From: Roy Marples <roy@marples.name>
Date: Tue, 11 Apr 2017 17:04:03 +0000 (+0100)
Subject: Write syslog entries in logfile:
X-Git-Tag: v7.0.0-beta3~25
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=12cc2d99466df9f11602983009ee43ee3414304d;p=thirdparty%2Fdhcpcd.git

Write syslog entries in logfile:
  date tag[pid]: message
This does add a few more bytes, but it allows for the same log
analysis tools to be used.
When building SMALL, this code is removed and you just get the
message in the logfile.
---

diff --git a/BUILDING.md b/BUILDING.md
index a944417a..f1574241 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -11,7 +11,7 @@ To compile small dhcpcd, maybe to be used for installation media where
 size is a concern, you can use the `--small` configure option to enable
 a reduced feature set within dhcpcd.
 Currently this just removes non important options out of
-`dhcpcd-definitions.conf`, the custom logger and
+`dhcpcd-definitions.conf`, the logfile option and
 support for DHCPv6 Prefix Delegation.
 Other features maybe dropped as and when required.
 dhcpcd can also be made smaller by removing the IPv4 or IPv6 stack:
diff --git a/src/dhcpcd.c b/src/dhcpcd.c
index e7822dde..e9fbcc50 100644
--- a/src/dhcpcd.c
+++ b/src/dhcpcd.c
@@ -1461,7 +1461,8 @@ main(int argc, char **argv)
 #ifdef INET
 	ctx.udp_fd = -1;
 #endif
-	logopts = LOGERR_WLOG;
+	/* syslog style logging */
+	logopts = LOGERR_LOG|LOGERR_LOG_DATE|LOGERR_LOG_TAG|LOGERR_LOG_PID;
 	i = 0;
 	while ((opt = getopt_long(argc, argv,
 	    ctx.options & DHCPCD_PRINT_PIDFILE ? NOERR_IF_OPTS : IF_OPTS,
@@ -1513,7 +1514,7 @@ main(int argc, char **argv)
 			break;
 		case 'T':
 			i = 1;
-			logopts &= ~LOGERR_WLOG;
+			logopts &= ~LOGERR_LOG;
 			break;
 		case 'U':
 			i = 3;
diff --git a/src/logerr.c b/src/logerr.c
index ee97624a..2ae7ce37 100644
--- a/src/logerr.c
+++ b/src/logerr.c
@@ -27,35 +27,88 @@
 
 #include <sys/time.h>
 #include <errno.h>
+#include <stdbool.h>
 #include <stdarg.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <syslog.h>
 #include <time.h>
+#include <unistd.h>
 
 #include "logerr.h"
 
 #ifndef	LOGERR_SYSLOG_FACILITY
 #define	LOGERR_SYSLOG_FACILITY	LOG_DAEMON
 #endif
-#ifndef	LOGERR_SYSLOG_OPTS
-#define	LOGERR_SYSLOG_OPTS	LOG_PID
-#endif
+
+#define UNUSED(a)		(void)(a)
 
 struct logctx {
 	unsigned int	 log_opts;
+#ifndef SMALL
+	const char	*log_tag;
 	FILE		*log_file;
+#endif
 };
 
 static struct logctx _logctx = {
-	.log_opts = LOGERR_WLOG,
-	.log_file = NULL,
+	/* syslog style by default */
+	.log_opts = LOGERR_LOG | LOGERR_LOG_DATE |
+	            LOGERR_LOG_TAG | LOGERR_LOG_PID,
 };
 
