391 lines
9.3 KiB
C
391 lines
9.3 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2010 The FreeBSD Foundation
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* Copyright (c) 2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
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* All rights reserved.
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*
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* This software was developed by Pawel Jakub Dawidek under sponsorship from
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* the FreeBSD Foundation.
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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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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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#include <sys/types.h>
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#include <sys/sysctl.h>
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#include <sys/wait.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <paths.h>
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#include <signal.h>
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#include <stdbool.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 <syslog.h>
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#include <unistd.h>
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#include <pjdlog.h>
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#include "hooks.h"
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#include "subr.h"
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#include "synch.h"
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/* Report processes that are running for too long not often than this value. */
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#define REPORT_INTERVAL 60
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/* Are we initialized? */
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static bool hooks_initialized = false;
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/*
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* Keep all processes we forked on a global queue, so we can report nicely
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* when they finish or report that they are running for a long time.
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*/
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#define HOOKPROC_MAGIC_ALLOCATED 0x80090ca
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#define HOOKPROC_MAGIC_ONLIST 0x80090c0
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struct hookproc {
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/* Magic. */
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int hp_magic;
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/* PID of a forked child. */
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pid_t hp_pid;
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/* When process were forked? */
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time_t hp_birthtime;
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/* When we logged previous reported? */
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time_t hp_lastreport;
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/* Path to executable and all the arguments we passed. */
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char hp_comm[PATH_MAX];
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TAILQ_ENTRY(hookproc) hp_next;
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};
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static TAILQ_HEAD(, hookproc) hookprocs;
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static pthread_mutex_t hookprocs_lock;
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static void hook_remove(struct hookproc *hp);
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static void hook_free(struct hookproc *hp);
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static void
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descriptors(void)
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{
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int fd;
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/*
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* Close all (or almost all) descriptors.
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*/
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if (pjdlog_mode_get() == PJDLOG_MODE_STD) {
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closefrom(MAX(MAX(STDIN_FILENO, STDOUT_FILENO),
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STDERR_FILENO) + 1);
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return;
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}
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closefrom(0);
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/*
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* Redirect stdin, stdout and stderr to /dev/null.
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*/
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fd = open(_PATH_DEVNULL, O_RDONLY);
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if (fd == -1) {
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pjdlog_errno(LOG_WARNING, "Unable to open %s for reading",
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_PATH_DEVNULL);
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} else if (fd != STDIN_FILENO) {
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if (dup2(fd, STDIN_FILENO) == -1) {
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pjdlog_errno(LOG_WARNING,
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"Unable to duplicate descriptor for stdin");
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}
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close(fd);
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}
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fd = open(_PATH_DEVNULL, O_WRONLY);
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if (fd == -1) {
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pjdlog_errno(LOG_WARNING, "Unable to open %s for writing",
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_PATH_DEVNULL);
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} else {
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if (fd != STDOUT_FILENO && dup2(fd, STDOUT_FILENO) == -1) {
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pjdlog_errno(LOG_WARNING,
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"Unable to duplicate descriptor for stdout");
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}
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if (fd != STDERR_FILENO && dup2(fd, STDERR_FILENO) == -1) {
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pjdlog_errno(LOG_WARNING,
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"Unable to duplicate descriptor for stderr");
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}
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if (fd != STDOUT_FILENO && fd != STDERR_FILENO)
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close(fd);
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}
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}
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void
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hook_init(void)
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{
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PJDLOG_ASSERT(!hooks_initialized);
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mtx_init(&hookprocs_lock);
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TAILQ_INIT(&hookprocs);
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hooks_initialized = true;
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}
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void
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hook_fini(void)
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{
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struct hookproc *hp;
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PJDLOG_ASSERT(hooks_initialized);
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mtx_lock(&hookprocs_lock);
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while ((hp = TAILQ_FIRST(&hookprocs)) != NULL) {
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PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ONLIST);
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PJDLOG_ASSERT(hp->hp_pid > 0);
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hook_remove(hp);
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hook_free(hp);
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}
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mtx_unlock(&hookprocs_lock);
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mtx_destroy(&hookprocs_lock);
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TAILQ_INIT(&hookprocs);
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hooks_initialized = false;
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}
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static struct hookproc *
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hook_alloc(const char *path, char **args)
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{
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struct hookproc *hp;
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unsigned int ii;
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hp = malloc(sizeof(*hp));
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if (hp == NULL) {
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pjdlog_error("Unable to allocate %zu bytes of memory for a hook.",
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sizeof(*hp));
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return (NULL);
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}
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hp->hp_pid = 0;
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hp->hp_birthtime = hp->hp_lastreport = time(NULL);
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(void)strlcpy(hp->hp_comm, path, sizeof(hp->hp_comm));
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/* We start at 2nd argument as we don't want to have exec name twice. */
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for (ii = 1; args[ii] != NULL; ii++) {
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(void)snprlcat(hp->hp_comm, sizeof(hp->hp_comm), " %s",
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args[ii]);
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}
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if (strlen(hp->hp_comm) >= sizeof(hp->hp_comm) - 1) {
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pjdlog_error("Exec path too long, correct configuration file.");
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free(hp);
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return (NULL);
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}
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hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED;
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return (hp);
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}
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static void
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hook_add(struct hookproc *hp, pid_t pid)
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{
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PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED);
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PJDLOG_ASSERT(hp->hp_pid == 0);
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hp->hp_pid = pid;
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mtx_lock(&hookprocs_lock);
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hp->hp_magic = HOOKPROC_MAGIC_ONLIST;
