Andrew's git / gitweb.git / run-command.c
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run-command.con commit Merge branch 'ct/advise-push-default' (c5da24a)
   1#include "cache.h"
   2#include "run-command.h"
   3#include "exec_cmd.h"
   4#include "sigchain.h"
   5#include "argv-array.h"
   6
   7#ifndef SHELL_PATH
   8# define SHELL_PATH "/bin/sh"
   9#endif
  10
  11struct child_to_clean {
  12        pid_t pid;
  13        struct child_to_clean *next;
  14};
  15static struct child_to_clean *children_to_clean;
  16static int installed_child_cleanup_handler;
  17
  18static void cleanup_children(int sig)
  19{
  20        while (children_to_clean) {
  21                struct child_to_clean *p = children_to_clean;
  22                children_to_clean = p->next;
  23                kill(p->pid, sig);
  24                free(p);
  25        }
  26}
  27
  28static void cleanup_children_on_signal(int sig)
  29{
  30        cleanup_children(sig);
  31        sigchain_pop(sig);
  32        raise(sig);
  33}
  34
  35static void cleanup_children_on_exit(void)
  36{
  37        cleanup_children(SIGTERM);
  38}
  39
  40static void mark_child_for_cleanup(pid_t pid)
  41{
  42        struct child_to_clean *p = xmalloc(sizeof(*p));
  43        p->pid = pid;
  44        p->next = children_to_clean;
  45        children_to_clean = p;
  46
  47        if (!installed_child_cleanup_handler) {
  48                atexit(cleanup_children_on_exit);
  49                sigchain_push_common(cleanup_children_on_signal);
  50                installed_child_cleanup_handler = 1;
  51        }
  52}
  53
  54static void clear_child_for_cleanup(pid_t pid)
  55{
  56        struct child_to_clean **last, *p;
  57
  58        last = &children_to_clean;
  59        for (p = children_to_clean; p; p = p->next) {
  60                if (p->pid == pid) {
  61                        *last = p->next;
  62                        free(p);
  63                        return;
  64                }
  65        }
  66}
  67
  68static inline void close_pair(int fd[2])
  69{
  70        close(fd[0]);
  71        close(fd[1]);
  72}
  73
  74#ifndef WIN32
  75static inline void dup_devnull(int to)
  76{
  77        int fd = open("/dev/null", O_RDWR);
  78        dup2(fd, to);
  79        close(fd);
  80}
  81#endif
  82
  83static char *locate_in_PATH(const char *file)
  84{
  85        const char *p = getenv("PATH");
  86        struct strbuf buf = STRBUF_INIT;
  87
  88        if (!p || !*p)
  89                return NULL;
  90
  91        while (1) {
  92                const char *end = strchrnul(p, ':');
  93
  94                strbuf_reset(&buf);
  95
  96                /* POSIX specifies an empty entry as the current directory. */
  97                if (end != p) {
  98                        strbuf_add(&buf, p, end - p);
  99                        strbuf_addch(&buf, '/');
 100                }
 101                strbuf_addstr(&buf, file);
 102
 103                if (!access(buf.buf, F_OK))
 104                        return strbuf_detach(&buf, NULL);
 105
 106                if (!*end)
 107                        break;
 108                p = end + 1;
 109        }
 110
 111        strbuf_release(&buf);
 112        return NULL;
 113}
 114
 115static int exists_in_PATH(const char *file)
 116{
 117        char *r = locate_in_PATH(file);
 118        free(r);
 119        return r != NULL;
 120}
 121
 122int sane_execvp(const char *file, char * const argv[])
 123{
 124        if (!execvp(file, argv))
 125                return 0; /* cannot happen ;-) */
 126
 127        /*
 128         * When a command can't be found because one of the directories
 129         * listed in $PATH is unsearchable, execvp reports EACCES, but
 130         * careful usability testing (read: analysis of occasional bug
 131         * reports) reveals that "No such file or directory" is more
 132         * intuitive.
