1 /* $OpenBSD: getcwd.c,v 1.14 2005/08/08 08:05:34 espie Exp */
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31 /* OPENBSD ORIGINAL: lib/libc/gen/getcwd.c */
35 #if !defined(HAVE_GETCWD)
47 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
48 (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
51 getcwd(char *pt, size_t size)
62 size_t ptsize, upsize;
67 * If no buffer specified by the user, allocate one as necessary.
68 * If a buffer is specified, the size has to be non-zero. The path
69 * is built from the end of the buffer backwards.
79 if ((pt = malloc(ptsize = MAXPATHLEN)) == NULL)
87 * Allocate bytes for the string of "../"'s.
88 * Should always be enough (it's 340 levels). If it's not, allocate
89 * as necessary. Special * case the first stat, it's ".", not "..".
91 if ((up = malloc(upsize = MAXPATHLEN)) == NULL)
98 /* Save root values, so know when to stop. */
104 errno = 0; /* XXX readdir has no error return. */
106 for (first = 1;; first = 0) {
107 /* Stat the current level. */
111 /* Save current node values. */
115 /* Check for reaching root. */
116 if (root_dev == dev && root_ino == ino) {
119 * It's unclear that it's a requirement to copy the
120 * path to the beginning of the buffer, but it's always
121 * been that way and stuff would probably break.
123 memmove(pt, bpt, ept - bpt);
129 * Build pointer to the parent directory, allocating memory
130 * as necessary. Max length is 3 for "../", the largest
131 * possible component name, plus a trailing NUL.
133 if (bup + 3 + MAXNAMLEN + 1 >= eup) {
136 if ((nup = realloc(up, upsize *= 2)) == NULL)
138 bup = nup + (bup - up);
146 /* Open and stat parent directory. */
147 if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
150 /* Add trailing slash for next directory. */
154 * If it's a mount point, have to stat each element because
155 * the inode number in the directory is for the entry in the
156 * parent directory, not the inode number of the mounted file.
159 if (s.st_dev == dev) {
161 if (!(dp = readdir(dir)))
163 if (dp->d_fileno == ino)
168 if (!(dp = readdir(dir)))
172 memcpy(bup, dp->d_name, dp->d_namlen + 1);
174 /* Save the first error for later. */
181 if (s.st_dev == dev && s.st_ino == ino)
186 * Check for length of the current name, preceding slash,
189 if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) {
198 if ((npt = realloc(pt, ptsize *= 2)) == NULL)
200 bpt = npt + (bpt - pt);
203 memmove(ept - len, bpt, len);
209 memcpy(bpt, dp->d_name, dp->d_namlen);
212 /* Truncate any file name. */
218 * If readdir set errno, use it, not any saved error; otherwise,
219 * didn't find the current directory in its parent directory, set
223 errno = save_errno ? save_errno : ENOENT;
239 #endif /* !defined(HAVE_GETCWD) */