//
//  pkgutils
// 
//  Copyright (c) 2000-2004 Per Liden
// 
//  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
//  the Free Software Foundation; either version 2 of the License, or
//  (at your option) any later version.
//
//  This program 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 General Public License for more details.
//
//  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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 
//  USA.
//

#include "pkgutil.h"
#include <iostream>
#include <fstream>
#include <iterator>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cerrno>
#include <csignal>
#include <ext/stdio_filebuf.h>
#include <pwd.h>
#include <grp.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/file.h>
#include <unistd.h>
#include <fcntl.h>
#include <zlib.h>
#include <libgen.h>
#include <libtar.h>

using __gnu_cxx::stdio_filebuf;

static tartype_t gztype = {
	(openfunc_t)unistd_gzopen,
	(closefunc_t)gzclose,
	(readfunc_t)gzread,
	(writefunc_t)gzwrite
};

pkgutil::pkgutil(const string& name)
	: utilname(name)
{
	// Ignore signals
	struct sigaction sa;
	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = SIG_IGN;
	sigaction(SIGHUP, &sa, 0);
	sigaction(SIGINT, &sa, 0);
	sigaction(SIGQUIT, &sa, 0);
	sigaction(SIGTERM, &sa, 0);
}

void pkgutil::db_open(const string& path)
{
	// Read database
	root = trim_filename(path + "/");
	const string filename = root + PKG_DB;

	int fd = open(filename.c_str(), O_RDONLY);
	if (fd == -1)
		throw runtime_error_with_errno("could not open " + filename);

//	stdio_filebuf<char> filebuf(fd, ios::in, true, getpagesize());
	stdio_filebuf<char> filebuf(fd, ios::in, true);
	istream in(&filebuf);
	if (!in)
		throw runtime_error_with_errno("could not read " + filename);

	while (!in.eof()) {
		// Read record
		string name;
		pkginfo_t info;
		getline(in, name);
		getline(in, info.version);
		for (;;) {
			string file;
			getline(in, file);
         
			if (file.empty())
				break; // End of record
         
			info.files.insert(info.files.end(), file);
		}
		if (!info.files.empty())
			packages[name] = info;
	}

#ifndef NDEBUG
	cerr << packages.size() << " packages found in database" << endl;
#endif
}

void pkgutil::db_commit()
{
	const string dbfilename = root + PKG_DB;
	const string dbfilename_new = dbfilename + ".incomplete_transaction";
	const string dbfilename_bak = dbfilename + ".backup";

	// Remove failed transaction (if it exists)
	if (unlink(dbfilename_new.c_str()) == -1 && errno != ENOENT)
		throw runtime_error_with_errno("could not remove " + dbfilename_new);

	// Write new database
	int fd_new = creat(dbfilename_new.c_str(), 0444);
	if (fd_new == -1)
		throw runtime_error_with_errno("could not create " + dbfilename_new);

	stdio_filebuf<char> filebuf_new(fd_new, ios::out, true);
	ostream db_new(&filebuf_new);
	for (packages_t::const_iterator i = packages.begin(); i != packages.end(); ++i) {
		if (!i->second.files.empty()) {
			db_new << i->first << "\n";
			db_new << i->second.version << "\n";
			copy(i->second.files.begin(), i->second.files.end(), ostream_iterator<string>(db_new, "\n"));
			db_new << "\n";
		}
	}

	db_new.flush();

	// Make sure the new database was successfully written
	if (!db_new)
		throw runtime_error("could not write " + dbfilename_new);

	// Synchronize file to disk
	if (fsync(fd_new) == -1)
		throw runtime_error_with_errno("could not synchronize " + dbfilename_new);

	// Relink database backup
	if (unlink(dbfilename_bak.c_str()) == -1 && errno != ENOENT)
		throw runtime_error_with_errno("could not remove " + dbfilename_bak);	
	if (link(dbfilename.c_str(), dbfilename_bak.c_str()) == -1)
		throw runtime_error_with_errno("could not create " + dbfilename_bak);

	// Move new database into place
	if (rename(dbfilename_new.c_str(), dbfilename.c_str()) == -1)
		throw runtime_error_with_errno("could not rename " + dbfilename_new + " to " + dbfilename);

