path: root/afh.c

/* SPDX-License-Identifier: GPL-2.0 */

/** \file afh.c The audio format handler tool.
 *
 * This file contains the main function of para_afh(1), which is the only
 * program which calls \ref audio_format_handler::rewrite_tags() to change the
 * metadata of an audio file, for example the id3 tags of an mp3 file. Most of
 * the remaining functionality of para_afh(1) is shared with other programs
 * and is therefore implemented elsewhere, either in the command handlers
 * or in \ref afh_common.c.
 *
 * para_afh(1) does not employ the paraslash scheduler.
 */

/** \cond doxygen_ignore */

#include <lopsub.h>

#include "afh.lsg.h"
#include "para.h"
#include "string.h"
#include "fd.h"
#include "afh.h"
#include "error.h"

DEFINE_PARA_ERRLIST;

static struct lls_parse_result *lpr;

#define CMD_PTR (lls_cmd(0, afh_suite))
#define OPT_RESULT(_name) (lls_opt_result(LSG_AFH_PARA_AFH_OPT_ ## _name, lpr))
#define OPT_GIVEN(_name) (lls_opt_given(OPT_RESULT(_name)))
#define OPT_STRING_VAL(_name) (lls_string_val(0, OPT_RESULT(_name)))
#define OPT_UINT32_VAL(_name) (lls_uint32_val(0, OPT_RESULT(_name)))

static int loglevel;
INIT_STDERR_LOGGING(loglevel)

static inline bool tag_needs_update(bool given, const char *tag,
		const char *arg)
{
	return given && (!tag || strcmp(tag, arg) != 0);
}

/*
 * This is just a simple wrapper for the rename(2) system call which returns
 * a paraslash error code and prints an error message on failure.
 */
static int xrename(const char *oldpath, const char *newpath)
{
	int ret = rename(oldpath, newpath);

	if (ret >= 0)
		return 1;
	ret = -ERRNO_TO_PARA_ERROR(errno);
	PARA_ERROR_LOG("failed to rename %s -> %s\n", oldpath, newpath);
	return ret;
}

static int rewrite_tags(const char *name, int input_fd, void *map,
		size_t map_size, int audio_format_id, struct afh_info *afhi)
{
	struct taginfo *tags = &afhi->tags;
	bool modified = false;
	char *tmp_name;
	const char *arg;
	int output_fd = -1, ret;
	struct stat sb;

	arg = OPT_STRING_VAL(YEAR);
	if (tag_needs_update(OPT_GIVEN(YEAR), tags->year, arg)) {
		free(tags->year);
		tags->year = para_strdup(arg);
		modified = true;
	}
	arg = OPT_STRING_VAL(TITLE);
	if (tag_needs_update(OPT_GIVEN(TITLE), tags->title, arg)) {
		free(tags->title);
		tags->title = para_strdup(arg);
		modified = true;
	}
	arg = OPT_STRING_VAL(ARTIST);
	if (tag_needs_update(OPT_GIVEN(ARTIST), tags->artist, arg)) {
		free(tags->artist);
		tags->artist = para_strdup(arg);
		modified = true;
	}
	arg = OPT_STRING_VAL(ALBUM);
	if (tag_needs_update(OPT_GIVEN(ALBUM), tags->album, arg)) {
		free(tags->album);
		tags->album = para_strdup(arg);
		modified = true;
	}
	arg = OPT_STRING_VAL(COMMENT);
	if (tag_needs_update(OPT_GIVEN(COMMENT), tags->comment, arg)) {
		free(tags->comment);
		tags->comment = para_strdup(arg);
		modified = true;
	}
	if (!modified) {
		PARA_WARNING_LOG("no modifications necessary\n");
		return 0;
	}
	/*
	 * mkstmp() creates the temporary file with permissions 0600, but we
	 * like it to have the same permissions as the original file, so we
	 * have to get this information.
	 */
	if (fstat(input_fd, &sb) < 0) {
		ret = -ERRNO_TO_PARA_ERROR(errno);
		PARA_ERROR_LOG("failed to fstat fd %d (%s)\n", input_fd, name);
		return ret;
	}
	tmp_name = make_message("%s.XXXXXX", name);
	ret = mkstemp(tmp_name);
	if (ret < 0) {
		ret = -ERRNO_TO_PARA_ERROR(errno);
		PARA_ERROR_LOG("could not create temporary file\n");
		goto out;
	}
	output_fd = ret;
	if (fchmod(output_fd, sb.st_mode) < 0) {
		ret = -ERRNO_TO_PARA_ERROR(errno);
		PARA_ERROR_LOG("failed to fchmod fd %d (%s)\n", output_fd,
			tmp_name);
		goto out;
	}
	ret = afh_rewrite_tags(audio_format_id, map, map_size, tags, output_fd);
	if (ret < 0)
		goto out;
	if (OPT_GIVEN(BACKUP)) {
		char *backup_name = make_message("%s~", name);
		ret = xrename(name, backup_name);
		free(backup_name);
		if (ret < 0)
			goto out;
	}
	ret = xrename(tmp_name, name);
	if (ret < 0)
		goto out;
	if (OPT_GIVEN(PRESERVE)) {
		struct timespec times[2]; /* [0]: atime, [1]: mtime */
		times[0].tv_nsec = UTIME_OMIT;
		times[1] = sb.st_mtim;
		/*
		 * We might well have written a file of identical size. If we
		 * keep the mtime as well, we might fool backup applications
		 * like rsync which skip files whose size and mtime haven't
		 * changed. So we change the mtime slightly.
		 */
		times[1].tv_sec++;
		if (futimens(output_fd, times) < 0) {
			ret = -ERRNO_TO_PARA_ERROR(errno);
			goto out;
		}
	}
out:
	if (ret < 0 && output_fd >= 0)
		unlink(tmp_name); /* ignore errors */
	free(tmp_name);
	if (output_fd >= 0)
		close(output_fd);
	return ret;
}

