diff options
Diffstat (limited to 'libexec/rtld-elf/i386/lockdflt.c')
-rw-r--r-- | libexec/rtld-elf/i386/lockdflt.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/libexec/rtld-elf/i386/lockdflt.c b/libexec/rtld-elf/i386/lockdflt.c new file mode 100644 index 0000000..6f278c3 --- /dev/null +++ b/libexec/rtld-elf/i386/lockdflt.c @@ -0,0 +1,94 @@ +/*- + * Copyright 1999 John D. Polstra. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * $FreeBSD$ + */ + +/* + * Default thread locking implementation for the dynamic linker. It + * is used until the client registers a different implementation with + * dllockinit(). The default implementation does mutual exclusion + * by blocking the SIGVTALRM, SIGPROF, and SIGALRM signals. This is + * based on the observation that most userland thread packages use one + * of these signals to support preemption. + */ + +#include <dlfcn.h> +#include <signal.h> +#include <stdlib.h> + +#include "debug.h" +#include "rtld.h" + +typedef struct Struct_LockDflt { + sigset_t lock_mask; + sigset_t old_mask; + int depth; +} LockDflt; + +void +lockdflt_acquire(void *lock) +{ + LockDflt *l = (LockDflt *)lock; + sigprocmask(SIG_BLOCK, &l->lock_mask, &l->old_mask); + assert(l->depth == 0); + l->depth++; +} + +void * +lockdflt_create(void *context) +{ + LockDflt *l; + + l = NEW(LockDflt); + l->depth = 0; + sigemptyset(&l->lock_mask); + sigaddset(&l->lock_mask, SIGVTALRM); + sigaddset(&l->lock_mask, SIGPROF); + sigaddset(&l->lock_mask, SIGALRM); + return l; +} + +void +lockdflt_destroy(void *lock) +{ + LockDflt *l = (LockDflt *)lock; + free(l); +} + +void +lockdflt_release(void *lock) +{ + LockDflt *l = (LockDflt *)lock; + assert(l->depth == 1); + l->depth--; + sigprocmask(SIG_SETMASK, &l->old_mask, NULL); +} + +void +lockdflt_init(void) +{ + dllockinit(NULL, lockdflt_create, lockdflt_acquire, lockdflt_acquire, + lockdflt_release, lockdflt_destroy, NULL); +} |