/* Traverse a file hierarchy.
- Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2004-2009 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
#endif
#include <fcntl.h>
#include <errno.h>
-#include "dirfd.h"
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#if ! _LIBC
# include "fcntl--.h"
-# include "lstat.h"
-# include "openat.h"
+# include "dirent--.h"
# include "unistd--.h"
+/* FIXME - use fcntl(F_DUPFD_CLOEXEC)/openat(O_CLOEXEC) once they are
+ supported. */
+# include "cloexec.h"
+# include "openat.h"
# include "same-inode.h"
#endif
# 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 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,
# define __set_errno(Val) errno = (Val)
#endif
-#ifndef __attribute__
-# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__
-# define __attribute__(x) /* empty */
-# endif
-#endif
-
-#ifndef ATTRIBUTE_UNUSED
-# define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
-#endif
-
/* If this host provides the openat function, then we can avoid
attempting to open "." in some initialization code below. */
#ifdef HAVE_OPENAT
# define SIZE_MAX ((size_t) -1)
#endif
-#ifndef O_DIRECTORY
-# define O_DIRECTORY 0
-#endif
-
#define ISDOT(a) (a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))
#define STREQ(a, b) (strcmp ((a), (b)) == 0)
internal_function
opendirat (int fd, char const *dir)
{
- int new_fd = openat (fd, dir, O_RDONLY);
+ int new_fd = openat (fd, dir,
+ O_RDONLY | O_DIRECTORY | O_NOCTTY | O_NONBLOCK);
DIR *dirp;
if (new_fd < 0)
return NULL;
+ set_cloexec_flag (new_fd, true);
dirp = fdopendir (new_fd);
if (dirp == NULL)
{
int open_flags = (O_RDONLY | O_DIRECTORY | O_NOCTTY | O_NONBLOCK
| (ISSET (FTS_PHYSICAL) ? O_NOFOLLOW : 0));
- return (ISSET (FTS_CWDFD)
- ? openat (sp->fts_cwd_fd, dir, open_flags)
- : open (dir, open_flags));
+ int fd = (ISSET (FTS_CWDFD)
+ ? openat (sp->fts_cwd_fd, dir, open_flags)
+ : open (dir, open_flags));
+ if (0 <= fd)
+ set_cloexec_flag (fd, true);
+ return fd;
}
FTS *
if (ISSET(FTS_CWDFD))
{
if (0 <= sp->fts_cwd_fd)
- close (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;
- close(sp->fts_rfd);
+
+ /* 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 GNULIB_FTS
+ if (sp->fts_leaf_optimization_works_ht)
+ hash_free (sp->fts_leaf_optimization_works_ht);
+#endif
+
free_dir (sp);
/* Free up the stream pointer. */
return (0);
}
+#if defined __linux__ \
+ && 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_TMPFS 0x1021994
+# define S_MAGIC_NFS 0x6969
+# define S_MAGIC_REISERFS 0x52654973
+# define S_MAGIC_PROC 0x9FA0
+
+/* Return false if it is easy to determine the file system type of
+ the directory on which DIR_FD is open, and sorting dirents on
+ inode numbers is known not to improve traversal performance with
+ that type of file system. Otherwise, return true. */
+static bool
+dirent_inode_sort_may_be_useful (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. */
+ struct statfs fs_buf;
+
+ /* If fstatfs fails, assume sorting would be useful. */
+ if (fstatfs (dir_fd, &fs_buf) != 0)
+ return true;
+
+ /* FIXME: what about when f_type is not an integral type?
