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gcc/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp
H.J. Lu 22a2a09186 libsanitizer: Apply local patches
2022-05-04 11:00:52 +02:00

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//===-- sanitizer_linux_libcdep.cpp ---------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is shared between AddressSanitizer and ThreadSanitizer
// run-time libraries and implements linux-specific functions from
// sanitizer_libc.h.
//===----------------------------------------------------------------------===//
#include "sanitizer_platform.h"
#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
SANITIZER_SOLARIS
#include "sanitizer_allocator_internal.h"
#include "sanitizer_atomic.h"
#include "sanitizer_common.h"
#include "sanitizer_file.h"
#include "sanitizer_flags.h"
#include "sanitizer_freebsd.h"
#include "sanitizer_getauxval.h"
#include "sanitizer_glibc_version.h"
#include "sanitizer_linux.h"
#include "sanitizer_placement_new.h"
#include "sanitizer_procmaps.h"
#if SANITIZER_NETBSD
#define _RTLD_SOURCE // for __lwp_gettcb_fast() / __lwp_getprivate_fast()
#endif
#include <dlfcn.h> // for dlsym()
#include <link.h>
#include <pthread.h>
#include <signal.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <syslog.h>
#if !defined(ElfW)
#define ElfW(type) Elf_##type
#endif
#if SANITIZER_FREEBSD
#include <pthread_np.h>
#include <osreldate.h>
#include <sys/sysctl.h>
#define pthread_getattr_np pthread_attr_get_np
// The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
// that, it was never implemented. So just define it to zero.
#undef MAP_NORESERVE
#define MAP_NORESERVE 0
#endif
#if SANITIZER_NETBSD
#include <sys/sysctl.h>
#include <sys/tls.h>
#include <lwp.h>
#endif
#if SANITIZER_SOLARIS
#include <stdlib.h>
#include <thread.h>
#endif
#if SANITIZER_ANDROID
#include <android/api-level.h>
#if !defined(CPU_COUNT) && !defined(__aarch64__)
#include <dirent.h>
#include <fcntl.h>
struct __sanitizer::linux_dirent {
long d_ino;
off_t d_off;
unsigned short d_reclen;
char d_name[];
};
#endif
#endif
#if !SANITIZER_ANDROID
#include <elf.h>
#include <unistd.h>
#endif
namespace __sanitizer {
SANITIZER_WEAK_ATTRIBUTE int
real_sigaction(int signum, const void *act, void *oldact);
int internal_sigaction(int signum, const void *act, void *oldact) {
#if !SANITIZER_GO
if (&real_sigaction)
return real_sigaction(signum, act, oldact);
#endif
return sigaction(signum, (const struct sigaction *)act,
(struct sigaction *)oldact);
}
void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
uptr *stack_bottom) {
CHECK(stack_top);
CHECK(stack_bottom);
if (at_initialization) {
// This is the main thread. Libpthread may not be initialized yet.
struct rlimit rl;
CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
// Find the mapping that contains a stack variable.
MemoryMappingLayout proc_maps(/*cache_enabled*/true);
if (proc_maps.Error()) {
*stack_top = *stack_bottom = 0;
return;
}
MemoryMappedSegment segment;
uptr prev_end = 0;
while (proc_maps.Next(&segment)) {
if ((uptr)&rl < segment.end) break;
prev_end = segment.end;
}
CHECK((uptr)&rl >= segment.start && (uptr)&rl < segment.end);
// Get stacksize from rlimit, but clip it so that it does not overlap
// with other mappings.
uptr stacksize = rl.rlim_cur;
if (stacksize > segment.end - prev_end) stacksize = segment.end - prev_end;
// When running with unlimited stack size, we still want to set some limit.
// The unlimited stack size is caused by 'ulimit -s unlimited'.
// Also, for some reason, GNU make spawns subprocesses with unlimited stack.
