/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1993
 *      The Regents of the University of California.  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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/mman.h>
#include <sys/param.h>

#include <assert.h>
#include <ctype.h>
#include <dirent.h>
#include <err.h>
#include <iostream>
#include <sstream>
#include <stdio.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

#include "y.tab.h"
#include "config.h"
#include "configvers.h"

#ifndef TRUE
#define TRUE    (1)
#endif

#ifndef FALSE
#define FALSE   (0)
#endif

#define CDIR    "../compile/"

char    *machinename;
char    *machinearch;

struct cfgfile_head     cfgfiles;
struct cputype_head     cputype;
struct opt_head         opt, mkopt, rmopts;
struct opt_list_head    otab;
struct envvar_head      envvars;
struct hint_head        hints;
struct includepath_head includepath;

char *  PREFIX;
char    destdir[MAXPATHLEN];
char    srcdir[MAXPATHLEN];

int     debugging;
int     found_defaults;
int     incignore;
int     verbose;

/*
 * Preserve old behaviour in INCLUDE_CONFIG_FILE handling (files are included
 * literally).
 */
int     filebased = 0;
int     versreq;

static void configfile(void);
static void get_srcdir(void);
static void usage(void);
static void cleanheaders(char *);
static void kernconfdump(const char *);
static void badversion(void);
static void checkversion(void);

struct hdr_list {
        const char *h_name;
        struct hdr_list *h_next;
} *htab;

static std::stringstream line_buf;

/*
 * Config builds a set of files for building a UNIX
 * system given a description of the desired system.
 */
int
main(int argc, char **argv)
{

        struct stat buf;
        int ch, len;
        char *p;
        char *kernfile;
        struct includepath* ipath;
        int printmachine;
        bool cust_dest = false;

        printmachine = 0;
        kernfile = NULL;
        SLIST_INIT(&includepath);
        SLIST_INIT(&cputype);
        SLIST_INIT(&mkopt);
        SLIST_INIT(&opt);
        SLIST_INIT(&rmopts);
        STAILQ_INIT(&cfgfiles);
        STAILQ_INIT(&dtab);
        STAILQ_INIT(&fntab);
        STAILQ_INIT(&ftab);
        STAILQ_INIT(&hints);
        STAILQ_INIT(&envvars);
        STAILQ_INIT(&optfntab);
        while ((ch = getopt(argc, argv, "Cd:gI:mps:Vvx:")) != -1)
                switch (ch) {
                case 'C':
                        filebased = 1;
                        break;
                case 'd':
                        if (*destdir == '\0')
                                strlcpy(destdir, optarg, sizeof(destdir));
                        else
                                errx(EXIT_FAILURE, "directory already set");
                        cust_dest = true;
                        break;
                case 'g':
                        debugging++;
                        break;
                case 'I':
                        ipath = (struct includepath *) \
                                calloc(1, sizeof (struct includepath));
                        if (ipath == NULL)
                                err(EXIT_FAILURE, "calloc");
                        ipath->path = optarg;
                        SLIST_INSERT_HEAD(&includepath, ipath, path_next);
                        break;
                case 'm':
                        printmachine = 1;
                        break;
                case 's':
                        if (*srcdir == '\0')
                                strlcpy(srcdir, optarg, sizeof(srcdir));
                        else
                                errx(EXIT_FAILURE, "src directory already set");
                        break;
                case 'V':
                        printf("%d\n", CONFIGVERS);
                        exit(0);
                case 'v':
                        verbose++;
                        break;
                case 'x':
                        kernfile = optarg;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (kernfile != NULL) {
                kernconfdump(kernfile);
                exit(EXIT_SUCCESS);
        }

        if (argc != 1)
                usage();

        PREFIX = *argv;
        if (stat(PREFIX, &buf) != 0 || !S_ISREG(buf.st_mode))
                err(2, "%s", PREFIX);
        if (freopen("DEFAULTS", "r", stdin) != NULL) {
                found_defaults = 1;
                yyfile = "DEFAULTS";
        } else {
                if (freopen(PREFIX, "r", stdin) == NULL)
                        err(2, "%s", PREFIX);
                yyfile = PREFIX;
        }
        if (*destdir != '\0') {
                len = strlen(destdir);
                while (len > 1 && destdir[len - 1] == '/')
                        destdir[--len] = '\0';
                if (*srcdir == '\0')
                        get_srcdir();
        } else {
                strlcpy(destdir, CDIR, sizeof(destdir));
                strlcat(destdir, PREFIX, sizeof(destdir));
        }

        if (yyparse())
                exit(3);

