path: root/libglusterfs/src/run.c

/*
  Copyright (c) 2008-2012 Red Hat, Inc. <http://www.redhat.com>
  This file is part of GlusterFS.

  This file is licensed to you under your choice of the GNU Lesser
  General Public License, version 3 or any later version (LGPLv3 or
  later), or the GNU General Public License, version 2 (GPLv2), in all
  cases as published by the Free Software Foundation.
*/

#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <dirent.h>
#include <assert.h>
#include <signal.h>
#include <sys/wait.h>
#include "syscall.h"

/*
 * Following defines are available for helping development:
 * RUN_STANDALONE and RUN_DO_DEMO.
 *
 * Compiling a standalone object file with no dependencies
 * on glusterfs:
 * $ cc -DRUN_STANDALONE -c run.c
 *
 * Compiling a demo program that exercises bits of run.c
 * functionality (linking to glusterfs):
 * $ cc -DRUN_DO_DEMO -orun run.c  `pkg-config --libs --cflags glusterfs-api`
 *
 * Compiling a demo program that exercises bits of run.c
 * functionality (with no dependence on glusterfs):
 *
 * $ cc -DRUN_DO_DEMO -DRUN_STANDALONE -orun run.c
 */
#if defined(RUN_STANDALONE ) || defined(RUN_DO_DEMO)
int close_fds_except (int *fdv, size_t count);
#define sys_read(f, b, c) read(f, b, c)
#define sys_write(f, b, c) write(f, b, c)
#define sys_close(f) close(f)
#define GF_CALLOC(n, s, t) calloc(n, s)
#define GF_ASSERT(cond) assert(cond)
#define GF_REALLOC(p, s) realloc(p, s)
#define GF_FREE(p) free(p)
#define gf_strdup(s) strdup(s)
#define gf_vasprintf(p, f, va) vasprintf(p, f, va)
#define gf_loglevel_t int
#define gf_msg_callingfn(dom, level, errnum, msgid, fmt, args...) printf("LOG: " fmt "\n", ##args)
#define LOG_DEBUG 0
#ifdef RUN_STANDALONE
#include <stdbool.h>
#include <sys/resource.h>
int
close_fds_except (int *fdv, size_t count)
{
        int    i            = 0;
        size_t j            = 0;
        bool   should_close = true;
        struct rlimit rl;
        int ret = -1;

        ret = getrlimit (RLIMIT_NOFILE, &rl);
        if (ret)
                return ret;

        for (i = 0; i < rl.rlim_cur; i++) {
                should_close = true;
                for (j = 0; j < count; j++) {
                        if (i == fdv[j]) {
                                should_close = false;
                                break;
                        }
                }
                if (should_close)
                        sys_close (i);
        }
        return 0;
}
#endif
#ifdef __linux__
#define GF_LINUX_HOST_OS
#endif
#else /* ! RUN_STANDALONE || RUN_DO_DEMO */
#include "glusterfs.h"
#include "common-utils.h"
#include "libglusterfs-messages.h"
#endif

#include "run.h"
void
runinit (runner_t *runner)
{
        int i = 0;

        runner->argvlen = 64;
        runner->argv = GF_CALLOC (runner->argvlen,
                                  sizeof (*runner->argv),
                                  gf_common_mt_run_argv);
        runner->runerr = runner->argv ? 0 : errno;
        runner->chpid = -1;
        for (i = 0; i < 3; i++) {
                runner->chfd[i] = -1;
                runner->chio[i] = NULL;
        }
}

FILE *
runner_chio (runner_t *runner, int fd)
{
        GF_ASSERT (fd > 0 && fd < 3);

        if ((fd > 0) && (fd < 3))
                return runner->chio[fd];

        return NULL;
}

static void
runner_insert_arg (runner_t *runner, char *arg)
{
        int i = 0;

