mingw: implement syslog

Syslog does not usually exist on Windows, so implement our own using
Window's ReportEvent mechanism.

Strings containing "%1" gets expanded into them selves by ReportEvent,
resulting in an unreadable string. "%2" and above is not a problem.
Unfortunately, on Windows an IPv6 address can contain "%1", so expand
"%1" to "% 1" before reporting. "%%1" is also a problem for ReportEvent,
but that string cannot occur in an IPv6 address.

Signed-off-by: Mike Pape <dotzenlabs@gmail.com>
Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -496,6 +496,7 @@ LIB_H += compat/bswap.h
 LIB_H += compat/cygwin.h
 LIB_H += compat/mingw.h
 LIB_H += compat/win32/pthread.h
+LIB_H += compat/win32/syslog.h
 LIB_H += csum-file.h
 LIB_H += decorate.h
 LIB_H += delta.h
@@ -1081,7 +1082,7 @@ ifeq ($(uname_S),Windows)
 	AR = compat/vcbuild/scripts/lib.pl
 	CFLAGS =
 	BASIC_CFLAGS = -nologo -I. -I../zlib -Icompat/vcbuild -Icompat/vcbuild/include -DWIN32 -D_CONSOLE -DHAVE_STRING_H -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_DEPRECATE
-	COMPAT_OBJS = compat/msvc.o compat/fnmatch/fnmatch.o compat/winansi.o compat/win32/pthread.o
+	COMPAT_OBJS = compat/msvc.o compat/fnmatch/fnmatch.o compat/winansi.o compat/win32/pthread.o compat/win32/syslog.o
 	COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DNOGDI -DHAVE_STRING_H -DHAVE_ALLOCA_H -Icompat -Icompat/fnmatch -Icompat/regex -Icompat/fnmatch -Icompat/win32 -DSTRIP_EXTENSION=\".exe\"
 	BASIC_LDFLAGS = -IGNORE:4217 -IGNORE:4049 -NOLOGO -SUBSYSTEM:CONSOLE -NODEFAULTLIB:MSVCRT.lib
 	EXTLIBS = advapi32.lib shell32.lib wininet.lib ws2_32.lib
@@ -1131,7 +1132,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/fnmatch -Icompat/win32
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
 	COMPAT_OBJS += compat/mingw.o compat/fnmatch/fnmatch.o compat/winansi.o \
-		compat/win32/pthread.o
+		compat/win32/pthread.o compat/win32/syslog.o
 	EXTLIBS += -lws2_32
 	PTHREAD_LIBS =
 	X = .exe

compat/win32/syslog.c

@@ -0,0 +1,72 @@
+#include "../../git-compat-util.h"
+#include "../../strbuf.h"
+
+static HANDLE ms_eventlog;
+
+void openlog(const char *ident, int logopt, int facility)
+{
+	if (ms_eventlog)
+		return;
+
+	ms_eventlog = RegisterEventSourceA(NULL, ident);
+
+	if (!ms_eventlog)
+		warning("RegisterEventSource() failed: %lu", GetLastError());
+}
+
+void syslog(int priority, const char *fmt, ...)
+{
+	struct strbuf sb = STRBUF_INIT;
+	struct strbuf_expand_dict_entry dict[] = {
+		{"1", "% 1"},
+		{NULL, NULL}
+	};
+	WORD logtype;
+	char *str;
+	int str_len;
+	va_list ap;
+
+	if (!ms_eventlog)
+		return;
+
+	va_start(ap, fmt);
+	str_len = vsnprintf(NULL, 0, fmt, ap);
+	va_end(ap);
+
+	if (str_len < 0) {
+		warning("vsnprintf failed: '%s'", strerror(errno));
+		return;
+	}
+
+	str = malloc(str_len + 1);
+	va_start(ap, fmt);
+	vsnprintf(str, str_len + 1, fmt, ap);
+	va_end(ap);
+	strbuf_expand(&sb, str, strbuf_expand_dict_cb, &dict);
+	free(str);
+
+	switch (priority) {
+	case LOG_EMERG:
+	case LOG_ALERT:
+	case LOG_CRIT:
+	case LOG_ERR:
+		logtype = EVENTLOG_ERROR_TYPE;
+		break;
+
+	case LOG_WARNING:
+		logtype = EVENTLOG_WARNING_TYPE;
+		break;
+
+	case LOG_NOTICE:
+	case LOG_INFO:
+	case LOG_DEBUG:
+	default:
+		logtype = EVENTLOG_INFORMATION_TYPE;
+		break;
+	}
+
+	ReportEventA(ms_eventlog, logtype, 0, 0, NULL, 1, 0,
+	    (const char **)&sb.buf, NULL);
+
+	strbuf_release(&sb);
+}

compat/win32/syslog.h

@@ -0,0 +1,20 @@
+#ifndef SYSLOG_H
+#define SYSLOG_H
+
+#define LOG_PID     0x01
+
+#define LOG_EMERG   0
+#define LOG_ALERT   1
+#define LOG_CRIT    2
+#define LOG_ERR     3
+#define LOG_WARNING 4
+#define LOG_NOTICE  5
+#define LOG_INFO    6
+#define LOG_DEBUG   7
+
+#define LOG_DAEMON  (3<<3)
+
+void openlog(const char *ident, int logopt, int facility);
+void syslog(int priority, const char *fmt, ...);
+
+#endif /* SYSLOG_H */

daemon.c

@@ -5,8 +5,6 @@
 #include "strbuf.h"
 #include "string-list.h"
 
-#include <syslog.h>
-
 #ifndef HOST_NAME_MAX
 #define HOST_NAME_MAX 256
 #endif

git-compat-util.h

@@ -104,6 +104,7 @@
 #include <assert.h>
 #include <regex.h>
 #include <utime.h>
+#include <syslog.h>
 #ifndef __MINGW32__
 #include <sys/wait.h>
 #include <sys/poll.h>