1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate * CDDL HEADER START
3*0Sstevel@tonic-gate *
4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance
7*0Sstevel@tonic-gate * with the License.
8*0Sstevel@tonic-gate *
9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate * and limitations under the License.
13*0Sstevel@tonic-gate *
14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate *
20*0Sstevel@tonic-gate * CDDL HEADER END
21*0Sstevel@tonic-gate */
22*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI"
23*0Sstevel@tonic-gate
24*0Sstevel@tonic-gate /*
25*0Sstevel@tonic-gate * Copyright (c) 1987 by Sun Microsystems, Inc.
26*0Sstevel@tonic-gate */
27*0Sstevel@tonic-gate
28*0Sstevel@tonic-gate #include <strings.h>
29*0Sstevel@tonic-gate #include <sys/param.h>
30*0Sstevel@tonic-gate #include <errno.h>
31*0Sstevel@tonic-gate
32*0Sstevel@tonic-gate extern char *getwd();
33*0Sstevel@tonic-gate
34*0Sstevel@tonic-gate /* LINTLIBRARY */
35*0Sstevel@tonic-gate
36*0Sstevel@tonic-gate /*
37*0Sstevel@tonic-gate * Input name in raw, canonicalized pathname output to canon. If dosymlinks
38*0Sstevel@tonic-gate * is nonzero, resolves all symbolic links encountered during canonicalization
39*0Sstevel@tonic-gate * into an equivalent symlink-free form. Returns 0 on success, -1 on failure.
40*0Sstevel@tonic-gate * The routine fails if the current working directory can't be obtained or if
41*0Sstevel@tonic-gate * either of the arguments is NULL.
42*0Sstevel@tonic-gate *
43*0Sstevel@tonic-gate * Sets errno on failure.
44*0Sstevel@tonic-gate */
45*0Sstevel@tonic-gate int
pathcanon(raw,canon,dosymlinks)46*0Sstevel@tonic-gate pathcanon(raw, canon, dosymlinks)
47*0Sstevel@tonic-gate char *raw,
48*0Sstevel@tonic-gate *canon;
49*0Sstevel@tonic-gate int dosymlinks;
50*0Sstevel@tonic-gate {
51*0Sstevel@tonic-gate register char *s,
52*0Sstevel@tonic-gate *d;
53*0Sstevel@tonic-gate register char *limit = canon + MAXPATHLEN;
54*0Sstevel@tonic-gate char *modcanon;
55*0Sstevel@tonic-gate int nlink = 0;
56*0Sstevel@tonic-gate
57*0Sstevel@tonic-gate /*
58*0Sstevel@tonic-gate * Do a bit of sanity checking.
59*0Sstevel@tonic-gate */
60*0Sstevel@tonic-gate if (raw == NULL || canon == NULL) {
61*0Sstevel@tonic-gate errno = EINVAL;
62*0Sstevel@tonic-gate return (-1);
63*0Sstevel@tonic-gate }
64*0Sstevel@tonic-gate
65*0Sstevel@tonic-gate /*
66*0Sstevel@tonic-gate * If the path in raw is not already absolute, convert it to that form.
67*0Sstevel@tonic-gate * In any case, initialize canon with the absolute form of raw. Make
68*0Sstevel@tonic-gate * sure that none of the operations overflow the corresponding buffers.
69*0Sstevel@tonic-gate * The code below does the copy operations by hand so that it can easily
70*0Sstevel@tonic-gate * keep track of whether overflow is about to occur.
71*0Sstevel@tonic-gate */
72*0Sstevel@tonic-gate s = raw;
73*0Sstevel@tonic-gate d = canon;
74*0Sstevel@tonic-gate if (*s != '/') {
75*0Sstevel@tonic-gate /* Relative; prepend the working directory. */
76*0Sstevel@tonic-gate if (getwd(d) == NULL) {
77*0Sstevel@tonic-gate /* Use whatever errno value getwd may have left around. */
78*0Sstevel@tonic-gate return (-1);
79*0Sstevel@tonic-gate }
80*0Sstevel@tonic-gate d += strlen(d);
81*0Sstevel@tonic-gate /* Add slash to separate working directory from relative part. */
82*0Sstevel@tonic-gate if (d < limit)
83*0Sstevel@tonic-gate *d++ = '/';
84*0Sstevel@tonic-gate modcanon = d;
85*0Sstevel@tonic-gate } else
86*0Sstevel@tonic-gate modcanon = canon;
87*0Sstevel@tonic-gate while (d < limit && *s)
88*0Sstevel@tonic-gate *d++ = *s++;
89*0Sstevel@tonic-gate
90*0Sstevel@tonic-gate /* Add a trailing slash to simplify the code below. */
91*0Sstevel@tonic-gate s = "/";
92*0Sstevel@tonic-gate while (d < limit && (*d++ = *s++))
93*0Sstevel@tonic-gate continue;
94*0Sstevel@tonic-gate
95*0Sstevel@tonic-gate
96*0Sstevel@tonic-gate /*
97*0Sstevel@tonic-gate * Canonicalize the path. The strategy is to update in place, with
98*0Sstevel@tonic-gate * d pointing to the end of the canonicalized portion and s to the
99*0Sstevel@tonic-gate * current spot from which we're copying. This works because
100*0Sstevel@tonic-gate * canonicalization doesn't increase path length, except as discussed
101*0Sstevel@tonic-gate * below. Note also that the path has had a slash added at its end.
