Merge "liblog: always restore errno in logging functions"

base/include/android-base/errno_restorer.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "errno.h"
+
+#include "android-base/macros.h"
+
+namespace android {
+namespace base {
+
+class ErrnoRestorer {
+ public:
+  ErrnoRestorer() : saved_errno_(errno) {}
+
+  ~ErrnoRestorer() { errno = saved_errno_; }
+
+  // Allow this object to be used as part of && operation.
+  operator bool() const { return true; }
+
+ private:
+  const int saved_errno_;
+
+  DISALLOW_COPY_AND_ASSIGN(ErrnoRestorer);
+};
+
+}  // namespace base
+}  // namespace android

base/include/android-base/logging.h

@@ -64,6 +64,7 @@
 #include <memory>
 #include <ostream>
 
+#include "android-base/errno_restorer.h"
 #include "android-base/macros.h"
 
 // Note: DO NOT USE DIRECTLY. Use LOG_TAG instead.
@@ -154,27 +155,6 @@ void SetLogger(LogFunction&& logger);
 // Replace the current aborter.
 void SetAborter(AbortFunction&& aborter);
 
-class ErrnoRestorer {
- public:
-  ErrnoRestorer()
-      : saved_errno_(errno) {
-  }
-
-  ~ErrnoRestorer() {
-    errno = saved_errno_;
-  }
-
-  // Allow this object to be used as part of && operation.
-  operator bool() const {
-    return true;
-  }
-
- private:
-  const int saved_errno_;
-
-  DISALLOW_COPY_AND_ASSIGN(ErrnoRestorer);
-};
-
 // A helper macro that produces an expression that accepts both a qualified name and an
 // unqualified name for a LogSeverity, and returns a LogSeverity value.
 // Note: DO NOT USE DIRECTLY. This is an implementation detail.

liblog/logger_write.cpp

@@ -29,6 +29,7 @@
 
 #include <shared_mutex>
 
+#include <android-base/errno_restorer.h>
 #include <android-base/macros.h>
 #include <private/android_filesystem_config.h>
 #include <private/android_logger.h>
@@ -54,6 +55,8 @@
 #include <windows.h>
 #endif
 
+using android::base::ErrnoRestorer;
+
 #define LOG_BUF_SIZE 1024
 
 #if defined(__ANDROID__)
@@ -196,11 +199,9 @@ void __android_log_call_aborter(const char* abort_message) {
 
 #ifdef __ANDROID__
 static int write_to_log(log_id_t log_id, struct iovec* vec, size_t nr) {
-  int ret, save_errno;
+  int ret;
   struct timespec ts;
 
-  save_errno = errno;
-
   if (log_id == LOG_ID_KERNEL) {
     return -EINVAL;
   }
@@ -209,23 +210,19 @@ static int write_to_log(log_id_t log_id, struct iovec* vec, size_t nr) {
 
   if (log_id == LOG_ID_SECURITY) {
     if (vec[0].iov_len < 4) {
-      errno = save_errno;
       return -EINVAL;
     }
 
     ret = check_log_uid_permissions();
     if (ret < 0) {
-      errno = save_errno;
       return ret;
     }
     if (!__android_log_security()) {
       /* If only we could reset downstream logd counter */
-      errno = save_errno;
       return -EPERM;
     }
   } else if (log_id == LOG_ID_EVENTS || log_id == LOG_ID_STATS) {
     if (vec[0].iov_len < 4) {
-      errno = save_errno;
       return -EINVAL;
     }
   }
@@ -233,7 +230,6 @@ static int write_to_log(log_id_t log_id, struct iovec* vec, size_t nr) {
   ret = LogdWrite(log_id, &ts, vec, nr);
   PmsgWrite(log_id, &ts, vec, nr);
 
