bin/ksh/path.c

   1 /*      $NetBSD: path.c,v 1.8 2009/04/25 05:11:37 lukem Exp $   */
   2 #include <sys/cdefs.h>
   3
   4 #ifndef lint
   5 __RCSID("$NetBSD: path.c,v 1.8 2009/04/25 05:11:37 lukem Exp $");
   6 #endif
   7
   8
   9 #include "sh.h"
  10 #include "ksh_stat.h"
  11
  12 /*
  13  *      Contains a routine to search a : separated list of
  14  *      paths (a la CDPATH) and make appropriate file names.
  15  *      Also contains a routine to simplify .'s and ..'s out of
  16  *      a path name.
  17  *
  18  *      Larry Bouzane (larry@cs.mun.ca)
  19  */
  20
  21 #ifdef S_ISLNK
  22 static char     *do_phys_path ARGS((XString *, char *, const char *));
  23 #endif /* S_ISLNK */
  24
  25 /*
  26  *      Makes a filename into result using the following algorithm.
  27  *      - make result NULL
  28  *      - if file starts with '/', append file to result & set cdpathp to NULL
  29  *      - if file starts with ./ or ../ append cwd and file to result
  30  *        and set cdpathp to NULL
  31  *      - if the first element of cdpathp doesnt start with a '/' xx or '.' xx
  32  *        then cwd is appended to result.
  33  *      - the first element of cdpathp is appended to result
  34  *      - file is appended to result
  35  *      - cdpathp is set to the start of the next element in cdpathp (or NULL
  36  *        if there are no more elements.
  37  *      The return value indicates whether a non-null element from cdpathp
  38  *      was appended to result.
  39  */
  40 int
  41 make_path(cwd, file, cdpathp, xsp, phys_pathp)
  42         const char *cwd;
  43         const char *file;
  44         char    **cdpathp;      /* & of : separated list */
  45         XString *xsp;
  46         int     *phys_pathp;
  47 {
  48         int     rval = 0;
  49         int     use_cdpath = 1;
  50         char    *plist;
  51         int     len;
  52         int     plen = 0;
  53         char    *xp = Xstring(*xsp, xp);
  54
  55         if (!file)
  56                 file = null;
  57
  58         if (!ISRELPATH(file)) {
  59                 *phys_pathp = 0;
  60                 use_cdpath = 0;
  61         } else {
  62                 if (file[0] == '.') {
  63                         char c = file[1];
  64
  65                         if (c == '.')
  66                                 c = file[2];
  67                         if (ISDIRSEP(c) || c == '\0')
  68                                 use_cdpath = 0;
  69                 }
  70
  71                 plist = *cdpathp;
  72                 if (!plist)
  73                         use_cdpath = 0;
  74                 else if (use_cdpath) {
  75                         char *pend;
  76
  77                         for (pend = plist; *pend && *pend != PATHSEP; pend++)
  78                                 ;
  79                         plen = pend - plist;
  80                         *cdpathp = *pend ? ++pend : (char *) 0;
  81                 }
  82
  83                 if ((use_cdpath == 0 || !plen || ISRELPATH(plist))
  84                     && (cwd && *cwd))
  85                 {
  86                         len = strlen(cwd);
  87                         XcheckN(*xsp, xp, len);
  88                         memcpy(xp, cwd, len);
  89                         xp += len;
  90                         if (!ISDIRSEP(cwd[len - 1]))
  91                                 Xput(*xsp, xp, DIRSEP);
  92                 }
  93                 *phys_pathp = Xlength(*xsp, xp);
  94                 if (use_cdpath && plen) {
  95                         XcheckN(*xsp, xp, plen);
  96                         memcpy(xp, plist, plen);
  97                         xp += plen;
  98                         if (!ISDIRSEP(plist[plen - 1]))
  99                                 Xput(*xsp, xp, DIRSEP);
 100                         rval = 1;
 101                 }
 102         }
 103
 104         len = strlen(file) + 1;
 105         XcheckN(*xsp, xp, len);
 106         memcpy(xp, file, len);
 107
 108         if (!use_cdpath)
 109                 *cdpathp = (char *) 0;
 110
 111         return rval;
 112 }
 113
 114 /*
 115  * Simplify pathnames containing "." and ".." entries.
 116  * ie, simplify_path("/a/b/c/./../d/..") returns "/a/b"
 117  */
 118 void
 119 simplify_path(pathx)
 120         char    *pathx;
 121 {
 122         char    *cur;
 123         char    *t;
 124         int     isrooted;
 125         char    *very_start = pathx;
 126         char    *start;
 127
 128         if (!*pathx)
 129                 return;
 130
 131         if ((isrooted = ISROOTEDPATH(pathx)))
 132                 very_start++;
 133 #if defined (OS2) || defined (__CYGWIN__)
 134         if (pathx[0] && pathx[1] == ':')        /* skip a: */
 135                 very_start += 2;
 136 #endif /* OS2 || __CYGWIN__ */
 137
 138         /* Before                       After
 139          *  /foo/                       /foo
 140          *  /foo/../../bar              /bar
 141          *  /foo/./blah/..              /foo
 142          *  .                           .
 143          *  ..                          ..
 144          *  ./foo                       foo
 145          *  foo/../../../bar            ../../bar
 146          * OS2 and CYGWIN:
 147          *  a:/foo/../..                a:/
 148          *  a:.                         a:
 149          *  a:..                        a:..
