storage: tweak condition to properly test lseek

According to the POSIX standard, off_t (returned by lseek) is defined as
signed integral type no shorter than int. Because our offset variable is defined
as unsigned long long, the original check was passed successfully if UINT64_MAX had
been used as offset value, due to implicit conversion.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1177219
(cherry picked from commit 3fde7986d6694f122ae919d68ec64eee79bd51db)

diff --git a/src/fdstream.c b/src/fdstream.c
index 5d80fc23fcdb520fa733e7d7b9cb635549e23e0b..b8ea86e435816d10f825501cf08f468f7029f628 100644 (file)
--- a/src/fdstream.c
+++ b/src/fdstream.c
@@ -610,7 +610,7 @@ virFDStreamOpenFileInternal(virStreamPtr st,
     }
 
     if (offset &&
-        lseek(fd, offset, SEEK_SET) != offset) {
+        lseek(fd, offset, SEEK_SET) < 0) {
         virReportSystemError(errno,
                              _("Unable to seek %s to %llu"),
                              path, offset);