diplodocus.org Git - nmh/blob - sbr/context_save.c

   1
   2 /*
   3  * context_save.c -- write out the updated context file
   4  *
   5  * $Id$
   6  */
   7
   8 #include <h/mh.h>
   9 #include <h/signals.h>
  10
  11 /*
  12  * static prototypes
  13  */
  14 static int m_chkids(void);
  15
  16
  17 void
  18 context_save (void)
  19 {
  20     int action;
  21     register struct node *np;
  22     FILE *out;
  23     sigset_t set, oset;
  24
  25     if (!(ctxflags & CTXMOD))
  26         return;
  27     ctxflags &= ~CTXMOD;
  28
  29     if ((action = m_chkids ()) > 0)
  30         return;                 /* child did it for us */
  31
  32     /* block a few signals */
  33     sigemptyset (&set);
  34     sigaddset (&set, SIGHUP);
  35     sigaddset (&set, SIGINT);
  36     sigaddset (&set, SIGQUIT);
  37     sigaddset (&set, SIGTERM);
  38     SIGPROCMASK (SIG_BLOCK, &set, &oset);
  39
  40     if (!(out = fopen (ctxpath, "w")))
  41         adios (ctxpath, "unable to write");
  42     for (np = m_defs; np; np = np->n_next)
  43         if (np->n_context)
  44             fprintf (out, "%s: %s\n", np->n_name, np->n_field);
  45     fclose (out);
  46
  47     SIGPROCMASK (SIG_SETMASK, &oset, &set); /* reset the signal mask */
  48
  49     if (action == 0)
  50         _exit (0);              /* we are child, time to die */
  51 }
  52
  53 /*
  54  * This hack brought to you so we can handle set[ug]id MH programs.
  55  * If we return -1, then no fork is made, we update .mh_profile
  56  * normally, and return to the caller normally.  If we return 0,
  57  * then the child is executing, .mh_profile is modified after
  58  * we set our [ug]ids to the norm.  If we return > 0, then the
  59  * parent is executed and .mh_profile has already be modified.
  60  * We can just return to the caller immediately.
  61  */
  62
  63 static int
  64 m_chkids (void)
  65 {
  66     int i;
  67     pid_t pid;
  68
  69     if (getuid () == geteuid ())
  70         return (-1);
  71
  72     for (i = 0; (pid = fork ()) == -1 && i < 5; i++)
  73         sleep (5);
  74
  75     switch (pid) {
  76         case -1:
  77             break;
  78
  79         case 0:
  80             setgid (getgid ());
  81             setuid (getuid ());
  82             break;
  83
  84         default:
  85             pidwait (pid, -1);
  86             break;
  87     }
  88
  89     return pid;
  90 }