/*-
 * Copyright (c) 2004, 2005 Lev Walkin <vlm@lionet.info>. 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.
 *
 * $Id$
 */
#include "sys-common.h"

#include <asn1parser.h> /* For static string tables */

#include <asn_application.h>
#include <constraints.c>
#include <ber_tlv_tag.c>
#include <ber_tlv_length.c>

#undef COPYRIGHT
#define COPYRIGHT "Copyright (c) 2004, 2005 Lev Walkin <vlm@lionet.info>\n"

static void usage(const char *av0, int); /* Print the Usage screen and exit */
static int process(const char *fname);   /* Perform the BER decoding */
static int process_line(const char *fname, char *line, int lineno);

static int no_validation; /* -n */

int
main(int ac, char **av) {
    int ch; /* Command line character */
    int i;  /* Index in some loops */

    /*
     * Process command-line options.
     */
    while((ch = getopt(ac, av, "nhv")) != -1) switch(ch) {
        case 'n':
            no_validation++;
            break;
        case 'v':
            usage(av[0], 1);
            break;
        case 'h':
        default:
            usage(av[0], 0);
        }

    /*
     * Ensure that there are some input files present.
     */
    if(ac > optind) {
        ac -= optind;
        av += optind;
    } else {
        fprintf(stderr, "%s: No input files specified\n", av[0]);
        exit(1);
    }

    setvbuf(stdout, 0, _IOLBF, 0);

    /*
     * Iterate over input files and parse each.
     * All syntax trees from all files will be bundled together.
     */
    for(i = 0; i < ac; i++) {
        if(process(av[i])) exit(EX_DATAERR);
    }

    return 0;
}

/*
 * Print the usage screen and exit(EX_USAGE).
 */
static void
usage(const char *av0, int copyright_only) {
    fprintf(stderr,
            "Convert unber(1)'s output back into BER, "
            "v" VERSION "\n" COPYRIGHT);
    if(copyright_only) exit(0);
    fprintf(stderr,
            "Usage: %s [-n] [-] [file ...]\n"
            "Options:\n"
            "  -n      Disable XML input validation\n",
            av0);
    exit(EX_USAGE);
}

/*
 * Open the file and initiate recursive processing.
 */
static int
process(const char *fname) {
    char buf[8192];
    char *collector = 0;
    size_t collector_size = sizeof(buf);
    size_t collector_offset = 0;
    int lineno = 0;
    FILE *fp;

    if(strcmp(fname, "-")) {
        fp = fopen(fname, "r");
        if(!fp) {
            perror(fname);
            return -1;
        }
    } else {
        fp = stdin;
    }


    while(fgets(buf, sizeof(buf), fp) || !feof(fp)) {
        size_t len = strlen(buf);

        if(!len) continue;
        if(collector_offset || buf[len - 1] != '\n') {
            if((collector_size - collector_offset) <= len || !collector) {
                collector_size <<= 1;
                collector = REALLOC(collector, collector_size);
                if(!collector) {
                    perror("realloc()");
                    exit(EX_OSERR);
                }
            }
            memcpy(collector + collector_offset, buf, len + 1);
            collector_offset += len;
        }
        if(buf[len - 1] != '\n') continue;

        if(collector_offset) {
            assert(collector[collector_offset - 1] == '\n');
            process_line(fname, collector, ++lineno);
            collector_offset = 0;
        } else {
            process_line(fname, buf, ++lineno);
        }
    }

    if(fp != stdin) fclose(fp);

    return 0;
}

static int
process_line(const char *fname, char *line, int lineno) {
    char buf[32];
    char *op;      /* '<' */
    char *cl;      /* '>' */
    char *tcl_pos; /* tag class (T=") position */
    char *tl_pos;  /* tag length (TL=") position */
    char *v_pos;   /* value length (V=") position */
    int constr;
    ber_tlv_tag_t tag_value;
    ber_tlv_tag_t tag_class;
    ber_tlv_tag_t tlv_tag;
    ber_tlv_len_t tlv_len;
    ber_tlv_len_t opt_tl_len; /* optional TL length */
    ssize_t ret;