 133         *
 134         * We avoid commands with "/", because execvp will not do $PATH
 135         * lookups in that case.
 136         *
 137         * The reassignment of EACCES to errno looks like a no-op below,
 138         * but we need to protect against exists_in_PATH overwriting errno.
 139         */
 140        if (errno == EACCES && !strchr(file, '/'))
 141                errno = exists_in_PATH(file) ? EACCES : ENOENT;
 142        return -1;
 143}
 144
 145static const char **prepare_shell_cmd(const char **argv)
 146{
 147        int argc, nargc = 0;
 148        const char **nargv;
 149
 150        for (argc = 0; argv[argc]; argc++)
 151                ; /* just counting */
 152        /* +1 for NULL, +3 for "sh -c" plus extra $0 */
 153        nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
 154
 155        if (argc < 1)
 156                die("BUG: shell command is empty");
 157
 158        if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 159                nargv[nargc++] = SHELL_PATH;
 160                nargv[nargc++] = "-c";
 161
 162                if (argc < 2)
 163                        nargv[nargc++] = argv[0];
 164                else {
 165                        struct strbuf arg0 = STRBUF_INIT;
 166                        strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 167                        nargv[nargc++] = strbuf_detach(&arg0, NULL);
 168                }
 169        }
 170
 171        for (argc = 0; argv[argc]; argc++)
 172                nargv[nargc++] = argv[argc];
 173        nargv[nargc] = NULL;
 174
 175        return nargv;
 176}
 177
 178#ifndef WIN32
 179static int execv_shell_cmd(const char **argv)
 180{
 181        const char **nargv = prepare_shell_cmd(argv);
 182        trace_argv_printf(nargv, "trace: exec:");
 183        sane_execvp(nargv[0], (char **)nargv);
 184        free(nargv);
 185        return -1;
 186}
 187#endif
 188
 189#ifndef WIN32
 190static int child_err = 2;
 191static int child_notifier = -1;
 192
 193static void notify_parent(void)
 194{
 195        /*
 196         * execvp failed.  If possible, we'd like to let start_command
 197         * know, so failures like ENOENT can be handled right away; but
 198         * otherwise, finish_command will still report the error.
 199         */
 200        xwrite(child_notifier, "", 1);
 201}
 202
 203static NORETURN void die_child(const char *err, va_list params)
 204{
 205        vwritef(child_err, "fatal: ", err, params);
 206        exit(128);
 207}
 208
 209static void error_child(const char *err, va_list params)
 210{
 211        vwritef(child_err, "error: ", err, params);
 212}
 213#endif
 214
 215static inline void set_cloexec(int fd)
 216{
 217        int flags = fcntl(fd, F_GETFD);
 218        if (flags >= 0)
 219                fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 220}
 221
 222static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 223{
 224        int status, code = -1;
 225        pid_t waiting;
 226        int failed_errno = 0;
 227
 228        while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 229                ;       /* nothing */
 230
 231        if (waiting < 0) {
 232                failed_errno = errno;
 233                error("waitpid for %s failed: %s", argv0, strerror(errno));
 234        } else if (waiting != pid) {
 235                error("waitpid is confused (%s)", argv0);
 236        } else if (WIFSIGNALED(status)) {
 237                code = WTERMSIG(status);
 238                error("%s died of signal %d", argv0, code);
 239                /*
 240                 * This return value is chosen so that code & 0xff
 241                 * mimics the exit code that a POSIX shell would report for
 242                 * a program that died from this signal.
 243                 */
 244                code -= 128;
 245        } else if (WIFEXITED(status)) {
 246                code = WEXITSTATUS(status);
 247                /*
 248                 * Convert special exit code when execvp failed.
