174 lines
4.9 KiB
C
174 lines
4.9 KiB
C
/*
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* Copryight 1997 Sean Eric Fagan
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Sean Eric Fagan
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* 4. Neither the name of the author may be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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/*
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* Various setup functions for truss. Not the cleanest-written code,
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* I'm afraid.
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*/
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/*
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* $Id: setup.c,v 1.5 1997/12/13 03:13:47 sef Exp $
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include <err.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <sys/ioctl.h>
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#include <sys/pioctl.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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static int evflags = 0;
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/*
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* setup_and_wait() is called to start a process. All it really does
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* is vfork(), set itself up to stop on exec or exit, and then exec
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* the given command. At that point, the child process stops, and
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* the parent can wake up and deal with it.
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*/
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int
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setup_and_wait(char *command[]) {
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struct procfs_status pfs;
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char buf[32];
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int fd;
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int pid;
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extern char *prog;
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int flags;
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pid = vfork();
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if (pid == -1) {
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err(1, "vfork failed");
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}
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if (pid == 0) { /* Child */
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int mask = S_EXEC | S_EXIT;
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fd = open("/proc/curproc/mem", O_WRONLY);
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if (fd == -1)
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err(2, "cannot open /proc/curproc/mem");
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fcntl(fd, F_SETFD, 1);
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if (ioctl(fd, PIOCBIS, mask) == -1)
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err(3, "PIOCBIS");
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flags = PF_LINGER;
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/*
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* The PF_LINGER flag tells procfs not to wake up the
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* process on last close; normally, this is the behaviour
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* we want.
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*/
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if (ioctl(fd, PIOCSFL, flags) == -1)
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perror("cannot set PF_LINGER");
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execvp(command[0], command);
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mask = ~0;
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ioctl(fd, PIOCBIC, ~0);
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err(4, "execvp %s", command[0]);
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}
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/* Only in the parent here */
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if (waitpid(pid, NULL, WNOHANG) != 0) {
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/*
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* Process exited before it got to us -- meaning the exec failed
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* miserably -- so we just quietly exit.
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*/
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exit(1);
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}
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sprintf(buf, "/proc/%d/mem", pid);
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if ((fd = open(buf, O_RDWR)) == -1)
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err(5, "cannot open %s", buf);
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if (ioctl(fd, PIOCWAIT, &pfs) == -1)
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err(6, "PIOCWAIT");
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if (pfs.why == S_EXIT) {
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fprintf(stderr, "process exited before exec'ing\n");
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ioctl(fd, PIOCCONT, 0);
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wait(0);
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exit(7);
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}
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close(fd);
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return pid;
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}
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/*
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* start_tracing picks up where setup_and_wait() dropped off -- namely,
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* it sets the event mask for the given process id. Called for both
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* monitoring an existing process and when we create our own.
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*/
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int
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start_tracing(int pid, int flags) {
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int fd;
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char buf[32];
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struct procfs_status tmp;
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sprintf(buf, "/proc/%d/mem", pid);
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fd = open(buf, O_RDWR);
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if (fd == -1)
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err(8, "cannot open %s", buf);
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if (ioctl(fd, PIOCSTATUS, &tmp) == -1) {
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err(10, "cannot get procfs status struct");
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}
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evflags = tmp.events;
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if (ioctl(fd, PIOCBIS, flags) == -1)
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err(9, "cannot set procfs event bit mask");
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/*
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* This clears the PF_LINGER set above in setup_and_wait();
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* if truss happens to die before this, then the process
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* needs to be woken up via procctl.
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*/
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if (ioctl(fd, PIOCSFL, 0) == -1)
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perror("cannot clear PF_LINGER");
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return fd;
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}
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/*
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* Restore a process back to it's pre-truss state.
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* Called for SIGINT, SIGTERM, SIGQUIT. This only
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* applies if truss was told to monitor an already-existing
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* process.
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*/
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void
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restore_proc(int signo) {
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extern int Procfd;
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ioctl(Procfd, PIOCBIC, ~0);
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if (evflags)
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ioctl(Procfd, PIOCBIS, evflags);
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exit(0);
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}
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