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;
  21         int fdin[2], fdout[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         cmd->pid = fork();
  45         if (cmd->pid < 0) {
  46                 if (need_in)
  47                         close_pair(fdin);
  48                 if (need_out)
  49                         close_pair(fdout);
  50                 return -ERR_RUN_COMMAND_FORK;
  51         }
  52
  53         if (!cmd->pid) {
  54                 if (cmd->no_stdin)
  55                         dup_devnull(0);
  56                 else if (need_in) {
  57                         dup2(fdin[0], 0);
  58                         close_pair(fdin);
  59                 } else if (cmd->in) {
  60                         dup2(cmd->in, 0);
  61                         close(cmd->in);
  62                 }
  63
  64                 if (cmd->no_stdout)
  65                         dup_devnull(1);
  66                 else if (cmd->stdout_to_stderr)
  67                         dup2(2, 1);
  68                 else if (need_out) {
  69                         dup2(fdout[1], 1);
  70                         close_pair(fdout);
  71                 } else if (cmd->out > 1) {
  72                         dup2(cmd->out, 1);
  73                         close(cmd->out);
  74                 }
  75
  76                 if (cmd->dir && chdir(cmd->dir))
  77                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
  78                             cmd->dir, strerror(errno));
  79                 if (cmd->git_cmd) {
  80                         execv_git_cmd(cmd->argv);
  81                 } else {
  82                         execvp(cmd->argv[0], (char *const*) cmd->argv);
  83                 }
  84                 die("exec %s failed.", cmd->argv[0]);
  85         }
  86
  87         if (need_in)
  88                 close(fdin[0]);
  89         else if (cmd->in)
  90                 close(cmd->in);
  91
  92         if (need_out)
  93                 close(fdout[1]);
  94         else if (cmd->out > 1)
  95                 close(cmd->out);
  96
  97         return 0;
  98 }
  99
 100 int finish_command(struct child_process *cmd)
 101 {
 102         if (cmd->close_in)
 103                 close(cmd->in);
 104         if (cmd->close_out)
 105                 close(cmd->out);
 106
 107         for (;;) {
 108                 int status, code;
 109                 pid_t waiting = waitpid(cmd->pid, &status, 0);
 110
 111                 if (waiting < 0) {
 112                         if (errno == EINTR)
 113                                 continue;
 114                         error("waitpid failed (%s)", strerror(errno));
 115                         return -ERR_RUN_COMMAND_WAITPID;
 116                 }
 117                 if (waiting != cmd->pid)
 118                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 119                 if (WIFSIGNALED(status))
 120                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 121
 122                 if (!WIFEXITED(status))
 123                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 124                 code = WEXITSTATUS(status);
 125                 if (code)
 126                         return -code;
 127                 return 0;
 128         }
 129 }
 130
 131 int run_command(struct child_process *cmd)
 132 {
 133         int code = start_command(cmd);
 134         if (code)
 135                 return code;
 136         return finish_command(cmd);
 137 }
 138
 139 static void prepare_run_command_v_opt(struct child_process *cmd,
 140                                       const char **argv, int opt)
 141 {
 142         memset(cmd, 0, sizeof(*cmd));
 143         cmd->argv = argv;
 144         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 145         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 146         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 147 }
 148
 149 int run_command_v_opt(const char **argv, int opt)
 150 {
 151         struct child_process cmd;
 152         prepare_run_command_v_opt(&cmd, argv, opt);
 153         return run_command(&cmd);
 154 }
 155
 156 int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
 157 {
 158         struct child_process cmd;
 159         prepare_run_command_v_opt(&cmd, argv, opt);
 160         cmd.dir = dir;
 161         return run_command(&cmd);
 162 }