[PATCH] xfs_io: don't assign cvtnum() return to unsigned var

[Eric Sandeen <sandeen@xxxxxxxxxxx>]

cvtnum() returns -1LL for unparseable values, but if we
assign to a signed var, we can't test it:

xfs_io> mincore 0 xxx
range (0:0) is beyond mapping (0:1048576)

Use a temporary signed var so we can detect the error:

xfs_io> mincore 0 xxx
non-numeric length argument -- xxx

and also test whether it may overflow a size_t.

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxxx>
---

diff --git a/io/mincore.c b/io/mincore.c
index f863f84..d534540 100644
--- a/io/mincore.c
+++ b/io/mincore.c
@@ -30,7 +30,7 @@ mincore_f(
        int             argc,
        char            **argv)
 {
-       off64_t         offset;
+       off64_t         offset, llength;
        size_t          length;
        size_t          blocksize, sectsize;
        void            *start;
@@ -49,12 +49,17 @@ mincore_f(
                                argv[1]);
                        return 0;
                }
-               length = cvtnum(blocksize, sectsize, argv[2]);
-               if (length < 0) {
+               llength = cvtnum(blocksize, sectsize, argv[2]);
+               if (llength < 0) {
                        printf(_("non-numeric length argument -- %s\n"),
                                argv[2]);
                        return 0;
-               }
+               } else if (llength > (size_t)llength) {
+                       printf(_("length argument too large -- %lld\n"),
+                               llength);
+                       return 0;
+               } else
+                       length = (size_t)llength;
        } else {
                return command_usage(&mincore_cmd);
        }