |= EPOLLIN;
+	if (events & POLLOUT)  result |= EPOLLOUT;
+	if (events & POLLERR)  result |= EPOLLERR;
+	if (events & POLLHUP)  result |= EPOLLHUP;
+	if (events & POLLPRI)  result |= EPOLLPRI;
+	return result;
+}
+
+static void
+poller_set (struct poller *self, struct poller_fd *fd)
+{
+	hard_assert (fd->poller == self);
+	bool modifying = true;
+	if (fd->index == -1)
+	{
+		poller_ensure_space (self);
+		self->fds[fd->index = self->len++] = fd;
+		modifying = false;
+	}
+
+	struct epoll_event event;
+	event.events = poller_poll_to_epoll_events (fd->events);
+	event.data.ptr = fd;
+	hard_assert (epoll_ctl (self->epoll_fd,
+		modifying ? EPOLL_CTL_MOD : EPOLL_CTL_ADD, fd->fd, &event) != -1);
+}
+
+static int
+poller_compare_fds (const void *ax, const void *bx)
+{
+	const struct epoll_event *ay = ax, *by = bx;
+	struct poller_fd *a = ay->data.ptr, *b = by->data.ptr;
+	return a->fd - b->fd;
+}
+
+static void
+poller_remove_from_dispatch (struct poller *self, const struct poller_fd *fd)
+{
+	if (!self->revents_len)
+		return;
+
+	struct epoll_event key = { .data.ptr = (void *) fd }, *fd_event;
+	if ((fd_event = bsearch (&key, self->revents,
+		self->revents_len, sizeof *self->revents, poller_compare_fds)))
+	{
+		fd_event->events = -1;
+
+		// Don't let any further bsearch()'s touch possibly freed memory
+		int *dummy = self->dummy + (fd_event - self->revents);
+		*dummy = fd->fd;
+		fd_event->data.ptr =
+			(uint8_t *) dummy - offsetof (struct poller_fd, fd);
+	}
+}
+
+static void
+poller_remove_at_index (struct poller *self, size_t index)
+{
+	hard_assert (index < self->len);
+	struct poller_fd *fd = self->fds[index];
+	fd->index = -1;
+
+	poller_remove_from_dispatch (self, fd);
+	if (!fd->closed)
+		hard_assert (epoll_ctl (self->epoll_fd,
+			EPOLL_CTL_DEL, fd->fd, (void *) "") != -1);
+
+	if (index != --self->len)
+	{
+		self->fds[index] = self->fds[self->len];
+		self->fds[index]->index = index;
+	}
+}
+
+static void
+poller_run (struct poller *self)
+{
+	// Not reentrant
+	hard_assert (!self->revents_len);
+
+	int n_fds;
+	do
+		n_fds = epoll_wait (self->epoll_fd, self->revents, self->len,
+			self->idle ? 0 : poller_timers_get_poll_timeout (&self->timers));
+	while (n_fds == -1 && errno == EINTR);
+
+	if (n_fds == -1)
+		exit_fatal ("%s: %s", "epoll", strerror (errno));
+
+	// Sort them by file descriptor number for binary search
+	qsort (self->revents, n_fds, sizeof *self->revents, poller_compare_fds);
+	self->revents_len = n_fds;
+
+	poller_timers_dispatch (&self->timers);
+	poller_idle_dispatch (self->idle);
+
+	for (int i = 0; i < n_fds; i++)
+	{
+		struct epoll_event *revents = self->revents + i;
+		if (revents->events == (uint32_t) -1)
+			continue;
+
+		struct poller_fd *fd = revents->data.ptr;
+		hard_assert (fd->index != -1);
+
+		struct pollfd pfd;
+		pfd.fd = fd->fd;
+		pfd.revents = poller_epoll_to_poll_events (revents->events);
+		pfd.events = fd->events;
+
+		fd->dispatcher (&pfd, fd->user_data);
+	}
+
+	self->revents_len = 0;
+}
+
+#else  // ! __linux__
+
+struct poller
+{
+	struct pollfd *fds;                 ///< Polled descriptors
+	struct poller_fd **fds_data;        ///< Additional information for each FD
+	size_t len;                         ///< Number of polled descriptors
+	size_t alloc;                       ///< Number of entries allocated
+
+	struct poller_timers timers;        ///< Timers
+	struct poller_idle *idle;           ///< Idle events
+	int dispatch_next;                  ///< The next dispatched FD or -1
+};
+
+static void
+poller_init (struct poller *self)
+{
+	self->alloc = POLLER_MIN_ALLOC;
+	self->len = 0;
+	self->fds = xcalloc (self->alloc, sizeof *self->fds);
+	self->fds_data = xcalloc (self->alloc, sizeof *self->fds_data);
+	poller_timers_init (&self->timers);
+	self->dispatch_next = -1;
+}
+
+static void
+poller_free (struct poller *self)
+{
+	free (self->fds);
+	free (self->fds_data);
+	poller_timers_free (&self->timers);
+}
+
+static void
+poller_ensure_space (struct poller *self)
+{
+	if (self->len < self->alloc)
+		return;
+
+	self->alloc <<= 1;
+	self->fds = xreallocarray (self->fds, sizeof *self->fds, self->alloc);
+	self->fds_data = xreallocarray
+		(self->fds_data, sizeof *self->fds_data, self->alloc);
+}
+
+static void
+poller_set (struct poller *self, struct poller_fd *fd)
+{
+	hard_assert (fd->poller == self);
+	if (fd->index == -1)
+	{
+		poller_ensure_space (self);
+		self->fds_data[fd->index = self->len++] = fd;
+	}
+
+	struct pollfd *new_entry = self->fds + fd->index;
+	memset (new_entry, 0, sizeof *new_entry);
+	new_entry->fd = fd->fd;
+	new_entry->events = fd->events;
+}
+
+static void
+poller_remove_at_index (struct poller *self, size_t index)
+{
+	hard_assert (index < self->len);
+	struct poller_fd *fd = self->fds_data[index];
+	fd->index = -1;
+
+	if (index == --self->len)
+		return;
+
+	// Make sure that we don't disrupt the dispatch loop; kind of crude
+	if ((int) index < self->dispatch_next)
+	{
+		memmove (self->fds + index, self->fds + index + 1,
+			(self->len - index) * sizeof *self->fds);
+		memmove (self->fds_data + index, self->fds_data + index + 1,
+			(self->len - index) * sizeof *self->fds_data);
+		for (size_t i = index; i < self->len; i++)
+			self->fds_data[i]->index = i;
+
+		self->dispatch_next--;
+	}
+	else
+	{
+		self->fds[index]      = self->fds     [self->len];
+		self->fds_data[index] = self->fds_data[self->len];
+		self->fds_data[index]->index = index;
+	}
+}
+
+static void
+poller_run (struct poller *self)
+{
+	// Not reentrant
+	hard_assert (self->dispatch_next == -1);
+
+	int result;
+	do
+		result = poll (self->fds, self->len,
+			self->idle ? 0 : poller_timers_get_poll_timeout (&self->timers));
+	while (result == -1 && errno == EINTR);
+
+	if (result == -1)
+		exit_fatal ("%s: %s", "poll", strerror (errno));
+
+	poller_timers_dispatch (&self->timers);
+	poller_idle_dispatch (self->idle);
+
+	for (int i = 0; i < (int) self->len; )
+	{
+		struct pollfd pfd = self->fds[i];
+		struct poller_fd *fd = self->fds_data[i];
+		self->dispatch_next = ++i;
+		if (pfd.revents)
+			fd->dispatcher (&pfd, fd->user_data);
+		i = self->dispatch_next;
+	}
+
+	self->dispatch_next = -1;
+}
+
+#endif  // ! __linux__