-__printflike(2, 0) static void
-vlogprintf(FILE *stream, const char *fmt, va_list args)
+#if !defined(SMALL) && defined(__linux__)
+/* Poor man's getprogname(3). */
+static char *_logprog;
+static const char *
+getprogname(void)
+{
+	const char *p;
+
+	/* Use PATH_MAX + 1 to avoid truncation. */
+	if (_logprog == NULL) {
+		/* readlink(2) does not append a NULL byte,
+		 * so zero the buffer. */
+		if ((_logprog = calloc(1, PATH_MAX + 1)) == NULL)
+			return NULL;
+	}
+	if (readlink("/proc/self/exe", _logprog, PATH_MAX + 1) == -1)
+		return NULL;
+	if (_logprog[0] == '[')
+		return NULL;
+	p = strrchr(_logprog, '/');
+	if (p == NULL)
+		return _logprog;
+	return p + 1;
+}
+#endif
+
+__printflike(3, 0) static void
+vlogprintf_r(struct logctx *ctx, FILE *stream, const char *fmt, va_list args)
 {
 	va_list a;
+#ifndef SMALL
+	bool log_tag, log_pid;
+
+	log_tag = ((stream == stderr && ctx->log_opts & LOGERR_ERR_TAG) ||
+	    (stream != stderr && ctx->log_opts & LOGERR_LOG_TAG));
+	if (log_tag) {
+		if (ctx->log_tag == NULL)
+			ctx->log_tag = getprogname();
+		fprintf(stream, "%s", ctx->log_tag);
+	}
+
+	log_pid = ((stream == stderr && ctx->log_opts & LOGERR_ERR_PID) ||
+	    (stream != stderr && ctx->log_opts & LOGERR_LOG_PID));
+	if (log_pid)
+		fprintf(stream, "[%d]", getpid());
+
+	if (log_tag || log_pid)
+		fprintf(stream, ": ");
+#else
+	UNUSED(ctx);
+#endif
 
 	va_copy(a, args);
 	vfprintf(stream, fmt, a);
@@ -81,37 +134,45 @@ vlogprintf(FILE *stream, const char *fmt, va_list args)
 __printflike(2, 0) static void
 vlogmessage(int pri, const char *fmt, va_list args)
 {
+#ifndef SMALL
+	struct timeval tv;
+#endif
+	struct logctx *ctx = &_logctx;
 
 	if (pri <= LOG_ERR ||
-	    (!(_logctx.log_opts & LOGERR_QUIET) && pri <= LOG_INFO) ||
-	    (_logctx.log_opts & LOGERR_DEBUG && pri <= LOG_DEBUG))
-		vlogprintf(stderr, fmt, args);
+	    (!(ctx->log_opts & LOGERR_QUIET) && pri <= LOG_INFO) ||
+	    (ctx->log_opts & LOGERR_DEBUG && pri <= LOG_DEBUG))
+		vlogprintf_r(ctx, stderr, fmt, args);
 
-	if (!(_logctx.log_opts & LOGERR_WLOG))
+	if (!(ctx->log_opts & LOGERR_LOG))
 		return;
 
-	if (_logctx.log_file != NULL) {
-		struct timeval tv;
-
-		if (pri == LOG_DEBUG && !(_logctx.log_opts & LOGERR_DEBUG))
-			return;
+#ifdef SMALL
+	vsyslog(pri, fmt, args);
+#else
+	if (ctx->log_file == NULL) {
+		vsyslog(pri, fmt, args);
+		return;
+	}
 
-		/* Write the time, syslog style. month day time - */
-		if (gettimeofday(&tv, NULL) != -1) {
-			time_t now;
-			struct tm tmnow;
-			char buf[32];
+	if (pri == LOG_DEBUG && !(ctx->log_opts & LOGERR_DEBUG))
+		return;
 
-			now = tv.tv_sec;
-			tzset();
-			localtime_r(&now, &tmnow);
-			strftime(buf, sizeof(buf), "%b %d %T ", &tmnow);
-			fprintf(_logctx.log_file, "%s", buf);
-		}
+	/* Write the time, syslog style. month day time - */
+	if (ctx->log_opts & LOGERR_LOG_DATE && gettimeofday(&tv, NULL) != -1) {
+		time_t now;
+		struct tm tmnow;
+		char buf[32];
+
+		now = tv.tv_sec;
+		tzset();
+		localtime_r(&now, &tmnow);
+		strftime(buf, sizeof(buf), "%b %d %T ", &tmnow);
+		fprintf(ctx->log_file, "%s", buf);
+	}
 
