init.c revision 2268718ee2b23936f6db88eff7af03762713c169 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdio.h>
18#include <stdlib.h>
19#include <string.h>
20#include <unistd.h>
21#include <fcntl.h>
22#include <ctype.h>
23#include <signal.h>
24#include <sys/wait.h>
25#include <sys/mount.h>
26#include <sys/stat.h>
27#include <sys/poll.h>
28#include <errno.h>
29#include <stdarg.h>
30#include <mtd/mtd-user.h>
31#include <sys/types.h>
32#include <sys/socket.h>
33#include <sys/un.h>
34#include <libgen.h>
35
36#include <cutils/sockets.h>
37#include <cutils/iosched_policy.h>
38#include <private/android_filesystem_config.h>
39#include <termios.h>
40
41#include <sys/system_properties.h>
42
43#include "devices.h"
44#include "init.h"
45#include "list.h"
46#include "log.h"
47#include "property_service.h"
48#include "bootchart.h"
49#include "signal_handler.h"
50#include "keychords.h"
51#include "init_parser.h"
52#include "util.h"
53#include "ueventd.h"
54
55static int property_triggers_enabled = 0;
56
57#if BOOTCHART
58static int   bootchart_count;
59#endif
60
61static char console[32];
62static char serialno[32];
63static char bootmode[32];
64static char baseband[32];
65static char carrier[32];
66static char bootloader[32];
67static char hardware[32];
68static unsigned revision = 0;
69static char qemu[32];
70
71static struct action *cur_action = NULL;
72static struct command *cur_command = NULL;
73static struct listnode *command_queue = NULL;
74
75void notify_service_state(const char *name, const char *state)
76{
77    char pname[PROP_NAME_MAX];
78    int len = strlen(name);
79    if ((len + 10) > PROP_NAME_MAX)
80        return;
81    snprintf(pname, sizeof(pname), "init.svc.%s", name);
82    property_set(pname, state);
83}
84
85static int have_console;
86static char *console_name = "/dev/console";
87static time_t process_needs_restart;
88
89static const char *ENV[32];
90
91/* add_environment - add "key=value" to the current environment */
92int add_environment(const char *key, const char *val)
93{
94    int n;
95
96    for (n = 0; n < 31; n++) {
97        if (!ENV[n]) {
98            size_t len = strlen(key) + strlen(val) + 2;
99            char *entry = malloc(len);
100            snprintf(entry, len, "%s=%s", key, val);
101            ENV[n] = entry;
102            return 0;
103        }
104    }
105
106    return 1;
107}
108
109static void zap_stdio(void)
110{
111    int fd;
112    fd = open("/dev/null", O_RDWR);
113    dup2(fd, 0);
114    dup2(fd, 1);
115    dup2(fd, 2);
116    close(fd);
117}
118
119static void open_console()
120{
121    int fd;
122    if ((fd = open(console_name, O_RDWR)) < 0) {
123        fd = open("/dev/null", O_RDWR);
124    }
125    dup2(fd, 0);
126    dup2(fd, 1);
127    dup2(fd, 2);
128    close(fd);
129}
130
131static void publish_socket(const char *name, int fd)
132{
133    char key[64] = ANDROID_SOCKET_ENV_PREFIX;
134    char val[64];
135
136    strlcpy(key + sizeof(ANDROID_SOCKET_ENV_PREFIX) - 1,
137            name,
138            sizeof(key) - sizeof(ANDROID_SOCKET_ENV_PREFIX));
139    snprintf(val, sizeof(val), "%d", fd);
140    add_environment(key, val);
141
142    /* make sure we don't close-on-exec */
143    fcntl(fd, F_SETFD, 0);
144}
145
146void service_start(struct service *svc, const char *dynamic_args)
147{
148    struct stat s;
149    pid_t pid;
150    int needs_console;
151    int n;
152
153        /* starting a service removes it from the disabled
154         * state and immediately takes it out of the restarting
155         * state if it was in there
156         */
157    svc->flags &= (~(SVC_DISABLED|SVC_RESTARTING));
158    svc->time_started = 0;
159
160        /* running processes require no additional work -- if
161         * they're in the process of exiting, we've ensured
162         * that they will immediately restart on exit, unless
163         * they are ONESHOT
164         */
165    if (svc->flags & SVC_RUNNING) {
166        return;
167    }
168
