xenstore: Do not assign to stdout/stderr/stdin - they are not

implemented as variables on all systems.
Signed-off-by: Keir Fraser <keir@xensource.com>

3 files changed, 5 insertions, 10 deletions

diff --git a/tools/xenstore/utils.c b/tools/xenstore/utils.c
index d7f5219a87..a1ac12584a 100644
--- a/tools/xenstore/utils.c
+++ b/tools/xenstore/utils.c
@@ -10,19 +10,18 @@
 #include <signal.h>
 #include "utils.h"
 
-void xprintf(const char *fmt, ...)
+static void default_xprintf(const char *fmt, ...)
 {
 	va_list args;
 
-	if (!stderr)
-		return; /* could trace()? */
-
 	va_start(args, fmt);
 	vfprintf(stderr, fmt, args);
 	va_end(args);
 	fflush(stderr);
 }
 
+void (*xprintf)(const char *fmt, ...) = default_xprintf;
+
 void barf(const char *fmt, ...)
 {
 	char *str;
diff --git a/tools/xenstore/utils.h b/tools/xenstore/utils.h
index ce14f3a408..f378343707 100644
--- a/tools/xenstore/utils.h
+++ b/tools/xenstore/utils.h
@@ -24,7 +24,7 @@ static inline bool strends(const char *a, const char *b)
 void barf(const char *fmt, ...) __attribute__((noreturn));
 void barf_perror(const char *fmt, ...) __attribute__((noreturn));
 
-void xprintf(const char *fmt, ...);
+void (*xprintf)(const char *fmt, ...);
 
 #define eprintf(_fmt, _args...) xprintf("[ERR] %s" _fmt, __FUNCTION__, ##_args)
 
diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c
index fc3171f14b..a969bcff56 100644
--- a/tools/xenstore/xenstored_core.c
+++ b/tools/xenstore/xenstored_core.c
@@ -1883,11 +1883,7 @@ int main(int argc, char *argv[])
 		close(STDIN_FILENO);
 		close(STDOUT_FILENO);
 		close(STDERR_FILENO);
-
-		/* Get ourselves a nice xenstored crash if these are used. */
-		stdin = NULL;
-		stdout = NULL;
-		stderr = NULL;
+		xprintf = trace; /* xprintf() must not use stderr */
 	}
 
 	signal(SIGHUP, trigger_reopen_log);