102*0Sstevel@tonic-gate * This greatly simplifies the treatment of boundary conditions.
103*0Sstevel@tonic-gate */
104*0Sstevel@tonic-gate d = s = modcanon;
105*0Sstevel@tonic-gate while (d < limit && *s) {
106*0Sstevel@tonic-gate if ((*d++ = *s++) == '/' && d > canon + 1) {
107*0Sstevel@tonic-gate register char *t = d - 2;
108*0Sstevel@tonic-gate
109*0Sstevel@tonic-gate switch (*t) {
110*0Sstevel@tonic-gate case '/':
111*0Sstevel@tonic-gate /* Found // in the name. */
112*0Sstevel@tonic-gate d--;
113*0Sstevel@tonic-gate continue;
114*0Sstevel@tonic-gate case '.':
115*0Sstevel@tonic-gate switch (*--t) {
116*0Sstevel@tonic-gate case '/':
117*0Sstevel@tonic-gate /* Found /./ in the name. */
118*0Sstevel@tonic-gate d -= 2;
119*0Sstevel@tonic-gate continue;
120*0Sstevel@tonic-gate case '.':
121*0Sstevel@tonic-gate if (*--t == '/') {
122*0Sstevel@tonic-gate /* Found /../ in the name. */
123*0Sstevel@tonic-gate while (t > canon && *--t != '/')
124*0Sstevel@tonic-gate continue;
125*0Sstevel@tonic-gate d = t + 1;
126*0Sstevel@tonic-gate }
127*0Sstevel@tonic-gate continue;
128*0Sstevel@tonic-gate default:
129*0Sstevel@tonic-gate break;
130*0Sstevel@tonic-gate }
131*0Sstevel@tonic-gate break;
132*0Sstevel@tonic-gate default:
133*0Sstevel@tonic-gate break;
134*0Sstevel@tonic-gate }
135*0Sstevel@tonic-gate /*
136*0Sstevel@tonic-gate * We're at the end of a component. If dosymlinks is set
137*0Sstevel@tonic-gate * see whether the component is a symbolic link. If so,
138*0Sstevel@tonic-gate * replace it by its contents.
139*0Sstevel@tonic-gate */
140*0Sstevel@tonic-gate if (dosymlinks) {
141*0Sstevel@tonic-gate char link[MAXPATHLEN + 1];
142*0Sstevel@tonic-gate register int llen;
143*0Sstevel@tonic-gate
144*0Sstevel@tonic-gate /*
145*0Sstevel@tonic-gate * See whether it's a symlink by trying to read it.
146*0Sstevel@tonic-gate *
147*0Sstevel@tonic-gate * Start by isolating it.
148*0Sstevel@tonic-gate */
149*0Sstevel@tonic-gate *(d - 1) = '\0';
150*0Sstevel@tonic-gate if ((llen = readlink(canon, link, sizeof link)) >= 0) {
151*0Sstevel@tonic-gate /* Make sure that there are no circular links. */
152*0Sstevel@tonic-gate nlink++;
153*0Sstevel@tonic-gate if (nlink > MAXSYMLINKS) {
154*0Sstevel@tonic-gate errno = ELOOP;
155*0Sstevel@tonic-gate return (-1);
156*0Sstevel@tonic-gate }
157*0Sstevel@tonic-gate /*
158*0Sstevel@tonic-gate * The component is a symlink. Since its value can be
159*0Sstevel@tonic-gate * of arbitrary size, we can't continue copying in place.
160*0Sstevel@tonic-gate * Instead, form the new path suffix in the link buffer
161*0Sstevel@tonic-gate * and then copy it back to its proper spot in canon.
162*0Sstevel@tonic-gate */
163*0Sstevel@tonic-gate t = link + llen;
164*0Sstevel@tonic-gate *t++ = '/';
165*0Sstevel@tonic-gate /*
166*0Sstevel@tonic-gate * Copy the remaining unresolved portion to the end
167*0Sstevel@tonic-gate * of the symlink. If the sum of the unresolved part and
168*0Sstevel@tonic-gate * the readlink exceeds MAXPATHLEN, the extra bytes
169*0Sstevel@tonic-gate * will be dropped off. Too bad!
