/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kevin Fall.
 *
 * 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/capsicum.h>
#include <sys/param.h>
#include <sys/stat.h>
#ifndef NO_UDOM_SUPPORT
#include <sys/socket.h>
#include <sys/un.h>
#include <netdb.h>
#endif

#include <capsicum_helpers.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>
#include <wctype.h>

#include <libcasper.h>
#include <casper/cap_fileargs.h>
#include <casper/cap_net.h>

static int bflag, eflag, lflag, nflag, sflag, tflag, vflag;
static int rval;
static const char *filename;
static fileargs_t *fa;

static void usage(void) __dead2;
static void scanfiles(char *argv[], int cooked);
#ifndef BOOTSTRAP_CAT
static void cook_cat(FILE *);
static ssize_t in_kernel_copy(int);
#endif
static void raw_cat(int);

#ifndef NO_UDOM_SUPPORT
static cap_channel_t *capnet;

static int udom_open(const char *path, int flags);
#endif

/*
 * Memory strategy threshold, in pages: if physmem is larger than this,
 * use a large buffer.
 */
#define PHYSPAGES_THRESHOLD (32 * 1024)

/* Maximum buffer size in bytes - do not allow it to grow larger than this. */
#define BUFSIZE_MAX (2 * 1024 * 1024)

/*
 * Small (default) buffer size in bytes. It's inefficient for this to be
 * smaller than MAXPHYS.
 */
#define BUFSIZE_SMALL (MAXPHYS)


/*
 * For the bootstrapped cat binary (needed for locked appending to METALOG), we
 * disable all flags except -l and -u to avoid non-portable function calls.
 * In the future we may instead want to write a small portable bootstrap tool
 * that locks the output file before writing to it. However, for now
 * bootstrapping cat without multibyte support is the simpler solution.
 */
#ifdef BOOTSTRAP_CAT
#define SUPPORTED_FLAGS "lu"
#else
#define SUPPORTED_FLAGS "belnstuv"
#endif

#ifndef NO_UDOM_SUPPORT
static void
init_casper_net(cap_channel_t *casper)
{
        cap_net_limit_t *limit;
        int familylimit;

        capnet = cap_service_open(casper, "system.net");
        if (capnet == NULL)
                err(EXIT_FAILURE, "unable to create network service");

        limit = cap_net_limit_init(capnet, CAPNET_NAME2ADDR |
            CAPNET_CONNECTDNS);
        if (limit == NULL)
                err(EXIT_FAILURE, "unable to create limits");

        familylimit = AF_LOCAL;
        cap_net_limit_name2addr_family(limit, &familylimit, 1);

        if (cap_net_limit(limit) != 0)
                err(EXIT_FAILURE, "unable to apply limits");
}
#endif

static void
init_casper(int argc, char *argv[])
{
        cap_channel_t *casper;
        cap_rights_t rights;

        casper = cap_init();
        if (casper == NULL)
                err(EXIT_FAILURE, "unable to create Casper");

        fa = fileargs_cinit(casper, argc, argv, O_RDONLY, 0,
            cap_rights_init(&rights, CAP_READ, CAP_FSTAT, CAP_FCNTL, CAP_SEEK),
            FA_OPEN | FA_REALPATH);
        if (fa == NULL)
                err(EXIT_FAILURE, "unable to create fileargs");

#ifndef NO_UDOM_SUPPORT
        init_casper_net(casper);
#endif

        cap_close(casper);
}

int
main(int argc, char *argv[])
{
        int ch;
        struct flock stdout_lock;

        setlocale(LC_CTYPE, "");

        while ((ch = getopt(argc, argv, SUPPORTED_FLAGS)) != -1)
                switch (ch) {
                case 'b':
                        bflag = nflag = 1;      /* -b implies -n */
                        break;
                case 'e':
                        eflag = vflag = 1;      /* -e implies -v */
                        break;
                case 'l':
                        lflag = 1;
                        break;
                case 'n':
                        nflag = 1;
                        break;
                case 's':
                        sflag = 1;
                        break;
                case 't':
                        tflag = vflag = 1;      /* -t implies -v */
                        break;
                case 'u':
                        setbuf(stdout, NULL);
                        break;
                case 'v':
                        vflag = 1;
                        break;
                default:
                        usage();
                }
        argv += optind;
        argc -= optind;

        if (lflag) {
                stdout_lock.l_len = 0;
                stdout_lock.l_start = 0;
                stdout_lock.l_type = F_WRLCK;
                stdout_lock.l_whence = SEEK_SET;
                if (fcntl(STDOUT_FILENO, F_SETLKW, &stdout_lock) != 0)
                        err(EXIT_FAILURE, "stdout");
        }

