qemu-char: Plug memory leak on qemu_chr_open_pty() error path

Spotted by Coverity.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

qemu-char.c

@@ -985,7 +985,7 @@ static int qemu_chr_open_pty(QemuOpts *opts, CharDriverState **_chr)
     CharDriverState *chr;
     PtyCharDriver *s;
     struct termios tty;
-    int slave_fd, len;
+    int master_fd, slave_fd, len;
 #if defined(__OpenBSD__) || defined(__DragonFly__)
     char pty_name[PATH_MAX];
 #define q_ptsname(x) pty_name
@@ -994,10 +994,7 @@ static int qemu_chr_open_pty(QemuOpts *opts, CharDriverState **_chr)
 #define q_ptsname(x) ptsname(x)
 #endif
 
-    chr = g_malloc0(sizeof(CharDriverState));
-    s = g_malloc0(sizeof(PtyCharDriver));
-
-    if (openpty(&s->fd, &slave_fd, pty_name, NULL, NULL) < 0) {
+    if (openpty(&master_fd, &slave_fd, pty_name, NULL, NULL) < 0) {
         return -errno;
     }
 
@@ -1007,17 +1004,21 @@ static int qemu_chr_open_pty(QemuOpts *opts, CharDriverState **_chr)
     tcsetattr(slave_fd, TCSAFLUSH, &tty);
     close(slave_fd);
 
-    len = strlen(q_ptsname(s->fd)) + 5;
+    chr = g_malloc0(sizeof(CharDriverState));
+
+    len = strlen(q_ptsname(master_fd)) + 5;
     chr->filename = g_malloc(len);
-    snprintf(chr->filename, len, "pty:%s", q_ptsname(s->fd));
-    qemu_opt_set(opts, "path", q_ptsname(s->fd));
-    fprintf(stderr, "char device redirected to %s\n", q_ptsname(s->fd));
+    snprintf(chr->filename, len, "pty:%s", q_ptsname(master_fd));
+    qemu_opt_set(opts, "path", q_ptsname(master_fd));
+    fprintf(stderr, "char device redirected to %s\n", q_ptsname(master_fd));
 
+    s = g_malloc0(sizeof(PtyCharDriver));
     chr->opaque = s;
     chr->chr_write = pty_chr_write;
     chr->chr_update_read_handler = pty_chr_update_read_handler;
     chr->chr_close = pty_chr_close;
 
+    s->fd = master_fd;
     s->timer = qemu_new_timer_ms(rt_clock, pty_chr_timer, chr);
 
     *_chr = chr;