1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
|
/*
* iexec.c: run a program and restart on file change
*
* Copyright (c) 2017 - 2023, Přemysl Eric Janouch <p@janouch.name>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted.
*
* 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.
*
*/
#include "config.h"
#undef PROGRAM_NAME
#define PROGRAM_NAME "iexec"
#include "liberty/liberty.c"
// This can also work on BSD if someone puts in the effort to support kqueue
#include <sys/inotify.h>
static struct
{
pid_t child; ///< Watched child or 0
bool exits; ///< Don't restart child when it exits
bool respawn; ///< Respawn child ASAP
bool killing; ///< Waiting for child to die
int inotify_fd, inotify_wd;
}
g;
// Note that this program doesn't queue up file-based restarts
static void
handle_inotify_event (const struct inotify_event *e, const char *base)
{
if (e->wd != g.inotify_wd || strcmp (e->name, base))
return;
if (g.child)
{
print_debug ("file changed, killing child");
if (kill (g.child, SIGINT))
print_error ("kill: %s", strerror (errno));
g.killing = true;
}
else
{
print_debug ("file changed, respawning");
g.respawn = true;
}
}
static void
handle_file_change (const char *base)
{
char buf[4096];
ssize_t len = 0;
struct inotify_event *e = NULL;
while ((len = read (g.inotify_fd, buf, sizeof buf)) > 0)
for (char *ptr = buf; ptr < buf + len; ptr += sizeof *e + e->len)
handle_inotify_event ((e = (struct inotify_event *) buf), base);
}
static void
spawn (char *argv[])
{
if ((g.child = fork ()) == -1)
exit_fatal ("fork: %s", strerror (errno));
else if (g.child)
return;
// A linker can create spurious CLOSE_WRITEs, wait until it's executable
while (1)
{
execvp (argv[0], argv);
print_error ("execvp: %s", strerror (errno));
sleep (1);
}
}
static bool
check_child_death (void)
{
int status = 0;
if (waitpid (g.child, &status, WNOHANG) != g.child)
return true;
g.child = 0;
if (!g.killing)
{
print_debug ("child died on its own, not respawning");
return g.exits;
}
g.killing = false;
print_debug ("child died on request, respawning");
return g.respawn = true;
}
static void
sigchld_handler (int signum)
{
// We need to have this handler so that pselect() can return EINTR
(void) signum;
}
int
main (int argc, char *argv[])
{
const char *target = NULL;
static const struct opt opts[] =
{
{ 'f', "file", "PATH", 0, "watch this path rather than the program" },
{ 'e', "exits", NULL, 0, "allow the program to exit on its own" },
{ 'd', "debug", NULL, 0, "run in debug mode" },
{ 'h', "help", NULL, 0, "display this help and exit" },
{ 'V', "version", NULL, 0, "output version information and exit" },
{ 0, NULL, NULL, 0, NULL }
};
struct opt_handler oh = opt_handler_make (argc, argv, opts,
"PROGRAM [ARG...]", "Run a program and restart it when it changes.");
// We have to turn that off as it causes more trouble than what it's worth
cstr_set (&oh.opt_string, xstrdup_printf ("+%s", oh.opt_string));
int c;
while ((c = opt_handler_get (&oh)) != -1)
switch (c)
{
case 'f':
target = optarg;
break;
case 'e':
g.exits = true;
break;
case 'd':
g_debug_mode = true;
break;
case 'h':
opt_handler_usage (&oh, stdout);
exit (EXIT_SUCCESS);
case 'V':
printf (PROGRAM_NAME " " PROGRAM_VERSION "\n");
exit (EXIT_SUCCESS);
default:
print_error ("wrong options");
opt_handler_usage (&oh, stderr);
exit (EXIT_FAILURE);
}
if (argc == optind)
{
opt_handler_usage (&oh, stderr);
exit (EXIT_FAILURE);
}
opt_handler_free (&oh);
argc -= optind;
argv += optind;
if (!target)
target = argv[0];
(void) signal (SIGPIPE, SIG_IGN);
struct sigaction sa = { .sa_handler = sigchld_handler };
sigemptyset (&sa.sa_mask);
if (sigaction (SIGCHLD, &sa, NULL))
exit_fatal ("sigaction: %s", strerror (errno));
sigset_t chld, orig;
sigemptyset (&chld);
sigaddset (&chld, SIGCHLD);
if (sigprocmask (SIG_BLOCK, &chld, &orig))
exit_fatal ("sigprocmask: %s", strerror (errno));
char *path = NULL;
char *dir = dirname ((path = xstrdup (target)));
if ((g.inotify_fd = inotify_init1 (IN_NONBLOCK)) < 0)
exit_fatal ("inotify_init1: %s", strerror (errno));
if ((g.inotify_wd = inotify_add_watch (g.inotify_fd,
dir, IN_MOVED_TO | IN_CLOSE_WRITE)) < 0)
exit_fatal ("inotify_add_watch: %s", strerror (errno));
free (path);
char *base = basename ((path = xstrdup (target)));
g.respawn = true;
do
{
if (g.respawn)
{
spawn (argv);
g.respawn = false;
}
fd_set r; FD_SET (g.inotify_fd, &r);
(void) pselect (g.inotify_fd + 1, &r, NULL, NULL, NULL, &orig);
handle_file_change (base);
}
while (check_child_death ());
free (path);
xclose (g.inotify_fd);
return EXIT_SUCCESS;
}
|
