#ifndef _UCW_LOG_H_
#define _UCW_LOG_H_
-#include "ucw/clists.h"
-
-/* user de/allocated program/process name for use in the logsystem */
-extern char *ls_title;
+#include <ucw/clists.h>
+
+#ifdef CONFIG_UCW_CLEAN_ABI
+#define log_add_substream ucw_log_add_substream
+#define log_check_configured ucw_log_check_configured
+#define log_close_all ucw_log_close_all
+#define log_close_stream ucw_log_close_stream
+#define log_configured ucw_log_configured
+#define log_find_type ucw_log_find_type
+#define log_new_configured ucw_log_new_configured
+#define log_new_fd ucw_log_new_fd
+#define log_new_file ucw_log_new_file
+#define log_new_stream ucw_log_new_stream
+#define log_new_syslog ucw_log_new_syslog
+#define log_pass_filtered ucw_log_pass_filtered
+#define log_register_type ucw_log_register_type
+#define log_rm_substream ucw_log_rm_substream
+#define log_set_default_stream ucw_log_set_default_stream
+#define log_set_format ucw_log_set_format
+#define log_stream_by_flags ucw_log_stream_by_flags
+#define log_switch ucw_log_switch
+#define log_switch_disable ucw_log_switch_disable
+#define log_switch_enable ucw_log_switch_enable
+#define log_syslog_facility_exists ucw_log_syslog_facility_exists
+#define log_type_name ucw_log_type_name
+#endif
-struct log_stream
-{
- /* optional name, 0-term, de/allocated by constr./destr. or user */
- char *name;
- /* number for use with msg parameter (from LS_SET_STRNUM()), -1 for closed log_stream */
- int regnum;
- /* arbitrary data for filter/handler */
- int idata;
- void *pdata;
- /* severity levels to accept - bitmask of (1<<LEVEL) */
- int levels;
- /* if filter returns nonzero, discard the message */
- int (*filter)(struct log_stream* ls, const char *m, u32 cat);
- /* pass the message to these streams (simple-list of pointers) */
- struct clist substreams;
- /* what kind of string to format to pass to the handler (bitmask of LSFMT_xxx ) */
- int msgfmt;
- /* what to do to commit the message (ret 0 on success, nonzero on error)
- * msg is 0-term string, with desired info, one line, ending with "\n\0". */
- int (*handler)(struct log_stream* ls, const char *m, u32 cat);
- /* close the log_stream file/connection */
- void (*close)(struct log_stream* ls);
+/*** === Messages and streams ***/
+
+/**
+ * Inside the logging system, a log message is always represented by this structure.
+ **/
+struct log_msg {
+ char *m; // The formatted message itself, ending with \n\0
+ int m_len; // Length without the \0
+ struct tm *tm; // Current time
+ struct timeval *tv;
+ uint flags; // Category and other flags as passed to msg()
+ char *raw_msg; // Unformatted parts
+ char *stime;
+ char *sutime;
+ uint depth; // Recursion depth
+ bool error; // An error has occurred (e.g., an infinite loop in sub-streams)
};
-/* the default logger */
-extern const struct log_stream ls_default_log;
-
-/* A message is processed as follows:
- * 1. Discard if message level not in levels
- * 2. Run filter (if any), discard if ret. nonzero
- * 3. Pass the message to all log_streams in substreams
- * 4. Format the message informaion acc. to msgfmt
- * 5. Run the handler
- */
-
-/* log header verbosity specifying message passed to handler */
-enum ls_fmt
-{
- LSFMT_LEVEL=1, /* log severity level (one letter) */
- LSFMT_TIME=2, /* log time (date-seconds) */
- LSFMT_USEC=4, /* log also micro-seconds */
- LSFMT_TITLE=8, /* log program title (global string) */
- LSFMT_PID=16, /* log program PID */
- LSFMT_LOGNAME=32, /* log log_stream name */
- LSFMT_NONE=0,
- LSFMT_FULL=LSFMT_LEVEL+LSFMT_TIME+LSFMT_USEC+LSFMT_TITLE+LSFMT_PID+LSFMT_LOGNAME,
- LSFMT_DEFAULT=LSFMT_LEVEL+LSFMT_TIME
+/**
+ * Each stream is represented by an instance of this structure.
+ **/
+struct log_stream {
+ char *name; // Optional name, allocated by the user (or constructor)
+ int regnum; // Stream number, already encoded by LS_SET_STRNUM(); -1 if closed
+ uint levels; // Bitmask of accepted severity levels (default: all)
+ uint types; // Bitmask of accepted message types (default: all)
+ uint msgfmt; // Formatting flags (LSFMT_xxx)
+ uint use_count; // Number of references to the stream
+ uint stream_flags; // Various other flags (LSFLAG_xxx)
+ int (*filter)(struct log_stream* ls, struct log_msg *m); // Filter function, return non-zero to discard the message
+ clist substreams; // Pass the message to these streams (simple_list of pointers)
+ int (*handler)(struct log_stream *ls, struct log_msg *m); // Called to commit the message, return 0 for success, errno on error
+ void (*close)(struct log_stream* ls); // Called upon log_close_stream()
+ void *user_data; // Not used by the logging system
+ // Private data of the handler follow
};
-/* Mask of containing all existing levels. */
-#define LS_ALL_LEVELS 0xfff
+/**
+ * Formatting flags specifying the format of the message passed to the handler.
+ **/
+enum ls_fmt {
+ LSFMT_LEVEL = 1, // severity level (one letter) */
+ LSFMT_TIME = 2, // date and time (YYYY-mm-dd HH:MM:SS) */
+ LSFMT_USEC = 4, // also micro-seconds */
+ LSFMT_TITLE = 8, // program title (log_title) */
+ LSFMT_PID = 16, // program PID (log_pid) */
+ LSFMT_LOGNAME = 32, // name of the log_stream */
+ LSFMT_TYPE = 64, // message type
+};
-// return the letter associated with the severity level
-#define LS_LEVEL_LETTER(level) ("DIiWwEe!###"[( level )])
+#define LSFMT_DEFAULT (LSFMT_LEVEL | LSFMT_TIME | LSFMT_TITLE | LSFMT_PID) /** Default format **/
-///// Macros for extracting parts of the flags parameter
-// The division of the flags parameter is decided only here
-// The current division is (for 32 bit flags):
-// MSB <5 bits: any internal log flags> <8 bits: "user" flags> <10 bits: stream number>
-// <8 bits: severity level> LSB
+/**
+ * General stream flags.
+ **/
+enum ls_flag {
+ LSFLAG_ERR_IS_FATAL = 1, // When a logging error occurs, die() immediately
+ LSFLAG_ERR_REPORTED = 2, // A logging error has been already reported on this stream
+};
-// Bits per section
-enum ls_flagbits {
- LS_LEVEL_BITS = 8,
- LS_STRNUM_BITS = 16,
- LS_FLAGS_BITS = 5,
- LS_INTERNAL_BITS = 4,
+/***
+ * === Message flags
+ *
+ * The @flags parameter of <<basics:msg()>> is divided to several groups of bits (from the LSB):
+ * message severity level (`L_xxx`), destination stream, message type
+ * and control bits (e.g., `L_SIGHANDLER`).
+ ***/
+
+enum ls_flagbits { // Bit widths of groups
+ LS_LEVEL_BITS = 8,
+ LS_STRNUM_BITS = 16,
+ LS_TYPE_BITS = 5,
+ LS_CTRL_BITS = 3,
};
-// Section shifts
-enum ls_flagpos {
- LS_LEVEL_POS = 0,
- LS_STRNUM_POS = LS_LEVEL_POS + LS_LEVEL_BITS,
- LS_FLAGS_POS = LS_STRNUM_POS + LS_STRNUM_BITS,
- LS_INTERNAL_POS = LS_FLAGS_POS + LS_FLAGS_BITS,
+enum ls_flagpos { // Bit positions of groups
+ LS_LEVEL_POS = 0,
+ LS_STRNUM_POS = LS_LEVEL_POS + LS_LEVEL_BITS,
+ LS_TYPE_POS = LS_STRNUM_POS + LS_STRNUM_BITS,
+ LS_CTRL_POS = LS_TYPE_POS + LS_TYPE_BITS,
};
-// Bitmasks
-enum ls_flagmasks {
- LS_LEVEL_MASK = (( 1 << LS_LEVEL_BITS ) - 1 ) << LS_LEVEL_POS,
- LS_STRNUM_MASK = (( 1 << LS_STRNUM_BITS ) - 1 ) << LS_STRNUM_POS,
- LS_FLAGS_MASK = (( 1 << LS_FLAGS_BITS ) - 1 ) << LS_FLAGS_POS,
- LS_INTERNAL_MASK = (( 1 << LS_INTERNAL_BITS ) - 1 ) << LS_INTERNAL_POS,
+enum ls_flagmasks { // Bit masks of groups
