Andrew's git / gitweb.git / run-command.c
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run-command.con commit sane_execvp(): ignore non-directory on $PATH (a785508)
   1#include "cache.h"
   2#include "run-command.h"
   3#include "exec_cmd.h"
   4#include "argv-array.h"
   5
   6static inline void close_pair(int fd[2])
   7{
   8        close(fd[0]);
   9        close(fd[1]);
  10}
  11
  12#ifndef WIN32
  13static inline void dup_devnull(int to)
  14{
  15        int fd = open("/dev/null", O_RDWR);
  16        dup2(fd, to);
  17        close(fd);
  18}
  19#endif
  20
  21static char *locate_in_PATH(const char *file)
  22{
  23        const char *p = getenv("PATH");
  24        struct strbuf buf = STRBUF_INIT;
  25
  26        if (!p || !*p)
  27                return NULL;
  28
  29        while (1) {
  30                const char *end = strchrnul(p, ':');
  31
  32                strbuf_reset(&buf);
  33
  34                /* POSIX specifies an empty entry as the current directory. */
  35                if (end != p) {
  36                        strbuf_add(&buf, p, end - p);
  37                        strbuf_addch(&buf, '/');
  38                }
  39                strbuf_addstr(&buf, file);
  40
  41                if (!access(buf.buf, F_OK))
  42                        return strbuf_detach(&buf, NULL);
  43
  44                if (!*end)
  45                        break;
  46                p = end + 1;
  47        }
  48
  49        strbuf_release(&buf);
  50        return NULL;
  51}
  52
  53static int exists_in_PATH(const char *file)
  54{
  55        char *r = locate_in_PATH(file);
  56        free(r);
  57        return r != NULL;
  58}
  59
  60int sane_execvp(const char *file, char * const argv[])
  61{
  62        if (!execvp(file, argv))
  63                return 0; /* cannot happen ;-) */
  64
  65        /*
  66         * When a command can't be found because one of the directories
  67         * listed in $PATH is unsearchable, execvp reports EACCES, but
  68         * careful usability testing (read: analysis of occasional bug
  69         * reports) reveals that "No such file or directory" is more
  70         * intuitive.
  71         *
  72         * We avoid commands with "/", because execvp will not do $PATH
  73         * lookups in that case.
  74         *
  75         * The reassignment of EACCES to errno looks like a no-op below,
  76         * but we need to protect against exists_in_PATH overwriting errno.
  77         */
  78        if (errno == EACCES && !strchr(file, '/'))
  79                errno = exists_in_PATH(file) ? EACCES : ENOENT;
  80        else if (errno == ENOTDIR && !strchr(file, '/'))
  81                errno = ENOENT;
  82        return -1;
  83}
  84
  85static const char **prepare_shell_cmd(const char **argv)
  86{
  87        int argc, nargc = 0;
  88        const char **nargv;
  89
  90        for (argc = 0; argv[argc]; argc++)
  91                ; /* just counting */
  92        /* +1 for NULL, +3 for "sh -c" plus extra $0 */
  93        nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
  94
  95        if (argc < 1)
  96                die("BUG: shell command is empty");
  97
  98        if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
  99                nargv[nargc++] = "sh";
 100                nargv[nargc++] = "-c";
 101
 102                if (argc < 2)
 103                        nargv[nargc++] = argv[0];
 104                else {
 105                        struct strbuf arg0 = STRBUF_INIT;
 106                        strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 107                        nargv[nargc++] = strbuf_detach(&arg0, NULL);
 108                }
 109        }
 110
 111        for (argc = 0; argv[argc]; argc++)
 112                nargv[nargc++] = argv[argc];
 113        nargv[nargc] = NULL;
 114
 115        return nargv;
 116}
 117
 118#ifndef WIN32
 119static int execv_shell_cmd(const char **argv)
 120{
 121        const char **nargv = prepare_shell_cmd(argv);
 122        trace_argv_printf(nargv, "trace: exec:");
 123        sane_execvp(nargv[0], (char **)nargv);
 124        free(nargv);
 125        return -1;
 126}
 127#endif
 128
 129#ifndef WIN32
 130static int child_err = 2;
 131static int child_notifier = -1;
 132
 133static void notify_parent(void)
 134{
 135        /*
 136         * execvp failed.  If possible, we'd like to let start_command
 137         * know, so failures like ENOENT can be handled right away; but
 138         * otherwise, finish_command will still report the error.