 249                 */
 250                if (code == 127) {
 251                        code = -1;
 252                        failed_errno = ENOENT;
 253                }
 254        } else {
 255                error("waitpid is confused (%s)", argv0);
 256        }
 257
 258        clear_child_for_cleanup(pid);
 259
 260        errno = failed_errno;
 261        return code;
 262}
 263
 264int start_command(struct child_process *cmd)
 265{
 266        int need_in, need_out, need_err;
 267        int fdin[2], fdout[2], fderr[2];
 268        int failed_errno = failed_errno;
 269
 270        /*
 271         * In case of errors we must keep the promise to close FDs
 272         * that have been passed in via ->in and ->out.
 273         */
 274
 275        need_in = !cmd->no_stdin && cmd->in < 0;
 276        if (need_in) {
 277                if (pipe(fdin) < 0) {
 278                        failed_errno = errno;
 279                        if (cmd->out > 0)
 280                                close(cmd->out);
 281                        goto fail_pipe;
 282                }
 283                cmd->in = fdin[1];
 284        }
 285
 286        need_out = !cmd->no_stdout
 287                && !cmd->stdout_to_stderr
 288                && cmd->out < 0;
 289        if (need_out) {
 290                if (pipe(fdout) < 0) {
 291                        failed_errno = errno;
 292                        if (need_in)
 293                                close_pair(fdin);
 294                        else if (cmd->in)
 295                                close(cmd->in);
 296                        goto fail_pipe;
 297                }
 298                cmd->out = fdout[0];
 299        }
 300
 301        need_err = !cmd->no_stderr && cmd->err < 0;
 302        if (need_err) {
 303                if (pipe(fderr) < 0) {
 304                        failed_errno = errno;
 305                        if (need_in)
 306                                close_pair(fdin);
 307                        else if (cmd->in)
 308                                close(cmd->in);
 309                        if (need_out)
 310                                close_pair(fdout);
 311                        else if (cmd->out)
 312                                close(cmd->out);
 313fail_pipe:
 314                        error("cannot create pipe for %s: %s",
 315                                cmd->argv[0], strerror(failed_errno));
 316                        errno = failed_errno;
 317                        return -1;
 318                }
 319                cmd->err = fderr[0];
 320        }
 321
 322        trace_argv_printf(cmd->argv, "trace: run_command:");
 323        fflush(NULL);
 324
 325#ifndef WIN32
 326{
 327        int notify_pipe[2];
 328        if (pipe(notify_pipe))
 329                notify_pipe[0] = notify_pipe[1] = -1;
 330
 331        cmd->pid = fork();
 332        if (!cmd->pid) {
 333                /*
 334                 * Redirect the channel to write syscall error messages to
 335                 * before redirecting the process's stderr so that all die()
 336                 * in subsequent call paths use the parent's stderr.
 337                 */
 338                if (cmd->no_stderr || need_err) {
 339                        child_err = dup(2);
 340                        set_cloexec(child_err);
 341                }
 342                set_die_routine(die_child);
 343                set_error_routine(error_child);
 344
 345                close(notify_pipe[0]);
 346                set_cloexec(notify_pipe[1]);
 347                child_notifier = notify_pipe[1];
 348                atexit(notify_parent);
 349
 350                if (cmd->no_stdin)
 351                        dup_devnull(0);
 352                else if (need_in) {
 353                        dup2(fdin[0], 0);
 354                        close_pair(fdin);
 355                } else if (cmd->in) {
 356                        dup2(cmd->in, 0);
 357                        close(cmd->in);
 358                }
 359
 360                if (cmd->no_stderr)
 361                        dup_devnull(2);
 362                else if (need_err) {
 363                        dup2(fderr[1], 2);
 364                        close_pair(fderr);
 365                } else if (cmd->err > 1) {
 366                        dup2(cmd->err, 2);
 367                        close(cmd->err);
 368                }
 369
 370                if (cmd->no_stdout)
 371                        dup_devnull(1);
 372                else if (cmd->stdout_to_stderr)
 373                        dup2(2, 1);
 374                else if (need_out) {
 375                        dup2(fdout[1], 1);
 376                        close_pair(fdout);
 377                } else if (cmd->out > 1) {
 378                        dup2(cmd->out, 1);
 379                        close(cmd->out);
 380                }
 381
 382                if (cmd->dir && chdir(cmd->dir))
 383                        die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 384                            cmd->dir);
 385                if (cmd->env) {
 386                        for (; *cmd->env; cmd->env++) {
 387                                if (strchr(*cmd->env, '='))
 388                                        putenv((char *)*cmd->env);
 389                                else
 390                                        unsetenv(*cmd->env);
 391                        }
 392                }
 393                if (cmd->preexec_cb) {
 394                        /*
 395                         * We cannot predict what the pre-exec callback does.
