util/cutils: Let qemu_strtosz*() optionally reject trailing crap

Change the qemu_strtosz() & friends to return -EINVAL when @endptr is
null and the conversion doesn't consume the string completely.
Matches how qemu_strtol() & friends work.

Only test_qemu_strtosz_simple() passes a null @endptr.  No functional
change there, because its conversion consumes the string.

Simplify callers that use @endptr only to fail when it doesn't point
to '\0' to pass a null @endptr instead.

Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com> (maintainer:X86)
Cc: Kevin Wolf <kwolf@redhat.com> (supporter:Block layer core)
Cc: Max Reitz <mreitz@redhat.com> (supporter:Block layer core)
Cc: qemu-block@nongnu.org (open list:Block layer core)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1487708048-2131-22-git-send-email-armbru@redhat.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/qemu-img.c b/qemu-img.c
index 4062917..39ef581 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -370,14 +370,9 @@ static int add_old_style_options(const char *fmt, QemuOpts *opts,
 
 static int64_t cvtnum(const char *s)
 {
-    char *end;
     int64_t ret;
 
-    ret = qemu_strtosz(s, &end);
-    if (*end != '\0') {
-        /* Detritus at the end of the string */
-        return -EINVAL;
-    }
+    ret = qemu_strtosz(s, NULL);
     return ret;
 }