6c61b0f324
This is done by changing get_syscall() to either lookup the known syscall or add it into the list with the default handlers for printing. This also simplifies some code to not have to check if the syscall variable is set or NULL. Reviewed by: jhb Relnotes: yes Differential Revision: https://reviews.freebsd.org/D3792
596 lines
15 KiB
C
596 lines
15 KiB
C
/*-
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* Copyright 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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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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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#include <sys/ptrace.h>
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#include <sys/sysctl.h>
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#include <sys/wait.h>
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#include <assert.h>
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#include <err.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdint.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 <time.h>
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#include <unistd.h>
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#include "truss.h"
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#include "syscall.h"
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#include "extern.h"
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SET_DECLARE(procabi, struct procabi);
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static sig_atomic_t detaching;
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static void new_proc(struct trussinfo *, pid_t);
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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 fork(), enable tracing in the child, and then exec the given
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* command. At that point, the child process stops, and the parent
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* can wake up and deal with it.
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*/
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void
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setup_and_wait(struct trussinfo *info, char *command[])
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{
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pid_t pid;
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pid = vfork();
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if (pid == -1)
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err(1, "fork failed");
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if (pid == 0) { /* Child */
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ptrace(PT_TRACE_ME, 0, 0, 0);
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execvp(command[0], command);
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err(1, "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, 0) < 0)
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err(1, "unexpect stop in waitpid");
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new_proc(info, pid);
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}
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/*
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* start_tracing is called to attach to an existing process.
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*/
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void
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start_tracing(struct trussinfo *info, pid_t pid)
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{
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int ret, retry;
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retry = 10;
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do {
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ret = ptrace(PT_ATTACH, pid, NULL, 0);
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usleep(200);
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} while (ret && retry-- > 0);
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if (ret)
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err(1, "can not attach to target process");
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if (waitpid(pid, NULL, 0) < 0)
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err(1, "Unexpect stop in waitpid");
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new_proc(info, pid);
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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 __unused)
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{
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detaching = 1;
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}
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static void
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detach_proc(pid_t pid)
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{
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/* stop the child so that we can detach */
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kill(pid, SIGSTOP);
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if (waitpid(pid, NULL, 0) < 0)
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err(1, "Unexpected stop in waitpid");
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if (ptrace(PT_DETACH, pid, (caddr_t)1, 0) < 0)
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err(1, "Can not detach the process");
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kill(pid, SIGCONT);
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}
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/*
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* Determine the ABI. This is called after every exec, and when
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* a process is first monitored.
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*/
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static struct procabi *
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find_abi(pid_t pid)
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{
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struct procabi **pabi;
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size_t len;
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int error;
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int mib[4];
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char progt[32];
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len = sizeof(progt);
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mib[0] = CTL_KERN;
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mib[1] = KERN_PROC;
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mib[2] = KERN_PROC_SV_NAME;
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mib[3] = pid;
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error = sysctl(mib, 4, progt, &len, NULL, 0);
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if (error != 0)
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err(2, "can not get sysvec name");
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SET_FOREACH(pabi, procabi) {
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if (strcmp((*pabi)->type, progt) == 0)
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return (*pabi);
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}
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warnx("ABI %s for pid %ld is not supported", progt, (long)pid);
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return (NULL);
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}
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static void
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new_proc(struct trussinfo *info, pid_t pid)
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{
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struct procinfo *np;
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/*
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* If this happens it means there is a bug in truss. Unfortunately
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* this will kill any processes are attached to.
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*/
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LIST_FOREACH(np, &info->proclist, entries) {
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if (np->pid == pid)
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errx(1, "Duplicate process for pid %ld", (long)pid);
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}
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if (info->flags & FOLLOWFORKS)
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if (ptrace(PT_FOLLOW_FORK, pid, NULL, 1) == -1)
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err(1, "Unable to follow forks for pid %ld", (long)pid);
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np = calloc(1, sizeof(struct procinfo));
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np->pid = pid;
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np->abi = find_abi(pid);
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SLIST_INIT(&np->threadlist);
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LIST_INSERT_HEAD(&info->proclist, np, entries);
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}
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static void
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free_proc(struct procinfo *p)
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{
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struct threadinfo *t, *t2;
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SLIST_FOREACH_SAFE(t, &p->threadlist, entries, t2) {
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free(t);
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}
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LIST_REMOVE(p, entries);
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free(p);
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}
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static void
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detach_all_procs(struct trussinfo *info)
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{
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struct procinfo *p, *p2;
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LIST_FOREACH_SAFE(p, &info->proclist, entries, p2) {
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detach_proc(p->pid);
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free_proc(p);
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}
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}
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static struct procinfo *
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find_proc(struct trussinfo *info, pid_t pid)
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{
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struct procinfo *np;
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LIST_FOREACH(np, &info->proclist, entries) {
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if (np->pid == pid)
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return (np);
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}
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return (NULL);
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}
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/*
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* Change curthread member based on (pid, lwpid).
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* If it is a new thread, create a threadinfo structure.
