/*      $OpenBSD: ktrace.c,v 1.40 2023/03/08 04:43:11 guenther Exp $    */
/*      $NetBSD: ktrace.c,v 1.4 1995/08/31 23:01:44 jtc Exp $   */

/*-
 * Copyright (c) 1988, 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.
 */

#include <sys/types.h>
#include <sys/signal.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <sys/ktrace.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include "ktrace.h"
#include "extern.h"

extern char *__progname;

static int rpid(const char *);
static void no_ktrace(int);
static void usage(void);

int     is_ltrace;

int
main(int argc, char *argv[])
{
        enum { NOTSET, CLEAR, CLEARALL } clear;
        int append, ch, fd, inherit, ops, pidset, trpoints;
        pid_t pid;
        char *tracefile, *tracespec;
        mode_t omask;
        struct stat sb;

        is_ltrace = strcmp(__progname, "ltrace") == 0;

        clear = NOTSET;
        append = ops = pidset = inherit = pid = 0;
        trpoints = is_ltrace ? KTRFAC_USER : DEF_POINTS;
        tracefile = DEF_TRACEFILE;
        tracespec = NULL;

        if (is_ltrace) {
                while ((ch = getopt(argc, argv, "af:it:u:")) != -1)
                        switch ((char)ch) {
                        case 'a':
                                append = 1;
                                break;
                        case 'f':
                                tracefile = optarg;
                                break;
                        case 'i':
                                inherit = 1;
                                break;
                        case 't':
                                trpoints = getpoints(optarg, KTRFAC_USER);
                                if (trpoints < 0) {
                                        warnx("unknown facility in %s", optarg);
                                        usage();
                                }
                                break;
                        case 'u':
                                tracespec = optarg;
                                break;
                        default:
                                usage();
                        }
        } else {
                while ((ch = getopt(argc, argv, "aBCcdf:g:ip:t:T")) != -1)
                        switch ((char)ch) {
                        case 'a':
                                append = 1;
                                break;
                        case 'B':
                                putenv("LD_BIND_NOW=");
                                break;
                        case 'C':
                                clear = CLEARALL;
                                tracefile = NULL;
                                pidset = 1;
                                break;
                        case 'c':
                                clear = CLEAR;
                                break;
                        case 'd':
                                ops |= KTRFLAG_DESCEND;
                                break;
                        case 'f':
                                tracefile = optarg;
                                break;
                        case 'g':
                                pid = -rpid(optarg);
                                pidset = 1;
                                break;
                        case 'i':
                                inherit = 1;
                                break;
                        case 'p':
                                pid = rpid(optarg);
                                pidset = 1;
                                break;
                        case 't':
                                trpoints = getpoints(optarg, DEF_POINTS);
                                if (trpoints < 0) {
                                        warnx("unknown facility in %s", optarg);
                                        usage();
                                }
                                break;
                        case 'T':
                                putenv("LIBC_NOUSERTC=");
                                break;
                        default:
                                usage();
                        }
        }

        argv += optind;
        argc -= optind;
        
        if ((pidset && *argv) || (!pidset && !*argv && clear != CLEAR))
                usage();

        if (inherit)
                trpoints |= KTRFAC_INHERIT;

        (void)signal(SIGSYS, no_ktrace);
        if (clear != NOTSET) {
                if (clear == CLEARALL) {
                        ops = KTROP_CLEAR | KTRFLAG_DESCEND;
                        trpoints = ALL_POINTS;
                        pid = 1;
                } else
                        ops |= pid ? KTROP_CLEAR : KTROP_CLEARFILE;

                if (ktrace(tracefile, ops, trpoints, pid) == -1) {
                        if (errno == ESRCH)
                                err(1, "%d", pid);
                        err(1, "%s", tracefile);
                }
                exit(0);
        }

        omask = umask(S_IRWXG|S_IRWXO);
        if (append) {
                if ((fd = open(tracefile, O_CREAT | O_WRONLY, DEFFILEMODE)) == -1)
                        err(1, "%s", tracefile);
                if (fstat(fd, &sb) != 0 || sb.st_uid != getuid())
                        errx(1, "Refuse to append to %s: not owned by you.",
                            tracefile);
        } else {
                if (unlink(tracefile) == -1 && errno != ENOENT)
                        err(1, "unlink %s", tracefile);
                if ((fd = open(tracefile, O_CREAT | O_EXCL | O_WRONLY,
                    DEFFILEMODE)) == -1)
                        err(1, "%s", tracefile);
        }
        (void)umask(omask);
        (void)close(fd);

        if (*argv) { 
                if (is_ltrace) {
                        if (setenv("LD_TRACE_PLT", inherit ? "i" : "", 1) < 0)
                                err(1, "setenv(LD_TRACE_PLT)");
                        if (tracespec &&
                            setenv("LD_TRACE_PLTSPEC", tracespec, 1) < 0)
                                err(1, "setenv(LD_TRACE_PLTSPEC)");
                }
                if (ktrace(tracefile, ops, trpoints, getpid()) == -1)
                        err(1, "%s", tracefile);
                execvp(argv[0], &argv[0]);
                err(1, "exec of '%s' failed", argv[0]);
        }
        else if (ktrace(tracefile, ops, trpoints, pid) == -1) {
                if (errno == ESRCH)
                        err(1, "%d", pid);
                err(1, "%s", tracefile);
        }
        exit(0);
}

static int
rpid(const char *p)
{
        const char *errstr;
        static int first;
        pid_t pid;

        if (first++) {
                warnx("only one -g or -p flag is permitted.");
                usage();
        }
        if (!*p) {
                warnx("illegal process id.");
                usage();
        }
        pid = strtonum(p, 1, INT_MAX, &errstr);
        if (errstr) {
                warnx("illegal process id: %s", errstr);
                usage();
        }
        return pid;
}

static void
usage(void)
{
        if (is_ltrace)
                fprintf(stderr, "usage: %s [-ai] [-f trfile] [-t trstr]"
                    " [-u trspec] command\n",
                    __progname);
        else
                fprintf(stderr, "usage: %s [-aCcdi] [-f trfile] [-g pgid]"
                    " [-p pid] [-t trstr]\n"
                    "       %s [-aBdiT] [-f trfile] [-t trstr] command\n",
                    __progname, __progname);
        exit(1);
}

static void
no_ktrace(int signo)
{
        dprintf(STDERR_FILENO,
"error:\tktrace() system call not supported in the running kernel\n\tre-compile kernel with 'option KTRACE'\n");
        _exit(1);
}