tools/perf/util/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         /*
  24          * In case of errors we must keep the promise to close FDs
  25          * that have been passed in via ->in and ->out.
  26          */
  27
  28         need_in = !cmd->no_stdin && cmd->in < 0;
  29         if (need_in) {
  30                 if (pipe(fdin) < 0) {
  31                         if (cmd->out > 0)
  32                                 close(cmd->out);
  33                         return -ERR_RUN_COMMAND_PIPE;
  34                 }
  35                 cmd->in = fdin[1];
  36         }
  37
  38         need_out = !cmd->no_stdout
  39                 && !cmd->stdout_to_stderr
  40                 && cmd->out < 0;
  41         if (need_out) {
  42                 if (pipe(fdout) < 0) {
  43                         if (need_in)
  44                                 close_pair(fdin);
  45                         else if (cmd->in)
  46                                 close(cmd->in);
  47                         return -ERR_RUN_COMMAND_PIPE;
  48                 }
  49                 cmd->out = fdout[0];
  50         }
  51
  52         need_err = !cmd->no_stderr && cmd->err < 0;
  53         if (need_err) {
  54                 if (pipe(fderr) < 0) {
  55                         if (need_in)
  56                                 close_pair(fdin);
  57                         else if (cmd->in)
  58                                 close(cmd->in);
  59                         if (need_out)
  60                                 close_pair(fdout);
  61                         else if (cmd->out)
  62                                 close(cmd->out);
  63                         return -ERR_RUN_COMMAND_PIPE;
  64                 }
  65                 cmd->err = fderr[0];
  66         }
  67
  68         fflush(NULL);
  69         cmd->pid = fork();
  70         if (!cmd->pid) {
  71                 if (cmd->no_stdin)
  72                         dup_devnull(0);
  73                 else if (need_in) {
  74                         dup2(fdin[0], 0);
  75                         close_pair(fdin);
  76                 } else if (cmd->in) {
  77                         dup2(cmd->in, 0);
  78                         close(cmd->in);
  79                 }
  80
  81                 if (cmd->no_stderr)
  82                         dup_devnull(2);
  83                 else if (need_err) {
  84                         dup2(fderr[1], 2);
  85                         close_pair(fderr);
  86                 }
  87
  88                 if (cmd->no_stdout)
  89                         dup_devnull(1);
  90                 else if (cmd->stdout_to_stderr)
  91                         dup2(2, 1);
  92                 else if (need_out) {
  93                         dup2(fdout[1], 1);
  94                         close_pair(fdout);
  95                 } else if (cmd->out > 1) {
  96                         dup2(cmd->out, 1);
  97                         close(cmd->out);
  98                 }
  99
 100                 if (cmd->dir && chdir(cmd->dir))
 101                         die("exec %s: cd to %s failed (%s)", cmd->argv[0],
 102                             cmd->dir, strerror(errno));
 103                 if (cmd->env) {
 104                         for (; *cmd->env; cmd->env++) {
 105                                 if (strchr(*cmd->env, '='))
 106                                         putenv((char*)*cmd->env);
 107                                 else
 108                                         unsetenv(*cmd->env);
 109                         }
 110                 }
 111                 if (cmd->preexec_cb)
 112                         cmd->preexec_cb();
 113                 if (cmd->perf_cmd) {
 114                         execv_perf_cmd(cmd->argv);
 115                 } else {
 116                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 117                 }
 118                 exit(127);
 119         }
 120
 121         if (cmd->pid < 0) {
 122                 int err = errno;
 123                 if (need_in)
 124                         close_pair(fdin);
 125                 else if (cmd->in)
 126                         close(cmd->in);
 127                 if (need_out)
 128                         close_pair(fdout);
 129                 else if (cmd->out)
 130                         close(cmd->out);
 131                 if (need_err)
 132                         close_pair(fderr);
 133                 return err == ENOENT ?
