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/*
+----------------------------------------------------------------------+
| Zend OPcache |
+----------------------------------------------------------------------+
| Copyright (c) The PHP Group |
+----------------------------------------------------------------------+
| This source file is subject to version 3.01 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
| available through the world-wide-web at the following url: |
| https://www.php.net/license/3_01.txt |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| license@php.net so we can mail you a copy immediately. |
+----------------------------------------------------------------------+
| Authors: Andi Gutmans <andi@php.net> |
| Zeev Suraski <zeev@php.net> |
| Stanislav Malyshev <stas@zend.com> |
| Dmitry Stogov <dmitry@php.net> |
+----------------------------------------------------------------------+
*/
#include "zend_shared_alloc.h"
#ifdef HAVE_JIT
# include "jit/zend_jit.h"
#endif
#ifdef USE_MMAP
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#ifdef __APPLE__
#include <mach/vm_statistics.h>
#endif
#include "zend_execute.h"
#ifdef HAVE_PROCCTL
#include <sys/procctl.h>
#endif
#if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
# define MAP_ANONYMOUS MAP_ANON
#endif
#if defined(MAP_ALIGNED_SUPER)
# include <sys/types.h>
# include <sys/sysctl.h>
# include <sys/user.h>
# define MAP_HUGETLB MAP_ALIGNED_SUPER
#endif
#if defined(HAVE_JIT) && (defined(__linux__) || defined(__FreeBSD__)) && (defined(__x86_64__) || defined (__aarch64__)) && !defined(__SANITIZE_ADDRESS__)
static void *find_prefered_mmap_base(size_t requested_size)
{
size_t huge_page_size = 2 * 1024 * 1024;
uintptr_t last_free_addr = huge_page_size;
uintptr_t last_candidate = (uintptr_t)MAP_FAILED;
uintptr_t start, end, text_start = 0;
#if defined(__linux__)
FILE *f;
char buffer[MAXPATHLEN];
f = fopen("/proc/self/maps", "r");
if (!f) {
return MAP_FAILED;
}
while (fgets(buffer, MAXPATHLEN, f) && sscanf(buffer, "%lx-%lx", &start, &end) == 2) {
/* Don't place the segment directly before or after the heap segment. Due to an selinux bug,
* a segment directly preceding or following the heap is interpreted as heap memory, which
* will result in an execheap violation for the JIT.
* See https://bugzilla.kernel.org/show_bug.cgi?id=218258. */
bool heap_segment = strstr(buffer, "[heap]") != NULL;
if (heap_segment) {
uintptr_t start_base = start & ~(huge_page_size - 1);
if (last_free_addr + requested_size >= start_base) {
last_free_addr = ZEND_MM_ALIGNED_SIZE_EX(end + huge_page_size, huge_page_size);
continue;
}
}
if ((uintptr_t)execute_ex >= start) {
/* the current segment lays before PHP .text segment or PHP .text segment itself */
/*Search for candidates at the end of the free segment near the .text segment
to prevent candidates from being missed due to large hole*/
if (last_free_addr + requested_size <= start) {
last_candidate = ZEND_MM_ALIGNED_SIZE_EX(start - requested_size, huge_page_size);
if (last_candidate + requested_size > start) {
last_candidate -= huge_page_size;
}
}
if ((uintptr_t)execute_ex < end) {
/* the current segment is PHP .text segment itself */
if (last_candidate != (uintptr_t)MAP_FAILED) {
if (end - last_candidate < UINT32_MAX) {
/* we have found a big enough hole before the text segment */
break;
}
last_candidate = (uintptr_t)MAP_FAILED;
}
text_start = start;
}
} else {
/* the current segment lays after PHP .text segment */
if (last_free_addr + requested_size - text_start > UINT32_MAX) {
/* the current segment and the following segments lay too far from PHP .text segment */
break;
}
if (last_free_addr + requested_size <= start) {
