--- realpath.c.orig 2003-08-15 19:22:17.000000000 -0700
+++ realpath.c 2004-12-04 14:47:52.000000000 -0800
@@ -35,13 +35,35 @@
#include "namespace.h"
#include <sys/param.h>
#include <sys/stat.h>
+#include <sys/mount.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
+#include <sys/attr.h>
+#include <sys/vnode.h>
#include "un-namespace.h"
+struct attrs {
+ u_int32_t len;
+ attrreference_t name;
+ dev_t dev;
+ fsobj_type_t type;
+ fsobj_id_t id;
+ char buf[PATH_MAX];
+};
+
+static struct attrlist alist = {
+ ATTR_BIT_MAP_COUNT,
+ 0,
+ ATTR_CMN_NAME | ATTR_CMN_DEVID | ATTR_CMN_OBJTYPE | ATTR_CMN_OBJID,
+ 0,
+ 0,
+ 0,
+ 0,
+};
+
/*
* char *realpath(const char *path, char resolved[PATH_MAX]);
*
@@ -52,13 +74,25 @@
char *
realpath(const char *path, char resolved[PATH_MAX])
{
+ struct attrs attrs;
struct stat sb;
char *p, *q, *s;
- size_t left_len, resolved_len;
+ size_t left_len, resolved_len, save_resolved_len;
unsigned symlinks;
- int serrno, slen;
+ int serrno, slen, useattrs, islink;
char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
+ dev_t dev, lastdev;
+ struct statfs sfs;
+ static dev_t rootdev;
+ static int rootdev_inited = 0;
+ ino_t inode;
+ if (!rootdev_inited) {
+ rootdev_inited = 1;
+ if (stat("/", &sb) < 0)
+ return (NULL);
+ rootdev = sb.st_dev;
+ }
serrno = errno;
symlinks = 0;
if (path[0] == '/') {
@@ -80,6 +114,12 @@
errno = ENAMETOOLONG;
return (NULL);
}
+ if (resolved_len > 1) {
+ if (stat(resolved, &sb) < 0)
+ return (NULL);
+ lastdev = sb.st_dev;
+ } else
+ lastdev = rootdev;
/*
* Iterate over path components in `left'.
@@ -127,6 +167,13 @@
}
/*
+ * Save resolved_len, so that we can later null out
+ * the the appended next_token, and replace with the
+ * real name (matters on case-insensitive filesystems).
+ */
+ save_resolved_len = resolved_len;
+
+ /*
* Append the next path component and lstat() it. If
* lstat() fails we still can return successfully if
* there are no more path components left.
@@ -136,14 +183,72 @@
errno = ENAMETOOLONG;
return (NULL);
}
- if (lstat(resolved, &sb) != 0) {
+ if (getattrlist(resolved, &alist, &attrs, sizeof(attrs), FSOPT_NOFOLLOW) == 0) {
+ useattrs = 1;
+ islink = (attrs.type == VLNK);
+ dev = attrs.dev;
+ inode = attrs.id.fid_objno;
+ } else if (errno == EOPNOTSUPP || errno == EINVAL) {
+ if ((useattrs = lstat(resolved, &sb)) == 0) {
+ islink = S_ISLNK(sb.st_mode);
+ dev = sb.st_dev;
+ inode = sb.st_ino;
+ }
+ } else
+ useattrs = -1;
+ if (useattrs < 0) {
if (errno == ENOENT && p == NULL) {
errno = serrno;
return (resolved);
}
return (NULL);
}
- if (S_ISLNK(sb.st_mode)) {
+ if (dev != lastdev) {
+ /*
+ * We have crossed a mountpoint. For volumes like UDF
+ * the getattrlist name may not match the actual
+ * mountpoint, so we just copy the mountpoint directly.
+ * (3703138). However, the mountpoint may not be
+ * accessible, as when chroot-ed, so check first.
+ * There may be a file on the chroot-ed volume with
+ * the same name as the mountpoint, so compare device
+ * and inode numbers.
+ */
+ lastdev = dev;
+ if (statfs(resolved, &sfs) == 0 && lstat(sfs.f_mntonname, &sb) == 0 && dev == sb.st_dev && inode == sb.st_ino) {
+ /*
+ * However, it's possible that the mountpoint
+ * path matches, even though it isn't the real
+ * path in the chroot-ed environment, so check
+ * that each component of the mountpoint
+ * is a directory (and not a symlink)
+ */
+ char temp[MNAMELEN];
+ char *cp;
+ int ok = 1;
+
+ strcpy(temp, sfs.f_mntonname);
+ for(;;) {
+ if ((cp = strrchr(temp, '/')) == NULL) {
+ ok = 0;
+ break;
+ }
+ if (cp <= temp)
+ break;
+ *cp = 0;
+ if (lstat(temp, &sb) < 0 || (sb.st_mode & S_IFMT) != S_IFDIR) {
+ ok = 0;
+ break;
+ }
+ }
+ if (ok) {
+ resolved_len = strlcpy(resolved, sfs.f_mntonname, PATH_MAX);
+ continue;
+ }
+ }
+ /* if we fail, use the other methods. */
+ }
+ if (islink) {
if (symlinks++ > MAXSYMLINKS) {
errno = ELOOP;
return (NULL);
@@ -155,6 +260,7 @@
if (symlink[0] == '/') {
resolved[1] = 0;
resolved_len = 1;
+ lastdev = rootdev;
} else if (resolved_len > 1) {
/* Strip the last path component. */
resolved[resolved_len - 1] = '\0';
@@ -184,7 +290,30 @@
}
}
left_len = strlcpy(left, symlink, sizeof(left));
+ } else if (useattrs) {
+ /*
+ * attrs already has the real name.
+ */
+
+ resolved[save_resolved_len] = '\0';
+ resolved_len = strlcat(resolved, (const char *)&attrs.name + attrs.name.attr_dataoffset, PATH_MAX);
+ if (resolved_len >= PATH_MAX) {
+ errno = ENAMETOOLONG;
+ return (NULL);
+ }
}
+ /*
+ * For the case of useattrs == 0, we could scan the directory
+ * and try to match the inode. There are many problems with
+ * this: (1) the directory may not be readable, (2) for multiple
+ * hard links, we would find the first, but not necessarily
+ * the one specified in the path, (3) we can't try to do
+ * a case-insensitive search to match the right one in (2),
+ * because the underlying filesystem may do things like
+ * decompose composed characters. For most cases, doing
+ * nothing is the right thing when useattrs == 0, so we punt
+ * for now.
+ */
}
/*