"struct sigaction",
"union sigval",
"siginfo_t",
+ "stack_t",
"pid_t",
];
}
libc.src.signal.raise
libc.src.signal.kill
libc.src.signal.sigaction
+ libc.src.signal.sigaltstack
libc.src.signal.sigdelset
libc.src.signal.sigaddset
libc.src.signal.sigemptyset
.llvm-libc-macros.signal_macros
.llvm-libc-types.struct_sigaction
.llvm-libc-types.__sighandler_t
+ .llvm-libc-types.stack_t
.llvm-libc-types.sigset_t
.llvm-libc-types.pid_t
)
#define SA_SIGINFO 0x00000004
#define SA_RESTART 0x10000000
#define SA_RESTORER 0x04000000
+#define SA_ONSTACK 0x08000000
+
+// Signal stack flags
+#define SS_ONSTACK 0x1
+#define SS_DISABLE 0x2
+
+#ifdef __x86_64__
+#define MINSIGSTKSZ 2048
+#define SIGSTKSZ 8192
+#elif defined(__aarch64__)
+#define MINSIGSTKSZ 5120
+#define SIGSTKSZ 16384
+#else
+#error "Signal stack sizes not defined for your platform."
+#endif
#define SIG_DFL ((__sighandler_t)0)
#define SIG_IGN ((__sighandler_t)1)
add_header(pthread_once_t HDR pthread_once_t.h DEPENDS .__futex_word)
add_header(rlim_t HDR rlim_t.h)
add_header(time_t HDR time_t.h)
+add_header(stack_t HDR stack_t.h)
add_header(suseconds_t HDR suseconds_t.h)
add_header(struct_timeval HDR struct_timeval.h DEPENDS .suseconds_t .time_t)
add_header(struct_rlimit HDR struct_rlimit.h DEPENDS .rlim_t)
--- /dev/null
+//===-- Definition of stack_t type ----------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __LLVM_LIBC_TYPES_STACK_T_H__
+#define __LLVM_LIBC_TYPES_STACK_T_H__
+
+#include <llvm-libc-types/size_t.h>
+
+typedef struct {
+ // The order of the fields declared here should match the kernel definition
+ // of stack_t in order for the SYS_sigaltstack syscall to work correctly.
+ void *ss_sp;
+ int ss_flags;
+ size_t ss_size;
+} stack_t;
+
+#endif // __LLVM_LIBC_TYPES_STACK_T_H__
def ConstStructTermiosPtr : ConstType<StructTermiosPtr>;
def TcFlagT : NamedType<"tcflag_t">;
+def StackT : NamedType<"stack_t">;
+def StackTPtr : PtrType<StackT>;
+def RestrictedStackTPtr : RestrictedPtrType<StackT>;
+def ConstRestrictedStackTPtr : ConstType<RestrictedStackTPtr>;
+
def POSIX : StandardSpec<"POSIX"> {
PtrType CharPtr = PtrType<CharType>;
RestrictedPtrType RestrictedCharPtr = RestrictedPtrType<CharType>;
[
SigInfoType,
SigSetType,
+ StackT,
StructSigaction,
UnionSigVal,
PidT,
ArgSpec<RestrictedStructSigactionPtr>]
>,
FunctionSpec<
+ "sigaltstack",
+ RetValSpec<IntType>,
+ [ArgSpec<ConstRestrictedStackTPtr>, ArgSpec<RestrictedStackTPtr>]
+ >,
+ FunctionSpec<
"sigdelset",
RetValSpec<IntType>,
[ArgSpec<SigSetPtrType>,
)
add_entrypoint_object(
+ sigaltstack
+ ALIAS
+ DEPENDS
+ .${LIBC_TARGET_OS}.sigaltstack
+)
+
+add_entrypoint_object(
sigprocmask
ALIAS
DEPENDS
)
add_entrypoint_object(
+ sigaltstack
+ SRCS
+ sigaltstack.cpp
+ HDRS
+ ../sigaltstack.h
+ DEPENDS
+ libc.include.signal
+ libc.include.sys_syscall
+ libc.src.__support.OSUtil.osutil
+ libc.src.errno.errno
+)
+
+add_entrypoint_object(
sigprocmask
SRCS
sigprocmask.cpp
--- /dev/null
+//===-- Linux implementation of sigaltstack -------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/signal/sigaltstack.h"
+#include "src/signal/linux/signal_utils.h"
+
+#include "src/__support/common.h"
+
+#include <errno.h>
+#include <signal.h>
+#include <sys/syscall.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, sigaltstack,
+ (const stack_t *__restrict ss, stack_t *__restrict oss)) {
+ if (ss != nullptr) {
+ unsigned not_ss_disable = ~unsigned(SS_DISABLE);
+ if ((unsigned(ss->ss_flags) & not_ss_disable) != 0) {
+ // Flags cannot have anything other than SS_DISABLE set.
