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Fix pthread_getattr_np for the main thread.

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On most architectures the kernel subtracts a random offset to the stack
pointer in create_elf_tables by calling arch_align_stack before writing
the auxval table and so on. On all but x86 this doesn't cause a problem
because the random offset is less than a page, but on x86 it's up to two
pages. This means that our old technique of rounding the stack pointer
doesn't work. (Our old implementation of that technique was wrong too.)

It's also incorrect to assume that the main thread's stack base and size
are constant. Likewise to assume that the main thread has a guard page.
The main thread is not like other threads.

This patch switches to reading /proc/self/maps (and checking RLIMIT_STACK)
whenever we're asked.

Bug: 17111575
Signed-off-by: Fengwei Yin <fengwei.yin@intel.com>
Change-Id: I1d4dbffe7bc7bda1d353c3a295dbf68d29f63158
This commit is contained in:
Elliott Hughes 2014-08-25 17:26:50 -07:00
parent a4a8c4feb8
commit 57b7a6110e
16 changed files with 169 additions and 236 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
libc/arch-arm/arm.mk
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@ -53,7 +53,6 @@ libc_bionic_src_files_arm += \
arch-arm/bionic/atomics_arm.c \
arch-arm/bionic/__bionic_clone.S \
arch-arm/bionic/_exit_with_stack_teardown.S \
arch-arm/bionic/__get_sp.S \
arch-arm/bionic/libgcc_compat.c \
arch-arm/bionic/memcmp.S \
arch-arm/bionic/_setjmp.S \

34
libc/arch-arm/bionic/__get_sp.S
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@ -1,34 +0,0 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/
#include <private/bionic_asm.h>
ENTRY_PRIVATE(__get_sp)
mov r0, sp
bx lr
END(__get_sp)

1
libc/arch-arm64/arm64.mk
View File

@ -29,7 +29,6 @@ libc_common_src_files_arm64 += \
libc_bionic_src_files_arm64 := \
arch-arm64/bionic/__bionic_clone.S \
arch-arm64/bionic/_exit_with_stack_teardown.S \
arch-arm64/bionic/__get_sp.S \
arch-arm64/bionic/__rt_sigreturn.S \
arch-arm64/bionic/_setjmp.S \
arch-arm64/bionic/setjmp.S \

34
libc/arch-arm64/bionic/__get_sp.S
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@ -1,34 +0,0 @@
/*
* Copyright (C) 2013 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/
#include <private/bionic_asm.h>
ENTRY_PRIVATE(__get_sp)
mov x0, sp
ret
END(__get_sp)

34
libc/arch-mips/bionic/__get_sp.S
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@ -1,34 +0,0 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/
#include <private/bionic_asm.h>
ENTRY_PRIVATE(__get_sp)
move v0, sp
j ra
END(__get_sp)

1
libc/arch-mips/mips.mk
View File

@ -54,7 +54,6 @@ libc_bionic_src_files_mips += \
arch-mips/bionic/bzero.S \
arch-mips/bionic/cacheflush.cpp \
arch-mips/bionic/_exit_with_stack_teardown.S \
arch-mips/bionic/__get_sp.S \
arch-mips/bionic/_setjmp.S \
arch-mips/bionic/setjmp.S \
arch-mips/bionic/sigsetjmp.S \

34
libc/arch-mips64/bionic/__get_sp.S
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@ -1,34 +0,0 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/
#include <private/bionic_asm.h>
ENTRY_PRIVATE(__get_sp)
move v0, sp
j ra
END(__get_sp)

34
libc/arch-x86/bionic/__get_sp.S
View File

@ -1,34 +0,0 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/
#include <private/bionic_asm.h>
ENTRY_PRIVATE(__get_sp)
mov %esp, %eax
ret
END(__get_sp)

1
libc/arch-x86/x86.mk
View File

@ -25,7 +25,6 @@ libc_bionic_src_files_x86 := \
libc_bionic_src_files_x86 += \
arch-x86/bionic/__bionic_clone.S \
arch-x86/bionic/_exit_with_stack_teardown.S \
arch-x86/bionic/__get_sp.S \
arch-x86/bionic/_setjmp.S \
arch-x86/bionic/setjmp.S \
arch-x86/bionic/__set_tls.c \

