freebsd-dev/sbin/hastd/hooks.c

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