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llvm-project/compiler-rt/lib/sanitizer_common/sanitizer_linux_libcdep.cc

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//===-- sanitizer_linux_libcdep.cc ----------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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
#include "sanitizer_common.h"
#include "sanitizer_flags.h"
#include "sanitizer_linux.h"
#include "sanitizer_placement_new.h"
#include "sanitizer_procmaps.h"
#include "sanitizer_stacktrace.h"
#include "sanitizer_atomic.h"
#include "sanitizer_symbolizer.h"
#include <dlfcn.h>
#include <pthread.h>
#include <signal.h>
#include <sys/resource.h>
#if SANITIZER_FREEBSD
#define _GNU_SOURCE // to declare _Unwind_Backtrace() from <unwind.h>
#endif
#include <unwind.h>
#if SANITIZER_FREEBSD
#include <pthread_np.h>
#define pthread_getattr_np pthread_attr_get_np
#endif
#if SANITIZER_LINUX
#include <sys/prctl.h>
#endif
#if !SANITIZER_ANDROID
#include <elf.h>
#include <link.h>
#include <unistd.h>
#endif
namespace __sanitizer {
// This function is defined elsewhere if we intercepted pthread_attr_getstack.
extern "C" {
SANITIZER_WEAK_ATTRIBUTE int
real_pthread_attr_getstack(void *attr, void **addr, size_t *size);
} // extern "C"
static int my_pthread_attr_getstack(void *attr, void **addr, size_t *size) {
if (real_pthread_attr_getstack)
return real_pthread_attr_getstack((pthread_attr_t *)attr, addr, size);
return pthread_attr_getstack((pthread_attr_t *)attr, addr, size);
}
SANITIZER_WEAK_ATTRIBUTE int
real_sigaction(int signum, const void *act, void *oldact);
int internal_sigaction(int signum, const void *act, void *oldact) {
if (real_sigaction)
return real_sigaction(signum, act, oldact);
return sigaction(signum, (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);
uptr start, end, offset;
uptr prev_end = 0;
while (proc_maps.Next(&start, &end, &offset, 0, 0, /* protection */0)) {
if ((uptr)&rl < end)
break;
prev_end = end;
}
CHECK((uptr)&rl >= start && (uptr)&rl < end);
// Get stacksize from rlimit, but clip it so that it does not overlap
// with other mappings.
uptr stacksize = rl.rlim_cur;
if (stacksize > end - prev_end)
stacksize = 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 = end;
*stack_bottom = end - stacksize;
return;
}
pthread_attr_t attr;
pthread_attr_init(&attr);
CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
uptr stacksize = 0;
void *stackaddr = 0;
my_pthread_attr_getstack(&attr, &stackaddr, (size_t*)&stacksize);
pthread_attr_destroy(&attr);
CHECK_LE(stacksize, kMaxThreadStackSize); // Sanity check.
*stack_top = (uptr)stackaddr + stacksize;
*stack_bottom = (uptr)stackaddr;
}
bool SetEnv(const char *name, const char *value) {
void *f = dlsym(RTLD_NEXT, "setenv");
if (f == 0)
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 IndirectExternCall(setenv_f)(name, value, 1) == 0;
}
bool SanitizerSetThreadName(const char *name) {
#ifdef PR_SET_NAME
return 0 == prctl(PR_SET_NAME, (unsigned long)name, 0, 0, 0); // NOLINT
#else
return false;
#endif
}
bool SanitizerGetThreadName(char *name, int max_len) {
#ifdef PR_GET_NAME
char buff[17];
if (prctl(PR_GET_NAME, (unsigned long)buff, 0, 0, 0)) // NOLINT
return false;
internal_strncpy(name, buff, max_len);
name[max_len] = 0;
return true;
#else
return false;
#endif
}
//------------------------- SlowUnwindStack -----------------------------------
typedef struct {
uptr absolute_pc;