        /*
         * Ensure that required elements (machine, cpu, ident) are present.
         */
        if (machinename == NULL) {
                printf("Specify machine type, e.g. ``machine i386''\n");
                exit(1);
        }
        if (ident == NULL) {
                printf("no ident line specified\n");
                exit(1);
        }
        if (SLIST_EMPTY(&cputype)) {
                printf("cpu type must be specified\n");
                exit(1);
        }
        checkversion();

        if (printmachine) {
                printf("%s\t%s\n",machinename,machinearch);
                exit(0);
        }

        /*
         * Make CDIR directory, if doing a default destination. Some version
         * control systems delete empty directories and this seemlessly copes.
         */
        if (!cust_dest && stat(CDIR, &buf))
                if (mkdir(CDIR, 0777))
                        err(2, "%s", CDIR);
        /* Create the compile directory */
        p = path((char *)NULL);
        if (stat(p, &buf)) {
                if (mkdir(p, 0777))
                        err(2, "%s", p);
        } else if (!S_ISDIR(buf.st_mode))
                errx(EXIT_FAILURE, "%s isn't a directory", p);

        configfile();                   /* put config file into kernel*/
        options();                      /* make options .h files */
        makefile();                     /* build Makefile */
        makeenv();                      /* build env.c */
        makehints();                    /* build hints.c */
        headers();                      /* make a lot of .h files */
        cleanheaders(p);
        printf("Kernel build directory is %s\n", p);
        printf("Don't forget to do ``make cleandepend && make depend''\n");
        exit(0);
}

/*
 * get_srcdir
 *      determine the root of the kernel source tree
 *      and save that in srcdir.
 */
static void
get_srcdir(void)
{
        struct stat lg, phy;
        char *p, *pwd;
        int i;

        if (realpath("../..", srcdir) == NULL)
                err(EXIT_FAILURE, "Unable to find root of source tree");
        if ((pwd = getenv("PWD")) != NULL && *pwd == '/' &&
            (pwd = strdup(pwd)) != NULL) {
                /* Remove the last two path components. */
                for (i = 0; i < 2; i++) {
                        if ((p = strrchr(pwd, '/')) == NULL) {
                                free(pwd);
                                return;
                        }
                        *p = '\0';
                }
                if (stat(pwd, &lg) != -1 && stat(srcdir, &phy) != -1 &&
                    lg.st_dev == phy.st_dev && lg.st_ino == phy.st_ino)
                        strlcpy(srcdir, pwd, MAXPATHLEN);
                free(pwd);
        }
}

static void
usage(void)
{

        fprintf(stderr,
            "usage: config [-CgmpV] [-d destdir] [-s srcdir] sysname\n");
        fprintf(stderr, "       config -x kernel\n");
        exit(EX_USAGE);
}

static void
init_line_buf(void)
{

        line_buf.str("");
}

static std::string
get_line_buf(void)
{

        line_buf.flush();
        if (!line_buf.good()) {
                errx(EXIT_FAILURE, "failed to generate line buffer, "
                    "partial line = %s", line_buf.str().c_str());
        }

        return line_buf.str();
}

/*
 * get_word
 *      returns EOF on end of file
 *      NULL on end of line
 *      pointer to the word otherwise
 */
configword
get_word(FILE *fp)
{
        int ch;
        int escaped_nl = 0;

        init_line_buf();
begin:
        while ((ch = getc(fp)) != EOF)
                if (ch != ' ' && ch != '\t')
                        break;
        if (ch == EOF)
                return (configword().eof(true));
        if (ch == '\\'){
                escaped_nl = 1;
                goto begin;
        }
        if (ch == '\n') {
                if (escaped_nl){
                        escaped_nl = 0;
                        goto begin;
                }
                else
                        return (configword().eol(true));
        }
        line_buf << (char)ch;
        /* Negation operator is a word by itself. */
        if (ch == '!') {
                return (configword(get_line_buf()));
        }
        while ((ch = getc(fp)) != EOF) {
                if (isspace(ch))
                        break;
                line_buf << (char)ch;
        }
        if (ch == EOF)
                return (configword().eof(true));
        (void) ungetc(ch, fp);
        return (configword(get_line_buf()));
}