34
libc/arch-x86_64/bionic/__get_sp.S
View File

@ -1,34 +0,0 @@
/*
* Copyright (C) 2013 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*/
#include <private/bionic_asm.h>
ENTRY_PRIVATE(__get_sp)
mov %rsp, %rax
ret
END(__get_sp)

1
libc/arch-x86_64/x86_64.mk
View File

@ -30,7 +30,6 @@ libc_common_src_files_x86_64 += \
libc_bionic_src_files_x86_64 := \
arch-x86_64/bionic/__bionic_clone.S \
arch-x86_64/bionic/_exit_with_stack_teardown.S \
arch-x86_64/bionic/__get_sp.S \
arch-x86_64/bionic/__rt_sigreturn.S \
arch-x86_64/bionic/_setjmp.S \
arch-x86_64/bionic/setjmp.S \

24
libc/bionic/libc_init_common.cpp
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@ -36,7 +36,6 @@
#include <stdlib.h>
#include <sys/auxv.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
#include "private/bionic_auxv.h"
@ -46,7 +45,6 @@
#include "pthread_internal.h"
extern "C" abort_msg_t** __abort_message_ptr;
extern "C" uintptr_t __get_sp(void);
extern "C" int __system_properties_init(void);
extern "C" int __set_tls(void* ptr);
extern "C" int __set_tid_address(int* tid_address);
@ -62,17 +60,6 @@ char** environ;
// Declared in "private/bionic_ssp.h".
uintptr_t __stack_chk_guard = 0;
static size_t get_main_thread_stack_size() {
rlimit stack_limit;
int rlimit_result = getrlimit(RLIMIT_STACK, &stack_limit);
if ((rlimit_result == 0) &&
(stack_limit.rlim_cur != RLIM_INFINITY) &&
(stack_limit.rlim_cur > PTHREAD_STACK_MIN)) {
return (stack_limit.rlim_cur & ~(PAGE_SIZE - 1));
}
return PTHREAD_STACK_SIZE_DEFAULT;
}
/* Init TLS for the initial thread. Called by the linker _before_ libc is mapped
* in memory. Beware: all writes to libc globals from this function will
* apply to linker-private copies and will not be visible from libc later on.
@ -96,16 +83,15 @@ void __libc_init_tls(KernelArgumentBlock& args) {
main_thread.tid = __set_tid_address(&main_thread.tid);
main_thread.set_cached_pid(main_thread.tid);
// Work out the extent of the main thread's stack.
uintptr_t stack_top = (__get_sp() & ~(PAGE_SIZE - 1)) + PAGE_SIZE;
size_t stack_size = get_main_thread_stack_size();
void* stack_bottom = reinterpret_cast<void*>(stack_top - stack_size);
// We don't want to free the main thread's stack even when the main thread exits
// because things like environment variables with global scope live on it.
// We also can't free the pthread_internal_t itself, since that lives on the main
// thread's stack rather than on the heap.
pthread_attr_init(&main_thread.attr);
pthread_attr_setstack(&main_thread.attr, stack_bottom, stack_size);
main_thread.attr.flags = PTHREAD_ATTR_FLAG_USER_ALLOCATED_STACK | PTHREAD_ATTR_FLAG_MAIN_THREAD;
main_thread.attr.guard_size = 0; // The main thread has no guard page.
main_thread.attr.stack_size = 0; // User code should never see this; we'll compute it when asked.
// TODO: the main thread's sched_policy and sched_priority need to be queried.
__init_thread(&main_thread, false);
__init_tls(&main_thread);

