arnold@emory.uucp (Arnold D. Robbins {EUCC}) (08/06/88)
(This does not really apply to strict Vanilla 4.3 BSD. But there are lots
of hybrids out there, and this does apply to Sun systems.)
Subject: tar does not understand FIFO special files
Index: /usr/src/bin/tar.c 4.3BSD + NFS
Index: /usr/man/man5/tar.5 4.3BSD + NFS
Description:
On systems which support System V 'fifo' special files (named
pipes), tar does not recognize such files.
Repeat-By:
On a Mt. Xinu or SunOS 4.0 system, create a FIFO special file, via
mknod. Try to archive it with tar. Watch tar decide that it is
not a file.
Fix:
Apply the following two fixes to the source and the tar(5) man
page respectively. Based on John Gilmore's pdtar, I have used a
linkflag of '6' for fifos; he was following the POSIX spec.
(Yes, I suppose I could switch to his version of tar.)
Your line numbers may vary. In particular, I have Guy Harris's
fix for not unlinking directories already installed.
*** /tmp/,RCSt1016378 Fri Aug 5 15:57:34 1988
--- tar.c Fri Aug 5 12:29:41 1988
***************
*** 659,664 ****
--- 659,714 ----
putempty();
break;
+ #ifdef S_IFIFO
+ case S_IFIFO:
+ tomodes(&stbuf);
+ if (strlen(longname) >= NAMSIZ) {
+ fprintf(stderr, "tar: %s: file name too long\n",
+ longname);
+ return;
+ }
+ strcpy(dblock.dbuf.name, longname);
+ if (stbuf.st_nlink > 1) {
+ struct linkbuf *lp;
+ int found = 0;
+
+ for (lp = ihead; lp != NULL; lp = lp->nextp)
+ if (lp->inum == stbuf.st_ino &&
+ lp->devnum == stbuf.st_dev) {
+ found++;
+ break;
+ }
+ if (found) {
+ strcpy(dblock.dbuf.linkname, lp->pathname);
+ dblock.dbuf.linkflag = '1';
+ sprintf(dblock.dbuf.chksum, "%6o", checksum());
+ (void) writetape( (char *) &dblock);
+ if (vflag)
+ fprintf(vfile, "a %s link to %s\n",
+ longname, lp->pathname);
+ lp->count--;
+ return;
+ }
+ lp = (struct linkbuf *) getmem(sizeof(*lp));
+ if (lp != NULL) {
+ lp->nextp = ihead;
+ ihead = lp;
+ lp->inum = stbuf.st_ino;
+ lp->devnum = stbuf.st_dev;
+ lp->count = stbuf.st_nlink - 1;
+ strcpy(lp->pathname, longname);
+ }
+ }
+ dblock.dbuf.linkname[i] = '\0';
+ dblock.dbuf.linkflag = '6'; /* from POSIX */
+ sprintf(dblock.dbuf.size, "%11lo", 0);
+ sprintf(dblock.dbuf.chksum, "%6o", checksum());
+ if (vflag)
+ fprintf (vfile, "a %s FIFO special file\n", longname);
+ (void) writetape((char *)&dblock);
+ break;
+ #endif
+
default:
fprintf(stderr, "tar: %s is not a file. Not dumped\n",
longname);
***************
*** 698,703 ****
--- 748,774 ----
dodirtimes(&dblock);
continue;
}
+ if (dblock.dbuf.linkflag == '6') { /* FIFO */
+ /*
+ * only unlink non directories or empty
+ * directories
+ */
+ if (rmdir(dblock.dbuf.name) < 0) {
+ if (errno == ENOTDIR)
+ unlink(dblock.dbuf.name);
+ }
+ if (mkfifo(dblock.dbuf.name, stbuf.st_mode&0xfff) < 0) {
+ fprintf (stderr, "tar: can't make FIFO %s: ",
+ dblock.dbuf.name);
+ perror ("");
+ continue;
+ }
+ chown(dblock.dbuf.name, stbuf.st_uid, stbuf.st_gid);
+ if (vflag)
+ fprintf (vfile, "x %s FIFO special file\n",
+ dblock.dbuf.name);
+ continue;
+ }
if (dblock.dbuf.linkflag == '2') { /* symlink */
/*
* only unlink non directories or empty
***************
*** 1433,1436 ****
--- 1504,1531 ----
freemem = 0;
}
return (p);
+ }
+
+ /*
+ * mkfifo
+ *
+ * POSIX call to make a fifo.
+ * This should be either a library routine,
+ * or a system call.
+ *
+ * At some point in the future, will this be where
+ * UNIX domain sockets are made?
+ */
+
+ int
+ mkfifo (path, mode)
+ char *path;
+ int mode;
+ {
+ #ifdef S_IFIFO
+ return mknod (path, mode | S_IFIFO, 0);
+ #else
+ errno = EOPNOTSUPP; /* XXX - for now */
+ return -1;
+ #endif
}
*** /tmp/,RCSt1016434 Fri Aug 5 16:02:47 1988
--- tar.5 Fri Aug 5 16:02:23 1988
***************
*** 112,118 ****
.IR Linkflag
is NULL if the file is ``normal'' or a special file, ASCII `1'
if it is an hard link, and ASCII `2'
! if it is a symbolic link. The name linked-to, if any, is in
.IR linkname,
with a trailing null.
Unused fields of the header are binary zeros (and are included in the
--- 112,121 ----
.IR Linkflag
is NULL if the file is ``normal'' or a special file, ASCII `1'
if it is an hard link, and ASCII `2'
! if it is a symbolic link.
! .I Linkflag
! will be an ASCII `6' if the file is a FIFO special file.
! The name linked-to, if any, is in
.IR linkname,
with a trailing null.
Unused fields of the header are binary zeros (and are included in the
--
Arnold Robbins
ARPA, CSNET: arnold@emory.ARPA BITNET: arnold@emory
UUCP: { decvax, gatech, }!emory!arnold DOMAIN: arnold@emory.edu (soon)
``csh: just say NO!''