/*
 * get_quoted_word
 *      like get_word but will accept something in double or single quotes
 *      (to allow embedded spaces).
 */
configword
get_quoted_word(FILE *fp)
{
        int ch;
        int escaped_nl = 0;

        init_line_buf();
begin:
        while ((ch = getc(fp)) != EOF)
                if (ch != ' ' && ch != '\t')
                        break;
        if (ch == EOF)
                return (configword().eof(true));
        if (ch == '\\'){
                escaped_nl = 1;
                goto begin;
        }
        if (ch == '\n') {
                if (escaped_nl){
                        escaped_nl = 0;
                        goto begin;
                }
                else
                        return (configword().eol(true));
        }
        if (ch == '"' || ch == '\'') {
                int quote = ch;

                escaped_nl = 0;
                while ((ch = getc(fp)) != EOF) {
                        if (ch == quote && !escaped_nl)
                                break;
                        if (ch == '\n' && !escaped_nl) {
                                printf("config: missing quote reading `%s'\n",
                                        get_line_buf().c_str());
                                exit(2);
                        }
                        if (ch == '\\' && !escaped_nl) {
                                escaped_nl = 1;
                                continue;
                        }
                        if (ch != quote && escaped_nl)
                                line_buf << "\\";
                        line_buf << (char)ch;
                        escaped_nl = 0;
                }
        } else {
                line_buf << (char)ch;
                while ((ch = getc(fp)) != EOF) {
                        if (isspace(ch))
                                break;
                        line_buf << (char)ch;
                }
                if (ch != EOF)
                        (void) ungetc(ch, fp);
        }
        if (ch == EOF)
                return (configword().eof(true));
        return (configword(get_line_buf()));
}

/*
 * prepend the path to a filename
 */
char *
path(const char *file)
{
        char *cp = NULL;

        if (file)
                asprintf(&cp, "%s/%s", destdir, file);
        else
                cp = strdup(destdir);
        if (cp == NULL)
                err(EXIT_FAILURE, "malloc");
        return (cp);
}

/*
 * Generate configuration file based on actual settings. With this mode, user
 * will be able to obtain and build conifguration file with one command.
 */
static void
configfile_dynamic(std::ostringstream &cfg)
{
        struct cputype *cput;
        struct device *d;
        struct opt *ol;
        char *lend;
        unsigned int i;

        asprintf(&lend, "\\n\\\n");
        assert(lend != NULL);
        cfg << "options\t" << OPT_AUTOGEN << lend;
        cfg << "ident\t" << ident << lend;
        cfg << "machine\t" << machinename << lend;
        SLIST_FOREACH(cput, &cputype, cpu_next)
                cfg << "cpu\t" << cput->cpu_name << lend;
        SLIST_FOREACH(ol, &mkopt, op_next)
                cfg << "makeoptions\t" << ol->op_name << '=' <<
                    ol->op_value << lend;
        SLIST_FOREACH(ol, &opt, op_next) {
                if (strncmp(ol->op_name, "DEV_", 4) == 0)
                        continue;
                cfg << "options\t" << ol->op_name;
                if (ol->op_value != NULL) {
                        cfg << '=';
                        for (i = 0; i < strlen(ol->op_value); i++) {
                                if (ol->op_value[i] == '"')
                                        cfg << '\\' << ol->op_value[i];
                                else
                                        cfg << ol->op_value[i];
                        }
                }

                cfg << lend;
        }
        /*
         * Mark this file as containing everything we need.
         */
        STAILQ_FOREACH(d, &dtab, d_next)
                cfg << "device\t" << d->d_name << lend;
        free(lend);
}

/*
 * Generate file from the configuration files.
 */
static void
configfile_filebased(std::ostringstream &cfg)
{
        FILE *cff;
        struct cfgfile *cf;
        int i;

        /*
         * Try to read all configuration files. Since those will be present as
         * C string in the macro, we have to slash their ends then the line
         * wraps.
         */
        STAILQ_FOREACH(cf, &cfgfiles, cfg_next) {
                cff = fopen(cf->cfg_path, "r");
                if (cff == NULL) {
                        warn("Couldn't open file %s", cf->cfg_path);
                        continue;
                }
                while ((i = getc(cff)) != EOF) {
                        if (i == '\n')
                                cfg << "\\n\\\n";
                        else if (i == '"' || i == '\'')
                                cfg << '\\' << i;
                        else
                                cfg << i;
                }
                fclose(cff);
        }
}

static void
configfile(void)
{
        FILE *fo;
        std::ostringstream cfg;
        char *p;

