Andrew's git / gitweb.git / run-command.c
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run-command.con commit pager: drop "wait for output to run less" hack (e8320f3)
   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#ifndef WIN32
 160                nargv[nargc++] = SHELL_PATH;
 161#else
 162                nargv[nargc++] = "sh";
 163#endif
 164                nargv[nargc++] = "-c";
 165
 166                if (argc < 2)
 167                        nargv[nargc++] = argv[0];
 168                else {
 169                        struct strbuf arg0 = STRBUF_INIT;
 170                        strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 171                        nargv[nargc++] = strbuf_detach(&arg0, NULL);
 172                }
 173        }
 174
 175        for (argc = 0; argv[argc]; argc++)
 176                nargv[nargc++] = argv[argc];
 177        nargv[nargc] = NULL;
 178
 179        return nargv;
 180}
 181
 182#ifndef WIN32
 183static int execv_shell_cmd(const char **argv)
 184{
 185        const char **nargv = prepare_shell_cmd(argv);
 186        trace_argv_printf(nargv, "trace: exec:");
 187        sane_execvp(nargv[0], (char **)nargv);
 188        free(nargv);
 189        return -1;
 190}
 191#endif
 192
 193#ifndef WIN32
 194static int child_err = 2;
 195static int child_notifier = -1;
 196
 197static void notify_parent(void)
 198{
 199        /*
 200         * execvp failed.  If possible, we'd like to let start_command
 201         * know, so failures like ENOENT can be handled right away; but
 202         * otherwise, finish_command will still report the error.
 203         */
 204        xwrite(child_notifier, "", 1);
 205}
 206
 207static NORETURN void die_child(const char *err, va_list params)
 208{
 209        vwritef(child_err, "fatal: ", err, params);
 210        exit(128);
 211}
 212
 213static void error_child(const char *err, va_list params)
 214{
 215        vwritef(child_err, "error: ", err, params);
 216}
 217#endif
 218
 219static inline void set_cloexec(int fd)
 220{
 221        int flags = fcntl(fd, F_GETFD);
 222        if (flags >= 0)
 223                fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 224}
 225
 226static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 227{
 228        int status, code = -1;
 229        pid_t waiting;
 230        int failed_errno = 0;
 231
 232        while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 233                ;       /* nothing */
 234
 235        if (waiting < 0) {
 236                failed_errno = errno;
 237                error("waitpid for %s failed: %s", argv0, strerror(errno));
 238        } else if (waiting != pid) {
 239                error("waitpid is confused (%s)", argv0);
 240        } else if (WIFSIGNALED(status)) {
 241                code = WTERMSIG(status);
 242                error("%s died of signal %d", argv0, code);
 243                /*
 244                 * This return value is chosen so that code & 0xff
 245                 * mimics the exit code that a POSIX shell would report for
 246                 * a program that died from this signal.
 247                 */
 248                code -= 128;
 249        } else if (WIFEXITED(status)) {
 250                code = WEXITSTATUS(status);
 251                /*
 252                 * Convert special exit code when execvp failed.
 253                 */
 254                if (code == 127) {
 255                        code = -1;
 256                        failed_errno = ENOENT;
 257                }
 258        } else {
 259                error("waitpid is confused (%s)", argv0);
 260        }
 261
 262        clear_child_for_cleanup(pid);
 263
 264        errno = failed_errno;
 265        return code;
 266}
 267
 268int start_command(struct child_process *cmd)
 269{
 270        int need_in, need_out, need_err;
 271        int fdin[2], fdout[2], fderr[2];
 272        int failed_errno = failed_errno;
 273
 274        /*
 275         * In case of errors we must keep the promise to close FDs
 276         * that have been passed in via ->in and ->out.