 396                         * Forgo parent notification.
 397                         */
 398                        close(child_notifier);
 399                        child_notifier = -1;
 400
 401                        cmd->preexec_cb();
 402                }
 403                if (cmd->git_cmd) {
 404                        execv_git_cmd(cmd->argv);
 405                } else if (cmd->use_shell) {
 406                        execv_shell_cmd(cmd->argv);
 407                } else {
 408                        sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 409                }
 410                if (errno == ENOENT) {
 411                        if (!cmd->silent_exec_failure)
 412                                error("cannot run %s: %s", cmd->argv[0],
 413                                        strerror(ENOENT));
 414                        exit(127);
 415                } else {
 416                        die_errno("cannot exec '%s'", cmd->argv[0]);
 417                }
 418        }
 419        if (cmd->pid < 0)
 420                error("cannot fork() for %s: %s", cmd->argv[0],
 421                        strerror(failed_errno = errno));
 422        else if (cmd->clean_on_exit)
 423                mark_child_for_cleanup(cmd->pid);
 424
 425        /*
 426         * Wait for child's execvp. If the execvp succeeds (or if fork()
 427         * failed), EOF is seen immediately by the parent. Otherwise, the
 428         * child process sends a single byte.
 429         * Note that use of this infrastructure is completely advisory,
 430         * therefore, we keep error checks minimal.
 431         */
 432        close(notify_pipe[1]);
 433        if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 434                /*
 435                 * At this point we know that fork() succeeded, but execvp()
 436                 * failed. Errors have been reported to our stderr.
 437                 */
 438                wait_or_whine(cmd->pid, cmd->argv[0],
 439                              cmd->silent_exec_failure);
 440                failed_errno = errno;
 441                cmd->pid = -1;
 442        }
 443        close(notify_pipe[0]);
 444
 445}
 446#else
 447{
 448        int fhin = 0, fhout = 1, fherr = 2;
 449        const char **sargv = cmd->argv;
 450        char **env = environ;
 451
 452        if (cmd->no_stdin)
 453                fhin = open("/dev/null", O_RDWR);
 454        else if (need_in)
 455                fhin = dup(fdin[0]);
 456        else if (cmd->in)
 457                fhin = dup(cmd->in);
 458
 459        if (cmd->no_stderr)
 460                fherr = open("/dev/null", O_RDWR);
 461        else if (need_err)
 462                fherr = dup(fderr[1]);
 463        else if (cmd->err > 2)
 464                fherr = dup(cmd->err);
 465
 466        if (cmd->no_stdout)
 467                fhout = open("/dev/null", O_RDWR);
 468        else if (cmd->stdout_to_stderr)
 469                fhout = dup(fherr);
 470        else if (need_out)
 471                fhout = dup(fdout[1]);
 472        else if (cmd->out > 1)
 473                fhout = dup(cmd->out);
 474
 475        if (cmd->env)
 476                env = make_augmented_environ(cmd->env);
 477
 478        if (cmd->git_cmd) {
 479                cmd->argv = prepare_git_cmd(cmd->argv);
 480        } else if (cmd->use_shell) {
 481                cmd->argv = prepare_shell_cmd(cmd->argv);
 482        }
 483
 484        cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 485                                  fhin, fhout, fherr);
 486        failed_errno = errno;
 487        if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 488                error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 489        if (cmd->clean_on_exit && cmd->pid >= 0)
 490                mark_child_for_cleanup(cmd->pid);
 491
 492        if (cmd->env)
 493                free_environ(env);
 494        if (cmd->git_cmd)
 495                free(cmd->argv);
 496
 497        cmd->argv = sargv;
 498        if (fhin != 0)
 499                close(fhin);
 500        if (fhout != 1)
 501                close(fhout);
 502        if (fherr != 2)
 503                close(fherr);
 504}
 505#endif
 506
 507        if (cmd->pid < 0) {
