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         cmd->pid = fork();
  69         if (cmd->pid < 0) {
  70                 if (need_in)
  71                         close_pair(fdin);
  72                 else if (cmd->in)
  73                         close(cmd->in);
  74                 if (need_out)
  75                         close_pair(fdout);
  76                 else if (cmd->out)
  77                         close(cmd->out);
  78                 if (need_err)
  79                         close_pair(fderr);
  80                 return -ERR_RUN_COMMAND_FORK;
  81         }
  82
  83         if (!cmd->pid) {
  84                 if (cmd->no_stdin)
  85                         dup_devnull(0);
  86                 else if (need_in) {
  87                         dup2(fdin[0], 0);
  88                         close_pair(fdin);
  89                 } else if (cmd->in) {
  90                         dup2(cmd->in, 0);
  91                         close(cmd->in);
  92                 }
  93
  94                 if (cmd->no_stdout)
  95                         dup_devnull(1);
  96                 else if (cmd->stdout_to_stderr)
  97                         dup2(2, 1);
  98                 else if (need_out) {
  99                         dup2(fdout[1], 1);
 100                         close_pair(fdout);
 101                 } else if (cmd->out > 1) {
 102                         dup2(cmd->out, 1);
 103                         close(cmd->out);
 104                 }
 105
 106                 if (cmd->no_stderr)
 107                         dup_devnull(2);
 108                 else if (need_err) {
 109                         dup2(fderr[1], 2);
 110                         close_pair(fderr);
 111                 }
 112
 113                 if (cmd->dir && chdir(cmd->dir))
 114                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
 115                             cmd->dir, strerror(errno));
 116                 if (cmd->env) {
 117                         for (; *cmd->env; cmd->env++) {
 118                                 if (strchr(*cmd->env, '='))
 119                                         putenv((char*)*cmd->env);
 120                                 else
 121                                         unsetenv(*cmd->env);
 122                         }
 123                 }
 124                 if (cmd->git_cmd) {
 125                         execv_git_cmd(cmd->argv);
 126                 } else {
 127                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 128                 }
 129                 die("exec %s failed.", cmd->argv[0]);
 130         }
 131
 132         if (need_in)
 133                 close(fdin[0]);
 134         else if (cmd->in)
 135                 close(cmd->in);
 136
 137         if (need_out)
 138                 close(fdout[1]);
 139         else if (cmd->out)
 140                 close(cmd->out);
 141
 142         if (need_err)
 143                 close(fderr[1]);
 144
 145         return 0;
 146 }
 147
 148 static int wait_or_whine(pid_t pid)
 149 {
 150         for (;;) {
 151                 int status, code;
 152                 pid_t waiting = waitpid(pid, &status, 0);
 153
 154                 if (waiting < 0) {
 155                         if (errno == EINTR)
 156                                 continue;
 157                         error("waitpid failed (%s)", strerror(errno));
 158                         return -ERR_RUN_COMMAND_WAITPID;
 159                 }
 160                 if (waiting != pid)
 161                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 162                 if (WIFSIGNALED(status))
 163                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 164
 165                 if (!WIFEXITED(status))
 166                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 167                 code = WEXITSTATUS(status);
 168                 if (code)
 169                         return -code;
 170                 return 0;
 171         }
 172 }
 173
 174 int finish_command(struct child_process *cmd)
 175 {
 176         return wait_or_whine(cmd->pid);
 177 }
 178
 179 int run_command(struct child_process *cmd)
 180 {
 181         int code = start_command(cmd);
 182         if (code)
 183                 return code;
 184         return finish_command(cmd);
 185 }
 186
 187 static void prepare_run_command_v_opt(struct child_process *cmd,
 188                                       const char **argv,
 189                                       int opt)
 190 {
 191         memset(cmd, 0, sizeof(*cmd));
 192         cmd->argv = argv;
 193         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 194         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 195         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 196 }
 197
 198 int run_command_v_opt(const char **argv, int opt)
 199 {
 200         struct child_process cmd;
 201         prepare_run_command_v_opt(&cmd, argv, opt);
 202         return run_command(&cmd);
 203 }
 204
 205 int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
 206 {
 207         struct child_process cmd;
 208         prepare_run_command_v_opt(&cmd, argv, opt);
 209         cmd.dir = dir;
 210         return run_command(&cmd);
 211 }
 212
 213 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 214 {
 215         struct child_process cmd;
 216         prepare_run_command_v_opt(&cmd, argv, opt);
 217         cmd.dir = dir;
 218         cmd.env = env;
 219         return run_command(&cmd);
 220 }
 221
 222 int start_async(struct async *async)
 223 {
 224         int pipe_out[2];
 225
 226         if (pipe(pipe_out) < 0)
 227                 return error("cannot create pipe: %s", strerror(errno));
 228
 229         async->pid = fork();
 230         if (async->pid < 0) {
 231                 error("fork (async) failed: %s", strerror(errno));
 232                 close_pair(pipe_out);
 233                 return -1;
 234         }
 235         if (!async->pid) {
 236                 close(pipe_out[0]);
 237                 exit(!!async->proc(pipe_out[1], async->data));
 238         }
 239         async->out = pipe_out[0];
 240         close(pipe_out[1]);
 241         return 0;
 242 }
 243
 244 int finish_async(struct async *async)
 245 {
 246         int ret = 0;
 247
 248         if (wait_or_whine(async->pid))
 249                 ret = error("waitpid (async) failed");
 250         return ret;
 251 }