51
libc/bionic/pthread_attr.cpp
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@ -28,6 +28,13 @@
#include <pthread.h>
#include <inttypes.h>
#include <stdio.h>
#include <sys/resource.h>
#include "private/bionic_string_utils.h"
#include "private/ErrnoRestorer.h"
#include "private/libc_logging.h"
#include "pthread_internal.h"
int pthread_attr_init(pthread_attr_t* attr) {
@ -90,8 +97,8 @@ int pthread_attr_setstacksize(pthread_attr_t* attr, size_t stack_size) {
}
int pthread_attr_getstacksize(const pthread_attr_t* attr, size_t* stack_size) {
*stack_size = attr->stack_size;
return 0;
void* unused;
return pthread_attr_getstack(attr, &unused, stack_size);
}
int pthread_attr_setstack(pthread_attr_t* attr, void* stack_base, size_t stack_size) {
@ -106,7 +113,42 @@ int pthread_attr_setstack(pthread_attr_t* attr, void* stack_base, size_t stack_s
return 0;
}
static int __pthread_attr_getstack_main_thread(void** stack_base, size_t* stack_size) {
ErrnoRestorer errno_restorer;
// It doesn't matter which thread we are; we're just looking for "[stack]".
FILE* fp = fopen("/proc/self/maps", "re");
if (fp == NULL) {
return errno;
}
char line[BUFSIZ];
while (fgets(line, sizeof(line), fp) != NULL) {
if (ends_with(line, " [stack]\n")) {
uintptr_t lo, hi;
if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR, &lo, &hi) == 2) {
*stack_base = reinterpret_cast<void*>(lo);
*stack_size = hi - lo;
// Does our current RLIMIT_STACK mean we won't actually get everything /proc/maps promises?
rlimit stack_limit;
if (getrlimit(RLIMIT_STACK, &stack_limit) != -1) {
if (*stack_size > stack_limit.rlim_cur) {
*stack_size = stack_limit.rlim_cur;
}
}
fclose(fp);
return 0;
}
}
}
__libc_fatal("No [stack] line found in /proc/self/maps!");
}
int pthread_attr_getstack(const pthread_attr_t* attr, void** stack_base, size_t* stack_size) {
if ((attr->flags & PTHREAD_ATTR_FLAG_MAIN_THREAD) != 0) {
return __pthread_attr_getstack_main_thread(stack_base, stack_size);
}
*stack_base = attr->stack_base;
*stack_size = attr->stack_size;
return 0;
@ -122,9 +164,8 @@ int pthread_attr_getguardsize(const pthread_attr_t* attr, size_t* guard_size) {
return 0;
}
int pthread_getattr_np(pthread_t thid, pthread_attr_t* attr) {
pthread_internal_t* thread = (pthread_internal_t*) thid;
*attr = thread->attr;
int pthread_getattr_np(pthread_t t, pthread_attr_t* attr) {
*attr = reinterpret_cast<pthread_internal_t*>(t)->attr;
return 0;
}

31
libc/private/bionic_string_utils.h Normal file
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@ -0,0 +1,31 @@
/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _BIONIC_STRING_UTILS_H_
#define _BIONIC_STRING_UTILS_H_
#include <string.h>
static inline bool ends_with(const char* s1, const char* s2) {
size_t s1_length = strlen(s1);
size_t s2_length = strlen(s2);
if (s2_length > s1_length) {
return false;
}
return memcmp(s1 + (s1_length - s2_length), s2, s2_length) == 0;
}
#endif // _BIONIC_STRING_UTILS_H_

4
tests/dlfcn_test.cpp
View File

@ -231,10 +231,8 @@ TEST(dlfcn, dladdr) {
// Look in /proc/pid/maps to find out what address we were loaded at.
// TODO: factor /proc/pid/maps parsing out into a class and reuse all over bionic.
void* base_address = NULL;
char path[PATH_MAX];
snprintf(path, sizeof(path), "/proc/%d/maps", getpid());
char line[BUFSIZ];
FILE* fp = fopen(path, "r");
FILE* fp = fopen("/proc/self/maps", "r");
ASSERT_TRUE(fp != NULL);
while (fgets(line, sizeof(line), fp) != NULL) {
uintptr_t start = strtoul(line, 0, 16);

