path.c revision 1.1.1.2
1 #include "sh.h" 2 #include "ksh_stat.h" 3 4 /* 5 * Contains a routine to search a : separated list of 6 * paths (a la CDPATH) and make appropiate file names. 7 * Also contains a routine to simplify .'s and ..'s out of 8 * a path name. 9 * 10 * Larry Bouzane (larry (at) cs.mun.ca) 11 */ 12 13 /* 14 * $Log: path.c,v $ 15 * Revision 1.1.1.2 1999/10/20 14:27:30 hubertf 16 * Import pdksh V5.2.14. 17 * Includes lots of bugfixes. 18 * 19 * Revision 1.2 1994/05/19 18:32:40 michael 20 * Merge complete, stdio replaced, various fixes. (pre autoconf) 21 * 22 * Revision 1.1 1994/04/06 13:14:03 michael 23 * Initial revision 24 * 25 * Revision 4.2 1990/12/06 18:05:24 larry 26 * Updated test code to reflect parameter change. 27 * Fixed problem with /a/./.dir being simplified to /a and not /a/.dir due 28 * to *(cur+2) == *f test instead of the correct cur+2 == f 29 * 30 * Revision 4.1 90/10/29 14:42:19 larry 31 * base MUN version 32 * 33 * Revision 3.1.0.4 89/02/16 20:28:36 larry 34 * Forgot to set *pathlist to NULL when last changed make_path(). 35 * 36 * Revision 3.1.0.3 89/02/13 20:29:55 larry 37 * Fixed up cd so that it knew when a node from CDPATH was used and would 38 * print a message only when really necessary. 39 * 40 * Revision 3.1.0.2 89/02/13 17:51:22 larry 41 * Merged with Eric Gisin's version. 42 * 43 * Revision 3.1.0.1 89/02/13 17:50:58 larry 44 * *** empty log message *** 45 * 46 * Revision 3.1 89/02/13 17:49:28 larry 47 * *** empty log message *** 48 * 49 */ 50 51 #ifdef S_ISLNK 52 static char *do_phys_path ARGS((XString *xsp, char *xp, const char *path)); 53 #endif /* S_ISLNK */ 54 55 /* 56 * Makes a filename into result using the following algorithm. 57 * - make result NULL 58 * - if file starts with '/', append file to result & set cdpathp to NULL 59 * - if file starts with ./ or ../ append cwd and file to result 60 * and set cdpathp to NULL 61 * - if the first element of cdpathp doesnt start with a '/' xx or '.' xx 62 * then cwd is appended to result. 63 * - the first element of cdpathp is appended to result 64 * - file is appended to result 65 * - cdpathp is set to the start of the next element in cdpathp (or NULL 66 * if there are no more elements. 67 * The return value indicates whether a non-null element from cdpathp 68 * was appened to result. 69 */ 70 int 71 make_path(cwd, file, cdpathp, xsp, phys_pathp) 72 const char *cwd; 73 const char *file; 74 char **cdpathp; /* & of : separated list */ 75 XString *xsp; 76 int *phys_pathp; 77 { 78 int rval = 0; 79 int use_cdpath = 1; 80 char *plist; 81 int len; 82 int plen = 0; 83 char *xp = Xstring(*xsp, xp); 84 85 if (!file) 86 file = null; 87 88 if (!ISRELPATH(file)) { 89 *phys_pathp = 0; 90 use_cdpath = 0; 91 } else { 92 if (file[0] == '.') { 93 char c = file[1]; 94 95 if (c == '.') 96 c = file[2]; 97 if (ISDIRSEP(c) || c == '\0') 98 use_cdpath = 0; 99 } 100 101 plist = *cdpathp; 102 if (!plist) 103 use_cdpath = 0; 104 else if (use_cdpath) { 105 char *pend; 106 107 for (pend = plist; *pend && *pend != PATHSEP; pend++) 108 ; 109 plen = pend - plist; 110 *cdpathp = *pend ? ++pend : (char *) 0; 111 } 112 113 if ((use_cdpath == 0 || !plen || ISRELPATH(plist)) 114 && (cwd && *cwd)) 115 { 116 len = strlen(cwd); 117 XcheckN(*xsp, xp, len); 118 memcpy(xp, cwd, len); 119 xp += len; 120 if (!ISDIRSEP(cwd[len - 1])) 121 Xput(*xsp, xp, DIRSEP); 122 } 123 *phys_pathp = Xlength(*xsp, xp); 124 if (use_cdpath && plen) { 125 XcheckN(*xsp, xp, plen); 126 memcpy(xp, plist, plen); 127 xp += plen; 128 if (!ISDIRSEP(plist[plen - 1])) 129 Xput(*xsp, xp, DIRSEP); 130 rval = 1; 131 } 132 } 133 134 len = strlen(file) + 1; 135 XcheckN(*xsp, xp, len); 136 memcpy(xp, file, len); 137 138 if (!use_cdpath) 139 *cdpathp = (char *) 0; 140 141 return rval; 142 } 143 144 /* 145 * Simplify pathnames containing "." and ".." entries. 146 * ie, simplify_path("/a/b/c/./../d/..") returns "/a/b" 147 */ 148 void 149 simplify_path(path) 150 char *path; 151 { 152 char *cur; 153 char *t; 154 int isrooted; 155 char *very_start = path; 156 char *start; 157 158 if (!