/*
 * Guillaume Cottenceau (gc@mandrakesoft.com)
 *
 * Copyright 2000 MandrakeSoft
 *
 * This software may be freely redistributed under the terms of the GNU
 * public license.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

/*
 * Portions from Erik Troan (ewt@redhat.com)
 *
 * Copyright 1996 Red Hat Software 
 *
 */

#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <glob.h>
#include "stage1.h"
#include "frontend.h"
#include "modules.h"
#include "probing.h"
#include "log.h"
#include "mount.h"
#include "lomount.h"
#include "automatic.h"

#include "disk.h"

extern char version[];

struct partition_detection_anchor {
	off_t offset;
	const char * anchor;
};

static int seek_and_compare(int fd, struct partition_detection_anchor anch)
{
	char buf[500];
	int count;
	if (lseek(fd, anch.offset, SEEK_SET) == (off_t)-1) {
		log_perror("seek failed");
		return -1;
	}
	count = read(fd, buf, strlen(anch.anchor));
	if (count != strlen(anch.anchor)) {
		log_perror("read failed");
		return -1;
	}
	buf[count] = '\0';
	if (strcmp(anch.anchor, buf))
		return 1;
	return 0;
}

static const char * detect_partition_type(char * dev)
{
	struct partition_detection_info {
		const char * name;
		struct partition_detection_anchor anchor0;
		struct partition_detection_anchor anchor1;
		struct partition_detection_anchor anchor2;
	} partitions_signatures[] = { 
		{ "Linux Swap", { 4086, "SWAP-SPACE" }, { 0, NULL }, { 0, NULL } },
		{ "Linux Swap", { 4086, "SWAPSPACE2" }, { 0, NULL }, { 0, NULL } },
		{ "Ext2", { 0x438, "\x53\xEF" }, { 0, NULL }, { 0, NULL } },
		{ "ReiserFS", { 0x10034, "ReIsErFs" }, { 0, NULL }, { 0, NULL } },
		{ "ReiserFS", { 0x10034, "ReIsEr2Fs" }, { 0, NULL }, { 0, NULL } },
		{ "XFS", { 0, "XFSB" }, { 0x200, "XAGF" }, { 0x400, "XAGI" } },
		{ "JFS", { 0x8000, "JFS1" }, { 0, NULL }, { 0, NULL } },
		{ "NTFS", { 0x1FE, "\x55\xAA" }, { 0x3, "NTFS" }, { 0, NULL } },
		{ "FAT32", { 0x1FE, "\x55\xAA" }, { 0x52, "FAT32" }, { 0, NULL } },
		{ "FAT", { 0x1FE, "\x55\xAA" }, { 0x36, "FAT" }, { 0, NULL } },
		{ "Linux LVM", { 0, "HM\1\0" }, { 0, NULL }, { 0, NULL } }
	};
	int partitions_signatures_nb = sizeof(partitions_signatures) / sizeof(struct partition_detection_info);
	int i;
	int fd;

	char device_fullname[50];
	strcpy(device_fullname, "/dev/");
	strcat(device_fullname, dev);

	if (ensure_dev_exists(device_fullname))
		return NULL;
	log_message("guessing type of %s", device_fullname);

	if ((fd = open(device_fullname, O_RDONLY, 0)) < 0) {
		log_perror("open");
		return NULL;
	}
	
	for (i=0; i<partitions_signatures_nb; i++) {
		int results = seek_and_compare(fd, partitions_signatures[i].anchor0);
		if (results == -1)
			goto detect_partition_type_end;
		if (results == 1)
			continue;
		if (!partitions_signatures[i].anchor1.anchor)
			goto detect_partition_found_it;

		results = seek_and_compare(fd, partitions_signatures[i].anchor1);
		if (results == -1)
			goto detect_partition_type_end;
		if (results == 1)
			continue;
		if (!partitions_signatures[i].anchor2.anchor)
			goto detect_partition_found_it;

		results = seek_and_compare(fd, partitions_signatures[i].anchor2);
		if (results == -1)
			goto detect_partition_type_end;
		if (results == 1)
			continue;

