diff options
Diffstat (limited to 'lib/fts.c')
| -rw-r--r-- | lib/fts.c | 2085 |
1 files changed, 2085 insertions, 0 deletions
diff --git a/lib/fts.c b/lib/fts.c new file mode 100644 index 0000000..494a63a --- /dev/null +++ b/lib/fts.c @@ -0,0 +1,2085 @@ +/* Traverse a file hierarchy. + + Copyright (C) 2004-2022 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/*- + * Copyright (c) 1990, 1993, 1994 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <config.h> + +#if defined LIBC_SCCS && !defined GCC_LINT && !defined lint +static char sccsid[] = "@(#)fts.c 8.6 (Berkeley) 8/14/94"; +#endif + +#include "fts_.h" + +#if HAVE_SYS_PARAM_H || defined _LIBC +# include <sys/param.h> +#endif +#ifdef _LIBC +# include <include/sys/stat.h> +#else +# include <sys/stat.h> +#endif +#include <fcntl.h> +#include <errno.h> +#include <stdalign.h> +#include <stdbool.h> +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#if ! _LIBC +# include "attribute.h" +# include "fcntl--.h" +# include "flexmember.h" +# include "openat.h" +# include "opendirat.h" +# include "same-inode.h" +#endif + +#include <dirent.h> +#ifndef _D_EXACT_NAMLEN +# define _D_EXACT_NAMLEN(dirent) strlen ((dirent)->d_name) +#endif + +#if HAVE_STRUCT_DIRENT_D_TYPE +/* True if the type of the directory entry D is known. */ +# define DT_IS_KNOWN(d) ((d)->d_type != DT_UNKNOWN) +/* True if the type of the directory entry D must be T. */ +# define DT_MUST_BE(d, t) ((d)->d_type == (t)) +# define D_TYPE(d) ((d)->d_type) +#else +# define DT_IS_KNOWN(d) false +# define DT_MUST_BE(d, t) false +# define D_TYPE(d) DT_UNKNOWN + +# undef DT_UNKNOWN +# define DT_UNKNOWN 0 + +/* Any nonzero values will do here, so long as they're distinct. + Undef any existing macros out of the way. */ +# undef DT_BLK +# undef DT_CHR +# undef DT_DIR +# undef DT_FIFO +# undef DT_LNK +# undef DT_REG +# undef DT_SOCK +# define DT_BLK 1 +# define DT_CHR 2 +# define DT_DIR 3 +# define DT_FIFO 4 +# define DT_LNK 5 +# define DT_REG 6 +# define DT_SOCK 7 +#endif + +#ifndef S_IFLNK +# define S_IFLNK 0 +#endif +#ifndef S_IFSOCK +# define S_IFSOCK 0 +#endif + +enum +{ + NOT_AN_INODE_NUMBER = 0 +}; + +#ifdef D_INO_IN_DIRENT +# define D_INO(dp) (dp)->d_ino +#else +/* Some systems don't have inodes, so fake them to avoid lots of ifdefs. */ +# define D_INO(dp) NOT_AN_INODE_NUMBER +#endif + +/* If possible (see max_entries, below), read no more than this many directory + entries at a time. Without this limit (i.e., when using non-NULL + fts_compar), processing a directory with 4,000,000 entries requires ~1GiB + of memory, and handling 64M entries would require 16GiB of memory. */ +#ifndef FTS_MAX_READDIR_ENTRIES +# define FTS_MAX_READDIR_ENTRIES 100000 +#endif + +/* If there are more than this many entries in a directory, + and the conditions mentioned below are satisfied, then sort + the entries on inode number before any further processing. */ +#ifndef FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD +# define FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD 10000 +#endif + +enum +{ + _FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD = FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD +}; + +enum Fts_stat +{ + FTS_NO_STAT_REQUIRED = 1, + FTS_STAT_REQUIRED = 2 +}; + +#ifdef _LIBC +# undef close +# define close __close +# undef closedir +# define closedir __closedir +# undef fchdir +# define fchdir __fchdir +# undef open +# define open __open +# undef readdir +# define readdir __readdir +#else +# undef internal_function +# define internal_function /* empty */ +#endif + +#ifndef __set_errno +# define __set_errno(Val) errno = (Val) +#endif + +/* If this host provides the openat function, then we can avoid + attempting to open "." in some initialization code below. */ +#ifdef HAVE_OPENAT +# define HAVE_OPENAT_SUPPORT 1 +#else +# define HAVE_OPENAT_SUPPORT 0 +#endif + +#ifdef NDEBUG +# define fts_assert(expr) ((void) (0 && (expr))) +#else +# define fts_assert(expr) \ + do \ + { \ + if (!(expr)) \ + abort (); \ + } \ + while (false) +#endif + +#ifdef _LIBC +# if __GNUC__ >= 7 +# define FALLTHROUGH __attribute__ ((__fallthrough__)) +# else +# define FALLTHROUGH ((void) 0) +# endif +#endif + +static FTSENT *fts_alloc (FTS *, const char *, size_t) internal_function; +static FTSENT *fts_build (FTS *, int) internal_function; +static void fts_lfree (FTSENT *) internal_function; +static void fts_load (FTS *, FTSENT *) internal_function; +static size_t fts_maxarglen (char * const *) internal_function; +static void fts_padjust (FTS *, FTSENT *) internal_function; +static bool fts_palloc (FTS *, size_t) internal_function; +static FTSENT *fts_sort (FTS *, FTSENT *, size_t) internal_function; +static unsigned short int fts_stat (FTS *, FTSENT *, bool) internal_function; +static int fts_safe_changedir (FTS *, FTSENT *, int, const char *) + internal_function; + +#include "fts-cycle.c" + +#ifndef MAX +# define MAX(a,b) ((a) > (b) ? (a) : (b)) +#endif + +#ifndef SIZE_MAX +# define SIZE_MAX ((size_t) -1) +#endif + +#define ISDOT(a) (a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2]))) +#define STREQ(a, b) (strcmp (a, b) == 0) + +#define CLR(opt) (sp->fts_options &= ~(opt)) +#define ISSET(opt) (sp->fts_options & (opt)) +#define SET(opt) (sp->fts_options |= (opt)) + +/* FIXME: FTS_NOCHDIR is now misnamed. + Call it FTS_USE_FULL_RELATIVE_FILE_NAMES instead. */ +#define FCHDIR(sp, fd) \ + (!ISSET(FTS_NOCHDIR) && (ISSET(FTS_CWDFD) \ + ? (cwd_advance_fd ((sp), (fd), true), 0) \ + : fchdir (fd))) + + +/* fts_build flags */ +/* FIXME: make this an enum */ +#define BCHILD 1 /* fts_children */ +#define BNAMES 2 /* fts_children, names only */ +#define BREAD 3 /* fts_read */ + +#if FTS_DEBUG +# include <inttypes.h> +# include <stdint.h> +# include <stdio.h> +# include "getcwdat.h" +bool fts_debug = false; +# define Dprintf(x) do { if (fts_debug) printf x; } while (false) +#else +# define Dprintf(x) +# define fd_ring_check(x) +# define fd_ring_print(a, b, c) +#endif + +#define LEAVE_DIR(Fts, Ent, Tag) \ + do \ + { \ + Dprintf ((" %s-leaving: %s\n", Tag, (Ent)->fts_path)); \ + leave_dir (Fts, Ent); \ + fd_ring_check (Fts); \ + } \ + while (false) + +static void +fd_ring_clear (I_ring *fd_ring) +{ + while ( ! i_ring_empty (fd_ring)) + { + int fd = i_ring_pop (fd_ring); + if (0 <= fd) + close (fd); + } +} + +/* Overload the fts_statp->st_size member (otherwise unused, when + fts_info is FTS_NSOK) to indicate whether fts_read should stat + this entry or not. */ +static void +fts_set_stat_required (FTSENT *p, bool required) +{ + fts_assert (p->fts_info == FTS_NSOK); + p->fts_statp->st_size = (required + ? FTS_STAT_REQUIRED + : FTS_NO_STAT_REQUIRED); +} + +/* Virtual fchdir. Advance SP's working directory file descriptor, + SP->fts_cwd_fd, to FD, and push the previous value onto the fd_ring. + CHDIR_DOWN_ONE is true if FD corresponds to an entry in the directory + open on sp->fts_cwd_fd; i.e., to move the working directory one level + down. */ +static void +internal_function +cwd_advance_fd (FTS *sp, int fd, bool chdir_down_one) +{ + int old = sp->fts_cwd_fd; + fts_assert (old != fd || old == AT_FDCWD); + + if (chdir_down_one) + { + /* Push "old" onto the ring. + If the displaced file descriptor is non-negative, close it. */ + int prev_fd_in_slot = i_ring_push (&sp->fts_fd_ring, old); + fd_ring_print (sp, stderr, "post-push"); + if (0 <= prev_fd_in_slot) + close (prev_fd_in_slot); /* ignore any close failure */ + } + else if ( ! ISSET (FTS_NOCHDIR)) + { + if (0 <= old) + close (old); /* ignore any close failure */ + } + + sp->fts_cwd_fd = fd; +} + +/* Restore the initial, pre-traversal, "working directory". + In FTS_CWDFD mode, we merely call cwd_advance_fd, otherwise, + we may actually change the working directory. + Return 0 upon success. Upon failure, set errno and return nonzero. */ +static int +restore_initial_cwd (FTS *sp) +{ + int fail = FCHDIR (sp, ISSET (FTS_CWDFD) ? AT_FDCWD : sp->fts_rfd); + fd_ring_clear (&(sp->fts_fd_ring)); + return fail; +} + +/* Open the directory DIR if possible, and return a file + descriptor. Return -1 and set errno on failure. It doesn't matter + whether the file descriptor has read or write access. */ + +static int +internal_function +diropen (FTS const *sp, char const *dir) +{ + int open_flags = (O_SEARCH | O_CLOEXEC | O_DIRECTORY | O_NOCTTY | O_NONBLOCK + | (ISSET (FTS_PHYSICAL) ? O_NOFOLLOW : 0)); + + int fd = (ISSET (FTS_CWDFD) + ? openat (sp->fts_cwd_fd, dir, open_flags) + : open (dir, open_flags)); + return fd; +} + +FTS * +fts_open (char * const *argv, + register int options, + int (*compar) (FTSENT const **, FTSENT const **)) +{ + register FTS *sp; + register FTSENT *p, *root; + register size_t nitems; + FTSENT *parent = NULL; + FTSENT *tmp = NULL; /* pacify gcc */ + bool defer_stat; + + /* Options check. */ + if (options & ~FTS_OPTIONMASK) { + __set_errno (EINVAL); + return (NULL); + } + if ((options & FTS_NOCHDIR) && (options & FTS_CWDFD)) { + __set_errno (EINVAL); + return (NULL); + } + if ( ! (options & (FTS_LOGICAL | FTS_PHYSICAL))) { + __set_errno (EINVAL); + return (NULL); + } + + /* Allocate/initialize the stream */ + sp = calloc (1, sizeof *sp); + if (sp == NULL) + return (NULL); + sp->fts_compar = compar; + sp->fts_options = options; + + /* Logical walks turn on NOCHDIR; symbolic links are too hard. */ + if (ISSET(FTS_LOGICAL)) { + SET(FTS_NOCHDIR); + CLR(FTS_CWDFD); + } + + /* Initialize fts_cwd_fd. */ + sp->fts_cwd_fd = AT_FDCWD; + if ( ISSET(FTS_CWDFD) && ! HAVE_OPENAT_SUPPORT) + { + /* While it isn't technically necessary to open "." this + early, doing it here saves us the trouble of ensuring + later (where it'd be messier) that "." can in fact + be opened. If not, revert to FTS_NOCHDIR mode. */ + int fd = open (".", O_SEARCH | O_CLOEXEC); + if (fd < 0) + { + /* Even if "." is unreadable, don't revert to FTS_NOCHDIR mode + on systems like Linux+PROC_FS, where our openat emulation + is good enough. Note: on a system that emulates + openat via /proc, this technique can still fail, but + only in extreme conditions, e.g., when the working + directory cannot be saved (i.e. save_cwd fails) -- + and that happens on Linux only when "." is unreadable + and the CWD would be longer than PATH_MAX. + FIXME: once Linux kernel openat support is well established, + replace the above open call and this entire if/else block + with the body of the if-block below. */ + if ( openat_needs_fchdir ()) + { + SET(FTS_NOCHDIR); + CLR(FTS_CWDFD); + } + } + else + { + close (fd); + } + } + + /* + * Start out with 1K of file name space, and enough, in any case, + * to hold the user's file names. + */ +#ifndef MAXPATHLEN +# define MAXPATHLEN 1024 +#endif + { + size_t maxarglen = fts_maxarglen(argv); + if (! fts_palloc(sp, MAX(maxarglen, MAXPATHLEN))) + goto mem1; + } + + /* Allocate/initialize root's parent. */ + if (*argv != NULL) { + if ((parent = fts_alloc(sp, "", 0)) == NULL) + goto mem2; + parent->fts_level = FTS_ROOTPARENTLEVEL; + } + + /* The classic fts implementation would call fts_stat with + a new entry for each iteration of the loop below. + If the comparison function is not specified or if the + FTS_DEFER_STAT option is in effect, don't stat any entry + in this loop. This is an attempt to minimize the interval + between the initial stat/lstat/fstatat and the point at which + a directory argument is first opened. This matters for any + directory command line argument that resides on a file system + without genuine i-nodes. If you specify FTS_DEFER_STAT along + with a comparison function, that function must not access any + data via the fts_statp pointer. */ + defer_stat = (compar == NULL || ISSET(FTS_DEFER_STAT)); + + /* Allocate/initialize root(s). */ + for (root = NULL, nitems = 0; *argv != NULL; ++argv, ++nitems) { + /* *Do* allow zero-length file names. */ + size_t len = strlen(*argv); + + if ( ! (options & FTS_VERBATIM)) + { + /* If there are two or more trailing slashes, trim all but one, + but don't change "//" to "/", and do map "///" to "/". */ + char const *v = *argv; + if (2 < len && v[len - 1] == '/') + while (1 < len && v[len - 2] == '/') + --len; + } + + if ((p = fts_alloc(sp, *argv, len)) == NULL) + goto mem3; + p->fts_level = FTS_ROOTLEVEL; + p->fts_parent = parent; + p->fts_accpath = p->fts_name; + /* Even when defer_stat is true, be sure to stat the first + command line argument, since fts_read (at least with + FTS_XDEV) requires that. */ + if (defer_stat && root != NULL) { + p->fts_info = FTS_NSOK; + fts_set_stat_required(p, true); + } else { + p->fts_info = fts_stat(sp, p, false); + } + + /* + * If comparison routine supplied, traverse in sorted + * order; otherwise traverse in the order specified. + */ + if (compar) { + p->fts_link = root; + root = p; + } else { + p->fts_link = NULL; + if (root == NULL) + tmp = root = p; + else { + tmp->fts_link = p; + tmp = p; + } + } + } + if (compar && nitems > 1) + root = fts_sort(sp, root, nitems); + + /* + * Allocate a dummy pointer and make fts_read think that we've just + * finished the node before the root(s); set p->fts_info to FTS_INIT + * so that everything about the "current" node is ignored. + */ + if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL) + goto mem3; + sp->fts_cur->fts_link = root; + sp->fts_cur->fts_info = FTS_INIT; + sp->fts_cur->fts_level = 1; + if (! setup_dir (sp)) + goto mem3; + + /* + * If using chdir(2), grab a file descriptor pointing to dot to ensure + * that we can get back here; this could be avoided for some file names, + * but almost certainly not worth the effort. Slashes, symbolic links, + * and ".." are all fairly nasty problems. Note, if we can't get the + * descriptor we run anyway, just more slowly. + */ + if (!ISSET(FTS_NOCHDIR) && !ISSET(FTS_CWDFD) + && (sp->fts_rfd = diropen (sp, ".")) < 0) + SET(FTS_NOCHDIR); + + i_ring_init (&sp->fts_fd_ring, -1); + return (sp); + +mem3: fts_lfree(root); + free(parent); +mem2: free(sp->fts_path); +mem1: free(sp); + return (NULL); +} + +static void +internal_function +fts_load (FTS *sp, register FTSENT *p) +{ + register size_t len; + register char *cp; + + /* + * Load the stream structure for the next traversal. Since we don't + * actually enter the directory until after the preorder visit, set + * the fts_accpath field specially so the chdir gets done to the right + * place and the user can access the first node. From fts_open it's + * known that the file name will fit. + */ + len = p->fts_pathlen = p->fts_namelen; + memmove(sp->fts_path, p->fts_name, len + 1); + if ((cp = strrchr(p->fts_name, '/')) && (cp != p->fts_name || cp[1])) { + len = strlen(++cp); + memmove(p->fts_name, cp, len + 1); + p->fts_namelen = len; + } + p->fts_accpath = p->fts_path = sp->fts_path; +} + +int +fts_close (FTS *sp) +{ + register FTSENT *freep, *p; + int saved_errno = 0; + + /* + * This still works if we haven't read anything -- the dummy structure + * points to the root list, so we step through to the end of the root + * list which has a valid parent pointer. + */ + if (sp->fts_cur) { + for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) { + freep = p; + p = p->fts_link != NULL ? p->fts_link : p->fts_parent; + free(freep); + } + free(p); + } + + /* Free up child linked list, sort array, file name buffer. */ + if (sp->fts_child) + fts_lfree(sp->fts_child); + free(sp->fts_array); + free(sp->fts_path); + + if (ISSET(FTS_CWDFD)) + { + if (0 <= sp->fts_cwd_fd) + if (close (sp->fts_cwd_fd)) + saved_errno = errno; + } + else if (!ISSET(FTS_NOCHDIR)) + { + /* Return to original directory, save errno if necessary. */ + if (fchdir(sp->fts_rfd)) + saved_errno = errno; + + /* If close fails, record errno only if saved_errno is zero, + so that we report the probably-more-meaningful fchdir errno. */ + if (close (sp->fts_rfd)) + if (saved_errno == 0) + saved_errno = errno; + } + + fd_ring_clear (&sp->fts_fd_ring); + + if (sp->fts_leaf_optimization_works_ht) + hash_free (sp->fts_leaf_optimization_works_ht); + + free_dir (sp); + + /* Free up the stream pointer. */ + free(sp); + + /* Set errno and return. */ + if (saved_errno) { + __set_errno (saved_errno); + return (-1); + } + + return (0); +} + +/* Minimum link count of a traditional Unix directory. When leaf + optimization is OK and a directory's st_nlink == MIN_DIR_NLINK, + then the directory has no subdirectories. */ +enum { MIN_DIR_NLINK = 2 }; + +/* Whether leaf optimization is OK for a directory. */ +enum leaf_optimization + { + /* st_nlink is not reliable for this directory's subdirectories. */ + NO_LEAF_OPTIMIZATION, + + /* st_nlink == 2 means the directory lacks subdirectories. */ + OK_LEAF_OPTIMIZATION + }; + +#if (defined __linux__ || defined __ANDROID__) \ + && HAVE_SYS_VFS_H && HAVE_FSTATFS && HAVE_STRUCT_STATFS_F_TYPE + +# include <sys/vfs.h> + +/* Linux-specific constants from coreutils' src/fs.h */ +# define S_MAGIC_AFS 0x5346414F +# define S_MAGIC_CIFS 0xFF534D42 +# define S_MAGIC_NFS 0x6969 +# define S_MAGIC_PROC 0x9FA0 +# define S_MAGIC_TMPFS 0x1021994 + +# ifdef HAVE___FSWORD_T +typedef __fsword_t fsword; +# else +typedef long int fsword; +# endif + +/* Map a stat.st_dev number to a file system type number f_ftype. */ +struct dev_type +{ + dev_t st_dev; + fsword f_type; +}; + +/* Use a tiny initial size. If a traversal encounters more than + a few devices, the cost of growing/rehashing this table will be + rendered negligible by the number of inodes processed. */ +enum { DEV_TYPE_HT_INITIAL_SIZE = 13 }; + +static size_t +dev_type_hash (void const *x, size_t table_size) +{ + struct dev_type const *ax = x; + uintmax_t dev = ax->st_dev; + return dev % table_size; +} + +static bool +dev_type_compare (void const *x, void const *y) +{ + struct dev_type const *ax = x; + struct dev_type const *ay = y; + return ax->st_dev == ay->st_dev; +} + +/* Return the file system type of P with file descriptor FD, or 0 if not known. + If FD is negative, P's file descriptor is unavailable. + Try to cache known values. */ + +static fsword +filesystem_type (FTSENT const *p, int fd) +{ + FTS *sp = p->fts_fts; + Hash_table *h = sp->fts_leaf_optimization_works_ht; + struct dev_type *ent; + struct statfs fs_buf; + + /* If we're not in CWDFD mode, don't bother with this optimization, + since the caller is not serious about performance. */ + if (!ISSET (FTS_CWDFD)) + return 0; + + if (! h) + h = sp->fts_leaf_optimization_works_ht + = hash_initialize (DEV_TYPE_HT_INITIAL_SIZE, NULL, dev_type_hash, + dev_type_compare, free); + if (h) + { + struct dev_type tmp; + tmp.st_dev = p->fts_statp->st_dev; + ent = hash_lookup (h, &tmp); + if (ent) + return ent->f_type; + } + + /* Look-up failed. Query directly and cache the result. */ + if (fd < 0 || fstatfs (fd, &fs_buf) != 0) + return 0; + + if (h) + { + struct dev_type *t2 = malloc (sizeof *t2); + if (t2) + { + t2->st_dev = p->fts_statp->st_dev; + t2->f_type = fs_buf.f_type; + + ent = hash_insert (h, t2); + if (ent) + fts_assert (ent == t2); + else + free (t2); + } + } + + return fs_buf.f_type; +} + +/* Return true if sorting dirents on inode numbers is known to improve + traversal performance for the directory P with descriptor DIR_FD. + Return false otherwise. When in doubt, return true. + DIR_FD is negative if unavailable. */ +static bool +dirent_inode_sort_may_be_useful (FTSENT const *p, int dir_fd) +{ + /* Skip the sort only if we can determine efficiently + that skipping it is the right thing to do. + The cost of performing an unnecessary sort is negligible, + while the cost of *not* performing it can be O(N^2) with + a very large constant. */ + + switch (filesystem_type (p, dir_fd)) + { + case S_MAGIC_CIFS: + case S_MAGIC_NFS: + case S_MAGIC_TMPFS: + /* On a file system of any of these types, sorting + is unnecessary, and hence wasteful. */ + return false; + + default: + return true; + } +} + +/* Given an FTS entry P for a directory with descriptor DIR_FD, + return whether it is valid to apply leaf optimization. + The optimization is valid if a directory's st_nlink value equal + to MIN_DIR_NLINK means the directory has no subdirectories. + DIR_FD is negative if unavailable. */ +static enum leaf_optimization +leaf_optimization (FTSENT const *p, int dir_fd) +{ + switch (filesystem_type (p, dir_fd)) + { + case 0: + /* Leaf optimization is unsafe if the file system type is unknown. */ + FALLTHROUGH; + case S_MAGIC_AFS: + /* Although AFS mount points are not counted in st_nlink, they + act like directories. See <https://bugs.debian.org/143111>. */ + FALLTHROUGH; + case S_MAGIC_CIFS: + /* Leaf optimization causes 'find' to abort. See + <https://lists.gnu.org/r/bug-gnulib/2018-04/msg00015.html>. */ + FALLTHROUGH; + case S_MAGIC_NFS: + /* NFS provides usable dirent.d_type but not necessarily for all entries + of large directories, so as per <https://bugzilla.redhat.com/1252549> + NFS should return true. However st_nlink values are not accurate on + all implementations as per <https://bugzilla.redhat.com/1299169>. */ + FALLTHROUGH; + case S_MAGIC_PROC: + /* Per <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=143111> /proc + may have bogus stat.st_nlink values. */ + return NO_LEAF_OPTIMIZATION; + + default: + return OK_LEAF_OPTIMIZATION; + } +} + +#else +static bool +dirent_inode_sort_may_be_useful (_GL_UNUSED FTSENT const *p, + _GL_UNUSED int dir_fd) +{ + return true; +} +static enum leaf_optimization +leaf_optimization (_GL_UNUSED FTSENT const *p, _GL_UNUSED int dir_fd) +{ + return NO_LEAF_OPTIMIZATION; +} +#endif + +/* + * Special case of "/" at the end of the file name so that slashes aren't + * appended which would cause file names to be written as "....