fread does not return negative on error
[git] / run-command.c
1 #include "cache.h"
2 #include "run-command.h"
3 #include "exec_cmd.h"
4
5 static inline void close_pair(int fd[2])
6 {
7         close(fd[0]);
8         close(fd[1]);
9 }
10
11 static inline void dup_devnull(int to)
12 {
13         int fd = open("/dev/null", O_RDWR);
14         dup2(fd, to);
15         close(fd);
16 }
17
18 int start_command(struct child_process *cmd)
19 {
20         int need_in, need_out, need_err;
21         int fdin[2], fdout[2], fderr[2];
22
23         /*
24          * In case of errors we must keep the promise to close FDs
25          * that have been passed in via ->in and ->out.
26          */
27
28         need_in = !cmd->no_stdin && cmd->in < 0;
29         if (need_in) {
30                 if (pipe(fdin) < 0) {
31                         if (cmd->out > 0)
32                                 close(cmd->out);
33                         return -ERR_RUN_COMMAND_PIPE;
34                 }
35                 cmd->in = fdin[1];
36         }
37
38         need_out = !cmd->no_stdout
39                 && !cmd->stdout_to_stderr
40                 && cmd->out < 0;
41         if (need_out) {
42                 if (pipe(fdout) < 0) {
43                         if (need_in)
44                                 close_pair(fdin);
45                         else if (cmd->in)
46                                 close(cmd->in);
47                         return -ERR_RUN_COMMAND_PIPE;
48                 }
49                 cmd->out = fdout[0];
50         }
51
52         need_err = !cmd->no_stderr && cmd->err < 0;
53         if (need_err) {
54                 if (pipe(fderr) < 0) {
55                         if (need_in)
56                                 close_pair(fdin);
57                         else if (cmd->in)
58                                 close(cmd->in);
59                         if (need_out)
60                                 close_pair(fdout);
61                         else if (cmd->out)
62                                 close(cmd->out);
63                         return -ERR_RUN_COMMAND_PIPE;
64                 }
65                 cmd->err = fderr[0];
66         }
67
68         trace_argv_printf(cmd->argv, "trace: run_command:");
69
70 #ifndef __MINGW32__
71         fflush(NULL);
72         cmd->pid = fork();
73         if (!cmd->pid) {
74                 if (cmd->no_stdin)
75                         dup_devnull(0);
76                 else if (need_in) {
77                         dup2(fdin[0], 0);
78                         close_pair(fdin);
79                 } else if (cmd->in) {
80                         dup2(cmd->in, 0);
81                         close(cmd->in);
82                 }
83
84                 if (cmd->no_stderr)
85                         dup_devnull(2);
86                 else if (need_err) {
87                         dup2(fderr[1], 2);
88                         close_pair(fderr);
89                 }
90
91                 if (cmd->no_stdout)
92                         dup_devnull(1);
93                 else if (cmd->stdout_to_stderr)
94                         dup2(2, 1);
95                 else if (need_out) {
96                         dup2(fdout[1], 1);
97                         close_pair(fdout);
98                 } else if (cmd->out > 1) {
99                         dup2(cmd->out, 1);
100                         close(cmd->out);
101                 }
102
103                 if (cmd->dir && chdir(cmd->dir))
104                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
105                             cmd->dir, strerror(errno));
106                 if (cmd->env) {
107                         for (; *cmd->env; cmd->env++) {
108                                 if (strchr(*cmd->env, '='))
109                                         putenv((char *)*cmd->env);
110                                 else
111                                         unsetenv(*cmd->env);
112                         }
113                 }
114                 if (cmd->preexec_cb)
115                         cmd->preexec_cb();
116                 if (cmd->git_cmd) {
117                         execv_git_cmd(cmd->argv);
118                 } else {
119                         execvp(cmd->argv[0], (char *const*) cmd->argv);
120                 }
121                 trace_printf("trace: exec '%s' failed: %s\n", cmd->argv[0],
122                                 strerror(errno));