	detect_partition_found_it:
		return partitions_signatures[i].name;
	}

 detect_partition_type_end:
	close(fd);
	return NULL;
}

static char * disk_extract_list_directory(char * direct)
{
	char ** full = list_directory(direct);
	char tmp[2000] = "";
	int i;
	for (i=0; i<5 ; i++) {
		if (!full || !*full)
			break;
		strcat(tmp, *full);
		strcat(tmp, "\n");
		full++;
	}
	return strdup(tmp);
}

static enum return_type try_with_partition(char *choice);

static enum return_type try_with_uuidlabel()
{
	char device_fullname[128];
	char device_pattern[128];
	glob_t globbuf;
	char devname[50];
	struct stat statbuf;
	int len;
	
	strcpy(device_fullname, "/dev/disk/by-uuid/");
	strcat(device_fullname, get_auto_value("uuid"));
	if (stat(device_fullname, &statbuf) == 0 && S_ISBLK(statbuf.st_mode) &&
		(len = readlink(device_fullname, devname, sizeof(devname))) != -1) {
		devname[len] = 0;
		return try_with_partition(strrchr(devname, '/') + 1);
	}

	strcpy(device_pattern, "/dev/disk/by-label/");
	strcat(device_pattern, get_auto_value("label"));
	/* Allow to use glob match in label, like automatic=method:disk,label:ALT* */
	if( glob(device_pattern, 0, NULL, &globbuf) == 0 ) {
		strcpy(device_fullname, globbuf.gl_pathv[0]);
		if (stat(device_fullname, &statbuf) == 0 && S_ISBLK(statbuf.st_mode) &&
				(len = readlink(device_fullname, devname, sizeof(devname))) != -1) {
			devname[len] = 0;
			globfree(&globbuf);
			return try_with_partition(strrchr(devname, '/') + 1);
		}
	}
	globfree(&globbuf);
	return RETURN_ERROR;
}

static enum return_type try_with_device(char *dev_name)
{
	int major, minor, blocks;
	char name[100];

	char buf[512];
	FILE * f;
	char * parts[50];
	char * parts_comments[50];
	int i = 0;
	enum return_type results;
	char * choice;

	if (!(f = fopen("/proc/partitions", "rb")) || !fgets(buf, sizeof(buf), f) || !fgets(buf, sizeof(buf), f)) {
		log_perror(dev_name);
		stg1_error_message("Could not read partitions information.");
		return RETURN_ERROR;
	}

	while (fgets(buf, sizeof(buf), f)) {
		memset(name, 0, sizeof(name));
		sscanf(buf, " %d %d %d %s", &major, &minor, &blocks, name);
		if ((strstr(name, dev_name) == name) && (blocks > 1) && (name[strlen(dev_name)] != '\0')) {
			const char * partition_type = detect_partition_type(name);
			parts[i] = strdup(name);
			parts_comments[i] = (char *) malloc(sizeof(char) * 100);
			sprintf(parts_comments[i], "size: %d Mbytes", blocks >> 10);
			if (partition_type) {
				strcat(parts_comments[i], ", type: ");
				strcat(parts_comments[i], partition_type);
			}
			i++;
		}
	}
	parts[i] = NULL;
	fclose(f);

	if (parts[0] == NULL) {
		stg1_error_message("No partitions found.");
		return RETURN_ERROR;
	}

	snprintf(buf, sizeof(buf), "Please choose the partition where is copied the %s Distribution.", version);
	results = ask_from_list_comments_auto(buf, parts, parts_comments, &choice, "partition", parts);
	if (results != RETURN_OK)
		return results;

	if (try_with_partition(choice) != RETURN_OK)
		return try_with_device(dev_name);
	else
		return RETURN_OK;
}

static enum return_type try_with_partition(char *choice)
{
	char * questions_location[] = { "Directory or ISO image", NULL };
	char * questions_location_auto[] = { "directory", NULL };
	static char ** answers_location = NULL;

	char device_fullname[50];
	char location_full[500];
	char buf[512];

	struct stat statbuf;
	int iso = 0;

	strcpy(device_fullname, "/dev/");
	strcat(device_fullname, choice);