-		vlogprintf(_logctx.log_file, fmt, args);
-	} else
-		vsyslog(pri, fmt, args);
+	vlogprintf_r(ctx, ctx->log_file, fmt, args);
+#endif
 }
 #if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ > 5))
 #pragma GCC diagnostic pop
@@ -200,33 +261,64 @@ logerrx(const char *fmt, ...)
 void
 logsetopts(unsigned int opts)
 {
+	struct logctx *ctx = &_logctx;
 
-	_logctx.log_opts = opts;
+	ctx->log_opts = opts;
 	setlogmask(LOG_UPTO(opts & LOGERR_DEBUG ? LOG_DEBUG : LOG_INFO));
 }
 
+void
+logsettag(const char *tag)
+{
+#ifndef SMALL
+	struct logctx *ctx = &_logctx;
+
+	ctx->log_tag = tag;
+#else
+	UNUSED(tag);
+#endif
+}
+
 int
 logopen(const char *path)
 {
+	struct logctx *ctx = &_logctx;
 
 	if (path == NULL) {
-		openlog(NULL, LOGERR_SYSLOG_OPTS, LOGERR_SYSLOG_FACILITY);
+		int opts = 0;
+
+		if (ctx->log_opts & LOGERR_LOG_PID)
+			opts |= LOG_PID;
+		openlog(NULL, opts, LOGERR_SYSLOG_FACILITY);
 		return 1;
 	}
 
-	if ((_logctx.log_file = fopen(path, "w")) == NULL)
+#ifndef SMALL
+	if ((ctx->log_file = fopen(path, "w")) == NULL)
 		return -1;
-	setlinebuf(_logctx.log_file);
-	return fileno(_logctx.log_file);
+	setlinebuf(ctx->log_file);
+	return fileno(ctx->log_file);
+#else
+	errno = ENOTSUP;
+	return -1;
+#endif
 }
 
 void
 logclose(void)
 {
+#ifndef SMALL
+	struct logctx *ctx = &_logctx;
+#endif
 
 	closelog();
-	if (_logctx.log_file == NULL)
+#ifndef SMALL
+	if (ctx->log_file == NULL)
 		return;
-	fclose(_logctx.log_file);
-	_logctx.log_file = NULL;
+	fclose(ctx->log_file);
+	ctx->log_file = NULL;
+#endif
+#if !defined(SMALL) && defined(__linux__)
+	free(_logprog);
+#endif
 }
diff --git a/src/logerr.h b/src/logerr.h
index 5b928ffd..b9a8fbc5 100644
--- a/src/logerr.h
+++ b/src/logerr.h
@@ -49,9 +49,15 @@ __printflike(1, 2) void logerr(const char *, ...);
 __printflike(1, 2) void logerrx(const char *, ...);
 
 void logsetopts(unsigned int);
-#define	LOGERR_WLOG	(1U << 1)
-#define	LOGERR_DEBUG	(1U << 2)
-#define	LOGERR_QUIET	(1U << 3)
+#define	LOGERR_LOG	(1U <<  1)
+#define	LOGERR_LOG_TAG	(1U <<  2)
+#define	LOGERR_LOG_PID	(1U <<  3)
+#define	LOGERR_LOG_DATE	(1U <<  4)
+#define	LOGERR_ERR_TAG	(1U << 11)
+#define	LOGERR_ERR_PID	(1U << 12)
+#define	LOGERR_DEBUG	(1U << 21)
+#define	LOGERR_QUIET	(1U << 22)
+void logsettag(const char *);
 
 int logopen(const char *);
 void logclose(void);