systemd/src/udev-event.c

/*
 * Copyright (C) 2003-2010 Kay Sievers <kay.sievers@vrfy.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <stdio.h>
#include <stddef.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/prctl.h>
#include <sys/poll.h>
#include <sys/epoll.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/signalfd.h>
#include <linux/sockios.h>

#include "udev.h"

struct udev_event *udev_event_new(struct udev_device *dev)
{
        struct udev *udev = udev_device_get_udev(dev);
        struct udev_event *event;

        event = calloc(1, sizeof(struct udev_event));
        if (event == NULL)
                return NULL;
        event->dev = dev;
        event->udev = udev;
        udev_list_init(udev, &event->run_list, false);
        event->fd_signal = -1;
        event->birth_usec = now_usec();
        event->timeout_usec = 30 * 1000 * 1000;
        dbg(event->udev, "allocated event %p\n", event);
        return event;
}

void udev_event_unref(struct udev_event *event)
{
        if (event == NULL)
                return;
        udev_list_cleanup(&event->run_list);
        free(event->program_result);
        free(event->name);
        dbg(event->udev, "free event %p\n", event);
        free(event);
}

size_t udev_event_apply_format(struct udev_event *event, const char *src, char *dest, size_t size)
{
        struct udev_device *dev = event->dev;
        enum subst_type {
                SUBST_UNKNOWN,
                SUBST_DEVNODE,
                SUBST_ATTR,
                SUBST_ENV,
                SUBST_KERNEL,
                SUBST_KERNEL_NUMBER,
                SUBST_DRIVER,
                SUBST_DEVPATH,
                SUBST_ID,
                SUBST_MAJOR,
                SUBST_MINOR,
                SUBST_RESULT,
                SUBST_PARENT,
                SUBST_NAME,
                SUBST_LINKS,
                SUBST_ROOT,
                SUBST_SYS,
        };
        static const struct subst_map {
                char *name;
                char fmt;
                enum subst_type type;
        } map[] = {
                { .name = "devnode",        .fmt = 'N',        .type = SUBST_DEVNODE },
                { .name = "tempnode",        .fmt = 'N',        .type = SUBST_DEVNODE },
                { .name = "attr",        .fmt = 's',        .type = SUBST_ATTR },
                { .name = "sysfs",        .fmt = 's',        .type = SUBST_ATTR },
                { .name = "env",        .fmt = 'E',        .type = SUBST_ENV },
                { .name = "kernel",        .fmt = 'k',        .type = SUBST_KERNEL },
                { .name = "number",        .fmt = 'n',        .type = SUBST_KERNEL_NUMBER },
                { .name = "driver",        .fmt = 'd',        .type = SUBST_DRIVER },
                { .name = "devpath",        .fmt = 'p',        .type = SUBST_DEVPATH },
                { .name = "id",                .fmt = 'b',        .type = SUBST_ID },
                { .name = "major",        .fmt = 'M',        .type = SUBST_MAJOR },
                { .name = "minor",        .fmt = 'm',        .type = SUBST_MINOR },
                { .name = "result",        .fmt = 'c',        .type = SUBST_RESULT },
                { .name = "parent",        .fmt = 'P',        .type = SUBST_PARENT },
                { .name = "name",        .fmt = 'D',        .type = SUBST_NAME },
                { .name = "links",        .fmt = 'L',        .type = SUBST_LINKS },
                { .name = "root",        .fmt = 'r',        .type = SUBST_ROOT },
                { .name = "sys",        .fmt = 'S',        .type = SUBST_SYS },
        };
        const char *from;
        char *s;
        size_t l;

        from = src;
        s = dest;
        l = size;

        for (;;) {
                enum subst_type type = SUBST_UNKNOWN;
                char attrbuf[UTIL_PATH_SIZE];
                char *attr = NULL;

                while (from[0] != '\0') {
                        if (from[0] == '$') {
                                /* substitute named variable */
                                unsigned int i;

                                if (from[1] == '$') {
                                        from++;
                                        goto copy;
                                }

