lib/log: add spdk_vlog function

Some users of SPDK API, such as OCF,
may want to generate logs with arguments themselves.
In that case they would need to first create a buffer
and then pass that buffer as a single argument to spdk_log().
This change adds spdk_vlog() which accepts va_list as argument list,
so it is easier to use spdk_log().

Change-Id: Ie2a3ac481035a250fcd68d0f9b8292008ebb6fe0
Signed-off-by: Vitaliy Mysak <vitaliy.mysak@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/1946
Community-CI: Mellanox Build Bot
Community-CI: Broadcom CI
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

include/spdk/log.h

@@ -154,6 +154,20 @@ enum spdk_log_level spdk_log_get_print_level(void);
 void spdk_log(enum spdk_log_level level, const char *file, const int line, const char *func,
 	      const char *format, ...) __attribute__((__format__(__printf__, 5, 6)));
 
+/**
+ * Same as spdk_log except that instead of being called with variable number of
+ * arguments it is called with an argument list as defined in stdarg.h
+ *
+ * \param level Log level threshold.
+ * \param file Name of the current source file.
+ * \param line Current source line number.
+ * \param func Current source function name.
+ * \param format Format string to the message.
+ * \param ap printf arguments
+ */
+void spdk_vlog(enum spdk_log_level level, const char *file, const int line, const char *func,
+	       const char *format, va_list ap);
+
 /**
  * Log the contents of a raw buffer to a file.
  *

lib/log/Makefile

@@ -35,7 +35,7 @@ SPDK_ROOT_DIR := $(abspath $(CURDIR)/../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
 SO_VER := 2
-SO_MINOR := 0
+SO_MINOR := 1
 SO_SUFFIX := $(SO_VER).$(SO_MINOR)
 
 C_SRCS = log.c log_flags.c

lib/log/log.c

@@ -127,16 +127,24 @@ get_timestamp_prefix(char *buf, int buf_size)
 void
 spdk_log(enum spdk_log_level level, const char *file, const int line, const char *func,
 	 const char *format, ...)
+{
+	va_list ap;
+
+	va_start(ap, format);
+	spdk_vlog(level, file, line, func, format, ap);
+	va_end(ap);
+}
+
+void
+spdk_vlog(enum spdk_log_level level, const char *file, const int line, const char *func,
+	  const char *format, va_list ap)
 {
 	int severity = LOG_INFO;
 	char buf[MAX_TMPBUF];
 	char timestamp[32];
-	va_list ap;
 
 	if (g_log) {
-		va_start(ap, format);
 		g_log(level, file, line, func, format, ap);
-		va_end(ap);
 		return;
 	}
 
@@ -162,8 +170,6 @@ spdk_log(enum spdk_log_level level, const char *file, const int line, const char
 		return;
 	}
 
-	va_start(ap, format);
-
 	vsnprintf(buf, sizeof(buf), format, ap);
 
 	if (level <= g_spdk_log_print_level) {
@@ -183,8 +189,6 @@ spdk_log(enum spdk_log_level level, const char *file, const int line, const char
 			syslog(severity, "%s", buf);
 		}
 	}
-
-	va_end(ap);
 }
 
 static void

lib/log/spdk_log.map

@@ -11,6 +11,7 @@
 	spdk_log_set_print_level;
 	spdk_log_get_print_level;
 	spdk_log;
+	spdk_vlog;
 	spdk_log_dump;
 	spdk_log_get_flag;
 	spdk_log_set_flag;