 139         */
 140        xwrite(child_notifier, "", 1);
 141}
 142
 143static NORETURN void die_child(const char *err, va_list params)
 144{
 145        vwritef(child_err, "fatal: ", err, params);
 146        exit(128);
 147}
 148
 149static void error_child(const char *err, va_list params)
 150{
 151        vwritef(child_err, "error: ", err, params);
 152}
 153#endif
 154
 155static inline void set_cloexec(int fd)
 156{
 157        int flags = fcntl(fd, F_GETFD);
 158        if (flags >= 0)
 159                fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 160}
 161
 162static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 163{
 164        int status, code = -1;
 165        pid_t waiting;
 166        int failed_errno = 0;
 167
 168        while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 169                ;       /* nothing */
 170
 171        if (waiting < 0) {
 172                failed_errno = errno;
 173                error("waitpid for %s failed: %s", argv0, strerror(errno));
 174        } else if (waiting != pid) {
 175                error("waitpid is confused (%s)", argv0);
 176        } else if (WIFSIGNALED(status)) {
 177                code = WTERMSIG(status);
 178                error("%s died of signal %d", argv0, code);
 179                /*
 180                 * This return value is chosen so that code & 0xff
 181                 * mimics the exit code that a POSIX shell would report for
 182                 * a program that died from this signal.
 183                 */
 184                code -= 128;
 185        } else if (WIFEXITED(status)) {
 186                code = WEXITSTATUS(status);
 187                /*
 188                 * Convert special exit code when execvp failed.
 189                 */
 190                if (code == 127) {
 191                        code = -1;
 192                        failed_errno = ENOENT;
 193                }
 194        } else {
 195                error("waitpid is confused (%s)", argv0);
 196        }
 197        errno = failed_errno;
 198        return code;
 199}
 200
 201int start_command(struct child_process *cmd)
 202{
 203        int need_in, need_out, need_err;
 204        int fdin[2], fdout[2], fderr[2];
 205        int failed_errno = failed_errno;
 206
 207        /*
 208         * In case of errors we must keep the promise to close FDs
 209         * that have been passed in via ->in and ->out.
 210         */
 211
 212        need_in = !cmd->no_stdin && cmd->in < 0;
 213        if (need_in) {
 214                if (pipe(fdin) < 0) {
 215                        failed_errno = errno;
 216                        if (cmd->out > 0)
 217                                close(cmd->out);
 218                        goto fail_pipe;
 219                }
 220                cmd->in = fdin[1];
 221        }
 222
 223        need_out = !cmd->no_stdout
 224                && !cmd->stdout_to_stderr
 225                && cmd->out < 0;
 226        if (need_out) {
 227                if (pipe(fdout) < 0) {
 228                        failed_errno = errno;
 229                        if (need_in)
 230                                close_pair(fdin);
 231                        else if (cmd->in)
 232                                close(cmd->in);
 233                        goto fail_pipe;
 234                }
 235                cmd->out = fdout[0];
 236        }
 237
 238        need_err = !cmd->no_stderr && cmd->err < 0;
 239        if (need_err) {
 240                if (pipe(fderr) < 0) {
 241                        failed_errno = errno;
 242                        if (need_in)
 243                                close_pair(fdin);
 244                        else if (cmd->in)
 245                                close(cmd->in);
 246                        if (need_out)
 247                                close_pair(fdout);
 248                        else if (cmd->out)
 249                                close(cmd->out);
 250fail_pipe:
 251                        error("cannot create pipe for %s: %s",
 252                                cmd->argv[0], strerror(failed_errno));
 253                        errno = failed_errno;
 254                        return -1;
 255                }
 256                cmd->err = fderr[0];
 257        }
 258
 259        trace_argv_printf(cmd->argv, "trace: run_command:");
 260        fflush(NULL);
 261
 262#ifndef WIN32
 263{
 264        int notify_pipe[2];
 265        if (pipe(notify_pipe))
 266                notify_pipe[0] = notify_pipe[1] = -1;
 267
 268        cmd->pid = fork();
 269        if (!cmd->pid) {
 270                /*
 271                 * Redirect the channel to write syscall error messages to
 272                 * before redirecting the process's stderr so that all die()
 273                 * in subsequent call paths use the parent's stderr.