#ifndef NDEBUG
	cerr << packages.size() << " packages written to database" << endl;
#endif
}

void pkgutil::db_add_pkg(const string& name, const pkginfo_t& info)
{
	packages[name] = info;
}

bool pkgutil::db_find_pkg(const string& name)
{
	return (packages.find(name) != packages.end());
}

void pkgutil::db_rm_pkg(const string& name)
{
	set<string> files = packages[name].files;
	packages.erase(name);

#ifndef NDEBUG
	cerr << "Removing package phase 1 (all files in package):" << endl;
	copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
	cerr << endl;
#endif

	// Don't delete files that still have references
	for (packages_t::const_iterator i = packages.begin(); i != packages.end(); ++i)
		for (set<string>::const_iterator j = i->second.files.begin(); j != i->second.files.end(); ++j)
			files.erase(*j);

#ifndef NDEBUG
	cerr << "Removing package phase 2 (files that still have references excluded):" << endl;
	copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
	cerr << endl;
#endif

	// Delete the files
	for (set<string>::const_reverse_iterator i = files.rbegin(); i != files.rend(); ++i) {
		const string filename = root + *i;
		if (file_exists(filename) && remove(filename.c_str()) == -1) {
			const char* msg = strerror(errno);
			cerr << utilname << ": could not remove " << filename << ": " << msg << endl;
		}
	}
}

void pkgutil::db_rm_pkg(const string& name, const set<string>& keep_list)
{
	set<string> files = packages[name].files;
	packages.erase(name);

#ifndef NDEBUG
	cerr << "Removing package phase 1 (all files in package):" << endl;
	copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
	cerr << endl;
#endif

	// Don't delete files found in the keep list
	for (set<string>::const_iterator i = keep_list.begin(); i != keep_list.end(); ++i)
		files.erase(*i);

#ifndef NDEBUG
	cerr << "Removing package phase 2 (files that is in the keep list excluded):" << endl;
	copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
	cerr << endl;
#endif

	// Don't delete files that still have references
	for (packages_t::const_iterator i = packages.begin(); i != packages.end(); ++i)
		for (set<string>::const_iterator j = i->second.files.begin(); j != i->second.files.end(); ++j)
			files.erase(*j);

#ifndef NDEBUG
	cerr << "Removing package phase 3 (files that still have references excluded):" << endl;
	copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
	cerr << endl;
#endif

	// Delete the files
	for (set<string>::const_reverse_iterator i = files.rbegin(); i != files.rend(); ++i) {
		const string filename = root + *i;
		if (file_exists(filename) && remove(filename.c_str()) == -1) {
			if (errno == ENOTEMPTY)
				continue;
			const char* msg = strerror(errno);
			cerr << utilname << ": could not remove " << filename << ": " << msg << endl;
		}
	}
}

void pkgutil::db_rm_files(set<string> files, const set<string>& keep_list)
{
	// Remove all references
	for (packages_t::iterator i = packages.begin(); i != packages.end(); ++i)
		for (set<string>::const_iterator j = files.begin(); j != files.end(); ++j)
			i->second.files.erase(*j);
   
#ifndef NDEBUG
	cerr << "Removing files:" << endl;
	copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
	cerr << endl;
#endif

	// Don't delete files found in the keep list
	for (set<string>::const_iterator i = keep_list.begin(); i != keep_list.end(); ++i)
		files.erase(*i);

	// Delete the files
	for (set<string>::const_reverse_iterator i = files.rbegin(); i != files.rend(); ++i) {
		const string filename = root + *i;
		if (file_exists(filename) && remove(filename.c_str()) == -1) {
			if (errno == ENOTEMPTY)
				continue;
			const char* msg = strerror(errno);
			cerr << utilname << ": could not remove " << filename << ": " << msg << endl;
		}
	}
}

set<string> pkgutil::db_find_conflicts(const string& name, const pkginfo_t& info)
{
	set<string> files;
   
	// Find conflicting files in database
	for (packages_t::const_iterator i = packages.begin(); i != packages.end(); ++i) {
		if (i->first != name) {
			set_intersection(info.files.begin(), info.files.end(),
					 i->second.files.begin(), i->second.files.end(),
					 inserter(files, files.end()));
		}
	}
	
