kernel/tools/perf/util/run-command.c

   1 #include "cache.h"
   2 #include "run-command.h"
   3 #include "exec_cmd.h"
   4 #include "debug.h"
   5
   6 static inline void close_pair(int fd[2])
   7 {
   8         close(fd[0]);
   9         close(fd[1]);
  10 }
  11
  12 static inline void dup_devnull(int to)
  13 {
  14         int fd = open("/dev/null", O_RDWR);
  15         dup2(fd, to);
  16         close(fd);
  17 }
  18
  19 int start_command(struct child_process *cmd)
  20 {
  21         int need_in, need_out, need_err;
  22         int fdin[2], fdout[2], fderr[2];
  23         char sbuf[STRERR_BUFSIZE];
  24
  25         /*
  26          * In case of errors we must keep the promise to close FDs
  27          * that have been passed in via ->in and ->out.
  28          */
  29
  30         need_in = !cmd->no_stdin && cmd->in < 0;
  31         if (need_in) {
  32                 if (pipe(fdin) < 0) {
  33                         if (cmd->out > 0)
  34                                 close(cmd->out);
  35                         return -ERR_RUN_COMMAND_PIPE;
  36                 }
  37                 cmd->in = fdin[1];
  38         }
  39
  40         need_out = !cmd->no_stdout
  41                 && !cmd->stdout_to_stderr
  42                 && cmd->out < 0;
  43         if (need_out) {
  44                 if (pipe(fdout) < 0) {
  45                         if (need_in)
  46                                 close_pair(fdin);
  47                         else if (cmd->in)
  48                                 close(cmd->in);
  49                         return -ERR_RUN_COMMAND_PIPE;
  50                 }
  51                 cmd->out = fdout[0];
  52         }
  53
  54         need_err = !cmd->no_stderr && cmd->err < 0;
  55         if (need_err) {
  56                 if (pipe(fderr) < 0) {
  57                         if (need_in)
  58                                 close_pair(fdin);
  59                         else if (cmd->in)
  60                                 close(cmd->in);
  61                         if (need_out)
  62                                 close_pair(fdout);
  63                         else if (cmd->out)
  64                                 close(cmd->out);
  65                         return -ERR_RUN_COMMAND_PIPE;
  66                 }
  67                 cmd->err = fderr[0];
  68         }
  69
  70         fflush(NULL);
  71         cmd->pid = fork();
  72         if (!cmd->pid) {
  73                 if (cmd->no_stdin)
  74                         dup_devnull(0);
  75                 else if (need_in) {
  76                         dup2(fdin[0], 0);
  77                         close_pair(fdin);
  78                 } else if (cmd->in) {
  79                         dup2(cmd->in, 0);
  80                         close(cmd->in);
  81                 }
  82
  83                 if (cmd->no_stderr)
  84                         dup_devnull(2);
  85                 else if (need_err) {
  86                         dup2(fderr[1], 2);
  87                         close_pair(fderr);
  88                 }
  89
  90                 if (cmd->no_stdout)
  91                         dup_devnull(1);
  92                 else if (cmd->stdout_to_stderr)
  93                         dup2(2, 1);
  94                 else if (need_out) {
  95                         dup2(fdout[1], 1);
  96                         close_pair(fdout);
  97                 } else if (cmd->out > 1) {
  98                         dup2(cmd->out, 1);
  99                         close(cmd->out);
 100                 }
 101
 102                 if (cmd->dir && chdir(cmd->dir))
 103                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
 104                             cmd->dir, strerror_r(errno, sbuf, sizeof(sbuf)));
 105                 if (cmd->env) {
 106                         for (; *cmd->env; cmd->env++) {
 107                                 if (strchr(*cmd->env, '='))
 108                                         putenv((char*)*cmd->env);
 109                                 else
 110                                         unsetenv(*cmd->env);
 111                         }
 112                 }
 113                 if (cmd->preexec_cb)
 114                         cmd->preexec_cb();
 115                 if (cmd->perf_cmd) {
 116                         execv_perf_cmd(cmd->argv);
 117                 } else {
 118                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 119                 }
 120                 exit(127);
 121         }
 122
 123         if (cmd->pid < 0) {
 124                 int err = errno;
 125                 if (need_in)
 126                         close_pair(fdin);
 127                 else if (cmd->in)
 128                         close(cmd->in);
 129                 if (need_out)
 130                         close_pair(fdout);
 131                 else if (cmd->out)
 132                         close(cmd->out);
 133                 if (need_err)
 134                         close_pair(fderr);
 135                 return err == ENOENT ?
 136                         -ERR_RUN_COMMAND_EXEC :
 137                         -ERR_RUN_COMMAND_FORK;
 138         }
 139
 140         if (need_in)
 141                 close(fdin[0]);
 142         else if (cmd->in)
 143                 close(cmd->in);
 144
 145         if (need_out)
 146                 close(fdout[1]);
 147         else if (cmd->out)
 148                 close(cmd->out);
 149
 150         if (need_err)
 151                 close(fderr[1]);
 152
 153         return 0;
 154 }
 155
 156 static int wait_or_whine(pid_t pid)
 157 {
 158         char sbuf[STRERR_BUFSIZE];
 159
 160         for (;;) {
 161                 int status, code;
 162                 pid_t waiting = waitpid(pid, &status, 0);
 163
 164                 if (waiting < 0) {
 165                         if (errno == EINTR)
 166                                 continue;
 167                         error("waitpid failed (%s)",
 168                               strerror_r(errno, sbuf, sizeof(sbuf)));
 169                         return -ERR_RUN_COMMAND_WAITPID;
 170                 }
 171                 if (waiting != pid)
 172                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 173                 if (WIFSIGNALED(status))
 174                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 175
 176                 if (!WIFEXITED(status))
 177                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 178                 code = WEXITSTATUS(status);
 179                 switch (code) {
 180                 case 127:
 181                         return -ERR_RUN_COMMAND_EXEC;
 182                 case 0:
 183                         return 0;
 184                 default:
 185                         return -code;
 186                 }
 187         }
 188 }
 189
 190 int finish_command(struct child_process *cmd)
 191 {
 192         return wait_or_whine(cmd->pid);
 193 }
 194
 195 int run_command(struct child_process *cmd)
 196 {
 197         int code = start_command(cmd);
 198         if (code)
 199                 return code;
 200         return finish_command(cmd);
 201 }
 202
 203 static void prepare_run_command_v_opt(struct child_process *cmd,
 204                                       const char **argv,
 205                                       int opt)
 206 {
 207         memset(cmd, 0, sizeof(*cmd));
 208         cmd->argv = argv;
 209         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 210         cmd->perf_cmd = opt & RUN_PERF_CMD ? 1 : 0;
 211         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 212 }
 213
 214 int run_command_v_opt(const char **argv, int opt)
 215 {
 216         struct child_process cmd;
 217         prepare_run_command_v_opt(&cmd, argv, opt);
 218         return run_command(&cmd);
 219 }