minix/external/bsd/libarchive/dist/tar/tree.c
Ben Gras 543adbed3a libarchive import
. clean and nbsd_ports managed import
	. also makes it shared
2012-05-02 13:31:48 +02:00

821 lines
20 KiB
C

/*-
* Copyright (c) 2003-2007 Tim Kientzle
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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 AUTHOR(S) 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.
*/
/*-
* This is a new directory-walking system that addresses a number
* of problems I've had with fts(3). In particular, it has no
* pathname-length limits (other than the size of 'int'), handles
* deep logical traversals, uses considerably less memory, and has
* an opaque interface (easier to modify in the future).
*
* Internally, it keeps a single list of "tree_entry" items that
* represent filesystem objects that require further attention.
* Non-directories are not kept in memory: they are pulled from
* readdir(), returned to the client, then freed as soon as possible.
* Any directory entry to be traversed gets pushed onto the stack.
*
* There is surprisingly little information that needs to be kept for
* each item on the stack. Just the name, depth (represented here as the
* string length of the parent directory's pathname), and some markers
* indicating how to get back to the parent (via chdir("..") for a
* regular dir or via fchdir(2) for a symlink).
*/
#include "bsdtar_platform.h"
__FBSDID("$FreeBSD: src/usr.bin/tar/tree.c,v 1.9 2008/11/27 05:49:52 kientzle Exp $");
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_DIRECT_H
#include <direct.h>
#endif
#ifdef HAVE_DIRENT_H
#include <dirent.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#if defined(HAVE_WINDOWS_H) && !defined(__CYGWIN__)
#include <windows.h>
#endif
#include "tree.h"
/*
* TODO:
* 1) Loop checking.
* 3) Arbitrary logical traversals by closing/reopening intermediate fds.
*/
struct tree_entry {
int depth;
struct tree_entry *next;
struct tree_entry *parent;
char *name;
size_t dirname_length;
dev_t dev;
ino_t ino;
int flags;
/* How to return back to the parent of a symlink. */
#ifdef HAVE_FCHDIR
int symlink_parent_fd;
#elif defined(_WIN32) && !defined(__CYGWIN__)
char *symlink_parent_path;
#else
#error fchdir function required.
#endif
};
/* Definitions for tree_entry.flags bitmap. */
#define isDir 1 /* This entry is a regular directory. */
#define isDirLink 2 /* This entry is a symbolic link to a directory. */
#define needsFirstVisit 4 /* This is an initial entry. */
#define needsDescent 8 /* This entry needs to be previsited. */
#define needsOpen 16 /* This is a directory that needs to be opened. */
#define needsAscent 32 /* This entry needs to be postvisited. */
/*
* On Windows, "first visit" is handled as a pattern to be handed to
* _findfirst(). This is consistent with Windows conventions that
* file patterns are handled within the application. On Posix,
* "first visit" is just returned to the client.
*/
/*
* Local data for this package.
*/
struct tree {
struct tree_entry *stack;
struct tree_entry *current;
#if defined(HAVE_WINDOWS_H) && !defined(__CYGWIN__)
HANDLE d;
BY_HANDLE_FILE_INFORMATION fileInfo;
#define INVALID_DIR_HANDLE INVALID_HANDLE_VALUE
WIN32_FIND_DATA _findData;
WIN32_FIND_DATA *findData;
#else
DIR *d;
#define INVALID_DIR_HANDLE NULL
struct dirent *de;
#endif
int flags;
int visit_type;
int tree_errno; /* Error code from last failed operation. */
/* Dynamically-sized buffer for holding path */
char *buff;
size_t buff_length;
const char *basename; /* Last path element */
size_t dirname_length; /* Leading dir length */
size_t path_length; /* Total path length */
int depth;
int openCount;
int maxOpenCount;
struct stat lst;
struct stat st;
};
/* Definitions for tree.flags bitmap. */
#define hasStat 16 /* The st entry is valid. */
#define hasLstat 32 /* The lst entry is valid. */
#define hasFileInfo 64 /* The Windows fileInfo entry is valid. */
#if defined(_WIN32) && !defined(__CYGWIN__)
static int
tree_dir_next_windows(struct tree *t, const char *pattern);
#else
static int
tree_dir_next_posix(struct tree *t);
#endif
#ifdef HAVE_DIRENT_D_NAMLEN
/* BSD extension; avoids need for a strlen() call. */
#define D_NAMELEN(dp) (dp)->d_namlen
#else
#define D_NAMELEN(dp) (strlen((dp)->d_name))
#endif
#include <stdio.h>
void
tree_dump(struct tree *t, FILE *out)
{
char buff[300];
struct tree_entry *te;
fprintf(out, "\tdepth: %d\n", t->depth);
fprintf(out, "\tbuff: %s\n", t->buff);
fprintf(out, "\tpwd: %s\n", getcwd(buff, sizeof(buff)));
fprintf(out, "\tbasename: %s\n", t->basename);
fprintf(out, "\tstack:\n");
for (te = t->stack; te != NULL; te = te->next) {
fprintf(out, "\t\t%s%d:\"%s\" %s%s%s%s%s%s\n",
t->current == te ? "*" : " ",
te->depth,
te->name,
te->flags & needsFirstVisit ? "V" : "",
te->flags & needsDescent ? "D" : "",
te->flags & needsOpen ? "O" : "",
te->flags & needsAscent ? "A" : "",
te->flags & isDirLink ? "L" : "",
(t->current == te && t->d) ? "+" : ""
);
}
}
/*
* Add a directory path to the current stack.