#ifndef NDEBUG
	cerr << "Conflicts phase 1 (conflicts in database):" << endl;
	copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
	cerr << endl;
#endif

	// Find conflicting files in filesystem
	for (set<string>::iterator i = info.files.begin(); i != info.files.end(); ++i) {
		const string filename = root + *i;
		if (file_exists(filename) && files.find(*i) == files.end())
			files.insert(files.end(), *i);
	}

#ifndef NDEBUG
	cerr << "Conflicts phase 2 (conflicts in filesystem added):" << endl;
	copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
	cerr << endl;
#endif

	// Exclude directories
	set<string> tmp = files;
	for (set<string>::const_iterator i = tmp.begin(); i != tmp.end(); ++i) {
		if ((*i)[i->length() - 1] == '/')
			files.erase(*i);
	}

#ifndef NDEBUG
	cerr << "Conflicts phase 3 (directories excluded):" << endl;
	copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
	cerr << endl;
#endif

	// If this is an upgrade, remove files already owned by this package
	if (packages.find(name) != packages.end()) {
		for (set<string>::const_iterator i = packages[name].files.begin(); i != packages[name].files.end(); ++i)
			files.erase(*i);

#ifndef NDEBUG
		cerr << "Conflicts phase 4 (files already owned by this package excluded):" << endl;
		copy(files.begin(), files.end(), ostream_iterator<string>(cerr, "\n"));
		cerr << endl;
#endif
	}

	return files;
}

pair<string, pkgutil::pkginfo_t> pkgutil::pkg_open(const string& filename) const
{
	pair<string, pkginfo_t> result;
	unsigned int i;
	TAR* t;

	// Extract name and version from filename
	string basename(filename, filename.rfind('/') + 1);
	string name(basename, 0, basename.find(VERSION_DELIM));
	string version(basename, 0, basename.rfind(PKG_EXT));
	version.erase(0, version.find(VERSION_DELIM) == string::npos ? string::npos : version.find(VERSION_DELIM) + 1);
   
	if (name.empty() || version.empty())
		throw runtime_error("could not determine name and/or version of " + basename + ": Invalid package name");

	result.first = name;
	result.second.version = version;

	if (tar_open(&t, const_cast<char*>(filename.c_str()), &gztype, O_RDONLY, 0, TAR_GNU) == -1)
		throw runtime_error_with_errno("could not open " + filename);

	for (i = 0; !th_read(t); ++i) {
		result.second.files.insert(result.second.files.end(), th_get_pathname(t));
		if (TH_ISREG(t) && tar_skip_regfile(t))
			throw runtime_error_with_errno("could not read " + filename);
	}
   
	if (i == 0) {
		if (errno == 0)
			throw runtime_error("empty package");
		else
			throw runtime_error("could not read " + filename);
	}

	tar_close(t);

	return result;
}

void pkgutil::pkg_install(const string& filename, const set<string>& keep_list) const
{
	TAR* t;
	unsigned int i;

	if (tar_open(&t, const_cast<char*>(filename.c_str()), &gztype, O_RDONLY, 0, TAR_GNU) == -1)
		throw runtime_error_with_errno("could not open " + filename);

	for (i = 0; !th_read(t); ++i) {
		string archive_filename = th_get_pathname(t);
		string reject_dir = trim_filename(root + string("/") + string(PKG_REJECTED));
		string original_filename = trim_filename(root + string("/") + archive_filename);
		string real_filename = original_filename;

		// Check if file should be rejected
		if (file_exists(real_filename) && keep_list.find(archive_filename) != keep_list.end())
			real_filename = trim_filename(reject_dir + string("/") + archive_filename);

		// Extract file
		if (tar_extract_file(t, const_cast<char*>(real_filename.c_str()))) {
			// If a file fails to install we just print an error message and
			// continue trying to install the rest of the package.
			const char* msg = strerror(errno);
			cerr << utilname << ": could not install " + archive_filename << ": " << msg << endl;
			continue;
		}

		// Check rejected file
		if (real_filename != original_filename) {
			bool remove_file = false;

			// Directory
			if (TH_ISDIR(t))
				remove_file = permissions_equal(real_filename, original_filename);
			
			// Regular file
			else if (TH_ISREG(t))
				remove_file = file_empty(real_filename) || file_equal(real_filename, original_filename);

