d7b7dcba41
change from ioctl(fd, PIOC<foo>, &i); to ioctl(fd, PIOC<foo>, i); This is going from the _IOW to _IO ioctl macro. The kernel, procctl, and truss must be in synch for it all to work (not doing so will get errors about inappropriate ioctl's, fortunately). Hopefully I didn't forget anything :).
142 lines
3.2 KiB
C
142 lines
3.2 KiB
C
/*
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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 1.4 1997/12/07 04:08:48 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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