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
  15 #include <sys/stat.h>
  16 #include <sys/types.h>
  17 #include <sys/mount.h>
  18 #include <fcntl.h>
  19
  20 #include <libubox/uloop.h>
  21 #include <libubox/utils.h>
  22 #include <libubus.h>
  23
  24 #include <stdio.h>
  25
  26 #include <unistd.h>
  27
  28 #include "init.h"
  29 #include "../watchdog.h"
  30
  31 static struct uloop_process preinit_proc;
  32 static struct uloop_process plugd_proc;
  33
  34 static void
  35 check_dbglvl(void)
  36 {
  37         FILE *fp = fopen("/tmp/debug_level", "r");
  38         int lvl = 0;
  39
  40         if (!fp)
  41                 return;
  42         if (fscanf(fp, "%d", &lvl) == EOF)
  43                 ERROR("failed to read debug level\n");
  44         fclose(fp);
  45         unlink("/tmp/debug_level");
  46
  47         if (lvl > 0 && lvl < 5)
  48                 debug = lvl;
  49 }
  50
  51 static void
  52 spawn_procd(struct uloop_process *proc, int ret)
  53 {
  54         char *wdt_fd = watchdog_fd();
  55         char *argv[] = { "/sbin/procd", NULL};
  56         struct stat s;
  57         char dbg[2];
  58
  59         if (plugd_proc.pid > 0)
  60                 kill(plugd_proc.pid, SIGKILL);
  61
  62         if (!stat("/tmp/sysupgrade", &s))
  63                 while (true)
  64                         sleep(1);
  65
  66         unsetenv("INITRAMFS");
  67         unsetenv("PREINIT");
  68         unlink("/tmp/.preinit");
  69         DEBUG(2, "Exec to real procd now\n");
  70         if (wdt_fd)
  71                 setenv("WDTFD", wdt_fd, 1);
  72         check_dbglvl();
  73         if (debug > 0) {
  74                 snprintf(dbg, 2, "%d", debug);
  75                 setenv("DBGLVL", dbg, 1);
  76         }
  77
  78         execvp(argv[0], argv);
  79 }
  80
  81 static void
  82 plugd_proc_cb(struct uloop_process *proc, int ret)
  83 {
  84         proc->pid = 0;
  85 }
  86
  87 void
  88 preinit(void)
  89 {
  90         char *init[] = { "/bin/sh", "/etc/preinit", NULL };
  91         char *plug[] = { "/sbin/procd", "-h", "/etc/hotplug-preinit.json", NULL };
  92         int fd;
  93
  94         LOG("- preinit -\n");
  95
  96         plugd_proc.cb = plugd_proc_cb;
  97         plugd_proc.pid = fork();
  98         if (!plugd_proc.pid) {
  99                 execvp(plug[0], plug);
 100                 ERROR("Failed to start plugd\n");
 101                 exit(-1);
 102         }
 103         if (plugd_proc.pid <= 0) {
 104                 ERROR("Failed to start new plugd instance\n");
 105                 return;
 106         }
 107         uloop_process_add(&plugd_proc);
 108
 109         setenv("PREINIT", "1", 1);
 110
 111         fd = creat("/tmp/.preinit", 0600);
 112
 113         if (fd < 0)
 114                 ERROR("Failed to create sentinel file\n");
 115         else
 116                 close(fd);
 117
 118         preinit_proc.cb = spawn_procd;
 119         preinit_proc.pid = fork();
 120         if (!preinit_proc.pid) {
 121                 execvp(init[0], init);
 122                 ERROR("Failed to start preinit\n");
 123                 exit(-1);
 124         }
 125         if (preinit_proc.pid <= 0) {
 126                 ERROR("Failed to start new preinit instance\n");
 127                 return;
 128         }
 129         uloop_process_add(&preinit_proc);
 130
 131         DEBUG(4, "Launched preinit instance, pid=%d\n", (int) preinit_proc.pid);
 132 }