if (stacksize > kMaxThreadStackSize)
stacksize = kMaxThreadStackSize;
*stack_top = segment.end;
*stack_bottom = segment.end - stacksize;
return;
}
uptr stacksize = 0;
void *stackaddr = nullptr;
#if SANITIZER_SOLARIS
stack_t ss;
CHECK_EQ(thr_stksegment(&ss), 0);
stacksize = ss.ss_size;
stackaddr = (char *)ss.ss_sp - stacksize;
#else // !SANITIZER_SOLARIS
pthread_attr_t attr;
pthread_attr_init(&attr);
CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
my_pthread_attr_getstack(&attr, &stackaddr, &stacksize);
pthread_attr_destroy(&attr);
#endif // SANITIZER_SOLARIS
*stack_top = (uptr)stackaddr + stacksize;
*stack_bottom = (uptr)stackaddr;
}
#if !SANITIZER_GO
bool SetEnv(const char *name, const char *value) {
void *f = dlsym(RTLD_NEXT, "setenv");
if (!f)
return false;
typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
setenv_ft setenv_f;
CHECK_EQ(sizeof(setenv_f), sizeof(f));
internal_memcpy(&setenv_f, &f, sizeof(f));
return setenv_f(name, value, 1) == 0;
}
#endif
__attribute__((unused)) static bool GetLibcVersion(int *major, int *minor,
int *patch) {
#ifdef _CS_GNU_LIBC_VERSION
char buf[64];
uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
if (len >= sizeof(buf))
return false;
buf[len] = 0;
static const char kGLibC[] = "glibc ";
if (internal_strncmp(buf, kGLibC, sizeof(kGLibC) - 1) != 0)
return false;
const char *p = buf + sizeof(kGLibC) - 1;
*major = internal_simple_strtoll(p, &p, 10);
*minor = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
*patch = (*p == '.') ? internal_simple_strtoll(p + 1, &p, 10) : 0;
return true;
#else
return false;
#endif
}
// True if we can use dlpi_tls_data. glibc before 2.25 may leave NULL (BZ
// #19826) so dlpi_tls_data cannot be used.
//
// musl before 1.2.3 and FreeBSD as of 12.2 incorrectly set dlpi_tls_data to
// the TLS initialization image
// https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254774
__attribute__((unused)) static int g_use_dlpi_tls_data;
#if SANITIZER_GLIBC && !SANITIZER_GO
__attribute__((unused)) static size_t g_tls_size;
void InitTlsSize() {
int major, minor, patch;
g_use_dlpi_tls_data =
GetLibcVersion(&major, &minor, &patch) && major == 2 && minor >= 25;
#if defined(__aarch64__) || defined(__x86_64__) || defined(__powerpc64__)
void *get_tls_static_info = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
size_t tls_align;
((void (*)(size_t *, size_t *))get_tls_static_info)(&g_tls_size, &tls_align);
#endif
}
#else
void InitTlsSize() { }
#endif // SANITIZER_GLIBC && !SANITIZER_GO
// On glibc x86_64, ThreadDescriptorSize() needs to be precise due to the usage
// of g_tls_size. On other targets, ThreadDescriptorSize() is only used by lsan
// to get the pointer to thread-specific data keys in the thread control block.
#if (SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS) && \
!SANITIZER_ANDROID && !SANITIZER_GO
// sizeof(struct pthread) from glibc.
static atomic_uintptr_t thread_descriptor_size;
static uptr ThreadDescriptorSizeFallback() {
uptr val = 0;
#if defined(__x86_64__) || defined(__i386__) || defined(__arm__)
int major;
int minor;
int patch;
if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
/* sizeof(struct pthread) values from various glibc versions. */
if (SANITIZER_X32)
val = 1728; // Assume only one particular version for x32.
// For ARM sizeof(struct pthread) changed in Glibc 2.23.
else if (SANITIZER_ARM)
val = minor <= 22 ? 1120 : 1216;
else if (minor <= 3)
val = FIRST_32_SECOND_64(1104, 1696);
else if (minor == 4)
val = FIRST_32_SECOND_64(1120, 1728);
else if (minor == 5)
val = FIRST_32_SECOND_64(1136, 1728);
else if (minor <= 9)
val = FIRST_32_SECOND_64(1136, 1712);
else if (minor == 10)
val = FIRST_32_SECOND_64(1168, 1776);
else if (minor == 11 || (minor == 12 && patch == 1))
val = FIRST_32_SECOND_64(1168, 2288);
else if (minor <= 14)
val = FIRST_32_SECOND_64(1168, 2304);
else if (minor < 32) // Unknown version
val = FIRST_32_SECOND_64(1216, 2304);
else // minor == 32
val = FIRST_32_SECOND_64(1344, 2496);
}
#elif defined(__s390__) || defined(__sparc__)
// The size of a prefix of TCB including pthread::{specific_1stblock,specific}
// suffices. Just return offsetof(struct pthread, specific_used), which hasn't
// changed since 2007-05. Technically this applies to i386/x86_64 as well but
// we call _dl_get_tls_static_info and need the precise size of struct
// pthread.
return FIRST_32_SECOND_64(524, 1552);
#elif defined(__mips__)
// TODO(sagarthakur): add more values as per different glibc versions.
val = FIRST_32_SECOND_64(1152, 1776);
#elif SANITIZER_RISCV64
int major;
int minor;
int patch;
if (GetLibcVersion(&major, &minor, &patch) && major == 2) {
// TODO: consider adding an optional runtime check for an unknown (untested)
// glibc version
if (minor <= 28) // WARNING: the highest tested version is 2.29
val = 1772; // no guarantees for this one
else if (minor <= 31)
val = 1772; // tested against glibc 2.29, 2.31
else
val = 1936; // tested against glibc 2.32
}
#elif defined(__aarch64__)
// The sizeof (struct pthread) is the same from GLIBC 2.17 to 2.22.
