/*      $Id: mandoc.c,v 1.119 2021/08/10 12:55:03 schwarze Exp $ */
/*
 * Copyright (c) 2008-2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
 * Copyright (c) 2011-2015, 2017-2021 Ingo Schwarze <schwarze@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include "config.h"

#include <sys/types.h>

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

#include "mandoc_aux.h"
#include "mandoc.h"
#include "roff.h"
#include "libmandoc.h"
#include "roff_int.h"

static  int      a2time(time_t *, const char *, const char *);
static  char    *time2a(time_t);


enum mandoc_esc
mandoc_font(const char *cp, int sz)
{
        switch (sz) {
        case 0:
                return ESCAPE_FONTPREV;
        case 1:
                switch (cp[0]) {
                case 'B':
                case '3':
                        return ESCAPE_FONTBOLD;
                case 'I':
                case '2':
                        return ESCAPE_FONTITALIC;
                case 'P':
                        return ESCAPE_FONTPREV;
                case 'R':
                case '1':
                        return ESCAPE_FONTROMAN;
                case '4':
                        return ESCAPE_FONTBI;
                default:
                        return ESCAPE_ERROR;
                }
        case 2:
                switch (cp[0]) {
                case 'B':
                        switch (cp[1]) {
                        case 'I':
                                return ESCAPE_FONTBI;
                        default:
                                return ESCAPE_ERROR;
                        }
                case 'C':
                        switch (cp[1]) {
                        case 'B':
                                return ESCAPE_FONTCB;
                        case 'I':
                                return ESCAPE_FONTCI;
                        case 'R':
                        case 'W':
                                return ESCAPE_FONTCR;
                        default:
                                return ESCAPE_ERROR;
                        }
                default:
                        return ESCAPE_ERROR;
                }
        default:
                return ESCAPE_ERROR;
        }
}

enum mandoc_esc
mandoc_escape(const char **end, const char **start, int *sz)
{
        const char      *local_start;
        int              local_sz, c, i;
        char             term;
        enum mandoc_esc  gly;

        /*
         * When the caller doesn't provide return storage,
         * use local storage.
         */

        if (NULL == start)
                start = &local_start;
        if (NULL == sz)
                sz = &local_sz;

        /*
         * Treat "\E" just like "\";
         * it only makes a difference in copy mode.
         */

        if (**end == 'E')
                ++*end;

        /*
         * Beyond the backslash, at least one input character
         * is part of the escape sequence.  With one exception
         * (see below), that character won't be returned.
         */

        gly = ESCAPE_ERROR;
        *start = ++*end;
        *sz = 0;
        term = '\0';

        switch ((*start)[-1]) {
        /*
         * First the glyphs.  There are several different forms of
         * these, but each eventually returns a substring of the glyph
         * name.
         */
        case '(':
                gly = ESCAPE_SPECIAL;
                *sz = 2;
                break;
        case '[':
                if (**start == ' ') {
                        ++*end;
                        return ESCAPE_ERROR;
                }
                gly = ESCAPE_SPECIAL;
                term = ']';
                break;
        case 'C':
                if ('\'' != **start)
                        return ESCAPE_ERROR;
                *start = ++*end;
                gly = ESCAPE_SPECIAL;
                term = '\'';
                break;

        /*
         * Escapes taking no arguments at all.
         */
        case '!':
        case '?':
                return ESCAPE_UNSUPP;
        case '%':
        case '&':
        case ')':
        case ',':
        case '/':
        case '^':
        case 'a':
        case 'd':
        case 'r':
        case 't':
        case 'u':
        case '{':
        case '|':
        case '}':
                return ESCAPE_IGNORE;
        case 'c':
                return ESCAPE_NOSPACE;
        case 'p':
                return ESCAPE_BREAK;

        /*
         * The \z escape is supposed to output the following
         * character without advancing the cursor position.
         * Since we are mostly dealing with terminal mode,
         * let us just skip the next character.
         */
        case 'z':
                return ESCAPE_SKIPCHAR;