169    needs_console = (svc->flags & SVC_CONSOLE) ? 1 : 0;
170    if (needs_console && (!have_console)) {
171        ERROR("service '%s' requires console\n", svc->name);
172        svc->flags |= SVC_DISABLED;
173        return;
174    }
175
176    if (stat(svc->args[0], &s) != 0) {
177        ERROR("cannot find '%s', disabling '%s'\n", svc->args[0], svc->name);
178        svc->flags |= SVC_DISABLED;
179        return;
180    }
181
182    if ((!(svc->flags & SVC_ONESHOT)) && dynamic_args) {
183        ERROR("service '%s' must be one-shot to use dynamic args, disabling\n",
184               svc->args[0]);
185        svc->flags |= SVC_DISABLED;
186        return;
187    }
188
189    NOTICE("starting '%s'\n", svc->name);
190
191    pid = fork();
192
193    if (pid == 0) {
194        struct socketinfo *si;
195        struct svcenvinfo *ei;
196        char tmp[32];
197        int fd, sz;
198
199        if (properties_inited()) {
200            get_property_workspace(&fd, &sz);
201            sprintf(tmp, "%d,%d", dup(fd), sz);
202            add_environment("ANDROID_PROPERTY_WORKSPACE", tmp);
203        }
204
205        for (ei = svc->envvars; ei; ei = ei->next)
206            add_environment(ei->name, ei->value);
207
208        for (si = svc->sockets; si; si = si->next) {
209            int socket_type = (
210                    !strcmp(si->type, "stream") ? SOCK_STREAM :
211                        (!strcmp(si->type, "dgram") ? SOCK_DGRAM : SOCK_SEQPACKET));
212            int s = create_socket(si->name, socket_type,
213                                  si->perm, si->uid, si->gid);
214            if (s >= 0) {
215                publish_socket(si->name, s);
216            }
217        }
218
219        if (svc->ioprio_class != IoSchedClass_NONE) {
220            if (android_set_ioprio(getpid(), svc->ioprio_class, svc->ioprio_pri)) {
221                ERROR("Failed to set pid %d ioprio = %d,%d: %s\n",
222                      getpid(), svc->ioprio_class, svc->ioprio_pri, strerror(errno));
223            }
224        }
225
226        if (needs_console) {
227            setsid();
228            open_console();
229        } else {
230            zap_stdio();
231        }
232
233#if 0
234        for (n = 0; svc->args[n]; n++) {
235            INFO("args[%d] = '%s'\n", n, svc->args[n]);
236        }
237        for (n = 0; ENV[n]; n++) {
238            INFO("env[%d] = '%s'\n", n, ENV[n]);
239        }
240#endif
241
242        setpgid(0, getpid());
243
244    /* as requested, set our gid, supplemental gids, and uid */
245        if (svc->gid) {
246            if (setgid(svc->gid) != 0) {
247                ERROR("setgid failed: %s\n", strerror(errno));
248                _exit(127);
249            }
250        }
251        if (svc->nr_supp_gids) {
252            if (setgroups(svc->nr_supp_gids, svc->supp_gids) != 0) {
253                ERROR("setgroups failed: %s\n", strerror(errno));
254                _exit(127);
255            }
256        }
257        if (svc->uid) {
258            if (setuid(svc->uid) != 0) {
259                ERROR("setuid failed: %s\n", strerror(errno));
260                _exit(127);
261            }
262        }
263
264        if (!dynamic_args) {
265            if (execve(svc->args[0], (char**) svc->args, (char**) ENV) < 0) {
266                ERROR("cannot execve('%s'): %s\n", svc->args[0], strerror(errno));
267            }
268        } else {
269            char *arg_ptrs[INIT_PARSER_MAXARGS+1];
270            int arg_idx = svc->nargs;
271            char *tmp = strdup(dynamic_args);
272            char *next = tmp;
273            char *bword;
274
275            /* Copy the static arguments */
276            memcpy(arg_ptrs, svc->args, (svc->nargs * sizeof(char *)));
277
278            while((bword = strsep(&next, " "))) {
279                arg_ptrs[arg_idx++] = bword;
280                if (arg_idx == INIT_PARSER_MAXARGS)
281                    break;
282            }
283            arg_ptrs[arg_idx] = '\0';
