ui/input-linux: Do not ignore ioctl() return value

Fix warnings reported by Clang static code analyzer:

    CC      ui/input-linux.o
      ui/input-linux.c:343:9: warning: Value stored to 'rc' is never read
          rc = ioctl(il->fd, EVIOCGBIT(EV_REL, sizeof(relmap)), &relmap);
          ^    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      ui/input-linux.c:351:9: warning: Value stored to 'rc' is never read
          rc = ioctl(il->fd, EVIOCGBIT(EV_ABS, sizeof(absmap)), &absmap);
          ^    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      ui/input-linux.c:354:13: warning: Value stored to 'rc' is never read
              rc = ioctl(il->fd, EVIOCGABS(ABS_X), &absinfo);
              ^    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      ui/input-linux.c:357:13: warning: Value stored to 'rc' is never read
              rc = ioctl(il->fd, EVIOCGABS(ABS_Y), &absinfo);
              ^    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      ui/input-linux.c:365:9: warning: Value stored to 'rc' is never read
          rc = ioctl(il->fd, EVIOCGBIT(EV_KEY, sizeof(keymap)), keymap);
          ^    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      ui/input-linux.c:366:9: warning: Value stored to 'rc' is never read
          rc = ioctl(il->fd, EVIOCGKEY(sizeof(keystate)), keystate);
          ^    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Reported-by: Clang Static Analyzer
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-id: 20200322161219.17757-1-philmd@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 27 insertions, 2 deletions

diff --git a/ui/input-linux.c b/ui/input-linux.c
index a7b280b..ef37b14 100644
--- a/ui/input-linux.c
+++ b/ui/input-linux.c
@@ -334,13 +334,15 @@ static void input_linux_complete(UserCreatable *uc, Error **errp)
 
     rc = ioctl(il->fd, EVIOCGBIT(0, sizeof(evtmap)), &evtmap);
     if (rc < 0) {
-        error_setg(errp, "%s: failed to read event bits", il->evdev);
-        goto err_close;
+        goto err_read_event_bits;
     }
 
     if (evtmap & (1 << EV_REL)) {
         relmap = 0;
         rc = ioctl(il->fd, EVIOCGBIT(EV_REL, sizeof(relmap)), &relmap);
+        if (rc < 0) {
+            goto err_read_event_bits;
+        }
         if (relmap & (1 << REL_X)) {
             il->has_rel_x = true;
         }
@@ -349,12 +351,25 @@ static void input_linux_complete(UserCreatable *uc, Error **errp)
     if (evtmap & (1 << EV_ABS)) {
         absmap = 0;
         rc = ioctl(il->fd, EVIOCGBIT(EV_ABS, sizeof(absmap)), &absmap);
+        if (rc < 0) {
+            goto err_read_event_bits;
+        }
         if (absmap & (1 << ABS_X)) {
             il->has_abs_x = true;
             rc = ioctl(il->fd, EVIOCGABS(ABS_X), &absinfo);
+            if (rc < 0) {
+                error_setg(errp, "%s: failed to get get absolute X value",
+                           il->evdev);
+                goto err_close;
+            }
             il->abs_x_min = absinfo.minimum;
             il->abs_x_max = absinfo.maximum;
             rc = ioctl(il->fd, EVIOCGABS(ABS_Y), &absinfo);
+            if (rc < 0) {
+                error_setg(errp, "%s: failed to get get absolute Y value",
+                           il->evdev);
+                goto err_close;
+            }
             il->abs_y_min = absinfo.minimum;
             il->abs_y_max = absinfo.maximum;
         }
@@ -363,7 +378,14 @@ static void input_linux_complete(UserCreatable *uc, Error **errp)
     if (evtmap & (1 << EV_KEY)) {
         memset(keymap, 0, sizeof(keymap));
         rc = ioctl(il->fd, EVIOCGBIT(EV_KEY, sizeof(keymap)), keymap);
+        if (rc < 0) {
+            goto err_read_event_bits;
+        }
         rc = ioctl(il->fd, EVIOCGKEY(sizeof(keystate)), keystate);
+        if (rc < 0) {
+            error_setg(errp, "%s: failed to get global key state", il->evdev);
+            goto err_close;
+        }
         for (i = 0; i < KEY_CNT; i++) {
             if (keymap[i / 8] & (1 << (i % 8))) {
                 if (linux_is_button(i)) {
@@ -390,6 +412,9 @@ static void input_linux_complete(UserCreatable *uc, Error **errp)
     il->initialized = true;
     return;
 
+err_read_event_bits:
+    error_setg(errp, "%s: failed to read event bits", il->evdev);
+
 err_close:
     close(il->fd);
     return;