val = 1776;
#elif defined(__powerpc64__)
val = 1776; // from glibc.ppc64le 2.20-8.fc21
#endif
return val;
}
uptr ThreadDescriptorSize() {
uptr val = atomic_load_relaxed(&thread_descriptor_size);
if (val)
return val;
// _thread_db_sizeof_pthread is a GLIBC_PRIVATE symbol that is exported in
// glibc 2.34 and later.
if (unsigned *psizeof = static_cast<unsigned *>(
dlsym(RTLD_DEFAULT, "_thread_db_sizeof_pthread")))
val = *psizeof;
if (!val)
val = ThreadDescriptorSizeFallback();
atomic_store_relaxed(&thread_descriptor_size, val);
return val;
}
#if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64
// TlsPreTcbSize includes size of struct pthread_descr and size of tcb
// head structure. It lies before the static tls blocks.
static uptr TlsPreTcbSize() {
#if defined(__mips__)
const uptr kTcbHead = 16; // sizeof (tcbhead_t)
#elif defined(__powerpc64__)
const uptr kTcbHead = 88; // sizeof (tcbhead_t)
#elif SANITIZER_RISCV64
const uptr kTcbHead = 16; // sizeof (tcbhead_t)
#endif
const uptr kTlsAlign = 16;
const uptr kTlsPreTcbSize =
RoundUpTo(ThreadDescriptorSize() + kTcbHead, kTlsAlign);
return kTlsPreTcbSize;
}
#endif
namespace {
struct TlsBlock {
uptr begin, end, align;
size_t tls_modid;
bool operator<(const TlsBlock &rhs) const { return begin < rhs.begin; }
};
} // namespace
#ifdef __s390__
extern "C" uptr __tls_get_offset(void *arg);
static uptr TlsGetOffset(uptr ti_module, uptr ti_offset) {
// The __tls_get_offset ABI requires %r12 to point to GOT and %r2 to be an
// offset of a struct tls_index inside GOT. We don't possess either of the
// two, so violate the letter of the "ELF Handling For Thread-Local
// Storage" document and assume that the implementation just dereferences
// %r2 + %r12.
uptr tls_index[2] = {ti_module, ti_offset};
register uptr r2 asm("2") = 0;
register void *r12 asm("12") = tls_index;
asm("basr %%r14, %[__tls_get_offset]"
: "+r"(r2)
: [__tls_get_offset] "r"(__tls_get_offset), "r"(r12)
: "memory", "cc", "0", "1", "3", "4", "5", "14");
return r2;
}
#else
extern "C" void *__tls_get_addr(size_t *);
#endif
static int CollectStaticTlsBlocks(struct dl_phdr_info *info, size_t size,
void *data) {
if (!info->dlpi_tls_modid)
return 0;
uptr begin = (uptr)info->dlpi_tls_data;
if (!g_use_dlpi_tls_data) {
// Call __tls_get_addr as a fallback. This forces TLS allocation on glibc
// and FreeBSD.
#ifdef __s390__
begin = (uptr)__builtin_thread_pointer() +
TlsGetOffset(info->dlpi_tls_modid, 0);
#else
size_t mod_and_off[2] = {info->dlpi_tls_modid, 0};
begin = (uptr)__tls_get_addr(mod_and_off);
#endif
}
for (unsigned i = 0; i != info->dlpi_phnum; ++i)
if (info->dlpi_phdr[i].p_type == PT_TLS) {
static_cast<InternalMmapVector<TlsBlock> *>(data)->push_back(
TlsBlock{begin, begin + info->dlpi_phdr[i].p_memsz,
info->dlpi_phdr[i].p_align, info->dlpi_tls_modid});
break;
}
return 0;
}
__attribute__((unused)) static void GetStaticTlsBoundary(uptr *addr, uptr *size,
uptr *align) {
InternalMmapVector<TlsBlock> ranges;
dl_iterate_phdr(CollectStaticTlsBlocks, &ranges);
uptr len = ranges.size();
Sort(ranges.begin(), len);
// Find the range with tls_modid=1. For glibc, because libc.so uses PT_TLS,
// this module is guaranteed to exist and is one of the initially loaded
// modules.
uptr one = 0;
while (one != len && ranges[one].tls_modid != 1) ++one;
if (one == len) {
// This may happen with musl if no module uses PT_TLS.