+ LS_LEVEL_MASK = ((1 << LS_LEVEL_BITS) - 1) << LS_LEVEL_POS,
+ LS_STRNUM_MASK = ((1 << LS_STRNUM_BITS) - 1) << LS_STRNUM_POS,
+ LS_TYPE_MASK = ((1 << LS_TYPE_BITS) - 1) << LS_TYPE_POS,
+ LS_CTRL_MASK = ((1 << LS_CTRL_BITS) - 1) << LS_CTRL_POS,
};
// "Get" macros (break flags to parts)
-#define LS_GET_LEVEL(flags) ((( flags ) & LS_LEVEL_MASK ) >> LS_LEVEL_POS )
-#define LS_GET_STRNUM(flags) ((( flags ) & LS_STRNUM_MASK ) >> LS_STRNUM_POS )
-#define LS_GET_FLAGS(flags) ((( flags ) & LS_FLAGS_MASK ) >> LS_FLAGS_POS )
-#define LS_GET_INTERNAL(flags) ((( flags ) & LS_INTERNAL_MASK ) >> LS_INTERNAL_POS )
+#define LS_GET_LEVEL(flags) (((flags) & LS_LEVEL_MASK) >> LS_LEVEL_POS) /** Extract severity level **/
+#define LS_GET_STRNUM(flags) (((flags) & LS_STRNUM_MASK) >> LS_STRNUM_POS) /** Extract stream number **/
+#define LS_GET_TYPE(flags) (((flags) & LS_TYPE_MASK) >> LS_TYPE_POS) /** Extract message type **/
+#define LS_GET_CTRL(flags) (((flags) & LS_CTRL_MASK) >> LS_CTRL_POS) /** Extract control bits **/
// "Set" macros (parts to flags)
-#define LS_SET_LEVEL(level) (( level ) << LS_LEVEL_POS )
-#define LS_SET_STRNUM(strnum) (( strnum ) << LS_STRNUM_POS )
-#define LS_SET_FLAGS(flags) (( flags ) << LS_FLAGS_POS )
-#define LS_SET_INTERNAL(intern) (( intern ) << LS_INTERNAL_POS )
-
-// Internal flags of the logsystem
-// Avoid operations that are unsafe in signal handlers
-#define LSFLAG_SIGHANDLER LS_SET_INTERNAL(0x001)
-
-// The module is initialized when a first stream is created.
-// Before that only the default stream exists.
-
-// Initial number of streams to allocate (must be >=2)
-#define LS_INIT_STREAMS 8
-
-/* Return pointer a new (xmalloc()-ated) stream with no handler and an empty substream list. */
-struct log_stream *ls_new(void);
-
-/* Close and xfree() given log_stream */
-/* Does not affect substreams */
-void ls_close(struct log_stream *ls);
-
-/* close all open streams, un-initialize the module, free all memory,
- * use only ls_default_log */
-void ls_close_all(void);
-
-/* add a new substream, xmalloc()-ate a new simp_node */
-void ls_add_substream(struct log_stream *where, struct log_stream *what);
-
-/* remove all occurences of a substream, free() the simp_node */
-/* return number of deleted entries */
-int ls_rm_substream(struct log_stream *where, struct log_stream *what);
-
-/* get a stream by its number (regnum) */
-/* returns NULL for free numbers */
-/* defaults to ls_default_stream for 0 when stream number 0 not set */
-struct log_stream *log_stream_by_flags(uns flags);
-
-/* The proposed alternative to original vmsg() */
-void ls_vmsg(unsigned int cat, const char *fmt, va_list args);
-
-/* The proposed alternative to original msg() */
-void ls_msg(unsigned int cat, const char *fmt, ...);
-
-/* The proposed alternative to original die() */
-void ls_die(const char *fmt, ...);
-
-/* process a message (string) (INTERNAL) */
-/* depth prevents undetected looping */
-/* returns 1 in case of loop detection or other fatal error
- * 0 otherwise */
-int ls_passmsg(int depth, struct log_stream *ls, const char *stime, const char *sutime,
- const char *msg, u32 cat);
-
-/* Maximal depth of ls_passmsg recursion */
-#define LS_MAX_DEPTH 64
-
-/* Define an array (growing buffer) for pointers to log_streams. */
-#define GBUF_TYPE struct log_stream*
-#define GBUF_PREFIX(x) lsbuf_##x
-#include "ucw/gbuf.h"
-
-extern struct lsbuf_t log_streams;
-extern int log_streams_after;
-
-/********* Individual handler types (constructors, handlers, destructors) */
-
-/**** standard (filedes) files */
-
-// NOTE:
