f1e83cc34a
It seemed like a clever trick to use the internal log message formatting code in syslog(3), but on reflection that means you can't (for example) format floating point numbers. This patch switches us over to using good old vsnprintf(3), even though that requires us to jump through a few hoops. There's no obvious way to unit test this, so I wrote a little program and ran that. (cherry-pick of b1b60c30bf321c0fc02264b953b5c16c49d34457.) Bug: 14292866 Change-Id: I9c83500ba9cbb209b6f496067a91bf69434eeef5
121 lines
3.3 KiB
C++
121 lines
3.3 KiB
C++
/*
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* Copyright (C) 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <errno.h>
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#include <stdlib.h>
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#include <syslog.h>
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#include "private/libc_logging.h"
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static const char* syslog_log_tag = NULL;
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static int syslog_priority_mask = 0xff;
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void closelog() {
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syslog_log_tag = NULL;
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}
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void openlog(const char* log_tag, int /*options*/, int /*facility*/) {
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syslog_log_tag = log_tag;
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}
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int setlogmask(int new_mask) {
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int old_mask = syslog_priority_mask;
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// 0 is used to query the current mask.
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if (new_mask != 0) {
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syslog_priority_mask = new_mask;
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}
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return old_mask;
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}
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void syslog(int priority, const char* fmt, ...) {
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va_list args;
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va_start(args, fmt);
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vsyslog(priority, fmt, args);
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va_end(args);
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}
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void vsyslog(int priority, const char* fmt, va_list args) {
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int caller_errno = errno;
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// Check whether we're supposed to be logging messages of this priority.
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if ((syslog_priority_mask & LOG_MASK(LOG_PRI(priority))) == 0) {
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return;
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}
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// What's our log tag?
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const char* log_tag = syslog_log_tag;
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if (log_tag == NULL) {
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log_tag = getprogname();
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}
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// What's our Android log priority?
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priority &= LOG_PRIMASK;
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int android_log_priority;
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if (priority <= LOG_ERR) {
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android_log_priority = ANDROID_LOG_ERROR;
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} else if (priority == LOG_WARNING) {
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android_log_priority = ANDROID_LOG_WARN;
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} else if (priority <= LOG_INFO) {
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android_log_priority = ANDROID_LOG_INFO;
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} else {
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android_log_priority = ANDROID_LOG_DEBUG;
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}
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// glibc's printf family support %m directly, but our BSD-based one doesn't.
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// If the format string seems to contain "%m", rewrite it.
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const char* log_fmt = fmt;
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if (strstr(fmt, "%m") != NULL) {
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size_t dst_len = 1024;
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char* dst = reinterpret_cast<char*>(malloc(dst_len));
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log_fmt = dst;
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const char* src = fmt;
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for (; dst_len > 0 && *src != '\0'; ++src) {
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if (*src == '%' && *(src + 1) == 'm') {
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// Expand %m.
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size_t n = strlcpy(dst, strerror(caller_errno), dst_len);
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if (n >= dst_len) {
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n = dst_len;
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}
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dst += n;
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dst_len -= n;
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++src;
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} else if (*src == '%' && *(src + 1) == '%') {
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// We need to copy pairs of '%'s so the %m test works.
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if (dst_len <= 2) {
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break;
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}
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*dst++ = '%'; --dst_len;
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*dst++ = '%'; --dst_len;
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++src;
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} else {
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*dst++ = *src; --dst_len;
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}
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}
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*dst = '\0';
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}
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// We can't let __libc_format_log do the formatting because it doesn't support
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// all the printf functionality.
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char log_line[1024];
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vsnprintf(log_line, sizeof(log_line), log_fmt, args);
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if (log_fmt != fmt) {
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free(const_cast<char*>(log_fmt));
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}
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__libc_format_log(android_log_priority, log_tag, "%s", log_line);
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}
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