	if (my_mount(device_fullname, IMAGE_LOCATION, "ext2", 0) == -1 &&
	    my_mount(device_fullname, IMAGE_LOCATION, "ext3", 0) == -1 &&
	    my_mount(device_fullname, IMAGE_LOCATION, "vfat", 0) == -1 &&
	    my_mount(device_fullname, IMAGE_LOCATION, "ntfs", 0) == -1 &&
	    my_mount(device_fullname, IMAGE_LOCATION, "iso9660", 0) == -1 &&
	    my_mount(device_fullname, IMAGE_LOCATION, "reiserfs", 0) == -1) {
		stg1_error_message("I can't find a valid filesystem (tried: ext2, ext3, vfat, ntfs, iso9660, reiserfs).");
		return RETURN_ERROR;
	}

	snprintf(buf, sizeof(buf), "Please enter the directory (or ISO image file) containing the %s Distribution.", version);
	if (ask_from_entries_auto(buf, questions_location, &answers_location, 24, questions_location_auto, NULL) != RETURN_OK) {
		umount(IMAGE_LOCATION);
		return RETURN_ERROR;
	}

	strcpy(location_full, IMAGE_LOCATION);
	strcat(location_full, "/");
	strcat(location_full, answers_location[0]);

	if (access(location_full, R_OK)) {
		stg1_error_message("Directory or ISO image file could not be found on partition.\n"
			      "Here's a short extract of the files in the root of the partition:\n"
			      "%s", disk_extract_list_directory(IMAGE_LOCATION));
		umount(IMAGE_LOCATION);
		return RETURN_ERROR;
	}

	if (!stat(location_full, &statbuf) && !S_ISDIR(statbuf.st_mode)) {
		log_message("%s exists and is not a directory, assuming this is an ISO image", location_full);
		if (lomount(location_full, IMAGE_LOCATION)) {
			stg1_error_message("Could not mount file %s as an ISO image of the %s Distribution.", answers_location[0], version);
			umount(IMAGE_LOCATION);
			return RETURN_ERROR;
		}
		iso = 1;
		add_to_env("PIGGYBACK", "1");
	}

	if (access(get_ramdisk_path(iso ? NULL : location_full), R_OK)) {
		stg1_error_message("I can't find the %s Distribution in the specified directory. "
						   "Here's a short extract of the files in the directory:\n"
						   "%s", version, disk_extract_list_directory(IMAGE_LOCATION));
			loumount();
			umount(IMAGE_LOCATION);
			return RETURN_ERROR;
	}

	log_message("found the %s Installation, good news!", version);

	if (!IS_LOWMEM && ramdisk_possible()) {
		if (load_ramdisk(iso ? NULL : location_full) != RETURN_OK) {
			stg1_error_message("Could not load program into memory.");
			loumount();
			umount(IMAGE_LOCATION);
			return RETURN_ERROR;
		}
	} else {
		do_losetup(LIVE_DEVICE, get_ramdisk_path(iso ? NULL : location_full));
		my_mount(LIVE_DEVICE, STAGE2_LOCATION, (IS_LIVE) ? LIVEFS : STAGE2FS, 0);
	}
	
	add_to_env("DEVICE", choice);
	add_to_env("METHOD", strdup("disk"));
	add_to_env("PREFIX", answers_location[0]);

	return RETURN_OK;
}

enum return_type disk_prepare(void)
{
	char ** medias, ** ptr, ** medias_models;
	char * choice;
	char msg[256];
	int i, count = 0;
	enum return_type results;

	get_medias(DISK, &medias, &medias_models);

	ptr = medias;
	while (ptr && *ptr) {
		count++;
		ptr++;
	}

	if (count == 0) {
		stg1_error_message("No DISK drive found.");
		return RETURN_BACK;
	}

	if (try_with_uuidlabel() == RETURN_OK)
		return RETURN_OK;

	if (count == 1) {
		results = try_with_device(*medias);
		return (results == RETURN_OK) ? RETURN_OK : RETURN_BACK;
	}

	snprintf(msg, sizeof(msg), "Please choose the DISK drive on which you copied the %s Distribution.", version);
	results = ask_from_list_comments_auto(msg, medias, medias_models, &choice, "disk", medias);

	if (results != RETURN_OK)
		return results;

	results = try_with_device(choice);
	if (results == RETURN_OK)
		return RETURN_OK;
	i = ask_insmod();
	if (i == RETURN_BACK)
		return RETURN_BACK;
	return disk_prepare();
}