        GF_ASSERT (arg);

        if (runner->runerr)
                return;

        for (i = 0; i < runner->argvlen; i++) {
                if (runner->argv[i] == NULL)
                        break;
        }
        GF_ASSERT (i < runner->argvlen);

        if (i == runner->argvlen - 1) {
                runner->argv = GF_REALLOC (runner->argv,
                                           runner->argvlen * 2 * sizeof (*runner->argv));
                if (!runner->argv) {
                        runner->runerr = errno;
                        return;
                }
                memset (/* "+" is aware of the type of its left side,
                         * no need to multiply with type-size */
                        runner->argv + runner->argvlen,
                        0, runner->argvlen * sizeof (*runner->argv));
                runner->argvlen *= 2;
        }

        runner->argv[i] = arg;
}

void
runner_add_arg (runner_t *runner, const char *arg)
{
        arg = gf_strdup (arg);
        if (!arg) {
                runner->runerr = errno;
                return;
        }

        runner_insert_arg (runner, (char *)arg);
}

static void
runner_va_add_args (runner_t *runner, va_list argp)
{
        const char *arg;

        while ((arg = va_arg (argp, const char *)))
                runner_add_arg (runner, arg);
}

void
runner_add_args (runner_t *runner, ...)
{
        va_list argp;

        va_start (argp, runner);
        runner_va_add_args (runner, argp);
        va_end (argp);
}

void
runner_argprintf (runner_t *runner, const char *format, ...)
{
        va_list argva;
        char *arg = NULL;
        int ret = 0;

        va_start (argva, format);
        ret = gf_vasprintf (&arg, format, argva);
        va_end (argva);

        if (ret < 0) {
                runner->runerr = errno;
                return;
        }

        runner_insert_arg (runner, arg);
}

void
runner_log (runner_t *runner, const char *dom, gf_loglevel_t lvl,
            const char *msg)
{
        char *buf = NULL;
        size_t len = 0;
        int i = 0;

        if (runner->runerr)
                return;

        for (i = 0;; i++) {
                if (runner->argv[i] == NULL)
                        break;
                len += (strlen (runner->argv[i]) + 1);
        }

        buf = GF_CALLOC (1, len + 1, gf_common_mt_run_logbuf);
        if (!buf) {
                runner->runerr = errno;
                return;
        }
        for (i = 0;; i++) {
                if (runner->argv[i] == NULL)
                        break;
                strcat (buf, runner->argv[i]);
                strcat (buf, " ");
        }
        if (len > 0)
                buf[len - 1] = '\0';

        gf_msg_callingfn (dom, lvl, 0, LG_MSG_RUNNER_LOG, "%s: %s", msg, buf);

        GF_FREE (buf);
}

void
runner_redir (runner_t *runner, int fd, int tgt_fd)
{
        GF_ASSERT (fd > 0 && fd < 3);

        if ((fd > 0) && (fd < 3))
                runner->chfd[fd] = (tgt_fd >= 0) ? tgt_fd : -2;
}

int
runner_start (runner_t *runner)
{
        int pi[3][2] = {{-1, -1}, {-1, -1}, {-1, -1}};
        int xpi[2];
        int ret = 0;
        int errno_priv = 0;
        int i = 0;
        sigset_t set;

        if (runner->runerr) {
                errno = runner->runerr;
                return -1;
        }

        GF_ASSERT (runner->argv[0]);

        /* set up a channel to child to communicate back
         * possible execve(2) failures
         */
        ret = pipe(xpi);
        if (ret != -1)
                ret = fcntl (xpi[1], F_SETFD, FD_CLOEXEC);

        for (i = 0; i < 3; i++) {
                if (runner->chfd[i] != -2)
                        continue;
                ret = pipe (pi[i]);
                if (ret != -1) {
                        runner->chio[i] = fdopen (pi[i][i ? 0 : 1], i ? "r" : "w");
                        if (!runner->chio[i])
                                ret = -1;
                }
        }

