/*-
 * Copyright (c) 2012 Baptiste Daroussin <bapt@FreeBSD.org>
 * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/elf_common.h>
#include <sys/endian.h>
#include <sys/wait.h>

#include <archive.h>
#include <archive_entry.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fetch.h>
#include <gelf.h>
#include <paths.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "elf_tables.h"

#define _LOCALBASE "/usr/local"
#define _PKGS_URL "http://pkgbeta.FreeBSD.org"

static const char *
elf_corres_to_string(struct _elf_corres *m, int e)
{
	int i;

	for (i = 0; m[i].string != NULL; i++)
		if (m[i].elf_nb == e)
			return (m[i].string);

	return ("unknown");
}

static int
pkg_get_myabi(char *dest, size_t sz)
{
	Elf *elf;
	Elf_Data *data;
	Elf_Note note;
	Elf_Scn *scn;
	char *src, *osname;
	const char *abi;
	GElf_Ehdr elfhdr;
	GElf_Shdr shdr;
	int fd, i, ret;
	uint32_t version;

	version = 0;
	ret = -1;
	scn = NULL;
	abi = NULL;

	if (elf_version(EV_CURRENT) == EV_NONE) {
		warnx("ELF library initialization failed: %s",
		    elf_errmsg(-1));
		return (-1);
	}

	if ((fd = open("/bin/sh", O_RDONLY)) < 0) {
		warn("open()");
		return (-1);
	}

	if ((elf = elf_begin(fd, ELF_C_READ, NULL)) == NULL) {
		ret = -1;
		warnx("elf_begin() failed: %s.", elf_errmsg(-1));
		goto cleanup;
	}

	if (gelf_getehdr(elf, &elfhdr) == NULL) {
		ret = -1;
		warn("getehdr() failed: %s.", elf_errmsg(-1));
		goto cleanup;
	}

	while ((scn = elf_nextscn(elf, scn)) != NULL) {
		if (gelf_getshdr(scn, &shdr) != &shdr) {
			ret = -1;
			warn("getshdr() failed: %s.", elf_errmsg(-1));
			goto cleanup;
		}

		if (shdr.sh_type == SHT_NOTE)
			break;
	}

	if (scn == NULL) {
		ret = -1;
		warn("failed to get the note section");
		goto cleanup;
	}

	data = elf_getdata(scn, NULL);
	src = data->d_buf;
	for (;;) {
		memcpy(&note, src, sizeof(Elf_Note));
		src += sizeof(Elf_Note);
		if (note.n_type == NT_VERSION)
			break;
		src += note.n_namesz + note.n_descsz;
	}
	osname = src;
	src += note.n_namesz;
	if (elfhdr.e_ident[EI_DATA] == ELFDATA2MSB)
		version = be32dec(src);
	else
		version = le32dec(src);

	for (i = 0; osname[i] != '\0'; i++)
		osname[i] = (char)tolower(osname[i]);

	snprintf(dest, sz, "%s:%d:%s:%s",
	    osname, version / 100000,
	    elf_corres_to_string(mach_corres, (int)elfhdr.e_machine),
	    elf_corres_to_string(wordsize_corres,
	    (int)elfhdr.e_ident[EI_CLASS]));

	ret = 0;

	switch (elfhdr.e_machine) {
	case EM_ARM:
		snprintf(dest + strlen(dest), sz - strlen(dest),
		    ":%s:%s:%s", elf_corres_to_string(endian_corres,
		    (int)elfhdr.e_ident[EI_DATA]),
		    (elfhdr.e_flags & EF_ARM_NEW_ABI) > 0 ?
		    "eabi" : "oabi",
		    (elfhdr.e_flags & EF_ARM_VFP_FLOAT) > 0 ?
		    "softfp" : "vfp");
		break;
	case EM_MIPS:
		/*
		 * this is taken from binutils sources:
		 * include/elf/mips.h
		 * mapping is figured out from binutils:
		 * gas/config/tc-mips.c
		 */
		switch (elfhdr.e_flags & EF_MIPS_ABI) {
		case E_MIPS_ABI_O32:
			abi = "o32";
			break;
		case E_MIPS_ABI_N32:
			abi = "n32";
			break;
		default:
			if (elfhdr.e_ident[EI_DATA] ==
			    ELFCLASS32)
				abi = "o32";
			else if (elfhdr.e_ident[EI_DATA] ==
			    ELFCLASS64)
				abi = "n64";
			break;
		}
		snprintf(dest + strlen(dest), sz - strlen(dest),
		    ":%s:%s", elf_corres_to_string(endian_corres,
		    (int)elfhdr.e_ident[EI_DATA]), abi);
		break;
	}

cleanup:
	if (elf != NULL)
		elf_end(elf);

	close(fd);
	return (ret);
}

static int
extract_pkg_static(int fd, char *p, int sz)
{
	struct archive *a;
	struct archive_entry *ae;
	char *end;
	int ret, r;

	ret = -1;
	a = archive_read_new();
	if (a == NULL) {
		warn("archive_read_new");
		return (ret);
	}
	archive_read_support_compression_all(a);
	archive_read_support_format_tar(a);

	if (lseek(fd, 0, 0) == -1) {
		warn("lseek");
		goto cleanup;
	}

	if (archive_read_open_fd(a, fd, 4096) != ARCHIVE_OK) {
		warnx("archive_read_open_fd: %s", archive_error_string(a));
		goto cleanup;
	}

	ae = NULL;
	while ((r = archive_read_next_header(a, &ae)) == ARCHIVE_OK) {
		end = strrchr(archive_entry_pathname(ae), '/');
		if (end == NULL)
			continue;

		if (strcmp(end, "/pkg-static") == 0) {
			r = archive_read_extract(a, ae,
			    ARCHIVE_EXTRACT_OWNER | ARCHIVE_EXTRACT_PERM |
			    ARCHIVE_EXTRACT_TIME | ARCHIVE_EXTRACT_ACL |
			    ARCHIVE_EXTRACT_FFLAGS | ARCHIVE_EXTRACT_XATTR);
			strlcpy(p, archive_entry_pathname(ae), sz);
			break;
		}
	}

	if (r == ARCHIVE_OK)
		ret = 0;
	else
		warnx("fail to extract pkg-static");

cleanup:
	archive_read_finish(a);
	return (ret);