*path) 159 return; 160 161 if ((isrooted = ISROOTEDPATH(path))) 162 very_start++; 163 #if defined (OS2) || defined (__CYGWIN__) 164 if (path[0] && path[1] == ':') /* skip a: */ 165 very_start += 2; 166 #endif /* OS2 || __CYGWIN__ */ 167 168 /* Before After 169 * /foo/ /foo 170 * /foo/../../bar /bar 171 * /foo/./blah/.. /foo 172 * . . 173 * .. .. 174 * ./foo foo 175 * foo/../../../bar ../../bar 176 * OS2 and CYGWIN: 177 * a:/foo/../.. a:/ 178 * a:. a: 179 * a:.. a:.. 180 * a:foo/../../blah a:../blah 181 */ 182 183 #ifdef __CYGWIN__ 184 /* preserve leading double-slash on pathnames (for UNC paths) */ 185 if (path[0] && ISDIRSEP(path[0]) && path[1] && ISDIRSEP(path[1])) 186 very_start++; 187 #endif /* __CYGWIN__ */ 188 189 for (cur = t = start = very_start; ; ) { 190 /* treat multiple '/'s as one '/' */ 191 while (ISDIRSEP(*t)) 192 t++; 193 194 if (*t == '\0') { 195 if (cur == path) 196 /* convert empty path to dot */ 197 *cur++ = '.'; 198 *cur = '\0'; 199 break; 200 } 201 202 if (t[0] == '.') { 203 if (!t[1] || ISDIRSEP(t[1])) { 204 t += 1; 205 continue; 206 } else if (t[1] == '.' && (!t[2] || ISDIRSEP(t[2]))) { 207 if (!isrooted && cur == start) { 208 if (cur != very_start) 209 *cur++ = DIRSEP; 210 *cur++ = '.'; 211 *cur++ = '.'; 212 start = cur; 213 } else if (cur != start) 214 while (--cur > start && !ISDIRSEP(*cur)) 215 ; 216 t += 2; 217 continue; 218 } 219 } 220 221 if (cur != very_start) 222 *cur++ = DIRSEP; 223 224 /* find/copy next component of pathname */ 225 while (*t && !ISDIRSEP(*t)) 226 *cur++ = *t++; 227 } 228 } 229 230 231 void 232 set_current_wd(path) 233 char *path; 234 { 235 int len; 236 char *p = path; 237 238 if (!p && !(p = ksh_get_wd((char *) 0, 0))) 239 p = null; 240 241 len = strlen(p) + 1; 242 243 if (len > current_wd_size) 244 current_wd = aresize(current_wd, current_wd_size = len, APERM); 245 memcpy(current_wd, p, len); 246 if (p != path && p != null) 247 afree(p, ATEMP); 248 } 249 250 #ifdef S_ISLNK 251 char * 252 get_phys_path(path) 253 const char *path; 254 { 255 XString xs; 256 char *xp; 257 258 Xinit(xs, xp, strlen(path) + 1, ATEMP); 259 260 xp = do_phys_path(&xs, xp, path); 261 262 if (!xp) 263 return (char *) 0; 264 265 if (Xlength(xs, xp) == 0) 266 Xput(xs, xp, DIRSEP); 267 Xput(xs, xp, '\0'); 268 269 return Xclose(xs, xp); 270 } 271 272 static char * 273 do_phys_path(xsp, xp, path) 274 XString *xsp; 275 char *xp; 276 const char *path; 277 { 278 const char *p, *q; 279 int len, llen; 280 int savepos; 281 char lbuf[PATH]; 282 283 Xcheck(*xsp, xp); 284 for (p = path; p; p = q) { 285 while (ISDIRSEP(*p)) 286 p++; 287 if (!*p) 288 break; 289 len = (q = ksh_strchr_dirsep(p)) ? q - p : strlen(p); 290 if (len == 1 && p[0] == '.') 291 continue; 292 if (len == 2 && p[0] == '.' && p[1] == '.') { 293 while (xp > Xstring(*xsp, xp)) { 294 xp--; 295 if (ISDIRSEP(*xp)) 296 break; 297 } 298 continue; 299 } 300 301 savepos = Xsavepos(*xsp, xp); 302 Xput(*xsp, xp, DIRSEP); 303 XcheckN(*xsp, xp, len + 1); 304 memcpy(xp, p, len); 305 xp += len; 306 *xp = '\0'; 307 308 llen = readlink(Xstring(*xsp, xp), lbuf, sizeof(lbuf) - 1); 309 if (llen < 0) { 310 /* EINVAL means it wasn't a symlink... */ 311 if (errno != EINVAL) 312 return (char *) 0; 313 continue; 314 } 315 lbuf[llen] = '\0'; 316 317 /* If absolute path, start from scratch.. */ 318 xp = ISABSPATH(lbuf) ? Xstring(*xsp, xp) 319 : Xrestpos(*xsp, xp, savepos); 320 if (!(xp = do_phys_path(xsp, xp, lbuf))) 321 return (char *) 0; 322 } 323 return xp; 324 } 325 #endif /* S_ISLNK */ 326 327 #ifdef TEST 328 329 main(argc, argv) 330 { 331 int rv; 332 char *cp, cdpath[256], pwd[256], file[256], result[256]; 333 334 printf("enter CDPATH: "); gets(cdpath); 335 printf("enter PWD: "); gets(pwd); 336 while (1) { 337 if (printf("Enter file: "), gets(file) == 0) 338 return 0; 339 cp = cdpath; 340 do { 341 rv = make_path(pwd, file, &cp, result, sizeof(result)); 342 printf("make_path returns (%d), \"%s\" ", rv, result); 343 simplify_path(result); 344 printf("(simpifies to \"%s\")\n", result); 345 } while (cp); 346 } 347 } 348 #endif /* TEST */ 349
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