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authorGravatar Andy Getzendanner <durandal@google.com>2022-05-04 20:58:05 -0700
committerGravatar Copybara-Service <copybara-worker@google.com>2022-05-04 20:58:54 -0700
commit173dfe4a4c70f294a512aae4d0d0f5fc7db39241 (patch)
tree69713a45f8fb1ad3874a0f7e1e0a50b40f7d001a /absl
parente8cda74967d1fa43182f88396e9030e93501e1a1 (diff)
raw_logging: Rename SafeWriteToStderr to indicate what about it is safe (answer: it's async-signal-safe).
Also, preserve errno across calls to make it actually signal-safe. PiperOrigin-RevId: 446620926 Change-Id: I875fbec02b909e8424ddf763303b0d6007f8548f
Diffstat (limited to 'absl')
-rw-r--r--absl/base/BUILD.bazel1
-rw-r--r--absl/base/CMakeLists.txt1
-rw-r--r--absl/base/internal/raw_logging.cc8
-rw-r--r--absl/base/internal/raw_logging.h9
-rw-r--r--absl/debugging/BUILD.bazel1
-rw-r--r--absl/debugging/CMakeLists.txt1
-rw-r--r--absl/debugging/failure_signal_handler.cc4
7 files changed, 12 insertions, 13 deletions
diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index 49e3a95f..b7e49359 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -75,6 +75,7 @@ cc_library(
":atomic_hook",
":config",
":core_headers",
+ ":errno_saver",
":log_severity",
],
)
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index 0e1e0413..ed55093a 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -66,6 +66,7 @@ absl_cc_library(
absl::atomic_hook
absl::config
absl::core_headers
+ absl::errno_saver
absl::log_severity
COPTS
${ABSL_DEFAULT_COPTS}
diff --git a/absl/base/internal/raw_logging.cc b/absl/base/internal/raw_logging.cc
index acf20f2a..ca2a75f3 100644
--- a/absl/base/internal/raw_logging.cc
+++ b/absl/base/internal/raw_logging.cc
@@ -24,6 +24,7 @@
#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/internal/atomic_hook.h"
+#include "absl/base/internal/errno_saver.h"
#include "absl/base/log_severity.h"
// We know how to perform low-level writes to stderr in POSIX and Windows. For
@@ -169,7 +170,7 @@ void RawLogVA(absl::LogSeverity severity, const char* file, int line,
} else {
DoRawLog(&buf, &size, "%s", kTruncated);
}
- SafeWriteToStderr(buffer, strlen(buffer));
+ AsyncSignalSafeWriteToStderr(buffer, strlen(buffer));
}
#else
static_cast<void>(format);
@@ -196,8 +197,11 @@ void DefaultInternalLog(absl::LogSeverity severity, const char* file, int line,
} // namespace
-void SafeWriteToStderr(const char *s, size_t len) {
+void AsyncSignalSafeWriteToStderr(const char* s, size_t len) {
+ absl::base_internal::ErrnoSaver errno_saver;
#if defined(ABSL_HAVE_SYSCALL_WRITE)
+ // We prefer calling write via `syscall` to minimize the risk of libc doing
+ // something "helpful".
syscall(SYS_write, STDERR_FILENO, s, len);
#elif defined(ABSL_HAVE_POSIX_WRITE)
write(STDERR_FILENO, s, len);
diff --git a/absl/base/internal/raw_logging.h b/absl/base/internal/raw_logging.h
index efe28dac..68a8bf21 100644
--- a/absl/base/internal/raw_logging.h
+++ b/absl/base/internal/raw_logging.h
@@ -109,12 +109,9 @@ namespace raw_logging_internal {
void RawLog(absl::LogSeverity severity, const char* file, int line,
const char* format, ...) ABSL_PRINTF_ATTRIBUTE(4, 5);
-// Writes the provided buffer directly to stderr, in a safe, low-level manner.
-//
-// In POSIX this means calling write(), which is async-signal safe and does
-// not malloc. If the platform supports the SYS_write syscall, we invoke that
-// directly to side-step any libc interception.
-void SafeWriteToStderr(const char *s, size_t len);
+// Writes the provided buffer directly to stderr, in a signal-safe, low-level
+// manner.
+void AsyncSignalSafeWriteToStderr(const char* s, size_t len);
// compile-time function to get the "base" filename, that is, the part of
// a filename after the last "/" or "\" path separator. The search starts at
diff --git a/absl/debugging/BUILD.bazel b/absl/debugging/BUILD.bazel
index 7f5c1cad..dce59e1d 100644
--- a/absl/debugging/BUILD.bazel
+++ b/absl/debugging/BUILD.bazel
@@ -143,7 +143,6 @@ cc_library(
"//absl/base",
"//absl/base:config",
"//absl/base:core_headers",
- "//absl/base:errno_saver",
"//absl/base:raw_logging_internal",
],
)
diff --git a/absl/debugging/CMakeLists.txt b/absl/debugging/CMakeLists.txt
index 7507ff3b..32952734 100644
--- a/absl/debugging/CMakeLists.txt
+++ b/absl/debugging/CMakeLists.txt
@@ -126,7 +126,6 @@ absl_cc_library(
absl::base
absl::config
absl::core_headers
- absl::errno_saver
absl::raw_logging_internal
PUBLIC
)
diff --git a/absl/debugging/failure_signal_handler.cc b/absl/debugging/failure_signal_handler.cc
index 3fe8827a..affade3b 100644
--- a/absl/debugging/failure_signal_handler.cc
+++ b/absl/debugging/failure_signal_handler.cc
@@ -42,7 +42,6 @@
#include <ctime>
#include "absl/base/attributes.h"
-#include "absl/base/internal/errno_saver.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/base/internal/sysinfo.h"
#include "absl/debugging/internal/examine_stack.h"
@@ -217,8 +216,7 @@ static void InstallOneFailureHandler(FailureSignalData* data,
#endif
static void WriteToStderr(const char* data) {
- absl::base_internal::ErrnoSaver errno_saver;
- absl::raw_logging_internal::SafeWriteToStderr(data, strlen(data));
+ absl::raw_logging_internal::AsyncSignalSafeWriteToStderr(data, strlen(data));
}
static void WriteSignalMessage(int signo, int cpu,