1 /* from 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)
37 #include <sys/param.h>
48 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
49 (dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
52 getcwd(char *pt, size_t size)
63 size_t ptsize, upsize;
68 * If no buffer specified by the user, allocate one as necessary.
69 * If a buffer is specified, the size has to be non-zero. The path
70 * is built from the end of the buffer backwards.
80 if ((pt = malloc(ptsize = MAXPATHLEN)) == NULL)
88 * Allocate bytes for the string of "../"'s.
89 * Should always be enough (it's 340 levels). If it's not, allocate
90 * as necessary. Special * case the first stat, it's ".", not "..".
92 if ((up = malloc(upsize = MAXPATHLEN)) == NULL)
99 /* Save root values, so know when to stop. */
105 errno = 0; /* XXX readdir has no error return. */
107 for (first = 1;; first = 0) {
108 /* Stat the current level. */
112 /* Save current node values. */
116 /* Check for reaching root. */
117 if (root_dev == dev && root_ino == ino) {
120 * It's unclear that it's a requirement to copy the
121 * path to the beginning of the buffer, but it's always
122 * been that way and stuff would probably break.
124 memmove(pt, bpt, ept - bpt);
130 * Build pointer to the parent directory, allocating memory
131 * as necessary. Max length is 3 for "../", the largest
132 * possible component name, plus a trailing NUL.
134 if (bup + 3 + MAXNAMLEN + 1 >= eup) {
137 if ((nup = realloc(up, upsize *= 2)) == NULL)
139 bup = nup + (bup - up);
147 /* Open and stat parent directory. */
148 if (!(dir = opendir(up)) || fstat(dirfd(dir), &s))
151 /* Add trailing slash for next directory. */
155 * If it's a mount point, have to stat each element because
156 * the inode number in the directory is for the entry in the
157 * parent directory, not the inode number of the mounted file.
160 if (s.st_dev == dev) {
162 if (!(dp = readdir(dir)))
164 if (dp->d_fileno == ino)
169 if (!(dp = readdir(dir)))
173 memcpy(bup, dp->d_name, dp->d_namlen + 1);
175 /* Save the first error for later. */
182 if (s.st_dev == dev && s.st_ino == ino)
187 * Check for length of the current name, preceding slash,
190 if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) {
199 if ((npt = realloc(pt, ptsize *= 2)) == NULL)
201 bpt = npt + (bpt - pt);
204 memmove(ept - len, bpt, len);
210 memcpy(bpt, dp->d_name, dp->d_namlen);
213 /* Truncate any file name. */
219 * If readdir set errno, use it, not any saved error; otherwise,
220 * didn't find the current directory in its parent directory, set
224 errno = save_errno ? save_errno : ENOENT;
240 #endif /* !defined(HAVE_GETCWD) */