Module Name: src
Committed By: martin
Date: Wed May 13 18:08:38 UTC 2020
Modified Files:
src/lib/libc/gen [netbsd-9]: pthread_atfork.c
src/libexec/ld.elf_so [netbsd-9]: rtld.c rtld.h symbols.map
Log Message:
Pull up following revision(s) (requested by chs in ticket #907):
libexec/ld.elf_so/rtld.c: revision 1.205
libexec/ld.elf_so/rtld.h: revision 1.140
libexec/ld.elf_so/symbols.map: revision 1.3
libexec/ld.elf_so/symbols.map: revision 1.4
lib/libc/gen/pthread_atfork.c: revision 1.13
lib/libc/gen/pthread_atfork.c: revision 1.14
libexec/ld.elf_so/rtld.h: revision 1.139
libexec/ld.elf_so/rtld.c: revision 1.204
Introduce intermediate locking for fork, so that the dynamic linker is
in a consistent state. This most importantly avoids races between dlopen
and friends and fork, potentially resulting in dead locks in the child
when it itself tries to acquire locks.
Rename __atomic_fork to __locked_fork and give it &errno as argument.
rtld and libc use different storage, so the initial version would
incorrectly report the failure reason for fork().
There is still a small race condition inside ld.elf_so as it doesn't use
thread-safe errno internally, but that's a more contained internal
issue.
To generate a diff of this commit:
cvs rdiff -u -r1.10 -r1.10.18.1 src/lib/libc/gen/pthread_atfork.c
cvs rdiff -u -r1.197.2.3 -r1.197.2.4 src/libexec/ld.elf_so/rtld.c
cvs rdiff -u -r1.136 -r1.136.2.1 src/libexec/ld.elf_so/rtld.h
cvs rdiff -u -r1.2 -r1.2.8.1 src/libexec/ld.elf_so/symbols.map
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/gen/pthread_atfork.c
diff -u src/lib/libc/gen/pthread_atfork.c:1.10 src/lib/libc/gen/pthread_atfork.c:1.10.18.1
--- src/lib/libc/gen/pthread_atfork.c:1.10 Tue Jan 20 18:31:25 2015
+++ src/lib/libc/gen/pthread_atfork.c Wed May 13 18:08:38 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: pthread_atfork.c,v 1.10 2015/01/20 18:31:25 christos Exp $ */
+/* $NetBSD: pthread_atfork.c,v 1.10.18.1 2020/05/13 18:08:38 martin Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: pthread_atfork.c,v 1.10 2015/01/20 18:31:25 christos Exp $");
+__RCSID("$NetBSD: pthread_atfork.c,v 1.10.18.1 2020/05/13 18:08:38 martin Exp $");
#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
@@ -48,6 +48,13 @@ __weak_alias(fork, _fork)
#endif /* __weak_alias */
pid_t __fork(void); /* XXX */
+pid_t __locked_fork(int *) __weak; /* XXX */
+
+pid_t
+__locked_fork(int *my_errno)
+{
+ return __fork();
+}
struct atfork_callback {
SIMPLEQ_ENTRY(atfork_callback) next;
@@ -157,7 +164,7 @@ fork(void)
SIMPLEQ_FOREACH(iter, &prepareq, next)
(*iter->fn)();
- ret = __fork();
+ ret = __locked_fork(&errno);
if (ret != 0) {
/*
Index: src/libexec/ld.elf_so/rtld.c
diff -u src/libexec/ld.elf_so/rtld.c:1.197.2.3 src/libexec/ld.elf_so/rtld.c:1.197.2.4
--- src/libexec/ld.elf_so/rtld.c:1.197.2.3 Sun Mar 8 10:22:29 2020
+++ src/libexec/ld.elf_so/rtld.c Wed May 13 18:08:38 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: rtld.c,v 1.197.2.3 2020/03/08 10:22:29 martin Exp $ */
+/* $NetBSD: rtld.c,v 1.197.2.4 2020/05/13 18:08:38 martin Exp $ */
/*
* Copyright 1996 John D. Polstra.
@@ -40,7 +40,7 @@
#include <sys/cdefs.h>
#ifndef lint
-__RCSID("$NetBSD: rtld.c,v 1.197.2.3 2020/03/08 10:22:29 martin Exp $");
+__RCSID("$NetBSD: rtld.c,v 1.197.2.4 2020/05/13 18:08:38 martin Exp $");
#endif /* not lint */
#include <sys/param.h>
@@ -1530,6 +1530,23 @@ __dl_cxa_refcount(void *addr, ssize_t de
_rtld_exclusive_exit(&mask);
}
+pid_t __fork(void);
+
+__dso_public pid_t
+__locked_fork(int *my_errno)
+{
+ sigset_t mask;
+ pid_t result;
+
+ _rtld_exclusive_enter(&mask);
+ result = __fork();
+ if (result == -1)
+ *my_errno = errno;
+ _rtld_exclusive_exit(&mask);
+
+ return result;
+}
+
/*
* Error reporting function. Use it like printf. If formats the message
* into a buffer, and sets things up so that the next call to dlerror()
Index: src/libexec/ld.elf_so/rtld.h
diff -u src/libexec/ld.elf_so/rtld.h:1.136 src/libexec/ld.elf_so/rtld.h:1.136.2.1
--- src/libexec/ld.elf_so/rtld.h:1.136 Sun Dec 30 01:48:37 2018
+++ src/libexec/ld.elf_so/rtld.h Wed May 13 18:08:38 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: rtld.h,v 1.136 2018/12/30 01:48:37 christos Exp $ */
+/* $NetBSD: rtld.h,v 1.136.2.1 2020/05/13 18:08:38 martin Exp $ */
/*
* Copyright 1996 John D. Polstra.
@@ -347,6 +347,8 @@ __dso_public int dl_iterate_phdr(int (*)
__dso_public void *_dlauxinfo(void) __pure;
__dso_public void __dl_cxa_refcount(void *addr, ssize_t delta);
+__dso_public pid_t __locked_fork(int *);
+
#if defined(__ARM_EABI__) && !defined(__ARM_DWARF_EH__)
/*
* This is used by libgcc to find the start and length of the exception table
Index: src/libexec/ld.elf_so/symbols.map
diff -u src/libexec/ld.elf_so/symbols.map:1.2 src/libexec/ld.elf_so/symbols.map:1.2.8.1
--- src/libexec/ld.elf_so/symbols.map:1.2 Tue Jul 11 15:21:35 2017
+++ src/libexec/ld.elf_so/symbols.map Wed May 13 18:08:38 2020
@@ -23,5 +23,6 @@
___tls_get_addr;
__gnu_Unwind_Find_exidx;
__dl_cxa_refcount;
+ __locked_fork;
local: *;
};
