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Description of problem:
There is a while loop in the rpm source file lib/misc.c domd5()
function that is supposed to calculate the md5sum for a file. 
However, the while loop doesn't actually do anything; that is, it 
reads the file, but does not update the digest. This results in 
config files always appearing to be modified, which causes RPM to 
perform the wrong actions when determining the fate of a config file.

Version-Release number of selected component (if applicable):


How reproducible:
Always

Steps to Reproduce:
1.Create a spec file that builds an RPM with one %config(noreplace) 
  file. The file's contents should be the version and release of the
  RPM.
2.Build and install this RPM.
3.Change the release in the spec file, and then build and upgrade the
  resulting RPM.
	

Actual Results:  The new RPM ended up depositing its config file with the .rpmnew 
extension.

Expected Results:  Since the config file hadn't actually changed from the first 
installation, it should have been overwritten with the contents of
the config file from the new release.

Additional info:


fdUpdateDigests() should probably be called in the code below.

[admin@apphost-61 rpm-4.0.4]$ grep -A 30 -B 1 domd5
/usr/src/redhat/BUILD/rpm-4.0.4/lib/misc.c

int domd5(const char * fn, /*@out@*/ unsigned char * digest, int asAscii)
        /*@modifies digest, fileSystem @*/
{
    int rc;
    FD_t fd = Fopen(fn, "r.ufdio");
    unsigned char buf[BUFSIZ];
    unsigned char * md5sum = NULL;
    size_t md5len;

    if (fd == NULL || Ferror(fd)) {
        if (fd)
            (void) Fclose(fd);
        return 1;
    }

    fdInitDigest(fd, PGPHASHALGO_MD5, 0);
    while ((rc = Fread(buf, sizeof(buf[0]), sizeof(buf), fd)) > 0)
        {};
    fdFiniDigest(fd, PGPHASHALGO_MD5, (void **)&md5sum, &md5len, asAscii);

    if (Ferror(fd))
        rc = 1;
    (void) Fclose(fd);

    if (!rc)
        memcpy(digest, md5sum, md5len);
    md5sum = _free(md5sum);

    return rc;
}