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/*
* context_save.c -- write out the updated context file
*
* This code is Copyright (c) 2002, by the authors of nmh. See the
* COPYRIGHT file in the root directory of the nmh distribution for
* complete copyright information.
*/
#include <h/mh.h>
#include <h/signals.h>
/*
* static prototypes
*/
static int m_chkids(void);
void
context_save (void)
{
int action;
register struct node *np;
FILE *out;
sigset_t set, oset;
int failed_to_lock = 0;
/* No context in use -- silently ignore any changes! */
if (!ctxpath)
return;
if (!(ctxflags & CTXMOD))
return;
ctxflags &= ~CTXMOD;
if ((action = m_chkids ()) > 0)
return; /* child did it for us */
/* block a few signals */
sigemptyset (&set);
sigaddset (&set, SIGHUP);
sigaddset (&set, SIGINT);
sigaddset (&set, SIGQUIT);
sigaddset (&set, SIGTERM);
sigprocmask (SIG_BLOCK, &set, &oset);
if (!(out = lkfopendata (ctxpath, "w", &failed_to_lock))) {
if (failed_to_lock) {
adios (ctxpath, "failed to lock");
} else {
adios (ctxpath, "unable to write");
}
}
for (np = m_defs; np; np = np->n_next)
if (np->n_context)
fprintf (out, "%s: %s\n", np->n_name, np->n_field);
lkfclosedata (out, ctxpath);
sigprocmask (SIG_SETMASK, &oset, &set); /* reset the signal mask */
if (action == 0)
/* This must be _exit(), not exit(), because the child didn't
call unregister_for_removal() in m_chkids(). */
_exit (0); /* we are child, time to die */
}
/*
* This hack brought to you so we can handle set[ug]id MH programs.
* If we return -1, then no fork is made, we update .mh_profile
* normally, and return to the caller normally. If we return 0,
* then the child is executing, .mh_profile is modified after
* we set our [ug]ids to the norm. If we return > 0, then the
* parent is executed and .mh_profile has already be modified.
* We can just return to the caller immediately.
*/
static int
m_chkids (void)
{
int i;
pid_t pid;
if (getuid () == geteuid ())
return (-1);
for (i = 0; (pid = fork ()) == -1 && i < 5; i++)
sleep (5);
switch (pid) {
case -1:
break;
case 0:
/* It's not necessary to call unregister_for_removal(0)
because the child calls _exit() in context_save(). */
break;
default:
pidwait (pid, -1);
break;
}
return pid;
}
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