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