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static void
+poller_timer_init (struct poller_timer *self, struct poller *poller)
+{
+	memset (self, 0, sizeof *self);
+	self->timers = &poller->timers;
+	self->index = -1;
+}
+
+static void
+poller_timer_set (struct poller_timer *self, int timeout_ms)
+{
+	self->when = poller_timers_get_current_time () + timeout_ms;
+	poller_timers_set (self->timers, self);
+}
+
+static void
+poller_timer_reset (struct poller_timer *self)
+{
+	if (self->index != -1)
+		poller_timers_remove_at_index (self->timers, self->index);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static void
+poller_idle_init (struct poller_idle *self, struct poller *poller)
+{
+	memset (self, 0, sizeof *self);
+	self->poller = poller;
+}
+
+static void
+poller_idle_set (struct poller_idle *self)
+{
+	if (self->active)
+		return;
+
+	LIST_PREPEND (self->poller->idle, self);
+	self->active = true;
+}
+
+static void
+poller_idle_reset (struct poller_idle *self)
+{
+	if (!self->active)
+		return;
+
+	LIST_UNLINK (self->poller->idle, self);
+	self->prev = NULL;
+	self->next = NULL;
+	self->active = false;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static void
+poller_fd_init (struct poller_fd *self, struct poller *poller, int fd)
+{
+	memset (self, 0, sizeof *self);
+	self->poller = poller;
+	self->index = -1;
+	self->fd = fd;
+}
+
+static void
+poller_fd_set (struct poller_fd *self, short events)
+{
+	self->events = events;
+	poller_set (self->poller, self);
+}
+
+static void
+poller_fd_reset (struct poller_fd *self)
+{
+	if (self->index != -1)
+		poller_remove_at_index (self->poller, self->index);
+}
+
+#endif // LIBERTY_WANT_POLLER
+
+// --- libuv-style write adaptor -----------------------------------------------
+
+// Makes it possible to use iovec to write multiple data chunks at once.
+
+typedef struct write_req write_req_t;
+struct write_req
+{
+	LIST_HEADER (write_req_t)
+	struct iovec data;                  ///< Data to be written
+};
+
+typedef struct write_queue write_queue_t;
+struct write_queue
+{
+	write_req_t *head;                  ///< The head of the queue
+	write_req_t *tail;                  ///< The tail of the queue
+	size_t head_offset;                 ///< Offset into the head
+	size_t len;
+};
+
+static void
+write_queue_init (struct write_queue *self)
+{
+	self->head = self->tail = NULL;
+	self->head_offset = 0;
+	self->len = 0;
+}
+
+static void
+write_queue_free (struct write_queue *self)
+{
+	for (write_req_t *iter = self->head, *next; iter; iter = next)
+	{
+		next = iter->next;
+		free (iter->data.iov_base);
+		free (iter);
+	}
+}
+
+static void
+write_queue_add (struct write_queue *self, write_req_t *req)
+{
+	LIST_APPEND_WITH_TAIL (self->head, self->tail, req);
+	self->len++;
+}
+
+static void
+write_queue_processed (struct write_queue *self, size_t len)
+{
+	while (self->head
+		&& self->head_offset + len >= self->head->data.iov_len)
+	{
+		write_req_t *head = self->head;
+		len -= (head->data.iov_len - self->head_offset);
+		self->head_offset = 0;
+
+		LIST_UNLINK_WITH_TAIL (self->head, self->tail, head);
+		self->len--;
+		free (head->data.iov_base);
+		free (head);
+	}
+	self->head_offset += len;
+}
+
+static bool
+write_queue_is_empty (struct write_queue *self)
+{
+	return self->head == NULL;
+}
+
+// --- Message reader ----------------------------------------------------------
+
+struct msg_reader
+{
+	struct str buf;                     ///< Input buffer
+	uint64_t offset;                    ///< Current offset in the buffer
+};
+
+static void
+msg_reader_init (struct msg_reader *self)
+{
+	str_init (&self->buf);
+	self->offset = 0;
+}
+
+static void
+msg_reader_free (struct msg_reader *self)
+{
+	str_free (&self->buf);
+}
+
+static void
+msg_reader_compact (struct msg_reader *self)
+{
+	str_remove_slice (&self->buf, 0, self->offset);
+	self->offset = 0;
+}
+
+static void
+msg_reader_feed (struct msg_reader *self, const void *data, size_t len)
+{
+	// TODO: have some mechanism to prevent flooding
+	msg_reader_compact (self);
+	str_append_data (&self->buf, data, len);
+}
+
+static void *
+msg_reader_get (struct msg_reader *self, size_t *len)
+{
+	// Try to read in the length of the message
+	if (self->offset + sizeof (uint64_t) > self->buf.len)
+		return NULL;
+
+	uint8_t *x = (uint8_t *) self->buf.str + self->offset;
+	uint64_t msg_len
+		= (uint64_t) x[0] << 56 | (uint64_t) x[1] << 48
+		| (uint64_t) x[2] << 40 | (uint64_t) x[3] << 32
+		| (uint64_t) x[4] << 24 | (uint64_t) x[5] << 16
+		| (uint64_t) x[6] << 8  | (uint64_t) x[7];
+
+	if (msg_len < sizeof msg_len)
+	{
+		// The message is shorter than its header
+		// TODO: have some mechanism to report errors
+		return NULL;
+	}
+
+	if (self->offset + msg_len < self->offset)
+	{
+		// Trying to read an insane amount of data but whatever
+		msg_reader_compact (self);
+		return NULL;
+	}
+
+	// Check if we've got the full message in the buffer and return it
+	if (self->offset + msg_len > self->buf.len)
+		return NULL;
+
+	// We have to subtract the header from the reported length
+	void *data = self->buf.str + self->offset + sizeof msg_len;
+	self->offset += msg_len;
+	*len = msg_len - sizeof msg_len;
+	return data;
+}
+
+// --- Message unpacker --------------------------------------------------------
+
+struct msg_unpacker
+{
+	const char *data;
+	size_t offset;
+	size_t len;
+};
+
+static void
+msg_unpacker_init (struct msg_unpacker *self, const void *data, size_t len)
+{
+	self->data = data;
+	self->len = len;
+	self->offset = 0;
+}
+
+static size_t
+msg_unpacker_get_available (struct msg_unpacker *self)
+{
+	return self->len - self->offset;
+}
+
+#define UNPACKER_INT_BEGIN                                                     \
+	if (self->len - self->offset < sizeof *value)                              \
+		return false;                                                          \
+	uint8_t *x = (uint8_t *) self->data + self->offset;                        \
+	self->offset += sizeof *value;
+
+static bool
+msg_unpacker_u8 (struct msg_unpacker *self, uint8_t *value)
+{
+	UNPACKER_INT_BEGIN
+	*value = x[0];
+	return true;
+}
+
+static bool
+msg_unpacker_i32 (struct msg_unpacker *self, int32_t *value)
+{
+	UNPACKER_INT_BEGIN