-// under unix, for ordinary files open in append mode, the writes
-// are atomic (unless you meet the quota or other bad things happen),
-// so using a single log_stream is thread-safe and the file can be shared
-// among multiple processes
-
-/* assign log to a file descriptor */
-/* initialize with the default formatting, does NOT close the descriptor */
-struct log_stream *ls_fdfile_new(int fd);
-
-/* open() a file (append mode) */
-/* initialize with the default formatting */
-struct log_stream *ls_file_new(const char *path);
+#define LS_SET_LEVEL(level) ((level) << LS_LEVEL_POS) /** Convert severity level to flags **/
+#define LS_SET_STRNUM(strnum) ((strnum) << LS_STRNUM_POS) /** Convert stream number to flags **/
+#define LS_SET_TYPE(type) ((type) << LS_TYPE_POS) /** Convert message type to flags **/
+#define LS_SET_CTRL(ctrl) ((ctrl) << LS_CTRL_POS) /** Convert control bits to flags **/
+
+#define LS_NUM_TYPES (1 << LS_TYPE_BITS)
+
+/** Register a new message type and return the corresponding flag set (encoded by `LS_SET_TYPE`). **/
+int log_register_type(const char *name);
+
+/** Find a message type by name and return the corresponding flag set. Returns -1 if no such type found. **/
+int log_find_type(const char *name);
+
+/** Given a flag set, extract the message type ID and return its name. **/
+char *log_type_name(uint flags);
+
+/*** === Operations on streams ***/
+
+/**
+ * Allocate a new log stream with no handler and an empty substream list.
+ * Since struct log_stream is followed by private data, @size bytes of memory are allocated
+ * for the whole structure. See below for functions creating specific stream types.
+ **/
+struct log_stream *log_new_stream(size_t size);
+
+/**
+ * Decrement the use count of a stream. If it becomes zero, close the stream,
+ * free its memory, and unlink all its substreams.
+ **/
+int log_close_stream(struct log_stream *ls);
+
+/**
+ * Get a new reference on an existing stream. For convenience, the return value is
+ * equal to the argument @ls.
+ **/
+static inline struct log_stream *log_ref_stream(struct log_stream *ls)
+{
+ ls->use_count++;
+ return ls;
+}
+
+/**
+ * Link a substream to a stream. The substream gains a reference, preventing
+ * it from being freed until it is unlinked.
+ **/
+void log_add_substream(struct log_stream *where, struct log_stream *what);
+
+/**
+ * Unlink all occurrences of a substream @what from stream @where. Each
+ * occurrence loses a reference. If @what is NULL, all substreams are unlinked.
+ * Returns the number of unlinked substreams.
+ **/
+int log_rm_substream(struct log_stream *where, struct log_stream *what);
+
+/**
+ * Set formatting flags of a given stream and all its substreams. The flags are
+ * AND'ed with @mask and OR'ed with @data.
+ **/
+void log_set_format(struct log_stream *ls, uint mask, uint data);
+
+/**
+ * Find a stream by its registration number (in the format of logging flags).
+ * Returns NULL if there is no such stream.
+ **/
+struct log_stream *log_stream_by_flags(uint flags);
+
+/** Return a pointer to the default stream (stream #0). **/
+static inline struct log_stream *log_default_stream(void)
+{
+ return log_stream_by_flags(0);
+}
+/**
+ * Make the specified stream the default destination.
+ *
+ * In fact, it takes the fixed default stream and attaches @ls as its only
+ * substream. If there were any other substreams, they are removed.
+ *
+ * Log streams created by <<basics:log_file()>> or @log_configured() are made default
+ * by calling this function.