			// Remove rejected file or signal about its existence
			if (remove_file)
				file_remove(reject_dir, real_filename);
			else
				cout << utilname << ": rejecting " << archive_filename << ", keeping existing version" << endl;
		}
	}

	if (i == 0) {
		if (errno == 0)
			throw runtime_error("empty package");
		else
			throw runtime_error("could not read " + filename);
	}

	tar_close(t);
}

void pkgutil::ldconfig() const
{
	// Only execute ldconfig if /etc/ld.so.conf exists
	if (file_exists(root + LDCONFIG_CONF)) {
		pid_t pid = fork();

		if (pid == -1)
			throw runtime_error_with_errno("fork() failed");

		if (pid == 0) {
			execl(LDCONFIG, LDCONFIG, "-r", root.c_str(), 0);
			const char* msg = strerror(errno);
			cerr << utilname << ": could not execute " << LDCONFIG << ": " << msg << endl;
			exit(EXIT_FAILURE);
		} else {
			if (waitpid(pid, 0, 0) == -1)
				throw runtime_error_with_errno("waitpid() failed");
		}
	}
}

void pkgutil::pkg_footprint(string& filename) const
{
        unsigned int i;
        TAR* t;

        if (tar_open(&t, const_cast<char*>(filename.c_str()), &gztype, O_RDONLY, 0, TAR_GNU) == -1)
                throw runtime_error_with_errno("could not open " + filename);

        for (i = 0; !th_read(t); ++i) {
		// Access permissions
		if (TH_ISSYM(t)) {
			// Access permissions on symlinks differ among filesystems, e.g. XFS and ext2 have different.
			// To avoid getting different footprints we always use "lrwxrwxrwx".
			cout << "lrwxrwxrwx";
		} else {
			cout << mtos(th_get_mode(t));
		}

		cout << '\t';

		// User
		uid_t uid = th_get_uid(t);
		struct passwd* pw = getpwuid(uid);
		if (pw)
			cout << pw->pw_name;
		else
			cout << uid;

		cout << '/';

		// Group
		gid_t gid = th_get_gid(t);
		struct group* gr = getgrgid(gid);
		if (gr)
			cout << gr->gr_name;
		else
			cout << gid;

		// Filename
		cout << '\t' << th_get_pathname(t);

		// Special cases
		if (TH_ISSYM(t)) {
			// Symlink
			cout << " -> " << (((t->options & TAR_GNU) && t->th_buf.gnu_longlink) ? t->th_buf.gnu_longlink : t->th_buf.linkname);
		} else if (TH_ISCHR(t) || TH_ISBLK(t)) {
			// Device
			cout << " (" << th_get_devmajor(t) << ", " << th_get_devminor(t) << ")";
		} else if (TH_ISREG(t) && !th_get_size(t)) {
			// Empty regular file
			cout << " (EMPTY)";
		}

		cout << '\n';
		
                if (TH_ISREG(t) && tar_skip_regfile(t))
                        throw runtime_error_with_errno("could not read " + filename);
        }
   
        if (i == 0) {
                if (errno == 0)
                        throw runtime_error("empty package");
                else
                        throw runtime_error("could not read " + filename);
        }

        tar_close(t);
}

void pkgutil::print_version() const
{
	cout << utilname << " (pkgutils) " << VERSION << endl;
}

db_lock::db_lock(const string& root, bool exclusive)
	: dir(0)
{
	const string dirname = trim_filename(root + string("/") + PKG_DIR);

	if (!(dir = opendir(dirname.c_str())))
		throw runtime_error_with_errno("could not read directory " + dirname);

	if (flock(dirfd(dir), (exclusive ? LOCK_EX : LOCK_SH) | LOCK_NB) == -1) {
		if (errno == EWOULDBLOCK)
			throw runtime_error("package database is currently locked by another process");
		else
			throw runtime_error_with_errno("could not lock directory " + dirname);
	}
}

db_lock::~db_lock()
{
	if (dir) {
		flock(dirfd(dir), LOCK_UN);
		closedir(dir);
	}
}

void assert_argument(char** argv, int argc, int index)
{
	if (argc - 1 < index + 1)
		throw runtime_error("option " + string(argv[index]) + " requires an argument");
}

string itos(unsigned int value)
{
	static char buf[20];
	sprintf(buf, "%u", value);
	return buf;
}

string mtos(mode_t mode)
{
	string s;