 274                 */
 275                if (cmd->no_stderr || need_err) {
 276                        child_err = dup(2);
 277                        set_cloexec(child_err);
 278                }
 279                set_die_routine(die_child);
 280                set_error_routine(error_child);
 281
 282                close(notify_pipe[0]);
 283                set_cloexec(notify_pipe[1]);
 284                child_notifier = notify_pipe[1];
 285                atexit(notify_parent);
 286
 287                if (cmd->no_stdin)
 288                        dup_devnull(0);
 289                else if (need_in) {
 290                        dup2(fdin[0], 0);
 291                        close_pair(fdin);
 292                } else if (cmd->in) {
 293                        dup2(cmd->in, 0);
 294                        close(cmd->in);
 295                }
 296
 297                if (cmd->no_stderr)
 298                        dup_devnull(2);
 299                else if (need_err) {
 300                        dup2(fderr[1], 2);
 301                        close_pair(fderr);
 302                } else if (cmd->err > 1) {
 303                        dup2(cmd->err, 2);
 304                        close(cmd->err);
 305                }
 306
 307                if (cmd->no_stdout)
 308                        dup_devnull(1);
 309                else if (cmd->stdout_to_stderr)
 310                        dup2(2, 1);
 311                else if (need_out) {
 312                        dup2(fdout[1], 1);
 313                        close_pair(fdout);
 314                } else if (cmd->out > 1) {
 315                        dup2(cmd->out, 1);
 316                        close(cmd->out);
 317                }
 318
 319                if (cmd->dir && chdir(cmd->dir))
 320                        die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 321                            cmd->dir);
 322                if (cmd->env) {
 323                        for (; *cmd->env; cmd->env++) {
 324                                if (strchr(*cmd->env, '='))
 325                                        putenv((char *)*cmd->env);
 326                                else
 327                                        unsetenv(*cmd->env);
 328                        }
 329                }
 330                if (cmd->preexec_cb) {
 331                        /*
 332                         * We cannot predict what the pre-exec callback does.
 333                         * Forgo parent notification.
 334                         */
 335                        close(child_notifier);
 336                        child_notifier = -1;
 337
 338                        cmd->preexec_cb();
 339                }
 340                if (cmd->git_cmd) {
 341                        execv_git_cmd(cmd->argv);
 342                } else if (cmd->use_shell) {
 343                        execv_shell_cmd(cmd->argv);
 344                } else {
 345                        sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 346                }
 347                if (errno == ENOENT) {
 348                        if (!cmd->silent_exec_failure)
 349                                error("cannot run %s: %s", cmd->argv[0],
 350                                        strerror(ENOENT));
 351                        exit(127);
 352                } else {
 353                        die_errno("cannot exec '%s'", cmd->argv[0]);
 354                }
 355        }
 356        if (cmd->pid < 0)
 357                error("cannot fork() for %s: %s", cmd->argv[0],
 358                        strerror(failed_errno = errno));
 359
 360        /*
 361         * Wait for child's execvp. If the execvp succeeds (or if fork()
 362         * failed), EOF is seen immediately by the parent. Otherwise, the
 363         * child process sends a single byte.
 364         * Note that use of this infrastructure is completely advisory,
 365         * therefore, we keep error checks minimal.
 366         */
 367        close(notify_pipe[1]);
 368        if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 369                /*
 370                 * At this point we know that fork() succeeded, but execvp()
 371                 * failed. Errors have been reported to our stderr.