284            execve(svc->args[0], (char**) arg_ptrs, (char**) ENV);
285        }
286        _exit(127);
287    }
288
289    if (pid < 0) {
290        ERROR("failed to start '%s'\n", svc->name);
291        svc->pid = 0;
292        return;
293    }
294
295    svc->time_started = gettime();
296    svc->pid = pid;
297    svc->flags |= SVC_RUNNING;
298
299    if (properties_inited())
300        notify_service_state(svc->name, "running");
301}
302
303void service_stop(struct service *svc)
304{
305        /* we are no longer running, nor should we
306         * attempt to restart
307         */
308    svc->flags &= (~(SVC_RUNNING|SVC_RESTARTING));
309
310        /* if the service has not yet started, prevent
311         * it from auto-starting with its class
312         */
313    svc->flags |= SVC_DISABLED;
314
315    if (svc->pid) {
316        NOTICE("service '%s' is being killed\n", svc->name);
317        kill(-svc->pid, SIGTERM);
318        notify_service_state(svc->name, "stopping");
319    } else {
320        notify_service_state(svc->name, "stopped");
321    }
322}
323
324void property_changed(const char *name, const char *value)
325{
326    if (property_triggers_enabled)
327        queue_property_triggers(name, value);
328}
329
330static void restart_service_if_needed(struct service *svc)
331{
332    time_t next_start_time = svc->time_started + 5;
333
334    if (next_start_time <= gettime()) {
335        svc->flags &= (~SVC_RESTARTING);
336        service_start(svc, NULL);
337        return;
338    }
339
340    if ((next_start_time < process_needs_restart) ||
341        (process_needs_restart == 0)) {
342        process_needs_restart = next_start_time;
343    }
344}
345
346static void restart_processes()
347{
348    process_needs_restart = 0;
349    service_for_each_flags(SVC_RESTARTING,
350                           restart_service_if_needed);
351}
352
353static void msg_start(const char *name)
354{
355    struct service *svc;
356    char *tmp = NULL;
357    char *args = NULL;
358
359    if (!strchr(name, ':'))
360        svc = service_find_by_name(name);
361    else {
362        tmp = strdup(name);
363        args = strchr(tmp, ':');
364        *args = '\0';
365        args++;
366
367        svc = service_find_by_name(tmp);
368    }
369
370    if (svc) {
371        service_start(svc, args);
372    } else {
373        ERROR("no such service '%s'\n", name);
374    }
375    if (tmp)
376        free(tmp);
377}
378
379static void msg_stop(const char *name)
380{
381    struct service *svc = service_find_by_name(name);
382
383    if (svc) {
384        service_stop(svc);
385    } else {
386        ERROR("no such service '%s'\n", name);
387    }
388}
389
390void handle_control_message(const char *msg, const char *arg)
391{
392    if (!strcmp(msg,"start")) {
393        msg_start(arg);
394    } else if (!strcmp(msg,"stop")) {
395        msg_stop(arg);
396    } else if (!strcmp(msg,"restart")) {
397        msg_stop(arg);
398        msg_start(arg);
399    } else {
400        ERROR("unknown control msg '%s'\n", msg);
401    }
402}
403
404static void import_kernel_nv(char *name, int in_qemu)
405{
406    char *value = strchr(name, '=');
407
408    if (value == 0) return;
409    *value++ = 0;
410    if (*name == 0) return;
411
412    if (!in_qemu)
413    {
414        /* on a real device, white-list the kernel options */
415        if (!strcmp(name,"qemu")) {
416            strlcpy(qemu, value, sizeof(qemu));
417        } else if (!strcmp(name,"androidboot.console")) {
418            strlcpy(console, value, sizeof(console));
419        } else if (!strcmp(name,"androidboot.mode")) {
420            strlcpy(bootmode, value, sizeof(bootmode));
421        } else if (!strcmp(name,"androidboot.serialno")) {
422            strlcpy(serialno, value, sizeof(serialno));
423        } else if (!strcmp(name,"androidboot.baseband")) {
424            strlcpy(baseband, value, sizeof(baseband));
425        } else if (!strcmp(name,"androidboot.carrier")) {