//foo". + */ +#define NAPPEND(p) \ + (p->fts_path[p->fts_pathlen - 1] == '/' \ + ? p->fts_pathlen - 1 : p->fts_pathlen) + +FTSENT * +fts_read (register FTS *sp) +{ + register FTSENT *p, *tmp; + register unsigned short int instr; + register char *t; + + /* If finished or unrecoverable error, return NULL. */ + if (sp->fts_cur == NULL || ISSET(FTS_STOP)) + return (NULL); + + /* Set current node pointer. */ + p = sp->fts_cur; + + /* Save and zero out user instructions. */ + instr = p->fts_instr; + p->fts_instr = FTS_NOINSTR; + + /* Any type of file may be re-visited; re-stat and re-turn. */ + if (instr == FTS_AGAIN) { + p->fts_info = fts_stat(sp, p, false); + return (p); + } + Dprintf (("fts_read: p=%s\n", + p->fts_info == FTS_INIT ? "" : p->fts_path)); + + /* + * Following a symlink -- SLNONE test allows application to see + * SLNONE and recover. If indirecting through a symlink, have + * keep a pointer to current location. If unable to get that + * pointer, follow fails. + */ + if (instr == FTS_FOLLOW && + (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) { + p->fts_info = fts_stat(sp, p, true); + if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) { + if ((p->fts_symfd = diropen (sp, ".")) < 0) { + p->fts_errno = errno; + p->fts_info = FTS_ERR; + } else + p->fts_flags |= FTS_SYMFOLLOW; + } + goto check_for_dir; + } + + /* Directory in pre-order. */ + if (p->fts_info == FTS_D) { + /* If skipped or crossed mount point, do post-order visit. */ + if (instr == FTS_SKIP || + (ISSET(FTS_XDEV) && p->fts_statp->st_dev != sp->fts_dev)) { + if (p->fts_flags & FTS_SYMFOLLOW) + (void)close(p->fts_symfd); + if (sp->fts_child) { + fts_lfree(sp->fts_child); + sp->fts_child = NULL; + } + p->fts_info = FTS_DP; + LEAVE_DIR (sp, p, "1"); + return (p); + } + + /* Rebuild if only read the names and now traversing. */ + if (sp->fts_child != NULL && ISSET(FTS_NAMEONLY)) { + CLR(FTS_NAMEONLY); + fts_lfree(sp->fts_child); + sp->fts_child = NULL; + } + + /* + * Cd to the subdirectory. + * + * If have already read and now fail to chdir, whack the list + * to make the names come out right, and set the parent errno + * so the application will eventually get an error condition. + * Set the FTS_DONTCHDIR flag so that when we logically change + * directories back to the parent we don't do a chdir. + * + * If haven't read do so. If the read fails, fts_build sets + * FTS_STOP or the fts_info field of the node. + */ + if (sp->fts_child != NULL) { + if (fts_safe_changedir(sp, p, -1, p->fts_accpath)) { + p->fts_errno = errno; + p->fts_flags |= FTS_DONTCHDIR; + for (p = sp->fts_child; p != NULL; + p = p->fts_link) + p->fts_accpath = + p->fts_parent->fts_accpath; + } + } else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) { + if (ISSET(FTS_STOP)) + return (NULL); + /* If fts_build's call to fts_safe_changedir failed + because it was not able to fchdir into a + subdirectory, tell the caller. */ + if (p->fts_errno && p->fts_info != FTS_DNR) + p->fts_info = FTS_ERR; + LEAVE_DIR (sp, p, "2"); + return (p); + } + p = sp->fts_child; + sp->fts_child = NULL; + goto name; + } + + /* Move to the next node on this level. */ +next: tmp = p; + + /* If we have so many directory entries that we're reading them + in batches, and we've reached the end of the current batch, + read in a new batch. */ + if (p->fts_link == NULL && p->fts_parent->fts_dirp) + { + p = tmp->fts_parent; + sp->fts_cur = p; + sp->fts_path[p->fts_pathlen] = '\0'; + + if ((p = fts_build (sp, BREAD)) == NULL) + { + if (ISSET(FTS_STOP)) + return NULL; + goto cd_dot_dot; + } + + free(tmp); + goto name; + } + + if ((p = p->fts_link) != NULL) { + sp->fts_cur = p; + free(tmp); + + /* + * If reached the top, return to the original directory (or + * the root of the tree), and load the file names for the next + * root. + */ + if (p->fts_level == FTS_ROOTLEVEL) { + if (restore_initial_cwd(sp)) { + SET(FTS_STOP); + return (NULL); + } + free_dir(sp); + fts_load(sp, p); + setup_dir(sp); + goto check_for_dir; + } + + /* + * User may have called fts_set on the node. If skipped, + * ignore. If followed, get a file descriptor so we can + * get back if necessary. + */ + if (p->fts_instr == FTS_SKIP) + goto next; + if (p->fts_instr == FTS_FOLLOW) { + p->fts_info = fts_stat(sp, p, true); + if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) { + if ((p->fts_symfd = diropen (sp, ".")) < 0) { + p->fts_errno = errno; + p->fts_info = FTS_ERR; + } else + p->fts_flags |= FTS_SYMFOLLOW; + } + p->fts_instr = FTS_NOINSTR; + } + +name: t = sp->fts_path + NAPPEND(p->fts_parent); + *t++ = '/'; + memmove(t, p->fts_name, p->fts_namelen + 1); +check_for_dir: + sp->fts_cur = p; + if (p->fts_info == FTS_NSOK) + { + if (p->fts_statp->st_size == FTS_STAT_REQUIRED) + p->fts_info = fts_stat(sp, p, false); + else + fts_assert (p->fts_statp->st_size == FTS_NO_STAT_REQUIRED); + } + + if (p->fts_info == FTS_D) + { + /* Now that P->fts_statp is guaranteed to be valid, + if this is a command-line directory, record its + device number, to be used for FTS_XDEV. */ + if (p->fts_level == FTS_ROOTLEVEL) + sp->fts_dev = p->fts_statp->st_dev; + Dprintf ((" entering: %s\n", p->fts_path)); + if (! enter_dir (sp, p)) + { + __set_errno (ENOMEM); + return NULL; + } + } + return p; + } +cd_dot_dot: + + /* Move up to the parent node. */ + p = tmp->fts_parent; + sp->fts_cur = p; + free(tmp); + + if (p->fts_level == FTS_ROOTPARENTLEVEL) { + /* + * Done; free everything up and set errno to 0 so the user + * can distinguish between error and EOF. + */ + free(p); + __set_errno (0); + return (sp->fts_cur = NULL); + } + + fts_assert (p->fts_info != FTS_NSOK); + + /* NUL terminate the file name. */ + sp->fts_path[p->fts_pathlen] = '\0'; + + /* + * Return to the parent directory. If at a root node, restore + * the initial working directory. If we came through a symlink, + * go back through the file descriptor. Otherwise, move up + * one level, via "..". + */ + if (p->fts_level == FTS_ROOTLEVEL) { + if (restore_initial_cwd(sp)) { + p->fts_errno = errno; + SET(FTS_STOP); + } + } else if (p->fts_flags & FTS_SYMFOLLOW) { + if (FCHDIR(sp, p->fts_symfd)) { + p->fts_errno = errno; + SET(FTS_STOP); + } + (void)close(p->fts_symfd); + } else if (!