 372                 */
 373                wait_or_whine(cmd->pid, cmd->argv[0],
 374                              cmd->silent_exec_failure);
 375                failed_errno = errno;
 376                cmd->pid = -1;
 377        }
 378        close(notify_pipe[0]);
 379}
 380#else
 381{
 382        int fhin = 0, fhout = 1, fherr = 2;
 383        const char **sargv = cmd->argv;
 384        char **env = environ;
 385
 386        if (cmd->no_stdin)
 387                fhin = open("/dev/null", O_RDWR);
 388        else if (need_in)
 389                fhin = dup(fdin[0]);
 390        else if (cmd->in)
 391                fhin = dup(cmd->in);
 392
 393        if (cmd->no_stderr)
 394                fherr = open("/dev/null", O_RDWR);
 395        else if (need_err)
 396                fherr = dup(fderr[1]);
 397        else if (cmd->err > 2)
 398                fherr = dup(cmd->err);
 399
 400        if (cmd->no_stdout)
 401                fhout = open("/dev/null", O_RDWR);
 402        else if (cmd->stdout_to_stderr)
 403                fhout = dup(fherr);
 404        else if (need_out)
 405                fhout = dup(fdout[1]);
 406        else if (cmd->out > 1)
 407                fhout = dup(cmd->out);
 408
 409        if (cmd->env)
 410                env = make_augmented_environ(cmd->env);
 411
 412        if (cmd->git_cmd) {
 413                cmd->argv = prepare_git_cmd(cmd->argv);
 414        } else if (cmd->use_shell) {
 415                cmd->argv = prepare_shell_cmd(cmd->argv);
 416        }
 417
 418        cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 419                                  fhin, fhout, fherr);
 420        failed_errno = errno;
 421        if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 422                error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 423
 424        if (cmd->env)
 425                free_environ(env);
 426        if (cmd->git_cmd)
 427                free(cmd->argv);
 428
 429        cmd->argv = sargv;
 430        if (fhin != 0)
 431                close(fhin);
 432        if (fhout != 1)
 433                close(fhout);
 434        if (fherr != 2)
 435                close(fherr);
 436}
 437#endif
 438
 439        if (cmd->pid < 0) {
 440                if (need_in)
 441                        close_pair(fdin);
 442                else if (cmd->in)
 443                        close(cmd->in);
 444                if (need_out)
 445                        close_pair(fdout);
 446                else if (cmd->out)
 447                        close(cmd->out);
 448                if (need_err)
 449                        close_pair(fderr);
 450                else if (cmd->err)
 451                        close(cmd->err);
 452                errno = failed_errno;
 453                return -1;
 454        }
 455
 456        if (need_in)
 457                close(fdin[0]);
 458        else if (cmd->in)
 459                close(cmd->in);
 460
 461        if (need_out)
 462                close(fdout[1]);
 463        else if (cmd->out)
 464                close(cmd->out);
 465
 466        if (need_err)
 467                close(fderr[1]);
 468        else if (cmd->err)
 469                close(cmd->err);
 470
 471        return 0;
 472}
 473
 474int finish_command(struct child_process *cmd)
 475{
 476        return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 477}
 478
 479int run_command(struct child_process *cmd)
 480{
 481        int code = start_command(cmd);
 482        if (code)
 483                return code;
 484        return finish_command(cmd);
 485}
 486
 487static void prepare_run_command_v_opt(struct child_process *cmd,
 488                                      const char **argv,
 489                                      int opt)
 490{
 491        memset(cmd, 0, sizeof(*cmd));
 492        cmd->argv = argv;
 493        cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 494        cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 495        cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 496        cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 497        cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 498}
 499
 500int run_command_v_opt(const char **argv, int opt)
 501{
 502        struct child_process cmd;
 503        prepare_run_command_v_opt(&cmd, argv, opt);
 504        return run_command(&cmd);
 505}
 506
 507int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 508{
 509        struct child_process cmd;
 510        prepare_run_command_v_opt(&cmd, argv, opt);
 511        cmd.dir = dir;
 512        cmd.env = env;
 513        return run_command(&cmd);
 514}
 515
 516#ifndef NO_PTHREADS
 517static pthread_t main_thread;
 518static int main_thread_set;
 519static pthread_key_t async_key;
 520
 521static void *run_thread(void *data)
 522{
 523        struct async *async = data;
 524        intptr_t ret;
 525
 526        pthread_setspecific(async_key, async);
 527        ret = async->proc(async->proc_in, async->proc_out, async->data);
 528        return (void *)ret;
 529}
 530
 531static NORETURN void die_async(const char *err, va_list params)
 532{
 533        vreportf("fatal: ", err, params);
 534
 535        if (!pthread_equal(main_thread, pthread_self())) {
 536                struct async *async = pthread_getspecific(async_key);