426            strlcpy(carrier, value, sizeof(carrier));
427        } else if (!strcmp(name,"androidboot.bootloader")) {
428            strlcpy(bootloader, value, sizeof(bootloader));
429        } else if (!strcmp(name,"androidboot.hardware")) {
430            strlcpy(hardware, value, sizeof(hardware));
431        }
432    } else {
433        /* in the emulator, export any kernel option with the
434         * ro.kernel. prefix */
435        char  buff[32];
436        int   len = snprintf( buff, sizeof(buff), "ro.kernel.%s", name );
437        if (len < (int)sizeof(buff)) {
438            property_set( buff, value );
439        }
440    }
441}
442
443static void import_kernel_cmdline(int in_qemu)
444{
445    char cmdline[1024];
446    char *ptr;
447    int fd;
448
449    fd = open("/proc/cmdline", O_RDONLY);
450    if (fd >= 0) {
451        int n = read(fd, cmdline, 1023);
452        if (n < 0) n = 0;
453
454        /* get rid of trailing newline, it happens */
455        if (n > 0 && cmdline[n-1] == '\n') n--;
456
457        cmdline[n] = 0;
458        close(fd);
459    } else {
460        cmdline[0] = 0;
461    }
462
463    ptr = cmdline;
464    while (ptr && *ptr) {
465        char *x = strchr(ptr, ' ');
466        if (x != 0) *x++ = 0;
467        import_kernel_nv(ptr, in_qemu);
468        ptr = x;
469    }
470
471        /* don't expose the raw commandline to nonpriv processes */
472    chmod("/proc/cmdline", 0440);
473}
474
475static struct command *get_first_command(struct action *act)
476{
477    struct listnode *node;
478    node = list_head(&act->commands);
479    if (!node)
480        return NULL;
481
482    return node_to_item(node, struct command, clist);
483}
484
485static struct command *get_next_command(struct action *act, struct command *cmd)
486{
487    struct listnode *node;
488    node = cmd->clist.next;
489    if (!node)
490        return NULL;
491    if (node == &act->commands)
492        return NULL;
493
494    return node_to_item(node, struct command, clist);
495}
496
497static int is_last_command(struct action *act, struct command *cmd)
498{
499    return (list_tail(&act->commands) == &cmd->clist);
500}
501
502void execute_one_command(void)
503{
504    int ret;
505
506    if (!cur_action || !cur_command || is_last_command(cur_action, cur_command)) {
507        cur_action = action_remove_queue_head();
508        cur_command = NULL;
509        if (!cur_action)
510            return;
511        INFO("processing action %p (%s)\n", cur_action, cur_action->name);
512        cur_command = get_first_command(cur_action);
513    } else {
514        cur_command = get_next_command(cur_action, cur_command);
515    }
516
517    if (!cur_command)
518        return;
519
520    ret = cur_command->func(cur_command->nargs, cur_command->args);
521    INFO("command '%s' r=%d\n", cur_command->args[0], ret);
522}
523
524static int wait_for_coldboot_done_action(int nargs, char **args)
525{
526    int ret;
527    INFO("wait for %s\n", coldboot_done);
528    ret = wait_for_file(coldboot_done, COMMAND_RETRY_TIMEOUT);
529    if (ret)
530        ERROR("Timed out waiting for %s\n", coldboot_done);
531    return ret;
532}
533
534static int property_init_action(int nargs, char **args)
535{
536    INFO("property init\n");
537    property_init();
538    return 0;
539}
540
541static int keychord_init_action(int nargs, char **args)
542{
543    keychord_init();
544    return 0;
545}
546
547static int console_init_action(int nargs, char **args)
548{
549    int fd;
550    char tmp[PROP_VALUE_MAX];
551
552    if (console[0]) {
553        snprintf(tmp, sizeof(tmp), "/dev/%s", console);
554        console_name = strdup(tmp);
555    }
556
557    fd = open(console_name, O_RDWR);
558    if (fd >= 0)
559        have_console = 1;
560    close(fd);
561
562    if( load_565rle_image(INIT_IMAGE_FILE) ) {
563        fd = open("/dev/tty0", O_WRONLY);
564        if (fd >= 0) {
565            const char *msg;
566                msg = "\n"
