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Add a wrapper for the execve() system call that arranges for the current 

thread sigal mask to be propagated into the new process image.
This commit is contained in:
nathanw 2003-03-14 22:27:34 +00:00
parent 022a762c83
commit a25b9285d9
1 changed files with 47 additions and 2 deletions
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49
lib/libpthread/pthread_sig.c
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@ -1,4 +1,4 @@
/* $NetBSD: pthread_sig.c,v 1.11 2003/03/08 08:03:35 lukem Exp $ */
/* $NetBSD: pthread_sig.c,v 1.12 2003/03/14 22:27:34 nathanw Exp $ */
/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
@ -37,7 +37,7 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: pthread_sig.c,v 1.11 2003/03/08 08:03:35 lukem Exp $");
__RCSID("$NetBSD: pthread_sig.c,v 1.12 2003/03/14 22:27:34 nathanw Exp $");
/* We're interposing a specific version of the signal interface. */
#define __LIBC12_SOURCE__
@ -105,7 +105,10 @@ pthread__signal_tramp(int, int, void (*)(int, int, struct sigcontext *),
static int firstsig(const sigset_t *);
int _sys_execve(const char *, char *const [], char *const []);
__strong_alias(__libc_thr_sigsetmask,pthread_sigmask)
__strong_alias(__exeve,execve)
void
pthread__signal_init(void)
@ -893,3 +896,45 @@ pthread__signal_tramp(int sig, int code,
/*NOTREACHED*//*CONSTCOND*/
assert(0);
}
/*
* The execve() system call and the libc exec*() calls that use it are
* specified to propagate the signal mask of the current thread to the
* initial thread of the new process image. Since thread signal masks
* are maintained in userlevel, this wrapper is necessary to give the
* kernel the correct value.
*/
int
execve(const char *path, char *const argv[], char *const envp[])
{
pthread_t self;
int ret;
self = pthread__self();
/*
* Don't acquire pt_process_siglock, even though it seems like
* the right thing to do. The most common reason to be here is
* that we're on the child side of a fork() or vfork()
* call. In either case, another thread could have held
* pt_process_siglock at the moment of forking, and acquiring
* it here would cause us to deadlock. Additionally, in the
* case of vfork(), acquiring the lock here would cause it to
* be locked in the parent's address space and cause a
* deadlock there the next time a signal routine is called.
*
* The remaining case is where a live multithreaded program
* calls exec*() from one of several threads with no explicit
* synchronization. It may get the wrong process sigmask in
* the new process image if another thread executes a signal
* routine between the sigprocmask and the _sys_execve()
* call. I don't have much sympathy for such a program.
*/
__sigprocmask14(SIG_SETMASK, &self->pt_sigmask, NULL);
ret = _sys_execve(path, argv, envp);
/* Normally, we shouldn't get here; this is an error condition. */
__sigprocmask14(SIG_SETMASK, &pt_process_sigmask, NULL);
return ret;
}