freebsd-dev/usr.bin/truss/setup.c
John Baldwin 13e5e6b616 Decode signal information returned by system calls.
Specifically, decode the siginfo structure returned by sigtimedwait(),
sigwaitinfo(), and wait6().  While here, also decode the signal number
returned in the second argument to sigwait().
2017-08-30 15:45:23 +00:00

747 lines
18 KiB
C

/*-
* 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/ptrace.h>
#include <sys/sysctl.h>
#include <sys/wait.h>
#include <assert.h>
#include <err.h>
#include <errno.h>
#include <signal.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysdecode.h>
#include <time.h>
#include <unistd.h>
#include "truss.h"
#include "syscall.h"
#include "extern.h"
SET_DECLARE(procabi, struct procabi);
static sig_atomic_t detaching;
static void enter_syscall(struct trussinfo *, struct threadinfo *,
struct ptrace_lwpinfo *);
static void new_proc(struct trussinfo *, pid_t, lwpid_t);
/*
* setup_and_wait() is called to start a process. All it really does
* is fork(), enable tracing in the child, and then exec the given
* command. At that point, the child process stops, and the parent
* can wake up and deal with it.
*/
void
setup_and_wait(struct trussinfo *info, 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");
new_proc(info, pid, 0);
}
/*
* start_tracing is called to attach to an existing process.
*/
void
start_tracing(struct trussinfo *info, 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");
new_proc(info, pid, 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 void
detach_proc(pid_t pid)
{
/* stop the child so that we can detach */
kill(pid, SIGSTOP);
if (waitpid(pid, NULL, 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);
}
/*
* Determine the ABI. This is called after every exec, and when
* a process is first monitored.
*/
static struct procabi *
find_abi(pid_t pid)
{
struct procabi **pabi;
size_t len;
int error;
int mib[4];
char progt[32];
len = sizeof(progt);
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_SV_NAME;
mib[3] = pid;
error = sysctl(mib, 4, progt, &len, NULL, 0);
if (error != 0)
err(2, "can not get sysvec name");
SET_FOREACH(pabi, procabi) {
if (strcmp((*pabi)->type, progt) == 0)
return (*pabi);
}
warnx("ABI %s for pid %ld is not supported", progt, (long)pid);
return (NULL);
}
static struct threadinfo *
new_thread(struct procinfo *p, lwpid_t lwpid)
{
struct threadinfo *nt;
/*
* If this happens it means there is a bug in truss. Unfortunately
* this will kill any processes truss is attached to.
*/
LIST_FOREACH(nt, &p->threadlist, entries) {
if (nt->tid == lwpid)
errx(1, "Duplicate thread for LWP %ld", (long)lwpid);
}
nt = calloc(1, sizeof(struct threadinfo));
if (nt == NULL)
err(1, "calloc() failed");
nt->proc = p;
nt->tid = lwpid;
LIST_INSERT_HEAD(&p->threadlist, nt, entries);
return (nt);
}
static void
free_thread(struct threadinfo *t)
{
LIST_REMOVE(t, entries);
free(t);
}
static void
add_threads(struct trussinfo *info, struct procinfo *p)
{
struct ptrace_lwpinfo pl;
struct threadinfo *t;
lwpid_t *lwps;
int i, nlwps;
nlwps = ptrace(PT_GETNUMLWPS, p->pid, NULL, 0);
if (nlwps == -1)
err(1, "Unable to fetch number of LWPs");
assert(nlwps > 0);
lwps = calloc(nlwps, sizeof(*lwps));
nlwps = ptrace(PT_GETLWPLIST, p->pid, (caddr_t)lwps, nlwps);
if (nlwps == -1)
err(1, "Unable to fetch LWP list");
for (i = 0; i < nlwps; i++) {
t = new_thread(p, lwps[i]);
if (ptrace(PT_LWPINFO, lwps[i], (caddr_t)&pl, sizeof(pl)) == -1)
err(1, "ptrace(PT_LWPINFO)");
if (pl.pl_flags & PL_FLAG_SCE) {
info->curthread = t;
enter_syscall(info, t, &pl);
}
}
free(lwps);
}
static void
new_proc(struct trussinfo *info, pid_t pid, lwpid_t lwpid)
{
struct procinfo *np;
/*
* If this happens it means there is a bug in truss. Unfortunately
* this will kill any processes truss is attached to.
