312 lines
8.5 KiB
C
312 lines
8.5 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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#ifndef lint
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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/*
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* FreeBSD/386-specific system call handling. This is probably the most
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* complex part of the entire truss program, although I've got lots of
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* it handled relatively cleanly now. The system call names are generated
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* automatically, thanks to /usr/src/sys/kern/syscalls.master. The
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* names used for the various structures are confusing, I sadly admit.
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <signal.h>
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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 <sys/ioctl.h>
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#include <sys/pioctl.h>
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#include <machine/reg.h>
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#include <machine/psl.h>
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#include <sys/syscall.h>
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#include "syscall.h"
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static int fd = -1;
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static int cpid = -1;
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extern int Procfd;
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extern FILE *outfile;
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#include "syscalls.h"
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static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]);
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/*
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* This is what this particular file uses to keep track of a system call.
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* It is probably not quite sufficient -- I can probably use the same
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* structure for the various syscall personalities, and I also probably
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* need to nest system calls (for signal handlers).
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*
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* 'struct syscall' describes the system call; it may be NULL, however,
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* if we don't know about this particular system call yet.
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*/
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static struct freebsd_syscall {
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struct syscall *sc;
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char *name;
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int number;
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unsigned long *args;
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int nargs; /* number of arguments -- *not* number of words! */
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char **s_args; /* the printable arguments */
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} fsc;
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/* Clear up and free parts of the fsc structure. */
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static inline void
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clear_fsc() {
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if (fsc.args) {
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free(fsc.args);
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}
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if (fsc.s_args) {
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int i;
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for (i = 0; i < fsc.nargs; i++)
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if (fsc.s_args[i])
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free(fsc.s_args[i]);
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free(fsc.s_args);
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}
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memset(&fsc, 0, sizeof(fsc));
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}
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/*
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* Called when a process has entered a system call. nargs is the
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* number of words, not number of arguments (a necessary distinction
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* in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c
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* is ever changed these functions need to keep up.
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*/
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void
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i386_syscall_entry(int pid, int nargs) {
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char buf[32];
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struct reg regs = { 0 };
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int syscall;
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int i;
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unsigned int parm_offset;
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struct syscall *sc;
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if (fd == -1 || pid != cpid) {
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sprintf(buf, "/proc/%d/regs", pid);
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fd = open(buf, O_RDWR);
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if (fd == -1) {
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fprintf(outfile, "-- CANNOT READ REGISTERS --\n");
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return;
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}
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cpid = pid;
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}
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clear_fsc();
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lseek(fd, 0L, 0);
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i = read(fd, ®s, sizeof(regs));
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parm_offset = regs.r_esp + sizeof(int);
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/*
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* FreeBSD has two special kinds of system call redirctions --
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* SYS_syscall, and SYS___syscall. The former is the old syscall()
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* routine, basicly; the latter is for quad-aligned arguments.
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*/
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syscall = regs.r_eax;
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switch (syscall) {
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case SYS_syscall:
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lseek(Procfd, parm_offset, SEEK_SET);
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read(Procfd, &syscall, sizeof(int));
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parm_offset += sizeof(int);
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break;
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case SYS___syscall:
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lseek(Procfd, parm_offset, SEEK_SET);
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read(Procfd, &syscall, sizeof(int));
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parm_offset += sizeof(quad_t);
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break;
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}
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fsc.number = syscall;
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fsc.name =
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(syscall < 0 || syscall > nsyscalls) ? NULL : syscallnames[syscall];
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if (!fsc.name) {
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fprintf(outfile, "-- UNKNOWN SYSCALL %d --\n", syscall);
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}
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if (nargs == 0)
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return;
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fsc.args = malloc((1+nargs) * sizeof(unsigned long));
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lseek(Procfd, parm_offset, SEEK_SET);
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if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1)
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return;
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sc = get_syscall(fsc.name);
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if (sc) {
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fsc.nargs = sc->nargs;
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} else {
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#if DEBUG
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fprintf(outfile, "unknown syscall %s -- setting args to %d\n",
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fsc.name, nargs);
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#endif
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fsc.nargs = nargs;
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}
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fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
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memset(fsc.s_args, 0, fsc.nargs * sizeof(char*));
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fsc.sc = sc;
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/*
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* At this point, we set up the system call arguments.
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* We ignore any OUT ones, however -- those are arguments that
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* are set by the system call, and so are probably meaningless
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* now. This doesn't currently support arguments that are
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* passed in *and* out, however.
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*/
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if (fsc.name) {
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#if DEBUG
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fprintf(stderr, "syscall %s(", fsc.name);
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#endif
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for (i = 0; i < fsc.nargs; i++) {
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#if DEBUG
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fprintf(stderr, "0x%x%s",
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sc
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? fsc.args[sc->args[i].offset]
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: fsc.args[i],
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i < (fsc.nargs -1) ? "," : "");
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#endif
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if (sc && !(sc->args[i].type & OUT)) {
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fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args);
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}
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}
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#if DEBUG
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fprintf(stderr, ")\n");
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#endif
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}
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#if DEBUG
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fprintf(outfile, "\n");
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#endif
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/*
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* Some system calls should be printed out before they are done --
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* execve() and exit(), for example, never return. Possibly change
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* this to work for any system call that doesn't have an OUT
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* parameter?
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*/
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if (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) {
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print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args);
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}
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return;
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}
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/*
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* And when the system call is done, we handle it here.
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* Currently, no attempt is made to ensure that the system calls
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* match -- this needs to be fixed (and is, in fact, why S_SCX includes
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* the sytem call number instead of, say, an error status).
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*/
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void
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i386_syscall_exit(int pid, int syscall) {
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char buf[32];
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struct reg regs;
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int retval;
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int i;
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int errorp;
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struct syscall *sc;
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if (fd == -1 || pid != cpid) {
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sprintf(buf, "/proc/%d/regs", pid);
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fd = open(buf, O_RDONLY);
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if (fd == -1) {
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fprintf(outfile, "-- CANNOT READ REGISTERS --\n");
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return;
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}
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cpid = pid;
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}
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lseek(fd, 0L, 0);
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if (read(fd, ®s, sizeof(regs)) != sizeof(regs))
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return;
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retval = regs.r_eax;
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errorp = !!(regs.r_eflags & PSL_C);
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/*
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* This code, while simpler than the initial versions I used, could
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* stand some significant cleaning.
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*/
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sc = fsc.sc;
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if (!sc) {
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for (i = 0; i < fsc.nargs; i++) {
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fsc.s_args[i] = malloc(12);
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sprintf(fsc.s_args[i], "0x%lx", fsc.args[i]);
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}
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} else {
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/*
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* Here, we only look for arguments that have OUT masked in --
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* otherwise, they were handled in the syscall_entry function.
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*/
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for (i = 0; i < sc->nargs; i++) {
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char *temp;
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if (sc->args[i].type & OUT) {
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/*
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* If an error occurred, than don't bothe getting the data;
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* it may not be valid.
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*/
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if (errorp) {
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temp = malloc(12);
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sprintf(temp, "0x%lx", fsc.args[sc->args[i].offset]);
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} else {
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temp = print_arg(Procfd, &sc->args[i], fsc.args);
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}
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fsc.s_args[i] = temp;
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}
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}
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}
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/*
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* It would probably be a good idea to merge the error handling,
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* but that complicates things considerably.
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*/
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print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args);
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if (errorp) {
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fprintf(outfile, "errno %d '%s'\n", retval, strerror(retval));
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} else {
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fprintf(outfile, "returns %d (0x%x)\n", retval, retval);
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}
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clear_fsc();
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return;
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}
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