ladybird/AK/StackInfo.cpp
Brian Gianforcaro 1682f0b760 Everything: Move to SPDX license identifiers in all files.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.

See: https://spdx.dev/resources/use/#identifiers

This was done with the `ambr` search and replace tool.

 ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 11:22:27 +02:00

64 lines
1.9 KiB
C++

/*
* Copyright (c) 2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Assertions.h>
#include <AK/StackInfo.h>
#include <stdio.h>
#include <string.h>
#ifdef __serenity__
# include <serenity.h>
#elif defined(__linux__) or defined(__APPLE__)
# include <pthread.h>
#endif
namespace AK {
StackInfo::StackInfo()
{
#ifdef __serenity__
if (get_stack_bounds(&m_base, &m_size) < 0) {
perror("get_stack_bounds");
VERIFY_NOT_REACHED();
}
#elif __linux__
int rc;
pthread_attr_t attr = {};
if ((rc = pthread_getattr_np(pthread_self(), &attr)) != 0) {
fprintf(stderr, "pthread_getattr_np: %s\n", strerror(-rc));
VERIFY_NOT_REACHED();
}
if ((rc = pthread_attr_getstack(&attr, (void**)&m_base, &m_size)) != 0) {
fprintf(stderr, "pthread_attr_getstack: %s\n", strerror(-rc));
VERIFY_NOT_REACHED();
}
pthread_attr_destroy(&attr);
#elif __APPLE__
// NOTE: !! On MacOS, pthread_get_stackaddr_np gives the TOP of the stack, not the bottom!
FlatPtr top_of_stack = (FlatPtr)pthread_get_stackaddr_np(pthread_self());
m_size = (size_t)pthread_get_stacksize_np(pthread_self());
// https://github.com/rust-lang/rust/issues/43347#issuecomment-316783599
// https://developer.apple.com/library/archive/qa/qa1419/_index.html
//
// MacOS seems inconsistent on what stack size is given for the main thread.
// According to the Apple docs, default for main thread is 8MB, and default for
// other threads is 512KB
constexpr size_t eight_megabytes = 0x800000;
if (pthread_main_np() == 1 && m_size < eight_megabytes) {
// Assume no one messed with stack size linker options for the main thread,
// and just set it to 8MB.
m_size = eight_megabytes;
}
m_base = top_of_stack - m_size;
#else
VERIFY_NOT_REACHED();
#endif
m_top = m_base + m_size;
}
}