 277         */
 278
 279        need_in = !cmd->no_stdin && cmd->in < 0;
 280        if (need_in) {
 281                if (pipe(fdin) < 0) {
 282                        failed_errno = errno;
 283                        if (cmd->out > 0)
 284                                close(cmd->out);
 285                        goto fail_pipe;
 286                }
 287                cmd->in = fdin[1];
 288        }
 289
 290        need_out = !cmd->no_stdout
 291                && !cmd->stdout_to_stderr
 292                && cmd->out < 0;
 293        if (need_out) {
 294                if (pipe(fdout) < 0) {
 295                        failed_errno = errno;
 296                        if (need_in)
 297                                close_pair(fdin);
 298                        else if (cmd->in)
 299                                close(cmd->in);
 300                        goto fail_pipe;
 301                }
 302                cmd->out = fdout[0];
 303        }
 304
 305        need_err = !cmd->no_stderr && cmd->err < 0;
 306        if (need_err) {
 307                if (pipe(fderr) < 0) {
 308                        failed_errno = errno;
 309                        if (need_in)
 310                                close_pair(fdin);
 311                        else if (cmd->in)
 312                                close(cmd->in);
 313                        if (need_out)
 314                                close_pair(fdout);
 315                        else if (cmd->out)
 316                                close(cmd->out);
 317fail_pipe:
 318                        error("cannot create pipe for %s: %s",
 319                                cmd->argv[0], strerror(failed_errno));
 320                        errno = failed_errno;
 321                        return -1;
 322                }
 323                cmd->err = fderr[0];
 324        }
 325
 326        trace_argv_printf(cmd->argv, "trace: run_command:");
 327        fflush(NULL);
 328
 329#ifndef WIN32
 330{
 331        int notify_pipe[2];
 332        if (pipe(notify_pipe))
 333                notify_pipe[0] = notify_pipe[1] = -1;
 334
 335        cmd->pid = fork();
 336        if (!cmd->pid) {
 337                /*
 338                 * Redirect the channel to write syscall error messages to
 339                 * before redirecting the process's stderr so that all die()
 340                 * in subsequent call paths use the parent's stderr.
 341                 */
 342                if (cmd->no_stderr || need_err) {
 343                        child_err = dup(2);
 344                        set_cloexec(child_err);
 345                }
 346                set_die_routine(die_child);
 347                set_error_routine(error_child);
 348
 349                close(notify_pipe[0]);
 350                set_cloexec(notify_pipe[1]);
 351                child_notifier = notify_pipe[1];
 352                atexit(notify_parent);
 353
 354                if (cmd->no_stdin)
 355                        dup_devnull(0);
 356                else if (need_in) {
 357                        dup2(fdin[0], 0);
 358                        close_pair(fdin);
 359                } else if (cmd->in) {
 360                        dup2(cmd->in, 0);
 361                        close(cmd->in);
 362                }
 363
 364                if (cmd->no_stderr)
 365                        dup_devnull(2);
 366                else if (need_err) {
 367                        dup2(fderr[1], 2);
 368                        close_pair(fderr);
 369                } else if (cmd->err > 1) {
 370                        dup2(cmd->err, 2);
 371                        close(cmd->err);
 372                }
 373
 374                if (cmd->no_stdout)
 375                        dup_devnull(1);
 376                else if (cmd->stdout_to_stderr)
 377                        dup2(2, 1);
 378                else if (need_out) {
 379                        dup2(fdout[1], 1);
 380                        close_pair(fdout);
 381                } else if (cmd->out > 1) {
 382                        dup2(cmd->out, 1);
 383                        close(cmd->out);
 384                }
 385
 386                if (cmd->dir && chdir(cmd->dir))
 387                        die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 388                            cmd->dir);
 389                if (cmd->env) {
 390                        for (; *cmd->env; cmd->env++) {
 391                                if (strchr(*cmd->env, '='))
 392                                        putenv((char *)*cmd->env);
 393                                else
 394                                        unsetenv(*cmd->env);
 395                        }
 396                }
 397                if (cmd->git_cmd) {
 398                        execv_git_cmd(cmd->argv);
 399                } else if (cmd->use_shell) {
 400                        execv_shell_cmd(cmd->argv);
 401                } else {
 402                        sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 403                }
 404                if (errno == ENOENT) {
 405                        if (!cmd->silent_exec_failure)
 406                                error("cannot run %s: %s", cmd->argv[0],
 407                                        strerror(ENOENT));
 408                        exit(127);
 409                } else {
 410                        die_errno("cannot exec '%s'", cmd->argv[0]);
 411                }
 412        }
 413        if (cmd->pid < 0)
 414                error("cannot fork() for %s: %s", cmd->argv[0],
 415                        strerror(failed_errno = errno));
 416        else if (cmd->clean_on_exit)
 417                mark_child_for_cleanup(cmd->pid);
 418
 419        /*
 420         * Wait for child's execvp. If the execvp succeeds (or if fork()
 421         * failed), EOF is seen immediately by the parent. Otherwise, the
 422         * child process sends a single byte.
 423         * Note that use of this infrastructure is completely advisory,
 424         * therefore, we keep error checks minimal.
 425         */
 426        close(notify_pipe[1]);
 427        if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 428                /*
 429                 * At this point we know that fork() succeeded, but execvp()
 430                 * failed. Errors have been reported to our stderr.