123                 exit(127);
124         }
125 #else
126         int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
127         const char **sargv = cmd->argv;
128         char **env = environ;
129
130         if (cmd->no_stdin) {
131                 s0 = dup(0);
132                 dup_devnull(0);
133         } else if (need_in) {
134                 s0 = dup(0);
135                 dup2(fdin[0], 0);
136         } else if (cmd->in) {
137                 s0 = dup(0);
138                 dup2(cmd->in, 0);
139         }
140
141         if (cmd->no_stderr) {
142                 s2 = dup(2);
143                 dup_devnull(2);
144         } else if (need_err) {
145                 s2 = dup(2);
146                 dup2(fderr[1], 2);
147         }
148
149         if (cmd->no_stdout) {
150                 s1 = dup(1);
151                 dup_devnull(1);
152         } else if (cmd->stdout_to_stderr) {
153                 s1 = dup(1);
154                 dup2(2, 1);
155         } else if (need_out) {
156                 s1 = dup(1);
157                 dup2(fdout[1], 1);
158         } else if (cmd->out > 1) {
159                 s1 = dup(1);
160                 dup2(cmd->out, 1);
161         }
162
163         if (cmd->dir)
164                 die("chdir in start_command() not implemented");
165         if (cmd->env) {
166                 env = copy_environ();
167                 for (; *cmd->env; cmd->env++)
168                         env = env_setenv(env, *cmd->env);
169         }
170
171         if (cmd->git_cmd) {
172                 cmd->argv = prepare_git_cmd(cmd->argv);
173         }
174
175         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
176
177         if (cmd->env)
178                 free_environ(env);
179         if (cmd->git_cmd)
180                 free(cmd->argv);
181
182         cmd->argv = sargv;
183         if (s0 >= 0)
184                 dup2(s0, 0), close(s0);
185         if (s1 >= 0)
186                 dup2(s1, 1), close(s1);
187         if (s2 >= 0)
188                 dup2(s2, 2), close(s2);
189 #endif
190
191         if (cmd->pid < 0) {
192                 int err = errno;
193                 if (need_in)
194                         close_pair(fdin);
195                 else if (cmd->in)
196                         close(cmd->in);
197                 if (need_out)
198                         close_pair(fdout);
199                 else if (cmd->out)
200                         close(cmd->out);
201                 if (need_err)
202                         close_pair(fderr);
203                 return err == ENOENT ?
204                         -ERR_RUN_COMMAND_EXEC :
205                         -ERR_RUN_COMMAND_FORK;
206         }
207
208         if (need_in)
209                 close(fdin[0]);
210         else if (cmd->in)
211                 close(cmd->in);
212
213         if (need_out)
214                 close(fdout[1]);
215         else if (cmd->out)
216                 close(cmd->out);
217
218         if (need_err)
219                 close(fderr[1]);
220
221         return 0;
222 }
223
224 static int wait_or_whine(pid_t pid)
225 {
226         for (;;) {
227                 int status, code;
228                 pid_t waiting = waitpid(pid, &status, 0);
229
230                 if (waiting < 0) {
231                         if (errno == EINTR)
232                                 continue;
233                         error("waitpid failed (%s)", strerror(errno));
234                         return -ERR_RUN_COMMAND_WAITPID;
235                 }
236                 if (waiting != pid)
237                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
238                 if (WIFSIGNALED(status))
239                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
240
241                 if (!WIFEXITED(status))
242                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
243                 code = WEXITSTATUS(status);
244                 switch (code) {
245                 case 127:
246                         return -ERR_RUN_COMMAND_EXEC;
247                 case 0:
248                         return 0;
249                 default:
250                         return -code;
251                 }
252         }
253 }
254
255 int finish_command(struct child_process *cmd)
256 {
257         return wait_or_whine(cmd->pid);
258 }
259
260 int run_command(struct child_process *cmd)
261 {
262         int code = start_command(cmd);