        /* Add main configuration file to the list of files to be included */
        cfgfile_add(PREFIX);
        p = path("config.c.new");
        fo = fopen(p, "w");
        if (!fo)
                err(2, "%s", p);
        free(p);

        if (filebased) {
                /* Is needed, can be used for backward compatibility. */
                configfile_filebased(cfg);
        } else {
                configfile_dynamic(cfg);
        }

        cfg.flush();
        /* 
         * We print first part of the template, replace our tag with
         * configuration files content and later continue writing our
         * template.
         */
        p = strstr(kernconfstr, KERNCONFTAG);
        if (p == NULL)
                errx(EXIT_FAILURE, "Something went terribly wrong!");
        *p = '\0';
        fprintf(fo, "%s", kernconfstr);
        fprintf(fo, "%s", cfg.str().c_str());
        p += strlen(KERNCONFTAG);
        fprintf(fo, "%s", p);
        fclose(fo);
        moveifchanged("config.c.new", "config.c");
        cfgfile_removeall();
}

/*
 * moveifchanged --
 *      compare two files; rename if changed.
 */
void
moveifchanged(const char *from_name, const char *to_name)
{
        char *p, *q;
        char *from_path, *to_path;
        int changed;
        size_t tsize;
        struct stat from_sb, to_sb;
        int from_fd, to_fd;

        changed = 0;

        from_path = path(from_name);
        to_path = path(to_name);
        if ((from_fd = open(from_path, O_RDONLY)) < 0)
                err(EX_OSERR, "moveifchanged open(%s)", from_name);

        if ((to_fd = open(to_path, O_RDONLY)) < 0)
                changed++;

        if (!changed && fstat(from_fd, &from_sb) < 0)
                err(EX_OSERR, "moveifchanged fstat(%s)", from_path);

        if (!changed && fstat(to_fd, &to_sb) < 0)
                err(EX_OSERR, "moveifchanged fstat(%s)", to_path);

        if (!changed && from_sb.st_size != to_sb.st_size)
                changed++;

        if (!changed) {
                tsize = (size_t)from_sb.st_size;

                p = (char *)mmap(NULL, tsize, PROT_READ, MAP_SHARED, from_fd,
                    (off_t)0);
                if (p == MAP_FAILED)
                        err(EX_OSERR, "mmap %s", from_path);
                q = (char *)mmap(NULL, tsize, PROT_READ, MAP_SHARED, to_fd,
                    (off_t)0);
                if (q == MAP_FAILED)
                        err(EX_OSERR, "mmap %s", to_path);

                changed = memcmp(p, q, tsize);
                munmap(p, tsize);
                munmap(q, tsize);
        }

        if (changed) {
                if (rename(from_path, to_path) < 0)
                        err(EX_OSERR, "rename(%s, %s)", from_path, to_path);
        } else {
                if (unlink(from_path) < 0)
                        err(EX_OSERR, "unlink(%s)", from_path);
        }

        close(from_fd);
        if (to_fd >= 0)
                close(to_fd);

        free(from_path);
        free(to_path);
}

static void
cleanheaders(char *p)
{
        DIR *dirp;
        struct dirent *dp;
        struct file_list *fl;
        struct hdr_list *hl;
        size_t len;

        remember("y.tab.h");
        remember("setdefs.h");
        STAILQ_FOREACH(fl, &ftab, f_next)
                remember(fl->f_fn);

        /*
         * Scan the build directory and clean out stuff that looks like
         * it might have been a leftover NFOO header, etc.
         */
        if ((dirp = opendir(p)) == NULL)
                err(EX_OSERR, "opendir %s", p);
        while ((dp = readdir(dirp)) != NULL) {
                len = strlen(dp->d_name);
                /* Skip non-headers */
                if (len < 2 || dp->d_name[len - 2] != '.' ||
                    dp->d_name[len - 1] != 'h')
                        continue;
                /* Skip special stuff, eg: bus_if.h, but check opt_*.h */
                if (strchr(dp->d_name, '_') &&
                    strncmp(dp->d_name, "opt_", 4) != 0)
                        continue;
                /* Check if it is a target file */
                for (hl = htab; hl != NULL; hl = hl->h_next) {
                        if (eq(dp->d_name, hl->h_name)) {
                                break;
                        }
                }
                if (hl)
                        continue;
                printf("Removing stale header: %s\n", dp->d_name);
                p = path(dp->d_name);
                if (unlink(p) == -1)
                        warn("unlink %s", dp->d_name);
                free(p);
        }
        (void)closedir(dirp);
}

void
remember(const char *file)
{
        const char *s;
        struct hdr_list *hl;

        if ((s = strrchr(file, '/')) != NULL)
                s = ns(s + 1);
        else
                s = ns(file);

        if (strchr(s, '_') && strncmp(s, "opt_", 4) != 0) {
                free(__DECONST(char *, s));
                return;
        }
        for (hl = htab; hl != NULL; hl = hl->h_next) {
                if (eq(s, hl->h_name)) {
                        free(__DECONST(char *, s));
                        return;
                }
        }
        hl = (struct hdr_list *)calloc(1, sizeof(*hl));
        if (hl == NULL)
                err(EXIT_FAILURE, "calloc");
        hl->h_name = s;
        hl->h_next = htab;
        htab = hl;
}