        if (ret != -1)
                runner->chpid = fork ();
        switch (runner->chpid) {
        case -1:
                errno_priv = errno;
                sys_close (xpi[0]);
                sys_close (xpi[1]);
                for (i = 0; i < 3; i++) {
                        sys_close (pi[i][0]);
                        sys_close (pi[i][1]);
                }
                errno = errno_priv;
                return -1;
        case 0:
                for (i = 0; i < 3; i++)
                        sys_close (pi[i][i ? 0 : 1]);
                sys_close (xpi[0]);
                ret = 0;

                for (i = 0; i < 3; i++) {
                        if (ret == -1)
                                break;
                        switch (runner->chfd[i]) {
                        case -1:
                                /* no redir */
                                break;
                        case -2:
                                /* redir to pipe */
                                ret = dup2 (pi[i][i ? 1 : 0], i);
                                break;
                        default:
                                /* redir to file */
                                ret = dup2 (runner->chfd[i], i);
                        }
                }

                if (ret != -1 ) {
                        int fdv[4] = {0, 1, 2, xpi[1]};

                        ret = close_fds_except(fdv, sizeof (fdv) / sizeof (*fdv));
                }

                if (ret != -1) {
                        /* save child from inheriting our signal handling */
                        sigemptyset (&set);
                        sigprocmask (SIG_SETMASK, &set, NULL);

                        execvp (runner->argv[0], runner->argv);
                }
                ret = sys_write (xpi[1], &errno, sizeof (errno));
                _exit (1);
        }

        errno_priv = errno;
        for (i = 0; i < 3; i++)
                sys_close (pi[i][i ? 1 : 0]);
        sys_close (xpi[1]);
        if (ret == -1) {
                for (i = 0; i < 3; i++) {
                        if (runner->chio[i]) {
                                fclose (runner->chio[i]);
                                runner->chio[i] = NULL;
                        }
                }
        } else {
                ret = sys_read (xpi[0], (char *)&errno_priv, sizeof (errno_priv));
                sys_close (xpi[0]);
                if (ret <= 0)
                        return 0;
                GF_ASSERT (ret == sizeof (errno_priv));
        }
        errno = errno_priv;
        return -1;
}

int
runner_end_reuse (runner_t *runner)
{
        int i = 0;
        int ret = 1;
        int chstat = 0;

        if (runner->chpid > 0) {
                if (waitpid (runner->chpid, &chstat, 0) == runner->chpid) {
                        if (WIFEXITED(chstat)) {
                                ret = WEXITSTATUS(chstat);
                        } else {
                                ret = chstat;
                        }
                }
        }

        for (i = 0; i < 3; i++) {
                if (runner->chio[i]) {
                        fclose (runner->chio[i]);
                        runner->chio[i] = NULL;
                }
        }

        return -ret;
}

int
runner_end (runner_t *runner)
{
        int i = 0;
        int ret = -1;
        char **p = NULL;

        ret = runner_end_reuse (runner);

        if (runner->argv) {
                for (p = runner->argv; *p; p++)
                        GF_FREE (*p);
                GF_FREE (runner->argv);
        }
        for (i = 0; i < 3; i++)
                sys_close (runner->chfd[i]);

        return ret;
}

static int
runner_run_generic (runner_t *runner, int (*rfin)(runner_t *runner))
{
        int ret = 0;

        ret = runner_start (runner);
        if (ret)
                goto out;
        ret = rfin (runner);

out:
        return ret;
}

int
runner_run (runner_t *runner)
{
        return runner_run_generic (runner, runner_end);
}


int
runner_run_nowait (runner_t *runner)
{
	int pid;

	pid = fork ();

	if (!pid) {
		setsid ();
		_exit (runner_start (runner));
	}

	if (pid > 0)
		runner->chpid = pid;
	return runner_end (runner);
}


int
runner_run_reuse (runner_t *runner)
{
        return runner_run_generic (runner, runner_end_reuse);
}

int
runcmd (const char *arg, ...)
{
        runner_t runner;
        va_list argp;

