| // Copyright (c) 2010 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| /* |
| * metrics_library.cc |
| * |
| * Created on: Dec 1, 2009 |
| * Author: sosa |
| */ |
| |
| #include "metrics_library.h" |
| |
| #include <errno.h> |
| #include <sys/file.h> |
| |
| #include <cstdarg> |
| #include <cstdio> |
| #include <cstring> |
| |
| #define READ_WRITE_ALL_FILE_FLAGS \ |
| (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH) |
| |
| static const char kAutotestPath[] = |
| "/var/log/metrics/autotest-events"; |
| static const char kChromePath[] = |
| "/var/log/metrics/uma-events"; |
| static const int32_t kBufferSize = 1024; |
| |
| using namespace std; |
| |
| // TODO(sosa@chromium.org) - use Chromium logger instead of stderr |
| static void PrintError(const char *message, const char *file, |
| int code) { |
| const char *kProgramName = "metrics_library"; |
| if (code == 0) { |
| fprintf(stderr, "%s: %s\n", kProgramName, message); |
| } else if (file == NULL) { |
| fprintf(stderr, "%s: ", kProgramName); |
| perror(message); |
| } else { |
| fprintf(stderr, "%s: %s: ", kProgramName, file); |
| perror(message); |
| } |
| } |
| |
| // Sends message of size |length| to Chrome and returns true on success. |
| static bool SendMessageToChrome(int32_t length, const char *message) { |
| int chrome_fd = open(kChromePath, |
| O_WRONLY | O_APPEND | O_CREAT, |
| READ_WRITE_ALL_FILE_FLAGS); |
| // If we failed to open it, return. |
| if (chrome_fd < 0) { |
| PrintError("open", kChromePath, errno); |
| return false; |
| } |
| |
| // Need to chmod because open flags are anded with umask. Ignore the |
| // exit code -- a chronos process may fail chmoding because the file |
| // has been created by a root process but that should be OK. |
| fchmod(chrome_fd, READ_WRITE_ALL_FILE_FLAGS); |
| |
| // Grab an exclusive lock to protect Chrome from truncating |
| // underneath us. Keep the file locked as briefly as possible. |
| if (flock(chrome_fd, LOCK_EX) < 0) { |
| PrintError("flock", kChromePath, errno); |
| close(chrome_fd); |
| return false; |
| } |
| |
| bool success = true; |
| if (write(chrome_fd, message, length) != length) { |
| PrintError("write", kChromePath, errno); |
| success = false; |
| } |
| |
| // Release the file lock and close file. |
| if (flock(chrome_fd, LOCK_UN) < 0) { |
| PrintError("unlock", kChromePath, errno); |
| success = false; |
| } |
| close(chrome_fd); |
| return success; |
| } |
| |
| // Formats a name/value message for Chrome in |buffer| and returns the |
| // length of the message or a negative value on error. |
| // |
| // Message format is: | LENGTH(binary) | NAME | \0 | VALUE | \0 | |
| // |
| // The arbitrary |format| argument covers the non-LENGTH portion of the |
| // message. The caller is responsible to store the \0 character |
| // between NAME and VALUE (e.g. "%s%c%d", name, '\0', value). |
| static int32_t FormatChromeMessage(int32_t buffer_size, char *buffer, |
| const char *format, ...) { |
| int32_t message_length; |
| size_t len_size = sizeof(message_length); |
| |
| // Format the non-LENGTH contents in the buffer by leaving space for |
| // LENGTH at the start of the buffer. |
| va_list args; |
| va_start(args, format); |
| message_length = vsnprintf(&buffer[len_size], buffer_size - len_size, |
| format, args); |
| va_end(args); |
| |
| if (message_length < 0) { |
| PrintError("chrome message format error", NULL, 0); |
| return -1; |
| } |
| |
| // +1 to account for the trailing \0. |
| message_length += len_size + 1; |
| if (message_length > buffer_size) { |
| PrintError("chrome message too long", NULL, 0); |
| return -1; |
| } |
| |
| // Prepend LENGTH to the message. |
| memcpy(buffer, &message_length, len_size); |
| return message_length; |
| } |
| |
| // static |
| bool MetricsLibrary::SendToAutotest(const string& name, int value) { |
| FILE *autotest_file = fopen(kAutotestPath, "a+"); |
| if (autotest_file == NULL) { |
| PrintError("fopen", kAutotestPath, errno); |
| return false; |
| } |
| |
| fprintf(autotest_file, "%s=%d\n", name.c_str(), value); |
| fclose(autotest_file); |
| return true; |
| } |
| |
| // static |
| bool MetricsLibrary::SendToChrome(const string& name, int sample, |
| int min, int max, int nbuckets) { |
| // Format the message. |
| char message[kBufferSize]; |
| int32_t message_length = |
| FormatChromeMessage(kBufferSize, message, |
| "histogram%c%s %d %d %d %d", '\0', |
| name.c_str(), sample, min, max, nbuckets); |
| |
| if (message_length < 0) |
| return false; |
| |
| // Send the message. |
| return SendMessageToChrome(message_length, message); |
| } |