+ **/
+void log_set_default_stream(struct log_stream *ls);
+
+/**
+ * Close all open streams, un-initialize the module, free all memory and
+ * reset the logging mechanism to use stderr only.
+ **/
+void log_close_all(void);
+
+/**
+ * The filter function of a stream might want to modify the message
+ * before passing it to the handler and/or substreams. In this case,
+ * the filter should make a local copy of `struct log_msg`, call
+ * @log_pass_filtered() on it and return true, so that the original
+ * message will not be processed any further.
+ **/
+void log_pass_filtered(struct log_stream *ls, struct log_msg *m);
+
+/***
+ * === Logging to files
+ *
+ * All log files are open in append mode, which guarantees atomicity of write()
+ * even in multi-threaded programs.
+ ***/
-/**** syslog */
+struct log_stream *log_new_file(const char *path, uint flags); /** Create a stream bound to a log file. See `FF_xxx` for @flags. **/
+struct log_stream *log_new_fd(int fd, uint flags); /** Create a stream bound to a file descriptor. See `FF_xxx` for @flags. **/
-// NOTE:
-// The syslog uses a bit different severity levels, for details, see
-// ls_syslog_convert_level().
-// syslog also prepends it's own time and severity info, so the default
-// messaging passes only clean message
+enum log_file_flag { /** Flags used for file-based logging **/
+ FF_FORMAT_NAME = 1, // Internal: Name contains strftime escapes
+ FF_CLOSE_FD = 2, // Close the fd with the stream (use with log_new_fd())
+ FF_FD2_FOLLOWS = 4, // Maintain stderr as a clone of this stream
+};
-/* assign log to a syslog facility */
-/* initialize with no formatting (syslog adds these inforamtion) */
-/* name is optional prefix (NULL for none) */
-struct log_stream *ls_syslog_new(int facility, const char *name);
+/**
+ * When a time-based name of the log file changes, the logger switches to a new
+ * log file automatically. This can be sometimes inconvenient, so you can use
+ * this function to disable the automatic switches. The calls to this function
+ * can be nested.
+ **/
+void log_switch_disable(void);
+void log_switch_enable(void); /** Negate the effect of log_switch_disable(). **/
+int log_switch(void); /** Switch log files manually. **/
+
+/***
+ * === Logging to syslog
+ *
+ * This log stream uses the libc interface to the system logging daemon (`syslogd`).
+ * This interface has several limitations:
+ *
+ * * Syslog are poorer than our scheme, so they are translated with a slight
+ * loss of information (most importantly, the distinction between local and
+ * remote messages is lost). If you are interested in details, search the
+ * source for syslog_level().
+ * * Syslog options (especially logging of PID with each message) must be fixed
+ * during initialization of the logger
+ * * Syslog provides its own formatting, so we turn off all formatting flags
+ * of the LibUCW logger. You can override this manually by setting the @msgfmt
+ * field of the log stream, but the result won't be nice.
+ * * Syslog does not support timestamps with sub-second precision.
+ ***/
+
+/**
+ * Create a log stream for logging to a selected syslog facility.
+ * The @options are passed to openlog(). (Beware, due to limitations of the
+ * syslog interface in libc, the @options are shared for all syslog streams
+ * and they are applied when the first stream is created.)
+ **/
+struct log_stream *log_new_syslog(const char *facility, int options);
+
+/**
+ * Verify that a facility of the given name exists. Return 1 if it does, 0 otherwise.
+ **/
+int log_syslog_facility_exists(const char *facility);
+
+/***
+ * === Configuring log streams
+ *
+ * If you use the LibUCW mechanism for parsing config files, you can let your
+ * user configure arbitrary log streams in the Logging section of the config file
+ * (see examples in the default config file). LibUCW automatically verifies that
+ * the configuration is consistent (this is performed in the commit hook of the
+ * config section), but it opens the streams only upon request. The following
+ * functions can be used to control that.
+ ***/
+
+/** Open a log stream configured under the specified name and increase its use count. **/
+struct log_stream *log_new_configured(const char *name);
+
+/** Open a log stream configured under the specified name and use it as the default destination. **/
+void log_configured(const char *name);
+
+/**
+ * Verify that a stream called @name was configured. If it wasn't, return an error
+ * message. This is intended to be used in configuration commit hooks.
+ **/
+char *log_check_configured(const char *name);
#endif
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