freebsd-dev/usr.bin/truss/main.c

/*
 * Copryight 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>
__FBSDID("$FreeBSD$");

/*
 * The main module for truss.  Suprisingly 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/param.h>
#include <sys/ioctl.h>
#include <sys/pioctl.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

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

/*
 * It's difficult to parameterize this because it must be
 * accessible in a signal handler.
 */

int Procfd;

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

/*
 * WARNING! "FreeBSD a.out" must be first, or set_etype will not
 * work correctly.
 */
struct ex_types {
	const char *type;
	void (*enter_syscall)(struct trussinfo *, int);
	long (*exit_syscall)(struct trussinfo *, int);
} ex_types[] = {
#ifdef __alpha__
	{ "FreeBSD ELF", alpha_syscall_entry, alpha_syscall_exit },
#endif
#ifdef __amd64__
	{ "FreeBSD ELF64", amd64_syscall_entry, amd64_syscall_exit },
#endif
#ifdef __i386__
	{ "FreeBSD a.out", i386_syscall_entry, i386_syscall_exit },
	{ "FreeBSD ELF", i386_syscall_entry, i386_syscall_exit },
	{ "FreeBSD ELF32", i386_syscall_entry, i386_syscall_exit },
	{ "Linux ELF", i386_linux_syscall_entry, i386_linux_syscall_exit },
#endif
#ifdef __ia64__
	{ "FreeBSD ELF64", ia64_syscall_entry, ia64_syscall_exit },
#endif
#ifdef __sparc64__
	{ "FreeBSD ELF64", sparc64_syscall_entry, sparc64_syscall_exit },
#endif
	{ 0, 0, 0 },
};

/*
 * Set the execution type.  This is called after every exec, and when
 * a process is first monitored.  The procfs pseudo-file "etype" has
 * the execution module type -- see /proc/curproc/etype for an example.
 */

static struct ex_types *
set_etype(struct trussinfo *trussinfo)
{
	struct ex_types *funcs;
	char etype[24];
	char progt[32];
	int fd;

	sprintf(etype, "/proc/%d/etype", trussinfo->pid);
	if ((fd = open(etype, O_RDONLY)) == -1) {
		strcpy(progt, "FreeBSD a.out");
	} else {
		int len = read(fd, progt, sizeof(progt));
		progt[len-1] = '\0';
		close(fd);
	}

	for (funcs = ex_types; funcs->type; funcs++)
		if (!strcmp(funcs->type, progt))
			break;

	if (funcs->type == NULL) {
		funcs = &ex_types[0];
		warn("execution type %s is not supported -- using %s",
		    progt, funcs->type);
	}
	return (funcs);
}

char *
strsig(int sig)
{
	char *ret;

	ret = NULL;
	if (sig > 0 && sig < NSIG) {
		int i;
		asprintf(&ret, "sig%s", sys_signame[sig]);
		if (ret == NULL)
			return (NULL);
		for (i = 0; ret[i] != '\0'; ++i)
			ret[i] = toupper(ret[i]);
	}
	return (ret);
}

int
main(int ac, char **av)
{
	int c;
	int i;
	char **command;
	struct procfs_status pfs;
	struct ex_types *funcs;
	int in_exec, sigexit, initial_open;
	char *fname;
	struct trussinfo *trussinfo;
	char *signame;

	in_exec = 0;
	sigexit = 0;
	fname = NULL;
	initial_open = 1;

	/* Initialize the trussinfo struct */
	trussinfo = (struct trussinfo *)malloc(sizeof(struct trussinfo));
	if (trussinfo == NULL)
		errx(1, "malloc() failed");
	bzero(trussinfo, sizeof(struct trussinfo));
	trussinfo->outfile = stderr;

	while ((c = getopt(ac, av, "p:o:faedDS")) != -1) {
		switch (c) {
		case 'p':	/* specified pid */
			trussinfo->pid = atoi(optarg);
			break;
		case 'f': /* Follow fork()'s */
			trussinfo->flags |= FOLLOWFORKS;
			break;
		case 'a': /* Print execve() argument strings. */
			trussinfo->flags |= EXECVEARGS;
			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':	/* Don't trace signals */ 
			trussinfo->flags |= NOSIGS;
			break;
		default:
			usage();
		}
	}