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TAILQ_INSERT_TAIL(&hookprocs, hp, hp_next);
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mtx_unlock(&hookprocs_lock);
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}
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static void
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hook_remove(struct hookproc *hp)
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{
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PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ONLIST);
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PJDLOG_ASSERT(hp->hp_pid > 0);
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PJDLOG_ASSERT(mtx_owned(&hookprocs_lock));
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TAILQ_REMOVE(&hookprocs, hp, hp_next);
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hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED;
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}
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static void
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hook_free(struct hookproc *hp)
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{
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PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED);
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PJDLOG_ASSERT(hp->hp_pid > 0);
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hp->hp_magic = 0;
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free(hp);
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}
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static struct hookproc *
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hook_find(pid_t pid)
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{
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struct hookproc *hp;
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PJDLOG_ASSERT(mtx_owned(&hookprocs_lock));
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TAILQ_FOREACH(hp, &hookprocs, hp_next) {
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PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ONLIST);
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PJDLOG_ASSERT(hp->hp_pid > 0);
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if (hp->hp_pid == pid)
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break;
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}
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return (hp);
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}
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void
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hook_check_one(pid_t pid, int status)
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{
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struct hookproc *hp;
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mtx_lock(&hookprocs_lock);
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hp = hook_find(pid);
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if (hp == NULL) {
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mtx_unlock(&hookprocs_lock);
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pjdlog_debug(1, "Unknown process pid=%u", pid);
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return;
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}
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hook_remove(hp);
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mtx_unlock(&hookprocs_lock);
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if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
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pjdlog_debug(1, "Hook exited gracefully (pid=%u, cmd=[%s]).",
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pid, hp->hp_comm);
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} else if (WIFSIGNALED(status)) {
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pjdlog_error("Hook was killed (pid=%u, signal=%d, cmd=[%s]).",
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pid, WTERMSIG(status), hp->hp_comm);
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} else {
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pjdlog_error("Hook exited ungracefully (pid=%u, exitcode=%d, cmd=[%s]).",
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pid, WIFEXITED(status) ? WEXITSTATUS(status) : -1,
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hp->hp_comm);
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}
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hook_free(hp);
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}
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void
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hook_check(void)
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{
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struct hookproc *hp, *hp2;
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time_t now;
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PJDLOG_ASSERT(hooks_initialized);
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pjdlog_debug(2, "Checking hooks.");
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/*
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* Report about processes that are running for a long time.
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*/
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now = time(NULL);
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mtx_lock(&hookprocs_lock);
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TAILQ_FOREACH_SAFE(hp, &hookprocs, hp_next, hp2) {
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PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ONLIST);
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PJDLOG_ASSERT(hp->hp_pid > 0);
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/*
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* If process doesn't exists we somehow missed it.
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* Not much can be done expect for logging this situation.
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*/
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if (kill(hp->hp_pid, 0) == -1 && errno == ESRCH) {
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pjdlog_warning("Hook disappeared (pid=%u, cmd=[%s]).",
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hp->hp_pid, hp->hp_comm);
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hook_remove(hp);
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hook_free(hp);
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continue;
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}
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/*
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* Skip processes younger than 1 minute.
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*/
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if (now - hp->hp_lastreport < REPORT_INTERVAL)
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continue;
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/*
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* Hook is running for too long, report it.
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*/
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pjdlog_warning("Hook is running for %ju seconds (pid=%u, cmd=[%s]).",
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(uintmax_t)(now - hp->hp_birthtime), hp->hp_pid,
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hp->hp_comm);
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hp->hp_lastreport = now;
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}
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mtx_unlock(&hookprocs_lock);
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}
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void
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hook_exec(const char *path, ...)
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{
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va_list ap;
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va_start(ap, path);
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hook_execv(path, ap);
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va_end(ap);
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}
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void
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hook_execv(const char *path, va_list ap)
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{
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struct hookproc *hp;
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char *args[64];
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unsigned int ii;
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sigset_t mask;
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pid_t pid;
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PJDLOG_ASSERT(hooks_initialized);
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if (path == NULL || path[0] == '\0')
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return;
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memset(args, 0, sizeof(args));
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args[0] = __DECONST(char *, path);
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for (ii = 1; ii < sizeof(args) / sizeof(args[0]); ii++) {
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args[ii] = va_arg(ap, char *);
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if (args[ii] == NULL)
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break;
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}
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PJDLOG_ASSERT(ii < sizeof(args) / sizeof(args[0]));
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hp = hook_alloc(path, args);
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if (hp == NULL)
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return;
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pjdlog_debug(1, "Executing hook: %s", hp->hp_comm);
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pid = fork();
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switch (pid) {
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case -1: /* Error. */
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pjdlog_errno(LOG_ERR, "Unable to fork to execute %s", path);
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hook_free(hp);
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return;
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case 0: /* Child. */
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descriptors();
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PJDLOG_VERIFY(sigemptyset(&mask) == 0);
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PJDLOG_VERIFY(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
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/*
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* Dummy handler set for SIGCHLD in the parent will be restored
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* to SIG_IGN on execv(3) below, so there is no need to do
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* anything with it.
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*/
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execv(path, args);
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pjdlog_errno(LOG_ERR, "Unable to execute %s", path);
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exit(EX_SOFTWARE);
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default: /* Parent. */
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hook_add(hp, pid);
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break;
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}
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}
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