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->env) {
  80                         for (; *cmd->env; cmd->env++) {
  81                                 if (strchr(*cmd->env, '='))
  82                                         putenv((char*)*cmd->env);
  83                                 else
  84                                         unsetenv(*cmd->env);
  85                         }
  86                 }
  87                 if (cmd->git_cmd) {
  88                         execv_git_cmd(cmd->argv);
  89                 } else {
  90                         execvp(cmd->argv[0], (char *const*) cmd->argv);
  91                 }
  92                 die("exec %s failed.", cmd->argv[0]);
  93         }
  94
  95         if (need_in)
  96                 close(fdin[0]);
  97         else if (cmd->in)
  98                 close(cmd->in);
  99
 100         if (need_out)
 101                 close(fdout[1]);
 102         else if (cmd->out > 1)
 103                 close(cmd->out);
 104
 105         return 0;
 106 }
 107
 108 int finish_command(struct child_process *cmd)
 109 {
 110         if (cmd->close_in)
 111                 close(cmd->in);
 112         if (cmd->close_out)
 113                 close(cmd->out);
 114
 115         for (;;) {
 116                 int status, code;
 117                 pid_t waiting = waitpid(cmd->pid, &status, 0);
 118
 119                 if (waiting < 0) {
 120                         if (errno == EINTR)
 121                                 continue;
 122                         error("waitpid failed (%s)", strerror(errno));
 123                         return -ERR_RUN_COMMAND_WAITPID;
 124                 }
 125                 if (waiting != cmd->pid)
 126                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 127                 if (WIFSIGNALED(status))
 128                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 129
 130                 if (!WIFEXITED(status))
 131                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 132                 code = WEXITSTATUS(status);
 133                 if (code)
 134                         return -code;
 135                 return 0;
 136         }
 137 }
 138
 139 int run_command(struct child_process *cmd)
 140 {
 141         int code = start_command(cmd);
 142         if (code)
 143                 return code;
 144         return finish_command(cmd);
 145 }
 146
 147 static void prepare_run_command_v_opt(struct child_process *cmd,
 148                                       const char **argv,
 149                                       int opt)
 150 {
 151         memset(cmd, 0, sizeof(*cmd));
 152         cmd->argv = argv;
 153         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 154         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 155         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 156 }
 157
 158 int run_command_v_opt(const char **argv, int opt)
 159 {
 160         struct child_process cmd;
 161         prepare_run_command_v_opt(&cmd, argv, opt);
 162         return run_command(&cmd);
 163 }
 164
 165 int run_command_v_opt_cd(const char **argv, int opt, const char *dir)
 166 {
 167         struct child_process cmd;
 168         prepare_run_command_v_opt(&cmd, argv, opt);
 169         cmd.dir = dir;
 170         return run_command(&cmd);
 171 }
 172
 173 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 174 {
 175         struct child_process cmd;
 176         prepare_run_command_v_opt(&cmd, argv, opt);
 177         cmd.dir = dir;
 178         cmd.env = env;
 179         return run_command(&cmd);
 180 }