*/
LIST_FOREACH(np, &info->proclist, entries) {
if (np->pid == pid)
errx(1, "Duplicate process for pid %ld", (long)pid);
}
if (info->flags & FOLLOWFORKS)
if (ptrace(PT_FOLLOW_FORK, pid, NULL, 1) == -1)
err(1, "Unable to follow forks for pid %ld", (long)pid);
if (ptrace(PT_LWP_EVENTS, pid, NULL, 1) == -1)
err(1, "Unable to enable LWP events for pid %ld", (long)pid);
np = calloc(1, sizeof(struct procinfo));
np->pid = pid;
np->abi = find_abi(pid);
LIST_INIT(&np->threadlist);
LIST_INSERT_HEAD(&info->proclist, np, entries);
if (lwpid != 0)
new_thread(np, lwpid);
else
add_threads(info, np);
}
static void
free_proc(struct procinfo *p)
{
struct threadinfo *t, *t2;
LIST_FOREACH_SAFE(t, &p->threadlist, entries, t2) {
free(t);
}
LIST_REMOVE(p, entries);
free(p);
}
static void
detach_all_procs(struct trussinfo *info)
{
struct procinfo *p, *p2;
LIST_FOREACH_SAFE(p, &info->proclist, entries, p2) {
detach_proc(p->pid);
free_proc(p);
}
}
static struct procinfo *
find_proc(struct trussinfo *info, pid_t pid)
{
struct procinfo *np;
LIST_FOREACH(np, &info->proclist, entries) {
if (np->pid == pid)
return (np);
}
return (NULL);
}
/*
* Change curthread member based on (pid, lwpid).
*/
static void
find_thread(struct trussinfo *info, pid_t pid, lwpid_t lwpid)
{
struct procinfo *np;
struct threadinfo *nt;
np = find_proc(info, pid);
assert(np != NULL);
LIST_FOREACH(nt, &np->threadlist, entries) {
if (nt->tid == lwpid) {
info->curthread = nt;
return;
}
}
errx(1, "could not find thread");
}
/*
* When a process exits, it should have exactly one thread left.
* All of the other threads should have reported thread exit events.
*/
static void
find_exit_thread(struct trussinfo *info, pid_t pid)
{
struct procinfo *p;
p = find_proc(info, pid);
assert(p != NULL);
info->curthread = LIST_FIRST(&p->threadlist);
assert(info->curthread != NULL);
assert(LIST_NEXT(info->curthread, entries) == NULL);
}
static void
alloc_syscall(struct threadinfo *t, struct ptrace_lwpinfo *pl)
{
u_int i;
assert(t->in_syscall == 0);
assert(t->cs.number == 0);
assert(t->cs.sc == NULL);
assert(t->cs.nargs == 0);
for (i = 0; i < nitems(t->cs.s_args); i++)
assert(t->cs.s_args[i] == NULL);
memset(t->cs.args, 0, sizeof(t->cs.args));
t->cs.number = pl->pl_syscall_code;
t->in_syscall = 1;
}
static void
free_syscall(struct threadinfo *t)
{
u_int i;
for (i = 0; i < t->cs.nargs; i++)
free(t->cs.s_args[i]);
memset(&t->cs, 0, sizeof(t->cs));
t->in_syscall = 0;
}
static void
enter_syscall(struct trussinfo *info, struct threadinfo *t,
struct ptrace_lwpinfo *pl)
{
struct syscall *sc;
u_int i, narg;
alloc_syscall(t, pl);
narg = MIN(pl->pl_syscall_narg, nitems(t->cs.args));
if (narg != 0 && t->proc->abi->fetch_args(info, narg) != 0) {
free_syscall(t);
return;
}
sc = get_syscall(t, t->cs.number, narg);
if (sc->unknown)
fprintf(info->outfile, "-- UNKNOWN %s SYSCALL %d --\n",
t->proc->abi->type, t->cs.number);
t->cs.nargs = sc->nargs;
assert(sc->nargs <= nitems(t->cs.s_args));
t->cs.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 DEBUG
fprintf(stderr, "syscall %s(", sc->name);
#endif
for (i = 0; i < t->cs.nargs; i++) {
#if DEBUG
fprintf(stderr, "0x%lx%s", t->cs.args[sc->args[i].offset],
i < (t->cs.nargs - 1) ? "," : "");
#endif
if (!(sc->args[i].type & OUT)) {
t->cs.s_args[i] = print_arg(&sc->args[i],
t->cs.args, 0, info);
}
}
#if DEBUG
fprintf(stderr, ")\n");
#endif
clock_gettime(CLOCK_REALTIME, &t->before);
}
/*
* When a thread exits voluntarily (including when a thread calls
* exit() to trigger a process exit), the thread's internal state
* holds the arguments passed to the exit system call. When the
* thread's exit is reported, log that system call without a return
* value.
