[PATCH RESEND 3/3] util/pty: fix a null pointer reference in qemu_openpty_raw

[Longpeng(Mike)]

From: Longpeng <longpe...@huawei.com>

q_ptsname may failed ane return null, so use the returned pointer
as the param of strcpy will cause null pointer deference. Use the
return string of openpty instead of call ptsname.

Signed-off-by: Longpeng <longpe...@huawei.com>
---
 util/qemu-openpty.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/util/qemu-openpty.c b/util/qemu-openpty.c
index 2e8b43b..2bea4ba 100644
--- a/util/qemu-openpty.c
+++ b/util/qemu-openpty.c
@@ -112,13 +112,7 @@ int qemu_openpty_raw(int *aslave, char *pty_name)
 {
     int amaster;
     struct termios tty;
-#if defined(__OpenBSD__) || defined(__DragonFly__)
-    char pty_buf[PATH_MAX];
-#define q_ptsname(x) pty_buf
-#else
-    char *pty_buf = NULL;
-#define q_ptsname(x) ptsname(x)
-#endif
+    char pty_buf[PATH_MAX] = { 0 };
 
     if (openpty(&amaster, aslave, pty_buf, NULL, NULL) < 0) {
         return -1;
@@ -130,7 +124,7 @@ int qemu_openpty_raw(int *aslave, char *pty_name)
     tcsetattr(*aslave, TCSAFLUSH, &tty);
 
     if (pty_name) {
-        strcpy(pty_name, q_ptsname(amaster));
+        strcpy(pty_name, pty_buf);
     }
 
     return amaster;
-- 
1.8.3.1