+	*value
+		= (uint32_t) x[0] << 24 | (uint32_t) x[1] << 16
+		| (uint32_t) x[2] << 8  | (uint32_t) x[3];
+	return true;
+}
+
+static bool
+msg_unpacker_u64 (struct msg_unpacker *self, uint64_t *value)
+{
+	UNPACKER_INT_BEGIN
+	*value
+		= (uint64_t) x[0] << 56 | (uint64_t) x[1] << 48
+		| (uint64_t) x[2] << 40 | (uint64_t) x[3] << 32
+		| (uint64_t) x[4] << 24 | (uint64_t) x[5] << 16
+		| (uint64_t) x[6] << 8  | (uint64_t) x[7];
+	return true;
+}
+
+#undef UNPACKER_INT_BEGIN
+
+// --- Message packer and writer -----------------------------------------------
+
+struct msg_writer
+{
+	struct str buf;                     ///< Holds the message data
+};
+
+static void
+msg_writer_init (struct msg_writer *self)
+{
+	str_init (&self->buf);
+	// Placeholder for message length
+	str_append_data (&self->buf, "\x00\x00\x00\x00" "\x00\x00\x00\x00", 8);
+}
+
+static void
+msg_writer_u8 (struct msg_writer *self, uint8_t x)
+{
+	str_append_data (&self->buf, &x, 1);
+}
+
+static void
+msg_writer_i32 (struct msg_writer *self, int32_t x)
+{
+	uint32_t u = x;
+	uint8_t tmp[4] = { u >> 24, u >> 16, u >> 8, u };
+	str_append_data (&self->buf, tmp, sizeof tmp);
+}
+
+static void
+msg_writer_u64 (struct msg_writer *self, uint64_t x)
+{
+	uint8_t tmp[8] =
+		{ x >> 56, x >> 48, x >> 40, x >> 32, x >> 24, x >> 16, x >> 8, x };
+	str_append_data (&self->buf, tmp, sizeof tmp);
+}
+
+static void *
+msg_writer_flush (struct msg_writer *self, size_t *len)
+{
+	// Update the message length
+	uint64_t x = self->buf.len;
+	uint8_t tmp[8] =
+		{ x >> 56, x >> 48, x >> 40, x >> 32, x >> 24, x >> 16, x >> 8, x };
+	memcpy (self->buf.str, tmp, sizeof tmp);
+
+	*len = x;
+	return str_steal (&self->buf);
+}
+
+// --- Utilities ---------------------------------------------------------------
+
+static void
+split_str_ignore_empty (const char *s, char delimiter, struct str_vector *out)
+{
+	const char *begin = s, *end;
+
+	while ((end = strchr (begin, delimiter)))
+	{
+		if (begin != end)
+			str_vector_add_owned (out, xstrndup (begin, end - begin));
+		begin = ++end;
+	}
+
+	if (*begin)
+		str_vector_add (out, begin);
+}
+
+static char *
+strip_str_in_place (char *s, const char *stripped_chars)
+{
+	char *end = s + strlen (s);
+	while (end > s && strchr (stripped_chars, end[-1]))
+		*--end = '\0';
+
+	char *start = s + strspn (s, stripped_chars);
+	if (start > s)
+		memmove (s, start, end - start + 1);
+	return s;
+}
+
+static char *
+join_str_vector (const struct str_vector *v, char delimiter)
+{
+	if (!v->len)
+		return xstrdup ("");
+
+	struct str result;
+	str_init (&result);
+	str_append (&result, v->vector[0]);
+	for (size_t i = 1; i < v->len; i++)
+		str_append_printf (&result, "%c%s", delimiter, v->vector[i]);
+	return str_steal (&result);
+}
+
+static char *xstrdup_printf (const char *, ...) ATTRIBUTE_PRINTF (1, 2);
+
+static char *
+xstrdup_printf (const char *format, ...)
+{
+	va_list ap;
+	struct str tmp;
+	str_init (&tmp);
+	va_start (ap, format);
+	str_append_vprintf (&tmp, format, ap);
+	va_end (ap);
+	return str_steal (&tmp);
+}
+
+static char *
+iconv_xstrdup (iconv_t conv, char *in, size_t in_len, size_t *out_len)
+{
+	char *buf, *buf_ptr;
+	size_t out_left, buf_alloc;
+
+	buf = buf_ptr = xmalloc (out_left = buf_alloc = 64);
+
+	char *in_ptr = in;
+	if (in_len == (size_t) -1)
+		in_len = strlen (in) + 1;
+
+	while (iconv (conv, (char **) &in_ptr, &in_len,
+		(char **) &buf_ptr, &out_left) == (size_t) -1)
+	{
+		if (errno != E2BIG)
+		{
+			free (buf);
+			return NULL;
+		}
+		out_left += buf_alloc;
+		char *new_buf = xrealloc (buf, buf_alloc <<= 1);
+		buf_ptr += new_buf - buf;
+		buf = new_buf;
+	}
+	if (out_len)
+		*out_len = buf_alloc - out_left;
+	return buf;
+}
+
+static bool
+str_append_env_path (struct str *output, const char *var, bool only_absolute)
+{
+	const char *value = getenv (var);
+
+	if (!value || (only_absolute && *value != '/'))
+		return false;
+
+	str_append (output, value);
+	return true;
+}
+
+static void
+get_xdg_home_dir (struct str *output, const char *var, const char *def)
+{
+	str_reset (output);
+	if (!str_append_env_path (output, var, true))
+	{
+		str_append_env_path (output, "HOME", false);
+		str_append_c (output, '/');
+		str_append (output, def);
+	}
+}
+
+static void
+get_xdg_config_dirs (struct str_vector *out)
+{
+	struct str config_home;
+	str_init (&config_home);
+	get_xdg_home_dir (&config_home, "XDG_CONFIG_HOME", ".config");
+	str_vector_add (out, config_home.str);
+	str_free (&config_home);
+
+	const char *xdg_config_dirs;
+	if ((xdg_config_dirs = getenv ("XDG_CONFIG_DIRS")))
+		split_str_ignore_empty (xdg_config_dirs, ':', out);
+}
+
+static char *
+resolve_config_filename (const char *filename)
+{
+	// Absolute path is absolute
+	if (*filename == '/')
+		return xstrdup (filename);
+
+	struct str_vector paths;
+	str_vector_init (&paths);
+	get_xdg_config_dirs (&paths);
+
+	struct str file;
+	str_init (&file);
+
+	char *result = NULL;
+	for (unsigned i = 0; i < paths.len; i++)
+	{
+		// As per spec, relative paths are ignored
+		if (*paths.vector[i] != '/')
+			continue;
+
+		str_reset (&file);
+		str_append_printf (&file, "%s/" PROGRAM_NAME "/%s",
+			paths.vector[i], filename);
+
+		struct stat st;
+		if (!stat (file.str, &st))
+		{
+			result = str_steal (&file);
+			break;
+		}
+	}
+
+	str_vector_free (&paths);
+	str_free (&file);
+	return result;
+}
+
+static bool
+ensure_directory_existence (const char *path, struct error **e)
+{
+	struct stat st;
+
+	if (stat (path, &st))
+	{
+		if (mkdir (path, S_IRWXU | S_IRWXG | S_IRWXO))
+		{
+			error_set (e, "cannot create directory `%s': %s",
+				path, strerror (errno));
+			return false;
+		}
+	}
+	else if (!S_ISDIR (st.st_mode))
+	{
+		error_set (e, "cannot create directory `%s': %s",
+			path, "file exists but is not a directory");
+		return false;
+	}
+	return true;
+}
+
+static bool
+mkdir_with_parents (char *path, struct error **e)
+{
+	char *p = path;
+
+	// XXX: This is prone to the TOCTTOU problem.  The solution would be to
+	//   rewrite the function using the {mkdir,fstat}at() functions from
+	//   POSIX.1-2008, ideally returning a file descriptor to the open
+	//   directory, with the current code as a fallback.  Or to use chdir().
