[wimlib] / src / capture_common.c

/*
 * capture_common.c - Mostly code to handle excluding paths from capture.
 */

/*
 * Copyright (C) 2013, 2014 Eric Biggers
 *
 * This file is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 3 of the License, or (at your option) any
 * later version.
 *
 * This file 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 Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this file; if not, see http://www.gnu.org/licenses/.
 */

#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#include <string.h>

#include "wimlib/blob_table.h"
#include "wimlib/capture.h"
#include "wimlib/dentry.h"
#include "wimlib/error.h"
#include "wimlib/paths.h"
#include "wimlib/pattern.h"
#include "wimlib/progress.h"
#include "wimlib/textfile.h"

/*
 * Tally a file (or directory) that has been scanned for a capture operation,
 * and possibly call the progress function provided by the library user.
 *
 * @params
 *      Flags, optional progress function, and progress data for the capture
 *      operation.
 * @status
 *      Status of the scanned file.
 * @inode
 *      If @status is WIMLIB_SCAN_DENTRY_OK, this is a pointer to the WIM inode
 *      that has been created for the scanned file.  The first time the file is
 *      seen, inode->i_nlink will be 1.  On subsequent visits of the same inode
 *      via additional hard links, inode->i_nlink will be greater than 1.
 */
int
do_capture_progress(struct capture_params *params, int status,
                    const struct wim_inode *inode)
{
        switch (status) {
        case WIMLIB_SCAN_DENTRY_OK:
                if (!(params->add_flags & WIMLIB_ADD_FLAG_VERBOSE))
                        return 0;
                break;
        case WIMLIB_SCAN_DENTRY_UNSUPPORTED:
        case WIMLIB_SCAN_DENTRY_EXCLUDED:
        case WIMLIB_SCAN_DENTRY_FIXED_SYMLINK:
        case WIMLIB_SCAN_DENTRY_NOT_FIXED_SYMLINK:
                if (!(params->add_flags & WIMLIB_ADD_FLAG_EXCLUDE_VERBOSE))
                        return 0;
                break;
        }
        params->progress.scan.status = status;
        if (status == WIMLIB_SCAN_DENTRY_OK) {

                /* The first time the inode is seen, tally all its streams.  */
                if (inode->i_nlink == 1) {
                        for (unsigned i = 0; i < inode->i_num_streams; i++) {
                                const struct blob_descriptor *blob =
                                        stream_blob_resolved(&inode->i_streams[i]);
                                if (blob)
                                        params->progress.scan.num_bytes_scanned += blob->size;
                        }
                }

                /* Tally the file itself, counting every hard link.  It's
                 * debatable whether every link should be counted, but counting
                 * every link makes the statistics consistent with the ones
                 * placed in the FILECOUNT and DIRCOUNT elements of the WIM
                 * file's XML document.  It also avoids possible user confusion
                 * if the number of files reported were to be lower than that
                 * displayed by some other software such as file browsers.  */
                if (inode_is_directory(inode))
                        params->progress.scan.num_dirs_scanned++;
                else
                        params->progress.scan.num_nondirs_scanned++;
        }

        /* Call the user-provided progress function.  */
        return call_progress(params->progfunc, WIMLIB_PROGRESS_MSG_SCAN_DENTRY,
                             &params->progress, params->progctx);
}

/*
 * Given a null-terminated pathname pattern @pat that has been read from line
 * @line_no of the file @path, validate and canonicalize the pattern.
 *
 * On success, returns 0.
 * On failure, returns WIMLIB_ERR_INVALID_CAPTURE_CONFIG.
 * In either case, @pat may have been modified in-place (and possibly
 * shortened).
 */
int
mangle_pat(tchar *pat, const tchar *path, unsigned long line_no)
{
        if (!is_any_path_separator(pat[0]) &&
            pat[0] != T('\0') && pat[1] == T(':'))
        {
                /* Pattern begins with drive letter.  */

                if (!is_any_path_separator(pat[2])) {
                        /* Something like c:file, which is actually a path
                         * relative to the current working directory on the c:
                         * drive.  We require paths with drive letters to be
                         * absolute.  */
                        ERROR("%"TS":%lu: Invalid pattern \"%"TS"\":\n"
                              "        Patterns including drive letters must be absolute!\n"
                              "        Maybe try \"%"TC":%"TC"%"TS"\"?\n",
                              path, line_no, pat,
                              pat[0], OS_PREFERRED_PATH_SEPARATOR, &pat[2]);
                        return WIMLIB_ERR_INVALID_CAPTURE_CONFIG;
                }