170*0Sstevel@tonic-gate */
171*0Sstevel@tonic-gate (void) strncpy(t, s, sizeof link - llen - 1);
172*0Sstevel@tonic-gate link[sizeof link - 1] = '\0';
173*0Sstevel@tonic-gate /*
174*0Sstevel@tonic-gate * If the link's contents are absolute, copy it back
175*0Sstevel@tonic-gate * to the start of canon, otherwise to the beginning of
176*0Sstevel@tonic-gate * the link's position in the path.
177*0Sstevel@tonic-gate */
178*0Sstevel@tonic-gate if (link[0] == '/') {
179*0Sstevel@tonic-gate /* Absolute. */
180*0Sstevel@tonic-gate (void) strcpy(canon, link);
181*0Sstevel@tonic-gate d = s = canon;
182*0Sstevel@tonic-gate }
183*0Sstevel@tonic-gate else {
184*0Sstevel@tonic-gate /*
185*0Sstevel@tonic-gate * Relative: find beginning of component and copy.
186*0Sstevel@tonic-gate */
187*0Sstevel@tonic-gate --d;
188*0Sstevel@tonic-gate while (d > canon && *--d != '/')
189*0Sstevel@tonic-gate continue;
190*0Sstevel@tonic-gate s = ++d;
191*0Sstevel@tonic-gate /*
192*0Sstevel@tonic-gate * If the sum of the resolved part, the readlink
193*0Sstevel@tonic-gate * and the remaining unresolved part exceeds
194*0Sstevel@tonic-gate * MAXPATHLEN, the extra bytes will be dropped off.
195*0Sstevel@tonic-gate */
196*0Sstevel@tonic-gate if (strlen(link) >= (limit - s)) {
197*0Sstevel@tonic-gate (void) strncpy(s, link, limit - s);
198*0Sstevel@tonic-gate *(limit - 1) = '\0';
199*0Sstevel@tonic-gate } else {
200*0Sstevel@tonic-gate (void) strcpy(s, link);
201*0Sstevel@tonic-gate }
202*0Sstevel@tonic-gate }
203*0Sstevel@tonic-gate continue;
204*0Sstevel@tonic-gate } else {
205*0Sstevel@tonic-gate /*
206*0Sstevel@tonic-gate * readlink call failed. It can be because it was
207*0Sstevel@tonic-gate * not a link (i.e. a file, dir etc.) or because the
208*0Sstevel@tonic-gate * the call actually failed.
209*0Sstevel@tonic-gate */
210*0Sstevel@tonic-gate if (errno != EINVAL)
211*0Sstevel@tonic-gate return (-1);
212*0Sstevel@tonic-gate *(d - 1) = '/'; /* Restore it */
213*0Sstevel@tonic-gate }
214*0Sstevel@tonic-gate } /* if (dosymlinks) */
215*0Sstevel@tonic-gate }
216*0Sstevel@tonic-gate } /* while */
217*0Sstevel@tonic-gate
218*0Sstevel@tonic-gate /* Remove the trailing slash that was added above. */
219*0Sstevel@tonic-gate if (*(d - 1) == '/' && d > canon + 1)
220*0Sstevel@tonic-gate d--;
221*0Sstevel@tonic-gate *d = '\0';
222*0Sstevel@tonic-gate return (0);
223*0Sstevel@tonic-gate }
224*0Sstevel@tonic-gate
225*0Sstevel@tonic-gate /*
226*0Sstevel@tonic-gate * Canonicalize the path given in raw, resolving away all symbolic link
227*0Sstevel@tonic-gate * components. Store the result into the buffer named by canon, which
228*0Sstevel@tonic-gate * must be long enough (MAXPATHLEN bytes will suffice). Returns NULL
229*0Sstevel@tonic-gate * on failure and canon on success.
230*0Sstevel@tonic-gate *
231*0Sstevel@tonic-gate * The routine indirectly invokes the readlink() system call and getwd()
232*0Sstevel@tonic-gate * so it inherits the possibility of hanging due to inaccessible file
233*0Sstevel@tonic-gate * system resources.
234*0Sstevel@tonic-gate */
235*0Sstevel@tonic-gate char *
realpath(raw,canon)236*0Sstevel@tonic-gate realpath(raw, canon)
237*0Sstevel@tonic-gate char *raw;
238*0Sstevel@tonic-gate char *canon;
239*0Sstevel@tonic-gate {
240*0Sstevel@tonic-gate return (pathcanon(raw, canon, 1) < 0 ? NULL : canon);
241*0Sstevel@tonic-gate }
242