+	while ((p = strchr (p + 1, '/')))
+	{
+		*p = '\0';
+		bool success = ensure_directory_existence (path, e);
+		*p = '/';
+
+		if (!success)
+			return false;
+	}
+
+	return ensure_directory_existence (path, e);
+}
+
+static bool
+set_boolean_if_valid (bool *out, const char *s)
+{
+	if      (!strcasecmp (s, "yes"))    *out = true;
+	else if (!strcasecmp (s, "no"))     *out = false;
+	else if (!strcasecmp (s, "on"))     *out = true;
+	else if (!strcasecmp (s, "off"))    *out = false;
+	else if (!strcasecmp (s, "true"))   *out = true;
+	else if (!strcasecmp (s, "false"))  *out = false;
+	else return false;
+
+	return true;
+}
+
+static bool
+xstrtoul (unsigned long *out, const char *s, int base)
+{
+	char *end;
+	errno = 0;
+	*out = strtoul (s, &end, base);
+	return errno == 0 && !*end && end != s;
+}
+
+static bool
+read_line (FILE *fp, struct str *s)
+{
+	int c;
+	bool at_end = true;
+
+	str_reset (s);
+	while ((c = fgetc (fp)) != EOF)
+	{
+		at_end = false;
+		if (c == '\r')
+			continue;
+		if (c == '\n')
+			break;
+		str_append_c (s, c);
+	}
+
+	return !at_end;
+}
+
+static char *
+format_host_port_pair (const char *host, const char *port)
+{
+	// IPv6 addresses mess with the "colon notation"; let's go with RFC 2732
+	if (strchr (host, ':'))
+		return xstrdup_printf ("[%s]:%s", host, port);
+	return xstrdup_printf ("%s:%s", host, port);
+}
+
+// --- OpenSSL -----------------------------------------------------------------
+
+#ifdef LIBERTY_WANT_SSL
+
+#define XSSL_ERROR_TRY_AGAIN INT_MAX
+
+/// A small wrapper around SSL_get_error() to simplify further handling
+static int
+xssl_get_error (SSL *ssl, int result, const char **error_info)
+{
+	int error = SSL_get_error (ssl, result);
+	switch (error)
+	{
+	case SSL_ERROR_NONE:
+	case SSL_ERROR_ZERO_RETURN:
+	case SSL_ERROR_WANT_READ:
+	case SSL_ERROR_WANT_WRITE:
+		return error;
+	case SSL_ERROR_SYSCALL:
+		if ((error = ERR_get_error ()))
+			*error_info = ERR_error_string (error, NULL);
+		else if (result == 0)
+			// An EOF that's not according to the protocol is still an EOF
+			return SSL_ERROR_ZERO_RETURN;
+		else
+		{
+			if (errno == EINTR)
+				return XSSL_ERROR_TRY_AGAIN;
+			*error_info = strerror (errno);
+		}
+		return SSL_ERROR_SSL;
+	default:
+		if ((error = ERR_get_error ()))
+			*error_info = ERR_error_string (error, NULL);
+		else
+			*error_info = "Unknown error";
+		return SSL_ERROR_SSL;
+	}
+}
+
+#endif  // LIBERTY_WANT_SSL
+
+// --- Regular expressions -----------------------------------------------------
+
+static regex_t *
+regex_compile (const char *regex, int flags, struct error **e)
+{
+	regex_t *re = xmalloc (sizeof *re);
+	int err = regcomp (re, regex, flags);
+	if (!err)
+		return re;
+
+	char buf[regerror (err, re, NULL, 0)];
+	regerror (err, re, buf, sizeof buf);
+
+	free (re);
+	error_set (e, "%s: %s", "failed to compile regular expression", buf);
+	return NULL;
+}
+
+static void
+regex_free (void *regex)
+{
+	regfree (regex);
+	free (regex);
+}
+
+// The cost of hashing a string is likely to be significantly smaller than that
+// of compiling the whole regular expression anew, so here is a simple cache.
+// Adding basic support for subgroups is easy: check `re_nsub' and output into
+// a `struct str_vector' (if all we want is the substrings).
+
+static void
+regex_cache_init (struct str_map *cache)
+{
+	str_map_init (cache);
+	cache->free = regex_free;
+}
+
+static bool
+regex_cache_match (struct str_map *cache, const char *regex, int flags,
+	const char *s, struct error **e)
+{
+	regex_t *re = str_map_find (cache, regex);
+	if (!re)
+	{
+		re = regex_compile (regex, flags, e);
+		if (!re)
+			return false;
+		str_map_set (cache, regex, re);
+	}
+	return regexec (re, s, 0, NULL, 0) != REG_NOMATCH;
+}
+
+// --- Configuration -----------------------------------------------------------
+
+// The keys are stripped of surrounding whitespace, the values are not.