uptr stack_top;
uptr stack_size;
} backtrace_frame_t;
extern "C" {
typedef void *(*acquire_my_map_info_list_func)();
typedef void (*release_my_map_info_list_func)(void *map);
typedef sptr (*unwind_backtrace_signal_arch_func)(
void *siginfo, void *sigcontext, void *map_info_list,
backtrace_frame_t *backtrace, uptr ignore_depth, uptr max_depth);
acquire_my_map_info_list_func acquire_my_map_info_list;
release_my_map_info_list_func release_my_map_info_list;
unwind_backtrace_signal_arch_func unwind_backtrace_signal_arch;
} // extern "C"
#if SANITIZER_ANDROID
void SanitizerInitializeUnwinder() {
void *p = dlopen("libcorkscrew.so", RTLD_LAZY);
if (!p) {
VReport(1,
"Failed to open libcorkscrew.so. You may see broken stack traces "
"in SEGV reports.");
return;
}
acquire_my_map_info_list =
(acquire_my_map_info_list_func)(uptr)dlsym(p, "acquire_my_map_info_list");
release_my_map_info_list =
(release_my_map_info_list_func)(uptr)dlsym(p, "release_my_map_info_list");
unwind_backtrace_signal_arch = (unwind_backtrace_signal_arch_func)(uptr)dlsym(
p, "unwind_backtrace_signal_arch");
if (!acquire_my_map_info_list || !release_my_map_info_list ||
!unwind_backtrace_signal_arch) {
VReport(1,
"Failed to find one of the required symbols in libcorkscrew.so. "
"You may see broken stack traces in SEGV reports.");
acquire_my_map_info_list = NULL;
unwind_backtrace_signal_arch = NULL;
release_my_map_info_list = NULL;
}
}
#endif
#ifdef __arm__
#define UNWIND_STOP _URC_END_OF_STACK
#define UNWIND_CONTINUE _URC_NO_REASON
#else
#define UNWIND_STOP _URC_NORMAL_STOP
#define UNWIND_CONTINUE _URC_NO_REASON
#endif
uptr Unwind_GetIP(struct _Unwind_Context *ctx) {
#ifdef __arm__
uptr val;
_Unwind_VRS_Result res = _Unwind_VRS_Get(ctx, _UVRSC_CORE,
15 /* r15 = PC */, _UVRSD_UINT32, &val);
CHECK(res == _UVRSR_OK && "_Unwind_VRS_Get failed");
// Clear the Thumb bit.
return val & ~(uptr)1;
#else
return _Unwind_GetIP(ctx);
#endif
}
struct UnwindTraceArg {
StackTrace *stack;
uptr max_depth;
};
_Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx, void *param) {
UnwindTraceArg *arg = (UnwindTraceArg*)param;
CHECK_LT(arg->stack->size, arg->max_depth);
uptr pc = Unwind_GetIP(ctx);
arg->stack->trace[arg->stack->size++] = pc;
if (arg->stack->size == arg->max_depth) return UNWIND_STOP;
return UNWIND_CONTINUE;
}
void StackTrace::SlowUnwindStack(uptr pc, uptr max_depth) {
CHECK_GE(max_depth, 2);
size = 0;
UnwindTraceArg arg = {this, Min(max_depth + 1, kStackTraceMax)};
_Unwind_Backtrace(Unwind_Trace, &arg);
// We need to pop a few frames so that pc is on top.
uptr to_pop = LocatePcInTrace(pc);
// trace[0] belongs to the current function so we always pop it.
if (to_pop == 0)
to_pop = 1;
PopStackFrames(to_pop);
trace[0] = pc;
}
void StackTrace::SlowUnwindStackWithContext(uptr pc, void *context,
uptr max_depth) {
CHECK_GE(max_depth, 2);
if (!unwind_backtrace_signal_arch) {
SlowUnwindStack(pc, max_depth);
return;
}
void *map = acquire_my_map_info_list();
CHECK(map);
InternalScopedBuffer<backtrace_frame_t> frames(kStackTraceMax);
// siginfo argument appears to be unused.
sptr res = unwind_backtrace_signal_arch(/* siginfo */ NULL, context, map,
frames.data(),
/* ignore_depth */ 0, max_depth);
release_my_map_info_list(map);
if (res < 0) return;
CHECK_LE((uptr)res, kStackTraceMax);
size = 0;
// +2 compensate for libcorkscrew unwinder returning addresses of call
// instructions instead of raw return addresses.