}

static int
install_pkg_static(char *path, char *pkgpath)
{
	int pstat;
	pid_t pid;

	switch ((pid = fork())) {
	case -1:
		return (-1);
	case 0:
		execl(path, "pkg-static", "add", pkgpath, (char *)NULL);
		_exit(1);
	default:
		break;
	}

	while (waitpid(pid, &pstat, 0) == -1)
		if (errno != EINTR)
			return (-1);

	if (WEXITSTATUS(pstat))
		return (WEXITSTATUS(pstat));
	else if (WIFSIGNALED(pstat))
		return (128 & (WTERMSIG(pstat)));
	return (pstat);
}

static int
bootstrap_pkg(void)
{
	FILE *remote;
	FILE *config;
	char *site;
	char url[MAXPATHLEN];
	char conf[MAXPATHLEN];
	char abi[BUFSIZ];
	char tmppkg[MAXPATHLEN];
	char buf[10240];
	char pkgstatic[MAXPATHLEN];
	int fd, retry, ret;
	struct url_stat st;
	off_t done, r;
	time_t now;
	time_t last;

	done = 0;
	last = 0;
	ret = -1;
	remote = NULL;
	config = NULL;

	printf("Bootstrapping pkg please wait\n");

	if (pkg_get_myabi(abi, MAXPATHLEN) != 0) {
		warnx("failed to determine the system ABI");
		return (-1);
	}

	if (getenv("PACKAGESITE") != NULL)
		snprintf(url, MAXPATHLEN, "%s/Latest/pkg.txz", getenv("PACKAGESITE"));
	else
		snprintf(url, MAXPATHLEN, "%s/%s/latest/Latest/pkg.txz",
		    getenv("PACKAGEROOT") ? getenv("PACKAGEROOT") : _PKGS_URL,
		    getenv("ABI") ? getenv("ABI") : abi);

	snprintf(tmppkg, MAXPATHLEN, "%s/pkg.txz.XXXXXX",
	    getenv("TMPDIR") ? getenv("TMPDIR") : _PATH_TMP);

	if ((fd = mkstemp(tmppkg)) == -1) {
		warn("mkstemp()");
		return (-1);
	}

	retry = 3;
	do {
		remote = fetchXGetURL(url, &st, "");
		if (remote == NULL)
			sleep(1);
	} while (remote == NULL && retry-- > 0);

	if (remote == NULL)
		goto fetchfail;

	while (done < st.size) {
		if ((r = fread(buf, 1, sizeof(buf), remote)) < 1)
			break;

		if (write(fd, buf, r) != r) {
			warn("write()");
			goto cleanup;
		}

		done += r;
		now = time(NULL);
		if (now > last || done == st.size)
			last = now;
	}

	if (ferror(remote))
		goto fetchfail;

	if ((ret = extract_pkg_static(fd, pkgstatic, MAXPATHLEN)) == 0)
		ret = install_pkg_static(pkgstatic, tmppkg);

	snprintf(conf, MAXPATHLEN, "%s/etc/pkg.conf",
	    getenv("LOCALBASE") ? getenv("LOCALBASE") : _LOCALBASE);

	if (access(conf, R_OK) == -1) {
		site = strrchr(url, '/');
		if (site == NULL)
			goto cleanup;
		site[0] = '\0';
		site = strrchr(url, '/');
		if (site == NULL)
			goto cleanup;
		site[0] = '\0';

		config = fopen(conf, "w+");
		if (config == NULL)
			goto cleanup;
		fprintf(config, "packagesite: %s\n", url);
		fclose(config);
	}

	goto cleanup;

fetchfail:
	warnx("Error fetching %s: %s", url, fetchLastErrString);

cleanup:
	if (remote != NULL)
		fclose(remote);
	close(fd);
	unlink(tmppkg);

	return (ret);
}

static const char confirmation_message[] =
"The package management tool is not yet installed on your system.\n"
"Do you want to fetch and install it now? [y/N]: ";

static int
pkg_query_yes_no(void)
{
	int ret, c;

	c = getchar();

	if (c == 'y' || c == 'Y')
		ret = 1;
	else
		ret = 0;

	while (c != '\n' && c != EOF)
		c = getchar();

	return (ret);
}

int
main(__unused int argc, char *argv[])
{
	char pkgpath[MAXPATHLEN];

	snprintf(pkgpath, MAXPATHLEN, "%s/sbin/pkg",
	    getenv("LOCALBASE") ? getenv("LOCALBASE") : _LOCALBASE);

	if (access(pkgpath, X_OK) == -1) {
		/*
		 * Do not ask for confirmation if either of stdin or stdout is
		 * not tty. Check the environment to see if user has answer
		 * tucked in there already.
		 */
		if (getenv("ASSUME_ALWAYS_YES") == NULL) {
			printf("%s", confirmation_message);
			if (!isatty(fileno(stdin)))
				exit(EXIT_FAILURE);

			if (pkg_query_yes_no() == 0)
				exit(EXIT_FAILURE);
		}
		if (bootstrap_pkg() != 0)
			exit(EXIT_FAILURE);
	}

	execv(pkgpath, argv);

	/* NOT REACHED */
	return (EXIT_FAILURE);
}