+ deal with that if/when it's encountered. */
+ switch (fs_buf.f_type)
+ {
+ case S_MAGIC_TMPFS:
+ case S_MAGIC_NFS:
+ /* On a file system of any of these types, sorting
+ is unnecessary, and hence wasteful. */
+ return false;
+
+ default:
+ return true;
+ }
+}
+
+/* Given a file descriptor DIR_FD open on a directory D,
+ return true if it is valid to apply the leaf-optimization
+ technique of counting directories in D via stat.st_nlink. */
+static bool
+leaf_optimization_applies (int dir_fd)
+{
+ struct statfs fs_buf;
+
+ /* If fstatfs fails, assume we can't use the optimization. */
+ if (fstatfs (dir_fd, &fs_buf) != 0)
+ return false;
+
+ /* FIXME: do we need to detect AFS mount points? I doubt it,
+ unless fstatfs can report S_MAGIC_REISERFS for such a directory. */
+
+ switch (fs_buf.f_type)
+ {
+ /* List here the file system types that lack useable dirent.d_type
+ info, yet for which the optimization does apply. */
+ case S_MAGIC_REISERFS:
+ return true;
+
+ case S_MAGIC_PROC:
+ /* Explicitly listing this or any other file system type for which
+ the optimization is not applicable is not necessary, but we leave
+ it here to document the risk. Per http://bugs.debian.org/143111,
+ /proc may have bogus stat.st_nlink values. */
+ /* fall through */
+ default:
+ return false;
+ }
+}
+
+#else
+static bool
+dirent_inode_sort_may_be_useful (int dir_fd _UNUSED_PARAMETER_) { return true; }
+static bool
+leaf_optimization_applies (int dir_fd _UNUSED_PARAMETER_) { return false; }
+#endif
+
+#if GNULIB_FTS
+/* link-count-optimization entry:
+ map an stat.st_dev number to a boolean: leaf_optimization_works */
+struct LCO_ent
+{
+ dev_t st_dev;
+ bool opt_ok;
+};
+
+/* 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 { LCO_HT_INITIAL_SIZE = 13 };
+
+static size_t
+LCO_hash (void const *x, size_t table_size)
+{
+ struct LCO_ent const *ax = x;
+ return (uintmax_t) ax->st_dev % table_size;
+}
+
+static bool
+LCO_compare (void const *x, void const *y)
+{
+ struct LCO_ent const *ax = x;
+ struct LCO_ent const *ay = y;
+ return ax->st_dev == ay->st_dev;
+}
+
+/* Ask the same question as leaf_optimization_applies, but query
+ the cache first (FTS.fts_leaf_optimization_works_ht), and if necessary,
+ update that cache. */
+static bool
+link_count_optimize_ok (FTSENT const *p)
+{
+ FTS *sp = p->fts_fts;
+ Hash_table *h = sp->fts_leaf_optimization_works_ht;
+ struct LCO_ent tmp;
+ struct LCO_ent *ent;
+ bool opt_ok;
+ struct LCO_ent *t2;
+
+ /* 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 false;
+
+ /* map st_dev to the boolean, leaf_optimization_works */
+ if (h == NULL)
+ {
+ h = sp->fts_leaf_optimization_works_ht
+ = hash_initialize (LCO_HT_INITIAL_SIZE, NULL, LCO_hash,
+ LCO_compare, free);
+ if (h == NULL)
+ return false;
+ }
+ tmp.st_dev = p->fts_statp->st_dev;
+ ent = hash_lookup (h, &tmp);
+ if (ent)
+ return ent->opt_ok;
+
+ /* Look-up failed. Query directly and cache the result. */
+ t2 = malloc (sizeof *t2);
+ if (t2 == NULL)
+ return false;
+
+ /* Is it ok to perform the optimization in the dir, FTS_CWD_FD? */
+ opt_ok = leaf_optimization_applies (sp->fts_cwd_fd);
+ t2->opt_ok = opt_ok;
+ t2->st_dev = p->fts_statp->st_dev;
+
+ ent = hash_insert (h, t2);
+ if (ent == NULL)
+ {
+ /* insertion failed */
+ free (t2);
+ return false;
+ }
+ fts_assert (ent == t2);
+
+ return opt_ok;
+}
+#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".