        init_casper(argc, argv);

        caph_cache_catpages();

        if (caph_enter_casper() != 0)
                err(EXIT_FAILURE, "capsicum");

        if (bflag || eflag || nflag || sflag || tflag || vflag)
                scanfiles(argv, 1);
        else
                scanfiles(argv, 0);
        if (fclose(stdout))
                err(1, "stdout");
        exit(rval);
        /* NOTREACHED */
}

static void
usage(void)
{

        fprintf(stderr, "usage: cat [-" SUPPORTED_FLAGS "] [file ...]\n");
        exit(1);
        /* NOTREACHED */
}

static void
scanfiles(char *argv[], int cooked __unused)
{
        int fd, i;
        char *path;
#ifndef BOOTSTRAP_CAT
        FILE *fp;
#endif

        i = 0;
        fd = -1;
        while ((path = argv[i]) != NULL || i == 0) {
                if (path == NULL || strcmp(path, "-") == 0) {
                        filename = "stdin";
                        fd = STDIN_FILENO;
                } else {
                        filename = path;
                        fd = fileargs_open(fa, path);
#ifndef NO_UDOM_SUPPORT
                        if (fd < 0 && errno == EOPNOTSUPP)
                                fd = udom_open(path, O_RDONLY);
#endif
                }
                if (fd < 0) {
                        warn("%s", path);
                        rval = 1;
#ifndef BOOTSTRAP_CAT
                } else if (cooked) {
                        if (fd == STDIN_FILENO)
                                cook_cat(stdin);
                        else {
                                fp = fdopen(fd, "r");
                                cook_cat(fp);
                                fclose(fp);
                        }
#endif
                } else {
#ifndef BOOTSTRAP_CAT
                        if (in_kernel_copy(fd) != 0) {
                                if (errno == EINVAL || errno == EBADF ||
                                    errno == EISDIR)
                                        raw_cat(fd);
                                else
                                        err(1, "%s", filename);
                        }
#else
                        raw_cat(fd);
#endif
                        if (fd != STDIN_FILENO)
                                close(fd);
                }
                if (path == NULL)
                        break;
                ++i;
        }
}

#ifndef BOOTSTRAP_CAT
static void
cook_cat(FILE *fp)
{
        int ch, gobble, line, prev;
        wint_t wch;

        /* Reset EOF condition on stdin. */
        if (fp == stdin && feof(stdin))
                clearerr(stdin);

        line = gobble = 0;
        for (prev = '\n'; (ch = getc(fp)) != EOF; prev = ch) {
                if (prev == '\n') {
                        if (sflag) {
                                if (ch == '\n') {
                                        if (gobble)
                                                continue;
                                        gobble = 1;
                                } else
                                        gobble = 0;
                        }
                        if (nflag) {
                                if (!bflag || ch != '\n') {
                                        (void)fprintf(stdout, "%6d\t", ++line);
                                        if (ferror(stdout))
                                                break;
                                } else if (eflag) {
                                        (void)fprintf(stdout, "%6s\t", "");
                                        if (ferror(stdout))
                                                break;
                                }
                        }
                }
                if (ch == '\n') {
                        if (eflag && putchar('$') == EOF)
                                break;
                } else if (ch == '\t') {
                        if (tflag) {
                                if (putchar('^') == EOF || putchar('I') == EOF)
                                        break;
                                continue;
                        }
                } else if (vflag) {
                        (void)ungetc(ch, fp);
                        /*
                         * Our getwc(3) doesn't change file position
                         * on error.
                         */
                        if ((wch = getwc(fp)) == WEOF) {
                                if (ferror(fp) && errno == EILSEQ) {
                                        clearerr(fp);
                                        /* Resync attempt. */
                                        memset(&fp->_mbstate, 0, sizeof(mbstate_t));
                                        if ((ch = getc(fp)) == EOF)
                                                break;
                                        wch = ch;
                                        goto ilseq;
                                } else
                                        break;
                        }
                        if (!iswascii(wch) && !iswprint(wch)) {
ilseq:
                                if (putchar('M') == EOF || putchar('-') == EOF)
                                        break;
                                wch = toascii(wch);
                        }
                        if (iswcntrl(wch)) {
                                ch = toascii(wch);
                                ch = (ch == '\177') ? '?' : (ch | 0100);
                                if (putchar('^') == EOF || putchar(ch) == EOF)
                                        break;
                                continue;
                        }
                        if (putwchar(wch) == WEOF)
                                break;
                        ch = -1;
                        continue;
                }
                if (putchar(ch) == EOF)
                        break;
        }
        if (ferror(fp)) {
                warn("%s", filename);
                rval = 1;
                clearerr(fp);
        }
        if (ferror(stdout))
                err(1, "stdout");
}

