/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2002 Jake Burkholder
 * Copyright (c) 2004 Robert Watson
 * 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.
 */

#include <sys/types.h>
#include <sys/capsicum.h>
#include <sys/ktr.h>
#include <sys/mman.h>
#include <sys/stat.h>

#include <capsicum_helpers.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <kvm.h>
#include <limits.h>
#include <nlist.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define SBUFLEN 128
#define USAGE \
        "usage: ktrdump [-cflqrtH] [-i ktrfile] [-M core] [-N system] [-o outfile]\n"

static void usage(void) __dead2;

static struct nlist nl[] = {
        { .n_name = "_ktr_version" },
        { .n_name = "_ktr_entries" },
        { .n_name = "_ktr_idx" },
        { .n_name = "_ktr_buf" },
        { .n_name = NULL }
};

static int cflag;
static int fflag;
static int lflag;
static int Mflag;
static int Nflag;
static int qflag;
static int rflag;
static int tflag;
static int iflag;
static int hflag;

static char corefile[PATH_MAX];
static char execfile[PATH_MAX];
static char outfile[PATH_MAX] = "stdout";

static char desc[SBUFLEN];
static char errbuf[_POSIX2_LINE_MAX];
static char fbuf[PATH_MAX];
static char obuf[PATH_MAX];
static char sbuf[KTR_PARMS][SBUFLEN];

/*
 * Reads the ktr trace buffer from kernel memory and prints the trace entries.
 */
int
main(int ac, char **av)
{
        u_long parms[KTR_PARMS];
        struct ktr_entry *buf;
        uintmax_t tlast, tnow;
        unsigned long bufptr;
        cap_rights_t rights;
        struct stat sb;
        kvm_t *kd;
        FILE *out;
        char *p;
        int version;
        int entries;
        int count;
        int index, index2;
        int parm;
        int in;
        int c;
        int i = 0;

        /*
         * Parse commandline arguments.
         */
        out = stdout;
        while ((c = getopt(ac, av, "cflqrtHe:i:m:M:N:o:")) != -1)
                switch (c) {
                case 'c':
                        cflag = 1;
                        break;
                case 'N':
                case 'e':
                        if (strlcpy(execfile, optarg, sizeof(execfile))
                            >= sizeof(execfile))
                                errx(1, "%s: File name too long", optarg);
                        Nflag = 1;
                        break;
                case 'f':
                        fflag = 1;
                        break;
                case 'i':
                        iflag = 1;
                        if ((in = open(optarg, O_RDONLY)) == -1)
                                err(1, "%s", optarg);
                        cap_rights_init(&rights, CAP_FSTAT, CAP_MMAP_R);
                        if (caph_rights_limit(in, &rights) < 0)
                                err(1, "unable to limit rights for %s",
                                    optarg);
                        break;
                case 'l':
                        lflag = 1;
                        break;
                case 'M':
                case 'm':
                        if (strlcpy(corefile, optarg, sizeof(corefile))
                            >= sizeof(corefile))
                                errx(1, "%s: File name too long", optarg);
                        Mflag = 1;
                        break;
                case 'o':
                        if ((out = fopen(optarg, "w")) == NULL)
                                err(1, "%s", optarg);
                        strlcpy(outfile, optarg, sizeof(outfile));
                        break;
                case 'q':
                        qflag++;
                        break;
                case 'r':
                        rflag = 1;
                        break;
                case 't':
                        tflag = 1;
                        break;
                case 'H':
                        hflag = 1;
                        break;
                case '?':
                default:
                        usage();
                }
        ac -= optind;
        av += optind;
        if (ac != 0)
                usage();

        if (caph_limit_stream(fileno(out), CAPH_WRITE) < 0)
                err(1, "unable to limit rights for %s", outfile);
        if (caph_limit_stderr() < 0)
                err(1, "unable to limit rights for stderr");

