initd/preinit.c

   1 /*
   2  * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
   3  * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU Lesser General Public License version 2.1
   7  * as published by the Free Software Foundation
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14 #define _GNU_SOURCE
  15
  16 #include <sys/stat.h>
  17 #include <sys/types.h>
  18 #include <sys/mount.h>
  19 #include <fcntl.h>
  20
  21 #include <libubox/uloop.h>
  22 #include <libubox/utils.h>
  23 #include <libubus.h>
  24
  25 #include <stdio.h>
  26
  27 #include <unistd.h>
  28
  29 #include "init.h"
  30 #include "../watchdog.h"
  31 #include "../sysupgrade.h"
  32
  33 static struct uloop_process preinit_proc;
  34 static struct uloop_process plugd_proc;
  35
  36 static void
  37 check_dbglvl(void)
  38 {
  39         FILE *fp = fopen("/tmp/debug_level", "r");
  40         int lvl = 0;
  41
  42         if (!fp)
  43                 return;
  44         if (fscanf(fp, "%d", &lvl) == EOF)
  45                 ERROR("failed to read debug level: %m\n");
  46         fclose(fp);
  47         unlink("/tmp/debug_level");
  48
  49         if (lvl > 0 && lvl < 5)
  50                 debug = lvl;
  51 }
  52
  53 static void
  54 check_sysupgrade(void)
  55 {
  56         char *prefix = NULL, *path = NULL, *command = NULL;
  57         size_t n;
  58
  59         if (chdir("/"))
  60                 return;
  61
  62         FILE *sysupgrade = fopen("/tmp/sysupgrade", "r");
  63         if (!sysupgrade)
  64                 return;
  65
  66         n = 0;
  67         if (getdelim(&prefix, &n, 0, sysupgrade) < 0)
  68                 goto fail;
  69         n = 0;
  70         if (getdelim(&path, &n, 0, sysupgrade) < 0)
  71                 goto fail;
  72         n = 0;
  73         if (getdelim(&command, &n, 0, sysupgrade) < 0)
  74                 goto fail;
  75
  76         fclose(sysupgrade);
  77
  78         sysupgrade_exec_upgraded(prefix, path, command);
  79
  80         while (true)
  81                 sleep(1);
  82
  83 fail:
  84         fclose(sysupgrade);
  85         free(prefix);
  86         free(path);
  87         free(command);
  88 }
  89
  90 static void
  91 spawn_procd(struct uloop_process *proc, int ret)
  92 {
  93         char *wdt_fd = watchdog_fd();
  94         char *argv[] = { "/sbin/procd", NULL};
  95         char dbg[2];
  96
  97         if (plugd_proc.pid > 0)
  98                 kill(plugd_proc.pid, SIGKILL);
  99
 100         unsetenv("INITRAMFS");
 101         unsetenv("PREINIT");
 102         unlink("/tmp/.preinit");
 103
 104         check_sysupgrade();
 105
 106         DEBUG(2, "Exec to real procd now\n");
 107         if (wdt_fd)
 108                 setenv("WDTFD", wdt_fd, 1);
 109         check_dbglvl();
 110         if (debug > 0) {
 111                 snprintf(dbg, 2, "%d", debug);
 112                 setenv("DBGLVL", dbg, 1);
 113         }
 114
 115         execvp(argv[0], argv);
 116 }
 117
 118 static void
 119 plugd_proc_cb(struct uloop_process *proc, int ret)
 120 {
 121         proc->pid = 0;
 122 }
 123
 124 void
 125 preinit(void)
 126 {
 127         char *init[] = { "/bin/sh", "/etc/preinit", NULL };
 128         char *plug[] = { "/sbin/procd", "-h", "/etc/hotplug-preinit.json", NULL };
 129         int fd;
 130
 131         LOG("- preinit -\n");
 132
 133         plugd_proc.cb = plugd_proc_cb;
 134         plugd_proc.pid = fork();
 135         if (!plugd_proc.pid) {
 136                 execvp(plug[0], plug);
 137                 ERROR("Failed to start plugd: %m\n");
 138                 exit(-1);
 139         }
 140         if (plugd_proc.pid <= 0) {
 141                 ERROR("Failed to start new plugd instance: %m\n");
 142                 return;
 143         }
 144         uloop_process_add(&plugd_proc);
 145
 146         setenv("PREINIT", "1", 1);
 147
 148         fd = creat("/tmp/.preinit", 0600);
 149
 150         if (fd < 0)
 151                 ERROR("Failed to create sentinel file: %m\n");
 152         else
 153                 close(fd);
 154
 155         preinit_proc.cb = spawn_procd;
 156         preinit_proc.pid = fork();
 157         if (!preinit_proc.pid) {
 158                 execvp(init[0], init);
 159                 ERROR("Failed to start preinit: %m\n");
 160                 exit(-1);
 161         }
 162         if (preinit_proc.pid <= 0) {
 163                 ERROR("Failed to start new preinit instance: %m\n");
 164                 return;
 165         }
 166         uloop_process_add(&preinit_proc);
 167
 168         DEBUG(4, "Launched preinit instance, pid=%d\n", (int) preinit_proc.pid);
 169 }