                                for (i = 0; i < ARRAY_SIZE(map); i++) {
                                        if (strncmp(&from[1], map[i].name, strlen(map[i].name)) == 0) {
                                                type = map[i].type;
                                                from += strlen(map[i].name)+1;
                                                dbg(event->udev, "will substitute format name '%s'\n", map[i].name);
                                                goto subst;
                                        }
                                }
                        } else if (from[0] == '%') {
                                /* substitute format char */
                                unsigned int i;

                                if (from[1] == '%') {
                                        from++;
                                        goto copy;
                                }

                                for (i = 0; i < ARRAY_SIZE(map); i++) {
                                        if (from[1] == map[i].fmt) {
                                                type = map[i].type;
                                                from += 2;
                                                dbg(event->udev, "will substitute format char '%c'\n", map[i].fmt);
                                                goto subst;
                                        }
                                }
                        }
copy:
                        /* copy char */
                        if (l == 0)
                                goto out;
                        s[0] = from[0];
                        from++;
                        s++;
                        l--;
                }

                goto out;
subst:
                /* extract possible $format{attr} */
                if (from[0] == '{') {
                        unsigned int i;

                        from++;
                        for (i = 0; from[i] != '}'; i++) {
                                if (from[i] == '\0') {
                                        err(event->udev, "missing closing brace for format '%s'\n", src);
                                        goto out;
                                }
                        }
                        if (i >= sizeof(attrbuf))
                                goto out;
                        memcpy(attrbuf, from, i);
                        attrbuf[i] = '\0';
                        from += i+1;
                        attr = attrbuf;
                } else {
                        attr = NULL;
                }

                switch (type) {
                case SUBST_DEVPATH:
                        l = util_strpcpy(&s, l, udev_device_get_devpath(dev));
                        dbg(event->udev, "substitute devpath '%s'\n", udev_device_get_devpath(dev));
                        break;
                case SUBST_KERNEL:
                        l = util_strpcpy(&s, l, udev_device_get_sysname(dev));
                        dbg(event->udev, "substitute kernel name '%s'\n", udev_device_get_sysname(dev));
                        break;
                case SUBST_KERNEL_NUMBER:
                        if (udev_device_get_sysnum(dev) == NULL)
                                break;
                        l = util_strpcpy(&s, l, udev_device_get_sysnum(dev));
                        dbg(event->udev, "substitute kernel number '%s'\n", udev_device_get_sysnum(dev));
                        break;
                case SUBST_ID:
                        if (event->dev_parent == NULL)
                                break;
                        l = util_strpcpy(&s, l, udev_device_get_sysname(event->dev_parent));
                        dbg(event->udev, "substitute id '%s'\n", udev_device_get_sysname(event->dev_parent));
                        break;
                case SUBST_DRIVER: {
                        const char *driver;

                        if (event->dev_parent == NULL)
                                break;

                        driver = udev_device_get_driver(event->dev_parent);
                        if (driver == NULL)
                                break;
                        l = util_strpcpy(&s, l, driver);
                        dbg(event->udev, "substitute driver '%s'\n", driver);
                        break;
                }
                case SUBST_MAJOR: {
                        char num[UTIL_PATH_SIZE];

                        sprintf(num, "%d", major(udev_device_get_devnum(dev)));
                        l = util_strpcpy(&s, l, num);
                        dbg(event->udev, "substitute major number '%s'\n", num);
                        break;
                }
                case SUBST_MINOR: {
                        char num[UTIL_PATH_SIZE];

                        sprintf(num, "%d", minor(udev_device_get_devnum(dev)));
                        l = util_strpcpy(&s, l, num);
                        dbg(event->udev, "substitute minor number '%s'\n", num);
                        break;
                }
                case SUBST_RESULT: {
                        char *rest;
                        int i;

                        if (event->program_result == NULL)
                                break;
                        /* get part part of the result string */
                        i = 0;
                        if (attr != NULL)
                                i = strtoul(attr, &rest, 10);
                        if (i > 0) {
                                char result[UTIL_PATH_SIZE];
                                char tmp[UTIL_PATH_SIZE];
                                char *cpos;