    /* Skip the whitespace */
    for(; *line == ' ' || *line == '\t'; line++)
        ;

    /* Find a tag opening angle bracket */
    op = line;
    switch(*op) {
    case '<': /* That's what we want! A tag opening */
        break;
    case '\r':
    case '\n':
    case '#': /* This is a comment */
        return 0;
    case '-': /* This is a comment (dash-dash) */
        if(op[1] == '-') {
            return 0;
        }
        /* Fall through */
    default:
        fprintf(stderr, "%s: Missing '<' after whitespace at line %d\n", fname,
                lineno);
        exit(EX_DATAERR);
    }

    /* Find a tag closing angle bracket */
    for(; *line && *line != '>'; line++) {
        if(*line < ' ') {
            fprintf(stderr, "%s: Invalid charset (%d) at line %d\n", fname,
                    *(const unsigned char *)line, lineno);
            exit(EX_DATAERR);
        }
    }
    cl = line;
    if(*cl != '>') {
        fprintf(stderr, "%s: Missing '>' at line %d\n", fname, lineno);
        exit(EX_DATAERR);
    }

    /* Ignore closing tags */
    if(op[1] == '/') {
        if(strchr(cl, '<')) { /* We are not very robust */
            fprintf(stderr, "%s: Multiple tags per line at line %d\n", fname,
                    lineno);
            exit(EX_DATAERR);
        }
        /* End-of-content octets */
        if(op[2] == 'I') {
            buf[0] = buf[1] = 0x00;
            fwrite(buf, 1, 2, stdout);
        }
        return 0;
    }

    switch(op[1]) {
    case '!':
        return 0; /* A comment */
    case '?':
        return 0; /* An XML preamble */
    case 'C':
        constr = 1;
        break;
    case 'P':
        constr = 0;
        break;
    case 'I':
        constr = 2;
        break;
    default:
        fprintf(stderr,
                "%s: Expected \"C\"/\"P\"/\"I\" as the XML tag name (%c) at "
                "line %d\n",
                fname, op[1], lineno);
        exit(EX_DATAERR);
    }

    *cl = '\0';
    if(cl[-1] == 'F') {
        fprintf(stderr,
                "%s: Detected pretty-printing of primitive types at line %d. "
                "Re-run `unber` with -p option to disable pretty-printing.\n",
                fname, lineno);
        exit(EX_DATAERR);
    }

    tcl_pos = strstr(op, "T=\"[");
    tl_pos = strstr(op, "TL=\"");
    v_pos = strstr(op, "V=\"");
    if(!tcl_pos || (!v_pos && constr != 2)) {
        fprintf(stderr, "%s: Mandatory attribute %s is not found at line %d\n",
                fname, (!tcl_pos) ? "T" : "V", lineno);
        exit(EX_DATAERR);
    }
    errno = 0;
    opt_tl_len = tl_pos ? strtoul(tl_pos + 4, 0, 10) : 0;
    if(constr == 2) {
        tlv_len = 0;
    } else {
        tlv_len = strtoul(v_pos + 3, 0, 10);
    }
    if(errno || (opt_tl_len && opt_tl_len < 2) || tlv_len < 0) {
        fprintf(stderr, "%s: Invalid TL or V value at line %d\n", fname,
                lineno);
        exit(EX_DATAERR);
    }