for (sptr i = 0; i < res; ++i)
trace[size++] = frames[i].absolute_pc + 2;
}
#if !SANITIZER_FREEBSD
static uptr g_tls_size;
#endif
#ifdef __i386__
# define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
#else
# define DL_INTERNAL_FUNCTION
#endif
void InitTlsSize() {
#if !SANITIZER_FREEBSD && !SANITIZER_ANDROID
typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
get_tls_func get_tls;
void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
CHECK_EQ(sizeof(get_tls), sizeof(get_tls_static_info_ptr));
internal_memcpy(&get_tls, &get_tls_static_info_ptr,
sizeof(get_tls_static_info_ptr));
CHECK_NE(get_tls, 0);
size_t tls_size = 0;
size_t tls_align = 0;
IndirectExternCall(get_tls)(&tls_size, &tls_align);
g_tls_size = tls_size;
#endif // !SANITIZER_FREEBSD && !SANITIZER_ANDROID
}
#if (defined(__x86_64__) || defined(__i386__)) && SANITIZER_LINUX
// sizeof(struct thread) from glibc.
static atomic_uintptr_t kThreadDescriptorSize;
uptr ThreadDescriptorSize() {
char buf[64];
uptr val = atomic_load(&kThreadDescriptorSize, memory_order_relaxed);
if (val)
return val;
#ifdef _CS_GNU_LIBC_VERSION
uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
if (len < sizeof(buf) && internal_strncmp(buf, "glibc 2.", 8) == 0) {
char *end;
int minor = internal_simple_strtoll(buf + 8, &end, 10);
if (end != buf + 8 && (*end == '\0' || *end == '.')) {
/* sizeof(struct thread) values from various glibc versions. */
if (SANITIZER_X32)
val = 1728; // Assume only one particular version for x32.
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 <= 12)
val = FIRST_32_SECOND_64(1168, 2288);
else
val = FIRST_32_SECOND_64(1216, 2304);
}
if (val)
atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
return val;
}
#endif
return 0;
}
// The offset at which pointer to self is located in the thread descriptor.
const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
uptr ThreadSelfOffset() {
return kThreadSelfOffset;
}
uptr ThreadSelf() {
uptr descr_addr;
# if defined(__i386__)
asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
# elif defined(__x86_64__)
asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
# else
# error "unsupported CPU arch"
# endif
return descr_addr;
}
#endif // (defined(__x86_64__) || defined(__i386__)) && SANITIZER_LINUX
#if SANITIZER_FREEBSD
static void **ThreadSelfSegbase() {
void **segbase = 0;
# if defined(__i386__)
// sysarch(I386_GET_GSBASE, segbase);
__asm __volatile("mov %%gs:0, %0" : "=r" (segbase));
# elif defined(__x86_64__)
// sysarch(AMD64_GET_FSBASE, segbase);
__asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
# else
# error "unsupported CPU arch for FreeBSD platform"
# endif
return segbase;
}
uptr ThreadSelf() {
return (uptr)ThreadSelfSegbase()[2];
}
#endif // SANITIZER_FREEBSD
static void GetTls(uptr *addr, uptr *size) {
#if SANITIZER_LINUX
# if defined(__x86_64__) || defined(__i386__)
*addr = ThreadSelf();
*size = GetTlsSize();
*addr -= *size;
*addr += ThreadDescriptorSize();
# else
*addr = 0;
*size = 0;
# endif
#elif SANITIZER_FREEBSD
void** segbase = ThreadSelfSegbase();
*addr = 0;
*size = 0;
if (segbase != 0) {
// tcbalign = 16
// tls_size = round(tls_static_space, tcbalign);
// dtv = segbase[1];
// dtv[2] = segbase - tls_static_space;
void **dtv = (void**) segbase[1];
*addr = (uptr) dtv[2];
*size = (*addr == 0) ? 0 : ((uptr) segbase[0] - (uptr) dtv[2]);
}
#else
# error "Unknown OS"
#endif
}
uptr GetTlsSize() {
#if SANITIZER_FREEBSD
uptr addr, size;
GetTls(&addr, &size);
return size;
#else
return g_tls_size;
#endif
}
void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
uptr *tls_addr, uptr *tls_size) {
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) {
CHECK_GT(*tls_addr + *tls_size, *stk_addr);
CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
*stk_size -= *tls_size;
*tls_addr = *stk_addr + *stk_size;
}
}
}
void AdjustStackSize(void *attr_) {
pthread_attr_t *attr = (pthread_attr_t *)attr_;
uptr stackaddr = 0;
size_t stacksize = 0;
my_pthread_attr_getstack(attr, (void**)&stackaddr, &stacksize);
// GLibC will return (0 - stacksize) as the stack address in the case when
// stacksize is set, but stackaddr is not.