                                dbg(event->udev, "request part #%d of result string\n", i);
                                util_strscpy(result, sizeof(result), event->program_result);
                                cpos = result;
                                while (--i) {
                                        while (cpos[0] != '\0' && !isspace(cpos[0]))
                                                cpos++;
                                        while (isspace(cpos[0]))
                                                cpos++;
                                }
                                if (i > 0) {
                                        err(event->udev, "requested part of result string not found\n");
                                        break;
                                }
                                util_strscpy(tmp, sizeof(tmp), cpos);
                                /* %{2+}c copies the whole string from the second part on */
                                if (rest[0] != '+') {
                                        cpos = strchr(tmp, ' ');
                                        if (cpos)
                                                cpos[0] = '\0';
                                }
                                l = util_strpcpy(&s, l, tmp);
                                dbg(event->udev, "substitute part of result string '%s'\n", tmp);
                        } else {
                                l = util_strpcpy(&s, l, event->program_result);
                                dbg(event->udev, "substitute result string '%s'\n", event->program_result);
                        }
                        break;
                }
                case SUBST_ATTR: {
                        const char *value = NULL;
                        char vbuf[UTIL_NAME_SIZE];
                        size_t len;
                        int count;

                        if (attr == NULL) {
                                err(event->udev, "missing file parameter for attr\n");
                                break;
                        }

                        /* try to read the value specified by "[dmi/id]product_name" */
                        if (util_resolve_subsys_kernel(event->udev, attr, vbuf, sizeof(vbuf), 1) == 0)
                                value = vbuf;

                        /* try to read the attribute the device */
                        if (value == NULL)
                                value = udev_device_get_sysattr_value(event->dev, attr);

                        /* try to read the attribute of the parent device, other matches have selected */
                        if (value == NULL && event->dev_parent != NULL && event->dev_parent != event->dev)
                                value = udev_device_get_sysattr_value(event->dev_parent, attr);

                        if (value == NULL)
                                break;

                        /* strip trailing whitespace, and replace unwanted characters */
                        if (value != vbuf)
                                util_strscpy(vbuf, sizeof(vbuf), value);
                        len = strlen(vbuf);
                        while (len > 0 && isspace(vbuf[--len]))
                                vbuf[len] = '\0';
                        count = util_replace_chars(vbuf, UDEV_ALLOWED_CHARS_INPUT);
                        if (count > 0)
                                info(event->udev, "%i character(s) replaced\n" , count);
                        l = util_strpcpy(&s, l, vbuf);
                        dbg(event->udev, "substitute sysfs value '%s'\n", vbuf);
                        break;
                }
                case SUBST_PARENT: {
                        struct udev_device *dev_parent;
                        const char *devnode;

                        dev_parent = udev_device_get_parent(event->dev);
                        if (dev_parent == NULL)
                                break;
                        devnode = udev_device_get_devnode(dev_parent);
                        if (devnode != NULL) {
                                size_t devlen = strlen(udev_get_dev_path(event->udev))+1;

                                l = util_strpcpy(&s, l, &devnode[devlen]);
                                dbg(event->udev, "found parent '%s', got node name '%s'\n",
                                    udev_device_get_syspath(dev_parent), &devnode[devlen]);
                        }
                        break;
                }
                case SUBST_DEVNODE:
                        if (udev_device_get_devnode(dev) != NULL)
                                l = util_strpcpy(&s, l, udev_device_get_devnode(dev));
                        break;
                case SUBST_NAME: {
                        if (event->name != NULL) {
                                l = util_strpcpy(&s, l, event->name);
                                dbg(event->udev, "substitute custom name '%s'\n", event->name);
                        } else {
                                size_t devlen = strlen(udev_get_dev_path(event->udev))+1;

                                l = util_strpcpy(&s, l, &udev_device_get_devnode(dev)[devlen]);
                                dbg(event->udev, "substitute name'%s'\n", &udev_device_get_devnode(dev)[devlen]);
                        }
                        break;
                }
                case SUBST_LINKS: {
                        size_t devlen = strlen(udev_get_dev_path(event->udev))+1;
                        struct udev_list_entry *list_entry;

