freebsd-dev/usr.bin/truss/i386-fbsd.c
Alfred Perlstein 2bae4eb308 Support readlink(2) better. Readlink does not nul terminate the
result buffer, so we need to format it ourselves.  The problem is
that the length is stored as the return value from readlink, so we
need to pass the return value from our syscall into print_arg.

Motivated by: truss garbage on my screen from reading /etc/malloc.conf.
2004-07-17 19:48:49 +00:00

340 lines
9.5 KiB
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.
*/
#ifndef lint
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
/*
* FreeBSD/i386-specific system call handling. This is probably the most
* complex part of the entire truss program, although I've got lots of
* it handled relatively cleanly now. The system call names are generated
* automatically, thanks to /usr/src/sys/kern/syscalls.master. The
* names used for the various structures are confusing, I sadly admit.
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/pioctl.h>
#include <sys/syscall.h>
#include <machine/reg.h>
#include <machine/psl.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 "syscall.h"
#include "extern.h"
static int fd = -1;
static int cpid = -1;
#include "syscalls.h"
static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]);
/*
* This is what this particular file uses to keep track of a system call.
* It is probably not quite sufficient -- I can probably use the same
* structure for the various syscall personalities, and I also probably
* need to nest system calls (for signal handlers).
*
* 'struct syscall' describes the system call; it may be NULL, however,
* if we don't know about this particular system call yet.
*/
static struct freebsd_syscall {
struct syscall *sc;
const char *name;
int number;
unsigned long *args;
int nargs; /* number of arguments -- *not* number of words! */
char **s_args; /* the printable arguments */
} fsc;
/* Clear up and free parts of the fsc structure. */
static __inline void
clear_fsc(void) {
if (fsc.args) {
free(fsc.args);
}
if (fsc.s_args) {
int i;
for (i = 0; i < fsc.nargs; i++)
if (fsc.s_args[i])
free(fsc.s_args[i]);
free(fsc.s_args);
}
memset(&fsc, 0, sizeof(fsc));
}
/*
* Called when a process has entered a system call. nargs is the
* number of words, not number of arguments (a necessary distinction
* in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c
* is ever changed these functions need to keep up.
*/
void
i386_syscall_entry(struct trussinfo *trussinfo, int nargs) {
char buf[32];
struct reg regs;
int syscall_num;
int i;
unsigned int parm_offset;
struct syscall *sc;
if (fd == -1 || trussinfo->pid != cpid) {
sprintf(buf, "/proc/%d/regs", trussinfo->pid);
fd = open(buf, O_RDWR);
if (fd == -1) {
fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n");
return;
}
cpid = trussinfo->pid;
}
clear_fsc();
lseek(fd, 0L, 0);
if (read(fd, &regs, sizeof(regs)) != sizeof(regs)) {
fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
return;
}
parm_offset = regs.r_esp + sizeof(int);
/*
* FreeBSD has two special kinds of system call redirctions --
* SYS_syscall, and SYS___syscall. The former is the old syscall()
* routine, basicly; the latter is for quad-aligned arguments.
*/
syscall_num = regs.r_eax;
switch (syscall_num) {
case SYS_syscall:
lseek(Procfd, parm_offset, SEEK_SET);
read(Procfd, &syscall_num, sizeof(int));
parm_offset += sizeof(int);
break;
case SYS___syscall:
lseek(Procfd, parm_offset, SEEK_SET);
read(Procfd, &syscall_num, sizeof(int));
parm_offset += sizeof(quad_t);
break;
}
fsc.number = syscall_num;
fsc.name =
(syscall_num < 0 || syscall_num > nsyscalls) ? NULL : syscallnames[syscall_num];
if (!fsc.name) {
fprintf(trussinfo->outfile, "-- UNKNOWN SYSCALL %d --\n", syscall_num);
}
if (fsc.name && (trussinfo->flags & FOLLOWFORKS)
&& ((!strcmp(fsc.name, "fork")
|| !strcmp(fsc.name, "rfork")
|| !strcmp(fsc.name, "vfork"))))
{
trussinfo->in_fork = 1;
}
if (nargs == 0)
return;
fsc.args = malloc((1+nargs) * sizeof(unsigned long));
lseek(Procfd, parm_offset, SEEK_SET);
if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1)
return;
sc = get_syscall(fsc.name);
if (sc) {
fsc.nargs = sc->nargs;
} else {
#if DEBUG
fprintf(trussinfo->outfile, "unknown syscall %s -- setting args to %d\n",
fsc.name, nargs);
#endif
fsc.nargs = nargs;
}
fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*));
memset(fsc.s_args, 0, fsc.nargs * sizeof(char*));
fsc.sc = sc;
/*
* At this point, we set up the system call arguments.