86
tests/pthread_test.cpp
View File

@ -23,6 +23,7 @@
#include <pthread.h>
#include <signal.h>
#include <sys/mman.h>
#include <sys/syscall.h>
#include <time.h>
#include <unistd.h>
@ -816,3 +817,88 @@ TEST(pthread, pthread_mutex_timedlock) {
ASSERT_EQ(0, pthread_mutex_unlock(&m));
ASSERT_EQ(0, pthread_mutex_destroy(&m));
}
TEST(pthread, pthread_attr_getstack__main_thread) {
// This test is only meaningful for the main thread, so make sure we're running on it!
ASSERT_EQ(getpid(), syscall(__NR_gettid));
// Get the main thread's attributes.
pthread_attr_t attributes;
ASSERT_EQ(0, pthread_getattr_np(pthread_self(), &attributes));
// Check that we correctly report that the main thread has no guard page.
size_t guard_size;
ASSERT_EQ(0, pthread_attr_getguardsize(&attributes, &guard_size));
ASSERT_EQ(0U, guard_size); // The main thread has no guard page.
// Get the stack base and the stack size (both ways).
void* stack_base;
size_t stack_size;
ASSERT_EQ(0, pthread_attr_getstack(&attributes, &stack_base, &stack_size));
size_t stack_size2;
ASSERT_EQ(0, pthread_attr_getstacksize(&attributes, &stack_size2));
// The two methods of asking for the stack size should agree.
EXPECT_EQ(stack_size, stack_size2);
// What does /proc/self/maps' [stack] line say?
void* maps_stack_base = NULL;
size_t maps_stack_size = 0;
FILE* fp = fopen("/proc/self/maps", "r");
ASSERT_TRUE(fp != NULL);
char line[BUFSIZ];
while (fgets(line, sizeof(line), fp) != NULL) {
uintptr_t lo, hi;
char name[10];
sscanf(line, "%" PRIxPTR "-%" PRIxPTR " %*4s %*x %*x:%*x %*d %10s", &lo, &hi, name);
if (strcmp(name, "[stack]") == 0) {
maps_stack_base = reinterpret_cast<void*>(lo);
maps_stack_size = hi - lo;
break;
}
}
fclose(fp);
#if defined(__BIONIC__)
// bionic thinks that the stack base and size should correspond to the mapped region.
EXPECT_EQ(maps_stack_base, stack_base);
EXPECT_EQ(maps_stack_size, stack_size);
#else
// glibc doesn't give the true extent for some reason.
#endif
// Both bionic and glibc agree that the high address you can compute from the returned
// values should match what /proc/self/maps says.
void* stack_end = reinterpret_cast<uint8_t*>(stack_base) + stack_size;
void* maps_stack_end = reinterpret_cast<uint8_t*>(maps_stack_base) + maps_stack_size;
EXPECT_EQ(maps_stack_end, stack_end);
//
// What if the rlimit is smaller than the stack's current extent?
//
rlimit rl;
rl.rlim_cur = rl.rlim_max = 1024; // 1KiB. We know the stack must be at least a page already.
rl.rlim_max = RLIM_INFINITY;
ASSERT_EQ(0, setrlimit(RLIMIT_STACK, &rl));
ASSERT_EQ(0, pthread_getattr_np(pthread_self(), &attributes));
ASSERT_EQ(0, pthread_attr_getstack(&attributes, &stack_base, &stack_size));
ASSERT_EQ(0, pthread_attr_getstacksize(&attributes, &stack_size2));
EXPECT_EQ(stack_size, stack_size2);
ASSERT_EQ(1024U, stack_size);
//
// What if the rlimit isn't a whole number of pages?
//
rl.rlim_cur = rl.rlim_max = 6666; // Not a whole number of pages.
rl.rlim_max = RLIM_INFINITY;
ASSERT_EQ(0, setrlimit(RLIMIT_STACK, &rl));
ASSERT_EQ(0, pthread_getattr_np(pthread_self(), &attributes));
ASSERT_EQ(0, pthread_attr_getstack(&attributes, &stack_base, &stack_size));
ASSERT_EQ(0, pthread_attr_getstacksize(&attributes, &stack_size2));
EXPECT_EQ(stack_size, stack_size2);
ASSERT_EQ(6666U, stack_size);
}