log.c: Added basic logging support.

src/log.c

@@ -0,0 +1,160 @@
+/* log.c
+ *
+ *   Copyright (C) 2010   Henrik Hautakoski <henrik@fiktivkod.org>
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ */
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include "strbuf.h"
+#include "log.h"
+
+static FILE *logfd = NULL;
+static char *file = NULL;
+static char *logname = NULL;
+
+static struct {
+    const char *name;
+    unsigned mask;
+} levels[] = {
+    { "INFO",     LOG_INFO  },
+    { "WARNING",  LOG_WARN  },
+    { "CRITICAL", LOG_CRIT  },
+    { "DEBUG",    LOG_DEBUG },
+    { NULL,       0         }
+};
+
+static int mask = 0;
+
+/* check (and change) if we need to roll logging file */
+static void checklog() {
+
+    if (file) {
+        time_t t;
+        char name[15];
+
+        time(&t);
+        strftime(name, sizeof(name), "%Y-%m-%d.log", localtime(&t));
+
+        /* update the name if we have changed date */
+        if (strncmp(logname, name, sizeof(name))) {
+            memcpy(logname, name, sizeof(name));
+
+            if (logfd && logfd != stderr)
+                fclose(logfd);
+            logfd = fopen(file, "a");
+        }
+    }
+
+    if (!logfd)
+        logfd = stderr;
+}
+
+/* writes the information about a logg message (timestamp and level) */
+static void writeinfo(unsigned level) {
+
+    time_t tnow;
+    char buf[512], *ptr;
+
+    time(&tnow);
+    ptr = buf + strftime(buf, sizeof(buf), "[%H:%M:%S] ", localtime(&tnow));
+    ptr += sprintf(ptr, "%-10s ", loglvltostr(level));
+
+    fputs(buf, logfd);
+}
+
+static int validmask(unsigned x, char unique) {
+
+    /* check if only one bit is set */
+    if (unique && (x & (x - 1)) != 0)
+        return 0;
+
+    /* make sure we don't have any unused bits */
+    return (x & ~LOG_ALL) == 0;
+}
+
+void init_log(unsigned level, const char *path) {
+
+    if (!validmask(level, 0))
+        die("init_log: unknown level: %x\n", level);
+
+    mask = level;
+
+    if (path) {
+        strbuf_t sb = STRBUF_INIT;
+        size_t nameoffset;
+
+        strbuf_append_str(&sb, path);
+        strbuf_term(&sb, '/');
+        nameoffset = sb.len;
+
+        strbuf_append_repeat(&sb, 0, 14);
+
+        if (file)
+            xfree(file);
+
+        file = strbuf_release(&sb);
+        logname = file + nameoffset;
+    } else {
+        logname = file = NULL;
+    }
+}
+
+const char* loglvltostr(unsigned level) {
+
+    int i;
+
+    for(i=0; levels[i].name; i++) {
+
+        if (level & levels[i].mask)
+            return levels[i].name;
+    }
+    return "UNKNOWN";
+}
+
+void logmsg(unsigned level, const char *fmt, ...) {
+
+	va_list vl;
+    FILE *fd;
+
+    if (!validmask(level, 1))
+        die("log: invalid level: %x\n", level);
+
+    if (level & ~mask)
+        return;
+
+    checklog();
+    writeinfo(level);
+    va_start(vl, fmt);
+    vfprintf(logfd, fmt, vl);
+    va_end(vl);
+    fputc('\n', logfd);
+    fflush(logfd);
+}
+
+void logerrno(unsigned level, const char *prefix, int err) {
+
+	char *str = strerror(err);
+    
+	if (str && level & mask) {
+
+        if (!validmask(level, 1))
+            die("logerrno: invalid level: %x\n", level);
+
+        checklog();
+        writeinfo(level);
+        if (prefix && *prefix)
+            fprintf(logfd, "%s: ", prefix);
+        fputs(str, logfd);
+        fputc('\n', logfd);
+        fflush(logfd);
+	}
+}

src/log.h

@@ -0,0 +1,30 @@
+/* log.h
+ *
+ *   Copyright (C) 2010   Henrik Hautakoski <henrik@fiktivkod.org>
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ */
+#ifndef __LOG_H
+#define __LOG_H
+
+#include <stdarg.h>
+#include <stddef.h>
+
+#define LOG_INFO  (1<<0)
+#define LOG_WARN  (1<<1) 
+#define LOG_CRIT  (1<<2)
+#define LOG_DEBUG (1<<3)
+#define LOG_ALL   (LOG_INFO | LOG_WARN | LOG_CRIT | LOG_DEBUG)
+
+void init_log(unsigned level, const char *path);
+
+const char* loglvltostr(unsigned level);
+
+void logmsg(unsigned level, const char *fmt, ...);
+
+void logerrno(unsigned level, const char *prefix, int err);
+
+#endif /* __LOG_H */

test/Makefile

@@ -1,6 +1,6 @@
 # Test makefile
 CC=gcc
-CFLAGS=-g -D__DEBUG__ 
+CFLAGS=-g -D__DEBUG__
 LDFLAGS=-L/usr/lib64/mysql -lmysqlclient
 
 all : raw_inotify strbuf path rbtree inotify fscrawl queue
@@ -57,5 +57,8 @@ fscrawl :
 queue :
 	$(CC) $(CFLAGS) ../src/queue.c t_queue.c -o test_queue
 
+log :
+	$(CC) $(CFLAGS) ../src/die.c ../src/strbuf.c ../src/xalloc.c ../src/log.c t_log.c -o test_log
+
 clean :
 	rm -f test_*

test/t_log.c

@@ -0,0 +1,28 @@
+
+#include <errno.h>
+#include <stddef.h>
+#include "../src/log.h"
+
+int main() {
+
+    init_log(LOG_INFO | LOG_WARN, NULL);
+
+    logmsg(LOG_INFO, "this is stderr");
+
+    logmsg(LOG_CRIT, "Should not show");
+    logerrno(LOG_CRIT, NULL, ENOENT);
+
+    init_log(LOG_INFO | LOG_WARN | LOG_CRIT, "./logs/");
+
+    logmsg(LOG_INFO, "some info");
+    logmsg(LOG_WARN, "invalid type '%i'", 3);
+
+    logerrno(LOG_CRIT, "malloc", ENOMEM);
+    logerrno(LOG_CRIT, NULL, ENOENT);
+    
+    logmsg(LOG_DEBUG, "Should not show");
+
+    logmsg(LOG_INFO | LOG_CRIT, "Should not work, can only log to one priority");
+
+    return 0;
+}