last_candidate = last_free_addr;
break;
}
}
last_free_addr = ZEND_MM_ALIGNED_SIZE_EX(end, huge_page_size);
if (heap_segment) {
last_free_addr += huge_page_size;
}
}
fclose(f);
#elif defined(__FreeBSD__)
size_t s = 0;
int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_VMMAP, getpid()};
if (sysctl(mib, 4, NULL, &s, NULL, 0) == 0) {
s = s * 4 / 3;
void *addr = mmap(NULL, s, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
if (addr != MAP_FAILED) {
if (sysctl(mib, 4, addr, &s, NULL, 0) == 0) {
start = (uintptr_t)addr;
end = start + s;
while (start < end) {
struct kinfo_vmentry *entry = (struct kinfo_vmentry *)start;
size_t sz = entry->kve_structsize;
if (sz == 0) {
break;
}
uintptr_t e_start = entry->kve_start;
uintptr_t e_end = entry->kve_end;
if ((uintptr_t)execute_ex >= e_start) {
/* the current segment lays before PHP .text segment or PHP .text segment itself */
if (last_free_addr + requested_size <= e_start) {
last_candidate = ZEND_MM_ALIGNED_SIZE_EX(e_start - requested_size, huge_page_size);
if (last_candidate + requested_size > e_start) {
last_candidate -= huge_page_size;
}
}
if ((uintptr_t)execute_ex < e_end) {
/* the current segment is PHP .text segment itself */
if (last_candidate != (uintptr_t)MAP_FAILED) {
if (e_end - last_candidate < UINT32_MAX) {
/* we have found a big enough hole before the text segment */
break;
}
last_candidate = (uintptr_t)MAP_FAILED;
}
text_start = e_start;
}
} else {
/* the current segment lays after PHP .text segment */
if (last_free_addr + requested_size - text_start > UINT32_MAX) {
/* the current segment and the following segments lay too far from PHP .text segment */
break;
}
if (last_free_addr + requested_size <= e_start) {
last_candidate = last_free_addr;
break;
}
}
last_free_addr = ZEND_MM_ALIGNED_SIZE_EX(e_end, huge_page_size);
start += sz;
}
}
munmap(addr, s);
}
}
#endif
return (void*)last_candidate;
}
#endif
static int create_segments(size_t requested_size, zend_shared_segment ***shared_segments_p, int *shared_segments_count, const char **error_in)
{
zend_shared_segment *shared_segment;
int flags = PROT_READ | PROT_WRITE, fd = -1;
void *p;
#if defined(HAVE_PROCCTL) && defined(PROC_WXMAP_CTL)
int enable_wxmap = PROC_WX_MAPPINGS_PERMIT;
if (procctl(P_PID, getpid(), PROC_WXMAP_CTL, &enable_wxmap) == -1) {
return ALLOC_FAILURE;
}
#endif
#ifdef PROT_MPROTECT
flags |= PROT_MPROTECT(PROT_EXEC);
#endif
#ifdef VM_MAKE_TAG
/* allows tracking segments via tools such as vmmap */
fd = VM_MAKE_TAG(251U);
#endif
#ifdef PROT_MAX
flags |= PROT_MAX(PROT_READ | PROT_WRITE | PROT_EXEC);
#endif
#if defined(HAVE_JIT) && (defined(__linux__) || defined(__FreeBSD__)) && (defined(__x86_64__) || defined (__aarch64__)) && !defined(__SANITIZE_ADDRESS__)
void *hint;
if (JIT_G(enabled) && JIT_G(buffer_size)
&& zend_jit_check_support() == SUCCESS) {
hint = find_prefered_mmap_base(requested_size);
} else {
/* Do not use a hint if JIT is not enabled, as this profits only JIT and
* this is potentially unsafe when the only suitable candidate is just
* after the heap (e.g. in non-PIE builds) (GH-13775). */
hint = MAP_FAILED;
}
if (hint != MAP_FAILED) {
# ifdef MAP_HUGETLB
size_t huge_page_size = 2 * 1024 * 1024;
if (requested_size >= huge_page_size && requested_size % huge_page_size == 0) {
p = mmap(hint, requested_size, flags, MAP_SHARED|MAP_ANONYMOUS|MAP_HUGETLB|MAP_FIXED, -1, 0);
if (p != MAP_FAILED) {
goto success;
}
}
#endif
p = mmap(hint, requested_size, flags, MAP_SHARED|MAP_ANONYMOUS|MAP_FIXED, -1, 0);
if (p != MAP_FAILED) {
goto success;
}
}
#endif
#ifdef MAP_HUGETLB
size_t huge_page_size = 2 * 1024 * 1024;
/* Try to allocate huge pages first to reduce dTLB misses.