bool stack_set = (stackaddr != 0) && (stackaddr + stacksize != 0);
// We place a lot of tool data into TLS, account for that.
const uptr minstacksize = GetTlsSize() + 128*1024;
if (stacksize < minstacksize) {
if (!stack_set) {
if (stacksize != 0) {
VPrintf(1, "Sanitizer: increasing stacksize %zu->%zu\n", stacksize,
minstacksize);
pthread_attr_setstacksize(attr, minstacksize);
}
} else {
Printf("Sanitizer: pre-allocated stack size is insufficient: "
"%zu < %zu\n", stacksize, minstacksize);
Printf("Sanitizer: pthread_create is likely to fail.\n");
}
}
}
#if SANITIZER_ANDROID
uptr GetListOfModules(LoadedModule *modules, uptr max_modules,
string_predicate_t filter) {
MemoryMappingLayout memory_mapping(false);
return memory_mapping.DumpListOfModules(modules, max_modules, filter);
}
#else // SANITIZER_ANDROID
# if !SANITIZER_FREEBSD
typedef ElfW(Phdr) Elf_Phdr;
# endif
struct DlIteratePhdrData {
LoadedModule *modules;
uptr current_n;
bool first;
uptr max_n;
string_predicate_t filter;
};
static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
if (data->current_n == data->max_n)
return 0;
InternalScopedBuffer<char> module_name(kMaxPathLength);
module_name.data()[0] = '\0';
if (data->first) {
data->first = false;
// First module is the binary itself.
ReadBinaryName(module_name.data(), module_name.size());
} else if (info->dlpi_name) {
internal_strncpy(module_name.data(), info->dlpi_name, module_name.size());
}
if (module_name.data()[0] == '\0')
return 0;
if (data->filter && !data->filter(module_name.data()))
return 0;
void *mem = &data->modules[data->current_n];
LoadedModule *cur_module = new(mem) LoadedModule(module_name.data(),
info->dlpi_addr);
data->current_n++;
for (int i = 0; i < 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;
cur_module->addAddressRange(cur_beg, cur_end);
}
}
return 0;
}
uptr GetListOfModules(LoadedModule *modules, uptr max_modules,
string_predicate_t filter) {
CHECK(modules);
DlIteratePhdrData data = {modules, 0, true, max_modules, filter};
dl_iterate_phdr(dl_iterate_phdr_cb, &data);
return data.current_n;
}
#endif // SANITIZER_ANDROID
uptr indirect_call_wrapper;
void SetIndirectCallWrapper(uptr wrapper) {
CHECK(!indirect_call_wrapper);
CHECK(wrapper);
indirect_call_wrapper = wrapper;
}
void PrepareForSandboxing(__sanitizer_sandbox_arguments *args) {
// Some kinds of sandboxes may forbid filesystem access, so we won't be able
// to read the file mappings from /proc/self/maps. Luckily, neither the
// process will be able to load additional libraries, so it's fine to use the
// cached mappings.
MemoryMappingLayout::CacheMemoryMappings();
// Same for /proc/self/exe in the symbolizer.
#if !SANITIZER_GO
if (Symbolizer *sym = Symbolizer::GetOrNull())
sym->PrepareForSandboxing();
CovPrepareForSandboxing(args);
#endif
}
} // namespace __sanitizer
#endif // SANITIZER_FREEBSD || SANITIZER_LINUX
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