+
+struct config_item
+{
+	const char *key;
+	const char *default_value;
+	const char *description;
+};
+
+static void
+load_config_defaults (struct str_map *config, const struct config_item *table)
+{
+	for (; table->key != NULL; table++)
+		if (table->default_value)
+			str_map_set (config, table->key, xstrdup (table->default_value));
+		else
+			str_map_set (config, table->key, NULL);
+}
+
+static bool
+read_config_file (struct str_map *config, struct error **e)
+{
+	char *filename = resolve_config_filename (PROGRAM_NAME ".conf");
+	if (!filename)
+		return true;
+
+	FILE *fp = fopen (filename, "r");
+	if (!fp)
+	{
+		error_set (e, "could not open `%s' for reading: %s",
+			filename, strerror (errno));
+		free (filename);
+		return false;
+	}
+
+	struct str line;
+	str_init (&line);
+
+	bool errors = false;
+	for (unsigned line_no = 1; read_line (fp, &line); line_no++)
+	{
+		char *start = line.str;
+		if (*start == '#')
+			continue;
+
+		while (isspace (*start))
+			start++;
+
+		char *end = strchr (start, '=');
+		if (end)
+		{
+			char *value = end + 1;
+			do
+				*end = '\0';
+			while (isspace (*--end));
+
+			str_map_set (config, start, xstrdup (value));
+		}
+		else if (*start)
+		{
+			error_set (e, "line %u in config: %s", line_no, "malformed input");
+			errors = true;
+			break;
+		}
+	}
+
+	str_free (&line);
+	fclose (fp);
+	free (filename);
+	return !errors;
+}
+
+static char *
+write_default_config (const char *filename, const char *prolog,
+	const struct config_item *table, struct error **e)
+{
+	struct str path, base;
+
+	str_init (&path);
+	str_init (&base);
+
+	if (filename)
+	{
+		char *tmp = xstrdup (filename);
+		str_append (&path, dirname (tmp));
+		strcpy (tmp, filename);
+		str_append (&base, basename (tmp));
+		free (tmp);
+	}
+	else
+	{
+		get_xdg_home_dir (&path, "XDG_CONFIG_HOME", ".config");
+		str_append (&path, "/" PROGRAM_NAME);
+		str_append (&base, PROGRAM_NAME ".conf");
+	}
+
+	if (!mkdir_with_parents (path.str, e))
+		goto error;
+
+	str_append_c (&path, '/');
+	str_append_str (&path, &base);
+
+	FILE *fp = fopen (path.str, "w");
+	if (!fp)
+	{
+		error_set (e, "could not open `%s' for writing: %s",
+			path.str, strerror (errno));
+		goto error;
+	}
+
+	if (prolog)
+		fputs (prolog, fp);
+
+	errno = 0;
+	for (; table->key != NULL; table++)
+	{
+		fprintf (fp, "# %s\n", table->description);
+		if (table->default_value)
+			fprintf (fp, "%s=%s\n", table->key, table->default_value);
+		else
+			fprintf (fp, "#%s=\n", table->key);
+	}
+	fclose (fp);
+	if (errno)
+	{
+		error_set (e, "writing to `%s' failed: %s", path.str, strerror (errno));
+		goto error;
+	}
+
+	str_free (&base);
+	return str_steal (&path);
+
+error:
+	str_free (&base);
+	str_free (&path);
+	return NULL;
+
+}
+
+static void
+call_write_default_config (const char *hint, const struct config_item *table)
+{
+	static const char *prolog =
+	"# " PROGRAM_NAME " " PROGRAM_VERSION " configuration file\n"
+	"#\n"
+	"# Relative paths are searched for in ${XDG_CONFIG_HOME:-~/.config}\n"
+	"# /" PROGRAM_NAME " as well as in $XDG_CONFIG_DIRS/" PROGRAM_NAME "\n"
+	"\n";
+
+	struct error *e = NULL;
+	char *filename = write_default_config (hint, prolog, table, &e);
+	if (!filename)
+	{
+		print_error ("%s", e->message);
+		error_free (e);
+		exit (EXIT_FAILURE);
+	}
+	print_status ("configuration written to `%s'", filename);
+	free (filename);
+}
+
+// --- Option handler ----------------------------------------------------------
+
+// Simple wrapper for the getopt_long API to make it easier to use and maintain.
+
+#define OPT_USAGE_ALIGNMENT_COLUMN 30   ///< Alignment for option descriptions
+
+enum
+{
+	OPT_OPTIONAL_ARG  = (1 << 0),       ///< The argument is optional
+	OPT_LONG_ONLY     = (1 << 1)        ///< Ignore the short name in opt_string
+};
+
+// All options need to have both a short name, and a long name.  The short name
+// is what is returned from opt_handler_get().  It is possible to define a value
+// completely out of the character range combined with the OPT_LONG_ONLY flag.
+//
+// When `arg_hint' is defined, the option is assumed to have an argument.
+
+struct opt
+{
+	int short_name;                     ///< The single-letter name
+	const char *long_name;              ///< The long name
+	const char *arg_hint;               ///< Option argument hint
+	int flags;                          ///< Option flags
+	const char *description;            ///< Option description
+};
+
+struct opt_handler
+{
+	int argc;                           ///< The number of program arguments
+	char **argv;                        ///< Program arguments
+
+	const char *arg_hint;               ///< Program arguments hint
+	const char *description;            ///< Description of the program
+
+	const struct opt *opts;             ///< The list of options
+	size_t opts_len;                    ///< The length of the option array
+
+	struct option *options;             ///< The list of options for getopt
+	char *opt_string;                   ///< The `optstring' for getopt
+};
+
+static void
+opt_handler_free (struct opt_handler *self)
+{
+	free (self->options);
+	free (self->opt_string);
+}
+
+static void
+opt_handler_init (struct opt_handler *self, int argc, char **argv,
+	const struct opt *opts, const char *arg_hint, const char *description)
+{
+	memset (self, 0, sizeof *self);
+	self->argc = argc;
+	self->argv = argv;
+	self->arg_hint = arg_hint;
+	self->description = description;
+
+	size_t len = 0;
+	for (const struct opt *iter = opts; iter->long_name; iter++)
+		len++;
+
+	self->opts = opts;
+	self->opts_len = len;
+	self->options = xcalloc (len + 1, sizeof *self->options);
+
+	struct str opt_string;
+	str_init (&opt_string);
+
+	for (size_t i = 0; i < len; i++)
+	{
+		const struct opt *opt = opts + i;
+		struct option *mapped = self->options + i;
+
+		mapped->name = opt->long_name;
+		if (!opt->arg_hint)
+			mapped->has_arg = no_argument;
+		else if (opt->flags & OPT_OPTIONAL_ARG)
+			mapped->has_arg = optional_argument;
+		else
+			mapped->has_arg = required_argument;
+		mapped->val = opt->short_name;
+
+		if (opt->flags & OPT_LONG_ONLY)
+			continue;
+
+		str_append_c (&opt_string, opt->short_name);
+		if (opt->arg_hint)
+		{
+			str_append_c (&opt_string, ':');
+			if (opt->flags & OPT_OPTIONAL_ARG)
+				str_append_c (&opt_string, ':');
+		}
+	}
+
+	self->opt_string = str_steal (&opt_string);
+}
+
+static void
+opt_handler_usage (struct opt_handler *self, FILE *stream)
+{
+	struct str usage;
+	str_init (&usage);
+
+	str_append_printf (&usage, "Usage: %s [OPTION]... %s\n",
+		self->argv[0], self->arg_hint ? self->arg_hint : "");
+	str_append_printf (&usage, "%s\n\n", self->description);
+
+	for (size_t i = 0; i < self->opts_len; i++)
+	{
+		struct str row;
+		str_init (&row);
+
+		const struct opt *opt = self->opts + i;
+		if (!(opt->flags & OPT_LONG_ONLY))
+			str_append_printf (&row, "  -%c, ", opt->short_name);
+		else
+			str_append (&row, "      ");
+		str_append_printf (&row, "--%s", opt->long_name);
+		if (opt->arg_hint)
+			str_append_printf (&row, (opt->flags & OPT_OPTIONAL_ARG)
+				? " [%s]" : " %s", opt->arg_hint);
+
+		// TODO: keep the indent if there are multiple lines
+		if (row.len + 2 <= OPT_USAGE_ALIGNMENT_COLUMN)
+		{
+			str_append (&row, "  ");
+			str_append_printf (&usage, "%-*s%s\n",
+				OPT_USAGE_ALIGNMENT_COLUMN, row.str, opt->description);
+		}
+		else
+			str_append_printf (&usage, "%s\n%-*s%s\n", row.str,
+				OPT_USAGE_ALIGNMENT_COLUMN, "", opt->description);
+
+		str_free (&row);
+	}
+
+	fputs (usage.str, stream);
+	str_free (&usage);
+}
+
+static int
+opt_handler_get (struct opt_handler *self)
+{
+	return getopt_long (self->argc, self->argv,
+		self->opt_string, self->options, NULL);
+}
+
+// --- Unit tests --------------------------------------------------------------
+
+// This is modeled after GTest, only remarkably simpler.
