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         cmd->pid = fork();
  72         if (!cmd->pid) {
  73                 if (cmd->no_stdin)
  74                         dup_devnull(0);
  75                 else if (need_in) {
  76                         dup2(fdin[0], 0);
  77                         close_pair(fdin);
  78                 } else if (cmd->in) {
  79                         dup2(cmd->in, 0);
  80                         close(cmd->in);
  81                 }
  82
  83                 if (cmd->no_stderr)
  84                         dup_devnull(2);
  85                 else if (need_err) {
  86                         dup2(fderr[1], 2);
  87                         close_pair(fderr);
  88                 }
  89
  90                 if (cmd->no_stdout)
  91                         dup_devnull(1);
  92                 else if (cmd->stdout_to_stderr)
  93                         dup2(2, 1);
  94                 else if (need_out) {
  95                         dup2(fdout[1], 1);
  96                         close_pair(fdout);
  97                 } else if (cmd->out > 1) {
  98                         dup2(cmd->out, 1);
  99                         close(cmd->out);
 100                 }
 101
 102                 if (cmd->dir && chdir(cmd->dir))
 103                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
 104                             cmd->dir, strerror(errno));
 105                 if (cmd->env) {
 106                         for (; *cmd->env; cmd->env++) {
 107                                 if (strchr(*cmd->env, '='))
 108                                         putenv((char*)*cmd->env);
 109                                 else
 110                                         unsetenv(*cmd->env);
 111                         }
 112                 }
 113                 if (cmd->preexec_cb)
 114                         cmd->preexec_cb();
 115                 if (cmd->git_cmd) {
 116                         execv_git_cmd(cmd->argv);
 117                 } else {
 118                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 119                 }
 120                 die("exec %s failed.", cmd->argv[0]);
 121         }
 122 #else
 123         int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
 124         const char **sargv = cmd->argv;
 125         char **env = environ;
 126
 127         if (cmd->no_stdin) {
 128                 s0 = dup(0);
 129                 dup_devnull(0);
 130         } else if (need_in) {
 131                 s0 = dup(0);
 132                 dup2(fdin[0], 0);
 133         } else if (cmd->in) {
 134                 s0 = dup(0);
 135                 dup2(cmd->in, 0);
 136         }
 137
 138         if (cmd->no_stderr) {
 139                 s2 = dup(2);
 140                 dup_devnull(2);
 141         } else if (need_err) {
 142                 s2 = dup(2);
 143                 dup2(fderr[1], 2);
 144         }
 145
 146         if (cmd->no_stdout) {
 147                 s1 = dup(1);
 148                 dup_devnull(1);
 149         } else if (cmd->stdout_to_stderr) {
 150                 s1 = dup(1);
 151                 dup2(2, 1);
 152         } else if (need_out) {
 153                 s1 = dup(1);
 154                 dup2(fdout[1], 1);
 155         } else if (cmd->out > 1) {
 156                 s1 = dup(1);
 157                 dup2(cmd->out, 1);
 158         }
 159
 160         if (cmd->dir)
 161                 die("chdir in start_command() not implemented");
 162         if (cmd->env) {
 163                 env = copy_environ();
 164                 for (; *cmd->env; cmd->env++)
 165                         env = env_setenv(env, *cmd->env);
 166         }
 167
 168         if (cmd->git_cmd) {
 169                 cmd->argv = prepare_git_cmd(cmd->argv);
 170         }
 171
 172         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
 173
 174         if (cmd->env)
 175                 free_environ(env);
 176         if (cmd->git_cmd)
 177                 free(cmd->argv);
 178
 179         cmd->argv = sargv;
 180         if (s0 >= 0)
 181                 dup2(s0, 0), close(s0);
 182         if (s1 >= 0)
 183                 dup2(s1, 1), close(s1);
 184         if (s2 >= 0)
 185                 dup2(s2, 2), close(s2);
 186 #endif
 187
 188         if (cmd->pid < 0) {
 189                 if (need_in)
 190                         close_pair(fdin);
 191                 else if (cmd->in)
 192                         close(cmd->in);
 193                 if (need_out)
 194                         close_pair(fdout);
 195                 else if (cmd->out)
 196                         close(cmd->out);
 197                 if (need_err)
 198                         close_pair(fderr);
 199                 return -ERR_RUN_COMMAND_FORK;
 200         }
 201
 202         if (need_in)
