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Diffstat (limited to 'include/astra/clog.h')
| -rw-r--r-- | include/astra/clog.h | 622 |
1 files changed, 622 insertions, 0 deletions
diff --git a/include/astra/clog.h b/include/astra/clog.h new file mode 100644 index 0000000..4d8e39d --- /dev/null +++ b/include/astra/clog.h @@ -0,0 +1,622 @@ +/* clog: Extremely simple logger for C. + * + * Features: + * - Implemented purely as a single header file. + * - Create multiple loggers. + * - Four log levels (debug, info, warn, error). + * - Custom formats. + * - Fast. + * + * Dependencies: + * - Should conform to C89, C++98 (but requires vsnprintf, unfortunately). + * - POSIX environment. + * + * USAGE: + * + * Include this header in any file that wishes to write to logger(s). In + * exactly one file (per executable), define CLOG_MAIN first (e.g. in your + * main .c file). + * + * #define CLOG_MAIN + * #include "clog.h" + * + * This will define the actual objects that all the other units will use. + * + * Loggers are identified by integers (0 - 15). It's expected that you'll + * create meaningful constants and then refer to the loggers as such. + * + * Example: + * + * const int MY_LOGGER = 0; + * + * int main() { + * int r; + * r = clog_init_path(MY_LOGGER, "my_log.txt"); + * if (r != 0) { + * fprintf(stderr, "Logger initialization failed.\n"); + * return 1; + * } + * clog_info(CLOG(MY_LOGGER), "Hello, world!"); + * clog_free(MY_LOGGER); + * return 0; + * } + * + * The CLOG macro used in the call to clog_info is a helper that passes the + * __FILE__ and __LINE__ parameters for you, so you don't have to type them + * every time. (It could be prettier with variadic macros, but that requires + * C99 or C++11 to be standards compliant.) + * + * Errors encountered by clog will be printed to stderr. You can suppress + * these by defining a macro called CLOG_SILENT before including clog.h. + * + * License: Do whatever you want. It would be nice if you contribute + * improvements as pull requests here: + * + * https://github.com/mmueller/clog + * + * Copyright 2013 Mike Mueller <mike@subfocal.net>. + * + * As is; no warranty is provided; use at your own risk. + */ + +#ifndef __CLOG_H__ +#define __CLOG_H__ + +#include <sys/types.h> +#include <sys/stat.h> +#include <errno.h> +#include <fcntl.h> +#include <stdarg.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <time.h> +#include <unistd.h> + +/* Number of loggers that can be defined. */ +#define CLOG_MAX_LOGGERS 16 + +/* Format strings cannot be longer than this. */ +#define CLOG_FORMAT_LENGTH 256 + +/* Formatted times and dates should be less than this length. If they are not, + * they will not appear in the log. */ +#define CLOG_DATETIME_LENGTH 256 + +/* Default format strings. */ +#define CLOG_DEFAULT_FORMAT "%d %t %f(%n): %l: %m\n" +#define CLOG_DEFAULT_DATE_FORMAT "%Y-%m-%d" +#define CLOG_DEFAULT_TIME_FORMAT "%H:%M:%S" + +#ifdef __cplusplus +extern "C" { +#endif + +enum clog_level { + CLOG_DEBUG, + CLOG_INFO, + CLOG_WARN, + CLOG_ERROR +}; + +struct clog; + +/** + * Create a new logger writing to the given file path. The file will always + * be opened in append mode. + * + * @param id + * A constant integer between 0 and 15 that uniquely identifies this logger. + * + * @param path + * Path to the file where log messages will be written. + * + * @return + * Zero on success, non-zero on failure. + */ +int clog_init_path(int id, const char *const path); + +/** + * Create a new logger writing to a file descriptor. + * + * @param id + * A constant integer between 0 and 15 that uniquely identifies this logger. + * + * @param fd + * The file descriptor where log messages will be written. + * + * @return + * Zero on success, non-zero on failure. + */ +int clog_init_fd(int id, int fd); + +/** + * Destroy (clean up) a logger. You should do this at the end of execution, + * or when you are done using the logger. + * + * @param id + * The id of the logger to destroy. + */ +void clog_free(int id); + +#define CLOG(id) __FILE__, __LINE__, id + +/** + * Log functions (one per level). Call these to write messages to the log + * file. The first three arguments can be replaced with a call to the CLOG + * macro defined above, e.g.: + * + * clog_debug(CLOG(MY_LOGGER_ID), "This is a log message."); + * + * @param sfile + * The name of the source file making this log call (e.g. __FILE__). + * + * @param sline + * The line number of the call in the source code (e.g. __LINE__). + * + * @param id + * The id of the logger to write to. + * + * @param fmt + * The format string for the message (printf formatting). + * + * @param ... + * Any additional format arguments. + */ +void clog_debug(const char *sfile, int sline, int id, const char *fmt, va_list ap); +void clog_info(const char *sfile, int sline, int id, const char *fmt, va_list ap); +void clog_warn(const char *sfile, int sline, int id, const char *fmt, va_list ap); +void clog_error(const char *sfile, int sline, int id, const char *fmt, va_list ap); + +/** + * Set the minimum level of messages that should be written to the log. + * Messages below this level will not be written. By default, loggers are + * created with level == CLOG_DEBUG. + * + * @param id + * The identifier of the logger. + * + * @param level + * The new minimum log level. + * + * @return + * Zero on success, non-zero on failure. + */ +int clog_set_level(int id, enum clog_level level); + +/** + * Set the format string used for times. See strftime(3) for how this string + * should be defined. The default format string is CLOG_DEFAULT_TIME_FORMAT. + * + * @param fmt + * The new format string, which must be less than CLOG_FORMAT_LENGTH bytes. + * + * @return + * Zero on success, non-zero on failure. + */ +int clog_set_time_fmt(int id, const char *fmt); + +/** + * Set the format string used for dates. See strftime(3) for how this string + * should be defined. The default format string is CLOG_DEFAULT_DATE_FORMAT. + * + * @param fmt + * The new format string, which must be less than CLOG_FORMAT_LENGTH bytes. + * + * @return + * Zero on success, non-zero on failure. + */ +int clog_set_date_fmt(int id, const char *fmt); + +/** + * Set the format string for log messages. Here are the substitutions you may + * use: + * + * %f: Source file name generating the log call. + * %n: Source line number where the log call was made. + * %m: The message text sent to the logger (after printf formatting). + * %d: The current date, formatted using the logger's date format. + * %t: The current time, formatted using the logger's time format. + * %l: The log level (one of "DEBUG", "INFO", "WARN", or "ERROR"). + * %%: A literal percent sign. + * + * The default format string is CLOG_DEFAULT_FORMAT. + * + * @param fmt + * The new format string, which must be less than CLOG_FORMAT_LENGTH bytes. + * You probably will want to end this with a newline (\n). + * + * @return + * Zero on success, non-zero on failure. + */ +int clog_set_fmt(int id, const char *fmt); + +/* + * No need to read below this point. + */ + +/** + * The C logger structure. + */ +struct clog { + + /* The current level of this logger. Messages below it will be dropped. */ + enum clog_level level; + + /* The file being written. */ + int fd; + + /* The format specifier. */ + char fmt[CLOG_FORMAT_LENGTH]; + + /* Date format */ + char date_fmt[CLOG_FORMAT_LENGTH]; + + /* Time format */ + char time_fmt[CLOG_FORMAT_LENGTH]; + + /* Tracks whether the fd needs to be closed eventually. */ + int opened; +}; + +void _clog_err(const char *fmt, ...); + +#ifdef CLOG_MAIN +struct clog *_clog_loggers[CLOG_MAX_LOGGERS] = { 