commit 8fbd3c149da34d20499ada0e03022e84e9746036
author Andrew de los Reyes <adlr@chromium.org> Wed May 08 16:30:50 2013
committer ChromeBot <chrome-bot@google.com> Wed May 08 19:05:40 2013
tree cdc6c87953bf53afddfbebb7bb137243f033a393
parent 2eeae939b5dfdba481958e34967184d1028f8965

libevdev: Better error handling, better handling of bitmask reads.

Since bitmasks are stored as arrays of longs, and sizeof(long) depends
on the platform you're on (32 or 64 bit), reading in bitmasks was
always done in sizeof(long) increments. If a device is 32 bits, it
would generate 4 bytes for the 'bit' bitmask, but then when reading,
we would expect 8, and overrun the log. With this CL, we look for
end-of-line and stop.

BUG=chromium:239070
TEST=Able to make and replay new Spring regression test

Change-Id: I286f2ed36df7d7c9c5b0588941c8a386466d0d40
Reviewed-on: https://gerrit.chromium.org/gerrit/50468
Reviewed-by: Dennis Kempin <denniskempin@chromium.org>
Commit-Queue: Andrew de los Reyes <adlr@chromium.org>
Tested-by: Andrew de los Reyes <adlr@chromium.org>

src/libevdev.c

diff --git a/src/libevdev.c b/src/libevdev.c
index 0bf71bd..889a759 100644
--- a/src/libevdev.c
+++ b/src/libevdev.c
@@ -334,37 +334,51 @@
   int ret;
 
   ret = fscanf(fp, "# device: %1024[^\n]\n", info->name);
-  if (ret <= 0)
+  if (ret <= 0) {
+    fprintf(stderr, "Parse device name failed\n");
     return ret;
+  }
 
   ret = EvdevReadBitmask(fp, "bit", info->bitmask, sizeof(info->bitmask));
-  if (ret <= 0)
+  if (ret <= 0) {
+    fprintf(stderr, "Parse device bit failed\n");
     return ret;
+  }
 
   ret = EvdevReadBitmask(fp, "key", info->key_bitmask,
                          sizeof(info->key_bitmask));
-  if (ret <= 0)
+  if (ret <= 0) {
+    fprintf(stderr, "Parse device key failed\n");
     return ret;
+  }
 
   ret = EvdevReadBitmask(fp, "rel", info->rel_bitmask,
                          sizeof(info->rel_bitmask));
-  if (ret <= 0)
+  if (ret <= 0) {
+    fprintf(stderr, "Parse device rel failed\n");
     return ret;
+  }
 
   ret = EvdevReadBitmask(fp, "abs", info->abs_bitmask,
                          sizeof(info->abs_bitmask));
-  if (ret <= 0)
+  if (ret <= 0) {
+    fprintf(stderr, "Parse device abs failed\n");
     return ret;
+  }
 
   ret = EvdevReadBitmask(fp, "led", info->led_bitmask,
                          sizeof(info->led_bitmask));
-  if (ret <= 0)
+  if (ret <= 0) {
+    fprintf(stderr, "Parse device led failed\n");
     return ret;
+  }
 
   ret = EvdevReadBitmask(fp, "prp", info->prop_bitmask,
                          sizeof(info->prop_bitmask));
-  if (ret <= 0)
+  if (ret <= 0) {
+    fprintf(stderr, "Parse device prp failed\n");
     return ret;
+  }
 
   for (int i = ABS_X; i <= ABS_MAX; i++) {
       if (TestBit(i, info->abs_bitmask)) {
@@ -373,8 +387,10 @@
           ret = fscanf(fp, "# absinfo: %d %d %d %d %d %d\n",
                        &abs_index, &abs.minimum, &abs.maximum,
                        &abs.fuzz, &abs.flat, &abs.resolution);
-          if (ret <= 0 || abs_index != i)
+          if (ret <= 0 || abs_index != i) {
+            fprintf(stderr, "Parse device absinfo failed on %d\n", i);
             return -1;
+          }
           info->absinfo[i] = abs;
       }
   }
@@ -387,8 +403,13 @@
   int value;
   int ret = fscanf(fp, "E: %lu.%06u %04x %04x %d\n",
        &sec, &usec, &type, &code, &value);
-  if (ret <= 0)
+  if (ret == EOF)
+    return -1;
+  if (ret <= 0) {
+    int err = errno;
+    fprintf(stderr, "EvdevReadEventFromFile failed: %d, errno: %d\n", ret, err);
     return ret;
+  }
 
   ev->time.tv_sec = sec;
   ev->time.tv_usec = usec;
@@ -402,12 +423,23 @@
                               unsigned long* bitmask, size_t num_bytes) {
   unsigned char* bytes = (unsigned char*)bitmask;
   int ret;
-  char name[64];
+  char name[64] = { 0 };
 
   ret = fscanf(fp, "# %63[^:]:", name);
-  if (ret <= 0 || strcmp(name, expected_name))
-    return ret;
-  for (int i = 0; i < num_bytes; ++i) {
+  if (ret <= 0 || strcmp(name, expected_name)) {
+    fprintf(stderr, "EvdevReadBitmask: %d <= 0 or [%s]!=[%s]\n",
+            ret, name, expected_name);
+    return -1;
+  }
+  memset(bitmask, 0, num_bytes);
+  for (size_t i = 0; i < num_bytes; ++i) {
+    // Make sure we don't go off the end of the line
+    int next_char = fgetc(fp);
+    if (next_char != EOF)
+      ungetc(next_char, fp);
+    if (next_char == '\n' || next_char == EOF)
+      break;
+
     unsigned int tmp;
     ret = fscanf(fp, " %02X", &tmp);
     if (ret <= 0)