*/
static void
tree_push(struct tree *t, const char *path)
{
struct tree_entry *te;
te = malloc(sizeof(*te));
memset(te, 0, sizeof(*te));
te->next = t->stack;
te->parent = t->current;
if (te->parent)
te->depth = te->parent->depth + 1;
t->stack = te;
#ifdef HAVE_FCHDIR
te->symlink_parent_fd = -1;
te->name = strdup(path);
#elif defined(_WIN32) && !defined(__CYGWIN__)
te->symlink_parent_path = NULL;
te->name = strdup(path);
#endif
te->flags = needsDescent | needsOpen | needsAscent;
te->dirname_length = t->dirname_length;
}
/*
* Append a name to the current dir path.
*/
static void
tree_append(struct tree *t, const char *name, size_t name_length)
{
char *p;
size_t size_needed;
if (t->buff != NULL)
t->buff[t->dirname_length] = '\0';
/* Strip trailing '/' from name, unless entire name is "/". */
while (name_length > 1 && name[name_length - 1] == '/')
name_length--;
/* Resize pathname buffer as needed. */
size_needed = name_length + 1 + t->dirname_length;
if (t->buff_length < size_needed) {
if (t->buff_length < 1024)
t->buff_length = 1024;
while (t->buff_length < size_needed)
t->buff_length *= 2;
t->buff = realloc(t->buff, t->buff_length);
}
if (t->buff == NULL)
abort();
p = t->buff + t->dirname_length;
t->path_length = t->dirname_length + name_length;
/* Add a separating '/' if it's needed. */
if (t->dirname_length > 0 && p[-1] != '/') {
*p++ = '/';
t->path_length ++;
}
#if HAVE_STRNCPY_S
strncpy_s(p, t->buff_length - (p - t->buff), name, name_length);
#else
strncpy(p, name, name_length);
#endif
p[name_length] = '\0';
t->basename = p;
}
/*
* Open a directory tree for traversal.
*/
struct tree *
tree_open(const char *path)
{
#ifdef HAVE_FCHDIR
struct tree *t;
t = malloc(sizeof(*t));
memset(t, 0, sizeof(*t));
/* First item is set up a lot like a symlink traversal. */
tree_push(t, path);
t->stack->flags = needsFirstVisit | isDirLink | needsAscent;
t->stack->symlink_parent_fd = open(".", O_RDONLY);
t->openCount++;
t->d = INVALID_DIR_HANDLE;
return (t);
#elif defined(_WIN32) && !defined(__CYGWIN__)
struct tree *t;
char *cwd = _getcwd(NULL, 0);
char *pathname = strdup(path), *p, *base;
if (pathname == NULL)
abort();
for (p = pathname; *p != '\0'; ++p) {
if (*p == '\\')
*p = '/';
}
base = pathname;
t = malloc(sizeof(*t));
memset(t, 0, sizeof(*t));
/* First item is set up a lot like a symlink traversal. */
/* printf("Looking for wildcard in %s\n", path); */
/* TODO: wildcard detection here screws up on \\?\c:\ UNC names */
if (strchr(base, '*') || strchr(base, '?')) {
// It has a wildcard in it...
// Separate the last element.
p = strrchr(base, '/');
if (p != NULL) {
*p = '\0';
chdir(base);
tree_append(t, base, p - base);
t->dirname_length = t->path_length;
base = p + 1;
}
}
tree_push(t, base);
free(pathname);
t->stack->flags = needsFirstVisit | isDirLink | needsAscent;
t->stack->symlink_parent_path = cwd;
t->d = INVALID_DIR_HANDLE;
return (t);
#endif
}
/*
* We've finished a directory; ascend back to the parent.