*addr = 0;
*size = 0;
*align = 1;
return;
}
// Find the maximum consecutive ranges. We consider two modules consecutive if
// the gap is smaller than the alignment. The dynamic loader places static TLS
// blocks this way not to waste space.
uptr l = one;
*align = ranges[l].align;
while (l != 0 && ranges[l].begin < ranges[l - 1].end + ranges[l - 1].align)
*align = Max(*align, ranges[--l].align);
uptr r = one + 1;
while (r != len && ranges[r].begin < ranges[r - 1].end + ranges[r - 1].align)
*align = Max(*align, ranges[r++].align);
*addr = ranges[l].begin;
*size = ranges[r - 1].end - ranges[l].begin;
}
#endif // (x86_64 || i386 || mips || ...) && (SANITIZER_FREEBSD ||
// SANITIZER_LINUX) && !SANITIZER_ANDROID && !SANITIZER_GO
#if SANITIZER_NETBSD
static struct tls_tcb * ThreadSelfTlsTcb() {
struct tls_tcb *tcb = nullptr;
#ifdef __HAVE___LWP_GETTCB_FAST
tcb = (struct tls_tcb *)__lwp_gettcb_fast();
#elif defined(__HAVE___LWP_GETPRIVATE_FAST)
tcb = (struct tls_tcb *)__lwp_getprivate_fast();
#endif
return tcb;
}
uptr ThreadSelf() {
return (uptr)ThreadSelfTlsTcb()->tcb_pthread;
}
int GetSizeFromHdr(struct dl_phdr_info *info, size_t size, void *data) {
const Elf_Phdr *hdr = info->dlpi_phdr;
const Elf_Phdr *last_hdr = hdr + info->dlpi_phnum;
for (; hdr != last_hdr; ++hdr) {
if (hdr->p_type == PT_TLS && info->dlpi_tls_modid == 1) {
*(uptr*)data = hdr->p_memsz;
break;
}
}
return 0;
}
#endif // SANITIZER_NETBSD
#if SANITIZER_ANDROID
// Bionic provides this API since S.
extern "C" SANITIZER_WEAK_ATTRIBUTE void __libc_get_static_tls_bounds(void **,
void **);
#endif
#if !SANITIZER_GO
static void GetTls(uptr *addr, uptr *size) {
#if SANITIZER_ANDROID
if (&__libc_get_static_tls_bounds) {
void *start_addr;
void *end_addr;
__libc_get_static_tls_bounds(&start_addr, &end_addr);
*addr = reinterpret_cast<uptr>(start_addr);
*size =
reinterpret_cast<uptr>(end_addr) - reinterpret_cast<uptr>(start_addr);
} else {
*addr = 0;
*size = 0;
}
#elif SANITIZER_GLIBC && defined(__x86_64__)
// For aarch64 and x86-64, use an O(1) approach which requires relatively
// precise ThreadDescriptorSize. g_tls_size was initialized in InitTlsSize.
asm("mov %%fs:16,%0" : "=r"(*addr));
*size = g_tls_size;
*addr -= *size;
*addr += ThreadDescriptorSize();
#elif SANITIZER_GLIBC && defined(__aarch64__)
*addr = reinterpret_cast<uptr>(__builtin_thread_pointer()) -
ThreadDescriptorSize();
*size = g_tls_size + ThreadDescriptorSize();
#elif SANITIZER_GLIBC && defined(__powerpc64__)
// Workaround for glibc<2.25(?). 2.27 is known to not need this.
uptr tp;
asm("addi %0,13,-0x7000" : "=r"(tp));
const uptr pre_tcb_size = TlsPreTcbSize();
*addr = tp - pre_tcb_size;
*size = g_tls_size + pre_tcb_size;
#elif SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_SOLARIS
uptr align;
GetStaticTlsBoundary(addr, size, &align);
#if defined(__x86_64__) || defined(__i386__) || defined(__s390__) || \
defined(__sparc__)
if (SANITIZER_GLIBC) {
#if defined(__x86_64__) || defined(__i386__)
align = Max<uptr>(align, 64);
#else
align = Max<uptr>(align, 16);
#endif
}
const uptr tp = RoundUpTo(*addr + *size, align);
// lsan requires the range to additionally cover the static TLS surplus
// (elf/dl-tls.c defines 1664). Otherwise there may be false positives for
// allocations only referenced by tls in dynamically loaded modules.
if (SANITIZER_GLIBC)
*size += 1644;
else if (SANITIZER_FREEBSD)
*size += 128; // RTLD_STATIC_TLS_EXTRA
// Extend the range to include the thread control block. On glibc, lsan needs
// the range to include pthread::{specific_1stblock,specific} so that
// allocations only referenced by pthread_setspecific can be scanned. This may
// underestimate by at most TLS_TCB_ALIGN-1 bytes but it should be fine
// because the number of bytes after pthread::specific is larger.
*addr = tp - RoundUpTo(*size, align);
*size = tp - *addr + ThreadDescriptorSize();
#else
if (SANITIZER_GLIBC)
*size += 1664;
else if (SANITIZER_FREEBSD)
*size += 128; // RTLD_STATIC_TLS_EXTRA
#if defined(__mips__) || defined(__powerpc64__) || SANITIZER_RISCV64
const uptr pre_tcb_size = TlsPreTcbSize();
*addr -= pre_tcb_size;
*size += pre_tcb_size;
#else
// arm and aarch64 reserve two words at TP, so this underestimates the range.