(p->fts_flags & FTS_DONTCHDIR) && + fts_safe_changedir(sp, p->fts_parent, -1, "..")) { + p->fts_errno = errno; + SET(FTS_STOP); + } + + /* If the directory causes a cycle, preserve the FTS_DC flag and keep + the corresponding dev/ino pair in the hash table. It is going to be + removed when leaving the original directory. */ + if (p->fts_info != FTS_DC) { + p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP; + if (p->fts_errno == 0) + LEAVE_DIR (sp, p, "3"); + } + return ISSET(FTS_STOP) ? NULL : p; +} + +/* + * Fts_set takes the stream as an argument although it's not used in this + * implementation; it would be necessary if anyone wanted to add global + * semantics to fts using fts_set. An error return is allowed for similar + * reasons. + */ +/* ARGSUSED */ +int +fts_set(_GL_UNUSED FTS *sp, FTSENT *p, int instr) +{ + if (instr != 0 && instr != FTS_AGAIN && instr != FTS_FOLLOW && + instr != FTS_NOINSTR && instr != FTS_SKIP) { + __set_errno (EINVAL); + return (1); + } + p->fts_instr = instr; + return (0); +} + +FTSENT * +fts_children (register FTS *sp, int instr) +{ + register FTSENT *p; + int fd; + + if (instr != 0 && instr != FTS_NAMEONLY) { + __set_errno (EINVAL); + return (NULL); + } + + /* Set current node pointer. */ + p = sp->fts_cur; + + /* + * Errno set to 0 so user can distinguish empty directory from + * an error. + */ + __set_errno (0); + + /* Fatal errors stop here. */ + if (ISSET(FTS_STOP)) + return (NULL); + + /* Return logical hierarchy of user's arguments. */ + if (p->fts_info == FTS_INIT) + return (p->fts_link); + + /* + * If not a directory being visited in pre-order, stop here. Could + * allow FTS_DNR, assuming the user has fixed the problem, but the + * same effect is available with FTS_AGAIN. + */ + if (p->fts_info != FTS_D /* && p->fts_info != FTS_DNR */) + return (NULL); + + /* Free up any previous child list. */ + if (sp->fts_child != NULL) + fts_lfree(sp->fts_child); + + if (instr == FTS_NAMEONLY) { + SET(FTS_NAMEONLY); + instr = BNAMES; + } else + instr = BCHILD; + + /* + * If using chdir on a relative file name and called BEFORE fts_read + * does its chdir to the root of a traversal, we can lose -- we need to + * chdir into the subdirectory, and we don't know where the current + * directory is, so we can't get back so that the upcoming chdir by + * fts_read will work. + */ + if (p->fts_level != FTS_ROOTLEVEL || p->fts_accpath[0] == '/' || + ISSET(FTS_NOCHDIR)) + return (sp->fts_child = fts_build(sp, instr)); + + if ((fd = diropen (sp, ".")) < 0) + return (sp->fts_child = NULL); + sp->fts_child = fts_build(sp, instr); + if (ISSET(FTS_CWDFD)) + { + cwd_advance_fd (sp, fd, true); + } + else + { + if (fchdir(fd)) + { + int saved_errno = errno; + close (fd); + __set_errno (saved_errno); + return NULL; + } + close (fd); + } + return (sp->fts_child); +} + +/* A comparison function to sort on increasing inode number. + For some file system types, sorting either way makes a huge + performance difference for a directory with very many entries, + but sorting on increasing values is slightly better than sorting + on decreasing values. The difference is in the 5% range. */ +static int +fts_compare_ino (struct _ftsent const **a, struct _ftsent const **b) +{ + return _GL_CMP (a[0]->fts_statp->st_ino, b[0]->fts_statp->st_ino); +} + +/* Map the dirent.d_type value, DTYPE, to the corresponding stat.st_mode + S_IF* bit and set ST.st_mode, thus clearing all other bits in that field. */ +static void +set_stat_type (struct stat *st, unsigned int dtype) +{ + mode_t type; + switch (dtype) + { + case DT_BLK: + type = S_IFBLK; + break; + case DT_CHR: + type = S_IFCHR; + break; + case DT_DIR: + type = S_IFDIR; + break; + case DT_FIFO: + type = S_IFIFO; + break; + case DT_LNK: + type = S_IFLNK; + break; + case DT_REG: + type = S_IFREG; + break; + case DT_SOCK: + type = S_IFSOCK; + break; + default: + type = 0; + } + st->st_mode = type; +} + +#define closedir_and_clear(dirp) \ + do \ + { \ + closedir (dirp); \ + dirp = NULL; \ + } \ + while (0) + +#define fts_opendir(file, Pdir_fd) \ + opendirat((! ISSET(FTS_NOCHDIR) && ISSET(FTS_CWDFD) \ + ? sp->fts_cwd_fd : AT_FDCWD), \ + file, \ + (((ISSET(FTS_PHYSICAL) \ + && ! (ISSET(FTS_COMFOLLOW) \ + && cur->fts_level == FTS_ROOTLEVEL)) \ + ? O_NOFOLLOW : 0)), \ + Pdir_fd) + +/* + * This is the tricky part -- do not casually change *anything* in here. The + * idea is to build the linked list of entries that are used by fts_children + * and fts_read. There are lots of special cases. + * + * The real slowdown in walking the tree is the stat calls. If FTS_NOSTAT is + * set and it's a physical walk (so that symbolic links can't be directories), + * we can do things quickly. First, if it's a 4.4BSD file system, the type + * of the file is in the directory entry. Otherwise, we assume that the number + * of subdirectories in a node is equal to the number of links to the parent. + * The former skips all stat calls. The latter skips stat calls in any leaf + * directories and for any files after the subdirectories in the directory have + * been found, cutting the stat calls by about 2/3. + */ +static FTSENT * +internal_function +fts_build (register FTS *sp, int type) +{ + register FTSENT *p, *head; + register size_t nitems; + FTSENT *tail; + void *oldaddr; + int saved_errno; + bool descend; + bool doadjust; + ptrdiff_t level; + size_t len, maxlen, new_len; + char *cp; + int dir_fd; + FTSENT *cur = sp->fts_cur; + bool continue_readdir = !!cur->fts_dirp; + bool sort_by_inode = false; + size_t max_entries; + + /* When cur->fts_dirp is non-NULL, that means we should + continue calling readdir on that existing DIR* pointer + rather than opening a new one. */ + if (continue_readdir) + { + DIR *dp = cur->fts_dirp; + dir_fd = dirfd (dp); + if (dir_fd < 0) + { + closedir_and_clear (cur->fts_dirp); + if (type == BREAD) + { + cur->fts_info = FTS_DNR; + cur->fts_errno = errno; + } + return NULL; + } + } + else + { + /* Open the directory for reading. If this fails, we're done. + If being called from fts_read, set the fts_info field. */ + if ((cur->fts_dirp = fts_opendir(cur->fts_accpath, &dir_fd)) == NULL) + { + if (type == BREAD) + { + cur->fts_info = FTS_DNR; + cur->fts_errno = errno; + } + return NULL; + } + /* Rather than calling fts_stat for each and every entry encountered + in the readdir loop (below), stat each directory only right after + opening it. */ + if (cur->fts_info == FTS_NSOK) + cur->fts_info = fts_stat(sp, cur, false); + else if (sp->fts_options & FTS_TIGHT_CYCLE_CHECK) + { + /* Now read the stat info again after opening a directory to + reveal eventual changes caused by a submount triggered by + the traversal. But do it only for utilities which use + FTS_TIGHT_CYCLE_CHECK. Therefore, only find and du + benefit/suffer from this feature for now. */ + LEAVE_DIR (sp, cur, "4"); + fts_stat (sp, cur, false); + if (! enter_dir (sp, cur)) + { + __set_errno (ENOMEM); + return NULL; + } + } + } + + /* Maximum number of readdir entries to read at one time. This + limitation is to avoid reading millions of entries into