567            "\n"
568            "\n"
569            "\n"
570            "\n"
571            "\n"
572            "\n"  // console is 40 cols x 30 lines
573            "\n"
574            "\n"
575            "\n"
576            "\n"
577            "\n"
578            "\n"
579            "\n"
580            "             A N D R O I D ";
581            write(fd, msg, strlen(msg));
582            close(fd);
583        }
584    }
585    return 0;
586}
587
588static int set_init_properties_action(int nargs, char **args)
589{
590    char tmp[PROP_VALUE_MAX];
591
592    if (qemu[0])
593        import_kernel_cmdline(1);
594
595    if (!strcmp(bootmode,"factory"))
596        property_set("ro.factorytest", "1");
597    else if (!strcmp(bootmode,"factory2"))
598        property_set("ro.factorytest", "2");
599    else
600        property_set("ro.factorytest", "0");
601
602    property_set("ro.serialno", serialno[0] ? serialno : "");
603    property_set("ro.bootmode", bootmode[0] ? bootmode : "unknown");
604    property_set("ro.baseband", baseband[0] ? baseband : "unknown");
605    property_set("ro.carrier", carrier[0] ? carrier : "unknown");
606    property_set("ro.bootloader", bootloader[0] ? bootloader : "unknown");
607
608    property_set("ro.hardware", hardware);
609    snprintf(tmp, PROP_VALUE_MAX, "%d", revision);
610    property_set("ro.revision", tmp);
611    return 0;
612}
613
614static int property_service_init_action(int nargs, char **args)
615{
616    /* read any property files on system or data and
617     * fire up the property service.  This must happen
618     * after the ro.foo properties are set above so
619     * that /data/local.prop cannot interfere with them.
620     */
621    start_property_service();
622    return 0;
623}
624
625static int signal_init_action(int nargs, char **args)
626{
627    signal_init();
628    return 0;
629}
630
631static int check_startup_action(int nargs, char **args)
632{
633    /* make sure we actually have all the pieces we need */
634    if ((get_property_set_fd() < 0) ||
635        (get_signal_fd() < 0)) {
636        ERROR("init startup failure\n");
637        exit(1);
638    }
639    return 0;
640}
641
642static int queue_property_triggers_action(int nargs, char **args)
643{
644    queue_all_property_triggers();
645    /* enable property triggers */
646    property_triggers_enabled = 1;
647    return 0;
648}
649
650#if BOOTCHART
651static int bootchart_init_action(int nargs, char **args)
652{
653    bootchart_count = bootchart_init();
654    if (bootchart_count < 0) {
655        ERROR("bootcharting init failure\n");
656    } else if (bootchart_count > 0) {
657        NOTICE("bootcharting started (period=%d ms)\n", bootchart_count*BOOTCHART_POLLING_MS);
658    } else {
659        NOTICE("bootcharting ignored\n");
660    }
661}
662#endif
663
664int main(int argc, char **argv)
665{
666    int fd_count = 0;
667    struct pollfd ufds[4];
668    char *tmpdev;
669    char* debuggable;
670    char tmp[32];
671    int property_set_fd_init = 0;
672    int signal_fd_init = 0;
673    int keychord_fd_init = 0;
674
675    if (!strcmp(basename(argv[0]), "ueventd"))
676        return ueventd_main(argc, argv);
677
678    /* clear the umask */
679    umask(0);
680
681        /* Get the basic filesystem setup we need put
682         * together in the initramdisk on / and then we'll
683         * let the rc file figure out the rest.
684         */
685    mkdir("/dev", 0755);
686    mkdir("/proc", 0755);
687    mkdir("/sys", 0755);
688
689    mount("tmpfs", "/dev", "tmpfs", MS_NOSUID, "mode=0755");
690    mkdir("/dev/pts", 0755);
691    mkdir("/dev/socket", 0755);
692    mount("devpts", "/dev/pts", "devpts", 0, NULL);
693    mount("proc", "/proc", "proc", 0, NULL);
694    mount("sysfs", "/sys", "sysfs", 0, NULL);
695
696        /* We must have some place other than / to create the
697         * device nodes for kmsg and null, otherwise we won't
698         * be able to remount / read-only later on.