// However, this is sufficient for the purpose of finding the pointers to
// thread-specific data keys.
const uptr tcb_size = ThreadDescriptorSize();
*addr -= tcb_size;
*size += tcb_size;
#endif
#endif
#elif SANITIZER_NETBSD
struct tls_tcb * const tcb = ThreadSelfTlsTcb();
*addr = 0;
*size = 0;
if (tcb != 0) {
// Find size (p_memsz) of dlpi_tls_modid 1 (TLS block of the main program).
// ld.elf_so hardcodes the index 1.
dl_iterate_phdr(GetSizeFromHdr, size);
if (*size != 0) {
// The block has been found and tcb_dtv[1] contains the base address
*addr = (uptr)tcb->tcb_dtv[1];
}
}
#error "Unknown OS"
#endif
}
#endif
#if !SANITIZER_GO
uptr GetTlsSize() {
#if SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD || \
SANITIZER_SOLARIS
uptr addr, size;
GetTls(&addr, &size);
return size;
#else
return 0;
#endif
}
#endif
void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
uptr *tls_addr, uptr *tls_size) {
#if SANITIZER_GO
// Stub implementation for Go.
*stk_addr = *stk_size = *tls_addr = *tls_size = 0;
#else
GetTls(tls_addr, tls_size);
uptr stack_top, stack_bottom;
GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
*stk_addr = stack_bottom;
*stk_size = stack_top - stack_bottom;
if (!main) {
// If stack and tls intersect, make them non-intersecting.
if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
if (*stk_addr + *stk_size < *tls_addr + *tls_size)
*tls_size = *stk_addr + *stk_size - *tls_addr;
*stk_size = *tls_addr - *stk_addr;
}
}
#endif
}
#if !SANITIZER_FREEBSD
typedef ElfW(Phdr) Elf_Phdr;
#elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001 // v9.2
#define Elf_Phdr XElf32_Phdr
#define dl_phdr_info xdl_phdr_info
#define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
#endif // !SANITIZER_FREEBSD
struct DlIteratePhdrData {
InternalMmapVectorNoCtor<LoadedModule> *modules;
bool first;
};
static int AddModuleSegments(const char *module_name, dl_phdr_info *info,
InternalMmapVectorNoCtor<LoadedModule> *modules) {
if (module_name[0] == '\0')
return 0;
LoadedModule cur_module;
cur_module.set(module_name, info->dlpi_addr);
for (int i = 0; i < (int)info->dlpi_phnum; i++) {
const Elf_Phdr *phdr = &info->dlpi_phdr[i];
if (phdr->p_type == PT_LOAD) {
uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
uptr cur_end = cur_beg + phdr->p_memsz;
bool executable = phdr->p_flags & PF_X;
bool writable = phdr->p_flags & PF_W;
cur_module.addAddressRange(cur_beg, cur_end, executable,
writable);
} else if (phdr->p_type == PT_NOTE) {
# ifdef NT_GNU_BUILD_ID
uptr off = 0;
while (off + sizeof(ElfW(Nhdr)) < phdr->p_memsz) {
auto *nhdr = reinterpret_cast<const ElfW(Nhdr) *>(info->dlpi_addr +
phdr->p_vaddr + off);
constexpr auto kGnuNamesz = 4; // "GNU" with NUL-byte.
static_assert(kGnuNamesz % 4 == 0, "kGnuNameSize is aligned to 4.");
if (nhdr->n_type == NT_GNU_BUILD_ID && nhdr->n_namesz == kGnuNamesz) {
if (off + sizeof(ElfW(Nhdr)) + nhdr->n_namesz + nhdr->n_descsz >
phdr->p_memsz) {
// Something is very wrong, bail out instead of reading potentially
// arbitrary memory.
break;
}
const char *name =
reinterpret_cast<const char *>(nhdr) + sizeof(*nhdr);
if (internal_memcmp(name, "GNU", 3) == 0) {
const char *value = reinterpret_cast<const char *>(nhdr) +
sizeof(*nhdr) + kGnuNamesz;
cur_module.setUuid(value, nhdr->n_descsz);
break;
}
}
off += sizeof(*nhdr) + RoundUpTo(nhdr->n_namesz, 4) +
RoundUpTo(nhdr->n_descsz, 4);
}
# endif
}
}
modules->push_back(cur_module);
return 0;
}
static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
DlIteratePhdrData *data = (DlIteratePhdrData *)arg;
if (data->first) {
InternalMmapVector<char> module_name(kMaxPathLength);
data->first = false;
// First module is the binary itself.
