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         need_in = !cmd->no_stdin && cmd->in < 0;
  24         if (need_in) {
  25                 if (pipe(fdin) < 0)
  26                         return -ERR_RUN_COMMAND_PIPE;
  27                 cmd->in = fdin[1];
  28                 cmd->close_in = 1;
  29         }
  30
  31         need_out = !cmd->no_stdout
  32                 && !cmd->stdout_to_stderr
  33                 && cmd->out < 0;
  34         if (need_out) {
  35                 if (pipe(fdout) < 0) {
  36                         if (need_in)
  37                                 close_pair(fdin);
  38                         return -ERR_RUN_COMMAND_PIPE;
  39                 }
  40                 cmd->out = fdout[0];
  41                 cmd->close_out = 1;
  42         }
  43
  44         need_err = !cmd->no_stderr && cmd->err < 0;
  45         if (need_err) {
  46                 if (pipe(fderr) < 0) {
  47                         if (need_in)
  48                                 close_pair(fdin);
  49                         if (need_out)
  50                                 close_pair(fdout);
  51                         return -ERR_RUN_COMMAND_PIPE;
  52                 }
  53                 cmd->err = fderr[0];
  54         }
  55
  56         cmd->pid = fork();
  57         if (cmd->pid < 0) {
  58                 if (need_in)
  59                         close_pair(fdin);
  60                 if (need_out)
  61                         close_pair(fdout);
  62                 if (need_err)
  63                         close_pair(fderr);
  64                 return -ERR_RUN_COMMAND_FORK;
  65         }
  66
  67         if (!cmd->pid) {
  68                 if (cmd->no_stdin)
  69                         dup_devnull(0);
  70                 else if (need_in) {
  71                         dup2(fdin[0], 0);
  72                         close_pair(fdin);
  73                 } else if (cmd->in) {
  74                         dup2(cmd->in, 0);
  75                         close(cmd->in);
  76                 }
  77
  78                 if (cmd->no_stdout)
  79                         dup_devnull(1);
  80                 else if (cmd->stdout_to_stderr)
  81                         dup2(2, 1);
  82                 else if (need_out) {
  83                         dup2(fdout[1], 1);
  84                         close_pair(fdout);
  85                 } else if (cmd->out > 1) {
  86                         dup2(cmd->out, 1);
  87                         close(cmd->out);
  88                 }
  89
  90                 if (cmd->no_stderr)
  91                         dup_devnull(2);
  92                 else if (need_err) {
  93                         dup2(fderr[1], 2);
  94                         close_pair(fderr);
  95                 }
  96
  97                 if (cmd->dir && chdir(cmd->dir))
  98                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
  99                             cmd->dir, strerror(errno));
 100                 if (cmd->env) {
 101                         for (; *cmd->env; cmd->env++) {
 102                                 if (strchr(*cmd->env, '='))
 103                                         putenv((char*)*cmd->env);
 104                                 else
 105                                         unsetenv(*cmd->env);
 106                         }
 107                 }
 108                 if (cmd->git_cmd) {
 109                         execv_git_cmd(cmd->argv);
 110                 } else {
 111                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 112                 }
 113                 die("exec %s failed.", cmd->argv[0]);
 114         }
 115
 116         if (need_in)
 117                 close(fdin[0]);
 118         else if (cmd->in)
 119                 close(cmd->in);
 120
 121         if (need_out)
 122                 close(fdout[1]);
 123         else if (cmd->out > 1)
 124                 close(cmd->out);
 125
 126         if (need_err)
 127                 close(fderr[1]);
 128
 129         return 0;
 130 }
 131
 132 static int wait_or_whine(pid_t pid)
 133 {
 134         for (;;) {
 135                 int status, code;
 136                 pid_t waiting = waitpid(pid, &status, 0);
 137
 138                 if (waiting < 0) {
 139                         if (errno == EINTR)
 140                                 continue;
 141                         error("waitpid failed (%s)", strerror(errno));
 142                         return -ERR_RUN_COMMAND_WAITPID;
 143                 }
 144                 if (waiting != pid)
 145                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 146                 if (WIFSIGNALED(status))
 147                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 148
 149                 if (!WIFEXITED(status))
 150                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 151                 code = WEXITSTATUS(status);
 152                 if (code)
 153                         return -code;
 154                 return 0;
 155         }
 156 }
 157
 158 int finish_command(struct child_process *cmd)
 159 {
 160         if (cmd->close_in)
 161                 close(cmd->in);
 162         if (cmd->close_out)
 163                 close(cmd->out);
 164         return wait_or_whine(cmd->pid);
 165 }
 166
 167 int run_command(struct child_process *cmd)
 168 {
 169         int code = start_command(cmd);
 170         if (code)
 171                 return code;
 172         return finish_command(cmd);
 173 }
 174
 175 static void prepare_run_command_v_opt(struct child_process *cmd,
 176                                       const char **argv,
 177                                       int opt)
 178 {
 179         memset(cmd, 0, sizeof(*cmd));
 180         cmd->argv = argv;
 181         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 182         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 183         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 184 }
 185
 186 int run_command_v_opt(const char **argv, int opt)
 187 {
 188         struct child_process cmd;
 189         prepare_run_command_v_opt(&cmd, argv, opt);
 190         return run_command(&cmd);
 191 }
 192
 193 int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
 194 {
 195         struct child_process cmd;
 196         prepare_run_command_v_opt(&cmd, argv, opt);
 197         cmd.dir = dir;
 198         return run_command(&cmd);
 199 }
 200
 201 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 202 {
 203         struct child_process cmd;
 204         prepare_run_command_v_opt(&cmd, argv, opt);
 205         cmd.dir = dir;
 206         cmd.env = env;
 207         return run_command(&cmd);
 208 }
 209
 210 int start_async(struct async *async)
 211 {
 212         int pipe_out[2];
 213
 214         if (pipe(pipe_out) < 0)
 215                 return error("cannot create pipe: %s", strerror(errno));
 216
 217         async->pid = fork();
 218         if (async->pid < 0) {
 219                 error("fork (async) failed: %s", strerror(errno));
 220                 close_pair(pipe_out);
 221                 return -1;
 222         }
 223         if (!async->pid) {
 224                 close(pipe_out[0]);
 225                 exit(!!async->proc(pipe_out[1], async->data));
 226         }
 227         async->out = pipe_out[0];
 228         close(pipe_out[1]);
 229         return 0;
 230 }
 231
 232 int finish_async(struct async *async)
 233 {
 234         int ret = 0;
 235
 236         if (wait_or_whine(async->pid))
 237                 ret = error("waitpid (async) failed");
 238         return ret;
 239 }