699         * Now that tmpfs is mounted on /dev, we can actually
700         * talk to the outside world.
701         */
702    open_devnull_stdio();
703    log_init();
704
705    INFO("reading config file\n");
706    init_parse_config_file("/init.rc");
707
708    /* pull the kernel commandline and ramdisk properties file in */
709    import_kernel_cmdline(0);
710
711    get_hardware_name(hardware, &revision);
712    snprintf(tmp, sizeof(tmp), "/init.%s.rc", hardware);
713    init_parse_config_file(tmp);
714
715    action_for_each_trigger("early-init", action_add_queue_tail);
716
717    queue_builtin_action(wait_for_coldboot_done_action, "wait_for_coldboot_done");
718    queue_builtin_action(property_init_action, "property_init");
719    queue_builtin_action(keychord_init_action, "keychord_init");
720    queue_builtin_action(console_init_action, "console_init");
721    queue_builtin_action(set_init_properties_action, "set_init_properties");
722
723        /* execute all the boot actions to get us started */
724    action_for_each_trigger("init", action_add_queue_tail);
725    action_for_each_trigger("early-fs", action_add_queue_tail);
726    action_for_each_trigger("fs", action_add_queue_tail);
727    action_for_each_trigger("post-fs", action_add_queue_tail);
728
729    queue_builtin_action(property_service_init_action, "property_service_init");
730    queue_builtin_action(signal_init_action, "signal_init");
731    queue_builtin_action(check_startup_action, "check_startup");
732
733    /* execute all the boot actions to get us started */
734    action_for_each_trigger("early-boot", action_add_queue_tail);
735    action_for_each_trigger("boot", action_add_queue_tail);
736
737        /* run all property triggers based on current state of the properties */
738    queue_builtin_action(queue_property_triggers_action, "queue_propety_triggers");
739
740
741#if BOOTCHART
742    queue_builtin_action(bootchart_init_action, "bootchart_init");
743#endif
744
745    for(;;) {
746        int nr, i, timeout = -1;
747
748        execute_one_command();
749        restart_processes();
750
751        if (!property_set_fd_init && get_property_set_fd() > 0) {
752            ufds[fd_count].fd = get_property_set_fd();
753            ufds[fd_count].events = POLLIN;
754            ufds[fd_count].revents = 0;
755            fd_count++;
756            property_set_fd_init = 1;
757        }
758        if (!signal_fd_init && get_signal_fd() > 0) {
759            ufds[fd_count].fd = get_signal_fd();
760            ufds[fd_count].events = POLLIN;
761            ufds[fd_count].revents = 0;
762            fd_count++;
763            signal_fd_init = 1;
764        }
765        if (!keychord_fd_init && get_keychord_fd() > 0) {
766            ufds[fd_count].fd = get_keychord_fd();
767            ufds[fd_count].events = POLLIN;
768            ufds[fd_count].revents = 0;
769            fd_count++;
770            keychord_fd_init = 1;
771        }
772
773        if (process_needs_restart) {
774            timeout = (process_needs_restart - gettime()) * 1000;
775            if (timeout < 0)
776                timeout = 0;
777        }
778
779        if (!action_queue_empty() || cur_action)
780            timeout = 0;
781
782#if BOOTCHART
783        if (bootchart_count > 0) {
784            if (timeout < 0 || timeout > BOOTCHART_POLLING_MS)
785                timeout = BOOTCHART_POLLING_MS;
786            if (bootchart_step() < 0 || --bootchart_count == 0) {
787                bootchart_finish();
788                bootchart_count = 0;
789            }
790        }
791#endif
792
793        nr = poll(ufds, fd_count, timeout);
794        if (nr <= 0)
795            continue;
796
797        for (i = 0; i < fd_count; i++) {
798            if (ufds[i].revents == POLLIN) {
799                if (ufds[i].fd == get_property_set_fd())
800                    handle_property_set_fd();
801                else if (ufds[i].fd == get_keychord_fd())
802                    handle_keychord();
803                else if (ufds[i].fd == get_signal_fd())
804                    handle_signal();
805            }
806        }
807    }
808
809    return 0;
810}
811