 508                if (need_in)
 509                        close_pair(fdin);
 510                else if (cmd->in)
 511                        close(cmd->in);
 512                if (need_out)
 513                        close_pair(fdout);
 514                else if (cmd->out)
 515                        close(cmd->out);
 516                if (need_err)
 517                        close_pair(fderr);
 518                else if (cmd->err)
 519                        close(cmd->err);
 520                errno = failed_errno;
 521                return -1;
 522        }
 523
 524        if (need_in)
 525                close(fdin[0]);
 526        else if (cmd->in)
 527                close(cmd->in);
 528
 529        if (need_out)
 530                close(fdout[1]);
 531        else if (cmd->out)
 532                close(cmd->out);
 533
 534        if (need_err)
 535                close(fderr[1]);
 536        else if (cmd->err)
 537                close(cmd->err);
 538
 539        return 0;
 540}
 541
 542int finish_command(struct child_process *cmd)
 543{
 544        return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 545}
 546
 547int run_command(struct child_process *cmd)
 548{
 549        int code = start_command(cmd);
 550        if (code)
 551                return code;
 552        return finish_command(cmd);
 553}
 554
 555static void prepare_run_command_v_opt(struct child_process *cmd,
 556                                      const char **argv,
 557                                      int opt)
 558{
 559        memset(cmd, 0, sizeof(*cmd));
 560        cmd->argv = argv;
 561        cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 562        cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 563        cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 564        cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 565        cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 566        cmd->clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 567}
 568
 569int run_command_v_opt(const char **argv, int opt)
 570{
 571        struct child_process cmd;
 572        prepare_run_command_v_opt(&cmd, argv, opt);
 573        return run_command(&cmd);
 574}
 575
 576int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 577{
 578        struct child_process cmd;
 579        prepare_run_command_v_opt(&cmd, argv, opt);
 580        cmd.dir = dir;
 581        cmd.env = env;
 582        return run_command(&cmd);
 583}
 584
 585#ifndef NO_PTHREADS
 586static pthread_t main_thread;
 587static int main_thread_set;
 588static pthread_key_t async_key;
 589
 590static void *run_thread(void *data)
 591{
 592        struct async *async = data;
 593        intptr_t ret;
 594
 595        pthread_setspecific(async_key, async);
 596        ret = async->proc(async->proc_in, async->proc_out, async->data);
 597        return (void *)ret;
 598}
 599
 600static NORETURN void die_async(const char *err, va_list params)
 601{
 602        vreportf("fatal: ", err, params);
 603
 604        if (!pthread_equal(main_thread, pthread_self())) {
 605                struct async *async = pthread_getspecific(async_key);
 606                if (async->proc_in >= 0)
 607                        close(async->proc_in);
 608                if (async->proc_out >= 0)
 609                        close(async->proc_out);
 610                pthread_exit((void *)128);
 611        }
 612
 613        exit(128);
 614}
 615#endif
 616
 617int start_async(struct async *async)
 618{
 619        int need_in, need_out;
 620        int fdin[2], fdout[2];
 621        int proc_in, proc_out;
 622
 623        need_in = async->in < 0;
 624        if (need_in) {
 625                if (pipe(fdin) < 0) {
 626                        if (async->out > 0)
 627                                close(async->out);
 628                        return error("cannot create pipe: %s", strerror(errno));
 629                }
 630                async->in = fdin[1];
 631        }
 632
 633        need_out = async->out < 0;
 634        if (need_out) {
 635                if (pipe(fdout) < 0) {
 636                        if (need_in)
 637                                close_pair(fdin);
 638                        else if (async->in)