        /*
         * Handle all triggers matching \X(xy, \Xx, and \X[xxxx], where
         * 'X' is the trigger.  These have opaque sub-strings.
         */
        case 'F':
        case 'f':
        case 'g':
        case 'k':
        case 'M':
        case 'm':
        case 'n':
        case 'O':
        case 'V':
        case 'Y':
        case '*':
                switch ((*start)[-1]) {
                case 'f':
                        gly = ESCAPE_FONT;
                        break;
                case '*':
                        gly = ESCAPE_DEVICE;
                        break;
                default:
                        gly = ESCAPE_IGNORE;
                        break;
                }
                switch (**start) {
                case '(':
                        if ((*start)[-1] == 'O')
                                gly = ESCAPE_ERROR;
                        *start = ++*end;
                        *sz = 2;
                        break;
                case '[':
                        if ((*start)[-1] == 'O')
                                gly = (*start)[1] == '5' ?
                                    ESCAPE_UNSUPP : ESCAPE_ERROR;
                        *start = ++*end;
                        term = ']';
                        break;
                default:
                        if ((*start)[-1] == 'O') {
                                switch (**start) {
                                case '0':
                                        gly = ESCAPE_UNSUPP;
                                        break;
                                case '1':
                                case '2':
                                case '3':
                                case '4':
                                        break;
                                default:
                                        gly = ESCAPE_ERROR;
                                        break;
                                }
                        }
                        *sz = 1;
                        break;
                }
                break;

        /*
         * These escapes are of the form \X'Y', where 'X' is the trigger
         * and 'Y' is any string.  These have opaque sub-strings.
         * The \B and \w escapes are handled in roff.c, roff_res().
         */
        case 'A':
        case 'b':
        case 'D':
        case 'R':
        case 'X':
        case 'Z':
                gly = ESCAPE_IGNORE;
                /* FALLTHROUGH */
        case 'o':
                if (**start == '\0')
                        return ESCAPE_ERROR;
                if (gly == ESCAPE_ERROR)
                        gly = ESCAPE_OVERSTRIKE;
                term = **start;
                *start = ++*end;
                break;

        /*
         * These escapes are of the form \X'N', where 'X' is the trigger
         * and 'N' resolves to a numerical expression.
         */
        case 'h':
        case 'H':
        case 'L':
        case 'l':
        case 'S':
        case 'v':
        case 'x':
                if (strchr(" %&()*+-./0123456789:<=>", **start)) {
                        if ('\0' != **start)
                                ++*end;
                        return ESCAPE_ERROR;
                }
                switch ((*start)[-1]) {
                case 'h':
                        gly = ESCAPE_HORIZ;
                        break;
                case 'l':
                        gly = ESCAPE_HLINE;
                        break;
                default:
                        gly = ESCAPE_IGNORE;
                        break;
                }
                term = **start;
                *start = ++*end;
                break;

        /*
         * Special handling for the numbered character escape.
         * XXX Do any other escapes need similar handling?
         */
        case 'N':
                if ('\0' == **start)
                        return ESCAPE_ERROR;
                (*end)++;
                if (isdigit((unsigned char)**start)) {
                        *sz = 1;
                        return ESCAPE_IGNORE;
                }
                (*start)++;
                while (isdigit((unsigned char)**end))
                        (*end)++;
                *sz = *end - *start;
                if ('\0' != **end)
                        (*end)++;
                return ESCAPE_NUMBERED;

        /*
         * Sizes get a special category of their own.
         */
        case 's':
                gly = ESCAPE_IGNORE;

                /* See +/- counts as a sign. */
                if ('+' == **end || '-' == **end || ASCII_HYPH == **end)
                        *start = ++*end;

                switch (**end) {
                case '(':
                        *start = ++*end;
                        *sz = 2;
                        break;
                case '[':
                        *start = ++*end;
                        term = ']';
                        break;
                case '\'':
                        *start = ++*end;
                        term = '\'';
                        break;
                case '3':
                case '2':
                case '1':
                        *sz = (*end)[-1] == 's' &&
                            isdigit((unsigned char)(*end)[1]) ? 2 : 1;
                        break;
                default:
                        *sz = 1;
                        break;
                }

                break;

        /*
         * Several special characters can be encoded as
         * one-byte escape sequences without using \[].
         */
        case ' ':
        case '\'':
        case '-':
        case '.':
        case '0':
        case ':':
        case '_':
        case '`':
        case 'e':
        case '~':
                gly = ESCAPE_SPECIAL;
                /* FALLTHROUGH */
        default:
                if (gly == ESCAPE_ERROR)
                        gly = ESCAPE_UNDEF;
                *start = --*end;
                *sz = 1;
                break;
        }