263         if (code)
264                 return code;
265         return finish_command(cmd);
266 }
267
268 static void prepare_run_command_v_opt(struct child_process *cmd,
269                                       const char **argv,
270                                       int opt)
271 {
272         memset(cmd, 0, sizeof(*cmd));
273         cmd->argv = argv;
274         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
275         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
276         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
277 }
278
279 int run_command_v_opt(const char **argv, int opt)
280 {
281         struct child_process cmd;
282         prepare_run_command_v_opt(&cmd, argv, opt);
283         return run_command(&cmd);
284 }
285
286 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
287 {
288         struct child_process cmd;
289         prepare_run_command_v_opt(&cmd, argv, opt);
290         cmd.dir = dir;
291         cmd.env = env;
292         return run_command(&cmd);
293 }
294
295 #ifdef __MINGW32__
296 static __stdcall unsigned run_thread(void *data)
297 {
298         struct async *async = data;
299         return async->proc(async->fd_for_proc, async->data);
300 }
301 #endif
302
303 int start_async(struct async *async)
304 {
305         int pipe_out[2];
306
307         if (pipe(pipe_out) < 0)
308                 return error("cannot create pipe: %s", strerror(errno));
309         async->out = pipe_out[0];
310
311 #ifndef __MINGW32__
312         /* Flush stdio before fork() to avoid cloning buffers */
313         fflush(NULL);
314
315         async->pid = fork();
316         if (async->pid < 0) {
317                 error("fork (async) failed: %s", strerror(errno));
318                 close_pair(pipe_out);
319                 return -1;
320         }
321         if (!async->pid) {
322                 close(pipe_out[0]);
323                 exit(!!async->proc(pipe_out[1], async->data));
324         }
325         close(pipe_out[1]);
326 #else
327         async->fd_for_proc = pipe_out[1];
328         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
329         if (!async->tid) {
330                 error("cannot create thread: %s", strerror(errno));
331                 close_pair(pipe_out);
332                 return -1;
333         }
334 #endif
335         return 0;
336 }
337
338 int finish_async(struct async *async)
339 {
340 #ifndef __MINGW32__
341         int ret = 0;
342
343         if (wait_or_whine(async->pid))
344                 ret = error("waitpid (async) failed");
345 #else
346         DWORD ret = 0;
347         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
348                 ret = error("waiting for thread failed: %lu", GetLastError());
349         else if (!GetExitCodeThread(async->tid, &ret))
350                 ret = error("cannot get thread exit code: %lu", GetLastError());
351         CloseHandle(async->tid);
352 #endif
353         return ret;
354 }
355
356 int run_hook(const char *index_file, const char *name, ...)
357 {
358         struct child_process hook;
359         const char **argv = NULL, *env[2];
360         char index[PATH_MAX];
361         va_list args;
362         int ret;
363         size_t i = 0, alloc = 0;
364
365         if (access(git_path("hooks/%s", name), X_OK) < 0)
366                 return 0;
367
368         va_start(args, name);
369         ALLOC_GROW(argv, i + 1, alloc);
370         argv[i++] = git_path("hooks/%s", name);
371         while (argv[i-1]) {
372                 ALLOC_GROW(argv, i + 1, alloc);
373                 argv[i++] = va_arg(args, const char *);
374         }
375         va_end(args);
376
377         memset(&hook, 0, sizeof(hook));
378         hook.argv = argv;
379         hook.no_stdin = 1;
380         hook.stdout_to_stderr = 1;
381         if (index_file) {
382                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
383                 env[0] = index;
384                 env[1] = NULL;
385                 hook.env = env;
386         }
387
388         ret = start_command(&hook);
389         free(argv);
390         if (ret) {
391                 warning("Could not spawn %s", argv[0]);
392                 return ret;
393         }
394         ret = finish_command(&hook);
395         if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
396                 warning("%s exited due to uncaught signal", argv[0]);
397
398         return ret;
399 }