[Qemu-devel] [PATCH 1/3] qemu-bridge-helper: Reverse return value setting logic

[Michal Privoznik]

Instead of initializing the return value @ret to a success value
and then having to reset it to failure value in every error path,
we can do the opposite. Initialize the value to failure value and
then set it to success value only after we've succeeded in all
we've attempted.

Signed-off-by: Michal Privoznik <mpriv...@redhat.com>
---
 qemu-bridge-helper.c | 22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/qemu-bridge-helper.c b/qemu-bridge-helper.c
index 5396fbfbb6..af6613ea18 100644
--- a/qemu-bridge-helper.c
+++ b/qemu-bridge-helper.c
@@ -228,7 +228,7 @@ int main(int argc, char **argv)
     ACLRule *acl_rule;
     ACLList acl_list;
     int access_allowed, access_denied;
-    int ret = EXIT_SUCCESS;
+    int rv, ret = EXIT_FAILURE;
 
 #ifdef CONFIG_LIBCAP
     /* if we're run from an suid binary, immediately drop privileges preserving
@@ -265,7 +265,6 @@ int main(int argc, char **argv)
     if (parse_acl_file(DEFAULT_ACL_FILE, &acl_list) == -1) {
         fprintf(stderr, "failed to parse default acl file `%s'\n",
                 DEFAULT_ACL_FILE);
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -298,7 +297,6 @@ int main(int argc, char **argv)
 
     if ((access_allowed == 0) || (access_denied == 1)) {
         fprintf(stderr, "access denied by acl file\n");
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -306,7 +304,6 @@ int main(int argc, char **argv)
     ctlfd = socket(AF_INET, SOCK_STREAM, 0);
     if (ctlfd == -1) {
         fprintf(stderr, "failed to open control socket: %s\n", 
strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -314,7 +311,6 @@ int main(int argc, char **argv)
     fd = open("/dev/net/tun", O_RDWR);
     if (fd == -1) {
         fprintf(stderr, "failed to open /dev/net/tun: %s\n", strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -328,7 +324,6 @@ int main(int argc, char **argv)
 
     if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
         fprintf(stderr, "failed to create tun device: %s\n", strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -340,7 +335,6 @@ int main(int argc, char **argv)
     if (ioctl(ctlfd, SIOCGIFMTU, &ifr) == -1) {
         fprintf(stderr, "failed to get mtu of bridge `%s': %s\n",
                 bridge, strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -353,7 +347,6 @@ int main(int argc, char **argv)
     if (ioctl(ctlfd, SIOCSIFMTU, &ifr) == -1) {
         fprintf(stderr, "failed to set mtu of device `%s' to %d: %s\n",
                 iface, mtu, strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -364,14 +357,12 @@ int main(int argc, char **argv)
     if (ioctl(ctlfd, SIOCGIFHWADDR, &ifr) < 0) {
         fprintf(stderr, "failed to get MAC address of device `%s': %s\n",
                 iface, strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
     ifr.ifr_hwaddr.sa_data[0] = 0xFE;
     if (ioctl(ctlfd, SIOCSIFHWADDR, &ifr) < 0) {
         fprintf(stderr, "failed to set MAC address of device `%s': %s\n",
                 iface, strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -384,15 +375,14 @@ int main(int argc, char **argv)
     ifargs[2] = 0;
     ifargs[3] = 0;
     ifr.ifr_data = (void *)ifargs;
-    ret = ioctl(ctlfd, SIOCDEVPRIVATE, &ifr);
+    rv = ioctl(ctlfd, SIOCDEVPRIVATE, &ifr);
 #else
     ifr.ifr_ifindex = ifindex;
-    ret = ioctl(ctlfd, SIOCBRADDIF, &ifr);
+    rv = ioctl(ctlfd, SIOCBRADDIF, &ifr);
 #endif
-    if (ret == -1) {
+    if (rv == -1) {
         fprintf(stderr, "failed to add interface `%s' to bridge `%s': %s\n",
                 iface, bridge, strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -401,7 +391,6 @@ int main(int argc, char **argv)
     if (ioctl(ctlfd, SIOCGIFFLAGS, &ifr) == -1) {
         fprintf(stderr, "failed to get interface flags for `%s': %s\n",
                 iface, strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -409,7 +398,6 @@ int main(int argc, char **argv)
     if (ioctl(ctlfd, SIOCSIFFLAGS, &ifr) == -1) {
         fprintf(stderr, "failed to bring up interface `%s': %s\n",
                 iface, strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
@@ -417,13 +405,13 @@ int main(int argc, char **argv)
     if (send_fd(unixfd, fd) == -1) {
         fprintf(stderr, "failed to write fd to unix socket: %s\n",
                 strerror(errno));
-        ret = EXIT_FAILURE;
         goto cleanup;
     }
 
     /* ... */
 
     /* profit! */
+    ret = EXIT_SUCCESS;
 
 cleanup:
     if (fd >= 0) {
-- 
2.13.0