	// File type
	switch (mode & S_IFMT) {
        case S_IFREG:  s += '-'; break; // Regular
        case S_IFDIR:  s += 'd'; break; // Directory
        case S_IFLNK:  s += 'l'; break; // Symbolic link
        case S_IFCHR:  s += 'c'; break; // Character special
        case S_IFBLK:  s += 'b'; break; // Block special
        case S_IFSOCK: s += 's'; break; // Socket
        case S_IFIFO:  s += 'p'; break; // Fifo
        default:       s += '?'; break; // Unknown
        }

	// User permissions
        s += (mode & S_IRUSR) ? 'r' : '-';
        s += (mode & S_IWUSR) ? 'w' : '-';
        switch (mode & (S_IXUSR | S_ISUID)) {
        case S_IXUSR:           s += 'x'; break;
        case S_ISUID:           s += 'S'; break;
        case S_IXUSR | S_ISUID: s += 's'; break;
        default:                s += '-'; break;
        }

        // Group permissions
	s += (mode & S_IRGRP) ? 'r' : '-';
        s += (mode & S_IWGRP) ? 'w' : '-';
        switch (mode & (S_IXGRP | S_ISGID)) {
        case S_IXGRP:           s += 'x'; break;
        case S_ISGID:           s += 'S'; break;
	case S_IXGRP | S_ISGID: s += 's'; break;
        default:                s += '-'; break;
        }

        // Other permissions
        s += (mode & S_IROTH) ? 'r' : '-';
        s += (mode & S_IWOTH) ? 'w' : '-';
        switch (mode & (S_IXOTH | S_ISVTX)) {
        case S_IXOTH:           s += 'x'; break;
        case S_ISVTX:           s += 'T'; break;
        case S_IXOTH | S_ISVTX: s += 't'; break;
        default:                s += '-'; break;
        }

	return s;
}

int unistd_gzopen(char* pathname, int flags, mode_t mode)
{
	char* gz_mode;
   
	switch (flags & O_ACCMODE) {
	case O_WRONLY:
		gz_mode = "w";
		break;

	case O_RDONLY:
		gz_mode = "r";
		break;

	case O_RDWR:
	default:
		errno = EINVAL;
		return -1;
	}

	int fd;
	gzFile gz_file;

	if ((fd = open(pathname, flags, mode)) == -1)
		return -1;
   
	if ((flags & O_CREAT) && fchmod(fd, mode))
		return -1;
   
	if (!(gz_file = gzdopen(fd, gz_mode))) {
		errno = ENOMEM;
		return -1;
	}
   
	return (int)gz_file;
}

string trim_filename(const string& filename)
{
	string search("//");
	string result = filename;

	for (string::size_type pos = result.find(search); pos != string::npos; pos = result.find(search))
		result.replace(pos, search.size(), "/");

	return result;
}

bool file_exists(const string& filename)
{
	struct stat buf;
	return !lstat(filename.c_str(), &buf);
}

bool file_empty(const string& filename)
{
	struct stat buf;
	return (!lstat(filename.c_str(), &buf) && !buf.st_size);
}

bool file_equal(const string& file1, const string& file2)
{
	ifstream f1(file1.c_str());
	ifstream f2(file2.c_str());
	
	if (!f1 || !f2)
		return false;

	while (!f1.eof()) {
		char buf1[4096];
		char buf2[4096];
		f1.read(buf1, 4096);
		f2.read(buf2, 4096);
		if (f1.gcount() != f2.gcount() ||
		    memcmp(buf1, buf2, f1.gcount()) ||
		    f1.eof() != f2.eof())
			return false;
	}

	return true;
}

bool permissions_equal(const string& file1, const string& file2)
{
	struct stat buf1;
	struct stat buf2;

	if (lstat(file1.c_str(), &buf1) == -1)
		return false;

	if (lstat(file2.c_str(), &buf2) == -1)
		return false;
	
	return buf1.st_mode == buf2.st_mode;
}

void file_remove(const string& basedir, const string& filename)
{
	if (filename != basedir && !remove(filename.c_str())) {
		char* path = strdup(filename.c_str());
		file_remove(basedir, dirname(path));
		free(path);
	}
}