 134                         -ERR_RUN_COMMAND_EXEC :
 135                         -ERR_RUN_COMMAND_FORK;
 136         }
 137
 138         if (need_in)
 139                 close(fdin[0]);
 140         else if (cmd->in)
 141                 close(cmd->in);
 142
 143         if (need_out)
 144                 close(fdout[1]);
 145         else if (cmd->out)
 146                 close(cmd->out);
 147
 148         if (need_err)
 149                 close(fderr[1]);
 150
 151         return 0;
 152 }
 153
 154 static int wait_or_whine(pid_t pid)
 155 {
 156         for (;;) {
 157                 int status, code;
 158                 pid_t waiting = waitpid(pid, &status, 0);
 159
 160                 if (waiting < 0) {
 161                         if (errno == EINTR)
 162                                 continue;
 163                         error("waitpid failed (%s)", strerror(errno));
 164                         return -ERR_RUN_COMMAND_WAITPID;
 165                 }
 166                 if (waiting != pid)
 167                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 168                 if (WIFSIGNALED(status))
 169                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 170
 171                 if (!WIFEXITED(status))
 172                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 173                 code = WEXITSTATUS(status);
 174                 switch (code) {
 175                 case 127:
 176                         return -ERR_RUN_COMMAND_EXEC;
 177                 case 0:
 178                         return 0;
 179                 default:
 180                         return -code;
 181                 }
 182         }
 183 }
 184
 185 int finish_command(struct child_process *cmd)
 186 {
 187         return wait_or_whine(cmd->pid);
 188 }
 189
 190 int run_command(struct child_process *cmd)
 191 {
 192         int code = start_command(cmd);
 193         if (code)
 194                 return code;
 195         return finish_command(cmd);
 196 }
 197
 198 static void prepare_run_command_v_opt(struct child_process *cmd,
 199                                       const char **argv,
 200                                       int opt)
 201 {
 202         memset(cmd, 0, sizeof(*cmd));
 203         cmd->argv = argv;
 204         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 205         cmd->perf_cmd = opt & RUN_PERF_CMD ? 1 : 0;
 206         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 207 }
 208
 209 int run_command_v_opt(const char **argv, int opt)
 210 {
 211         struct child_process cmd;
 212         prepare_run_command_v_opt(&cmd, argv, opt);
 213         return run_command(&cmd);
 214 }
 215
 216 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 217 {
 218         struct child_process cmd;
 219         prepare_run_command_v_opt(&cmd, argv, opt);
 220         cmd.dir = dir;
 221         cmd.env = env;
 222         return run_command(&cmd);
 223 }
 224
 225 int start_async(struct async *async)
 226 {
 227         int pipe_out[2];
 228
 229         if (pipe(pipe_out) < 0)
 230                 return error("cannot create pipe: %s", strerror(errno));
 231         async->out = pipe_out[0];
 232
 233         /* Flush stdio before fork() to avoid cloning buffers */
 234         fflush(NULL);
 235
 236         async->pid = fork();
 237         if (async->pid < 0) {
 238                 error("fork (async) failed: %s", strerror(errno));
 239                 close_pair(pipe_out);
 240                 return -1;
 241         }
 242         if (!async->pid) {
 243                 close(pipe_out[0]);
 244                 exit(!!async->proc(pipe_out[1], async->data));
 245         }
 246         close(pipe_out[1]);
 247
 248         return 0;
 249 }
 250
 251 int finish_async(struct async *async)
 252 {
 253         int ret = 0;
 254
 255         if (wait_or_whine(async->pid))
 256                 ret = error("waitpid (async) failed");
 257
 258         return ret;
 259 }
 260
 261 int run_hook(const char *index_file, const char *name, ...)
 262 {
 263         struct child_process hook;
 264         const char **argv = NULL, *env[2];
 265         char idx[PATH_MAX];
 266         va_list args;
 267         int ret;
 268         size_t i = 0, alloc = 0;
 269
 270         if (access(perf_path("hooks/%s", name), X_OK) < 0)
 271                 return 0;
 272
 273         va_start(args, name);
 274         ALLOC_GROW(argv, i + 1, alloc);
 275         argv[i++] = perf_path("hooks/%s", name);
 276         while (argv[i-1]) {
 277                 ALLOC_GROW(argv, i + 1, alloc);
 278                 argv[i++] = va_arg(args, const char *);
 279         }
 280         va_end(args);
 281
 282         memset(&hook, 0, sizeof(hook));
 283         hook.argv = argv;
 284         hook.no_stdin = 1;
 285         hook.stdout_to_stderr = 1;
 286         if (index_file) {
 287                 snprintf(idx, sizeof(idx), "PERF_INDEX_FILE=%s", index_file);
 288                 env[0] = idx;
 289                 env[1] = NULL;
 290                 hook.env = env;
 291         }
 292
 293         ret = start_command(&hook);
 294         free(argv);
 295         if (ret) {
 296                 warning("Could not spawn %s", argv[0]);
 297                 return ret;
 298         }
 299         ret = finish_command(&hook);
 300         if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
 301                 warning("%s exited due to uncaught signal", argv[0]);
 302
 303         return ret;
 304 }