1 /* $NetBSD: path.c,v 1.14 2022/10/31 21:22:05 andvar Exp $ */
2 #include <sys/cdefs.h>
3
4 #ifndef lint
5 __RCSID("$NetBSD: path.c,v 1.14 2022/10/31 21:22:05 andvar Exp $");
6 #endif
7
8 #include <sys/stat.h>
9
10 #include "sh.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
make_path(cwd,file,cdpathp,xsp,phys_pathp)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
simplify_path(pathx)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
134 /* Before After
135 * /foo/ /foo
136 * /foo/../../bar /bar
137 * /foo/./blah/.. /foo
138 * . .
139 * .. ..
140 * ./foo foo
141 * foo/../../../bar ../../bar
142 */
143
144 for (cur = t = start = very_start; ; ) {
145 /* treat multiple '/'s as one '/' */
146 while (ISDIRSEP(*t))
147 t++;
148
149 if (*t == '\0') {
150 if (cur == pathx)
151 /* convert empty path to dot */
152 *cur++ = '.';
153 *cur = '\0';
154 break;
155 }
156
157 if (t[0] == '.') {
158 if (!t[1] || ISDIRSEP(t[1])) {
159 t += 1;
160 continue;
161 } else if (t[1] == '.' && (!t[2] || ISDIRSEP(t[2]))) {
162 if (!isrooted && cur == start) {
163 if (cur != very_start)
164 *cur++ = DIRSEP;
165 *cur++ = '.';
166 *cur++ = '.';
167 start = cur;
168 } else if (cur != start)
169 while (--cur > start && !ISDIRSEP(*cur))
170 ;
171 t += 2;
172 continue;
173 }
174 }
175
176 if (cur != very_start)
177 *cur++ = DIRSEP;
178
179 /* find/copy next component of pathname */
180 while (*t && !ISDIRSEP(*t))
181 *cur++ = *t++;
182 }
183 }
184
185
186 void
set_current_wd(pathx)187 set_current_wd(pathx)
188 char *pathx;
189 {
190 int len;
191 char *p = pathx;
192
193 if (!p && !(p = ksh_get_wd((char *) 0, 0)))
194 p = null;
195
196 len = strlen(p) + 1;
197
198 if (len > current_wd_size)
199 current_wd = aresize(current_wd, current_wd_size = len, APERM);
200 memcpy(current_wd, p, len);
201 if (p != pathx && p != null)
202 afree(p, ATEMP);
203 }
204
205 #ifdef S_ISLNK
206 char *
get_phys_path(pathx)207 get_phys_path(pathx)
208 const char *pathx;
209 {
210 XString xs;
211 char *xp;
212
213 Xinit(xs, xp, strlen(pathx) + 1, ATEMP);
214
215 xp = do_phys_path(&xs, xp, pathx);
216
217 if (!xp)
218 return (char *) 0;
219
220 if (Xlength(xs, xp) == 0)
221 Xput(xs, xp, DIRSEP);
222 Xput(xs, xp, '\0');
223
224 return Xclose(xs, xp);
225 }
226
227 static char *
do_phys_path(xsp,xp,pathx)228 do_phys_path(xsp, xp, pathx)
229 XString *xsp;
230 char *xp;
231 const char *pathx;
232 {
233 const char *p, *q;
234 int len, llen;
235 int savepos;
236 char lbuf[PATH];
237
238 Xcheck(*xsp, xp);
239 for (p = pathx; p; p = q) {
240 while (ISDIRSEP(*p))
241 p++;
242 if (!*p)
243 break;
244 len = (q = ksh_strchr_dirsep(p)) ? q - p : (int)strlen(p);
245 if (len == 1 && p[0] == '.')
246 continue;
247 if (len == 2 && p[0] == '.' && p[1] == '.') {
248 while (xp > Xstring(*xsp, xp)) {
249 xp--;
250 if (ISDIRSEP(*xp))
251 break;
252 }
253 continue;
254 }
255
256 savepos = Xsavepos(*xsp, xp);
257 Xput(*xsp, xp, DIRSEP);
258 XcheckN(*xsp, xp, len + 1);
259 memcpy(xp, p, len);
260 xp += len;
261 *xp = '\0';
262
263 llen = readlink(Xstring(*xsp, xp), lbuf, sizeof(lbuf) - 1);
264 if (llen < 0) {
265 /* EINVAL means it wasn't a symlink... */
266 if (errno != EINVAL)
267 return (char *) 0;
268 continue;
269 }
270 lbuf[llen] = '\0';
271
272 /* If absolute path, start from scratch.. */
273 xp = ISABSPATH(lbuf) ? Xstring(*xsp, xp)
274 : Xrestpos(*xsp, xp, savepos);
275 if (!(xp = do_phys_path(xsp, xp, lbuf)))
276 return (char *) 0;
277 }
278 return xp;
279 }
280 #endif /* S_ISLNK */
281
282 #ifdef TEST
283
main(argc,argv)284 main(argc, argv)
285 {
286 int rv;
287 char *cp, cdpath[256], pwd[256], file[256], result[256];
288
289 printf("enter CDPATH: "); gets(cdpath);
290 printf("enter PWD: "); gets(pwd);
291 while (1) {
292 if (printf("Enter file: "), gets(file) == 0)
293 return 0;
294 cp = cdpath;
295 do {
296 rv = make_path(pwd, file, &cp, result, sizeof(result));
297 printf("make_path returns (%d), \"%s\" ", rv, result);
298 simplify_path(result);
299 printf("(simplifies to \"%s\")\n", result);
300 } while (cp);
301 }
302 }
303 #endif /* TEST */
304