 537                if (async->proc_in >= 0)
 538                        close(async->proc_in);
 539                if (async->proc_out >= 0)
 540                        close(async->proc_out);
 541                pthread_exit((void *)128);
 542        }
 543
 544        exit(128);
 545}
 546#endif
 547
 548int start_async(struct async *async)
 549{
 550        int need_in, need_out;
 551        int fdin[2], fdout[2];
 552        int proc_in, proc_out;
 553
 554        need_in = async->in < 0;
 555        if (need_in) {
 556                if (pipe(fdin) < 0) {
 557                        if (async->out > 0)
 558                                close(async->out);
 559                        return error("cannot create pipe: %s", strerror(errno));
 560                }
 561                async->in = fdin[1];
 562        }
 563
 564        need_out = async->out < 0;
 565        if (need_out) {
 566                if (pipe(fdout) < 0) {
 567                        if (need_in)
 568                                close_pair(fdin);
 569                        else if (async->in)
 570                                close(async->in);
 571                        return error("cannot create pipe: %s", strerror(errno));
 572                }
 573                async->out = fdout[0];
 574        }
 575
 576        if (need_in)
 577                proc_in = fdin[0];
 578        else if (async->in)
 579                proc_in = async->in;
 580        else
 581                proc_in = -1;
 582
 583        if (need_out)
 584                proc_out = fdout[1];
 585        else if (async->out)
 586                proc_out = async->out;
 587        else
 588                proc_out = -1;
 589
 590#ifdef NO_PTHREADS
 591        /* Flush stdio before fork() to avoid cloning buffers */
 592        fflush(NULL);
 593
 594        async->pid = fork();
 595        if (async->pid < 0) {
 596                error("fork (async) failed: %s", strerror(errno));
 597                goto error;
 598        }
 599        if (!async->pid) {
 600                if (need_in)
 601                        close(fdin[1]);
 602                if (need_out)
 603                        close(fdout[0]);
 604                exit(!!async->proc(proc_in, proc_out, async->data));
 605        }
 606
 607        if (need_in)
 608                close(fdin[0]);
 609        else if (async->in)
 610                close(async->in);
 611
 612        if (need_out)
 613                close(fdout[1]);
 614        else if (async->out)
 615                close(async->out);
 616#else
 617        if (!main_thread_set) {
 618                /*
 619                 * We assume that the first time that start_async is called
 620                 * it is from the main thread.
 621                 */
 622                main_thread_set = 1;
 623                main_thread = pthread_self();
 624                pthread_key_create(&async_key, NULL);
 625                set_die_routine(die_async);
 626        }
 627
 628        if (proc_in >= 0)
 629                set_cloexec(proc_in);
 630        if (proc_out >= 0)
 631                set_cloexec(proc_out);
 632        async->proc_in = proc_in;
 633        async->proc_out = proc_out;
 634        {
 635                int err = pthread_create(&async->tid, NULL, run_thread, async);
 636                if (err) {
 637                        error("cannot create thread: %s", strerror(err));
 638                        goto error;
 639                }
 640        }
 641#endif
 642        return 0;
 643
 644error:
 645        if (need_in)
 646                close_pair(fdin);
 647        else if (async->in)
 648                close(async->in);
 649
 650        if (need_out)
 651                close_pair(fdout);
 652        else if (async->out)
 653                close(async->out);
 654        return -1;
 655}
 656
 657int finish_async(struct async *async)
 658{
 659#ifdef NO_PTHREADS
 660        return wait_or_whine(async->pid, "child process", 0);
 661#else
 662        void *ret = (void *)(intptr_t)(-1);
 663
 664        if (pthread_join(async->tid, &ret))
 665                error("pthread_join failed");
 666        return (int)(intptr_t)ret;
 667#endif
 668}
 669
 670int run_hook(const char *index_file, const char *name, ...)
 671{
 672        struct child_process hook;
 673        struct argv_array argv = ARGV_ARRAY_INIT;
 674        const char *p, *env[2];
 675        char index[PATH_MAX];
 676        va_list args;
 677        int ret;
 678
 679        if (access(git_path("hooks/%s", name), X_OK) < 0)
 680                return 0;
 681
 682        va_start(args, name);
 683        argv_array_push(&argv, git_path("hooks/%s", name));
 684        while ((p = va_arg(args, const char *)))
 685                argv_array_push(&argv, p);
 686        va_end(args);
 687
 688        memset(&hook, 0, sizeof(hook));
 689        hook.argv = argv.argv;
 690        hook.no_stdin = 1;
 691        hook.stdout_to_stderr = 1;
 692        if (index_file) {
 693                snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 694                env[0] = index;
 695                env[1] = NULL;
 696                hook.env = env;
 697        }
 698
 699        ret = run_command(&hook);
 700        argv_array_clear(&argv);
 701        return ret;
 702}