root/usr.bin/truss/main.c
/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright 1997 Sean Eric Fagan
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Sean Eric Fagan
 * 4. Neither the name of the author may be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * 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/cdefs.h>
/*
 * The main module for truss.  Surprisingly simple, but, then, the other
 * files handle the bulk of the work.  And, of course, the kernel has to
 * do a lot of the work :).
 */

#include <sys/ptrace.h>

#include <err.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <sysdecode.h>
#include <time.h>
#include <unistd.h>

#include "truss.h"
#include "extern.h"
#include "syscall.h"

static __dead2 void
usage(void)
{
        fprintf(stderr, "%s\n%s\n",
            "usage: truss [-cfaedDHS] [-o file] [-s strsize] -p pid",
            "       truss [-cfaedDHS] [-o file] [-s strsize] command [args]");
        exit(1);
}

int
main(int ac, char **av)
{
        struct sigaction sa;
        struct trussinfo *trussinfo;
        char *fname;
        char **command;
        const char *errstr;
        pid_t pid;
        int c;

        fname = NULL;

        /* Initialize the trussinfo struct */
        trussinfo = (struct trussinfo *)calloc(1, sizeof(struct trussinfo));
        if (trussinfo == NULL)
                errx(1, "calloc() failed");

        pid = 0;
        trussinfo->outfile = stderr;
        trussinfo->strsize = 32;
        trussinfo->curthread = NULL;
        LIST_INIT(&trussinfo->proclist);
        while ((c = getopt(ac, av, "p:o:facedDs:SH")) != -1) {
                switch (c) {
                case 'p':       /* specified pid */
                        pid = atoi(optarg);
                        /* make sure i don't trace me */
                        if (pid == getpid()) {
                                errx(2, "attempt to grab self.");
                        }
                        break;
                case 'f': /* Follow fork()'s */
                        trussinfo->flags |= FOLLOWFORKS;
                        break;
                case 'a': /* Print execve() argument strings. */
                        trussinfo->flags |= EXECVEARGS;
                        break;
                case 'c': /* Count number of system calls and time. */
                        trussinfo->flags |= (COUNTONLY | NOSIGS);
                        break;
                case 'e': /* Print execve() environment strings. */
                        trussinfo->flags |= EXECVEENVS;
                        break;
                case 'd': /* Absolute timestamps */
                        trussinfo->flags |= ABSOLUTETIMESTAMPS;
                        break;
                case 'D': /* Relative timestamps */
                        trussinfo->flags |= RELATIVETIMESTAMPS;
                        break;
                case 'o':       /* Specified output file */
                        fname = optarg;
                        break;
                case 's':       /* Specified string size */
                        trussinfo->strsize = (int)strtonum(optarg, 0, INT_MAX,
                            &errstr);
                        if (errstr)
                                errx(1, "maximum string size is %s: %s", errstr, optarg);
                        break;
                case 'S':       /* Don't trace signals */
                        trussinfo->flags |= NOSIGS;
                        break;
                case 'H':
                        trussinfo->flags |= DISPLAYTIDS;
                        break;
                default:
                        usage();
                }
        }

        ac -= optind; av += optind;
        if ((pid == 0 && ac == 0) ||
            (pid != 0 && ac != 0))
                usage();

        if (fname != NULL) { /* Use output file */
                /*
                 * Set close-on-exec ('e'), so that the output file is not
                 * shared with the traced process.
                 */
                if ((trussinfo->outfile = fopen(fname, "we")) == NULL)
                        err(1, "cannot open %s", fname);
        }

        /*
         * If truss starts the process itself, it will ignore some signals --
         * they should be passed off to the process, which may or may not
         * exit.  If, however, we are examining an already-running process,
         * then we restore the event mask on these same signals.
         */
        if (pid == 0) {
                /* Start a command ourselves */
                command = av;
                setup_and_wait(trussinfo, command);
                signal(SIGINT, SIG_IGN);
                signal(SIGTERM, SIG_IGN);
                signal(SIGQUIT, SIG_IGN);
        } else {
                sa.sa_handler = restore_proc;
                sa.sa_flags = 0;
                sigemptyset(&sa.sa_mask);
                sigaction(SIGINT, &sa, NULL);
                sigaction(SIGQUIT, &sa, NULL);
                sigaction(SIGTERM, &sa, NULL);
                start_tracing(trussinfo, pid);
        }

        /*
         * At this point, if we started the process, it is stopped waiting to
         * be woken up, either in exit() or in execve().
         */
        if (LIST_FIRST(&trussinfo->proclist)->abi == NULL) {
                /*
                 * If we are not able to handle this ABI, detach from the
                 * process and exit.  If we just created a new process to
                 * run a command, kill the new process rather than letting
                 * it run untraced.
                 */
                if (pid == 0)
                        kill(LIST_FIRST(&trussinfo->proclist)->pid, SIGKILL);
                ptrace(PT_DETACH, LIST_FIRST(&trussinfo->proclist)->pid, NULL,
                    0);
                return (1);
        }
        ptrace(PT_SYSCALL, LIST_FIRST(&trussinfo->proclist)->pid, (caddr_t)1,
            0);

        /*
         * At this point, it's a simple loop, waiting for the process to
         * stop, finding out why, printing out why, and then continuing it.
         * All of the grunt work is done in the support routines.
         */
        clock_gettime(CLOCK_REALTIME, &trussinfo->start_time);

        eventloop(trussinfo);

        if (trussinfo->flags & COUNTONLY)
                print_summary(trussinfo);

        fflush(trussinfo->outfile);

        return (0);
}