 150          *  a:foo/../../blah            a:../blah
 151          */
 152
 153 #ifdef __CYGWIN__
 154        /* preserve leading double-slash on pathnames (for UNC paths) */
 155        if (pathx[0] && ISDIRSEP(pathx[0]) && pathx[1] && ISDIRSEP(pathx[1]))
 156                very_start++;
 157 #endif /* __CYGWIN__ */
 158
 159         for (cur = t = start = very_start; ; ) {
 160                 /* treat multiple '/'s as one '/' */
 161                 while (ISDIRSEP(*t))
 162                         t++;
 163
 164                 if (*t == '\0') {
 165                         if (cur == pathx)
 166                                 /* convert empty path to dot */
 167                                 *cur++ = '.';
 168                         *cur = '\0';
 169                         break;
 170                 }
 171
 172                 if (t[0] == '.') {
 173                         if (!t[1] || ISDIRSEP(t[1])) {
 174                                 t += 1;
 175                                 continue;
 176                         } else if (t[1] == '.' && (!t[2] || ISDIRSEP(t[2]))) {
 177                                 if (!isrooted && cur == start) {
 178                                         if (cur != very_start)
 179                                                 *cur++ = DIRSEP;
 180                                         *cur++ = '.';
 181                                         *cur++ = '.';
 182                                         start = cur;
 183                                 } else if (cur != start)
 184                                         while (--cur > start && !ISDIRSEP(*cur))
 185                                                 ;
 186                                 t += 2;
 187                                 continue;
 188                         }
 189                 }
 190
 191                 if (cur != very_start)
 192                         *cur++ = DIRSEP;
 193
 194                 /* find/copy next component of pathname */
 195                 while (*t && !ISDIRSEP(*t))
 196                         *cur++ = *t++;
 197         }
 198 }
 199
 200
 201 void
 202 set_current_wd(pathx)
 203         char *pathx;
 204 {
 205         int len;
 206         char *p = pathx;
 207
 208         if (!p && !(p = ksh_get_wd((char *) 0, 0)))
 209                 p = null;
 210
 211         len = strlen(p) + 1;
 212
 213         if (len > current_wd_size)
 214                 current_wd = aresize(current_wd, current_wd_size = len, APERM);
 215         memcpy(current_wd, p, len);
 216         if (p != pathx && p != null)
 217                 afree(p, ATEMP);
 218 }
 219
 220 #ifdef S_ISLNK
 221 char *
 222 get_phys_path(pathx)
 223         const char *pathx;
 224 {
 225         XString xs;
 226         char *xp;
 227
 228         Xinit(xs, xp, strlen(pathx) + 1, ATEMP);
 229
 230         xp = do_phys_path(&xs, xp, pathx);
 231
 232         if (!xp)
 233                 return (char *) 0;
 234
 235         if (Xlength(xs, xp) == 0)
 236                 Xput(xs, xp, DIRSEP);
 237         Xput(xs, xp, '\0');
 238
 239         return Xclose(xs, xp);
 240 }
 241
 242 static char *
 243 do_phys_path(xsp, xp, pathx)
 244         XString *xsp;
 245         char *xp;
 246         const char *pathx;
 247 {
 248         const char *p, *q;
 249         int len, llen;
 250         int savepos;
 251         char lbuf[PATH];
 252
 253         Xcheck(*xsp, xp);
 254         for (p = pathx; p; p = q) {
 255                 while (ISDIRSEP(*p))
 256                         p++;
 257                 if (!*p)
 258                         break;
 259                 len = (q = ksh_strchr_dirsep(p)) ? q - p : (int)strlen(p);
 260                 if (len == 1 && p[0] == '.')
 261                         continue;
 262                 if (len == 2 && p[0] == '.' && p[1] == '.') {
 263                         while (xp > Xstring(*xsp, xp)) {
 264                                 xp--;
 265                                 if (ISDIRSEP(*xp))
 266                                         break;
 267                         }
 268                         continue;
 269                 }
 270
 271                 savepos = Xsavepos(*xsp, xp);
 272                 Xput(*xsp, xp, DIRSEP);
 273                 XcheckN(*xsp, xp, len + 1);
 274                 memcpy(xp, p, len);
 275                 xp += len;
 276                 *xp = '\0';
 277
 278                 llen = readlink(Xstring(*xsp, xp), lbuf, sizeof(lbuf) - 1);
 279                 if (llen < 0) {
 280                         /* EINVAL means it wasn't a symlink... */
 281                         if (errno != EINVAL)
 282                                 return (char *) 0;
 283                         continue;
 284                 }
 285                 lbuf[llen] = '\0';
 286
 287                 /* If absolute path, start from scratch.. */
 288                 xp = ISABSPATH(lbuf) ? Xstring(*xsp, xp)
 289                                      : Xrestpos(*xsp, xp, savepos);
 290                 if (!(xp = do_phys_path(xsp, xp, lbuf)))
 291                         return (char *) 0;
 292         }
 293         return xp;
 294 }
 295 #endif /* S_ISLNK */
 296
 297 #ifdef  TEST
 298
 299 main(argc, argv)
 300 {
 301         int     rv;
 302         char    *cp, cdpath[256], pwd[256], file[256], result[256];
 303
 304         printf("enter CDPATH: "); gets(cdpath);
 305         printf("enter PWD: "); gets(pwd);
 306         while (1) {
 307                 if (printf("Enter file: "), gets(file) == 0)
 308                         return 0;
 309                 cp = cdpath;
 310                 do {
 311                         rv = make_path(pwd, file, &cp, result, sizeof(result));
 312                         printf("make_path returns (%d), \"%s\" ", rv, result);
 313                         simplify_path(result);
 314                         printf("(simpifies to \"%s\")\n", result);
 315                 } while (cp);
 316         }
 317 }
 318 #endif  /* TEST */