*/
static int
tree_ascend(struct tree *t)
{
struct tree_entry *te;
int r = 0;
te = t->stack;
t->depth--;
if (te->flags & isDirLink) {
#ifdef HAVE_FCHDIR
if (fchdir(te->symlink_parent_fd) != 0) {
t->tree_errno = errno;
r = TREE_ERROR_FATAL;
}
close(te->symlink_parent_fd);
#elif defined(_WIN32) && !defined(__CYGWIN__)
if (SetCurrentDirectory(te->symlink_parent_path) == 0) {
t->tree_errno = errno;
r = TREE_ERROR_FATAL;
}
free(te->symlink_parent_path);
te->symlink_parent_path = NULL;
#endif
t->openCount--;
} else {
#if defined(_WIN32) && !defined(__CYGWIN__)
if (SetCurrentDirectory("..") == 0) {
#else
if (chdir("..") != 0) {
#endif
t->tree_errno = errno;
r = TREE_ERROR_FATAL;
}
}
return (r);
}
/*
* Pop the working stack.
*/
static void
tree_pop(struct tree *t)
{
struct tree_entry *te;
if (t->buff)
t->buff[t->dirname_length] = '\0';
if (t->stack == t->current && t->current != NULL)
t->current = t->current->parent;
te = t->stack;
t->stack = te->next;
t->dirname_length = te->dirname_length;
if (t->buff) {
t->basename = t->buff + t->dirname_length;
while (t->basename[0] == '/')
t->basename++;
}
free(te->name);
free(te);
}
/*
* Get the next item in the tree traversal.
*/
int
tree_next(struct tree *t)
{
int r;
/* If we're called again after a fatal error, that's an API
* violation. Just crash now. */
if (t->visit_type == TREE_ERROR_FATAL) {
fprintf(stderr, "Unable to continue traversing"
" directory heirarchy after a fatal error.");
abort();
}
while (t->stack != NULL) {
/* If there's an open dir, get the next entry from there. */
if (t->d != INVALID_DIR_HANDLE) {
#if defined(_WIN32) && !defined(__CYGWIN__)
r = tree_dir_next_windows(t, NULL);
#else
r = tree_dir_next_posix(t);
#endif
if (r == 0)
continue;
return (r);
}
if (t->stack->flags & needsFirstVisit) {
#if defined(_WIN32) && !defined(__CYGWIN__)
char *d = t->stack->name;
t->stack->flags &= ~needsFirstVisit;
if (strchr(d, '*') || strchr(d, '?')) {
r = tree_dir_next_windows(t, d);
if (r == 0)
continue;
return (r);
}
// Not a pattern, handle it as-is...
#endif
/* Top stack item needs a regular visit. */
t->current = t->stack;
tree_append(t, t->stack->name, strlen(t->stack->name));
//t->dirname_length = t->path_length;
//tree_pop(t);
t->stack->flags &= ~needsFirstVisit;
return (t->visit_type = TREE_REGULAR);
} else if (t->stack->flags & needsDescent) {
/* Top stack item is dir to descend into. */
t->current = t->stack;
tree_append(t, t->stack->name, strlen(t->stack->name));
t->stack->flags &= ~needsDescent;
/* If it is a link, set up fd for the ascent. */
if (t->stack->flags & isDirLink) {
#ifdef HAVE_FCHDIR
t->stack->symlink_parent_fd = open(".", O_RDONLY);
t->openCount++;
if (t->openCount > t->maxOpenCount)
t->maxOpenCount = t->openCount;
#elif defined(_WIN32) && !defined(__CYGWIN__)
t->stack->symlink_parent_path = _getcwd(NULL, 0);
#endif
}
t->dirname_length = t->path_length;
#if defined(_WIN32) && !defined(__CYGWIN__)
if (t->path_length == 259 || !SetCurrentDirectory(t->stack->name) != 0)
#else
if (chdir(t->stack->name) != 0)
#endif
{
/* chdir() failed; return error */
tree_pop(t);
t->tree_errno = errno;
return (t->visit_type = TREE_ERROR_DIR);
}
t->depth++;
return (t->visit_type = TREE_POSTDESCENT);
} else if (t->stack->flags & needsOpen) {
t->stack->flags &= ~needsOpen;
#if defined(_WIN32) && !defined(__CYGWIN__)