+
+typedef void (*test_fn) (const void *data, void *fixture);
+
+struct test_unit
+{
+	LIST_HEADER (struct test_unit)
+
+	char *name;                         ///< Name of the test
+	size_t fixture_size;                ///< Fixture size
+	const void *user_data;              ///< User data
+
+	test_fn setup;                      ///< Fixture setup callback
+	test_fn test;                       ///< The test
+	test_fn teardown;                   ///< Fixture teardown callback
+};
+
+struct test
+{
+	struct test_unit *tests;            ///< List of tests
+	struct test_unit *tests_tail;       ///< End of the list of tests
+
+	struct str_map whitelist;           ///< Whitelisted tests
+	struct str_map blacklist;           ///< Blacklisted tests
+
+	unsigned list_only : 1;             ///< Just list all tests
+};
+
+static void
+test_init (struct test *self, int argc, char **argv)
+{
+	memset (self, 0, sizeof *self);
+	str_map_init (&self->whitelist);
+	str_map_init (&self->blacklist);
+
+	static const struct opt opts[] =
+	{
+		{ 'd', "debug", NULL, 0, "run in debug mode" },
+		{ 'h', "help", NULL, 0, "display this help and exit" },
+		{ 'p', "pass", "NAME", 0, "only run tests glob-matching the name" },
+		{ 's', "skip", "NAME", 0, "skip all tests glob-matching the name" },
+		{ 'l', "list", NULL, 0, "list all available tests" },
+		{ 0, NULL, NULL, 0, NULL }
+	};
+
+	struct opt_handler oh;
+	opt_handler_init (&oh, argc, argv, opts, NULL, "Unit test runner");
+
+	int c;
+	while ((c = opt_handler_get (&oh)) != -1)
+	switch (c)
+	{
+	case 'd':
+		g_debug_mode = true;
+		break;
+	case 'h':
+		opt_handler_usage (&oh, stdout);
+		exit (EXIT_SUCCESS);
+	case 'p':
+		str_map_set (&self->whitelist, optarg, (void *) 1);
+		break;
+	case 's':
+		str_map_set (&self->blacklist, optarg, (void *) 1);
+		break;
+	case 'l':
+		self->list_only = true;
+		break;
+	default:
+		print_error ("wrong options");
+		opt_handler_usage (&oh, stderr);
+		exit (EXIT_FAILURE);
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	if (argc)
+	{
+		opt_handler_usage (&oh, stderr);
+		exit (EXIT_FAILURE);
+	}
+
+	opt_handler_free (&oh);
+}
+
+static void
+test_add_internal (struct test *self, const char *name, size_t fixture_size,
+	const void *user_data, test_fn setup, test_fn test, test_fn teardown)
+{
+	hard_assert (test != NULL);
+	hard_assert (name != NULL);
+
+	struct test_unit *unit = xcalloc (1, sizeof *unit);
+	unit->name = xstrdup (name);
+	unit->fixture_size = fixture_size;
+	unit->user_data = user_data;
+
+	unit->setup = setup;
+	unit->test = test;
+	unit->teardown = teardown;
+
+	LIST_APPEND_WITH_TAIL (self->tests, self->tests_tail, unit);
+}
+
+#define test_add(self, name, fixture_type, user_data, setup, test, teardown)   \
+	test_add_internal ((self), (name), sizeof (fixture_type), (user_data),     \
+		(test_fn) (setup), (test_fn) (test), (test_fn) (teardown))
+
+#define test_add_simple(self, name, user_data, test)                           \
+	test_add_internal ((self), (name), 0, (user_data),                         \
+		NULL, (test_fn) (test), NULL)
+
+static bool
+str_map_glob_match (struct str_map *self, const char *entry)
+{
+	struct str_map_iter iter;
+	str_map_iter_init (&iter, self);
+	while (str_map_iter_next (&iter))
+		if (!fnmatch (iter.link->key, entry, 0))
+			return true;
+	return false;
+}
+
+static bool
+test_is_allowed (struct test *self, const char *name)
+{
+	bool allowed = true;
+	if (self->whitelist.len)
+		allowed  =  str_map_glob_match (&self->whitelist, name);
+	if (self->blacklist.len)
+		allowed &= !str_map_glob_match (&self->blacklist, name);
+	return allowed;
+}
+
+static int
+test_run (struct test *self)
+{
+	g_soft_asserts_are_deadly = true;
+	LIST_FOR_EACH (struct test_unit, iter, self->tests)
+	{
+		if (!test_is_allowed (self, iter->name))
+			continue;
+
+		if (self->list_only)
+		{
+			printf ("%s\n", iter->name);
+			continue;
+		}
+
+		void *fixture = xcalloc (1, iter->fixture_size);
+		if (iter->setup)
+			iter->setup (iter->user_data, fixture);
+
+		fprintf (stderr, "%s: ", iter->name);
+		iter->test (iter->user_data, fixture);
+		fprintf (stderr, "OK\n");
+
+		if (iter->teardown)
+			iter->teardown (iter->user_data, fixture);
+		free (fixture);
+	}
+
+	LIST_FOR_EACH (struct test_unit, iter, self->tests)
+	{
+		free (iter->name);
+		free (iter);
+	}
+
+	str_map_free (&self->whitelist);
+	str_map_free (&self->blacklist);
+	return 0;
+}
diff --git a/siphash.c b/siphash.c
new file mode 100644
index 0000000..7a5c8d4
--- /dev/null
+++ b/siphash.c
@@ -0,0 +1,87 @@
+// Code taken from https://github.com/floodyberry/siphash with some edits.
