298 lines
8.3 KiB
C
298 lines
8.3 KiB
C
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/* $Source: /u/mark/src/pax/RCS/link.c,v $
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*
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* $Revision: 1.2 $
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*
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* link.c - functions for handling multiple file links
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*
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* DESCRIPTION
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*
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* These function manage the link chains which are used to keep track
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* of outstanding links during archive reading and writing.
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*
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* AUTHOR
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*
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* Mark H. Colburn, NAPS International (mark@jhereg.mn.org)
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*
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* Sponsored by The USENIX Association for public distribution.
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*
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* Copyright (c) 1989 Mark H. Colburn.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice is duplicated in all such
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* forms and that any documentation, advertising materials, and other
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* materials related to such distribution and use acknowledge that the
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* software was developed * by Mark H. Colburn and sponsored by The
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* USENIX Association.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* $Log: link.c,v $
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* Revision 1.2 89/02/12 10:04:38 mark
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* 1.2 release fixes
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*
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* Revision 1.1 88/12/23 18:02:12 mark
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* Initial revision
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*
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*/
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#ifndef lint
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static char *ident = "$Id: link.c,v 1.2 89/02/12 10:04:38 mark Exp $";
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static char *copyright = "Copyright (c) 1989 Mark H. Colburn.\nAll rights reserved.\n";
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#endif /* ! lint */
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/* Headers */
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#include "pax.h"
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/* Defines */
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/*
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* Address link information base.
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*/
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#define LINKHASH(ino) (linkbase + (ino) % NEL(linkbase))
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/*
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* Number of array elements.
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*/
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#define NEL(a) (sizeof(a) / sizeof(*(a)))
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/* Internal Identifiers */
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static Link *linkbase[256]; /* Unresolved link information */
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/* linkfrom - find a file to link from
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*
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* DESCRIPTION
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*
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* Linkfrom searches the link chain to see if there is a file in the
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* link chain which has the same inode number as the file specified
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* by the stat block pointed at by asb. If a file is found, the
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* name is returned to the caller, otherwise a NULL is returned.
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*
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* PARAMETERS
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*
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* char *name - name of the file which we are attempting
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* to find a link for
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* Stat *asb - stat structure of file to find a link to
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*
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* RETURNS
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*
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* Returns a pointer to a link structure, or NULL if unsuccessful.
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*
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*/
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Link *linkfrom(char *name, Stat *asb)
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{
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Link *linkp;
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Link *linknext;
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Path *path;
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Path *pathnext;
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Link **abase;
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#ifdef DF_TRACE_DEBUG
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printf("DF_TRACE_DEBUG: Link *linkfrom() in link.c\n");
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#endif
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for (linkp = *(abase = LINKHASH(asb->sb_ino)); linkp; linkp = linknext) {
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if (linkp->l_nlink == 0) {
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if (linkp->l_name) {
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free((char *) linkp->l_name);
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}
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if (linknext = linkp->l_forw) {
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linknext->l_back = linkp->l_back;
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}
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if (linkp->l_back) {
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linkp->l_back->l_forw = linkp->l_forw;
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}
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free((char *) linkp);
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*abase = (Link *)NULL;
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} else if (linkp->l_ino == asb->sb_ino && linkp->l_dev == asb->sb_dev) {
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/*
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* check to see if a file with the name "name" exists in the
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* chain of files which we have for this particular link
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*/
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for (path = linkp->l_path; path; path = pathnext) {
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if (strcmp(path->p_name, name) == 0) {
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--linkp->l_nlink;
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if (path->p_name) {
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free(path->p_name);
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}
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if (pathnext = path->p_forw) {
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pathnext->p_back = path->p_back;
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}
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if (path->p_back) {
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path->p_back->p_forw = pathnext;
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}
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if (linkp->l_path == path) {
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linkp->l_path = pathnext;
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}
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free(path);
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return (linkp);
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}
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pathnext = path->p_forw;
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}
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return ((Link *)NULL);
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} else {
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linknext = linkp->l_forw;
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}
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}
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return ((Link *)NULL);
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}
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/* islink - determine whether a given file really a link
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*
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* DESCRIPTION
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*
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* Islink searches the link chain to see if there is a file in the
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* link chain which has the same inode number as the file specified
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* by the stat block pointed at by asb. If a file is found, a
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* non-zero value is returned to the caller, otherwise a 0 is
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* returned.