/*
 * This one is quick hack. Will be probably moved to elf(3) interface.
 * It takes kernel configuration file name, passes it as an argument to
 * elfdump -a, which output is parsed by some UNIX tools...
 */
static void
kernconfdump(const char *file)
{
        struct stat st;
        FILE *fp, *pp;
        int error, osz, r;
        size_t i, off, size, t1, t2, align;
        char *cmd, *o;

        r = open(file, O_RDONLY);
        if (r == -1)
                err(EXIT_FAILURE, "Couldn't open file '%s'", file);
        error = fstat(r, &st);
        if (error == -1)
                err(EXIT_FAILURE, "fstat() failed");
        if (S_ISDIR(st.st_mode))
                errx(EXIT_FAILURE, "'%s' is a directory", file);
        fp = fdopen(r, "r");
        if (fp == NULL)
                err(EXIT_FAILURE, "fdopen() failed");
        osz = 1024;
        o = (char *)calloc(1, osz);
        if (o == NULL)
                err(EXIT_FAILURE, "Couldn't allocate memory");
        /* ELF note section header. */
        asprintf(&cmd, "/usr/bin/elfdump -c %s | grep -A 8 kern_conf"
            "| tail -5 | cut -d ' ' -f 2 | paste - - - - -", file);
        if (cmd == NULL)
                errx(EXIT_FAILURE, "asprintf() failed");
        pp = popen(cmd, "r");
        if (pp == NULL)
                errx(EXIT_FAILURE, "popen() failed");
        free(cmd);
        (void)fread(o, osz, 1, pp);
        pclose(pp);
        r = sscanf(o, "%zu%zu%zu%zu%zu", &off, &size, &t1, &t2, &align);
        free(o);
        if (size > SIZE_MAX - off || off + size > (size_t)st.st_size)
                errx(EXIT_FAILURE, "%s: incoherent ELF headers", file);
        if (r != 5)
                errx(EXIT_FAILURE, "File %s doesn't contain configuration "
                    "file. Either unsupported, or not compiled with "
                    "INCLUDE_CONFIG_FILE", file);
        r = fseek(fp, off, SEEK_CUR);
        if (r != 0)
                err(EXIT_FAILURE, "fseek() failed");
        for (i = 0; i < size; i++) {
                r = fgetc(fp);
                if (r == EOF)
                        break;
                if (r == '\0') {
                        assert(i == size - 1 &&
                            ("\\0 found in the middle of a file"));
                        break;
                }
                fputc(r, stdout);
        }
        fclose(fp);
}

static void
badversion(void)
{
        fprintf(stderr, "ERROR: version of config(8) does not match kernel!\n");
        fprintf(stderr, "config version = %d, ", CONFIGVERS);
        fprintf(stderr, "version required = %d\n\n", versreq);
        fprintf(stderr, "Make sure that /usr/src/usr.sbin/config is in sync\n");
        fprintf(stderr, "with your /usr/src/sys and install a new config binary\n");
        fprintf(stderr, "before trying this again.\n\n");
        fprintf(stderr, "If running the new config fails check your config\n");
        fprintf(stderr, "file against the GENERIC or LINT config files for\n");
        fprintf(stderr, "changes in config syntax, or option/device naming\n");
        fprintf(stderr, "conventions\n\n");
        exit(1);
}

static void
checkversion(void)
{
        FILE *ifp;
        char line[BUFSIZ];

        ifp = open_makefile_template();
        while (fgets(line, BUFSIZ, ifp) != 0) {
                if (*line != '%')
                        continue;
                if (strncmp(line, "%VERSREQ=", 9) != 0)
                        continue;
                versreq = atoi(line + 9);
                if (MAJOR_VERS(versreq) == MAJOR_VERS(CONFIGVERS) &&
                    versreq <= CONFIGVERS)
                        continue;
                badversion();
        }
        fclose(ifp);
}