static void print_info(int audio_format_num, struct afh_info *afhi)
{
	char *msg;

	afh_get_afhi_txt(audio_format_num, afhi, &msg);
	printf("%s", msg);
	free(msg);
}

static void print_chunk_table(struct afh_info *afhi, int audio_format_id,
		const void *map, size_t mapsize)
{
	int i, ret;
	void *ctx = NULL;

	for (i = 0; i < afhi->chunks_total; i++) {
		struct timeval tv;
		long unsigned from, to;
		const char *buf;
		uint32_t len;
		tv_scale(i, &afhi->chunk_tv, &tv);
		from = tv2ms(&tv);
		tv_scale(i + 1, &afhi->chunk_tv, &tv);
		to = tv2ms(&tv);
		ret = afh_get_chunk(i, afhi, audio_format_id, map, mapsize,
			&buf, &len, &ctx);
		if (ret < 0) {
			PARA_ERROR_LOG("fatal: chunk %d: %s\n", i,
				para_strerror(-ret));
			return;
		}
		if (!OPT_GIVEN(PARSER_FRIENDLY))
			printf("%d [%lu.%03lu - %lu.%03lu] ", i, from / 1000,
				from % 1000, to / 1000, to % 1000);
		printf("%td - %td", buf - (const char *)map,
			buf + len - (const char *)map);
		if (!OPT_GIVEN(PARSER_FRIENDLY))
			printf(" (%u)", len);
		printf("\n");
	}
	afh_close(ctx, audio_format_id);
}

static void handle_help_flags(void)
{
	char *help;

	if (OPT_GIVEN(DETAILED_HELP))
		help = lls_long_help(CMD_PTR);
	else if (OPT_GIVEN(HELP) || lls_num_inputs(lpr) == 0)
		help = lls_short_help(CMD_PTR);
	else
		return;
	printf("%s", help);
	free(help);
	printf("Supported audio formats\n  %s\n", AUDIO_FORMAT_HANDLERS);
	exit(EXIT_SUCCESS);
}

/** \endcond
 *
 * List audio format handler information or modify tags.
 *
 * This iterates over all given paths. At each iteration, \ref mmap_full_file()
 * is called to map the file into memory, followed by \ref compute_afhi()
 * to detect the audio format and to initialize an \ref afh_info structure.
 *
 * The default mode calls \ref afh_get_afhi_txt() to pretty-print the
 * thusly obtained audio format handler information. In modify mode, \ref
 * afh_rewrite_tags() is called instead to modify the tags.
 *
 * \param argc Options are defined in the afh lopsub suite.
 * \param argv The afh suite defines no subcommands.
 *
 * \return EXIT_FAILURE or EXIT_SUCCESS.
 */
int main(int argc, char **argv)
{
	int i, ret = 0, audio_format_num, fd;
	void *map;
	size_t audio_file_size;
	struct afh_info afhi;
	char *errctx;

	ret = lls(lls_parse(argc, argv, CMD_PTR, &lpr, &errctx));
	if (ret < 0)
		goto out;
	loglevel = OPT_UINT32_VAL(LOGLEVEL);
	version_handle_flag("afh", OPT_GIVEN(VERSION));
	handle_help_flags();
	for (i = 0; i < lls_num_inputs(lpr); i++) {
		int ret2;
		const char *path = lls_input(i, lpr);
		ret = mmap_full_file(path, O_RDONLY, &map, &audio_file_size,
			&fd);
		if (ret < 0) {
			PARA_ERROR_LOG("failed to mmap \"%s\"\n", path);
			goto out;
		}
		ret = compute_afhi(path, map, audio_file_size, &afhi);
		if (ret >= 0) {
			audio_format_num = ret;
			if (OPT_GIVEN(MODIFY)) {
				ret = rewrite_tags(path, fd, map,
					audio_file_size, audio_format_num, &afhi);
			} else {
				printf("File %d: %s\n", i + 1, path);
				print_info(audio_format_num, &afhi);
				if (OPT_GIVEN(CHUNK_TABLE))
					print_chunk_table(&afhi, audio_format_num,
						map, audio_file_size);
			}
			clear_afhi(&afhi);
		}
		close(fd);
		ret2 = para_munmap(map, audio_file_size);
		if (ret2 < 0 && ret >= 0)
			ret = ret2;
		if (ret < 0)
			break;
	}
out:
	if (errctx)
		PARA_ERROR_LOG("%s\n", errctx);
	if (ret < 0)
		PARA_EMERG_LOG("%s\n", para_strerror(-ret));
	lls_free_parse_result(lpr, CMD_PTR);
	return ret < 0? EXIT_FAILURE : EXIT_SUCCESS;
}