* We ignore any OUT ones, however -- those are arguments that
* are set by the system call, and so are probably meaningless
* now. This doesn't currently support arguments that are
* passed in *and* out, however.
*/
if (fsc.name) {
#if DEBUG
fprintf(stderr, "syscall %s(", fsc.name);
#endif
for (i = 0; i < fsc.nargs; i++) {
#if DEBUG
fprintf(stderr, "0x%x%s",
sc
? fsc.args[sc->args[i].offset]
: fsc.args[i],
i < (fsc.nargs - 1) ? "," : "");
#endif
if (sc && !(sc->args[i].type & OUT)) {
fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args, 0);
}
}
#if DEBUG
fprintf(stderr, ")\n");
#endif
}
#if DEBUG
fprintf(trussinfo->outfile, "\n");
#endif
/*
* Some system calls should be printed out before they are done --
* execve() and exit(), for example, never return. Possibly change
* this to work for any system call that doesn't have an OUT
* parameter?
*/
if (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) {
/* XXX
* This could be done in a more general
* manner but it still wouldn't be very pretty.
*/
if (!strcmp(fsc.name, "execve")) {
if ((trussinfo->flags & EXECVEARGS) == 0)
if (fsc.s_args[1]) {
free(fsc.s_args[1]);
fsc.s_args[1] = NULL;
}
if ((trussinfo->flags & EXECVEENVS) == 0)
if (fsc.s_args[2]) {
free(fsc.s_args[2]);
fsc.s_args[2] = NULL;
}
}
print_syscall(trussinfo, fsc.name, fsc.nargs, fsc.s_args);
fprintf(trussinfo->outfile, "\n");
}
return;
}
/*
* And when the system call is done, we handle it here.
* Currently, no attempt is made to ensure that the system calls
* match -- this needs to be fixed (and is, in fact, why S_SCX includes
* the sytem call number instead of, say, an error status).
*/
long
i386_syscall_exit(struct trussinfo *trussinfo, int syscall_num __unused)
{
char buf[32];
struct reg regs;
long retval;
int i;
int errorp;
struct syscall *sc;
if (fd == -1 || trussinfo->pid != cpid) {
sprintf(buf, "/proc/%d/regs", trussinfo->pid);
fd = open(buf, O_RDONLY);
if (fd == -1) {
fprintf(trussinfo->outfile, "-- CANNOT OPEN REGISTERS --\n");
return (-1);
}
cpid = trussinfo->pid;
}
lseek(fd, 0L, 0);
if (read(fd, &regs, sizeof(regs)) != sizeof(regs)) {
fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
return (-1);
}
retval = regs.r_eax;
errorp = !!(regs.r_eflags & PSL_C);
/*
* This code, while simpler than the initial versions I used, could
* stand some significant cleaning.
*/
sc = fsc.sc;
if (!sc) {
for (i = 0; i < fsc.nargs; i++)
asprintf(&fsc.s_args[i], "0x%lx", fsc.args[i]);
} else {
/*
* Here, we only look for arguments that have OUT masked in --
* otherwise, they were handled in the syscall_entry function.
*/
for (i = 0; i < sc->nargs; i++) {
char *temp;
if (sc->args[i].type & OUT) {
/*
* If an error occurred, than don't bothe getting the data;
* it may not be valid.
*/
if (errorp)
asprintf(&temp, "0x%lx", fsc.args[sc->args[i].offset]);
else
temp = print_arg(Procfd, &sc->args[i], fsc.args, retval);
fsc.s_args[i] = temp;
}
}
}
/*
* It would probably be a good idea to merge the error handling,
* but that complicates things considerably.
*/
print_syscall_ret(trussinfo, fsc.name, fsc.nargs, fsc.s_args, errorp, retval);
clear_fsc();
return (retval);
}