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