--- getcwd.c.orig 2006-01-19 18:35:45.000000000 -0800
+++ getcwd.c 2006-02-08 17:53:41.000000000 -0800
@@ -54,7 +54,81 @@
(dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \
(dp->d_name[1] == '.' && dp->d_name[2] == '\0')))
-extern int __getcwd(char *, size_t);
+/*
+ * If __getcwd() ever becomes a syscall, we can remove this workaround.
+ * The problem here is that fcntl() assumes a buffer of size MAXPATHLEN,
+ * if size is less than MAXPATHLEN, we need to use a temporary buffer
+ * and see if it fits. We also have to assume that open() or fcntl()
+ * don't fail with errno=ERANGE.
+ */
+static inline int
+__getcwd(char *buf, size_t size)
+{
+ int fd, err, save;
+ struct stat dot, pt;
+ char *b;
+
+ if ((fd = open(".", O_RDONLY)) < 0)
+ return -1;
+ if (fstat(fd, &dot) < 0) {
+ save = errno;
+ close(fd);
+ errno = save;
+ return -1;
+ }
+ /* check that the device and inode are non-zero, otherwise punt */
+ if (dot.st_dev == 0 || dot.st_ino == 0) {
+ close(fd);
+ errno = EINVAL;
+ return -1;
+ }
+ if (size < MAXPATHLEN) {
+ /* the hard case; allocate a buffer of size MAXPATHLEN to use */
+ b = (char *)alloca(MAXPATHLEN);
+ if (b == NULL) {
+ close(fd);
+ errno = ENOMEM; /* make sure it isn't ERANGE */
+ return -1;
+ }
+ } else
+ b = buf;
+
+ err = fcntl(fd, F_GETPATH, b);
+ if (err) {
+ save = errno;
+ close(fd);
+ errno = save;
+ return err;
+ }
+ close(fd);
+ /*
+ * now double-check that the path returned by fcntl() has the same
+ * device and inode number as '.'.
+ */
+ if (stat(b, &pt) < 0)
+ return -1;
+ /*
+ * Since dot.st_dev and dot.st_ino are non-zero, we don't need to
+ * separately test for pt.st_dev and pt.st_ino being non-zero, because
+ * they have to match
+ */
+ if (dot.st_dev != pt.st_dev || dot.st_ino != pt.st_ino) {
+ errno = EINVAL;
+ return -1;
+ }
+ /*
+ * For the case where we allocated a buffer, check that it can fit
+ * in the real buffer, and copy it over.
+ */
+ if (size < MAXPATHLEN) {
+ if (strlen(b) >= size) {
+ errno = ERANGE;
+ return -1;
+ }
+ strcpy(buf, b);
+ }
+ return 0;
+}
char *
getcwd(pt, size)
@@ -91,31 +165,23 @@
}
ept = pt + size;
} else {
- if ((pt = malloc(ptsize = 1024 - 4)) == NULL)
+ if ((pt = malloc(ptsize = MAXPATHLEN)) == NULL)
return (NULL);
ept = pt + ptsize;
}
if (__getcwd(pt, ept - pt) == 0) {
- if (*pt != '/') {
- bpt = pt;
- ept = pt + strlen(pt) - 1;
- while (bpt < ept) {
- c = *bpt;
- *bpt++ = *ept;
- *ept-- = c;
- }
- }
return (pt);
- }
+ } else if (errno == ERANGE) /* failed because buffer too small */
+ return NULL;
bpt = ept - 1;
*bpt = '\0';
/*
- * Allocate bytes (1024 - malloc space) for the string of "../"'s.
+ * Allocate bytes MAXPATHLEN) for the string of "../"'s.
* Should always be enough (it's 340 levels). If it's not, allocate
* as necessary. Special case the first stat, it's ".", not "..".
*/
- if ((up = malloc(upsize = 1024 - 4)) == NULL)
+ if ((up = malloc(upsize = MAXPATHLEN)) == NULL)
goto err;
eup = up + MAXPATHLEN;
bup = up;