summaryrefslogtreecommitdiff
path: root/utils.c
diff options
context:
space:
mode:
authorPřemysl Janouch <p.janouch@gmail.com>2015-02-22 10:54:49 +0100
committerPřemysl Janouch <p.janouch@gmail.com>2015-02-22 20:06:10 +0100
commit66cf41f89ff8e33413b63a351c05e65b98284b7a (patch)
tree15f344eaee3d693aa519b863fe44fd642820495d /utils.c
parent0f2a66e7b0a00af827c26db0a063c01bec65d0a6 (diff)
downloadjson-rpc-shell-66cf41f89ff8e33413b63a351c05e65b98284b7a.tar.gz
json-rpc-shell-66cf41f89ff8e33413b63a351c05e65b98284b7a.tar.xz
json-rpc-shell-66cf41f89ff8e33413b63a351c05e65b98284b7a.zip
Rewrite to use utils.c from ponymap
I'm starting to get tired of repeatingly doing this.
Diffstat (limited to 'utils.c')
-rw-r--r--utils.c1168
1 files changed, 1168 insertions, 0 deletions
diff --git a/utils.c b/utils.c
new file mode 100644
index 0000000..00772f7
--- /dev/null
+++ b/utils.c
@@ -0,0 +1,1168 @@
+/*
+ * utils.c: utilities
+ *
+ * Copyright (c) 2014, 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 <stdlib.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+#include <ctype.h>
+#include <locale.h>
+#include <errno.h>
+
+#include <unistd.h>
+#include <sys/stat.h>
+#include <libgen.h>
+#include <iconv.h>
+
+#include <getopt.h>
+#include "siphash.h"
+
+#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)
+
+// --- Logging -----------------------------------------------------------------
+
+static void
+log_message_stdio (const char *quote, const char *fmt, va_list ap)
+{
+ FILE *stream = stderr;
+
+ fputs (quote, stream);
+ vfprintf (stream, fmt, ap);
+ fputs ("\n", stream);
+}
+
+static void
+log_message (const char *quote, const char *fmt, ...) ATTRIBUTE_PRINTF (2, 3);
+
+static void
+log_message (const char *quote, const char *fmt, ...)
+{
+ va_list ap;
+ va_start (ap, fmt);
+ log_message_stdio (quote, fmt, ap);
+ va_end (ap);
+}
+
+// `fatal' is reserved for unexpected failures that would harm further operation
+
+// TODO: colors (probably copy over from stracepkg)
+#define print_fatal(...) log_message ("fatal: ", __VA_ARGS__)
+#define print_error(...) log_message ("error: ", __VA_ARGS__)
+#define print_warning(...) log_message ("warning: ", __VA_ARGS__)
+#define print_status(...) log_message ("-- ", __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
+
+#define print_debug(...) \
+ BLOCK_START \
+ if (g_debug_mode) \
+ log_message ("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) \
+ struct type *next; \
+ struct 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
+
+// --- 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_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));
+}
+
+// --- 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
+};
+
+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;
+}
+
+// --- 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);
+}
+
+// --- String hash map ---------------------------------------------------------
+
+// The most basic <string, managed pointer> map (or associative array).
+
+struct str_map_link
+{
+ LIST_HEADER (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);
+};
+
+#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 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);
+}
+
+// --- 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 *xstrdup_printf (const char *format, ...) ATTRIBUTE_PRINTF (1, 2);
+
+static char *
+xstrdup_printf (const char *format, ...)
+{
+ va_list ap;
+ va_start (ap, format);
+ int size = vsnprintf (NULL, 0, format, ap);
+ va_end (ap);
+ if (size < 0)
+ return NULL;
+
+ char buf[size + 1];
+ va_start (ap, format);
+ size = vsnprintf (buf, sizeof buf, format, ap);
+ va_end (ap);
+ if (size < 0)
+ return NULL;
+
+ return xstrdup (buf);
+}
+
+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
+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;
+}
+
+// --- 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);
+}