static ssize_t
in_kernel_copy(int rfd)
{
        int wfd;
        ssize_t ret;

        wfd = fileno(stdout);
        ret = 1;

        while (ret > 0)
                ret = copy_file_range(rfd, NULL, wfd, NULL, SSIZE_MAX, 0);

        return (ret);
}
#endif /* BOOTSTRAP_CAT */

static void
raw_cat(int rfd)
{
        long pagesize;
        int off, wfd;
        ssize_t nr, nw;
        static size_t bsize;
        static char *buf = NULL;
        struct stat sbuf;

        wfd = fileno(stdout);
        if (buf == NULL) {
                if (fstat(wfd, &sbuf))
                        err(1, "stdout");
                if (S_ISREG(sbuf.st_mode)) {
                        /* If there's plenty of RAM, use a large copy buffer */
                        if (sysconf(_SC_PHYS_PAGES) > PHYSPAGES_THRESHOLD)
                                bsize = MIN(BUFSIZE_MAX, MAXPHYS * 8);
                        else
                                bsize = BUFSIZE_SMALL;
                } else {
                        bsize = sbuf.st_blksize;
                        pagesize = sysconf(_SC_PAGESIZE);
                        if (pagesize > 0)
                                bsize = MAX(bsize, (size_t)pagesize);
                }
                if ((buf = malloc(bsize)) == NULL)
                        err(1, "malloc() failure of IO buffer");
        }
        while ((nr = read(rfd, buf, bsize)) > 0)
                for (off = 0; nr; nr -= nw, off += nw)
                        if ((nw = write(wfd, buf + off, (size_t)nr)) < 0)
                                err(1, "stdout");
        if (nr < 0) {
                warn("%s", filename);
                rval = 1;
        }
}

#ifndef NO_UDOM_SUPPORT

static int
udom_open(const char *path, int flags)
{
        struct addrinfo hints, *res, *res0;
        char rpath[PATH_MAX];
        int error, fd, serrno;
        cap_rights_t rights;

        /*
         * Construct the unix domain socket address and attempt to connect.
         */
        bzero(&hints, sizeof(hints));
        hints.ai_family = AF_LOCAL;

        if (fileargs_realpath(fa, path, rpath) == NULL)
                return (-1);

        error = cap_getaddrinfo(capnet, rpath, NULL, &hints, &res0);
        if (error) {
                warn("%s", gai_strerror(error));
                errno = EINVAL;
                return (-1);
        }
        cap_rights_init(&rights, CAP_CONNECT, CAP_READ, CAP_WRITE,
            CAP_SHUTDOWN, CAP_FSTAT, CAP_FCNTL);

        /* Default error if something goes wrong. */
        serrno = EINVAL;

        for (res = res0; res != NULL; res = res->ai_next) {
                fd = socket(res->ai_family, res->ai_socktype,
                    res->ai_protocol);
                if (fd < 0) {
                        serrno = errno;
                        freeaddrinfo(res0);
                        errno = serrno;
                        return (-1);
                }
                if (caph_rights_limit(fd, &rights) != 0) {
                        serrno = errno;
                        close(fd);
                        freeaddrinfo(res0);
                        errno = serrno;
                        return (-1);
                }
                error = cap_connect(capnet, fd, res->ai_addr, res->ai_addrlen);
                if (error == 0)
                        break;
                else {
                        serrno = errno;
                        close(fd);
                }
        }
        freeaddrinfo(res0);

        if (res == NULL) {
                errno = serrno;
                return (-1);
        }

        /*
         * handle the open flags by shutting down appropriate directions
         */

        switch (flags & O_ACCMODE) {
        case O_RDONLY:
                cap_rights_clear(&rights, CAP_WRITE);
                if (shutdown(fd, SHUT_WR) != 0)
                        warn(NULL);
                break;
        case O_WRONLY:
                cap_rights_clear(&rights, CAP_READ);
                if (shutdown(fd, SHUT_RD) != 0)
                        warn(NULL);
                break;
        default:
                break;
        }

        cap_rights_clear(&rights, CAP_CONNECT, CAP_SHUTDOWN);
        if (caph_rights_limit(fd, &rights) != 0) {
                serrno = errno;
                close(fd);
                errno = serrno;
                return (-1);
        }
        return (fd);
}

#endif