archie/prospero/lib/pfs/rd_vlink.c

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2024-05-27 16:13:40 +02:00
/*
* Copyright (c) 1989, 1990 by the University of Washington
* Copyright (c) 1993 by the University of Southern California
*
* For copying and distribution information, please see the files
* <uw-copyright.h> and <usc-copyr.h>
*/
#include <uw-copyright.h>
#include <usc-copyr.h>
#include <stdio.h>
#include <string.h>
#include <pfs.h>
#include <perrno.h>
#include <pmachine.h>
static VLINK rd_vslink();
/*
* rd_vlink will read the named link, expanding any symbolic links
* along the way. Call rd_slink if you do not want to expand the
* final sym_link.
*/
VLINK
rd_vlink(const char *path)
{
return(rd_vslink(path,SYMLINK_NESTING));
}
/*
* rd_slink will read the named link, returing the result without
* expansion, even if the result is a symbolic link.
*/
VLINK
rd_slink(const char *path)
{
return(rd_vslink(path,-1));
}
extern char *p_uln_lastcomp_to_linkname(const char *s);
static VLINK
rd_vslink(path,depth)
const char *path; /* Pathname for links to be returned */
int depth; /* How many levels of sym links to expand */
{
char pth[MAX_VPATH]; /* Working copy of pathname */
char *p = pth; /* So we can use it as a pointer */
char *c; /* Component part of name */
char *d; /* Directory part of name */
char *slash; /* Position of slash */
char *colon; /* Position of colon */
int flags;
VDIR_ST dir_st;
VDIR dir = &dir_st;
VLINK v;
vdir_init(dir);
/* special case just a . as a name for the current working directory,
by mapping it onto the empty string. . */
if (strequal(path, ".")) ++path;
strcpy(p,path);
d = p;
slash = p_uln_rindex(p,'/');
colon = p_uln_rindex(p,':');
if(colon && (!slash || (colon > slash))) {
*(colon + 1) = '\0';
c = p_uln_lastcomp_to_linkname(p_uln_rindex(path,':') + 1);
}
else if(slash) {
if(slash == p) d = "/";
*slash = '\0';
c = p_uln_lastcomp_to_linkname(slash + 1);
}
else if (strequal(path, "..")) {
/* Special case just .. as a name for the superior directory. */
d = "..";
c = NULL;
} else {
d = "";
c = p_uln_lastcomp_to_linkname(p);
}
if(c && *c) flags = RVD_FIND;
else flags = RVD_DFILE_ONLY;
perrno = rd_vdir(d,c,dir,flags);
if(perrno || !dir->links) {
if (!perrno) perrno = PFAILURE;
vllfree(dir->links);
vllfree(dir->ulinks);
return(NULL);
}
vllfree(dir->ulinks);
if((strncmp(dir->links->target,"SYMBOLIC",8) == 0) &&
(strncmp(dir->links->hosttype,"VIRTUAL-SYSTEM",14) == 0)) {
if(depth > 0) {
if (sizeof pth <
qsprintf(pth, sizeof pth,
"/VIRTUAL-SYSTEMS/%s/ROOT%s%s",dir->links->host,
((*(dir->links->hsoname) == '/') ? "" : "/"),
dir->links->hsoname))
internal_error("pth too small!");
v = rd_vslink(pth,depth-1);
vllfree(dir->links);
if (!perrno) perrno = PFAILURE;
return(v);
}
else if(depth == 0) {
vllfree(dir->links);
perrno = PFS_SYMLINK_DEPTH;
return(NULL);
} /* depth < 0 means don't expand symlink. */
}
return(dir->links);
}