/*-
* 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>
__FBSDID("$FreeBSD$");
/*
* Various setup functions for truss. Not the cleanest-written code,
* I'm afraid.
*/
#include <sys/param.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <sys/wait.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 <machine/reg.h>
#include "truss.h"
#include "extern.h"
static sig_atomic_t detaching;
/*
* setup_and_wait() is called to start a process. All it really does
* is fork(), set itself up to stop on exec or exit, and then exec
* the given command. At that point, the child process stops, and
* the parent can wake up and deal with it.
*/
int
setup_and_wait(char *command[])
{
pid_t pid;
pid = vfork();
if (pid == -1)
err(1, "fork failed");
if (pid == 0) { /* Child */
ptrace(PT_TRACE_ME, 0, 0, 0);
execvp(command[0], command);
err(1, "execvp %s", command[0]);
}
/* Only in the parent here */
if (waitpid(pid, NULL, 0) < 0)
err(1, "unexpect stop in waitpid");
return (pid);
}
/*
* start_tracing picks up where setup_and_wait() dropped off -- namely,
* it sets the event mask for the given process id. Called for both
* monitoring an existing process and when we create our own.
*/
int
start_tracing(pid_t pid)
{
int ret, retry;
retry = 10;
do {
ret = ptrace(PT_ATTACH, pid, NULL, 0);
usleep(200);
} while (ret && retry-- > 0);
if (ret)
err(1, "can not attach to target process");
if (waitpid(pid, NULL, 0) < 0)
err(1, "Unexpect stop in waitpid");
return (0);
}
/*
* Restore a process back to it's pre-truss state.
* Called for SIGINT, SIGTERM, SIGQUIT. This only
* applies if truss was told to monitor an already-existing
* process.
*/
void
restore_proc(int signo __unused)
{
detaching = 1;
}
static int
detach_proc(pid_t pid)
{
int waitval;
/* stop the child so that we can detach */
kill(pid, SIGSTOP);
if (waitpid(pid, &waitval, 0) < 0)
err(1, "Unexpected stop in waitpid");
if (ptrace(PT_DETACH, pid, (caddr_t)1, 0) < 0)
err(1, "Can not detach the process");
kill(pid, SIGCONT);
return (waitval);
}
/*
* Change curthread member based on lwpid.
* If it is a new thread, create a threadinfo structure
*/
static void
find_thread(struct trussinfo *info, lwpid_t lwpid)
{
struct threadinfo *np;
info->curthread = NULL;
SLIST_FOREACH(np, &info->threadlist, entries) {
if (np->tid == lwpid) {
info->curthread = np;
return;
}
}
np = (struct threadinfo *)calloc(1, sizeof(struct threadinfo));
if (np == NULL)
err(1, "calloc() failed");
np->tid = lwpid;
SLIST_INSERT_HEAD(&info->threadlist, np, entries);
info->curthread = np;
}
/*
* Start the traced process and wait until it stoped.
* Fill trussinfo structure.
* When this even returns, the traced process is in stop state.
*/
void
waitevent(struct trussinfo *info)
{
struct ptrace_lwpinfo lwpinfo;
static int pending_signal = 0;
int waitval;
ptrace(PT_SYSCALL, info->pid, (caddr_t)1, pending_signal);
pending_signal = 0;
detach:
if (detaching) {
waitval = detach_proc(info->pid);
info->pr_why = S_DETACHED;
info->pr_data = WEXITSTATUS(waitval);
return;
}
if (waitpid(info->pid, &waitval, 0) == -1) {
if (errno == EINTR)
goto detach;
err(1, "Unexpected stop in waitpid");
}
if (WIFCONTINUED(waitval)) {
info->pr_why = S_NONE;
return;
}
if (WIFEXITED(waitval)) {
info->pr_why = S_EXIT;
info->pr_data = WEXITSTATUS(waitval);
return;
}
if (WIFSTOPPED(waitval)) {
ptrace(PT_LWPINFO, info->pid, (caddr_t)&lwpinfo,
sizeof(lwpinfo));
find_thread(info, lwpinfo.pl_lwpid);
switch (WSTOPSIG(waitval)) {
case SIGTRAP:
if (lwpinfo.pl_flags & PL_FLAG_SCE) {
info->pr_why = S_SCE;
info->curthread->in_syscall = 1;
break;
} else if (lwpinfo.pl_flags & PL_FLAG_SCX) {
info->pr_why = S_SCX;
info->curthread->in_syscall = 0;
break;
} else {
errx(1,
"pl_flags %x contains neither PL_FLAG_SCE nor PL_FLAG_SCX",
lwpinfo.pl_flags);
}
default:
info->pr_why = S_SIG;
info->pr_data = WSTOPSIG(waitval);
pending_signal = info->pr_data;
break;
}
}
if (WIFSIGNALED(waitval)) {
info->pr_why = S_EXIT;
info->pr_data = 0;
return;
}
}
