Logs: the error of opening a log returned, not passed in errno

On Windows proxy.h makes errno WSAGetLastError(), which cannot be
assigned, so the Windows build failed, and the error of fopen() would
not have been read there either. A type's init returns the errno value
(the C library's, read with _get_errno() on Windows), and logget() gives
it to its caller.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/conf.c

@@ -384,13 +384,14 @@ static int h_external(int argc, unsigned char ** argv){
 static int h_log(int argc, unsigned char ** argv){
 	struct logger *lg;
 	ROTATION rotation = (argc > 2)? getrotate(*argv[2]) : NONE;
+	int err = 0;
 
 	/* the same log as before is not opened again */
-	lg = logget((argc > 1)? argv[1] : (unsigned char *)"", rotation);
+	lg = logget((argc > 1)? argv[1] : (unsigned char *)"", rotation, &err);
 	if(!lg){
 		fprintf(stderr, "Unable to open log %.*s: %s, line %d\n",
 			(int)logselen((argc > 1)? argv[1] : (unsigned char *)""),
-			(argc > 1)? (char *)argv[1] : "", strerror(errno), linenum);
+			(argc > 1)? (char *)argv[1] : "", strerror(err), linenum);
 		return 1;
 	}
 	if(conf->stacksize < lg->type->stacksize) conf->stacksize = lg->type->stacksize;

src/log.c

@@ -508,19 +508,29 @@ static int matchfile(const unsigned char *selector){
 	return 1;
 }
 
+/* errno of the C library: on Windows proxy.h makes errno the socket error */
+#ifdef _WIN32
+static int crterrno(void){
+	int e = 0;
+
+	_get_errno(&e);
+	return e;
+}
+#else
+#define crterrno() (errno)
+#endif
+
 static int fileinit(struct logger *lg){
 	unsigned char *name;
-	FILE *fp;
-	int err;
+	FILE *fp = NULL;
+	int err = 0;
 
-	if(!(name = malloc(LOGNAMESIZE))) return 21;
+	if(!(name = malloc(LOGNAMESIZE))) return ENOMEM;
 	dologname(name, lg->selector, NULL, lg->rotation, lg->rotated);
-	errno = ENAMETOOLONG;
-	fp = *name? fopen((char *)name, "a") : NULL;
-	err = errno;
+	if(!*name) err = ENAMETOOLONG;
+	else if(!(fp = fopen((char *)name, "a")) && !(err = crterrno())) err = EIO;
 	free(name);
-	errno = err;
-	if(!fp) return 1;
+	if(err) return err;
 	lg->data = fp;
 	return 0;
 }
@@ -671,7 +681,7 @@ void loginit(void){
 #ifndef _WIN32
 	_3proxy_mutex_init(&syslog_mutex);
 	/* kept for the life of the process, as every syslog logger is */
-	(void)logget((const unsigned char *)"@3proxy", NONE);
+	(void)logget((const unsigned char *)"@3proxy", NONE, NULL);
 #endif
 }
 
@@ -701,9 +711,9 @@ static void logsetparams(struct logger *lg, const unsigned char *params){
 }
 
 /* The logger named so, opened if none is: held until logput(). NULL, with
-   errno set, if it cannot be opened. A logger found with other parameters
-   takes the new ones. */
-struct logger *logget(const unsigned char *selector, ROTATION rotation){
+   the error in *errp (an errno value) unless it is NULL, if it cannot be
+   opened. A logger found with other parameters takes the new ones. */
+struct logger *logget(const unsigned char *selector, ROTATION rotation, int *errp){
 	struct logger *lg;
 	const struct logtype *type;
 	const unsigned char *params;
@@ -730,7 +740,7 @@ struct logger *logget(const unsigned char *selector, ROTATION rotation){
 			free(lg);
 		}
 		_3proxy_mutex_unlock(&log_mutex);
-		errno = ENOMEM;
+		if(errp) *errp = ENOMEM;
 		return NULL;
 	}
 	memcpy(lg->selector, selector, len);
@@ -745,13 +755,12 @@ struct logger *logget(const unsigned char *selector, ROTATION rotation){
 		lg->failtime = lg->rotated;
 	}
 	else if(err){
-		err = errno;
 		_3proxy_mutex_unlock(&log_mutex);
 		_3proxy_mutex_destroy(&lg->mutex);
 		if(lg->params) free(lg->params);
 		free(lg->selector);
 		free(lg);
-		errno = err;
+		if(errp) *errp = err;
 		return NULL;
 	}
 	lg->refs = 1;

src/mainconf.c

@@ -318,12 +318,13 @@ static int srvprepare(struct srvstart *s, int argc, char **argv){
 		 case 'l':
 			{
 				struct logger *lg;
+				int err = 0;
 
 				/* the same log the log command, or another service,
 				   opened is shared with it */
-				if(!(lg = logget((unsigned char *)argv[i] + 2, NONE))){
+				if(!(lg = logget((unsigned char *)argv[i] + 2, NONE, &err))){
 					fprintf(stderr, "Unable to open log %.*s: %s\n",
-						(int)logselen((unsigned char *)argv[i] + 2), argv[i] + 2, strerror(errno));
+						(int)logselen((unsigned char *)argv[i] + 2), argv[i] + 2, strerror(err));
 					return 1;
 				}
 				logput(srv->logger);

src/proxy.h

@@ -346,7 +346,7 @@ void logdo(struct clientparam * param, const unsigned char *s);
 void logerror(const unsigned char *s);
 void loginit(void);
 void logtypeadd(const struct logtype *type);
-struct logger *logget(const unsigned char *selector, ROTATION rotation);
+struct logger *logget(const unsigned char *selector, ROTATION rotation, int *errp);
 void logref(struct logger *lg);
 void logput(struct logger *lg);
 void logcommit(struct extparam *c);

src/sql.c

@@ -101,7 +101,7 @@ static int odbcmatch(const unsigned char *selector){
 /* A data source down is not an error of the configuration: the log
    connects again later. */
 static int odbcinit(struct logger *lg){
-    if(!lg->data && !(lg->data = calloc(1, sizeof(struct logodbc)))) return 21;
+    if(!lg->data && !(lg->data = calloc(1, sizeof(struct logodbc)))) return ENOMEM;
     return odbcconnect(lg)? 0 : -1;
 }
 

src/structures.h

@@ -635,8 +635,8 @@ struct hashtable {
 struct logtype {
 	const char *name;
 	int (*match)(const unsigned char *selector);
-	/* opens what it writes to, lg->data: 0, an error, or < 0 if it cannot
-	   be reached now but is to be tried again */
+	/* opens what it writes to, lg->data: 0, an error (an errno value), or
+	   < 0 if it cannot be reached now but is to be tried again */
 	int (*init)(struct logger *lg);
 	/* the line for a connection into buf, CLIENTTMPBUFSIZE: its length, -1
 	   for nothing to write; NULL if write() takes the connection itself */