int chattr_fd(int fd, unsigned value, unsigned mask) {
unsigned old_attr, new_attr;
+ struct stat st;
assert(fd >= 0);
+ if (fstat(fd, &st) < 0)
+ return -errno;
+
+ /* Explicitly check whether this is a regular file or
+ * directory. If it is anything else (such as a device node or
+ * fifo), then the ioctl will not hit the file systems but
+ * possibly drivers, where the ioctl might have different
+ * effects. Notably, DRM is using the same ioctl() number. */
+
+ if (!S_ISDIR(st.st_mode) && !S_ISREG(st.st_mode))
+ return -ENOTTY;
+
if (mask == 0)
return 0;
}
int read_attr_fd(int fd, unsigned *ret) {
+ struct stat st;
+
assert(fd >= 0);
+ if (fstat(fd, &st) < 0)
+ return -errno;
+
+ if (!S_ISDIR(st.st_mode) && !S_ISREG(st.st_mode))
+ return -ENOTTY;
+
if (ioctl(fd, FS_IOC_GETFLAGS, ret) < 0)
return -errno;