util: add virVasprintf

* src/util/util.h (virVasprintf): New declaration.
* src/util/util.c (virVasprintf): New function.
(virAsprintf): Use it.
* src/util/virtaudit.c (virAuditSend): Likewise.
* src/libvirt_private.syms: Export it.
* cfg.mk (sc_prohibit_asprintf): Also prohibit vasprintf.
* .x-sc_prohibit_asprintf: Add exemption.

.x-sc_prohibit_asprintf

+ChangeLog
+^bootstrap.conf$
 ^gnulib/
 ^po/
-ChangeLog
+^src/util/util.c$

cfg.mk

@@ -255,7 +255,7 @@ sc_prohibit_strncmp:
 
 # Use virAsprintf rather than as'printf since *strp is undefined on error.
 sc_prohibit_asprintf:
-	@prohibit='\<a[s]printf\>'					\
+	@prohibit='\<v?a[s]printf\>'					\
 	halt='use virAsprintf, not as'printf				\
 	  $(_sc_search_regexp)
 

src/libvirt_private.syms

@@ -817,6 +817,7 @@ virStrToLong_ull;
 virStrcpy;
 virStrncpy;
 virTimestamp;
+virVasprintf;
 
 
 # uuid.h

src/util/util.c

@@ -2198,6 +2198,22 @@ virParseVersionString(const char *str, unsigned long *version)
     return 0;
 }
 
+/**
+ * virVasprintf
+ *
+ * like glibc's vasprintf but makes sure *strp == NULL on failure
+ */
+int
+virVasprintf(char **strp, const char *fmt, va_list list)
+{
+    int ret;
+
+    if ((ret = vasprintf(strp, fmt, list)) == -1)
+        *strp = NULL;
+
+    return ret;
+}
+
 /**
  * virAsprintf
  *
@@ -2210,10 +2226,7 @@ virAsprintf(char **strp, const char *fmt, ...)
     int ret;
 
     va_start(ap, fmt);
-
-    if ((ret = vasprintf(strp, fmt, ap)) == -1)
-        *strp = NULL;
-
+    ret = virVasprintf(strp, fmt, ap);
     va_end(ap);
     return ret;
 }

src/util/util.h

@@ -31,6 +31,7 @@
 # include <unistd.h>
 # include <sys/select.h>
 # include <sys/types.h>
+# include <stdarg.h>
 
 # ifndef MIN
 #  define MIN(a, b) ((a) < (b) ? (a) : (b))
@@ -202,7 +203,10 @@ int virMacAddrCompare (const char *mac1, const char *mac2);
 void virSkipSpaces(const char **str);
 int virParseNumber(const char **str);
 int virParseVersionString(const char *str, unsigned long *version);
-int virAsprintf(char **strp, const char *fmt, ...) ATTRIBUTE_FMT_PRINTF(2, 3);
+int virAsprintf(char **strp, const char *fmt, ...)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_FMT_PRINTF(2, 3);
+int virVasprintf(char **strp, const char *fmt, va_list list)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_FMT_PRINTF(2, 0);
 char *virStrncpy(char *dest, const char *src, size_t n, size_t destbytes)
     ATTRIBUTE_RETURN_CHECK;
 char *virStrcpy(char *dest, const char *src, size_t destbytes)

src/util/virtaudit.c

@@ -95,7 +95,7 @@ void virAuditSend(const char *file ATTRIBUTE_UNUSED, const char *func,
 #endif
 
     va_start(args, fmt);
-    if (vasprintf(&str, fmt, args) < 0) {
+    if (virVasprintf(&str, fmt, args) < 0) {
         VIR_WARN0("Out of memory while formatting audit message");
         str = NULL;
     }