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*
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* PARAMETERS
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*
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* char *name - name of file to check to see if it is link.
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* Stat *asb - stat structure of file to find a link to
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*
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* RETURNS
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*
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* Returns a pointer to a link structure, or NULL if unsuccessful.
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*
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*/
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Link *islink(char *name, Stat *asb)
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{
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Link *linkp;
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Link *linknext;
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#ifdef DF_TRACE_DEBUG
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printf("DF_TRACE_DEBUG: Link *islink() in link.c\n");
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#endif
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for (linkp = *(LINKHASH(asb->sb_ino)); linkp; linkp = linknext) {
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if (linkp->l_ino == asb->sb_ino && linkp->l_dev == asb->sb_dev) {
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if (strcmp(name, linkp->l_name) == 0) {
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return ((Link *)NULL);
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}
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return (linkp);
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} else {
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linknext = linkp->l_forw;
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}
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}
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return ((Link *)NULL);
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}
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/* linkto - remember a file with outstanding links
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*
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* DESCRIPTION
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*
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* Linkto adds the specified file to the link chain. Any subsequent
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* calls to linkfrom which have the same inode will match the file
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* just entered. If not enough space is available to make the link
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* then the item is not added to the link chain, and a NULL is
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* returned to the calling function.
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*
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* PARAMETERS
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*
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* char *name - name of file to remember
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* Stat *asb - pointer to stat structure of file to remember
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*
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* RETURNS
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*
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* Returns a pointer to the associated link structure, or NULL when
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* linking is not possible.
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*
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*/
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Link *linkto(char *name, Stat *asb)
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{
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Link *linkp;
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Link *linknext;
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Path *path;
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Link **abase;
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#ifdef DF_TRACE_DEBUG
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printf("DF_TRACE_DEBUG: Link *linkto() in link.c\n");
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#endif
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for (linkp = *(LINKHASH(asb->sb_ino)); linkp; linkp = linknext) {
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if (linkp->l_ino == asb->sb_ino && linkp->l_dev == asb->sb_dev) {
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if ((path = (Path *) mem_get(sizeof(Path))) == (Path *)NULL ||
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(path->p_name = mem_str(name)) == (char *)NULL) {
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#ifdef DF_TRACE_DEBUG
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printf("DF_TRACE_DEBUG: () in link.c\n");
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#endif
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return ((Link *)NULL);
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}
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if (path->p_forw = linkp->l_path) {
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if (linkp->l_path->p_forw) {
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linkp->l_path->p_forw->p_back = path;
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}
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} else {
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linkp->l_path = path;
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}
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path->p_back = (Path *)NULL;
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return (linkp);
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} else {
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linknext = linkp->l_forw;
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}
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}
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/*
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* This is a brand new link, for which there is no other information
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*/
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if ((asb->sb_mode & S_IFMT) == S_IFDIR
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|| (linkp = (Link *) mem_get(sizeof(Link))) == (Link *)NULL
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|| (linkp->l_name = mem_str(name)) == (char *)NULL) {
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return ((Link *)NULL);
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}
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linkp->l_dev = asb->sb_dev;
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linkp->l_ino = asb->sb_ino;
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linkp->l_nlink = (ushort)(asb->sb_nlink - 1);
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linkp->l_size = asb->sb_size;
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linkp->l_path = (Path *)NULL;
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if (linkp->l_forw = *(abase = LINKHASH(asb->sb_ino))) {
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linkp->l_forw->l_back = linkp;
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} else {
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*abase = linkp;
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}
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linkp->l_back = (Link *)NULL;
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return (linkp);
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}
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/* linkleft - complain about files with unseen links
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*
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* DESCRIPTION
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*
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* Linksleft scans through the link chain to see if there were any
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* files which have outstanding links that were not processed by the
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* archive. For each file in the link chain for which there was not
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* a file, and error message is printed.
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*/
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void linkleft(void)
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{
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Link *lp;
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Link **base;
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#ifdef DF_TRACE_DEBUG
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printf("DF_TRACE_DEBUG: void linkleft() in link.c\n");
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#endif
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for (base = linkbase; base < linkbase + NEL(linkbase); ++base) {
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for (lp = *base; lp; lp = lp->l_forw) {
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if (lp->l_nlink) {
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warn(lp->l_path->p_name, "Unseen link(s)");
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}
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}
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}
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}
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