    /* clang-format off */
	tcl_pos += 4;
	switch(*tcl_pos) {
	case 'U':	/* UNIVERSAL */
		tag_class = ASN_TAG_CLASS_UNIVERSAL; break;
	case 'P':	/* PRIVATE */
		tag_class = ASN_TAG_CLASS_PRIVATE; break;
	case 'A':	/* APPLICATION */
		tag_class = ASN_TAG_CLASS_APPLICATION; break;
	case '0': case '1': case '2': case '3': case '4':
	case '5': case '6': case '7': case '8': case '9':	/* context */
		tag_class = ASN_TAG_CLASS_CONTEXT; break;
	default:
		fprintf(stderr, "%s: Invalid tag class (%c) at line %d\n",
			fname, tcl_pos[4], lineno);
		exit(EX_DATAERR);
	}
	for(;; tcl_pos++) {
		switch(*tcl_pos) {
		case '"': tcl_pos = "";
		case '\0':
		case '0': case '1': case '2': case '3': case '4':
		case '5': case '6': case '7': case '8': case '9':
			break;
		default: continue;
		}
		break;
	}
    /* clang-format on */

    unsigned long tag_value_UL;
    errno = 0;
    if(!*tcl_pos || ((tag_value_UL = strtoul(tcl_pos, 0, 10)) > UINT_MAX)
       || errno) {
        fprintf(stderr, "%s: Invalid tag value (%c) at line %d\n", fname,
                *tcl_pos, lineno);
        exit(EX_DATAERR);
    } else {
        tag_value = tag_value_UL;
    }
    tlv_tag = ((tag_value << 2) | tag_class);

    ret = ber_tlv_tag_serialize(tlv_tag, buf, sizeof(buf));
    assert(ret >= 1 && (size_t)ret < sizeof(buf));
    if(constr == 2) {
        buf[ret] = 0x80;
        ret += 1;
    } else {
        ret += der_tlv_length_serialize(tlv_len, buf + ret, sizeof(buf) - ret);
        assert(ret >= 2 && (size_t)ret < sizeof(buf));
    }
    if(opt_tl_len && ret != opt_tl_len) {
        fprintf(stderr,
                "%s: Cannot encode TL at line %d "
                "in the given number of bytes (%ld!=%ld)\n",
                fname, lineno, (long)ret, (long)opt_tl_len);
        exit(EX_DATAERR);
    }
    if(constr) *buf |= 0x20; /* Enable "constructed" bit */
    fwrite(buf, 1, ret, stdout);

    if(!constr) {
        ber_tlv_len_t len;
        for(len = 0, cl++; *cl && *cl != '<'; cl++, len++) {
            unsigned char v;
            int h;
            if(*cl != '&') {
                fputc(*cl, stdout);
                continue;
            }
            cl++;
            if(*cl != '#') {
                fputc(*cl, stdout);
                continue;
            }
            cl++;
            if(*cl != 'x') {
                fprintf(stderr, "%s: Expected \"&#xNN;\" at line %d\n", fname,
                        lineno);
                exit(EX_DATAERR);
            }
            for(v = 0, h = 0; h < 2; h++) {
                unsigned char clv = *++cl;
                v <<= 4;
                /* clang-format off */
			switch(clv) {
			case '0': case '1': case '2': case '3': case '4':
			case '5': case '6': case '7': case '8': case '9':
				v |= clv - '0'; break;
			case 'A': case 'B': case 'C':
			case 'D': case 'E': case 'F':
				v |= clv - 'A' + 10; break;
			case 'a': case 'b': case 'c':
			case 'd': case 'e': case 'f':
				v |= clv - 'a' + 10; break;
			default:
				fprintf(stderr,
					"%s: Expected \"&#xNN;\" at line %d (%c)\n",
					fname, lineno, clv);
				exit(EX_DATAERR);
			}
                /* clang-format on */
            }
            cl++;
            if(*cl != ';') {
                fprintf(stderr, "%s: Expected \"&#xNN;\" at line %d\n", fname,
                        lineno);
                exit(EX_DATAERR);
            }
            fputc(v, stdout);
        }
        if(len != tlv_len) {
            if(no_validation) fprintf(stderr, "Warning: ");
            fprintf(stderr,
                    "%s: Could not encode value of %ld chars "
                    "at line %d in %ld bytes\n",
                    fname, (long)len, lineno, (long)tlv_len);
            if(!no_validation) exit(EX_DATAERR);
        }
    }

    return 0;
}