                        list_entry = udev_device_get_devlinks_list_entry(dev);
                        if (list_entry == NULL)
                                break;
                        l = util_strpcpy(&s, l, &udev_list_entry_get_name(list_entry)[devlen]);
                        udev_list_entry_foreach(list_entry, udev_list_entry_get_next(list_entry))
                                l = util_strpcpyl(&s, l, " ", &udev_list_entry_get_name(list_entry)[devlen], NULL);
                        break;
                }
                case SUBST_ROOT:
                        l = util_strpcpy(&s, l, udev_get_dev_path(event->udev));
                        dbg(event->udev, "substitute udev_root '%s'\n", udev_get_dev_path(event->udev));
                        break;
                case SUBST_SYS:
                        l = util_strpcpy(&s, l, udev_get_sys_path(event->udev));
                        dbg(event->udev, "substitute sys_path '%s'\n", udev_get_sys_path(event->udev));
                        break;
                case SUBST_ENV:
                        if (attr == NULL) {
                                dbg(event->udev, "missing attribute\n");
                                break;
                        } else {
                                const char *value;

                                value = udev_device_get_property_value(event->dev, attr);
                                if (value == NULL)
                                        break;
                                dbg(event->udev, "substitute env '%s=%s'\n", attr, value);
                                l = util_strpcpy(&s, l, value);
                                break;
                        }
                default:
                        err(event->udev, "unknown substitution type=%i\n", type);
                        break;
                }
        }

out:
        s[0] = '\0';
        dbg(event->udev, "'%s' -> '%s' (%zu)\n", src, dest, l);
        return l;
}

static int spawn_exec(struct udev_event *event,
                      const char *cmd, char *const argv[], char **envp, const sigset_t *sigmask,
                      int fd_stdout, int fd_stderr)
{
        struct udev *udev = event->udev;
        int err;
        int fd;

        /* discard child output or connect to pipe */
        fd = open("/dev/null", O_RDWR);
        if (fd >= 0) {
                dup2(fd, STDIN_FILENO);
                if (fd_stdout < 0)
                        dup2(fd, STDOUT_FILENO);
                if (fd_stderr < 0)
                        dup2(fd, STDERR_FILENO);
                close(fd);
        } else {
                err(udev, "open /dev/null failed: %m\n");
        }

        /* connect pipes to std{out,err} */
        if (fd_stdout >= 0) {
                dup2(fd_stdout, STDOUT_FILENO);
                        close(fd_stdout);
        }
        if (fd_stderr >= 0) {
                dup2(fd_stderr, STDERR_FILENO);
                close(fd_stderr);
        }

        /* terminate child in case parent goes away */
        prctl(PR_SET_PDEATHSIG, SIGTERM);

        /* restore original udev sigmask before exec */
        if (sigmask)
                sigprocmask(SIG_SETMASK, sigmask, NULL);

        execve(argv[0], argv, envp);

        /* exec failed */
        err = -errno;
        err(udev, "failed to execute '%s' '%s': %m\n", argv[0], cmd);
        return err;
}

static void spawn_read(struct udev_event *event,
                      const char *cmd,
                      int fd_stdout, int fd_stderr,
                      char *result, size_t ressize)
{
        struct udev *udev = event->udev;
        size_t respos = 0;
        int fd_ep = -1;
        struct epoll_event ep_outpipe, ep_errpipe;

        /* read from child if requested */
        if (fd_stdout < 0 && fd_stderr < 0)
                return;

        fd_ep = epoll_create1(EPOLL_CLOEXEC);
        if (fd_ep < 0) {
                err(udev, "error creating epoll fd: %m\n");
                goto out;
        }

        if (fd_stdout >= 0) {
                memset(&ep_outpipe, 0, sizeof(struct epoll_event));
                ep_outpipe.events = EPOLLIN;
                ep_outpipe.data.ptr = &fd_stdout;
                if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stdout, &ep_outpipe) < 0) {
                        err(udev, "fail to add fd to epoll: %m\n");
                        goto out;
                }
        }

        if (fd_stderr >= 0) {
                memset(&ep_errpipe, 0, sizeof(struct epoll_event));
                ep_errpipe.events = EPOLLIN;
                ep_errpipe.data.ptr = &fd_stderr;
                if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stderr, &ep_errpipe) < 0) {
                        err(udev, "fail to add fd to epoll: %m\n");
                        goto out;
                }
        }

        /* read child output */
        while (fd_stdout >= 0 || fd_stderr >= 0) {
                int timeout;
                int fdcount;
                struct epoll_event ev[4];
                int i;

                if (event->timeout_usec > 0) {
                        unsigned long long age_usec;

