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 #ifndef __MINGW32__
  69         cmd->pid = fork();
  70         if (!cmd->pid) {
  71                 if (cmd->no_stdin)
  72                         dup_devnull(0);
  73                 else if (need_in) {
  74                         dup2(fdin[0], 0);
  75                         close_pair(fdin);
  76                 } else if (cmd->in) {
  77                         dup2(cmd->in, 0);
  78                         close(cmd->in);
  79                 }
  80
  81                 if (cmd->no_stderr)
  82                         dup_devnull(2);
  83                 else if (need_err) {
  84                         dup2(fderr[1], 2);
  85                         close_pair(fderr);
  86                 }
  87
  88                 if (cmd->no_stdout)
  89                         dup_devnull(1);
  90                 else if (cmd->stdout_to_stderr)
  91                         dup2(2, 1);
  92                 else if (need_out) {
  93                         dup2(fdout[1], 1);
  94                         close_pair(fdout);
  95                 } else if (cmd->out > 1) {
  96                         dup2(cmd->out, 1);
  97                         close(cmd->out);
  98                 }
  99
 100                 if (cmd->dir && chdir(cmd->dir))
 101                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
 102                             cmd->dir, strerror(errno));
 103                 if (cmd->env) {
 104                         for (; *cmd->env; cmd->env++) {
 105                                 if (strchr(*cmd->env, '='))
 106                                         putenv((char*)*cmd->env);
 107                                 else
 108                                         unsetenv(*cmd->env);
 109                         }
 110                 }
 111                 if (cmd->git_cmd) {
 112                         execv_git_cmd(cmd->argv);
 113                 } else {
 114                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 115                 }
 116                 die("exec %s failed.", cmd->argv[0]);
 117         }
 118 #else
 119         int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
 120         const char *sargv0 = cmd->argv[0];
 121         char **env = environ;
 122         struct strbuf git_cmd;
 123
 124         if (cmd->no_stdin) {
 125                 s0 = dup(0);
 126                 dup_devnull(0);
 127         } else if (need_in) {
 128                 s0 = dup(0);
 129                 dup2(fdin[0], 0);
 130         } else if (cmd->in) {
 131                 s0 = dup(0);
 132                 dup2(cmd->in, 0);
 133         }
 134
 135         if (cmd->no_stderr) {
 136                 s2 = dup(2);
 137                 dup_devnull(2);
 138         } else if (need_err) {
 139                 s2 = dup(2);
 140                 dup2(fderr[1], 2);
 141         }
 142
 143         if (cmd->no_stdout) {
 144                 s1 = dup(1);
 145                 dup_devnull(1);
 146         } else if (cmd->stdout_to_stderr) {
 147                 s1 = dup(1);
 148                 dup2(2, 1);
 149         } else if (need_out) {
 150                 s1 = dup(1);
 151                 dup2(fdout[1], 1);
 152         } else if (cmd->out > 1) {
 153                 s1 = dup(1);
 154                 dup2(cmd->out, 1);
 155         }
 156
 157         if (cmd->dir)
 158                 die("chdir in start_command() not implemented");
 159         if (cmd->env) {
 160                 env = copy_environ();
 161                 for (; *cmd->env; cmd->env++)
 162                         env = env_setenv(env, *cmd->env);
 163         }
 164
 165         if (cmd->git_cmd) {
 166                 strbuf_init(&git_cmd, 0);
 167                 strbuf_addf(&git_cmd, "git-%s", cmd->argv[0]);
 168                 cmd->argv[0] = git_cmd.buf;
 169         }
 170
 171         cmd->pid = spawnvpe(_P_NOWAIT, cmd->argv[0], cmd->argv, (const char **)env);
 172
 173         if (cmd->env)
 174                 free_environ(env);
 175         if (cmd->git_cmd)
 176                 strbuf_release(&git_cmd);
 177
 178         cmd->argv[0] = sargv0;
 179         if (s0 >= 0)
 180                 dup2(s0, 0), close(s0);
 181         if (s1 >= 0)
 182                 dup2(s1, 1), close(s1);
 183         if (s2 >= 0)
 184                 dup2(s2, 2), close(s2);
 185 #endif
 186
 187         if (cmd->pid < 0) {
 188                 if (need_in)
 189                         close_pair(fdin);
 190                 else if (cmd->in)
 191                         close(cmd->in);
 192                 if (need_out)
 193                         close_pair(fdout);
 194                 else if (cmd->out)
 195                         close(cmd->out);
 196                 if (need_err)
 197                         close_pair(fderr);
