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