        /*
         * Read up to the terminating character,
         * paying attention to nested escapes.
         */

        if ('\0' != term) {
                while (**end != term) {
                        switch (**end) {
                        case '\0':
                                return ESCAPE_ERROR;
                        case '\\':
                                (*end)++;
                                if (ESCAPE_ERROR ==
                                    mandoc_escape(end, NULL, NULL))
                                        return ESCAPE_ERROR;
                                break;
                        default:
                                (*end)++;
                                break;
                        }
                }
                *sz = (*end)++ - *start;

                /*
                 * The file chars.c only provides one common list
                 * of character names, but \[-] == \- is the only
                 * one of the characters with one-byte names that
                 * allows enclosing the name in brackets.
                 */
                if (gly == ESCAPE_SPECIAL && *sz == 1 && **start != '-')
                        return ESCAPE_ERROR;
        } else {
                assert(*sz > 0);
                if ((size_t)*sz > strlen(*start))
                        return ESCAPE_ERROR;
                *end += *sz;
        }

        /* Run post-processors. */

        switch (gly) {
        case ESCAPE_FONT:
                gly = mandoc_font(*start, *sz);
                break;
        case ESCAPE_SPECIAL:
                if (**start == 'c') {
                        if (*sz < 6 || *sz > 7 ||
                            strncmp(*start, "char", 4) != 0 ||
                            (int)strspn(*start + 4, "0123456789") + 4 < *sz)
                                break;
                        c = 0;
                        for (i = 4; i < *sz; i++)
                                c = 10 * c + ((*start)[i] - '0');
                        if (c < 0x21 || (c > 0x7e && c < 0xa0) || c > 0xff)
                                break;
                        *start += 4;
                        *sz -= 4;
                        gly = ESCAPE_NUMBERED;
                        break;
                }

                /*
                 * Unicode escapes are defined in groff as \[u0000]
                 * to \[u10FFFF], where the contained value must be
                 * a valid Unicode codepoint.  Here, however, only
                 * check the length and range.
                 */
                if (**start != 'u' || *sz < 5 || *sz > 7)
                        break;
                if (*sz == 7 && ((*start)[1] != '1' || (*start)[2] != '0'))
                        break;
                if (*sz == 6 && (*start)[1] == '0')
                        break;
                if (*sz == 5 && (*start)[1] == 'D' &&
                    strchr("89ABCDEF", (*start)[2]) != NULL)
                        break;
                if ((int)strspn(*start + 1, "0123456789ABCDEFabcdef")
                    + 1 == *sz)
                        gly = ESCAPE_UNICODE;
                break;
        case ESCAPE_DEVICE:
                assert(*sz == 2 && (*start)[0] == '.' && (*start)[1] == 'T');
                break;
        default:
                break;
        }

        return gly;
}

static int
a2time(time_t *t, const char *fmt, const char *p)
{
        struct tm        tm;
        char            *pp;

        memset(&tm, 0, sizeof(struct tm));

        pp = NULL;
#if HAVE_STRPTIME
        pp = strptime(p, fmt, &tm);
#endif
        if (NULL != pp && '\0' == *pp) {
                *t = mktime(&tm);
                return 1;
        }

        return 0;
}

static char *
time2a(time_t t)
{
        struct tm       *tm;
        char            *buf, *p;
        size_t           ssz;
        int              isz;

        buf = NULL;
        tm = localtime(&t);
        if (tm == NULL)
                goto fail;

        /*
         * Reserve space:
         * up to 9 characters for the month (September) + blank
         * up to 2 characters for the day + comma + blank
         * 4 characters for the year and a terminating '\0'
         */

        p = buf = mandoc_malloc(10 + 4 + 4 + 1);

        if ((ssz = strftime(p, 10 + 1, "%B ", tm)) == 0)
                goto fail;
        p += (int)ssz;