*/
static void
thread_exit_syscall(struct trussinfo *info)
{
struct threadinfo *t;
t = info->curthread;
if (!t->in_syscall)
return;
clock_gettime(CLOCK_REALTIME, &t->after);
print_syscall_ret(info, 0, NULL);
free_syscall(t);
}
static void
exit_syscall(struct trussinfo *info, struct ptrace_lwpinfo *pl)
{
struct threadinfo *t;
struct procinfo *p;
struct syscall *sc;
long retval[2];
u_int i;
int errorp;
t = info->curthread;
if (!t->in_syscall)
return;
clock_gettime(CLOCK_REALTIME, &t->after);
p = t->proc;
if (p->abi->fetch_retval(info, retval, &errorp) < 0) {
free_syscall(t);
return;
}
sc = t->cs.sc;
/*
* Here, we only look for arguments that have OUT masked in --
* otherwise, they were handled in enter_syscall().
*/
for (i = 0; i < sc->nargs; i++) {
char *temp;
if (sc->args[i].type & OUT) {
/*
* If an error occurred, then don't bother
* getting the data; it may not be valid.
*/
if (errorp) {
asprintf(&temp, "0x%lx",
t->cs.args[sc->args[i].offset]);
} else {
temp = print_arg(&sc->args[i],
t->cs.args, retval, info);
}
t->cs.s_args[i] = temp;
}
}
print_syscall_ret(info, errorp, retval);
free_syscall(t);
/*
* If the process executed a new image, check the ABI. If the
* new ABI isn't supported, stop tracing this process.
*/
if (pl->pl_flags & PL_FLAG_EXEC) {
assert(LIST_NEXT(LIST_FIRST(&p->threadlist), entries) == NULL);
p->abi = find_abi(p->pid);
if (p->abi == NULL) {
if (ptrace(PT_DETACH, p->pid, (caddr_t)1, 0) < 0)
err(1, "Can not detach the process");
free_proc(p);
}
}
}
int
print_line_prefix(struct trussinfo *info)
{
struct timespec timediff;
struct threadinfo *t;
int len;
len = 0;
t = info->curthread;
if (info->flags & (FOLLOWFORKS | DISPLAYTIDS)) {
if (info->flags & FOLLOWFORKS)
len += fprintf(info->outfile, "%5d", t->proc->pid);
if ((info->flags & (FOLLOWFORKS | DISPLAYTIDS)) ==
(FOLLOWFORKS | DISPLAYTIDS))
len += fprintf(info->outfile, " ");
if (info->flags & DISPLAYTIDS)
len += fprintf(info->outfile, "%6d", t->tid);
len += fprintf(info->outfile, ": ");
}
if (info->flags & ABSOLUTETIMESTAMPS) {
timespecsubt(&t->after, &info->start_time, &timediff);
len += fprintf(info->outfile, "%jd.%09ld ",
(intmax_t)timediff.tv_sec, timediff.tv_nsec);
}
if (info->flags & RELATIVETIMESTAMPS) {
timespecsubt(&t->after, &t->before, &timediff);
len += fprintf(info->outfile, "%jd.%09ld ",
(intmax_t)timediff.tv_sec, timediff.tv_nsec);
}
return (len);
}
static void
report_thread_death(struct trussinfo *info)
{
struct threadinfo *t;
t = info->curthread;
clock_gettime(CLOCK_REALTIME, &t->after);
print_line_prefix(info);
fprintf(info->outfile, "<thread %ld exited>\n", (long)t->tid);
}
static void
report_thread_birth(struct trussinfo *info)
{
struct threadinfo *t;
t = info->curthread;
clock_gettime(CLOCK_REALTIME, &t->after);
t->before = t->after;
print_line_prefix(info);
fprintf(info->outfile, "<new thread %ld>\n", (long)t->tid);
}
static void
report_exit(struct trussinfo *info, siginfo_t *si)
{
struct threadinfo *t;
t = info->curthread;
clock_gettime(CLOCK_REALTIME, &t->after);
print_line_prefix(info);
if (si->si_code == CLD_EXITED)
fprintf(info->outfile, "process exit, rval = %u\n",
si->si_status);
else
fprintf(info->outfile, "process killed, signal = %u%s\n",
si->si_status, si->si_code == CLD_DUMPED ?