* OSes has to be configured properly
* on Linux
* (e.g. https://wiki.debian.org/Hugepages#Enabling_HugeTlbPage)
* You may verify huge page usage with the following command:
* `grep "Huge" /proc/meminfo`
* on FreeBSD
* sysctl vm.pmap.pg_ps_enabled entry
* (boot time config only, but enabled by default on most arches).
*/
if (requested_size >= huge_page_size && requested_size % huge_page_size == 0) {
# if defined(__x86_64__) && defined(MAP_32BIT)
/* to got HUGE PAGES in low 32-bit address we have to reserve address
space and then remap it using MAP_HUGETLB */
p = mmap(NULL, requested_size, flags, MAP_SHARED|MAP_ANONYMOUS|MAP_32BIT, fd, 0);
if (p != MAP_FAILED) {
munmap(p, requested_size);
p = (void*)(ZEND_MM_ALIGNED_SIZE_EX((ptrdiff_t)p, huge_page_size));
p = mmap(p, requested_size, flags, MAP_SHARED|MAP_ANONYMOUS|MAP_32BIT|MAP_HUGETLB|MAP_FIXED, -1, 0);
if (p != MAP_FAILED) {
goto success;
} else {
p = mmap(NULL, requested_size, flags, MAP_SHARED|MAP_ANONYMOUS|MAP_32BIT, fd, 0);
if (p != MAP_FAILED) {
goto success;
}
}
}
# endif
p = mmap(0, requested_size, flags, MAP_SHARED|MAP_ANONYMOUS|MAP_HUGETLB, fd, 0);
if (p != MAP_FAILED) {
goto success;
}
}
#elif defined(PREFER_MAP_32BIT) && defined(__x86_64__) && defined(MAP_32BIT)
p = mmap(NULL, requested_size, flags, MAP_SHARED|MAP_ANONYMOUS|MAP_32BIT, fd, 0);
if (p != MAP_FAILED) {
goto success;
}
#endif
p = mmap(0, requested_size, flags, MAP_SHARED|MAP_ANONYMOUS, fd, 0);
if (p == MAP_FAILED) {
*error_in = "mmap";
return ALLOC_FAILURE;
}
success: ZEND_ATTRIBUTE_UNUSED;
*shared_segments_count = 1;
*shared_segments_p = (zend_shared_segment **) calloc(1, sizeof(zend_shared_segment) + sizeof(void *));
if (!*shared_segments_p) {
munmap(p, requested_size);
*error_in = "calloc";
return ALLOC_FAILURE;
}
shared_segment = (zend_shared_segment *)((char *)(*shared_segments_p) + sizeof(void *));
(*shared_segments_p)[0] = shared_segment;
shared_segment->p = p;
shared_segment->pos = 0;
shared_segment->size = requested_size;
return ALLOC_SUCCESS;
}
static int detach_segment(zend_shared_segment *shared_segment)
{
munmap(shared_segment->p, shared_segment->size);
return 0;
}
static size_t segment_type_size(void)
{
return sizeof(zend_shared_segment);
}
const zend_shared_memory_handlers zend_alloc_mmap_handlers = {
create_segments,
detach_segment,
segment_type_size
};
#endif /* USE_MMAP */
|