+ // We do the type-casting to unsigned because the |ss_flags|
+ // field of stack_t is of type "int".
+ errno = EINVAL;
+ return -1;
+ }
+ if (ss->ss_size < MINSIGSTKSZ) {
+ errno = ENOMEM;
+ return -1;
+ }
+ }
+
+ int ret = __llvm_libc::syscall_impl(SYS_sigaltstack, ss, oss);
+ if (ret < 0) {
+ errno = -ret;
+ return -1;
+ }
+ return 0;
+}
+
+} // namespace __llvm_libc
--- /dev/null
+//===-- Implementation header for sigaltstack -------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_SIGNAL_SIGALSTACK_H
+#define LLVM_LIBC_SRC_SIGNAL_SIGALSTACK_H
+
+#include <signal.h>
+
+namespace __llvm_libc {
+
+int sigaltstack(const stack_t *__restrict ss, stack_t *__restrict oss);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_SIGNAL_SIGALSTACK_H
libc.src.signal.sigprocmask
libc.test.errno_setter_matcher
)
+
+add_libc_unittest(
+ sigaltstack_test
+ SUITE
+ libc_signal_unittests
+ SRCS
+ sigaltstack_test.cpp
+ DEPENDS
+ libc.include.errno
+ libc.include.signal
+ libc.src.signal.raise
+ libc.src.signal.sigaltstack
+ libc.src.signal.sigaction
+)
--- /dev/null
+//===-- Unittests for sigaltstack -----------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/signal/linux/signal_utils.h"
+#include "src/signal/raise.h"
+#include "src/signal/sigaction.h"
+#include "src/signal/sigaltstack.h"
+
+#include "test/ErrnoSetterMatcher.h"
+#include "utils/UnitTest/Test.h"
+
+#include <errno.h>
+#include <signal.h>
+#include <stdint.h>
+#include <sys/syscall.h>
+
+constexpr int LOCAL_VAR_SIZE = 512;
+constexpr int ALT_STACK_SIZE = SIGSTKSZ + LOCAL_VAR_SIZE * 2;
+static uint8_t alt_stack[ALT_STACK_SIZE];
+
+using __llvm_libc::testing::ErrnoSetterMatcher::Fails;
+using __llvm_libc::testing::ErrnoSetterMatcher::Succeeds;
+
+static bool good_stack;
+static void handler(int) {
+ // Allocate a large stack variable so that it does not get optimized
+ // out or mapped to a register.
+ uint8_t var[LOCAL_VAR_SIZE];
+ for (int i = 0; i < LOCAL_VAR_SIZE; ++i)
+ var[i] = i;
+ // Verify that array is completely on the alt_stack.
+ for (int i = 0; i < LOCAL_VAR_SIZE; ++i) {
+ if (!(uintptr_t(var + i) < uintptr_t(alt_stack + ALT_STACK_SIZE) &&
+ uintptr_t(alt_stack) <= uintptr_t(var + i))) {
+ good_stack = false;
+ return;
+ }
+ }
+ good_stack = true;
+}
+
+TEST(LlvmLibcSignalTest, SigaltstackRunOnAltStack) {
+ struct sigaction action;
+ errno = 0;
+ ASSERT_THAT(__llvm_libc::sigaction(SIGUSR1, nullptr, &action), Succeeds(0));
+ action.sa_handler = handler;
+ // Indicate that the signal should be delivered on an alternate stack.
+ action.sa_flags = SA_ONSTACK;
+ ASSERT_THAT(__llvm_libc::sigaction(SIGUSR1, &action, nullptr), Succeeds(0));
+
+ stack_t ss;
+ ss.ss_sp = alt_stack;
+ ss.ss_size = ALT_STACK_SIZE;
+ ss.ss_flags = 0;
+ // Setup the alternate stack.
+ ASSERT_THAT(__llvm_libc::sigaltstack(&ss, nullptr), Succeeds(0));
+
+ good_stack = false;
+ __llvm_libc::raise(SIGUSR1);
+ EXPECT_TRUE(good_stack);
+}
+
+// This tests for invalid input.
+TEST(LlvmLibcSignalTest, SigaltstackInvalidStack) {
+ stack_t ss;
+ ss.ss_sp = alt_stack;
+ ss.ss_size = 0;
+ ss.ss_flags = SS_ONSTACK;
+ ASSERT_THAT(__llvm_libc::sigaltstack(&ss, nullptr), Fails(EINVAL));
+
+ ss.ss_flags = 0;
+ ASSERT_THAT(__llvm_libc::sigaltstack(&ss, nullptr), Fails(ENOMEM));
+}
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