                        age_usec = now_usec() - event->birth_usec;
                        if (age_usec >= event->timeout_usec) {
                                err(udev, "timeout '%s'\n", cmd);
                                goto out;
                        }
                        timeout = ((event->timeout_usec - age_usec) / 1000) + 1000;
                } else {
                        timeout = -1;
                }

                fdcount = epoll_wait(fd_ep, ev, ARRAY_SIZE(ev), timeout);
                if (fdcount < 0) {
                        if (errno == EINTR)
                                continue;
                        err(udev, "failed to poll: %m\n");
                        goto out;
                }
                if (fdcount == 0) {
                        err(udev, "timeout '%s'\n", cmd);
                        goto out;
                }

                for (i = 0; i < fdcount; i++) {
                        int *fd = (int *)ev[i].data.ptr;

                        if (ev[i].events & EPOLLIN) {
                                ssize_t count;
                                char buf[4096];

                                count = read(*fd, buf, sizeof(buf)-1);
                                if (count <= 0)
                                        continue;
                                buf[count] = '\0';

                                /* store stdout result */
                                if (result != NULL && *fd == fd_stdout) {
                                        if (respos + count < ressize) {
                                                memcpy(&result[respos], buf, count);
                                                respos += count;
                                        } else {
                                                err(udev, "'%s' ressize %zd too short\n", cmd, ressize);
                                        }
                                }

                                /* log debug output only if we watch stderr */
                                if (fd_stderr >= 0) {
                                        char *pos;
                                        char *line;

                                        pos = buf;
                                        while ((line = strsep(&pos, "\n"))) {
                                                if (pos != NULL || line[0] != '\0')
                                                        info(udev, "'%s'(%s) '%s'\n", cmd, *fd == fd_stdout ? "out" : "err" , line);
                                        }
                                }
                        } else if (ev[i].events & EPOLLHUP) {
                                if (epoll_ctl(fd_ep, EPOLL_CTL_DEL, *fd, NULL) < 0) {
                                        err(udev, "failed to remove fd from epoll: %m\n");
                                        goto out;
                                }
                                *fd = -1;
                        }
                }
        }

        /* return the child's stdout string */
        if (result != NULL) {
                result[respos] = '\0';
                dbg(udev, "result='%s'\n", result);
        }
out:
        if (fd_ep >= 0)
                close(fd_ep);
}

static int spawn_wait(struct udev_event *event, const char *cmd, pid_t pid)
{
        struct udev *udev = event->udev;
        struct pollfd pfd[1];
        int err = 0;

        pfd[0].events = POLLIN;
        pfd[0].fd = event->fd_signal;

        while (pid > 0) {
                int timeout;
                int fdcount;

                if (event->timeout_usec > 0) {
                        unsigned long long age_usec;

                        age_usec = now_usec() - event->birth_usec;
                        if (age_usec >= event->timeout_usec)
                                timeout = 1000;
                        else
                                timeout = ((event->timeout_usec - age_usec) / 1000) + 1000;
                } else {
                        timeout = -1;
                }

                fdcount = poll(pfd, 1, timeout);
                if (fdcount < 0) {
                        if (errno == EINTR)
                                continue;
                        err = -errno;
                        err(udev, "failed to poll: %m\n");
                        goto out;
                }
                if (fdcount == 0) {
                        err(udev, "timeout: killing '%s' [%u]\n", cmd, pid);
                        kill(pid, SIGKILL);
                }

                if (pfd[0].revents & POLLIN) {
                        struct signalfd_siginfo fdsi;
                        int status;
                        ssize_t size;

                        size = read(event->fd_signal, &fdsi, sizeof(struct signalfd_siginfo));
                        if (size != sizeof(struct signalfd_siginfo))
                                continue;