                WARNING("%"TS":%lu: Pattern \"%"TS"\" starts with a drive "
                        "letter, which is being removed.",
                        path, line_no, pat);

                /* Strip the drive letter.  */
                tmemmove(pat, pat + 2, tstrlen(pat + 2) + 1);
        }

        /* Collapse consecutive path separators, and translate both / and \ into
         * / (UNIX) or \ (Windows).
         *
         * Note: we expect that this function produces patterns that can be used
         * for both filesystem paths and WIM paths, so the desired path
         * separators must be the same.  */
        STATIC_ASSERT(OS_PREFERRED_PATH_SEPARATOR == WIM_PATH_SEPARATOR);
        do_canonicalize_path(pat, pat);

        /* Relative patterns can only match file names, so they must be
         * single-component only.  */
        if (pat[0] != OS_PREFERRED_PATH_SEPARATOR &&
            tstrchr(pat, OS_PREFERRED_PATH_SEPARATOR))
        {
                ERROR("%"TS":%lu: Invalid pattern \"%"TS"\":\n"
                      "        Relative patterns can only include one path component!\n"
                      "        Maybe try \"%"TC"%"TS"\"?",
                      path, line_no, pat, OS_PREFERRED_PATH_SEPARATOR, pat);
                return WIMLIB_ERR_INVALID_CAPTURE_CONFIG;
        }

        return 0;
}

/*
 * Read, parse, and validate a capture configuration file from either an on-disk
 * file or an in-memory buffer.
 *
 * To read from a file, specify @config_file, and use NULL for @buf.
 * To read from a buffer, specify @buf and @bufsize.
 *
 * @config must be initialized to all 0's.
 *
 * On success, 0 will be returned, and the resulting capture configuration will
 * be stored in @config.
 *
 * On failure, a positive error code will be returned, and the contents of
 * @config will be invalidated.
 */
int
read_capture_config(const tchar *config_file, const void *buf,
                    size_t bufsize, struct capture_config *config)
{
        int ret;

        /* [PrepopulateList] is used for apply, not capture.  But since we do
         * understand it, recognize it, thereby avoiding the unrecognized
         * section warning, but discard the resulting strings.
         *
         * We currently ignore [CompressionExclusionList] and
         * [CompressionFolderList].  This is a known issue that doesn't seem to
         * have any real consequences, so don't issue warnings about not
         * recognizing those sections.  */
        STRING_SET(prepopulate_pats);
        STRING_SET(compression_exclusion_pats);
        STRING_SET(compression_folder_pats);

        struct text_file_section sections[] = {
                {T("ExclusionList"),
                        &config->exclusion_pats},
                {T("ExclusionException"),
                        &config->exclusion_exception_pats},
                {T("PrepopulateList"),
                        &prepopulate_pats},
                {T("CompressionExclusionList"),
                        &compression_exclusion_pats},
                {T("CompressionFolderList"),
                        &compression_folder_pats},
        };
        void *mem;

        ret = do_load_text_file(config_file, buf, bufsize, &mem,
                                sections, ARRAY_LEN(sections),
                                LOAD_TEXT_FILE_REMOVE_QUOTES, mangle_pat);
        if (ret) {
                ERROR("Failed to load capture configuration file \"%"TS"\"",
                      config_file);
                switch (ret) {
                case WIMLIB_ERR_INVALID_UTF8_STRING:
                case WIMLIB_ERR_INVALID_UTF16_STRING:
                        ERROR("Note: the capture configuration file must be "
                              "valid UTF-8 or UTF-16LE");
                        ret = WIMLIB_ERR_INVALID_CAPTURE_CONFIG;
                        break;
                case WIMLIB_ERR_OPEN:
                case WIMLIB_ERR_STAT:
                case WIMLIB_ERR_NOMEM:
                case WIMLIB_ERR_READ:
                        ret = WIMLIB_ERR_UNABLE_TO_READ_CAPTURE_CONFIG;
                        break;
                }
                return ret;
        }

