--- 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); }