" (core dumped)" : "");
}
static void
report_new_child(struct trussinfo *info)
{
struct threadinfo *t;
t = info->curthread;
clock_gettime(CLOCK_REALTIME, &t->after);
t->before = t->after;
print_line_prefix(info);
fprintf(info->outfile, "<new process>\n");
}
void
decode_siginfo(FILE *fp, siginfo_t *si)
{
const char *str;
fprintf(fp, " code=");
str = sysdecode_sigcode(si->si_signo, si->si_code);
if (str == NULL)
fprintf(fp, "%d", si->si_code);
else
fprintf(fp, "%s", str);
switch (si->si_code) {
case SI_NOINFO:
break;
case SI_QUEUE:
fprintf(fp, " value=%p", si->si_value.sival_ptr);
/* FALLTHROUGH */
case SI_USER:
case SI_LWP:
fprintf(fp, " pid=%jd uid=%jd", (intmax_t)si->si_pid,
(intmax_t)si->si_uid);
break;
case SI_TIMER:
fprintf(fp, " value=%p", si->si_value.sival_ptr);
fprintf(fp, " timerid=%d", si->si_timerid);
fprintf(fp, " overrun=%d", si->si_overrun);
if (si->si_errno != 0)
fprintf(fp, " errno=%d", si->si_errno);
break;
case SI_ASYNCIO:
fprintf(fp, " value=%p", si->si_value.sival_ptr);
break;
case SI_MESGQ:
fprintf(fp, " value=%p", si->si_value.sival_ptr);
fprintf(fp, " mqd=%d", si->si_mqd);
break;
default:
switch (si->si_signo) {
case SIGILL:
case SIGFPE:
case SIGSEGV:
case SIGBUS:
fprintf(fp, " trapno=%d", si->si_trapno);
fprintf(fp, " addr=%p", si->si_addr);
break;
case SIGCHLD:
fprintf(fp, " pid=%jd uid=%jd", (intmax_t)si->si_pid,
(intmax_t)si->si_uid);
fprintf(fp, " status=%d", si->si_status);
break;
}
}
}
static void
report_signal(struct trussinfo *info, siginfo_t *si, struct ptrace_lwpinfo *pl)
{
struct threadinfo *t;
const char *signame;
t = info->curthread;
clock_gettime(CLOCK_REALTIME, &t->after);
print_line_prefix(info);
signame = sysdecode_signal(si->si_status);
if (signame == NULL)
signame = "?";
fprintf(info->outfile, "SIGNAL %u (%s)", si->si_status, signame);
if (pl->pl_event == PL_EVENT_SIGNAL && pl->pl_flags & PL_FLAG_SI)
decode_siginfo(info->outfile, &pl->pl_siginfo);
fprintf(info->outfile, "\n");
}
/*
* Wait for events until all the processes have exited or truss has been
* asked to stop.
*/
void
eventloop(struct trussinfo *info)
{
struct ptrace_lwpinfo pl;
siginfo_t si;
int pending_signal;
while (!LIST_EMPTY(&info->proclist)) {
if (detaching) {
detach_all_procs(info);
return;
}
if (waitid(P_ALL, 0, &si, WTRAPPED | WEXITED) == -1) {
if (errno == EINTR)
continue;
err(1, "Unexpected error from waitid");
}
assert(si.si_signo == SIGCHLD);
switch (si.si_code) {
case CLD_EXITED:
case CLD_KILLED:
case CLD_DUMPED:
find_exit_thread(info, si.si_pid);
if ((info->flags & COUNTONLY) == 0) {
if (si.si_code == CLD_EXITED)
thread_exit_syscall(info);
report_exit(info, &si);
}
free_proc(info->curthread->proc);
info->curthread = NULL;
break;
case CLD_TRAPPED:
if (ptrace(PT_LWPINFO, si.si_pid, (caddr_t)&pl,
sizeof(pl)) == -1)
err(1, "ptrace(PT_LWPINFO)");
if (pl.pl_flags & PL_FLAG_CHILD) {
new_proc(info, si.si_pid, pl.pl_lwpid);
assert(LIST_FIRST(&info->proclist)->abi !=
NULL);
} else if (pl.pl_flags & PL_FLAG_BORN)
new_thread(find_proc(info, si.si_pid),
pl.pl_lwpid);
find_thread(info, si.si_pid, pl.pl_lwpid);
if (si.si_status == SIGTRAP &&
(pl.pl_flags & (PL_FLAG_BORN|PL_FLAG_EXITED|
PL_FLAG_SCE|PL_FLAG_SCX)) != 0) {
if (pl.pl_flags & PL_FLAG_BORN) {
if ((info->flags & COUNTONLY) == 0)
report_thread_birth(info);
} else if (pl.pl_flags & PL_FLAG_EXITED) {
if ((info->flags & COUNTONLY) == 0)
report_thread_death(info);
free_thread(info->curthread);
info->curthread = NULL;
} else if (pl.pl_flags & PL_FLAG_SCE)
enter_syscall(info, info->curthread, &pl);
else if (pl.pl_flags & PL_FLAG_SCX)
exit_syscall(info, &pl);
pending_signal = 0;
} else if (pl.pl_flags & PL_FLAG_CHILD) {
if ((info->flags & COUNTONLY) == 0)
report_new_child(info);
pending_signal = 0;
} else {
if ((info->flags & NOSIGS) == 0)
report_signal(info, &si, &pl);
pending_signal = si.si_status;
}
ptrace(PT_SYSCALL, si.si_pid, (caddr_t)1,
pending_signal);
break;
case CLD_STOPPED:
errx(1, "waitid reported CLD_STOPPED");
case CLD_CONTINUED:
break;
}
}
}