 431                 */
 432                wait_or_whine(cmd->pid, cmd->argv[0],
 433                              cmd->silent_exec_failure);
 434                failed_errno = errno;
 435                cmd->pid = -1;
 436        }
 437        close(notify_pipe[0]);
 438
 439}
 440#else
 441{
 442        int fhin = 0, fhout = 1, fherr = 2;
 443        const char **sargv = cmd->argv;
 444        char **env = environ;
 445
 446        if (cmd->no_stdin)
 447                fhin = open("/dev/null", O_RDWR);
 448        else if (need_in)
 449                fhin = dup(fdin[0]);
 450        else if (cmd->in)
 451                fhin = dup(cmd->in);
 452
 453        if (cmd->no_stderr)
 454                fherr = open("/dev/null", O_RDWR);
 455        else if (need_err)
 456                fherr = dup(fderr[1]);
 457        else if (cmd->err > 2)
 458                fherr = dup(cmd->err);
 459
 460        if (cmd->no_stdout)
 461                fhout = open("/dev/null", O_RDWR);
 462        else if (cmd->stdout_to_stderr)
 463                fhout = dup(fherr);
 464        else if (need_out)
 465                fhout = dup(fdout[1]);
 466        else if (cmd->out > 1)
 467                fhout = dup(cmd->out);
 468
 469        if (cmd->env)
 470                env = make_augmented_environ(cmd->env);
 471
 472        if (cmd->git_cmd) {
 473                cmd->argv = prepare_git_cmd(cmd->argv);
 474        } else if (cmd->use_shell) {
 475                cmd->argv = prepare_shell_cmd(cmd->argv);
 476        }
 477
 478        cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 479                                  fhin, fhout, fherr);
 480        failed_errno = errno;
 481        if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 482                error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 483        if (cmd->clean_on_exit && cmd->pid >= 0)
 484                mark_child_for_cleanup(cmd->pid);
 485
 486        if (cmd->env)
 487                free_environ(env);
 488        if (cmd->git_cmd)
 489                free(cmd->argv);
 490
 491        cmd->argv = sargv;
 492        if (fhin != 0)
 493                close(fhin);
 494        if (fhout != 1)
 495                close(fhout);
 496        if (fherr != 2)
 497                close(fherr);
 498}
 499#endif
 500
 501        if (cmd->pid < 0) {
 502                if (need_in)
 503                        close_pair(fdin);
 504                else if (cmd->in)
 505                        close(cmd->in);
 506                if (need_out)
 507                        close_pair(fdout);
 508                else if (cmd->out)
 509                        close(cmd->out);
 510                if (need_err)
 511                        close_pair(fderr);
 512                else if (cmd->err)
 513                        close(cmd->err);
 514                errno = failed_errno;
 515                return -1;
 516        }
 517
 518        if (need_in)
 519                close(fdin[0]);
 520        else if (cmd->in)
 521                close(cmd->in);
 522
 523        if (need_out)
 524                close(fdout[1]);
 525        else if (cmd->out)
 526                close(cmd->out);
 527
 528        if (need_err)
 529                close(fderr[1]);
 530        else if (cmd->err)
 531                close(cmd->err);
 532
 533        return 0;
 534}
 535
 536int finish_command(struct child_process *cmd)
 537{
 538        return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 539}
 540
 541int run_command(struct child_process *cmd)
 542{
 543        int code = start_command(cmd);
 544        if (code)
 545                return code;
 546        return finish_command(cmd);
 547}
 548
 549static void prepare_run_command_v_opt(struct child_process *cmd,
 550                                      const char **argv,
 551                                      int opt)
 552{
 553        memset(cmd, 0, sizeof(*cmd));
 554        cmd->argv = argv;
 555        cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 556        cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 557        cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 558        cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 559        cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 560        cmd->clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 561}
 562
 563int run_command_v_opt(const char **argv, int opt)
 564{
 565        struct child_process cmd;
 566        prepare_run_command_v_opt(&cmd, argv, opt);
 567        return run_command(&cmd);
 568}
 569
 570int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 571{
 572        struct child_process cmd;
 573        prepare_run_command_v_opt(&cmd, argv, opt);
 574        cmd.dir = dir;
 575        cmd.env = env;
 576        return run_command(&cmd);
 577}
 578
 579#ifndef NO_PTHREADS
 580static pthread_t main_thread;
 581static int main_thread_set;
 582static pthread_key_t async_key;
 583
 584static void *run_thread(void *data)
 585{
 586        struct async *async = data;
 587        intptr_t ret;
 588
 589        pthread_setspecific(async_key, async);
 590        ret = async->proc(async->proc_in, async->proc_out, async->data);
 591        return (void *)ret;
 592}
 593
 594static NORETURN void die_async(const char *err, va_list params)
 595{
 596        vreportf("fatal: ", err, params);
 597
 598        if (!pthread_equal(main_thread, pthread_self())) {