 203                 close(fdin[0]);
 204         else if (cmd->in)
 205                 close(cmd->in);
 206
 207         if (need_out)
 208                 close(fdout[1]);
 209         else if (cmd->out)
 210                 close(cmd->out);
 211
 212         if (need_err)
 213                 close(fderr[1]);
 214
 215         return 0;
 216 }
 217
 218 static int wait_or_whine(pid_t pid)
 219 {
 220         for (;;) {
 221                 int status, code;
 222                 pid_t waiting = waitpid(pid, &status, 0);
 223
 224                 if (waiting < 0) {
 225                         if (errno == EINTR)
 226                                 continue;
 227                         error("waitpid failed (%s)", strerror(errno));
 228                         return -ERR_RUN_COMMAND_WAITPID;
 229                 }
 230                 if (waiting != pid)
 231                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 232                 if (WIFSIGNALED(status))
 233                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 234
 235                 if (!WIFEXITED(status))
 236                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 237                 code = WEXITSTATUS(status);
 238                 if (code)
 239                         return -code;
 240                 return 0;
 241         }
 242 }
 243
 244 int finish_command(struct child_process *cmd)
 245 {
 246         return wait_or_whine(cmd->pid);
 247 }
 248
 249 int run_command(struct child_process *cmd)
 250 {
 251         int code = start_command(cmd);
 252         if (code)
 253                 return code;
 254         return finish_command(cmd);
 255 }
 256
 257 static void prepare_run_command_v_opt(struct child_process *cmd,
 258                                       const char **argv,
 259                                       int opt)
 260 {
 261         memset(cmd, 0, sizeof(*cmd));
 262         cmd->argv = argv;
 263         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 264         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 265         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 266 }
 267
 268 int run_command_v_opt(const char **argv, int opt)
 269 {
 270         struct child_process cmd;
 271         prepare_run_command_v_opt(&cmd, argv, opt);
 272         return run_command(&cmd);
 273 }
 274
 275 int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
 276 {
 277         struct child_process cmd;
 278         prepare_run_command_v_opt(&cmd, argv, opt);
 279         cmd.dir = dir;
 280         return run_command(&cmd);
 281 }
 282
 283 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 284 {
 285         struct child_process cmd;
 286         prepare_run_command_v_opt(&cmd, argv, opt);
 287         cmd.dir = dir;
 288         cmd.env = env;
 289         return run_command(&cmd);
 290 }
 291
 292 #ifdef __MINGW32__
 293 static __stdcall unsigned run_thread(void *data)
 294 {
 295         struct async *async = data;
 296         return async->proc(async->fd_for_proc, async->data);
 297 }
 298 #endif
 299
 300 int start_async(struct async *async)
 301 {
 302         int pipe_out[2];
 303
 304         if (pipe(pipe_out) < 0)
 305                 return error("cannot create pipe: %s", strerror(errno));
 306         async->out = pipe_out[0];
 307
 308 #ifndef __MINGW32__
 309         /* Flush stdio before fork() to avoid cloning buffers */
 310         fflush(NULL);
 311
 312         async->pid = fork();
 313         if (async->pid < 0) {
 314                 error("fork (async) failed: %s", strerror(errno));
 315                 close_pair(pipe_out);
 316                 return -1;
 317         }
 318         if (!async->pid) {
 319                 close(pipe_out[0]);
 320                 exit(!!async->proc(pipe_out[1], async->data));
 321         }
 322         close(pipe_out[1]);
 323 #else
 324         async->fd_for_proc = pipe_out[1];
 325         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 326         if (!async->tid) {
 327                 error("cannot create thread: %s", strerror(errno));
 328                 close_pair(pipe_out);
 329                 return -1;
 330         }
 331 #endif
 332         return 0;
 333 }
 334
 335 int finish_async(struct async *async)
 336 {
 337 #ifndef __MINGW32__
 338         int ret = 0;
 339
 340         if (wait_or_whine(async->pid))
 341                 ret = error("waitpid (async) failed");
 342 #else
 343         DWORD ret = 0;
 344         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 345                 ret = error("waiting for thread failed: %lu", GetLastError());
 346         else if (!GetExitCodeThread(async->tid, &ret))
 347                 ret = error("cannot get thread exit code: %lu", GetLastError());
 348         CloseHandle(async->tid);
 349 #endif
 350         return ret;
 351 }