        /*
         * Open our execfile and corefile, resolve needed symbols and read in
         * the trace buffer.
         */
        if ((kd = kvm_openfiles(Nflag ? execfile : NULL,
            Mflag ? corefile : NULL, NULL, O_RDONLY, errbuf)) == NULL)
                errx(1, "%s", errbuf);

        /*
         * Cache NLS data, for strerror, for err(3), before entering capability
         * mode.
         */
        caph_cache_catpages();

        count = kvm_nlist(kd, nl);
        if (count == -1)
                errx(1, "%s", kvm_geterr(kd));
        if (count > 0)
                errx(1, "failed to resolve ktr symbols");
        if (kvm_read(kd, nl[0].n_value, &version, sizeof(version)) == -1)
                errx(1, "%s", kvm_geterr(kd));
        if (version != KTR_VERSION)
                errx(1, "ktr version mismatch");

        /*
         * Enter Capsicum sandbox.
         *
         * kvm_nlist() above uses kldsym(2) for native kernels, and that isn't
         * allowed in the sandbox.
         */
        if (caph_enter() < 0)
                err(1, "unable to enter capability mode");

        if (iflag) {
                if (fstat(in, &sb) == -1)
                        errx(1, "stat");
                entries = sb.st_size / sizeof(*buf);
                index = 0;
                buf = mmap(NULL, sb.st_size, PROT_READ, MAP_SHARED, in, 0);
                if (buf == MAP_FAILED)
                        errx(1, "mmap");
        } else {
                if (kvm_read(kd, nl[1].n_value, &entries, sizeof(entries))
                    == -1)
                        errx(1, "%s", kvm_geterr(kd));
                if ((buf = malloc(sizeof(*buf) * entries)) == NULL)
                        err(1, NULL);
                if (kvm_read(kd, nl[2].n_value, &index, sizeof(index)) == -1 ||
                    kvm_read(kd, nl[3].n_value, &bufptr,
                    sizeof(bufptr)) == -1 ||
                    kvm_read(kd, bufptr, buf, sizeof(*buf) * entries) == -1 ||
                    kvm_read(kd, nl[2].n_value, &index2, sizeof(index2)) == -1)
                        errx(1, "%s", kvm_geterr(kd));
        }

        /*
         * Print a nice header.
         */
        if (!qflag) {
                fprintf(out, "%-6s ", "index");
                if (cflag)
                        fprintf(out, "%-3s ", "cpu");
                if (tflag)
                        fprintf(out, "%-16s ", "timestamp");
                if (fflag)
                        fprintf(out, "%-40s ", "file and line");
                if (hflag)
                        fprintf(out, "%-18s ", "tid");
                fprintf(out, "%s", "trace");
                fprintf(out, "\n");

                fprintf(out, "------ ");
                if (cflag)
                        fprintf(out, "--- ");
                if (tflag)
                        fprintf(out, "---------------- ");
                if (fflag)
                        fprintf(out,
                            "---------------------------------------- ");
                if (hflag)
                        fprintf(out, "------------------ ");
                fprintf(out, "----- ");
                fprintf(out, "\n");
        }