memory + at once. When an fts_compar function is specified, we have no + choice: we must read all entries into memory before calling that + function. But when no such function is specified, we can read + entries in batches that are large enough to help us with inode- + sorting, yet not so large that we risk exhausting memory. */ + max_entries = sp->fts_compar ? SIZE_MAX : FTS_MAX_READDIR_ENTRIES; + + /* + * If we're going to need to stat anything or we want to descend + * and stay in the directory, chdir. If this fails we keep going, + * but set a flag so we don't chdir after the post-order visit. + * We won't be able to stat anything, but we can still return the + * names themselves. Note, that since fts_read won't be able to + * chdir into the directory, it will have to return different file + * names than before, i.e. "a/b" instead of "b". Since the node + * has already been visited in pre-order, have to wait until the + * post-order visit to return the error. There is a special case + * here, if there was nothing to stat then it's not an error to + * not be able to stat. This is all fairly nasty. If a program + * needed sorted entries or stat information, they had better be + * checking FTS_NS on the returned nodes. + */ + if (continue_readdir) + { + /* When resuming a short readdir run, we already have + the required dirp and dir_fd. */ + descend = true; + } + else + { + /* Try to descend unless it is a names-only fts_children, + or the directory is known to lack subdirectories. */ + descend = (type != BNAMES + && ! (ISSET (FTS_NOSTAT) && ISSET (FTS_PHYSICAL) + && ! ISSET (FTS_SEEDOT) + && cur->fts_statp->st_nlink == MIN_DIR_NLINK + && (leaf_optimization (cur, dir_fd) + != NO_LEAF_OPTIMIZATION))); + if (descend || type == BREAD) + { + if (ISSET(FTS_CWDFD)) + dir_fd = fcntl (dir_fd, F_DUPFD_CLOEXEC, STDERR_FILENO + 1); + if (dir_fd < 0 || fts_safe_changedir(sp, cur, dir_fd, NULL)) { + if (descend && type == BREAD) + cur->fts_errno = errno; + cur->fts_flags |= FTS_DONTCHDIR; + descend = false; + closedir_and_clear(cur->fts_dirp); + if (ISSET(FTS_CWDFD) && 0 <= dir_fd) + close (dir_fd); + cur->fts_dirp = NULL; + } else + descend = true; + } + } + + /* + * Figure out the max file name length that can be stored in the + * current buffer -- the inner loop allocates more space as necessary. + * We really wouldn't have to do the maxlen calculations here, we + * could do them in fts_read before returning the name, but it's a + * lot easier here since the length is part of the dirent structure. + * + * If not changing directories set a pointer so that can just append + * each new component into the file name. + */ + len = NAPPEND(cur); + if (ISSET(FTS_NOCHDIR)) { + cp = sp->fts_path + len; + *cp++ = '/'; + } else { + /* GCC, you're too verbose. */ + cp = NULL; + } + len++; + maxlen = sp->fts_pathlen - len; + + level = cur->fts_level + 1; + + /* Read the directory, attaching each entry to the "link" pointer. */ + doadjust = false; + head = NULL; + tail = NULL; + nitems = 0; + while (cur->fts_dirp) { + size_t d_namelen; + __set_errno (0); + struct dirent *dp = readdir(cur->fts_dirp); + if (dp == NULL) { + if (errno) { + cur->fts_errno = errno; + /* If we've not read any items yet, treat + the error as if we can't access the dir. */ + cur->fts_info = (continue_readdir || nitems) + ? FTS_ERR : FTS_DNR; + } + break; + } + if (!ISSET(FTS_SEEDOT) && ISDOT(dp->d_name)) + continue; + + d_namelen = _D_EXACT_NAMLEN (dp); + p = fts_alloc (sp, dp->d_name, d_namelen); + if (!p) + goto mem1; + if (d_namelen >= maxlen) { + /* include space for NUL */ + oldaddr = sp->fts_path; + if (! fts_palloc(sp, d_namelen + len + 1)) { + /* + * No more memory. Save + * errno, free up the current structure and the + * structures already allocated. + */ +mem1: saved_errno = errno; + free(p); + fts_lfree(head); + closedir_and_clear(cur->fts_dirp); + cur->fts_info = FTS_ERR; + SET(FTS_STOP); + __set_errno (saved_errno); + return (NULL); + } + /* Did realloc() change the pointer? */ + if (oldaddr != sp->fts_path) { + doadjust = true; + if (ISSET(FTS_NOCHDIR)) + cp = sp->fts_path + len; + } + maxlen = sp->fts_pathlen - len; + } + + new_len = len + d_namelen; + if (new_len < len) { + /* + * In the unlikely event that we would end up + * with a file name longer than SIZE_MAX, free up + * the current structure and the structures already + * allocated, then error out with ENAMETOOLONG. + */ + free(p); + fts_lfree(head); + closedir_and_clear(cur->fts_dirp); + cur->fts_info = FTS_ERR; + SET(FTS_STOP); + __set_errno (ENAMETOOLONG); + return (NULL); + } + p->fts_level = level; + p->fts_parent = sp->fts_cur; + p->fts_pathlen = new_len; + + /* Store dirent.d_ino, in case we need to sort + entries before processing them. */ + p->fts_statp->st_ino = D_INO (dp); + + /* Build a file name for fts_stat to stat. */ + if (ISSET(FTS_NOCHDIR)) { + p->fts_accpath = p->fts_path; + memmove(cp, p->fts_name, p->fts_namelen + 1); + } else + p->fts_accpath = p->fts_name; + + if (sp->fts_compar == NULL || ISSET(FTS_DEFER_STAT)) { + /* Record what fts_read will have to do with this + entry. In many cases, it will simply fts_stat it, + but we can take advantage of any d_type information + to optimize away the unnecessary stat calls. I.e., + if FTS_NOSTAT is in effect and we're not following + symlinks (FTS_PHYSICAL) and d_type indicates this + is *not* a directory, then we won't have to stat it + at all. If it *is* a directory, then (currently) + we stat it regardless, in order to get device and + inode numbers. Some day we might optimize that + away, too, for directories where d_ino is known to + be valid. */ + bool skip_stat = (ISSET(FTS_NOSTAT) + && DT_IS_KNOWN(dp) + && ! DT_MUST_BE(dp, DT_DIR) + && (ISSET(FTS_PHYSICAL) + || ! DT_MUST_BE(dp, DT_LNK))); + p->fts_info = FTS_NSOK; + /* Propagate dirent.d_type information back + to caller, when possible. */ + set_stat_type (p->fts_statp, D_TYPE (dp)); + fts_set_stat_required(p, !skip_stat); + } else { + p->fts_info = fts_stat(sp, p, false); + } + + /* We walk in directory order so "ls -f" doesn't get upset. */ + p->fts_link = NULL; + if (head == NULL) + head = tail = p; + else { + tail->fts_link = p; + tail = p; + } + + /* If there are many entries, no sorting function has been + specified, and this file system is of a type that may be + slow with a large number of entries, arrange to sort the + directory entries on increasing inode numbers. + + The NITEMS comparison uses ==, not >, because the test + needs to be tried at most once once, and NITEMS will exceed + the threshold after it is incremented below. */ + if (nitems == _FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD + && !sp->fts_compar) + sort_by_inode = dirent_inode_sort_may_be_useful (cur, dir_fd); + + ++nitems; + if (max_entries <= nitems) { + /* When there are too many dir entries, leave + fts_dirp open, so that a subsequent fts_read + can take up where we leave off. */ + goto break_without_closedir; + } + } + + if (cur->fts_dirp) + closedir_and_clear(cur->fts_dirp); + + break_without_closedir: + + /* + * If realloc() changed the address of the file name, adjust the + * addresses for the rest of the tree and the dir list. + */ + if (doadjust) + fts_padjust(sp, head); + + /* + * If not changing directories, reset the file name back to original + * state. + */ + if (ISSET(FTS_NOCHDIR)) { + if (len == sp->fts_pathlen || nitems == 0) + --cp; + *cp = '\0'; + } + + /* + * If descended after called from fts_children or after called from + * fts_read and nothing found, get back. At the root level we use + * the saved fd; if one of fts_open()'s arguments is a relative name + * to an empty directory, we wind up here with no other way back. If + * can't get back, we're done. + */ + if (!continue_readdir && descend && (type == BCHILD || !nitems) && + (cur->fts_level == FTS_ROOTLEVEL + ? restore_initial_cwd(sp) + : fts_safe_changedir(sp, cur->fts_parent, -1, ".."))) { + cur->fts_info = FTS_ERR; + SET(FTS_STOP); + fts_lfree(head); + return (NULL); + } + + /* If didn't find anything, return NULL. */ + if (!nitems) { + if (type == BREAD + && cur->fts_info != FTS_DNR && cur->fts_info != FTS_ERR) + cur->fts_info = FTS_DP; + fts_lfree(head); + return (NULL); + } + + if (sort_by_inode) { + sp->fts_compar = fts_compare_ino; + head = fts_sort (sp, head, nitems); + sp->fts_compar = NULL; + } + + /* Sort the entries. */ + if (sp->fts_compar && nitems > 1) + head = fts_sort(sp, head, nitems); + return (head); +} + +#if FTS_DEBUG + +/* Walk ->fts_parent links starting at E_CURR, until the root of the + current hierarchy. There should be a directory with dev/inode + matching those of AD. If not, print a lot of diagnostics. */ +static void +find_matching_ancestor (FTSENT const *e_curr, struct Active_dir const *ad) +{ + FTSENT const *ent; + for (ent = e_curr; ent->fts_level >= FTS_ROOTLEVEL; ent = ent->fts_parent) + { + if (ad->ino == ent->fts_statp->st_ino + && ad->dev == ent->fts_statp->st_dev) + return; + } + printf ("ERROR: tree dir, %s, not active\n", ad->fts_ent->fts_accpath); + printf ("active dirs:\n"); + for (ent = e_curr; + ent->fts_level >= FTS_ROOTLEVEL; ent = ent->fts_parent) + printf (" %s(%"PRIuMAX"/%"PRIuMAX") to %s(%"PRIuMAX"/%"PRIuMAX")...\n", + ad->fts_ent->fts_accpath, + (uintmax_t) ad->dev, + (uintmax_t) ad->ino, + ent->fts_accpath, + (uintmax_t) ent->fts_statp->st_dev, + (uintmax_t) ent->fts_statp->st_ino); +} + +void +fts_cross_check (FTS const *sp) +{ + FTSENT const *ent = sp->fts_cur; + FTSENT const *t; + if ( ! ISSET (FTS_TIGHT_CYCLE_CHECK)) + return; + + Dprintf (("fts-cross-check cur=%s\n", ent->fts_path)); + /* Make sure every parent dir is in the tree. */ + for (t = ent->fts_parent; t->fts_level >= FTS_ROOTLEVEL; t = t->fts_parent) + { + struct Active_dir ad; + ad.ino = t->fts_statp->st_ino; + ad.dev = t->fts_statp->st_dev; + if ( ! hash_lookup (sp->fts_cycle.ht, &ad)) + printf ("ERROR: active dir, %s, not in tree\n", t->fts_path); + } + + /* Make sure every dir in the tree is an active dir. + But ENT is not necessarily a directory. If so, just skip this part. */ + if (ent->fts_parent->fts_level >= FTS_ROOTLEVEL + && (ent->fts_info == FTS_DP + || ent->fts_info == FTS_D)) + { + struct Active_dir *ad; + for (ad = hash_get_first (sp->fts_cycle.ht); ad != NULL; + ad = hash_get_next (sp->fts_cycle.ht, ad)) + { + find_matching_ancestor (ent, ad); + } + } +} + +static bool +same_fd (int fd1, int fd2) +{ + struct stat sb1, sb2; + return (fstat (fd1, &sb1) == 0 + && fstat (fd2, &sb2) == 0 + && SAME_INODE (sb1, sb2)); +} + +static void +fd_ring_print (FTS const *sp, FILE *stream, char const *msg) +{ + I_ring const *fd_ring = &sp->fts_fd_ring; + unsigned int i = fd_ring->fts_front; + char *cwd = getcwdat (sp->fts_cwd_fd, NULL, 0); + fprintf (stream, "=== %s ========== %s\n", msg, cwd); + free (cwd); + if (i_ring_empty (fd_ring)) + return; + + while (true) + { + int fd = fd_ring->fts_fd_ring[i]; + if (fd < 0) + fprintf (stream, "%d: %d:\n", i, fd); + else + { + char *wd = getcwdat (fd, NULL, 0); + fprintf (stream, "%d: %d: %s\n", i, fd, wd); + free (wd); + } + if (i == fd_ring->fts_back) + break; + i = (i + I_RING_SIZE - 1) % I_RING_SIZE; + } +} + +/* Ensure that each file descriptor on the fd_ring matches a + parent, grandparent, etc. of the current working directory. */ +static void +fd_ring_check (FTS const *sp) +{ + if (!fts_debug) + return; + + /* Make a writable copy. */ + I_ring fd_w = sp->fts_fd_ring; + + int cwd_fd = sp->fts_cwd_fd; + cwd_fd = fcntl (cwd_fd, F_DUPFD_CLOEXEC, STDERR_FILENO + 1); + char *dot = getcwdat (cwd_fd, NULL, 0); + error (0, 0, "===== check ===== cwd: %s", dot); + free (dot); + while ( ! i_ring_empty (&fd_w)) + { + int fd = i_ring_pop (&fd_w); + if (0 <= fd) + { + int open_flags = O_SEARCH | O_CLOEXEC; + int parent_fd = openat (cwd_fd, "..", open_flags); + if (parent_fd < 0) + { + // Warn? + break; + } + if (!same_fd (fd, parent_fd)) + { + char *cwd = getcwdat (fd, NULL, 0); + error (0, errno, "ring : %s", cwd); + char *c2 = getcwdat (parent_fd, NULL, 0); + error (0, errno, "parent: %s", c2); + free (cwd); + free (c2); + fts_assert (0); + } + close (cwd_fd); + cwd_fd = parent_fd; + } + } + close (cwd_fd); +} +#endif + +static unsigned short int +internal_function +fts_stat(FTS *sp, register FTSENT *p, bool follow) +{ + struct stat *sbp = p->fts_statp; + + if (ISSET (FTS_LOGICAL) + || (ISSET (FTS_COMFOLLOW) && p->fts_level == FTS_ROOTLEVEL)) + follow = true; + + /* + * If doing a logical walk, or application requested FTS_FOLLOW, do + * a stat(2). If that fails, check for a non-existent symlink. If + * fail, set the errno from the stat call. + */ + int flags = follow ? 0 : AT_SYMLINK_NOFOLLOW; + if (fstatat (sp->fts_cwd_fd, p->fts_accpath, sbp, flags) < 0) + { + if (follow && errno == ENOENT + && 0 <= fstatat (sp->fts_cwd_fd, p->fts_accpath, sbp, + AT_SYMLINK_NOFOLLOW)) + { + __set_errno (0); + return FTS_SLNONE; + } + + p->fts_errno = errno; + memset (sbp, 0, sizeof *sbp); + return FTS_NS; + } + + if (S_ISDIR(sbp->st_mode)) { + if (ISDOT(p->fts_name)) { + /* Command-line "." and ".." are real directories. */ + return (p->fts_level == FTS_ROOTLEVEL ? FTS_D : FTS_DOT); + } + + return (FTS_D); + } + if (S_ISLNK(sbp->st_mode)) + return (FTS_SL); + if (S_ISREG(sbp->st_mode)) + return (FTS_F); + return (FTS_DEFAULT); +} + +static int +fts_compar (void const *a, void const *b) +{ + /* Convert A and B to the correct types, to pacify the compiler, and + for portability to bizarre hosts where "void const *" and "FTSENT + const **" differ in runtime representation. The comparison + function cannot modify *a and *b, but there is no compile-time + check for this. */ + FTSENT const **pa = (FTSENT const **) a; + FTSENT const **pb = (FTSENT const **) b; + return pa[0]->fts_fts->fts_compar (pa, pb); +} + +static FTSENT * +internal_function +fts_sort (FTS *sp, FTSENT *head, register size_t nitems) +{ + register FTSENT **ap, *p; + + /* On most modern