init.c

   1 /*
   2  * this code is protected by the GNU affero GPLv3
   3  * author:Sylvain BERTRAND <sylvain.bertrand AT legeek DOT net>
   4  */
   5 #include <ulinux/compiler_misc.h>
   6 #include <ulinux/compiler_types.h>
   7 #include <ulinux/sysc.h>
   8 #include <ulinux/types.h>
   9 #include <ulinux/error.h>
  10 #include <ulinux/signal/signal.h>
  11 #include <ulinux/signal/siginfo.h>
  12 #include <ulinux/wait.h>
  13
  14 #define INIT_C
  15 #include "out.h"
  16 #undef INIT_C
  17 #include "ulinux_namespace.h"
  18
  19 static void sigs_setup(void)
  20 {
  21         ul mask;
  22         l r;
  23
  24         mask = ~0;
  25
  26         OUT(PRE "setting up signals...\n");
  27         r = rt_sigprocmask(SIG_BLOCK, &mask, sizeof(mask));
  28         if (ISERR(r)) {
  29                 OUT("ERROR:unable to block all signals (except KILL and STOP)\n");
  30                 exit_group(-1);
  31         }
  32         OUT("done\n");
  33 }
  34
  35 static i sysstart_clone(void)
  36 {
  37         l r;
  38         ul mask;
  39
  40         OUT(PRE "clone and execve /bin/sysstart...\n");
  41         r = clone(SIGCHLD);
  42         if (ISERR(r)) {
  43                 OUT("ERROR(%ld):unable to clone sysinit for /bin/sysstart\n", r);
  44                 exit_group(-1);
  45         }
  46
  47         if (r)
  48                 return (i)r;
  49
  50         mask = ~0;
  51         r = rt_sigprocmask(SIG_UNBLOCK, &mask, sizeof(mask));
  52         if (ISERR(r)) {
  53                 OUT("ERROR(%ld):unable to unblock all signals for /bin/sysstart\n", r);
  54                 exit_group(-1);
  55         }
  56
  57         r = execve("/bin/sysstart", 0);
  58         if(ISERR(r)) {
  59                 OUT("ERROR(%ld):unable to execve /bin/sysstart\n", r);
  60         }
  61         exit_group(-1);
  62 }
  63
  64 #ifndef NO_TTY
  65 static i getty_spawn(void *tty)
  66 {
  67         l r;
  68         ul mask;
  69         void *argv[3];
  70
  71         argv[0] = "bin/agetty";
  72         argv[1] = tty;
  73         argv[2] = 0;
  74
  75         OUT(PRE "getty %s...\n", tty);
  76
  77         r = clone(SIGCHLD);
  78         if (ISERR(r)) {
  79                 OUT("ERROR(%ld):unable to clone for getty(%s)\n", r, tty);
  80                 exit_group(-1);
  81         }
  82
  83         if (r)
  84                 return r;/* return the child process id */
  85
  86         mask = ~0;
  87         r = rt_sigprocmask(SIG_UNBLOCK, &mask, sizeof(mask));
  88         if (ISERR(r)) {
  89                 OUT("ERROR(%ld):unable to unblock all signals for getty(%s)\n", r, tty);
  90                 exit_group(-1);
  91         }
  92
  93         r = setsid();
  94         if (ISERR(r)) {
  95                 OUT("ERROR(%ld):unable to setsid the getty(%s) clone\n", r, tty);
  96                 exit_group(-1);
  97         }
  98
  99         r = execve("/bin/agetty", argv);
 100         if (ISERR(r)) {
 101                 OUT("ERROR(%ld):unable to run /bin/agetty(%s)\n", r, tty);
 102         }
 103         exit_group(-1);
 104 }
 105 #endif
 106
 107 static void sysstart(void)
 108 {
 109         i pid;
 110         l r;
 111
 112         pid = sysstart_clone();
 113         r = waitid(P_PID, pid, 0, WEXITED|WALL);
 114         if (ISERR(r)) {
 115                 OUT("ERROR(%ld):unable to wait for /bin/sysstart to exit\n", r);
 116                 exit_group(-1);
 117         }
 118 }
 119
 120 #ifdef NO_TTY
 121 /* minimal, we don't even have ttys to restart */
 122 static void main_loop(void)
 123 {
 124         loop {
 125                 l r;
 126
 127                 r = waitid(P_ALL, 0, 0, WEXITED|WALL);
 128                 if (ISERR(r)) {
 129                         OUT("ERROR(%ld):unable to wait on orphan process terminations\n", r);
 130                 }
 131         }
 132 }
 133 #else
 134 /* we allow ourself 2 ttys to restart */
 135 static void main_loop(void)
 136 {
 137         i tty1;
 138         i tty2;
 139
 140         tty1 = getty_spawn("tty1");
 141         tty2 = getty_spawn("tty2");
 142
 143         loop {
 144                 struct siginfo siginfo;
 145                 l r;
 146
 147                 r = waitid(P_ALL, 0, &siginfo, WEXITED|WALL);
 148                 if(ISERR(r)) {
 149                         OUT("ERROR(%ld):unable to wait on /bin/agetty clone and orphan process terminations\n", r);
 150                         exit_group(-1);
 151                 }
 152                 if (siginfo.fields.sigchld.pid == tty1)
 153                         tty1 = getty_spawn("tty1");
 154                 else if (siginfo.fields.sigchld.pid == tty2)
 155                         tty2 = getty_spawn("tty2");
 156         }
 157 }
 158 #endif
 159 void _start(void)
 160 {
 161         sigs_setup();
 162         sysstart();
 163         main_loop();
 164 }
 165 /* vim: set ts=4 sw=0 noexpandtab: */