                        switch (fdsi.ssi_signo) {
                        case SIGTERM:
                                event->sigterm = true;
                                break;
                        case SIGCHLD:
                                if (waitpid(pid, &status, WNOHANG) < 0)
                                        break;
                                if (WIFEXITED(status)) {
                                        info(udev, "'%s' [%u] exit with return code %i\n", cmd, pid, WEXITSTATUS(status));
                                        if (WEXITSTATUS(status) != 0)
                                                err = -1;
                                } else if (WIFSIGNALED(status)) {
                                        err(udev, "'%s' [%u] terminated by signal %i (%s)\n", cmd, pid, WTERMSIG(status), strsignal(WTERMSIG(status)));
                                        err = -1;
                                } else if (WIFSTOPPED(status)) {
                                        err(udev, "'%s' [%u] stopped\n", cmd, pid);
                                        err = -1;
                                } else if (WIFCONTINUED(status)) {
                                        err(udev, "'%s' [%u] continued\n", cmd, pid);
                                        err = -1;
                                } else {
                                        err(udev, "'%s' [%u] exit with status 0x%04x\n", cmd, pid, status);
                                        err = -1;
                                }
                                pid = 0;
                                break;
                        }
                }
        }
out:
        return err;
}

int udev_build_argv(struct udev *udev, char *cmd, int *argc, char *argv[])
{
        int i = 0;
        char *pos;

        if (strchr(cmd, ' ') == NULL) {
                argv[i++] = cmd;
                goto out;
        }

        pos = cmd;
        while (pos != NULL && pos[0] != '\0') {
                if (pos[0] == '\'') {
                        /* do not separate quotes */
                        pos++;
                        argv[i] = strsep(&pos, "\'");
                        if (pos != NULL)
                                while (pos[0] == ' ')
                                        pos++;
                } else {
                        argv[i] = strsep(&pos, " ");
                        if (pos != NULL)
                                while (pos[0] == ' ')
                                        pos++;
                }
                dbg(udev, "argv[%i] '%s'\n", i, argv[i]);
                i++;
        }
out:
        argv[i] = NULL;
        if (argc)
                *argc = i;
        return 0;
}

int udev_event_spawn(struct udev_event *event,
                     const char *cmd, char **envp, const sigset_t *sigmask,
                     char *result, size_t ressize)
{
        struct udev *udev = event->udev;
        int outpipe[2] = {-1, -1};
        int errpipe[2] = {-1, -1};
        pid_t pid;
        char arg[UTIL_PATH_SIZE];
        char *argv[128];
        char program[UTIL_PATH_SIZE];
        int err = 0;

        util_strscpy(arg, sizeof(arg), cmd);
        udev_build_argv(event->udev, arg, NULL, argv);

        /* pipes from child to parent */
        if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
                if (pipe2(outpipe, O_NONBLOCK) != 0) {
                        err = -errno;
                        err(udev, "pipe failed: %m\n");
                        goto out;
                }
        }
        if (udev_get_log_priority(udev) >= LOG_INFO) {
                if (pipe2(errpipe, O_NONBLOCK) != 0) {
                        err = -errno;
                        err(udev, "pipe failed: %m\n");
                        goto out;
                }
        }

        /* allow programs in /usr/lib/udev/ to be called without the path */
        if (argv[0][0] != '/') {
                util_strscpyl(program, sizeof(program), PKGLIBEXECDIR "/", argv[0], NULL);
                argv[0] = program;
        }

        pid = fork();
        switch(pid) {
        case 0:
                /* child closes parent's ends of pipes */
                if (outpipe[READ_END] >= 0) {
                        close(outpipe[READ_END]);
                        outpipe[READ_END] = -1;
                }
                if (errpipe[READ_END] >= 0) {
                        close(errpipe[READ_END]);
                        errpipe[READ_END] = -1;
                }

                info(udev, "starting '%s'\n", cmd);

                err = spawn_exec(event, cmd, argv, envp, sigmask,
                                 outpipe[WRITE_END], errpipe[WRITE_END]);

                _exit(2 );
        case -1:
                err(udev, "fork of '%s' failed: %m\n", cmd);
                err = -1;
                goto out;
        default:
                /* parent closed child's ends of pipes */
                if (outpipe[WRITE_END] >= 0) {
                        close(outpipe[WRITE_END]);
                        outpipe[WRITE_END] = -1;
                }
                if (errpipe[WRITE_END] >= 0) {
                        close(errpipe[WRITE_END]);
                        errpipe[WRITE_END] = -1;
                }

                spawn_read(event, cmd,
                         outpipe[READ_END], errpipe[READ_END],
                         result, ressize);

