guy@sun.uucp (Guy Harris) (07/31/86)
Index: bin/tar.c 4.3BSD
Description:
The "directory stack" code in "tar" for setting modification
times on directories has a loop that compares two strings, looking
for the first place at which they differ. However, it assumes
that they will differ somewhere; it does not check for a terminating
'\0'. As such, if they do *not* differ, it runs off the end of
the strings and keeps going until it finds two bytes that *do*
differ.
If the same directory appears on the tape twice, it can encounter
two such strings that do not differ. This means that when it
modifies one string at the point at which it "differed" from
the other string, it will stomp some random location in memory.
we found it tended to happen in the middle of the variables
containing the values of various options, so the "-m" flag magically
turned on when extracting from a tape.
Repeat-By:
Tell "tar" to put a directory and a subdirectory of it, both
containing files, on a tape. Then try extracting the contents
of that tape. Some of the files may not get the modification
time set from the value on the tape.
Fix:
Also incldues a small fix to an error message printout ('perror("")'
does NOT print a colon before its message, so you DO need to stick
it in the "fprintf") and a minor cleanup ("readdir" already
eliminates empty directory slots, so there's no reason to check
for a zero inumber).
*** /arch/4.3/usr/src/bin/tar.c Sat Apr 26 04:35:13 1986
--- ./tar.c Wed Jul 30 14:02:03 1986
***************
*** 512,519 ****
return;
}
while ((dp = readdir(dirp)) != NULL && !term) {
- if (dp->d_ino == 0)
- continue;
if (!strcmp(".", dp->d_name) ||
!strcmp("..", dp->d_name))
continue;
--- 512,517 ----
***************
*** 750,756 ****
nread = readtbuf(&bufp, nwant);
if (write(ofile, bufp, (int)min(nread, bytes)) < 0) {
fprintf(stderr,
! "tar: %s: HELP - extract write error",
dblock.dbuf.name);
perror("");
done(2);
--- 748,754 ----
nread = readtbuf(&bufp, nwant);
if (write(ofile, bufp, (int)min(nread, bytes)) < 0) {
fprintf(stderr,
! "tar: %s: HELP - extract write error: ",
dblock.dbuf.name);
perror("");
done(2);
***************
*** 1358,1364 ****
int savndir;
/* Find common prefix */
! while (*p == *q) {
if (*p++ == '/')
++ndir;
q++;
--- 1356,1362 ----
int savndir;
/* Find common prefix */
! while (*p == *q && *p) {
if (*p++ == '/')
++ndir;
q++;
--
Guy Harris
{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
guy@sun.com (or guy@sun.arpa)