+//
+// To the extent possible under law, the author(s) have dedicated all copyright
+// and related and neighboring rights to this software to the public domain
+// worldwide. This software is distributed without any warranty.
+//
+// You should have received a copy of the CC0 Public Domain Dedication along
+// with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
+
+#include "siphash.h"
+
+inline static uint64_t
+u8to64_le (const unsigned char *p)
+{
+	return
+		(uint64_t) p[0]       |
+		(uint64_t) p[1] <<  8 |
+		(uint64_t) p[2] << 16 |
+		(uint64_t) p[3] << 24 |
+		(uint64_t) p[4] << 32 |
+		(uint64_t) p[5] << 40 |
+		(uint64_t) p[6] << 48 |
+		(uint64_t) p[7] << 56 ;
+}
+
+uint64_t
+siphash (const unsigned char key[16], const unsigned char *m, size_t len)
+{
+	uint64_t v0, v1, v2, v3;
+	uint64_t mi, k0, k1;
+	uint64_t last7;
+	size_t i, blocks;
+
+	k0 = u8to64_le (key + 0);
+	k1 = u8to64_le (key + 8);
+	v0 = k0 ^ 0x736f6d6570736575ull;
+	v1 = k1 ^ 0x646f72616e646f6dull;
+	v2 = k0 ^ 0x6c7967656e657261ull;
+	v3 = k1 ^ 0x7465646279746573ull;
+
+	last7 = (uint64_t) (len & 0xff) << 56;
+
+#define ROTL64(a,b) (((a)<<(b))|((a)>>(64-b)))
+
+#define COMPRESS                              \
+	v0 += v1; v2 += v3;                       \
+	v1 = ROTL64 (v1,13); v3 = ROTL64 (v3,16); \
+	v1 ^= v0; v3 ^= v2;                       \
+	v0 = ROTL64 (v0,32);                      \
+	v2 += v1; v0 += v3;                       \
+	v1 = ROTL64 (v1,17); v3 = ROTL64 (v3,21); \
+	v1 ^= v2; v3 ^= v0;                       \
+	v2 = ROTL64(v2,32);
+
+	for (i = 0, blocks = (len & ~(size_t) 7); i < blocks; i += 8)
+	{
+		mi = u8to64_le (m + i);
+		v3 ^= mi;
+		COMPRESS
+		COMPRESS
+		v0 ^= mi;
+	}
+
+	switch (len - blocks)
+	{
+	case 7: last7 |= (uint64_t) m[i + 6] << 48;
+	case 6: last7 |= (uint64_t) m[i + 5] << 40;
+	case 5: last7 |= (uint64_t) m[i + 4] << 32;
+	case 4: last7 |= (uint64_t) m[i + 3] << 24;
+	case 3: last7 |= (uint64_t) m[i + 2] << 16;
+	case 2: last7 |= (uint64_t) m[i + 1] <<  8;
+	case 1: last7 |= (uint64_t) m[i + 0]      ;
+	default:;
+	};
+	v3 ^= last7;
+	COMPRESS
+	COMPRESS
+	v0 ^= last7;
+	v2 ^= 0xff;
+	COMPRESS
+	COMPRESS
+	COMPRESS
+	COMPRESS
+
+	return v0 ^ v1 ^ v2 ^ v3;
+}
+
diff --git a/siphash.h b/siphash.h
new file mode 100644
index 0000000..dca7c42
--- /dev/null
+++ b/siphash.h
@@ -0,0 +1,10 @@
+#ifndef SIPHASH_H
+#define SIPHASH_H
+
+#include <stdint.h>
+#include <stdlib.h>
+
+uint64_t siphash (const unsigned char key[16],
+	const unsigned char *m, size_t len);
+
+#endif // SIPHASH_H
diff --git a/tests/liberty.c b/tests/liberty.c
new file mode 100644
index 0000000..8956ed0
--- /dev/null
+++ b/tests/liberty.c
@@ -0,0 +1,345 @@
+/*
+ * tests/liberty.c
+ *
+ * Copyright (c) 2015, Přemysl Janouch <p.janouch@gmail.com>
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#define PROGRAM_NAME "test"
+#define PROGRAM_VERSION "0"
+
+#include "../liberty.c"
+
+// --- Memory ------------------------------------------------------------------
+
+#define KILO 1024
+#define MEGA 1048576
+
+static void
+test_memory (void)
+{
+	void *m = xmalloc (MEGA);
+	memset (m, 0, MEGA);
+
+	void *n = xcalloc (KILO, KILO);
+	soft_assert (!memcmp (n, m, MEGA));
+
+	m = xrealloc (m, 1024);
+	n = xreallocarray (n, KILO, 1);
+	soft_assert (!memcmp (n, m, KILO));
+
+	free (m);
+	free (n);
+
+	char *s = xstrdup ("test");
+	char *t = xstrndup ("testing", 4);
+	soft_assert (!strcmp (s, t));
+
+	free (s);
+	free (t);
+}
+
+// --- Linked lists ------------------------------------------------------------
+
+struct my_link
+{
+	LIST_HEADER (struct my_link)
+	int n;
+};
+
+static struct my_link *
+make_link (int value)
+{
+	struct my_link *link = xcalloc (1, sizeof *link);
+	link->n = value;
+	return link;
+}
+
+static void
+check_linked_list (struct my_link *list, struct my_link **a, int n)
+{
+	// The linked list must contain items from the array, in that order
+	struct my_link *iter = list;
+	for (int i = 0; i < n; i++)
+	{
+		if (!a[i])
+			continue;
+
+		hard_assert (iter != NULL);
+		soft_assert (iter->n == i);
+		iter = iter->next;
+	}
+
+	// And nothing more
+	soft_assert (iter == NULL);
+}
+
+static void
+test_list (void)
+{
+	struct my_link *list = NULL;
+	struct my_link *a[10];
+
+	// Prepare a linked list
+	for (int i = N_ELEMENTS (a); i--; )
+	{
+		a[i] = make_link (i);
+		LIST_PREPEND (list, a[i]);
+	}
+
+	// Remove a few entries
+	LIST_UNLINK (list, a[0]); a[0] = NULL;
+	LIST_UNLINK (list, a[3]); a[3] = NULL;
+	LIST_UNLINK (list, a[4]); a[4] = NULL;
+	LIST_UNLINK (list, a[6]); a[6] = NULL;
+
+	// Prepend one more item
+	a[0] = make_link (0);
+	LIST_PREPEND (list, a[0]);
+
+	// Check the contents
+	check_linked_list (list, a, N_ELEMENTS (a));
+
+	// Destroy the linked list
+	LIST_FOR_EACH (struct my_link, iter, list)
+		free (iter);
+}
+
+static void
+test_list_with_tail (void)
+{
+	struct my_link *list = NULL;
+	struct my_link *tail = NULL;
+	struct my_link *a[10];
+
+	// Prepare a linked list
+	for (int i = 0; i < (int) N_ELEMENTS (a); i++)
+	{
+		a[i] = make_link (i);
+		LIST_APPEND_WITH_TAIL (list, tail, a[i]);
+	}
+
+	// Remove a few entries
+	LIST_UNLINK_WITH_TAIL (list, tail, a[0]); a[0] = NULL;