        runinit (&runner);
        /* ISO C requires a named argument before '...' */
        runner_add_arg (&runner, arg);

        va_start (argp, arg);
        runner_va_add_args (&runner, argp);
        va_end (argp);

        return runner_run (&runner);
}

#ifdef RUN_DO_DEMO
static void
TBANNER (const char *txt)
{
        printf("######\n### demoing %s\n", txt);
}

int
main (int argc, char **argv)
{
        runner_t runner;
        char buf[80];
        char *wdbuf;;
        int ret;
        int fd;
        long pathmax = pathconf ("/", _PC_PATH_MAX);
        struct timeval tv = {0,};
        struct timeval *tvp = NULL;
        char *tfile;

        wdbuf = malloc (pathmax);
        assert (wdbuf);
        getcwd (wdbuf, pathmax);

        TBANNER ("basic functionality: running \"echo a b\"");
        runcmd ("echo", "a", "b", NULL);

        TBANNER ("argv extension: running \"echo 1 2 ... 100\"");
        runcmd ("echo", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10",
                "11", "12", "13", "14", "15", "16", "17", "18", "19", "20",
                "21", "22", "23", "24", "25", "26", "27", "28", "29", "30",
                "31", "32", "33", "34", "35", "36", "37", "38", "39", "40",
                "41", "42", "43", "44", "45", "46", "47", "48", "49", "50",
                "51", "52", "53", "54", "55", "56", "57", "58", "59", "60",
                "61", "62", "63", "64", "65", "66", "67", "68", "69", "70",
                "71", "72", "73", "74", "75", "76", "77", "78", "79", "80",
                "81", "82", "83", "84", "85", "86", "87", "88", "89", "90",
                "91", "92", "93", "94", "95", "96", "97", "98", "99", "100", NULL);

        TBANNER ("add_args, argprintf, log, and popen-style functionality:\n"
                 "    running a multiline echo command, emit a log about it,\n"
                 "    redirect it to a pipe, read output lines\n"
                 "    and print them prefixed with \"got: \"");
        runinit (&runner);
        runner_add_args (&runner, "echo", "pid:", NULL);
        runner_argprintf (&runner, "%d\n", getpid());
        runner_add_arg (&runner, "wd:");
        runner_add_arg (&runner, wdbuf);
        runner_redir (&runner, 1, RUN_PIPE);
        runner_start (&runner);
        runner_log (&runner, "(x)", LOG_DEBUG, "starting program");
        while (fgets (buf, sizeof(buf), runner_chio (&runner, 1)))
                printf ("got: %s", buf);
        runner_end (&runner);

        TBANNER ("execve error reporting: running a non-existent command");
        ret = runcmd ("bafflavvitty", NULL);
        printf ("%d %d [%s]\n", ret, errno, strerror (errno));

        TBANNER ("output redirection: running \"echo foo\" redirected "
                 "to a temp file");
        tfile = strdup ("/tmp/foofXXXXXX");
        assert (tfile);
        fd = mkstemp (tfile);
        assert (fd != -1);
        printf ("redirecting to %s\n", tfile);
        runinit (&runner);
        runner_add_args (&runner, "echo", "foo", NULL);
        runner_redir (&runner, 1, fd);
        ret = runner_run (&runner);
        printf ("runner_run returned: %d", ret);
        if (ret != 0)
                printf (", with errno %d [%s]", errno, strerror (errno));
        putchar ('\n');

        /* sleep for seconds given as argument (0 means forever)
         * to allow investigation of post-execution state to
         * cbeck for resource leaks (eg. zombies).
         */
        if (argc > 1) {
                tv.tv_sec = strtoul (argv[1], NULL, 10);
                printf ("### %s", "sleeping for");
                if (tv.tv_sec > 0) {
                        printf (" %d seconds\n", tv.tv_sec);
                        tvp = &tv;
                } else
                        printf ("%s\n", "ever");
                select (0, 0, 0, 0, tvp);
        }

        return 0;
}
#endif