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