--- realpath.c.orig 2008-04-04 14:39:39.000000000 -0700
+++ realpath.c 2008-04-04 19:59:19.000000000 -0700
@@ -35,13 +35,41 @@ __FBSDID("$FreeBSD: src/lib/libc/stdlib/
#include "namespace.h"
#include <sys/param.h>
#include <sys/stat.h>
+#include <sys/mount.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
+#include <sys/attr.h>
+#include <sys/vnode.h>
#include "un-namespace.h"
+struct attrs {
+ u_int32_t len;
+ attrreference_t name;
+ dev_t dev;
+ fsobj_type_t type;
+ fsobj_id_t id;
+ char buf[PATH_MAX];
+};
+
+#ifndef BUILDING_VARIANT
+__private_extern__ struct attrlist _rp_alist = {
+ ATTR_BIT_MAP_COUNT,
+ 0,
+ ATTR_CMN_NAME | ATTR_CMN_DEVID | ATTR_CMN_OBJTYPE | ATTR_CMN_OBJID,
+ 0,
+ 0,
+ 0,
+ 0,
+};
+#else /* BUILDING_VARIANT */
+__private_extern__ struct attrlist _rp_alist;
+#endif /* BUILDING_VARIANT */
+
+extern char * __private_getcwd(char *, size_t, int);
+
/*
* char *realpath(const char *path, char resolved[PATH_MAX]);
*
@@ -50,26 +78,67 @@ __FBSDID("$FreeBSD: src/lib/libc/stdlib/
* in which case the path which caused trouble is left in (resolved).
*/
char *
-realpath(const char *path, char resolved[PATH_MAX])
+realpath(const char *path, char inresolved[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;
+ char *resolved;
+ if (path == NULL) {
+ errno = EINVAL;
+ return (NULL);
+ }
+#if __DARWIN_UNIX03
+ if (*path == 0) {
+ errno = ENOENT;
+ return (NULL);
+ }
+#endif /* __DARWIN_UNIX03 */
+ /*
+ * Extension to the standard; if inresolved == NULL, allocate memory
+ * (first on the stack, then use strdup())
+ */
+ if (!inresolved) {
+ if ((resolved = alloca(PATH_MAX)) == NULL) return (NULL);
+ } else {
+ resolved = inresolved;
+ }
+ if (!rootdev_inited) {
+ rootdev_inited = 1;
+ if (stat("/", &sb) < 0) {
+ return (NULL);
+ }
+ rootdev = sb.st_dev;
+ }
serrno = errno;
symlinks = 0;
if (path[0] == '/') {
resolved[0] = '/';
resolved[1] = '\0';
- if (path[1] == '\0')
+ if (path[1] == '\0') {
return (resolved);
+ }
resolved_len = 1;
left_len = strlcpy(left, path + 1, sizeof(left));
} else {
- if (getcwd(resolved, PATH_MAX) == NULL) {
+#if !defined(VARIANT_DARWINEXTSN) && __DARWIN_UNIX03
+ /* 4447159: don't use GETPATH, so this will fail if */
+ /* if parent directories are not readable, as per POSIX */
+ if (__private_getcwd(resolved, PATH_MAX, 0) == NULL)
+#else /* VARIANT_DARWINEXTSN || !__DARWIN_UNIX03 */
+ if (__private_getcwd(resolved, PATH_MAX, 1) == NULL)
+#endif /* !VARIANT_DARWINEXTSN && __DARWIN_UNIX03 */
+ {
strlcpy(resolved, ".", PATH_MAX);
return (NULL);
}
@@ -80,6 +149,13 @@ realpath(const char *path, char resolved
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 +203,13 @@ realpath(const char *path, char resolved
}
/*
+ * 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.
@@ -136,25 +219,87 @@ realpath(const char *path, char resolved
errno = ENAMETOOLONG;
return (NULL);
}
- if (lstat(resolved, &sb) != 0) {
+ if (getattrlist(resolved, &_rp_alist, &attrs, sizeof(attrs), FSOPT_NOFOLLOW) == 0) {
+ useattrs = 1;
+ islink = (attrs.type == VLNK);
+ dev = attrs.dev;
+ inode = attrs.id.fid_objno;
+ } else if (errno == ENOTSUP || 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 !__DARWIN_UNIX03
if (errno == ENOENT && p == NULL) {
errno = serrno;
return (resolved);
}
+#endif /* !__DARWIN_UNIX03 */
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[sizeof(sfs.f_mntonname)];
+ 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);
}
slen = readlink(resolved, symlink, sizeof(symlink) - 1);
- if (slen < 0)
+ if (slen < 0) {
return (NULL);
+ }
symlink[slen] = '\0';
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 +329,30 @@ realpath(const char *path, char resolved
}
}
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.
+ */
}
/*
@@ -193,5 +361,6 @@ realpath(const char *path, char resolved
*/
if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
resolved[resolved_len - 1] = '\0';
+ if (!inresolved) resolved = strdup(resolved);
return (resolved);
}