                err = spawn_wait(event, cmd, pid);
        }

out:
        if (outpipe[READ_END] >= 0)
                close(outpipe[READ_END]);
        if (outpipe[WRITE_END] >= 0)
                close(outpipe[WRITE_END]);
        if (errpipe[READ_END] >= 0)
                close(errpipe[READ_END]);
        if (errpipe[WRITE_END] >= 0)
                close(errpipe[WRITE_END]);
        return err;
}

static void rename_netif_kernel_log(struct ifreq ifr)
{
        int klog;
        FILE *f;

        klog = open("/dev/kmsg", O_WRONLY);
        if (klog < 0)
                return;

        f = fdopen(klog, "w");
        if (f == NULL) {
                close(klog);
                return;
        }

        fprintf(f, "<30>udevd[%u]: renamed network interface %s to %s\n",
                getpid(), ifr.ifr_name, ifr.ifr_newname);
        fclose(f);
}

static int rename_netif(struct udev_event *event)
{
        struct udev_device *dev = event->dev;
        int sk;
        struct ifreq ifr;
        int loop;
        int err;

        info(event->udev, "changing net interface name from '%s' to '%s'\n",
             udev_device_get_sysname(dev), event->name);

        sk = socket(PF_INET, SOCK_DGRAM, 0);
        if (sk < 0) {
                err = -errno;
                err(event->udev, "error opening socket: %m\n");
                return err;
        }

        memset(&ifr, 0x00, sizeof(struct ifreq));
        util_strscpy(ifr.ifr_name, IFNAMSIZ, udev_device_get_sysname(dev));
        util_strscpy(ifr.ifr_newname, IFNAMSIZ, event->name);
        err = ioctl(sk, SIOCSIFNAME, &ifr);
        if (err == 0) {
                rename_netif_kernel_log(ifr);
                goto out;
        }

        /* keep trying if the destination interface name already exists */
        err = -errno;
        if (err != -EEXIST)
                goto out;

        /* free our own name, another process may wait for us */
        snprintf(ifr.ifr_newname, IFNAMSIZ, "rename%u", udev_device_get_ifindex(dev));
        err = ioctl(sk, SIOCSIFNAME, &ifr);
        if (err < 0) {
                err = -errno;
                goto out;
        }

        /* log temporary name */
        rename_netif_kernel_log(ifr);

        /* wait a maximum of 90 seconds for our target to become available */
        util_strscpy(ifr.ifr_name, IFNAMSIZ, ifr.ifr_newname);
        util_strscpy(ifr.ifr_newname, IFNAMSIZ, event->name);
        loop = 90 * 20;
        while (loop--) {
                const struct timespec duration = { 0, 1000 * 1000 * 1000 / 20 };

                dbg(event->udev, "wait for netif '%s' to become free, loop=%i\n",
                    event->name, (90 * 20) - loop);
                nanosleep(&duration, NULL);

                err = ioctl(sk, SIOCSIFNAME, &ifr);
                if (err == 0) {
                        rename_netif_kernel_log(ifr);
                        break;
                }
                err = -errno;
                if (err != -EEXIST)
                        break;
        }

out:
        if (err < 0)
                err(event->udev, "error changing net interface name %s to %s: %m\n", ifr.ifr_name, ifr.ifr_newname);
        close(sk);
        return err;
}

int udev_event_execute_rules(struct udev_event *event, struct udev_rules *rules, const sigset_t *sigmask)
{
        struct udev_device *dev = event->dev;
        int err = 0;

        if (udev_device_get_subsystem(dev) == NULL)
                return -1;

        if (strcmp(udev_device_get_action(dev), "remove") == 0) {
                udev_device_read_db(dev, NULL);
                udev_device_delete_db(dev);
                udev_device_tag_index(dev, NULL, false);

                if (major(udev_device_get_devnum(dev)) != 0)
                        udev_watch_end(event->udev, dev);

                udev_rules_apply_to_event(rules, event, sigmask);

                if (major(udev_device_get_devnum(dev)) != 0)
                        err = udev_node_remove(dev);
        } else {
                event->dev_db = udev_device_new_from_syspath(event->udev, udev_device_get_syspath(dev));
                if (event->dev_db != NULL) {
                        udev_device_read_db(event->dev_db, NULL);
                        udev_device_set_info_loaded(event->dev_db);