 198                 return -ERR_RUN_COMMAND_FORK;
 199         }
 200
 201         if (need_in)
 202                 close(fdin[0]);
 203         else if (cmd->in)
 204                 close(cmd->in);
 205
 206         if (need_out)
 207                 close(fdout[1]);
 208         else if (cmd->out)
 209                 close(cmd->out);
 210
 211         if (need_err)
 212                 close(fderr[1]);
 213
 214         return 0;
 215 }
 216
 217 static int wait_or_whine(pid_t pid)
 218 {
 219         for (;;) {
 220                 int status, code;
 221                 pid_t waiting = waitpid(pid, &status, 0);
 222
 223                 if (waiting < 0) {
 224                         if (errno == EINTR)
 225                                 continue;
 226                         error("waitpid failed (%s)", strerror(errno));
 227                         return -ERR_RUN_COMMAND_WAITPID;
 228                 }
 229                 if (waiting != pid)
 230                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 231                 if (WIFSIGNALED(status))
 232                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 233
 234                 if (!WIFEXITED(status))
 235                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 236                 code = WEXITSTATUS(status);
 237                 if (code)
 238                         return -code;
 239                 return 0;
 240         }
 241 }
 242
 243 int finish_command(struct child_process *cmd)
 244 {
 245         return wait_or_whine(cmd->pid);
 246 }
 247
 248 int run_command(struct child_process *cmd)
 249 {
 250         int code = start_command(cmd);
 251         if (code)
 252                 return code;
 253         return finish_command(cmd);
 254 }
 255
 256 static void prepare_run_command_v_opt(struct child_process *cmd,
 257                                       const char **argv,
 258                                       int opt)
 259 {
 260         memset(cmd, 0, sizeof(*cmd));
 261         cmd->argv = argv;
 262         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 263         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 264         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 265 }
 266
 267 int run_command_v_opt(const char **argv, int opt)
 268 {
 269         struct child_process cmd;
 270         prepare_run_command_v_opt(&cmd, argv, opt);
 271         return run_command(&cmd);
 272 }
 273
 274 int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
 275 {
 276         struct child_process cmd;
 277         prepare_run_command_v_opt(&cmd, argv, opt);
 278         cmd.dir = dir;
 279         return run_command(&cmd);
 280 }
 281
 282 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 283 {
 284         struct child_process cmd;
 285         prepare_run_command_v_opt(&cmd, argv, opt);
 286         cmd.dir = dir;
 287         cmd.env = env;
 288         return run_command(&cmd);
 289 }
 290
 291 #ifdef __MINGW32__
 292 static __stdcall unsigned run_thread(void *data)
 293 {
 294         struct async *async = data;
 295         return async->proc(async->fd_for_proc, async->data);
 296 }
 297 #endif
 298
 299 int start_async(struct async *async)
 300 {
 301         int pipe_out[2];
 302
 303         if (pipe(pipe_out) < 0)
 304                 return error("cannot create pipe: %s", strerror(errno));
 305         async->out = pipe_out[0];
 306
 307 #ifndef __MINGW32__
 308         async->pid = fork();
 309         if (async->pid < 0) {
 310                 error("fork (async) failed: %s", strerror(errno));
 311                 close_pair(pipe_out);
 312                 return -1;
 313         }
 314         if (!async->pid) {
 315                 close(pipe_out[0]);
 316                 exit(!!async->proc(pipe_out[1], async->data));
 317         }
 318         close(pipe_out[1]);
 319 #else
 320         async->fd_for_proc = pipe_out[1];
 321         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 322         if (!async->tid) {
 323                 error("cannot create thread: %s", strerror(errno));
 324                 close_pair(pipe_out);
 325                 return -1;
 326         }
 327 #endif
 328         return 0;
 329 }
 330
 331 int finish_async(struct async *async)
 332 {
 333 #ifndef __MINGW32__
 334         int ret = 0;
 335
 336         if (wait_or_whine(async->pid))
 337                 ret = error("waitpid (async) failed");
 338 #else
 339         DWORD ret = 0;
 340         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 341                 ret = error("waiting for thread failed: %lu", GetLastError());
 342         else if (!GetExitCodeThread(async->tid, &ret))
 343                 ret = error("cannot get thread exit code: %lu", GetLastError());
 344         CloseHandle(async->tid);
 345 #endif
 346         return ret;
 347 }