        FREE(prepopulate_pats.strings);
        FREE(compression_exclusion_pats.strings);
        FREE(compression_folder_pats.strings);

        config->buf = mem;
        return 0;
}

void
destroy_capture_config(struct capture_config *config)
{
        FREE(config->exclusion_pats.strings);
        FREE(config->exclusion_exception_pats.strings);
        FREE(config->buf);
}

/*
 * Determine whether @path, or any ancestor directory of @path, matches any of
 * the patterns in @list.  Path separators in @path must be WIM_PATH_SEPARATOR.
 */
bool
match_pattern_list(const tchar *path, const struct string_set *list)
{
        for (size_t i = 0; i < list->num_strings; i++)
                if (match_path(path, list->strings[i], true))
                        return true;
        return false;
}

/*
 * Determine if a file should be excluded from capture.
 *
 * This function tests exclusions from both possible sources of exclusions:
 *
 *      (1) The capture configuration file
 *      (2) The user-provided progress function
 *
 * The capture implementation must have set params->capture_root_nchars to an
 * appropriate value.  Example for UNIX:  if the capture root directory is
 * "foobar/subdir", then all paths will be provided starting with
 * "foobar/subdir", so params->capture_root_nchars must be set to
 * strlen("foobar/subdir") so that the appropriate path can be matched against
 * the patterns in the exclusion list.
 *
 * Returns:
 *      < 0 if excluded
 *      = 0 if not excluded and no error
 *      > 0 (wimlib error code) if error
 */
int
try_exclude(const tchar *full_path, const struct capture_params *params)
{
        int ret;

        if (params->config) {
                const tchar *path = full_path + params->capture_root_nchars;
                if (match_pattern_list(path, &params->config->exclusion_pats) &&
                    !match_pattern_list(path, &params->config->exclusion_exception_pats))
                        return -1;
        }

        if (unlikely(params->add_flags & WIMLIB_ADD_FLAG_TEST_FILE_EXCLUSION)) {

                union wimlib_progress_info info;
                tchar *cookie;

                info.test_file_exclusion.path = full_path;
                info.test_file_exclusion.will_exclude = false;

                cookie = progress_get_win32_path(full_path);

                ret = call_progress(params->progfunc, WIMLIB_PROGRESS_MSG_TEST_FILE_EXCLUSION,
                                    &info, params->progctx);

                progress_put_win32_path(cookie);

                if (ret)
                        return ret;
                if (info.test_file_exclusion.will_exclude)
                        return -1;
        }

        return 0;
}

/*
 * Determine whether a directory entry of the specified name should be ignored.
 * This is a lower level function which runs prior to try_exclude().  It handles
 * the standard '.' and '..' entries, which show up in directory listings but
 * should not be archived.  It also checks for odd filenames that usually should
 * not exist but could cause problems if archiving them were to be attempted.
 */
bool
should_ignore_filename(const tchar *name, const int name_nchars)
{
        if (name_nchars <= 0) {
                WARNING("Ignoring empty filename");
                return true;
        }

        if (name[0] == T('.') &&
            (name_nchars == 1 || (name_nchars == 2 && name[1] == T('.'))))
                return true;

        for (int i = 0; i < name_nchars; i++) {
                if (name[i] == T('\0')) {
                        WARNING("Ignoring filename containing embedded null character");
                        return true;
                }
                if (name[i] == OS_PREFERRED_PATH_SEPARATOR) {
                        WARNING("Ignoring filename containing embedded path separator");
                        return true;
                }
        }

        return false;
}

/* Attach a newly scanned directory tree to its parent directory, with duplicate
 * handling.  */
void
attach_scanned_tree(struct wim_dentry *parent, struct wim_dentry *child,
                    struct blob_table *blob_table)
{
        struct wim_dentry *duplicate;

        if (child && (duplicate = dentry_add_child(parent, child))) {
                WARNING("Duplicate file path: \"%"TS"\".  Only capturing "
                        "the first version.", dentry_full_path(duplicate));
                free_dentry_tree(child, blob_table);
        }
}