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

	if (fname != NULL) { /* Use output file */
		if ((trussinfo->outfile = fopen(fname, "w")) == NULL)
			errx(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 (trussinfo->pid == 0) {	/* Start a command ourselves */
		command = av;
		trussinfo->pid = setup_and_wait(command);
		signal(SIGINT, SIG_IGN);
		signal(SIGTERM, SIG_IGN);
		signal(SIGQUIT, SIG_IGN);
	} else {
		signal(SIGINT, restore_proc);
		signal(SIGTERM, restore_proc);
		signal(SIGQUIT, restore_proc);
	}


	/*
	 * At this point, if we started the process, it is stopped waiting to
	 * be woken up, either in exit() or in execve().
	 */

START_TRACE:
	Procfd = start_tracing(
	    trussinfo->pid, initial_open,
	    S_EXEC | S_SCE | S_SCX | S_CORE | S_EXIT |
	    ((trussinfo->flags & NOSIGS) ? 0 : S_SIG),
	    ((trussinfo->flags & FOLLOWFORKS) ? PF_FORK : 0));
	initial_open = 0;
	if (Procfd == -1)
		return (0);

	pfs.why = 0;

	funcs = set_etype(trussinfo);
	/*
	 * 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);

	do {
		int val = 0;

		if (ioctl(Procfd, PIOCWAIT, &pfs) == -1)
			warn("PIOCWAIT top of loop");
		else {
			switch(i = pfs.why) {
			case S_SCE:
				funcs->enter_syscall(trussinfo, pfs.val);
				clock_gettime(CLOCK_REALTIME,
				    &trussinfo->before);
				break;
			case S_SCX:
				clock_gettime(CLOCK_REALTIME,
				    &trussinfo->after);
				/*
				 * This is so we don't get two messages for
				 * an exec -- one for the S_EXEC, and one for
				 * the syscall exit.  It also, conveniently,
				 * ensures that the first message printed out
				 * isn't the return-from-syscall used to
				 * create the process.
				 */
				if (in_exec) {
					in_exec = 0;
					break;
				}

				if (trussinfo->in_fork &&
				    (trussinfo->flags & FOLLOWFORKS)) {
					int childpid;

					trussinfo->in_fork = 0;
					childpid =
					    funcs->exit_syscall(trussinfo,
						pfs.val);

					/*
					 * Fork a new copy of ourself to trace
					 * the child of the original traced
					 * process.
					 */
					if (fork() == 0) {
						trussinfo->pid = childpid;
						goto START_TRACE;
					}
					break;
				}
				funcs->exit_syscall(trussinfo, pfs.val);
				break;
			case S_SIG:
				signame = strsig(pfs.val);
				fprintf(trussinfo->outfile,
				    "SIGNAL %lu (%s)\n", pfs.val,
				    signame == NULL ? "?" : signame);
				free(signame);
				sigexit = pfs.val;
				break;
			case S_EXIT:
				fprintf(trussinfo->outfile,
				    "process exit, rval = %lu\n", pfs.val);
				break;
			case S_EXEC:
				funcs = set_etype(trussinfo);
				in_exec = 1;
				break;
			default:
				fprintf(trussinfo->outfile,
				    "Process stopped because of:  %d\n", i);
				break;
			}
		}
		if (ioctl(Procfd, PIOCCONT, val) == -1) {
			if (kill(trussinfo->pid, 0) == -1 && errno == ESRCH)
				break;
			else
				warn("PIOCCONT");
		}
	} while (pfs.why != S_EXIT);
	fflush(trussinfo->outfile);
	if (sigexit) {
		struct rlimit rlp;

		rlp.rlim_cur = 0;
		rlp.rlim_max = 0;
		setrlimit(RLIMIT_CORE, &rlp);
		(void) signal(sigexit, SIG_DFL);
		(void) kill(getpid(), sigexit);
	}
	return (0);
}