+	LIST_UNLINK_WITH_TAIL (list, tail, a[3]); a[3] = NULL;
+	LIST_UNLINK_WITH_TAIL (list, tail, a[4]); a[4] = NULL;
+	LIST_UNLINK_WITH_TAIL (list, tail, a[6]); a[6] = NULL;
+	LIST_UNLINK_WITH_TAIL (list, tail, a[9]); a[9] = NULL;
+
+	// Append one more item
+	a[9] = make_link (9);
+	LIST_APPEND_WITH_TAIL (list, tail, a[9]);
+
+	// Check the contents
+	check_linked_list (list, a, N_ELEMENTS (a));
+
+	// Destroy the linked list
+	LIST_FOR_EACH (struct my_link, iter, list)
+		free (iter);
+}
+
+// --- Strings -----------------------------------------------------------------
+
+static void
+test_str_vector (void)
+{
+	struct str_vector v;
+	str_vector_init (&v);
+
+	str_vector_add_owned (&v, xstrdup ("xkcd"));
+	str_vector_reset (&v);
+
+	const char *a[] =
+		{ "123", "456", "a", "bc", "def", "ghij", "klmno", "pqrstu" };
+
+	// Add the first two items via another vector
+	struct str_vector w;
+	str_vector_init (&w);
+	str_vector_add_args (&w, a[0], a[1], NULL);
+	str_vector_add_vector (&v, w.vector);
+	str_vector_free (&w);
+
+	// Add an item and delete it right after
+	str_vector_add (&v, "test");
+	str_vector_remove (&v, v.len - 1);
+
+	// Add the rest of the list properly
+	for (int i = 2; i < (int) N_ELEMENTS (a); i++)
+		str_vector_add (&v, a[i]);
+
+	// Check the contents
+	soft_assert (v.len == N_ELEMENTS (a));
+	for (int i = 0; i < (int) N_ELEMENTS (a); i++)
+		soft_assert (!strcmp (v.vector[i], a[i]));
+	soft_assert (v.vector[v.len] == NULL);
+
+	str_vector_free (&v);
+}
+
+static void
+test_str (void)
+{
+	uint8_t x[] = { 0x12, 0x34, 0x56, 0x78, 0x11, 0x22, 0x33, 0x44 };
+
+	struct str s;
+	str_init (&s);
+	str_ensure_space (&s, MEGA);
+	str_append_data (&s, x, sizeof x);
+	str_remove_slice (&s, 4, 4);
+	soft_assert (s.len == 4);
+
+	struct str t;
+	str_init (&t);
+	str_append_str (&t, &s);
+	str_append (&t, "abc");
+	str_append_c (&t, 'd');
+	str_append_printf (&t, "efg");
+
+	char *y = str_steal (&t);
+	soft_assert (!strcmp (y, "\x12\x34\x56\x78" "abcdefg"));
+	free (y);
+
+	str_reset (&s);
+	str_free (&s);
+}
+
+// --- Errors ------------------------------------------------------------------
+
+static void
+test_error (void)
+{
+	const char *m = "something fucked up";
+
+	struct error *e = NULL;
+	error_set (&e, "%s", m);
+
+	struct error *f = NULL;
+	error_propagate (&f, e);
+
+	soft_assert (f != NULL);
+	soft_assert (!strcmp (f->message, m));
+	error_free (f);
+}
+
+// --- Hash map ----------------------------------------------------------------
+
+static int
+tolower_ascii (int c)
+{
+	return c >= 'A' && c <= 'Z' ? c + ('a' - 'A') : c;
+}
+
+static size_t
+tolower_strxfrm (char *dest, const char *src, size_t n)
+{
+	size_t len = strlen (src);
+	while (n-- && (*dest++ = tolower_ascii (*src++)))
+		;
+	return len;
+}
+
+static void
+free_counter (void *data)
+{
+	int *counter = data;
+	if (!--*counter)
+		free (data);
+}
+
+static int *
+make_counter (void)
+{
+	int *counter = xmalloc (sizeof *counter);
+	*counter = 1;
+	return counter;
+}
+
+static int *
+ref_counter (int *counter)
+{
+	(*counter)++;
+	return counter;
+}
+
+static void
+test_str_map (void)
+{
+	// Put two reference counted objects in the map under case-insensitive keys
+	struct str_map m;
+	str_map_init (&m);
+	m.key_xfrm = tolower_strxfrm;
+	m.free = free_counter;
+
+	int *a = make_counter ();
+	int *b = make_counter ();
+
+	str_map_set (&m, "abc", ref_counter (a));
+	soft_assert (str_map_find (&m, "ABC") == a);
+	soft_assert (!str_map_find (&m, "DEFghi"));
+
+	str_map_set (&m, "defghi", ref_counter (b));
+	soft_assert (str_map_find (&m, "ABC") == a);
+	soft_assert (str_map_find (&m, "DEFghi") == b);
+
+	// Check that we can iterate over both of them
+	struct str_map_iter iter;
+	str_map_iter_init (&iter, &m);
+
+	bool met_a = false;
+	bool met_b = false;
+	void *iter_data;
+	while ((iter_data = str_map_iter_next (&iter)))
+	{
+		if (iter_data == a) { soft_assert (!met_a); met_a = true; }
+		if (iter_data == b) { soft_assert (!met_b); met_b = true; }
+		soft_assert (met_a || met_b);
+	}
+	soft_assert (met_a && met_b);
+
+	// Remove one of the keys
+	str_map_set (&m, "abc", NULL);
+	soft_assert (!str_map_find (&m, "ABC"));
+	soft_assert (str_map_find (&m, "DEFghi") == b);
+
+	str_map_free (&m);
+
+	// Check that the objects have been destroyed exactly once
+	soft_assert (*a == 1);
+	soft_assert (*b == 1);
+	free_counter (a);
+	free_counter (b);
+}
+
+// --- Main --------------------------------------------------------------------
+
+int
+main (int argc, char *argv[])
+{
+	struct test test;
+	test_init (&test, argc, argv);
+
+	test_add_simple (&test, "/memory",         NULL, test_memory);
+	test_add_simple (&test, "/list",           NULL, test_list);
+	test_add_simple (&test, "/list-with-tail", NULL, test_list_with_tail);
+	test_add_simple (&test, "/str-vector",     NULL, test_str_vector);
+	test_add_simple (&test, "/str",            NULL, test_str);
+	test_add_simple (&test, "/error",          NULL, test_error);
+	test_add_simple (&test, "/str-map",        NULL, test_str_map);
+
+	// TODO: write tests for the rest of the library
+
+	return test_run (&test);
+}