r = tree_dir_next_windows(t, "*");
#else
r = tree_dir_next_posix(t);
#endif
if (r == 0)
continue;
return (r);
} else if (t->stack->flags & needsAscent) {
/* Top stack item is dir and we're done with it. */
r = tree_ascend(t);
tree_pop(t);
t->visit_type = r != 0 ? r : TREE_POSTASCENT;
return (t->visit_type);
} else {
/* Top item on stack is dead. */
tree_pop(t);
t->flags &= ~hasLstat;
t->flags &= ~hasStat;
}
}
return (t->visit_type = 0);
}
#if defined(_WIN32) && !defined(__CYGWIN__)
static int
tree_dir_next_windows(struct tree *t, const char *pattern)
{
const char *name;
size_t namelen;
int r;
for (;;) {
if (pattern != NULL) {
t->d = FindFirstFile(pattern, &t->_findData);
if (t->d == INVALID_DIR_HANDLE) {
r = tree_ascend(t); /* Undo "chdir" */
tree_pop(t);
t->tree_errno = errno;
t->visit_type = r != 0 ? r : TREE_ERROR_DIR;
return (t->visit_type);
}
t->findData = &t->_findData;
pattern = NULL;
} else if (!FindNextFile(t->d, &t->_findData)) {
FindClose(t->d);
t->d = INVALID_DIR_HANDLE;
t->findData = NULL;
return (0);
}
name = t->findData->cFileName;
namelen = strlen(name);
t->flags &= ~hasLstat;
t->flags &= ~hasStat;
if (name[0] == '.' && name[1] == '\0')
continue;
if (name[0] == '.' && name[1] == '.' && name[2] == '\0')
continue;
tree_append(t, name, namelen);
return (t->visit_type = TREE_REGULAR);
}
}
#else
static int
tree_dir_next_posix(struct tree *t)
{
int r;
const char *name;
size_t namelen;
if (t->d == NULL) {
if ((t->d = opendir(".")) == NULL) {
r = tree_ascend(t); /* Undo "chdir" */
tree_pop(t);
t->tree_errno = errno;
t->visit_type = r != 0 ? r : TREE_ERROR_DIR;
return (t->visit_type);
}
}
for (;;) {
t->de = readdir(t->d);
if (t->de == NULL) {
closedir(t->d);
t->d = INVALID_DIR_HANDLE;
return (0);
}
name = t->de->d_name;
namelen = D_NAMELEN(t->de);
t->flags &= ~hasLstat;
t->flags &= ~hasStat;
if (name[0] == '.' && name[1] == '\0')
continue;
if (name[0] == '.' && name[1] == '.' && name[2] == '\0')
continue;
tree_append(t, name, namelen);
return (t->visit_type = TREE_REGULAR);
}
}
#endif
/*
* Return error code.
*/
int
tree_errno(struct tree *t)
{
return (t->tree_errno);
}
/*
* Called by the client to mark the directory just returned from
* tree_next() as needing to be visited.
*/
void
tree_descend(struct tree *t)
{
if (t->visit_type != TREE_REGULAR)
return;
if (tree_current_is_physical_dir(t)) {
tree_push(t, t->basename);
t->stack->flags |= isDir;
} else if (tree_current_is_dir(t)) {
tree_push(t, t->basename);
t->stack->flags |= isDirLink;
}
}
/*
* Get the stat() data for the entry just returned from tree_next().
*/
const struct stat *
tree_current_stat(struct tree *t)
{
if (!(t->flags & hasStat)) {
if (stat(tree_current_access_path(t), &t->st) != 0)
return NULL;
t->flags |= hasStat;
}
return (&t->st);
}
#if defined(HAVE_WINDOWS_H) && !defined(__CYGWIN__)
const BY_HANDLE_FILE_INFORMATION *
tree_current_file_information(struct tree *t)
{
if (!(t->flags & hasFileInfo)) {
HANDLE h = CreateFile(tree_current_access_path(t),
0, 0, NULL,
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT,
NULL);
if (h == INVALID_HANDLE_VALUE)
return NULL;
if (!GetFileInformationByHandle(h, &t->fileInfo)) {
CloseHandle(h);
return NULL;
}
CloseHandle(h);
t->flags |= hasFileInfo;
}
return (&t->fileInfo);
}
#endif
/*
* Get the lstat() data for the entry just returned from tree_next().
