[Qemu-devel] [PATCH v2 1/5] char: Use return values instead of error_is_set(errp)

[Markus Armbruster <armbru@redhat.com>]

Using error_is_set(errp) to check whether a function call failed is
fragile: it breaks when errp is null.  Check perfectly suitable return
values instead when possible.  As far as I can tell, errp can't be
null there, but this is more robust and more obviously correct

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 qemu-char.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 54ed244..3eaefc9 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3251,7 +3251,7 @@ CharDriverState *qemu_chr_new_from_opts(QemuOpts *opts,
             }
         }
         ret = qmp_chardev_add(bid ? bid : id, backend, errp);
-        if (error_is_set(errp)) {
+        if (!ret) {
             goto qapi_out;
         }
 
@@ -3263,7 +3263,7 @@ CharDriverState *qemu_chr_new_from_opts(QemuOpts *opts,
             backend->kind = CHARDEV_BACKEND_KIND_MUX;
             backend->mux->chardev = g_strdup(bid);
             ret = qmp_chardev_add(id, backend, errp);
-            if (error_is_set(errp)) {
+            if (!ret) {
                 chr = qemu_chr_find(bid);
                 qemu_chr_delete(chr);
                 chr = NULL;
@@ -3620,18 +3620,18 @@ static int qmp_chardev_open_file_source(char *src, int flags,
 
 static CharDriverState *qmp_chardev_open_file(ChardevFile *file, Error **errp)
 {
-    int flags, in = -1, out = -1;
+    int flags, in = -1, out;
 
     flags = O_WRONLY | O_TRUNC | O_CREAT | O_BINARY;
     out = qmp_chardev_open_file_source(file->out, flags, errp);
-    if (error_is_set(errp)) {
+    if (out < 0) {
         return NULL;
     }
 
     if (file->has_in) {
         flags = O_RDONLY;
         in = qmp_chardev_open_file_source(file->in, flags, errp);
-        if (error_is_set(errp)) {
+        if (in < 0) {
             qemu_close(out);
             return NULL;
         }
@@ -3647,7 +3647,7 @@ static CharDriverState *qmp_chardev_open_serial(ChardevHostdev *serial,
     int fd;
 
     fd = qmp_chardev_open_file_source(serial->device, O_RDWR, errp);
-    if (error_is_set(errp)) {
+    if (fd < 0) {
         return NULL;
     }
     qemu_set_nonblock(fd);
@@ -3665,7 +3665,7 @@ static CharDriverState *qmp_chardev_open_parallel(ChardevHostdev *parallel,
     int fd;
 
     fd = qmp_chardev_open_file_source(parallel->device, O_RDWR, errp);
-    if (error_is_set(errp)) {
+    if (fd < 0) {
         return NULL;
     }
     return qemu_chr_open_pp_fd(fd);
@@ -3692,7 +3692,7 @@ static CharDriverState *qmp_chardev_open_socket(ChardevSocket *sock,
     } else {
         fd = socket_connect(addr, errp, NULL, NULL);
     }
-    if (error_is_set(errp)) {
+    if (fd < 0) {
         return NULL;
     }
     return qemu_chr_open_socket_fd(fd, do_nodelay, is_listen,
@@ -3705,7 +3705,7 @@ static CharDriverState *qmp_chardev_open_udp(ChardevUdp *udp,
     int fd;
 
     fd = socket_dgram(udp->remote, udp->local, errp);
-    if (error_is_set(errp)) {
+    if (fd < 0) {
         return NULL;
     }
     return qemu_chr_open_udp_fd(fd);
-- 
1.9.0