ReadBinaryNameCached(module_name.data(), module_name.size());
return AddModuleSegments(module_name.data(), info, data->modules);
}
if (info->dlpi_name) {
InternalScopedString module_name;
module_name.append("%s", info->dlpi_name);
return AddModuleSegments(module_name.data(), info, data->modules);
}
return 0;
}
#if SANITIZER_ANDROID && __ANDROID_API__ < 21
extern "C" __attribute__((weak)) int dl_iterate_phdr(
int (*)(struct dl_phdr_info *, size_t, void *), void *);
#endif
static bool requiresProcmaps() {
#if SANITIZER_ANDROID && __ANDROID_API__ <= 22
// Fall back to /proc/maps if dl_iterate_phdr is unavailable or broken.
// The runtime check allows the same library to work with
// both K and L (and future) Android releases.
return AndroidGetApiLevel() <= ANDROID_LOLLIPOP_MR1;
#else
return false;
#endif
}
static void procmapsInit(InternalMmapVectorNoCtor<LoadedModule> *modules) {
MemoryMappingLayout memory_mapping(/*cache_enabled*/true);
memory_mapping.DumpListOfModules(modules);
}
void ListOfModules::init() {
clearOrInit();
if (requiresProcmaps()) {
procmapsInit(&modules_);
} else {
DlIteratePhdrData data = {&modules_, true};
dl_iterate_phdr(dl_iterate_phdr_cb, &data);
}
}
// When a custom loader is used, dl_iterate_phdr may not contain the full
// list of modules. Allow callers to fall back to using procmaps.
void ListOfModules::fallbackInit() {
if (!requiresProcmaps()) {
clearOrInit();
procmapsInit(&modules_);
} else {
clear();
}
}
// getrusage does not give us the current RSS, only the max RSS.
// Still, this is better than nothing if /proc/self/statm is not available
// for some reason, e.g. due to a sandbox.
static uptr GetRSSFromGetrusage() {
struct rusage usage;
if (getrusage(RUSAGE_SELF, &usage)) // Failed, probably due to a sandbox.
return 0;
return usage.ru_maxrss << 10; // ru_maxrss is in Kb.
}
uptr GetRSS() {
if (!common_flags()->can_use_proc_maps_statm)
return GetRSSFromGetrusage();
fd_t fd = OpenFile("/proc/self/statm", RdOnly);
if (fd == kInvalidFd)
return GetRSSFromGetrusage();
char buf[64];
uptr len = internal_read(fd, buf, sizeof(buf) - 1);
internal_close(fd);
if ((sptr)len <= 0)
return 0;
buf[len] = 0;
// The format of the file is:
// 1084 89 69 11 0 79 0
// We need the second number which is RSS in pages.
char *pos = buf;
// Skip the first number.
while (*pos >= '0' && *pos <= '9')
pos++;
// Skip whitespaces.
while (!(*pos >= '0' && *pos <= '9') && *pos != 0)
pos++;
// Read the number.
uptr rss = 0;
while (*pos >= '0' && *pos <= '9')
rss = rss * 10 + *pos++ - '0';
return rss * GetPageSizeCached();
}
// sysconf(_SC_NPROCESSORS_{CONF,ONLN}) cannot be used on most platforms as
// they allocate memory.
u32 GetNumberOfCPUs() {
#if SANITIZER_FREEBSD || SANITIZER_NETBSD
u32 ncpu;
int req[2];
uptr len = sizeof(ncpu);
req[0] = CTL_HW;
req[1] = HW_NCPU;
CHECK_EQ(internal_sysctl(req, 2, &ncpu, &len, NULL, 0), 0);
return ncpu;
#elif SANITIZER_ANDROID && !defined(CPU_COUNT) && !defined(__aarch64__)
// Fall back to /sys/devices/system/cpu on Android when cpu_set_t doesn't
// exist in sched.h. That is the case for toolchains generated with older
// NDKs.
// This code doesn't work on AArch64 because internal_getdents makes use of
// the 64bit getdents syscall, but cpu_set_t seems to always exist on AArch64.