SET(FTS_STOP);
return (NULL);
}
+ free_dir(sp);
fts_load(sp, p);
+ setup_dir(sp);
goto check_for_dir;
}
if (p->fts_info == FTS_NSOK)
{
if (p->fts_statp->st_size == FTS_STAT_REQUIRED)
- p->fts_info = fts_stat(sp, p, false);
+ {
+ FTSENT *parent = p->fts_parent;
+ if (FTS_ROOTLEVEL < p->fts_level
+ /* ->fts_n_dirs_remaining is not valid
+ for command-line-specified names. */
+ && parent->fts_n_dirs_remaining == 0
+ && ISSET(FTS_NOSTAT)
+ && ISSET(FTS_PHYSICAL)
+ && link_count_optimize_ok (parent))
+ {
+ /* nothing more needed */
+ }
+ else
+ {
+ p->fts_info = fts_stat(sp, p, false);
+ if (S_ISDIR(p->fts_statp->st_mode)
+ && p->fts_level != FTS_ROOTLEVEL
+ && parent->fts_n_dirs_remaining)
+ parent->fts_n_dirs_remaining--;
+ }
+ }
else
fts_assert (p->fts_statp->st_size == FTS_NO_STAT_REQUIRED);
}
*/
/* ARGSUSED */
int
-fts_set(FTS *sp ATTRIBUTE_UNUSED, FTSENT *p, int instr)
+fts_set(FTS *sp _UNUSED_PARAMETER_, FTSENT *p, int instr)
{
if (instr != 0 && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
instr != FTS_NOINSTR && instr != FTS_SKIP) {
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 (a[0]->fts_statp->st_ino < b[0]->fts_statp->st_ino ? -1
+ : b[0]->fts_statp->st_ino < a[0]->fts_statp->st_ino ? 1 : 0);
+}
+
+/* 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;
+}
+
/*
* 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
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;
+ }
+ }
/*
* Nlinks is the number of possible entries of type directory in the
if (nlinks || type == BREAD) {
int dir_fd = dirfd(dirp);
if (ISSET(FTS_CWDFD) && 0 <= dir_fd)
- dir_fd = dup (dir_fd);
+ {
+ dir_fd = dup (dir_fd);
+ set_cloexec_flag (dir_fd, true);
+ }
if (dir_fd < 0 || fts_safe_changedir(sp, cur, dir_fd, NULL)) {
if (nlinks && type == BREAD)
cur->fts_errno = errno;
new_len = len + _D_EXACT_NAMLEN (dp);
if (new_len < len) {
/*
- * In the unlikely even that we would end up
+ * 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.
if (dp->d_type == DT_WHT)
p->fts_flags |= FTS_ISW;
#endif
+ /* 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)) {
&& DT_IS_KNOWN(dp)
&& ! DT_MUST_BE(dp, DT_DIR));
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);
- is_dir = (ISSET(FTS_PHYSICAL) && ISSET(FTS_NOSTAT)
+ is_dir = (ISSET(FTS_PHYSICAL)
&& DT_MUST_BE(dp, DT_DIR));
} else {
p->fts_info = fts_stat(sp, p, false);
return (NULL);
}
+ /* 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, then sort the directory entries on increasing
+ inode numbers. */
+ if (nitems > _FTS_INODE_SORT_DIR_ENTRIES_THRESHOLD
+ && !sp->fts_compar
+ && ISSET (FTS_CWDFD)
+ && dirent_inode_sort_may_be_useful (sp->fts_cwd_fd)) {
+ 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);
}
if (S_ISDIR(sbp->st_mode)) {
+ p->fts_n_dirs_remaining = (sbp->st_nlink
+ - (ISSET(FTS_SEEDOT) ? 0 : 2));
if (ISDOT(p->fts_name)) {
/* Command-line "." and ".." are real directories. */
return (p->fts_level == FTS_ROOTLEVEL ? FTS_D : FTS_DOT);
projects / gnulib.git / blobdiff