                        /* disable watch during event processing */
                        if (major(udev_device_get_devnum(dev)) != 0)
                                udev_watch_end(event->udev, event->dev_db);
                }

                udev_rules_apply_to_event(rules, event, sigmask);

                /* rename a new network interface, if needed */
                if (udev_device_get_ifindex(dev) > 0 && strcmp(udev_device_get_action(dev), "add") == 0 &&
                    event->name != NULL && strcmp(event->name, udev_device_get_sysname(dev)) != 0) {
                        char syspath[UTIL_PATH_SIZE];
                        char *pos;

                        err = rename_netif(event);
                        if (err == 0) {
                                info(event->udev, "renamed netif to '%s'\n", event->name);

                                /* remember old name */
                                udev_device_add_property(dev, "INTERFACE_OLD", udev_device_get_sysname(dev));

                                /* now change the devpath, because the kernel device name has changed */
                                util_strscpy(syspath, sizeof(syspath), udev_device_get_syspath(dev));
                                pos = strrchr(syspath, '/');
                                if (pos != NULL) {
                                        pos++;
                                        util_strscpy(pos, sizeof(syspath) - (pos - syspath), event->name);
                                        udev_device_set_syspath(event->dev, syspath);
                                        udev_device_add_property(dev, "INTERFACE", udev_device_get_sysname(dev));
                                        info(event->udev, "changed devpath to '%s'\n", udev_device_get_devpath(dev));
                                }
                        }
                }

                if (major(udev_device_get_devnum(dev)) > 0) {
                        /* remove/update possible left-over symlinks from old database entry */
                        if (event->dev_db != NULL)
                                udev_node_update_old_links(dev, event->dev_db);

                        if (!event->mode_set) {
                                if (udev_device_get_devnode_mode(dev) > 0) {
                                        /* kernel supplied value */
                                        event->mode = udev_device_get_devnode_mode(dev);
                                } else if (event->gid > 0) {
                                        /* default 0660 if a group is assigned */
                                        event->mode = 0660;
                                } else {
                                        /* default 0600 */
                                        event->mode = 0600;
                                }
                        }

                        err = udev_node_add(dev, event->mode, event->uid, event->gid);
                }

                /* preserve old, or get new initialization timestamp */
                if (event->dev_db != NULL && udev_device_get_usec_initialized(event->dev_db) > 0)
                        udev_device_set_usec_initialized(event->dev, udev_device_get_usec_initialized(event->dev_db));
                else if (udev_device_get_usec_initialized(event->dev) == 0)
                        udev_device_set_usec_initialized(event->dev, now_usec());

                /* (re)write database file */
                udev_device_update_db(dev);
                udev_device_tag_index(dev, event->dev_db, true);
                udev_device_set_is_initialized(dev);

                udev_device_unref(event->dev_db);
                event->dev_db = NULL;
        }
out:
        return err;
}

int udev_event_execute_run(struct udev_event *event, const sigset_t *sigmask)
{
        struct udev_list_entry *list_entry;
        int err = 0;

        dbg(event->udev, "executing run list\n");
        udev_list_entry_foreach(list_entry, udev_list_get_entry(&event->run_list)) {
                const char *cmd = udev_list_entry_get_name(list_entry);

                if (strncmp(cmd, "socket:", strlen("socket:")) == 0) {
                        struct udev_monitor *monitor;

                        monitor = udev_monitor_new_from_socket(event->udev, &cmd[strlen("socket:")]);
                        if (monitor == NULL)
                                continue;
                        udev_monitor_send_device(monitor, NULL, event->dev);
                        udev_monitor_unref(monitor);
                } else {
                        char program[UTIL_PATH_SIZE];
                        char **envp;

                        if (event->exec_delay > 0) {
                                info(event->udev, "delay execution of '%s'\n", program);
                                sleep(event->exec_delay);
                        }

                        udev_event_apply_format(event, cmd, program, sizeof(program));
                        envp = udev_device_get_properties_envp(event->dev);
                        if (udev_event_spawn(event, program, envp, sigmask, NULL, 0) < 0) {
                                if (udev_list_entry_get_num(list_entry))
                                        err = -1;
                        }
                }
        }
        return err;
}