 639                                close(async->in);
 640                        return error("cannot create pipe: %s", strerror(errno));
 641                }
 642                async->out = fdout[0];
 643        }
 644
 645        if (need_in)
 646                proc_in = fdin[0];
 647        else if (async->in)
 648                proc_in = async->in;
 649        else
 650                proc_in = -1;
 651
 652        if (need_out)
 653                proc_out = fdout[1];
 654        else if (async->out)
 655                proc_out = async->out;
 656        else
 657                proc_out = -1;
 658
 659#ifdef NO_PTHREADS
 660        /* Flush stdio before fork() to avoid cloning buffers */
 661        fflush(NULL);
 662
 663        async->pid = fork();
 664        if (async->pid < 0) {
 665                error("fork (async) failed: %s", strerror(errno));
 666                goto error;
 667        }
 668        if (!async->pid) {
 669                if (need_in)
 670                        close(fdin[1]);
 671                if (need_out)
 672                        close(fdout[0]);
 673                exit(!!async->proc(proc_in, proc_out, async->data));
 674        }
 675
 676        mark_child_for_cleanup(async->pid);
 677
 678        if (need_in)
 679                close(fdin[0]);
 680        else if (async->in)
 681                close(async->in);
 682
 683        if (need_out)
 684                close(fdout[1]);
 685        else if (async->out)
 686                close(async->out);
 687#else
 688        if (!main_thread_set) {
 689                /*
 690                 * We assume that the first time that start_async is called
 691                 * it is from the main thread.
 692                 */
 693                main_thread_set = 1;
 694                main_thread = pthread_self();
 695                pthread_key_create(&async_key, NULL);
 696                set_die_routine(die_async);
 697        }
 698
 699        if (proc_in >= 0)
 700                set_cloexec(proc_in);
 701        if (proc_out >= 0)
 702                set_cloexec(proc_out);
 703        async->proc_in = proc_in;
 704        async->proc_out = proc_out;
 705        {
 706                int err = pthread_create(&async->tid, NULL, run_thread, async);
 707                if (err) {
 708                        error("cannot create thread: %s", strerror(err));
 709                        goto error;
 710                }
 711        }
 712#endif
 713        return 0;
 714
 715error:
 716        if (need_in)
 717                close_pair(fdin);
 718        else if (async->in)
 719                close(async->in);
 720
 721        if (need_out)
 722                close_pair(fdout);
 723        else if (async->out)
 724                close(async->out);
 725        return -1;
 726}
 727
 728int finish_async(struct async *async)
 729{
 730#ifdef NO_PTHREADS
 731        return wait_or_whine(async->pid, "child process", 0);
 732#else
 733        void *ret = (void *)(intptr_t)(-1);
 734
 735        if (pthread_join(async->tid, &ret))
 736                error("pthread_join failed");
 737        return (int)(intptr_t)ret;
 738#endif
 739}
 740
 741int run_hook(const char *index_file, const char *name, ...)
 742{
 743        struct child_process hook;
 744        struct argv_array argv = ARGV_ARRAY_INIT;
 745        const char *p, *env[2];
 746        char index[PATH_MAX];
 747        va_list args;
 748        int ret;
 749
 750        if (access(git_path("hooks/%s", name), X_OK) < 0)
 751                return 0;
 752
 753        va_start(args, name);
 754        argv_array_push(&argv, git_path("hooks/%s", name));
 755        while ((p = va_arg(args, const char *)))
 756                argv_array_push(&argv, p);
 757        va_end(args);
 758
 759        memset(&hook, 0, sizeof(hook));
 760        hook.argv = argv.argv;
 761        hook.no_stdin = 1;
 762        hook.stdout_to_stderr = 1;
 763        if (index_file) {
 764                snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 765                env[0] = index;
 766                env[1] = NULL;
 767                hook.env = env;
 768        }
 769
 770        ret = run_command(&hook);
 771        argv_array_clear(&argv);
 772        return ret;
 773}