*/
const struct stat *
tree_current_lstat(struct tree *t)
{
#if defined(_WIN32) && !defined(__CYGWIN__)
return (tree_current_stat(t));
#else
if (!(t->flags & hasLstat)) {
if (lstat(tree_current_access_path(t), &t->lst) != 0)
return NULL;
t->flags |= hasLstat;
}
return (&t->lst);
#endif
}
/*
* Test whether current entry is a dir or link to a dir.
*/
int
tree_current_is_dir(struct tree *t)
{
#if defined(_WIN32) && !defined(__CYGWIN__)
if (t->findData)
return (t->findData->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY);
if (tree_current_file_information(t))
return (t->fileInfo.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY);
return (0);
#else
const struct stat *st;
/*
* If we already have lstat() info, then try some
* cheap tests to determine if this is a dir.
*/
if (t->flags & hasLstat) {
/* If lstat() says it's a dir, it must be a dir. */
if (S_ISDIR(tree_current_lstat(t)->st_mode))
return 1;
/* Not a dir; might be a link to a dir. */
/* If it's not a link, then it's not a link to a dir. */
if (!S_ISLNK(tree_current_lstat(t)->st_mode))
return 0;
/*
* It's a link, but we don't know what it's a link to,
* so we'll have to use stat().
*/
}
st = tree_current_stat(t);
/* If we can't stat it, it's not a dir. */
if (st == NULL)
return 0;
/* Use the definitive test. Hopefully this is cached. */
return (S_ISDIR(st->st_mode));
#endif
}
/*
* Test whether current entry is a physical directory. Usually, we
* already have at least one of stat() or lstat() in memory, so we
* use tricks to try to avoid an extra trip to the disk.
*/
int
tree_current_is_physical_dir(struct tree *t)
{
#if defined(_WIN32) && !defined(__CYGWIN__)
if (tree_current_is_physical_link(t))
return (0);
return (tree_current_is_dir(t));
#else
const struct stat *st;
/*
* If stat() says it isn't a dir, then it's not a dir.
* If stat() data is cached, this check is free, so do it first.
*/
if ((t->flags & hasStat)
&& (!S_ISDIR(tree_current_stat(t)->st_mode)))
return 0;
/*
* Either stat() said it was a dir (in which case, we have
* to determine whether it's really a link to a dir) or
* stat() info wasn't available. So we use lstat(), which
* hopefully is already cached.
*/
st = tree_current_lstat(t);
/* If we can't stat it, it's not a dir. */
if (st == NULL)
return 0;
/* Use the definitive test. Hopefully this is cached. */
return (S_ISDIR(st->st_mode));
#endif
}
/*
* Test whether current entry is a symbolic link.
*/
int
tree_current_is_physical_link(struct tree *t)
{
#if defined(_WIN32) && !defined(__CYGWIN__)
#ifndef IO_REPARSE_TAG_SYMLINK
/* Old SDKs do not provide IO_REPARSE_TAG_SYMLINK */
#define IO_REPARSE_TAG_SYMLINK 0xA000000CL
#endif
if (t->findData)
return ((t->findData->dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)
&& (t->findData->dwReserved0 == IO_REPARSE_TAG_SYMLINK));
return (0);
#else
const struct stat *st = tree_current_lstat(t);
if (st == NULL)
return 0;
return (S_ISLNK(st->st_mode));
#endif
}
/*
* Return the access path for the entry just returned from tree_next().
*/
const char *
tree_current_access_path(struct tree *t)
{
return (t->basename);
}
/*
* Return the full path for the entry just returned from tree_next().
*/
const char *
tree_current_path(struct tree *t)
{
return (t->buff);
}
/*
* Return the length of the path for the entry just returned from tree_next().
*/
size_t
tree_current_pathlen(struct tree *t)
{
return (t->path_length);
}
/*
* Return the nesting depth of the entry just returned from tree_next().
*/
int
tree_current_depth(struct tree *t)
{
return (t->depth);
}
/*
* Terminate the traversal and release any resources.
*/
void
tree_close(struct tree *t)
{
/* Release anything remaining in the stack. */
while (t->stack != NULL)
tree_pop(t);
free(t->buff);
/* TODO: Ensure that premature close() resets cwd */
#if 0
#ifdef HAVE_FCHDIR
if (t->initialDirFd >= 0) {
int s = fchdir(t->initialDirFd);
(void)s; /* UNUSED */
close(t->initialDirFd);
t->initialDirFd = -1;
}
#elif defined(_WIN32) && !defined(__CYGWIN__)
if (t->initialDir != NULL) {
SetCurrentDir(t->initialDir);
free(t->initialDir);
t->initialDir = NULL;
}
#endif
#endif
free(t);
}