-  errno = save_errno;
   return ret;
 }
 #else
@@ -313,6 +309,8 @@ int __android_log_write(int prio, const char* tag, const char* msg) {
 }
 
 void __android_log_write_logger_data(__android_logger_data* logger_data, const char* msg) {
+  ErrnoRestorer errno_restorer;
+
   auto tag_lock = std::shared_lock{default_tag_lock, std::defer_lock};
   if (logger_data->tag == nullptr) {
     tag_lock.lock();
@@ -330,6 +328,8 @@ void __android_log_write_logger_data(__android_logger_data* logger_data, const c
 }
 
 int __android_log_buf_write(int bufID, int prio, const char* tag, const char* msg) {
+  ErrnoRestorer errno_restorer;
+
   if (!__android_log_is_loggable(prio, tag, ANDROID_LOG_VERBOSE)) {
     return 0;
   }
@@ -340,6 +340,8 @@ int __android_log_buf_write(int bufID, int prio, const char* tag, const char* ms
 }
 
 int __android_log_vprint(int prio, const char* tag, const char* fmt, va_list ap) {
+  ErrnoRestorer errno_restorer;
+
   if (!__android_log_is_loggable(prio, tag, ANDROID_LOG_VERBOSE)) {
     return 0;
   }
@@ -355,6 +357,8 @@ int __android_log_vprint(int prio, const char* tag, const char* fmt, va_list ap)
 }
 
 int __android_log_print(int prio, const char* tag, const char* fmt, ...) {
+  ErrnoRestorer errno_restorer;
+
   if (!__android_log_is_loggable(prio, tag, ANDROID_LOG_VERBOSE)) {
     return 0;
   }
@@ -373,6 +377,8 @@ int __android_log_print(int prio, const char* tag, const char* fmt, ...) {
 }
 
 int __android_log_buf_print(int bufID, int prio, const char* tag, const char* fmt, ...) {
+  ErrnoRestorer errno_restorer;
+
   if (!__android_log_is_loggable(prio, tag, ANDROID_LOG_VERBOSE)) {
     return 0;
   }
@@ -419,6 +425,8 @@ void __android_log_assert(const char* cond, const char* tag, const char* fmt, ..
 }
 
 int __android_log_bwrite(int32_t tag, const void* payload, size_t len) {
+  ErrnoRestorer errno_restorer;
+
   struct iovec vec[2];
 
   vec[0].iov_base = &tag;
@@ -430,6 +438,8 @@ int __android_log_bwrite(int32_t tag, const void* payload, size_t len) {
 }
 
 int __android_log_stats_bwrite(int32_t tag, const void* payload, size_t len) {
+  ErrnoRestorer errno_restorer;
+
   struct iovec vec[2];
 
   vec[0].iov_base = &tag;
@@ -441,6 +451,8 @@ int __android_log_stats_bwrite(int32_t tag, const void* payload, size_t len) {
 }
 
 int __android_log_security_bwrite(int32_t tag, const void* payload, size_t len) {
+  ErrnoRestorer errno_restorer;
+
   struct iovec vec[2];
 
   vec[0].iov_base = &tag;
@@ -457,6 +469,8 @@ int __android_log_security_bwrite(int32_t tag, const void* payload, size_t len)
  * handy if we just want to dump an integer into the log.
  */
 int __android_log_btwrite(int32_t tag, char type, const void* payload, size_t len) {
+  ErrnoRestorer errno_restorer;
+
   struct iovec vec[3];
 
   vec[0].iov_base = &tag;
@@ -474,6 +488,8 @@ int __android_log_btwrite(int32_t tag, char type, const void* payload, size_t le
  * event log.
  */
 int __android_log_bswrite(int32_t tag, const char* payload) {
+  ErrnoRestorer errno_restorer;
+
   struct iovec vec[4];
   char type = EVENT_TYPE_STRING;
   uint32_t len = strlen(payload);
@@ -495,6 +511,8 @@ int __android_log_bswrite(int32_t tag, const char* payload) {
  * security log.
  */
 int __android_log_security_bswrite(int32_t tag, const char* payload) {
+  ErrnoRestorer errno_restorer;
+
   struct iovec vec[4];
   char type = EVENT_TYPE_STRING;
   uint32_t len = strlen(payload);