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
  32 static struct uloop_process preinit_proc;
  33 static struct uloop_process plugd_proc;
  34
  35 static void
  36 check_dbglvl(void)
  37 {
  38         FILE *fp = fopen("/tmp/debug_level", "r");
  39         int lvl = 0;
  40
  41         if (!fp)
  42                 return;
  43         if (fscanf(fp, "%d", &lvl) == EOF)
  44                 ERROR("failed to read debug level\n");
  45         fclose(fp);
  46         unlink("/tmp/debug_level");
  47
  48         if (lvl > 0 && lvl < 5)
  49                 debug = lvl;
  50 }
  51
  52 static void
  53 spawn_procd(struct uloop_process *proc, int ret)
  54 {
  55         char *wdt_fd = watchdog_fd();
  56         char *argv[] = { "/sbin/procd", NULL};
  57         struct stat s;
  58         char dbg[2];
  59
  60         if (plugd_proc.pid > 0)
  61                 kill(plugd_proc.pid, SIGKILL);
  62
  63         if (!stat("/tmp/sysupgrade", &s))
  64                 while (true)
  65                         sleep(1);
  66
  67         unsetenv("INITRAMFS");
  68         unsetenv("PREINIT");
  69         unlink("/tmp/.preinit");
  70         DEBUG(2, "Exec to real procd now\n");
  71         if (wdt_fd)
  72                 setenv("WDTFD", wdt_fd, 1);
  73         check_dbglvl();
  74         if (debug > 0) {
  75                 snprintf(dbg, 2, "%d", debug);
  76                 setenv("DBGLVL", dbg, 1);
  77         }
  78
  79         execvp(argv[0], argv);
  80 }
  81
  82 static void
  83 plugd_proc_cb(struct uloop_process *proc, int ret)
  84 {
  85         proc->pid = 0;
  86 }
  87
  88 void
  89 preinit(void)
  90 {
  91         char *init[] = { "/bin/sh", "/etc/preinit", NULL };
  92         char *plug[] = { "/sbin/procd", "-h", "/etc/hotplug-preinit.json", NULL };
  93         int fd;
  94
  95         LOG("- preinit -\n");
  96
  97         plugd_proc.cb = plugd_proc_cb;
  98         plugd_proc.pid = fork();
  99         if (!plugd_proc.pid) {
 100                 execvp(plug[0], plug);
 101                 ERROR("Failed to start plugd\n");
 102                 exit(-1);
 103         }
 104         if (plugd_proc.pid <= 0) {
 105                 ERROR("Failed to start new plugd instance\n");
 106                 return;
 107         }
 108         uloop_process_add(&plugd_proc);
 109
 110         setenv("PREINIT", "1", 1);
 111
 112         fd = creat("/tmp/.preinit", 0600);
 113
 114         if (fd < 0)
 115                 ERROR("Failed to create sentinel file\n");
 116         else
 117                 close(fd);
 118
 119         preinit_proc.cb = spawn_procd;
 120         preinit_proc.pid = fork();
 121         if (!preinit_proc.pid) {
 122                 execvp(init[0], init);
 123                 ERROR("Failed to start preinit\n");
 124                 exit(-1);
 125         }
 126         if (preinit_proc.pid <= 0) {
 127                 ERROR("Failed to start new preinit instance\n");
 128                 return;
 129         }
 130         uloop_process_add(&preinit_proc);
 131
 132         DEBUG(4, "Launched preinit instance, pid=%d\n", (int) preinit_proc.pid);
 133 }