uptr fd = internal_open("/sys/devices/system/cpu", O_RDONLY | O_DIRECTORY);
if (internal_iserror(fd))
return 0;
InternalMmapVector<u8> buffer(4096);
uptr bytes_read = buffer.size();
uptr n_cpus = 0;
u8 *d_type;
struct linux_dirent *entry = (struct linux_dirent *)&buffer[bytes_read];
while (true) {
if ((u8 *)entry >= &buffer[bytes_read]) {
bytes_read = internal_getdents(fd, (struct linux_dirent *)buffer.data(),
buffer.size());
if (internal_iserror(bytes_read) || !bytes_read)
break;
entry = (struct linux_dirent *)buffer.data();
}
d_type = (u8 *)entry + entry->d_reclen - 1;
if (d_type >= &buffer[bytes_read] ||
(u8 *)&entry->d_name[3] >= &buffer[bytes_read])
break;
if (entry->d_ino != 0 && *d_type == DT_DIR) {
if (entry->d_name[0] == 'c' && entry->d_name[1] == 'p' &&
entry->d_name[2] == 'u' &&
entry->d_name[3] >= '0' && entry->d_name[3] <= '9')
n_cpus++;
}
entry = (struct linux_dirent *)(((u8 *)entry) + entry->d_reclen);
}
internal_close(fd);
return n_cpus;
#elif SANITIZER_SOLARIS
return sysconf(_SC_NPROCESSORS_ONLN);
#else
#if defined(CPU_COUNT)
cpu_set_t CPUs;
CHECK_EQ(sched_getaffinity(0, sizeof(cpu_set_t), &CPUs), 0);
return CPU_COUNT(&CPUs);
#else
return 1;
#endif
#endif
}
#if SANITIZER_LINUX
#if SANITIZER_ANDROID
static atomic_uint8_t android_log_initialized;
void AndroidLogInit() {
openlog(GetProcessName(), 0, LOG_USER);
atomic_store(&android_log_initialized, 1, memory_order_release);
}
static bool ShouldLogAfterPrintf() {
return atomic_load(&android_log_initialized, memory_order_acquire);
}
extern "C" SANITIZER_WEAK_ATTRIBUTE
int async_safe_write_log(int pri, const char* tag, const char* msg);
extern "C" SANITIZER_WEAK_ATTRIBUTE
int __android_log_write(int prio, const char* tag, const char* msg);
// ANDROID_LOG_INFO is 4, but can't be resolved at runtime.
#define SANITIZER_ANDROID_LOG_INFO 4
// async_safe_write_log is a new public version of __libc_write_log that is
// used behind syslog. It is preferable to syslog as it will not do any dynamic
// memory allocation or formatting.
// If the function is not available, syslog is preferred for L+ (it was broken
// pre-L) as __android_log_write triggers a racey behavior with the strncpy
// interceptor. Fallback to __android_log_write pre-L.
void WriteOneLineToSyslog(const char *s) {
if (&async_safe_write_log) {
async_safe_write_log(SANITIZER_ANDROID_LOG_INFO, GetProcessName(), s);
} else if (AndroidGetApiLevel() > ANDROID_KITKAT) {
syslog(LOG_INFO, "%s", s);
} else {
CHECK(&__android_log_write);
__android_log_write(SANITIZER_ANDROID_LOG_INFO, nullptr, s);
}
}
extern "C" SANITIZER_WEAK_ATTRIBUTE
void android_set_abort_message(const char *);
void SetAbortMessage(const char *str) {
if (&android_set_abort_message)
android_set_abort_message(str);
}
#else
void AndroidLogInit() {}
static bool ShouldLogAfterPrintf() { return true; }
void WriteOneLineToSyslog(const char *s) { syslog(LOG_INFO, "%s", s); }
void SetAbortMessage(const char *str) {}
#endif // SANITIZER_ANDROID
void LogMessageOnPrintf(const char *str) {
if (common_flags()->log_to_syslog && ShouldLogAfterPrintf())
WriteToSyslog(str);
}
#endif // SANITIZER_LINUX
#if SANITIZER_GLIBC && !SANITIZER_GO
// glibc crashes when using clock_gettime from a preinit_array function as the
// vDSO function pointers haven't been initialized yet. __progname is
// initialized after the vDSO function pointers, so if it exists, is not null
// and is not empty, we can use clock_gettime.
extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname;
inline bool CanUseVDSO() { return &__progname && __progname && *__progname; }
// MonotonicNanoTime is a timing function that can leverage the vDSO by calling
// clock_gettime. real_clock_gettime only exists if clock_gettime is
// intercepted, so define it weakly and use it if available.
extern "C" SANITIZER_WEAK_ATTRIBUTE
int real_clock_gettime(u32 clk_id, void *tp);
u64 MonotonicNanoTime() {
timespec ts;
if (CanUseVDSO()) {
if (&real_clock_gettime)
real_clock_gettime(CLOCK_MONOTONIC, &ts);
else
clock_gettime(CLOCK_MONOTONIC, &ts);
} else {
internal_clock_gettime(CLOCK_MONOTONIC, &ts);
}
return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
}
#else
// Non-glibc & Go always use the regular function.
u64 MonotonicNanoTime() {
timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec;
}
#endif // SANITIZER_GLIBC && !SANITIZER_GO
void ReExec() {
const char *pathname = "/proc/self/exe";
#if SANITIZER_NETBSD
static const int name[] = {
CTL_KERN,
KERN_PROC_ARGS,
-1,
KERN_PROC_PATHNAME,
};
char path[400];
uptr len;
len = sizeof(path);
if (internal_sysctl(name, ARRAY_SIZE(name), path, &len, NULL, 0) != -1)
pathname = path;
#elif SANITIZER_SOLARIS
pathname = getexecname();
CHECK_NE(pathname, NULL);
#elif SANITIZER_USE_GETAUXVAL
// Calling execve with /proc/self/exe sets that as $EXEC_ORIGIN. Binaries that
// rely on that will fail to load shared libraries. Query AT_EXECFN instead.