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*/
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static void
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find_thread(struct trussinfo *info, pid_t pid, lwpid_t lwpid)
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{
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struct procinfo *np;
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struct threadinfo *nt;
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np = find_proc(info, pid);
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assert(np != NULL);
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SLIST_FOREACH(nt, &np->threadlist, entries) {
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if (nt->tid == lwpid) {
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info->curthread = nt;
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return;
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}
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}
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nt = calloc(1, sizeof(struct threadinfo));
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if (nt == NULL)
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err(1, "calloc() failed");
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nt->proc = np;
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nt->tid = lwpid;
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SLIST_INSERT_HEAD(&np->threadlist, nt, entries);
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info->curthread = nt;
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}
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/*
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* When a process exits, it no longer has any threads left. However,
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* the main loop expects a valid curthread. In cases when a thread
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* triggers the termination (e.g. calling exit or triggering a fault)
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* we would ideally use that thread. However, if a process is killed
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* by a signal sent from another process then there is no "correct"
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* thread. We just punt and use the first thread.
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*/
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static void
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find_exit_thread(struct trussinfo *info, pid_t pid)
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{
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struct procinfo *np;
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struct threadinfo *nt;
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np = find_proc(info, pid);
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assert(np != NULL);
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if (SLIST_EMPTY(&np->threadlist)) {
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/*
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* If an existing process exits right after we attach
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* to it but before it posts any events, there won't
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* be any threads. Create a dummy thread and set its
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* "before" time to the global start time.
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*/
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nt = calloc(1, sizeof(struct threadinfo));
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if (nt == NULL)
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err(1, "calloc() failed");
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nt->proc = np;
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nt->tid = 0;
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SLIST_INSERT_HEAD(&np->threadlist, nt, entries);
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nt->before = info->start_time;
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}
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info->curthread = SLIST_FIRST(&np->threadlist);
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}
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static void
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alloc_syscall(struct threadinfo *t, struct ptrace_lwpinfo *pl)
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{
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u_int i;
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assert(t->in_syscall == 0);
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assert(t->cs.number == 0);
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assert(t->cs.name == NULL);
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assert(t->cs.nargs == 0);
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for (i = 0; i < nitems(t->cs.s_args); i++)
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assert(t->cs.s_args[i] == NULL);
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memset(t->cs.args, 0, sizeof(t->cs.args));
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t->cs.number = pl->pl_syscall_code;
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t->in_syscall = 1;
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}
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static void
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free_syscall(struct threadinfo *t)
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{
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u_int i;
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for (i = 0; i < t->cs.nargs; i++)
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free(t->cs.s_args[i]);
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memset(&t->cs, 0, sizeof(t->cs));
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t->in_syscall = 0;
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}
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static void
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enter_syscall(struct trussinfo *info, struct ptrace_lwpinfo *pl)
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{
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struct threadinfo *t;
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struct syscall *sc;
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u_int i, narg;
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t = info->curthread;
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alloc_syscall(t, pl);
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narg = MIN(pl->pl_syscall_narg, nitems(t->cs.args));
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if (narg != 0 && t->proc->abi->fetch_args(info, narg) != 0) {
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free_syscall(t);
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return;
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}
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if (t->cs.number >= 0 && t->cs.number < t->proc->abi->nsyscalls)
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t->cs.name = t->proc->abi->syscallnames[t->cs.number];
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if (t->cs.name == NULL)
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fprintf(info->outfile, "-- UNKNOWN %s SYSCALL %d --\n",
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t->proc->abi->type, t->cs.number);
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sc = get_syscall(t->cs.name, narg);
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t->cs.nargs = sc->nargs;
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assert(sc->nargs <= nitems(t->cs.s_args));
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t->cs.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 (t->cs.name != NULL) {
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#if DEBUG
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fprintf(stderr, "syscall %s(", t->cs.name);
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#endif
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for (i = 0; i < t->cs.nargs; i++) {
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#if DEBUG
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fprintf(stderr, "0x%lx%s", sc ?
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t->cs.args[sc->args[i].offset] : t->cs.args[i],
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i < (t->cs.nargs - 1) ? "," : "");
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#endif
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if (!(sc->args[i].type & OUT)) {
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t->cs.s_args[i] = print_arg(&sc->args[i],
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t->cs.args, 0, info);
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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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clock_gettime(CLOCK_REALTIME, &t->before);
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}
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static void
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exit_syscall(struct trussinfo *info, struct ptrace_lwpinfo *pl)
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{
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struct threadinfo *t;
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struct procinfo *p;
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struct syscall *sc;
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long retval[2];
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u_int i;
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int errorp;
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t = info->curthread;
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if (!t->in_syscall)
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return;
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clock_gettime(CLOCK_REALTIME, &t->after);
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p = t->proc;
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if (p->abi->fetch_retval(info, retval, &errorp) < 0) {
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free_syscall(t);
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return;
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}
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sc = t->cs.sc;
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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 enter_syscall().
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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, then don't bother
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* getting the data; it may not be valid.
