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29 * $OpenBSD: realpath.c,v 1.7 2002/05/24 21:22:37 deraadt Exp $
34 #if !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH)
36 #include <sys/param.h>
53 * char *realpath(const char *path, char resolved_path[MAXPATHLEN]);
55 * Find the real name of path, by removing all ".", ".." and symlink
56 * components. Returns (resolved) on success, or (NULL) on failure,
57 * in which case the path which caused trouble is left in (resolved).
60 realpath(const char *path, char *resolved)
63 int fd, n, rootd, serrno = 0;
64 char *p, *q, wbuf[MAXPATHLEN], start[MAXPATHLEN];
67 /* Save the starting point. */
68 getcwd(start,MAXPATHLEN);
69 if ((fd = open(".", O_RDONLY)) < 0) {
70 (void)strlcpy(resolved, ".", MAXPATHLEN);
75 /* Convert "." -> "" to optimize away a needless lstat() and chdir() */
76 if (path[0] == '.' && path[1] == '\0')
80 * Find the dirname and basename from the path to be resolved.
81 * Change directory to the dirname component.
82 * lstat the basename part.
83 * if it is a symlink, read in the value and loop.
84 * if it is a directory, then change to that directory.
85 * get the current directory name and append the basename.
87 strlcpy(resolved, path, MAXPATHLEN);
89 q = strrchr(resolved, '/');
97 } while (q > resolved && *q == '/');
106 /* Deal with the last component. */
107 if (*p != '\0' && lstat(p, &sb) == 0) {
108 if (S_ISLNK(sb.st_mode)) {
109 if (++symlinks > MAXSYMLINKS) {
113 n = readlink(p, resolved, MAXPATHLEN-1);
119 if (S_ISDIR(sb.st_mode)) {
127 * Save the last component name and get the full pathname of
128 * the current directory.
130 (void)strlcpy(wbuf, p, sizeof wbuf);
131 if (getcwd(resolved, MAXPATHLEN) == 0)
135 * Join the two strings together, ensuring that the right thing
136 * happens if the last component is empty, or the dirname is root.
138 if (resolved[0] == '/' && resolved[1] == '\0')
144 if (strlen(resolved) + strlen(wbuf) + rootd + 1 > MAXPATHLEN) {
145 serrno = ENAMETOOLONG;
149 (void)strcat(resolved, "/");
150 (void)strcat(resolved, wbuf);
153 /* Go back to where we came from. */
154 if (chdir(start) < 0) {
161 err2: errno = serrno;
164 #endif /* !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH) */