        /*
         * The output format is just "%d" here, not "%2d" or "%02d".
         * That's also the reason why we can't just format the
         * date as a whole with "%B %e, %Y" or "%B %d, %Y".
         * Besides, the present approach is less prone to buffer
         * overflows, in case anybody should ever introduce the bug
         * of looking at LC_TIME.
         */

        isz = snprintf(p, 4 + 1, "%d, ", tm->tm_mday);
        if (isz < 0 || isz > 4)
                goto fail;
        p += isz;

        if (strftime(p, 4 + 1, "%Y", tm) == 0)
                goto fail;
        return buf;

fail:
        free(buf);
        return mandoc_strdup("");
}

char *
mandoc_normdate(struct roff_node *nch, struct roff_node *nbl)
{
        char            *cp;
        time_t           t;

        /* No date specified. */

        if (nch == NULL) {
                if (nbl == NULL)
                        mandoc_msg(MANDOCERR_DATE_MISSING, 0, 0, NULL);
                else
                        mandoc_msg(MANDOCERR_DATE_MISSING, nbl->line,
                            nbl->pos, "%s", roff_name[nbl->tok]);
                return mandoc_strdup("");
        }
        if (*nch->string == '\0') {
                mandoc_msg(MANDOCERR_DATE_MISSING, nch->line,
                    nch->pos, "%s", roff_name[nbl->tok]);
                return mandoc_strdup("");
        }
        if (strcmp(nch->string, "$" "Mdocdate$") == 0)
                return time2a(time(NULL));

        /* Valid mdoc(7) date format. */

        if (a2time(&t, "$" "Mdocdate: %b %d %Y $", nch->string) ||
            a2time(&t, "%b %d, %Y", nch->string)) {
                cp = time2a(t);
                if (t > time(NULL) + 86400)
                        mandoc_msg(MANDOCERR_DATE_FUTURE, nch->line,
                            nch->pos, "%s %s", roff_name[nbl->tok], cp);
                else if (*nch->string != '$' &&
                    strcmp(nch->string, cp) != 0)
                        mandoc_msg(MANDOCERR_DATE_NORM, nch->line,
                            nch->pos, "%s %s", roff_name[nbl->tok], cp);
                return cp;
        }

        /* In man(7), do not warn about the legacy format. */

        if (a2time(&t, "%Y-%m-%d", nch->string) == 0)
                mandoc_msg(MANDOCERR_DATE_BAD, nch->line, nch->pos,
                    "%s %s", roff_name[nbl->tok], nch->string);
        else if (t > time(NULL) + 86400)
                mandoc_msg(MANDOCERR_DATE_FUTURE, nch->line, nch->pos,
                    "%s %s", roff_name[nbl->tok], nch->string);
        else if (nbl->tok == MDOC_Dd)
                mandoc_msg(MANDOCERR_DATE_LEGACY, nch->line, nch->pos,
                    "Dd %s", nch->string);

        /* Use any non-mdoc(7) date verbatim. */

        return mandoc_strdup(nch->string);
}

int
mandoc_eos(const char *p, size_t sz)
{
        const char      *q;
        int              enclosed, found;

        if (0 == sz)
                return 0;

        /*
         * End-of-sentence recognition must include situations where
         * some symbols, such as `)', allow prior EOS punctuation to
         * propagate outward.
         */

        enclosed = found = 0;
        for (q = p + (int)sz - 1; q >= p; q--) {
                switch (*q) {
                case '\"':
                case '\'':
                case ']':
                case ')':
                        if (0 == found)
                                enclosed = 1;
                        break;
                case '.':
                case '!':
                case '?':
                        found = 1;
                        break;
                default:
                        return found &&
                            (!enclosed || isalnum((unsigned char)*q));
                }
        }

        return found && !enclosed;
}

/*
 * Convert a string to a long that may not be <0.
 * If the string is invalid, or is less than 0, return -1.
 */
int
mandoc_strntoi(const char *p, size_t sz, int base)
{
        char             buf[32];
        char            *ep;
        long             v;

        if (sz > 31)
                return -1;

        memcpy(buf, p, sz);
        buf[(int)sz] = '\0';

        errno = 0;
        v = strtol(buf, &ep, base);

        if (buf[0] == '\0' || *ep != '\0')
                return -1;

        if (v > INT_MAX)
                v = INT_MAX;
        if (v < INT_MIN)
                v = INT_MIN;

        return (int)v;
}