pathname = reinterpret_cast<const char *>(getauxval(AT_EXECFN));
#endif
uptr rv = internal_execve(pathname, GetArgv(), GetEnviron());
int rverrno;
CHECK_EQ(internal_iserror(rv, &rverrno), true);
Printf("execve failed, errno %d\n", rverrno);
Die();
}
void UnmapFromTo(uptr from, uptr to) {
if (to == from)
return;
CHECK(to >= from);
uptr res = internal_munmap(reinterpret_cast<void *>(from), to - from);
if (UNLIKELY(internal_iserror(res))) {
Report("ERROR: %s failed to unmap 0x%zx (%zd) bytes at address %p\n",
SanitizerToolName, to - from, to - from, (void *)from);
CHECK("unable to unmap" && 0);
}
}
uptr MapDynamicShadow(uptr shadow_size_bytes, uptr shadow_scale,
uptr min_shadow_base_alignment,
UNUSED uptr &high_mem_end) {
const uptr granularity = GetMmapGranularity();
const uptr alignment =
Max<uptr>(granularity << shadow_scale, 1ULL << min_shadow_base_alignment);
const uptr left_padding =
Max<uptr>(granularity, 1ULL << min_shadow_base_alignment);
const uptr shadow_size = RoundUpTo(shadow_size_bytes, granularity);
const uptr map_size = shadow_size + left_padding + alignment;
const uptr map_start = (uptr)MmapNoAccess(map_size);
CHECK_NE(map_start, ~(uptr)0);
const uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
UnmapFromTo(map_start, shadow_start - left_padding);
UnmapFromTo(shadow_start + shadow_size, map_start + map_size);
return shadow_start;
}
static uptr MmapSharedNoReserve(uptr addr, uptr size) {
return internal_mmap(
reinterpret_cast<void *>(addr), size, PROT_READ | PROT_WRITE,
MAP_FIXED | MAP_SHARED | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
}
static uptr MremapCreateAlias(uptr base_addr, uptr alias_addr,
uptr alias_size) {
#if SANITIZER_LINUX
return internal_mremap(reinterpret_cast<void *>(base_addr), 0, alias_size,
MREMAP_MAYMOVE | MREMAP_FIXED,
reinterpret_cast<void *>(alias_addr));
#else
CHECK(false && "mremap is not supported outside of Linux");
return 0;
#endif
}
static void CreateAliases(uptr start_addr, uptr alias_size, uptr num_aliases) {
uptr total_size = alias_size * num_aliases;
uptr mapped = MmapSharedNoReserve(start_addr, total_size);
CHECK_EQ(mapped, start_addr);
for (uptr i = 1; i < num_aliases; ++i) {
uptr alias_addr = start_addr + i * alias_size;
CHECK_EQ(MremapCreateAlias(start_addr, alias_addr, alias_size), alias_addr);
}
}
uptr MapDynamicShadowAndAliases(uptr shadow_size, uptr alias_size,
uptr num_aliases, uptr ring_buffer_size) {
CHECK_EQ(alias_size & (alias_size - 1), 0);
CHECK_EQ(num_aliases & (num_aliases - 1), 0);
CHECK_EQ(ring_buffer_size & (ring_buffer_size - 1), 0);
const uptr granularity = GetMmapGranularity();
shadow_size = RoundUpTo(shadow_size, granularity);
CHECK_EQ(shadow_size & (shadow_size - 1), 0);
const uptr alias_region_size = alias_size * num_aliases;
const uptr alignment =
2 * Max(Max(shadow_size, alias_region_size), ring_buffer_size);
const uptr left_padding = ring_buffer_size;
const uptr right_size = alignment;
const uptr map_size = left_padding + 2 * alignment;
const uptr map_start = reinterpret_cast<uptr>(MmapNoAccess(map_size));
CHECK_NE(map_start, static_cast<uptr>(-1));
const uptr right_start = RoundUpTo(map_start + left_padding, alignment);
UnmapFromTo(map_start, right_start - left_padding);
UnmapFromTo(right_start + right_size, map_start + map_size);
CreateAliases(right_start + right_size / 2, alias_size, num_aliases);
return right_start;
}
void InitializePlatformCommonFlags(CommonFlags *cf) {
#if SANITIZER_ANDROID
if (&__libc_get_static_tls_bounds == nullptr)
cf->detect_leaks = false;
#endif
}
} // namespace __sanitizer
#endif
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