 599                struct async *async = pthread_getspecific(async_key);
 600                if (async->proc_in >= 0)
 601                        close(async->proc_in);
 602                if (async->proc_out >= 0)
 603                        close(async->proc_out);
 604                pthread_exit((void *)128);
 605        }
 606
 607        exit(128);
 608}
 609#endif
 610
 611int start_async(struct async *async)
 612{
 613        int need_in, need_out;
 614        int fdin[2], fdout[2];
 615        int proc_in, proc_out;
 616
 617        need_in = async->in < 0;
 618        if (need_in) {
 619                if (pipe(fdin) < 0) {
 620                        if (async->out > 0)
 621                                close(async->out);
 622                        return error("cannot create pipe: %s", strerror(errno));
 623                }
 624                async->in = fdin[1];
 625        }
 626
 627        need_out = async->out < 0;
 628        if (need_out) {
 629                if (pipe(fdout) < 0) {
 630                        if (need_in)
 631                                close_pair(fdin);
 632                        else if (async->in)
 633                                close(async->in);
 634                        return error("cannot create pipe: %s", strerror(errno));
 635                }
 636                async->out = fdout[0];
 637        }
 638
 639        if (need_in)
 640                proc_in = fdin[0];
 641        else if (async->in)
 642                proc_in = async->in;
 643        else
 644                proc_in = -1;
 645
 646        if (need_out)
 647                proc_out = fdout[1];
 648        else if (async->out)
 649                proc_out = async->out;
 650        else
 651                proc_out = -1;
 652
 653#ifdef NO_PTHREADS
 654        /* Flush stdio before fork() to avoid cloning buffers */
 655        fflush(NULL);
 656
 657        async->pid = fork();
 658        if (async->pid < 0) {
 659                error("fork (async) failed: %s", strerror(errno));
 660                goto error;
 661        }
 662        if (!async->pid) {
 663                if (need_in)
 664                        close(fdin[1]);
 665                if (need_out)
 666                        close(fdout[0]);
 667                exit(!!async->proc(proc_in, proc_out, async->data));
 668        }
 669
 670        mark_child_for_cleanup(async->pid);
 671
 672        if (need_in)
 673                close(fdin[0]);
 674        else if (async->in)
 675                close(async->in);
 676
 677        if (need_out)
 678                close(fdout[1]);
 679        else if (async->out)
 680                close(async->out);
 681#else
 682        if (!main_thread_set) {
 683                /*
 684                 * We assume that the first time that start_async is called
 685                 * it is from the main thread.
 686                 */
 687                main_thread_set = 1;
 688                main_thread = pthread_self();
 689                pthread_key_create(&async_key, NULL);
 690                set_die_routine(die_async);
 691        }
 692
 693        if (proc_in >= 0)
 694                set_cloexec(proc_in);
 695        if (proc_out >= 0)
 696                set_cloexec(proc_out);
 697        async->proc_in = proc_in;
 698        async->proc_out = proc_out;
 699        {
 700                int err = pthread_create(&async->tid, NULL, run_thread, async);
 701                if (err) {
 702                        error("cannot create thread: %s", strerror(err));
 703                        goto error;
 704                }
 705        }
 706#endif
 707        return 0;
 708
 709error:
 710        if (need_in)
 711                close_pair(fdin);
 712        else if (async->in)
 713                close(async->in);
 714
 715        if (need_out)
 716                close_pair(fdout);
 717        else if (async->out)
 718                close(async->out);
 719        return -1;
 720}
 721
 722int finish_async(struct async *async)
 723{
 724#ifdef NO_PTHREADS
 725        return wait_or_whine(async->pid, "child process", 0);
 726#else
 727        void *ret = (void *)(intptr_t)(-1);
 728
 729        if (pthread_join(async->tid, &ret))
 730                error("pthread_join failed");
 731        return (int)(intptr_t)ret;
 732#endif
 733}
 734
 735int run_hook(const char *index_file, const char *name, ...)
 736{
 737        struct child_process hook;
 738        struct argv_array argv = ARGV_ARRAY_INIT;
 739        const char *p, *env[2];
 740        char index[PATH_MAX];
 741        va_list args;
 742        int ret;
 743
 744        if (access(git_path("hooks/%s", name), X_OK) < 0)
 745                return 0;
 746
 747        va_start(args, name);
 748        argv_array_push(&argv, git_path("hooks/%s", name));
 749        while ((p = va_arg(args, const char *)))
 750                argv_array_push(&argv, p);
 751        va_end(args);
 752
 753        memset(&hook, 0, sizeof(hook));
 754        hook.argv = argv.argv;
 755        hook.no_stdin = 1;
 756        hook.stdout_to_stderr = 1;
 757        if (index_file) {
 758                snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 759                env[0] = index;
 760                env[1] = NULL;
 761                hook.env = env;
 762        }
 763
 764        ret = run_command(&hook);
 765        argv_array_clear(&argv);
 766        return ret;
 767}