libthr: wrap pdfork(2), same as fork(2).
Without wrapping, rtld services and malloc(3) are not guaranteed to operate correctly in the forked child. Reviewed by: markj MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28088
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4174e45fb4
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@ -238,6 +238,7 @@ enum {
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INTERPOS_fdatasync,
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INTERPOS_clock_nanosleep,
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INTERPOS_distribute_static_tls,
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INTERPOS_pdfork,
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INTERPOS_MAX
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};
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@ -353,6 +354,7 @@ int __sys_msync(void *, __size_t, int);
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int __sys_nanosleep(const struct timespec *, struct timespec *);
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int __sys_open(const char *, int, ...);
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int __sys_openat(int, const char *, int, ...);
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int __sys_pdfork(int *, int);
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int __sys_pselect(int, struct fd_set *, struct fd_set *,
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struct fd_set *, const struct timespec *,
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const __sigset_t *);
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@ -804,6 +804,7 @@ FBSDprivate_1.0 {
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__sys_openat;
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_pathconf;
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__sys_pathconf;
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__sys_pdfork;
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_pipe;
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__sys_pipe;
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_poll;
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@ -82,6 +82,7 @@ interpos_func_t __libc_interposing[INTERPOS_MAX] = {
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SLOT(fdatasync, __sys_fdatasync),
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SLOT(clock_nanosleep, __sys_clock_nanosleep),
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SLOT(distribute_static_tls, __libc_distribute_static_tls),
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SLOT(pdfork, __sys_pdfork),
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};
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#undef SLOT
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46
lib/libc/sys/pdfork.c
Normal file
46
lib/libc/sys/pdfork.c
Normal file
@ -0,0 +1,46 @@
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/*
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* Copyright (c) 2021 The FreeBSD Foundation.
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* All rights reserved.
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*
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* Portions of this software were developed by Konstantin Belousov
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* under sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice(s), this list of conditions and the following disclaimer as
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* the first lines of this file unmodified other than the possible
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* addition of one or more copyright notices.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice(s), this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <unistd.h>
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#include "libc_private.h"
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#pragma weak pdfork
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pid_t
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pdfork(int *fdp, int flags)
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{
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return (((pid_t (*)(int *, int))__libc_interposing[
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INTERPOS_pdfork])(fdp, flags));
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}
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@ -132,10 +132,19 @@ __pthread_cxa_finalize(struct dl_phdr_info *phdr_info)
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_thr_sigact_unload(phdr_info);
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}
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__weak_reference(__thr_fork, _fork);
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enum thr_fork_mode {
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MODE_FORK,
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MODE_PDFORK,
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};
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pid_t
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__thr_fork(void)
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struct thr_fork_args {
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enum thr_fork_mode mode;
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void *fdp;
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int flags;
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};
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static pid_t
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thr_fork_impl(const struct thr_fork_args *a)
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{
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struct pthread *curthread;
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struct pthread_atfork *af;
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@ -144,8 +153,17 @@ __thr_fork(void)
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int was_threaded;
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int rtld_locks[MAX_RTLD_LOCKS];
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if (!_thr_is_inited())
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if (!_thr_is_inited()) {
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switch (a->mode) {
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case MODE_FORK:
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return (__sys_fork());
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case MODE_PDFORK:
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return (__sys_pdfork(a->fdp, a->flags));
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default:
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errno = EDOOFUS;
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return (-1);
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}
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}
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curthread = _get_curthread();
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cancelsave = curthread->no_cancel;
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@ -186,7 +204,19 @@ __thr_fork(void)
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* indirection, the syscall symbol is resolved in
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* _thr_rtld_init() with side-effect free call.
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*/
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switch (a->mode) {
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case MODE_FORK:
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ret = syscall(SYS_fork);
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break;
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case MODE_PDFORK:
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ret = syscall(SYS_pdfork, a->fdp, a->flags);
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break;
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default:
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ret = -1;
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errno = EDOOFUS;
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break;
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}
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if (ret == 0) {
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/* Child process */
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errsave = errno;
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@ -272,3 +302,25 @@ __thr_fork(void)
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return (ret);
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}
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__weak_reference(__thr_fork, _fork);
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pid_t
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__thr_fork(void)
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{
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struct thr_fork_args a;
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a.mode = MODE_FORK;
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return (thr_fork_impl(&a));
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}
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pid_t
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__thr_pdfork(int *fdp, int flags)
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{
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struct thr_fork_args a;
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a.mode = MODE_PDFORK;
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a.fdp = fdp;
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a.flags = flags;
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return (thr_fork_impl(&a));
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}
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@ -984,6 +984,7 @@ void __pthread_distribute_static_tls(size_t offset, void *src, size_t len,
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int *__error_threaded(void) __hidden;
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void __thr_interpose_libc(void) __hidden;
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pid_t __thr_fork(void);
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pid_t __thr_pdfork(int *, int);
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int __thr_setcontext(const ucontext_t *ucp);
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int __thr_sigaction(int sig, const struct sigaction *act,
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struct sigaction *oact) __hidden;
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@ -687,6 +687,7 @@ __thr_interpose_libc(void)
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SLOT(map_stacks_exec);
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SLOT(fdatasync);
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SLOT(clock_nanosleep);
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SLOT(pdfork);
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#undef SLOT
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*(__libc_interposing_slot(
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INTERPOS__pthread_mutex_init_calloc_cb)) =
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