Use va_copy when we use va_list twice

When tracing (if the DEBUG compile-time option was set to 1 or 2), exverror calls TRACEV to print its arguments before passing them on to exvwarning. That consumes the arguments, resulting in a segfault:

 $ sh -c '"'
 sh: Syntax error: Unterminated quoted string
 $ sh -o debug -c '"'
 sh: Segmentation fault (core dumped)

Making a copy with va_copy fixes it.

---
Ran into this while tracking down a potential ifs leak from
<http://bugs.debian.org/618023>.

 src/error.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

index f1a358d..e51d827 100644
@@ -143,8 +143,10 @@ exverror(int cond, const char *msg, va_list ap)
 {
 #ifdef DEBUG
 	if (msg) {
+		va_list aq;
+		va_copy(aq, ap);
 		TRACE(("exverror(%d, \"", cond));
-		TRACEV((msg, ap));
+		TRACEV((msg, aq));
 		TRACE(("\") pid=%d\n", getpid()));
 	} else
 		TRACE(("exverror(%d, NULL) pid=%d\n", cond, getpid()));

1.7.4.1

When tracing (with the DEBUG compile-time option set to 1 or 2), exverror calls TRACEV to print its arguments before passing them on. So the arguments are consumed by the time exvwarning looks for them, resulting in a segfault:

 $ sh -c '"'
 sh: Syntax error: Unterminated quoted string
 $ sh -o debug -c '"'
 sh: Segmentation fault (core dumped)

Make a copy with va_copy to avoid this.

---
v1 left out va_end. Sorry for the nonsense.

 src/error.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

index f1a358d..db2eb62 100644
@@ -143,8 +143,11 @@ exverror(int cond, const char *msg, va_list ap)
 {
 #ifdef DEBUG
 	if (msg) {
+		va_list aq;
 		TRACE(("exverror(%d, \"", cond));
-		TRACEV((msg, ap));
+		va_copy(aq, ap);
+		TRACEV((msg, aq));
+		va_end(aq);
 		TRACE(("\") pid=%d\n", getpid()));
 	} else
 		TRACE(("exverror(%d, NULL) pid=%d\n", cond, getpid()));

1.7.4.1

Also applied.

Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt