ref: 1b09060f468f530af2f4ef75441a40084e912e54
dir: /sys/src/ape/cmd/pdksh/path.c/
#include "sh.h"
#include "ksh_stat.h"
/*
* Contains a routine to search a : separated list of
* paths (a la CDPATH) and make appropiate file names.
* Also contains a routine to simplify .'s and ..'s out of
* a path name.
*
* Larry Bouzane (larry@cs.mun.ca)
*/
/*
* $Log: path.c,v $
* Revision 1.2 1994/05/19 18:32:40 michael
* Merge complete, stdio replaced, various fixes. (pre autoconf)
*
* Revision 1.1 1994/04/06 13:14:03 michael
* Initial revision
*
* Revision 4.2 1990/12/06 18:05:24 larry
* Updated test code to reflect parameter change.
* Fixed problem with /a/./.dir being simplified to /a and not /a/.dir due
* to *(cur+2) == *f test instead of the correct cur+2 == f
*
* Revision 4.1 90/10/29 14:42:19 larry
* base MUN version
*
* Revision 3.1.0.4 89/02/16 20:28:36 larry
* Forgot to set *pathlist to NULL when last changed make_path().
*
* Revision 3.1.0.3 89/02/13 20:29:55 larry
* Fixed up cd so that it knew when a node from CDPATH was used and would
* print a message only when really necessary.
*
* Revision 3.1.0.2 89/02/13 17:51:22 larry
* Merged with Eric Gisin's version.
*
* Revision 3.1.0.1 89/02/13 17:50:58 larry
* *** empty log message ***
*
* Revision 3.1 89/02/13 17:49:28 larry
* *** empty log message ***
*
*/
#ifdef S_ISLNK
static char *do_phys_path ARGS((XString *xsp, char *xp, const char *path));
#endif /* S_ISLNK */
/*
* Makes a filename into result using the following algorithm.
* - make result NULL
* - if file starts with '/', append file to result & set cdpathp to NULL
* - if file starts with ./ or ../ append cwd and file to result
* and set cdpathp to NULL
* - if the first element of cdpathp doesnt start with a '/' xx or '.' xx
* then cwd is appended to result.
* - the first element of cdpathp is appended to result
* - file is appended to result
* - cdpathp is set to the start of the next element in cdpathp (or NULL
* if there are no more elements.
* The return value indicates whether a non-null element from cdpathp
* was appened to result.
*/
int
make_path(const char *cwd, const char *file, char **cdpathp, XString *xsp, int *phys_pathp)
{
int rval = 0;
int use_cdpath = 1;
char *plist;
int len;
int plen = 0;
char *xp = Xstring(*xsp, xp);
if (!file)
file = null;
if (!ISRELPATH(file)) {
*phys_pathp = 0;
use_cdpath = 0;
} else {
if (file[0] == '.') {
char c = file[1];
if (c == '.')
c = file[2];
if (ISDIRSEP(c) || c == '\0')
use_cdpath = 0;
}
plist = *cdpathp;
if (!plist)
use_cdpath = 0;
else if (use_cdpath) {
char *pend;
for (pend = plist; *pend && *pend != PATHSEP; pend++)
;
plen = pend - plist;
*cdpathp = *pend ? ++pend : (char *) 0;
}
if ((use_cdpath == 0 || !plen || ISRELPATH(plist))
&& (cwd && *cwd))
{
len = strlen(cwd);
XcheckN(*xsp, xp, len);
memcpy(xp, cwd, len);
xp += len;
if (!ISDIRSEP(cwd[len - 1]))
Xput(*xsp, xp, DIRSEP);
}
*phys_pathp = Xlength(*xsp, xp);
if (use_cdpath && plen) {
XcheckN(*xsp, xp, plen);
memcpy(xp, plist, plen);
xp += plen;
if (!ISDIRSEP(plist[plen - 1]))
Xput(*xsp, xp, DIRSEP);
rval = 1;
}
}
len = strlen(file) + 1;
XcheckN(*xsp, xp, len);
memcpy(xp, file, len);
if (!use_cdpath)
*cdpathp = (char *) 0;
return rval;
}
/*
* Simplify pathnames containing "." and ".." entries.
* ie, simplify_path("/a/b/c/./../d/..") returns "/a/b"
*/
void
simplify_path(char *path)
{
char *cur;
char *t;
int isrooted;
char *very_start = path;
char *start;
if (!*path)
return;
if ((isrooted = ISROOTEDPATH(path)))
very_start++;
#if defined (OS2) || defined (__CYGWIN__)
if (path[0] && path[1] == ':') /* skip a: */
very_start += 2;
#endif /* OS2 || __CYGWIN__ */
/* Before After
* /foo/ /foo
* /foo/../../bar /bar
* /foo/./blah/.. /foo
* . .