        tlast = UINTPTR_MAX;
        /*
         * Now tear through the trace buffer.
         *
         * In "live" mode, find the oldest entry (first non-NULL entry
         * after index2) and walk forward.  Otherwise, start with the
         * most recent entry and walk backwards.
         */
        if (!iflag) {
                if (lflag) {
                        i = index2 + 1 % entries;
                        while (buf[i].ktr_desc == NULL && i != index) {
                                i++;
                                if (i == entries)
                                        i = 0;
                        }
                } else {
                        i = index - 1;
                        if (i < 0)
                                i = entries - 1;
                }
        }
dump_entries:
        for (;;) {
                if (buf[i].ktr_desc == NULL)
                        break;
                if (kvm_read(kd, (u_long)buf[i].ktr_desc, desc,
                    sizeof(desc)) == -1)
                        errx(1, "%s", kvm_geterr(kd));
                desc[sizeof(desc) - 1] = '\0';
                parm = 0;
                for (p = desc; (c = *p++) != '\0';) {
                        if (c != '%')
                                continue;
next:                   if ((c = *p++) == '\0')
                                break;
                        if (c == '%')
                                continue;
                        if (parm == KTR_PARMS)
                                errx(1, "too many parameters in \"%s\"", desc);
                        switch (c) {
                        case '0': case '1': case '2': case '3': case '4':
                        case '5': case '6': case '7': case '8': case '9':
                        case '#': case '-': case ' ': case '+': case '\'':
                        case 'h': case 'l': case 'j': case 't': case 'z':
                        case 'q': case 'L': case '.':
                                goto next;
                        case 's':
                                if (kvm_read(kd, (u_long)buf[i].ktr_parms[parm],
                                    sbuf[parm], sizeof(sbuf[parm])) == -1)
                                        strcpy(sbuf[parm], "(null)");
                                sbuf[parm][sizeof(sbuf[0]) - 1] = '\0';
                                parms[parm] = (u_long)sbuf[parm];
                                parm++;
                                break;
                        default:
                                parms[parm] = buf[i].ktr_parms[parm];
                                parm++;
                                break;
                        }
                }
                fprintf(out, "%6d ", i);
                if (cflag)
                        fprintf(out, "%3d ", buf[i].ktr_cpu);
                if (tflag) {
                        tnow = (uintmax_t)buf[i].ktr_timestamp;
                        if (rflag) {
                                if (tlast == UINTPTR_MAX)
                                        tlast = tnow;
                                fprintf(out, "%16ju ", !iflag ? tlast - tnow :
                                    tnow - tlast);
                                tlast = tnow;
                        } else
                                fprintf(out, "%16ju ", tnow);
                }
                if (fflag) {
                        if (kvm_read(kd, (u_long)buf[i].ktr_file, fbuf,
                            sizeof(fbuf)) == -1)
                                strcpy(fbuf, "(null)");
                        snprintf(obuf, sizeof(obuf), "%s:%d", fbuf,
                            buf[i].ktr_line);
                        fprintf(out, "%-40s ", obuf);
                }
                if (hflag)
                        fprintf(out, "%p ", buf[i].ktr_thread);
                fprintf(out, desc, parms[0], parms[1], parms[2], parms[3],
                    parms[4], parms[5]);
                fprintf(out, "\n");
                if (!iflag) {
                        /*
                         * 'index' and 'index2' are the values of 'ktr_idx'
                         * before and after the KTR buffer was copied into
                         * 'buf'. Since the KTR entries between 'index' and
                         * 'index2' were in flux while the KTR buffer was
                         * being copied to userspace we don't dump them.
                         */
                        if (lflag) {
                                if (++i == entries)
                                        i = 0;
                                if (i == index)
                                        break;
                        } else {
                                if (i == index2)
                                        break;
                                if (--i < 0)
                                        i = entries - 1;
                        }
                } else {
                        if (++i == entries)
                                break;
                }
        }

        /*
         * In "live" mode, poll 'ktr_idx' periodically and dump any
         * new entries since our last pass through the ring.
         */
        if (lflag && !iflag) {
                while (index == index2) {
                        usleep(50 * 1000);
                        if (kvm_read(kd, nl[2].n_value, &index2,
                            sizeof(index2)) == -1)
                                errx(1, "%s", kvm_geterr(kd));
                }
                i = index;
                index = index2;
                if (kvm_read(kd, bufptr, buf, sizeof(*buf) * entries) == -1 ||
                    kvm_read(kd, nl[2].n_value, &index2, sizeof(index2)) == -1)
                        errx(1, "%s", kvm_geterr(kd));
                goto dump_entries;
        }

        return (0);
}

static void
usage(void)
{

        fprintf(stderr, USAGE);
        exit(1);
}