0 }; +#else +extern struct clog *_clog_loggers[CLOG_MAX_LOGGERS]; +#endif + +#ifdef CLOG_MAIN + +const char *const CLOG_LEVEL_NAMES[] = { + "DEBUG", + "INFO", + "WARN", + "ERROR", +}; + +int +clog_init_path(int id, const char *const path) +{ + int fd = open(path, O_CREAT | O_WRONLY | O_APPEND, 0666); + if (fd == -1) { + _clog_err("Unable to open %s: %s\n", path, strerror(errno)); + return 1; + } + if (clog_init_fd(id, fd)) { + close(fd); + return 1; + } + _clog_loggers[id]->opened = 1; + return 0; +} + +int +clog_init_fd(int id, int fd) +{ + struct clog *logger; + + if (_clog_loggers[id] != NULL) { + _clog_err("Logger %d already initialized.\n", id); + return 1; + } + + logger = (struct clog *) malloc(sizeof(struct clog)); + if (logger == NULL) { + _clog_err("Failed to allocate logger: %s\n", strerror(errno)); + return 1; + } + + logger->level = CLOG_DEBUG; + logger->fd = fd; + logger->opened = 0; + strcpy(logger->fmt, CLOG_DEFAULT_FORMAT); + strcpy(logger->date_fmt, CLOG_DEFAULT_DATE_FORMAT); + strcpy(logger->time_fmt, CLOG_DEFAULT_TIME_FORMAT); + + _clog_loggers[id] = logger; + return 0; +} + +void +clog_free(int id) +{ + if (_clog_loggers[id]) { + if (_clog_loggers[id]->opened) { + close(_clog_loggers[id]->fd); + } + free(_clog_loggers[id]); + _clog_loggers[id]=NULL; + } +} + +int +clog_set_level(int id, enum clog_level level) +{ + if (_clog_loggers[id] == NULL) { + return 1; + } + if ((unsigned) level > CLOG_ERROR) { + return 1; + } + _clog_loggers[id]->level = level; + return 0; +} + +int +clog_set_time_fmt(int id, const char *fmt) +{ + struct clog *logger = _clog_loggers[id]; + if (logger == NULL) { + _clog_err("clog_set_time_fmt: No such logger: %d\n", id); + return 1; + } + if (strlen(fmt) >= CLOG_FORMAT_LENGTH) { + _clog_err("clog_set_time_fmt: Format specifier too long.\n"); + return 1; + } + strcpy(logger->time_fmt, fmt); + return 0; +} + +int +clog_set_date_fmt(int id, const char *fmt) +{ + struct clog *logger = _clog_loggers[id]; + if (logger == NULL) { + _clog_err("clog_set_date_fmt: No such logger: %d\n", id); + return 1; + } + if (strlen(fmt) >= CLOG_FORMAT_LENGTH) { + _clog_err("clog_set_date_fmt: Format specifier too long.\n"); + return 1; + } + strcpy(logger->date_fmt, fmt); + return 0; +} + +int +clog_set_fmt(int id, const char *fmt) +{ + struct clog *logger = _clog_loggers[id]; + if (logger == NULL) { + _clog_err("clog_set_fmt: No such logger: %d\n", id); + return 1; + } + if (strlen(fmt) >= CLOG_FORMAT_LENGTH) { + _clog_err("clog_set_fmt: Format specifier too long.\n"); + return 1; + } + strcpy(logger->fmt, fmt); + return 0; +} + +/* Internal functions */ + +size_t +_clog_append_str(char **dst, char *orig_buf, const char *src, size_t cur_size) +{ + size_t new_size = cur_size; + + while (strlen(*dst) + strlen(src) >= new_size) { + new_size *= 2; + } + if (new_size != cur_size) { + if (*dst == orig_buf) { + *dst = (char *) malloc(new_size); + strcpy(*dst, orig_buf); + } else { + *dst = (char *) realloc(*dst, new_size); + } + } + + strcat(*dst, src); + return new_size; +} + +size_t +_clog_append_int(char **dst, char *orig_buf, long int d, size_t cur_size) +{ + char buf[40]; /* Enough for 128-bit decimal */ + if (snprintf(buf, 40, "%ld", d) >= 40) { + return cur_size; + } + return _clog_append_str(dst, orig_buf, buf, cur_size); +} + +size_t +_clog_append_time(char **dst, char *orig_buf, struct tm *lt, + const char *fmt, size_t cur_size) +{ + char buf[CLOG_DATETIME_LENGTH]; + size_t result = strftime(buf, CLOG_DATETIME_LENGTH, fmt, lt); + + if (result > 0) { + return _clog_append_str(dst, orig_buf, buf, cur_size); + } + + return cur_size; +} + +const char * +_clog_basename(const char *path) +{ + const char *slash = strrchr(path, '/'); + if (slash) { + path = slash + 1; + } +#ifdef _WIN32 + slash = strrchr(path, '\\'); + if (slash) { + path = slash + 1; + } +#endif + return path; +} + +char * +_clog_format(const struct clog *logger, char buf[], size_t buf_size, + const char *sfile, int sline, const char *level, + const char *message) +{ + size_t cur_size = buf_size; + char *result = buf; + enum { NORMAL, SUBST } state = NORMAL; + size_t fmtlen = strlen(logger->fmt); + size_t i; + time_t t = time(NULL); + struct tm *lt = localtime(&t); + + sfile = _clog_basename(sfile); + result[0] = 0; + for (i = 0; i < fmtlen; ++i) { + if (state == NORMAL) { + if (logger->fmt[i] == '%') { + state = SUBST; + } else { + char str[2] = { 0 }; + str[0] = logger->fmt[i]; + cur_size = _clog_append_str(&result, buf, str, cur_size); + } + } else { + switch (logger->fmt[i]) { + case '%': + cur_size = _clog_append_str(&result, buf, "%", cur_size); + break; + case 't': + cur_size = _clog_append_time(&result, buf, lt, + logger->time_fmt, cur_size); + break; + case 'd': + cur_size = _clog_append_time(&result, buf, lt, + logger->date_fmt, cur_size); + break; + case 'l': + cur_size = _clog_append_str(&result, buf, level, cur_size); + break; + case 'n': + cur_size = _clog_append_int(&result, buf, sline, cur_size); + break; + case 'f': + cur_size = _clog_append_str(&result, buf, sfile, cur_size); + break; + case 'm': + cur_size = _clog_append_str(&result, buf, message, + cur_size); + break; + } + state = NORMAL; + } + } + + return result; +} + +void +_clog_log(const char *sfile, int sline, enum clog_level level, + int id, const char *fmt, va_list ap) +{ + /* For speed: Use a stack buffer until message exceeds 4096, then switch + * to dynamically allocated. This should greatly reduce the number of + * memory allocations (and subsequent fragmentation). */ + char buf[4096]; + size_t buf_size = 4096; + char *dynbuf = buf; + char *message; + int result; + struct clog *logger = _clog_loggers[id]; + + if (!logger) { + _clog_err("No such logger: %d\n", id); + return; + } + + if (level < logger->level) { + return; + } + + /* Format the message text with the argument list. */ + result = vsnprintf(dynbuf, buf_size, fmt, ap); + if ((size_t) result >= buf_size) { + buf_size = result + 1; + dynbuf = (char *) malloc(buf_size); + result = vsnprintf(dynbuf, buf_size, fmt, ap); + if ((size_t) result >= buf_size) { + /* Formatting failed -- too large */ + _clog_err("Formatting failed (1).\n"); + free(dynbuf); + return; + } + } + + /* Format according to log format and write to log */ + { + char message_buf[4096]; + message = _clog_format(logger, message_buf, 4096, sfile, sline, + CLOG_LEVEL_NAMES[level], dynbuf); + if (!message) { + _clog_err("Formatting failed (2).\n"); + if (dynbuf != buf) { + free(dynbuf); + } + return; + } + result = write(logger->fd, message, strlen(message)); + if (result == -1) { + _clog_err("Unable to write to log file: %s\n", strerror(errno)); + } + if (message != message_buf) { + free(message); + } + if (dynbuf != buf) { + free(dynbuf); + } + fsync(logger->fd); + } +} + +void +clog_debug(const char *sfile, int sline, int id, const char *fmt, va_list ap) +{ + _clog_log(sfile, sline, CLOG_DEBUG, id, fmt, ap); +} + +void +clog_info(const char *sfile, int sline, int id, const char *fmt, va_list ap) +{ + _clog_log(sfile, sline, CLOG_INFO, id, fmt, ap); +} + +void +clog_warn(const char *sfile, int sline, int id, const char *fmt, va_list ap) +{ + _clog_log(sfile, sline, CLOG_WARN, id, fmt, ap); +} + +void +clog_error(const char *sfile, int sline, int id, const char *fmt, va_list ap) +{ + _clog_log(sfile, sline, CLOG_ERROR, id, fmt, ap); +} + +void +_clog_err(const char *fmt, ...) +{ +#ifdef CLOG_SILENT + (void) fmt; +#else + va_list ap; + + va_start(ap, fmt); + vfprintf(stderr, fmt, ap); +#endif +} + +#endif /* CLOG_MAIN */ + +#ifdef __cplusplus +} /* extern "C" */ +#endif + +#endif /* __CLOG_H__ */ |