* .. ..
* ./foo foo
* foo/../../../bar ../../bar
* OS2 and CYGWIN:
* a:/foo/../.. a:/
* a:. a:
* a:.. a:..
* a:foo/../../blah a:../blah
*/
#ifdef __CYGWIN__
/* preserve leading double-slash on pathnames (for UNC paths) */
if (path[0] && ISDIRSEP(path[0]) && path[1] && ISDIRSEP(path[1]))
very_start++;
#endif /* __CYGWIN__ */
for (cur = t = start = very_start; ; ) {
/* treat multiple '/'s as one '/' */
while (ISDIRSEP(*t))
t++;
if (*t == '\0') {
if (cur == path)
/* convert empty path to dot */
*cur++ = '.';
*cur = '\0';
break;
}
if (t[0] == '.') {
if (!t[1] || ISDIRSEP(t[1])) {
t += 1;
continue;
} else if (t[1] == '.' && (!t[2] || ISDIRSEP(t[2]))) {
if (!isrooted && cur == start) {
if (cur != very_start)
*cur++ = DIRSEP;
*cur++ = '.';
*cur++ = '.';
start = cur;
} else if (cur != start)
while (--cur > start && !ISDIRSEP(*cur))
;
t += 2;
continue;
}
}
if (cur != very_start)
*cur++ = DIRSEP;
/* find/copy next component of pathname */
while (*t && !ISDIRSEP(*t))
*cur++ = *t++;
}
}
void
set_current_wd(char *path)
{
int len;
char *p = path;
if (!p && !(p = ksh_get_wd((char *) 0, 0)))
p = null;
len = strlen(p) + 1;
if (len > current_wd_size)
current_wd = aresize(current_wd, current_wd_size = len, APERM);
memcpy(current_wd, p, len);
if (p != path && p != null)
afree(p, ATEMP);
}
#ifdef S_ISLNK
char *
get_phys_path(const char *path)
{
XString xs;
char *xp;
Xinit(xs, xp, strlen(path) + 1, ATEMP);
xp = do_phys_path(&xs, xp, path);
if (!xp)
return (char *) 0;
if (Xlength(xs, xp) == 0)
Xput(xs, xp, DIRSEP);
Xput(xs, xp, '\0');
return Xclose(xs, xp);
}
static char *
do_phys_path(XString *xsp, char *xp, const char *path)
{
const char *p, *q;
int len, llen;
int savepos;
char lbuf[PATH];
Xcheck(*xsp, xp);
for (p = path; p; p = q) {
while (ISDIRSEP(*p))
p++;
if (!*p)
break;
len = (q = ksh_strchr_dirsep(p)) ? q - p : strlen(p);
if (len == 1 && p[0] == '.')
continue;
if (len == 2 && p[0] == '.' && p[1] == '.') {
while (xp > Xstring(*xsp, xp)) {
xp--;
if (ISDIRSEP(*xp))
break;
}
continue;
}
savepos = Xsavepos(*xsp, xp);
Xput(*xsp, xp, DIRSEP);
XcheckN(*xsp, xp, len + 1);
memcpy(xp, p, len);
xp += len;
*xp = '\0';
llen = readlink(Xstring(*xsp, xp), lbuf, sizeof(lbuf) - 1);
if (llen < 0) {
/* EINVAL means it wasn't a symlink... */
if (errno != EINVAL)
return (char *) 0;
continue;
}
lbuf[llen] = '\0';
/* If absolute path, start from scratch.. */
xp = ISABSPATH(lbuf) ? Xstring(*xsp, xp)
: Xrestpos(*xsp, xp, savepos);
if (!(xp = do_phys_path(xsp, xp, lbuf)))
return (char *) 0;
}
return xp;
}
#endif /* S_ISLNK */
#ifdef TEST
main(argc, argv)
{
int rv;
char *cp, cdpath[256], pwd[256], file[256], result[256];
printf("enter CDPATH: "); gets(cdpath);
printf("enter PWD: "); gets(pwd);
while (1) {
if (printf("Enter file: "), gets(file) == 0)
return 0;
cp = cdpath;
do {
rv = make_path(pwd, file, &cp, result, sizeof(result));
printf("make_path returns (%d), \"%s\" ", rv, result);
simplify_path(result);
printf("(simpifies to \"%s\")\n", result);
} while (cp);
}
}
#endif /* TEST */