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         cmd->pid = fork();
  71         if (cmd->pid < 0) {
  72                 if (need_in)
  73                         close_pair(fdin);
  74                 else if (cmd->in)
  75                         close(cmd->in);
  76                 if (need_out)
  77                         close_pair(fdout);
  78                 else if (cmd->out)
  79                         close(cmd->out);
  80                 if (need_err)
  81                         close_pair(fderr);
  82                 return -ERR_RUN_COMMAND_FORK;
  83         }
  84
  85         if (!cmd->pid) {
  86                 if (cmd->no_stdin)
  87                         dup_devnull(0);
  88                 else if (need_in) {
  89                         dup2(fdin[0], 0);
  90                         close_pair(fdin);
  91                 } else if (cmd->in) {
  92                         dup2(cmd->in, 0);
  93                         close(cmd->in);
  94                 }
  95
  96                 if (cmd->no_stderr)
  97                         dup_devnull(2);
  98                 else if (need_err) {
  99                         dup2(fderr[1], 2);
 100                         close_pair(fderr);
 101                 }
 102
 103                 if (cmd->no_stdout)
 104                         dup_devnull(1);
 105                 else if (cmd->stdout_to_stderr)
 106                         dup2(2, 1);
 107                 else if (need_out) {
 108                         dup2(fdout[1], 1);
 109                         close_pair(fdout);
 110                 } else if (cmd->out > 1) {
 111                         dup2(cmd->out, 1);
 112                         close(cmd->out);
 113                 }
 114
 115                 if (cmd->dir && chdir(cmd->dir))
 116                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
 117                             cmd->dir, strerror(errno));
 118                 if (cmd->env) {
 119                         for (; *cmd->env; cmd->env++) {
 120                                 if (strchr(*cmd->env, '='))
 121                                         putenv((char*)*cmd->env);
 122                                 else
 123                                         unsetenv(*cmd->env);
 124                         }
 125                 }
 126                 if (cmd->git_cmd) {
 127                         execv_git_cmd(cmd->argv);
 128                 } else {
 129                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 130                 }
 131                 die("exec %s failed.", cmd->argv[0]);
 132         }
 133
 134         if (need_in)
 135                 close(fdin[0]);
 136         else if (cmd->in)
 137                 close(cmd->in);
 138
 139         if (need_out)
 140                 close(fdout[1]);
 141         else if (cmd->out)
 142                 close(cmd->out);
 143
 144         if (need_err)
 145                 close(fderr[1]);
 146
 147         return 0;
 148 }
 149
 150 static int wait_or_whine(pid_t pid)
 151 {
 152         for (;;) {
 153                 int status, code;
 154                 pid_t waiting = waitpid(pid, &status, 0);
 155
 156                 if (waiting < 0) {
 157                         if (errno == EINTR)
 158                                 continue;
 159                         error("waitpid failed (%s)", strerror(errno));
 160                         return -ERR_RUN_COMMAND_WAITPID;
 161                 }
 162                 if (waiting != pid)
 163                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 164                 if (WIFSIGNALED(status))
 165                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 166
 167                 if (!WIFEXITED(status))
 168                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 169                 code = WEXITSTATUS(status);
 170                 if (code)
 171                         return -code;
 172                 return 0;
 173         }
 174 }
 175
 176 int finish_command(struct child_process *cmd)
 177 {
 178         return wait_or_whine(cmd->pid);
 179 }
 180
 181 int run_command(struct child_process *cmd)
 182 {
 183         int code = start_command(cmd);
 184         if (code)
 185                 return code;
 186         return finish_command(cmd);
 187 }
 188
 189 static void prepare_run_command_v_opt(struct child_process *cmd,
 190                                       const char **argv,
 191                                       int opt)
 192 {
 193         memset(cmd, 0, sizeof(*cmd));
 194         cmd->argv = argv;
 195         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 196         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 197         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 198 }
 199
 200 int run_command_v_opt(const char **argv, int opt)
 201 {
 202         struct child_process cmd;
 203         prepare_run_command_v_opt(&cmd, argv, opt);
 204         return run_command(&cmd);
 205 }
 206
 207 int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
 208 {
 209         struct child_process cmd;
 210         prepare_run_command_v_opt(&cmd, argv, opt);
 211         cmd.dir = dir;
 212         return run_command(&cmd);
 213 }
 214
 215 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 216 {
 217         struct child_process cmd;
 218         prepare_run_command_v_opt(&cmd, argv, opt);
 219         cmd.dir = dir;
 220         cmd.env = env;
 221         return run_command(&cmd);
 222 }
 223
 224 int start_async(struct async *async)
 225 {
 226         int pipe_out[2];
 227
 228         if (pipe(pipe_out) < 0)
 229                 return error("cannot create pipe: %s", strerror(errno));
 230
 231         async->pid = fork();
 232         if (async->pid < 0) {
 233                 error("fork (async) failed: %s", strerror(errno));
 234                 close_pair(pipe_out);
 235                 return -1;
 236         }
 237         if (!async->pid) {
 238                 close(pipe_out[0]);
 239                 exit(!!async->proc(pipe_out[1], async->data));
 240         }
 241         async->out = pipe_out[0];
 242         close(pipe_out[1]);
 243         return 0;
 244 }
 245
 246 int finish_async(struct async *async)
 247 {
 248         int ret = 0;
 249
 250         if (wait_or_whine(async->pid))
 251                 ret = error("waitpid (async) failed");
 252         return ret;
 253 }