/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 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.
 */

/*
 *      lam - laminate files
 *      Author:  John Kunze, UCB
 */

#include <sys/capsicum.h>

#include <capsicum_helpers.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

#define MAXOFILES       20
#define BIGBUFSIZ       5 * BUFSIZ

static struct openfile {        /* open file structure */
        FILE    *fp;            /* file pointer */
        short   eof;            /* eof flag */
        short   pad;            /* pad flag for missing columns */
        char    eol;            /* end of line character */
        const char *sepstring;  /* string to print before each line */
        const char *format;     /* printf(3) style string spec. */
}       input[MAXOFILES];

static int      morefiles;      /* set by getargs(), changed by gatherline() */
static int      nofinalnl;      /* normally append \n to each output line */
static char     line[BIGBUFSIZ];
static char     *linep;

static char    *gatherline(struct openfile *);
static void     getargs(char *[]);
static char    *pad(struct openfile *);
static void     usage(void);

int
main(int argc, char *argv[])
{
        struct  openfile *ip;

        if (argc == 1)
                usage();
        if (caph_limit_stdio() == -1)
                err(1, "unable to limit stdio");
        getargs(argv);
        if (!morefiles)
                usage();

        /*
         * Cache NLS data, for strerror, for err(3), before entering capability
         * mode.
         */
        caph_cache_catpages();
        if (caph_enter() < 0)
                err(1, "unable to enter capability mode");

        for (;;) {
                linep = line;
                for (ip = input; ip->fp != NULL; ip++)
                        linep = gatherline(ip);
                if (!morefiles)
                        exit(0);
                fputs(line, stdout);
                fputs(ip->sepstring, stdout);
                if (!nofinalnl)
                        putchar('\n');
        }
}

static void
getargs(char *av[])
{
        struct  openfile *ip = input;
        char *p, *c;
        static char fmtbuf[BUFSIZ];
        char *fmtp = fmtbuf;
        int P, S, F, T;
        cap_rights_t rights_ro;

        cap_rights_init(&rights_ro, CAP_READ, CAP_FSTAT);
        P = S = F = T = 0;              /* capitalized options */
        while ((p = *++av) != NULL) {
                if (*p != '-' || !p[1]) {
                        if (++morefiles >= MAXOFILES)
                                errx(1, "too many input files");
                        if (*p == '-')
                                ip->fp = stdin;
                        else if ((ip->fp = fopen(p, "r")) == NULL) {
                                err(1, "%s", p);
                        }
                        if (caph_rights_limit(fileno(ip->fp), &rights_ro) < 0)
                                err(1, "unable to limit rights on: %s", p);
                        ip->pad = P;
                        if (!ip->sepstring)
                                ip->sepstring = (S ? (ip-1)->sepstring : "");
                        if (!ip->format)
                                ip->format = ((P || F) ? (ip-1)->format : "%s");
                        if (!ip->eol)
                                ip->eol = (T ? (ip-1)->eol : '\n');
                        ip++;
                        continue;
                }
                c = ++p;
                switch (tolower((unsigned char)*c)) {
                case 's':
                        if (*++p || (p = *++av))
                                ip->sepstring = p;
                        else
                                usage();
                        S = (*c == 'S' ? 1 : 0);
                        break;
                case 't':
                        if (*++p || (p = *++av))
                                ip->eol = *p;
                        else
                                usage();
                        T = (*c == 'T' ? 1 : 0);
                        nofinalnl = 1;
                        break;
                case 'p':
                        ip->pad = 1;
                        P = (*c == 'P' ? 1 : 0);
                        /* FALLTHROUGH */
                case 'f':
                        F = (*c == 'F' ? 1 : 0);
                        if (*++p || (p = *++av)) {
                                fmtp += strlen(fmtp) + 1;
                                if (fmtp >= fmtbuf + sizeof(fmtbuf))
                                        errx(1, "no more format space");
                                /* restrict format string to only valid width formatters */
                                if (strspn(p, "-.0123456789") != strlen(p))
                                        errx(1, "invalid format string `%s'", p);
                                if (snprintf(fmtp, fmtbuf + sizeof(fmtbuf) - fmtp, "%%%ss", p)
                                    >= fmtbuf + sizeof(fmtbuf) - fmtp)
                                        errx(1, "no more format space");
                                ip->format = fmtp;
                        }
                        else
                                usage();
                        break;
                default:
                        usage();
                }
        }
        ip->fp = NULL;
        if (!ip->sepstring)
                ip->sepstring = "";
}

static char *
pad(struct openfile *ip)
{
        char *lp = linep;

        strlcpy(lp, ip->sepstring, line + sizeof(line) - lp);
        lp += strlen(lp);
        if (ip->pad) {
                snprintf(lp, line + sizeof(line) - lp, ip->format, "");
                lp += strlen(lp);
        }
        return (lp);
}

static char *
gatherline(struct openfile *ip)
{
        char s[BUFSIZ];
        int c;
        char *p;
        char *lp = linep;
        char *end = s + sizeof(s) - 1;

        if (ip->eof)
                return (pad(ip));
        for (p = s; (c = fgetc(ip->fp)) != EOF && p < end; p++)
                if ((*p = c) == ip->eol)
                        break;
        *p = '\0';
        if (c == EOF) {
                ip->eof = 1;
                if (ferror(ip->fp))
                        err(EX_IOERR, NULL);
                morefiles--;
                return (pad(ip));
        }
        strlcpy(lp, ip->sepstring, line + sizeof(line) - lp);
        lp += strlen(lp);
        snprintf(lp, line + sizeof(line) - lp, ip->format, s);
        lp += strlen(lp);
        return (lp);
}

static void
usage(void)
{
        fprintf(stderr, "%s\n%s\n",
"usage: lam [ -f min.max ] [ -s sepstring ] [ -t c ] file ...",
"       lam [ -p min.max ] [ -s sepstring ] [ -t c ] file ...");
        exit(1);
}