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*/
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if (errorp) {
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asprintf(&temp, "0x%lx",
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t->cs.args[sc->args[i].offset]);
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} else {
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temp = print_arg(&sc->args[i],
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t->cs.args, retval, info);
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}
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t->cs.s_args[i] = temp;
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}
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}
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print_syscall_ret(info, t->cs.name, t->cs.nargs, t->cs.s_args,
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errorp, retval, sc);
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free_syscall(t);
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/*
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* If the process executed a new image, check the ABI. If the
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* new ABI isn't supported, stop tracing this process.
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*/
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if (pl->pl_flags & PL_FLAG_EXEC) {
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p->abi = find_abi(p->pid);
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if (p->abi == NULL) {
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if (ptrace(PT_DETACH, p->pid, (caddr_t)1, 0) < 0)
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err(1, "Can not detach the process");
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free_proc(p);
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}
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}
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}
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static void
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report_exit(struct trussinfo *info, siginfo_t *si)
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{
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struct timespec timediff;
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if (info->flags & FOLLOWFORKS)
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fprintf(info->outfile, "%5d: ", si->si_pid);
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clock_gettime(CLOCK_REALTIME, &info->curthread->after);
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if (info->flags & ABSOLUTETIMESTAMPS) {
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timespecsubt(&info->curthread->after, &info->start_time,
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&timediff);
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fprintf(info->outfile, "%jd.%09ld ", (intmax_t)timediff.tv_sec,
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timediff.tv_nsec);
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}
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if (info->flags & RELATIVETIMESTAMPS) {
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timespecsubt(&info->curthread->after, &info->curthread->before,
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&timediff);
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fprintf(info->outfile, "%jd.%09ld ", (intmax_t)timediff.tv_sec,
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timediff.tv_nsec);
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}
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if (si->si_code == CLD_EXITED)
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fprintf(info->outfile, "process exit, rval = %u\n",
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si->si_status);
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else
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fprintf(info->outfile, "process killed, signal = %u%s\n",
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si->si_status, si->si_code == CLD_DUMPED ?
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" (core dumped)" : "");
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}
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static void
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report_new_child(struct trussinfo *info, pid_t pid)
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{
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struct timespec timediff;
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clock_gettime(CLOCK_REALTIME, &info->curthread->after);
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assert(info->flags & FOLLOWFORKS);
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fprintf(info->outfile, "%5d: ", pid);
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if (info->flags & ABSOLUTETIMESTAMPS) {
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timespecsubt(&info->curthread->after, &info->start_time,
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&timediff);
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fprintf(info->outfile, "%jd.%09ld ", (intmax_t)timediff.tv_sec,
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timediff.tv_nsec);
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}
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if (info->flags & RELATIVETIMESTAMPS) {
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timediff.tv_sec = 0;
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timediff.tv_nsec = 0;
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fprintf(info->outfile, "%jd.%09ld ", (intmax_t)timediff.tv_sec,
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timediff.tv_nsec);
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}
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fprintf(info->outfile, "<new process>\n");
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}
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static void
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report_signal(struct trussinfo *info, siginfo_t *si)
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{
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struct timespec timediff;
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char *signame;
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if (info->flags & FOLLOWFORKS)
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fprintf(info->outfile, "%5d: ", si->si_pid);
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if (info->flags & ABSOLUTETIMESTAMPS) {
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timespecsubt(&info->curthread->after, &info->start_time,
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&timediff);
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fprintf(info->outfile, "%jd.%09ld ", (intmax_t)timediff.tv_sec,
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timediff.tv_nsec);
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}
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if (info->flags & RELATIVETIMESTAMPS) {
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timespecsubt(&info->curthread->after, &info->curthread->before,
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&timediff);
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fprintf(info->outfile, "%jd.%09ld ", (intmax_t)timediff.tv_sec,
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timediff.tv_nsec);
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}
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signame = strsig(si->si_status);
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fprintf(info->outfile, "SIGNAL %u (%s)\n", si->si_status,
|
|
signame == NULL ? "?" : signame);
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
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);
|
|
assert(LIST_FIRST(&info->proclist)->abi !=
|
|
NULL);
|
|
}
|
|
find_thread(info, si.si_pid, pl.pl_lwpid);
|
|
|
|
if (si.si_status == SIGTRAP) {
|
|
if (pl.pl_flags & PL_FLAG_SCE)
|
|
enter_syscall(info, &pl);
|
|
else if (pl.pl_flags & PL_FLAG_SCX)
|
|
exit_syscall(info, &pl);
|
|
else
|
|
errx(1,
|
|
"pl_flags %x contains neither PL_FLAG_SCE nor PL_FLAG_SCX",
|
|
pl.pl_flags);
|
|
pending_signal = 0;
|
|
} else if (pl.pl_flags & PL_FLAG_CHILD) {
|
|
if ((info->flags & COUNTONLY) == 0)
|
|
report_new_child(info, si.si_pid);
|
|
pending_signal = 0;
|
|
} else {
|
|
if ((info->flags & NOSIGS) == 0)
|
|
report_signal(info, &si);
|
|
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;
|
|
}
|
|
}
|
|
}
|