hosts, void * and FTSENT ** have the same + run-time representation, and one can convert sp->fts_compar to + the type qsort expects without problem. Use the heuristic that + this is OK if the two pointer types are the same size, and if + converting FTSENT ** to long int is the same as converting + FTSENT ** to void * and then to long int. This heuristic isn't + valid in general but we don't know of any counterexamples. */ + FTSENT *dummy; + int (*compare) (void const *, void const *) = + ((sizeof &dummy == sizeof (void *) + && (long int) &dummy == (long int) (void *) &dummy) + ? (int (*) (void const *, void const *)) sp->fts_compar + : fts_compar); + + /* + * Construct an array of pointers to the structures and call qsort(3). + * Reassemble the array in the order returned by qsort. If unable to + * sort for memory reasons, return the directory entries in their + * current order. Allocate enough space for the current needs plus + * 40 so don't realloc one entry at a time. + */ + if (nitems > sp->fts_nitems) { + FTSENT **a; + + sp->fts_nitems = nitems + 40; + if (SIZE_MAX / sizeof *a < sp->fts_nitems + || ! (a = realloc (sp->fts_array, + sp->fts_nitems * sizeof *a))) { + free(sp->fts_array); + sp->fts_array = NULL; + sp->fts_nitems = 0; + return (head); + } + sp->fts_array = a; + } + for (ap = sp->fts_array, p = head; p; p = p->fts_link) + *ap++ = p; + qsort((void *)sp->fts_array, nitems, sizeof(FTSENT *), compare); + for (head = *(ap = sp->fts_array); --nitems; ++ap) + ap[0]->fts_link = ap[1]; + ap[0]->fts_link = NULL; + return (head); +} + +static FTSENT * +internal_function +fts_alloc (FTS *sp, const char *name, register size_t namelen) +{ + register FTSENT *p; + size_t len; + + /* + * The file name is a variable length array. Allocate the FTSENT + * structure and the file name in one chunk. + */ + len = FLEXSIZEOF(FTSENT, fts_name, namelen + 1); + if ((p = malloc(len)) == NULL) + return (NULL); + + /* Copy the name and guarantee NUL termination. */ + memcpy(p->fts_name, name, namelen); + p->fts_name[namelen] = '\0'; + + p->fts_namelen = namelen; + p->fts_fts = sp; + p->fts_path = sp->fts_path; + p->fts_errno = 0; + p->fts_dirp = NULL; + p->fts_flags = 0; + p->fts_instr = FTS_NOINSTR; + p->fts_number = 0; + p->fts_pointer = NULL; + return (p); +} + +static void +internal_function +fts_lfree (register FTSENT *head) +{ + register FTSENT *p; + + /* Free a linked list of structures. */ + while ((p = head)) { + head = head->fts_link; + if (p->fts_dirp) + closedir (p->fts_dirp); + free(p); + } +} + +/* + * Allow essentially unlimited file name lengths; find, rm, ls should + * all work on any tree. Most systems will allow creation of file + * names much longer than MAXPATHLEN, even though the kernel won't + * resolve them. Add the size (not just what's needed) plus 256 bytes + * so don't realloc the file name 2 bytes at a time. + */ +static bool +internal_function +fts_palloc (FTS *sp, size_t more) +{ + char *p; + size_t new_len = sp->fts_pathlen + more + 256; + + /* + * See if fts_pathlen would overflow. + */ + if (new_len < sp->fts_pathlen) { + free(sp->fts_path); + sp->fts_path = NULL; + __set_errno (ENAMETOOLONG); + return false; + } + sp->fts_pathlen = new_len; + p = realloc(sp->fts_path, sp->fts_pathlen); + if (p == NULL) { + free(sp->fts_path); + sp->fts_path = NULL; + return false; + } + sp->fts_path = p; + return true; +} + +/* + * When the file name is realloc'd, have to fix all of the pointers in + * structures already returned. + */ +static void +internal_function +fts_padjust (FTS *sp, FTSENT *head) +{ + FTSENT *p; + char *addr = sp->fts_path; + +#define ADJUST(p) do { \ + if ((p)->fts_accpath != (p)->fts_name) { \ + (p)->fts_accpath = \ + (char *)addr + ((p)->fts_accpath - (p)->fts_path); \ + } \ + (p)->fts_path = addr; \ +} while (0) + /* Adjust the current set of children. */ + for (p = sp->fts_child; p; p = p->fts_link) + ADJUST(p); + + /* Adjust the rest of the tree, including the current level. */ + for (p = head; p->fts_level >= FTS_ROOTLEVEL;) { + ADJUST(p); + p = p->fts_link ? p->fts_link : p->fts_parent; + } +} + +static size_t +internal_function _GL_ATTRIBUTE_PURE +fts_maxarglen (char * const *argv) +{ + size_t len, max; + + for (max = 0; *argv; ++argv) + if ((len = strlen(*argv)) > max) + max = len; + return (max + 1); +} + +/* + * Change to dir specified by fd or file name without getting + * tricked by someone changing the world out from underneath us. + * Assumes p->fts_statp->st_dev and p->fts_statp->st_ino are filled in. + * If FD is non-negative, expect it to be used after this function returns, + * and to be closed eventually. So don't pass e.g., 'dirfd(dirp)' and then + * do closedir(dirp), because that would invalidate the saved FD. + * Upon failure, close FD immediately and return nonzero. + */ +static int +internal_function +fts_safe_changedir (FTS *sp, FTSENT *p, int fd, char const *dir) +{ + int ret; + bool is_dotdot = dir && STREQ (dir, ".."); + int newfd; + + /* This clause handles the unusual case in which FTS_NOCHDIR + is specified, along with FTS_CWDFD. In that case, there is + no need to change even the virtual cwd file descriptor. + However, if FD is non-negative, we do close it here. */ + if (ISSET (FTS_NOCHDIR)) + { + if (ISSET (FTS_CWDFD) && 0 <= fd) + close (fd); + return 0; + } + + if (fd < 0 && is_dotdot && ISSET (FTS_CWDFD)) + { + /* When possible, skip the diropen and subsequent fstat+dev/ino + comparison. I.e., when changing to parent directory + (chdir ("..")), use a file descriptor from the ring and + save the overhead of diropen+fstat, as well as avoiding + failure when we lack "x" access to the virtual cwd. */ + if ( ! i_ring_empty (&sp->fts_fd_ring)) + { + int parent_fd; + fd_ring_print (sp, stderr, "pre-pop"); + parent_fd = i_ring_pop (&sp->fts_fd_ring); + if (0 <= parent_fd) + { + fd = parent_fd; + dir = NULL; + } + } + } + + newfd = fd; + if (fd < 0 && (newfd = diropen (sp, dir)) < 0) + return -1; + + /* The following dev/inode check is necessary if we're doing a + "logical" traversal (through symlinks, a la chown -L), if the + system lacks O_NOFOLLOW support, or if we're changing to ".." + (but not via a popped file descriptor). When changing to the + name "..", O_NOFOLLOW can't help. In general, when the target is + not "..", diropen's use of O_NOFOLLOW ensures we don't mistakenly + follow a symlink, so we can avoid the expense of this fstat. */ + if (ISSET(FTS_LOGICAL) || ! HAVE_WORKING_O_NOFOLLOW + || (dir && STREQ (dir, ".."))) + { + struct stat sb; + if (fstat(newfd, &sb)) + { + ret = -1; + goto bail; + } + if (p->fts_statp->st_dev != sb.st_dev + || p->fts_statp->st_ino != sb.st_ino) + { + __set_errno (ENOENT); /* disinformation */ + ret = -1; + goto bail; + } + } + + if (ISSET(FTS_CWDFD)) + { + cwd_advance_fd (sp, newfd, ! is_dotdot); + return 0; + } + + ret = fchdir(newfd); +bail: + if (fd < 0) + { + int oerrno = errno; + (void)close(newfd); + __set_errno (oerrno); + } + return ret; +} |