hooks.c revision 211885
1204076Spjd/*- 2204076Spjd * Copyright (c) 2010 The FreeBSD Foundation 3211885Spjd * Copyright (c) 2010 Pawel Jakub Dawidek <pjd@FreeBSD.org> 4204076Spjd * All rights reserved. 5204076Spjd * 6204076Spjd * This software was developed by Pawel Jakub Dawidek under sponsorship from 7204076Spjd * the FreeBSD Foundation. 8204076Spjd * 9204076Spjd * Redistribution and use in source and binary forms, with or without 10204076Spjd * modification, are permitted provided that the following conditions 11204076Spjd * are met: 12204076Spjd * 1. Redistributions of source code must retain the above copyright 13204076Spjd * notice, this list of conditions and the following disclaimer. 14204076Spjd * 2. Redistributions in binary form must reproduce the above copyright 15204076Spjd * notice, this list of conditions and the following disclaimer in the 16204076Spjd * documentation and/or other materials provided with the distribution. 17204076Spjd * 18204076Spjd * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 19204076Spjd * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20204076Spjd * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21204076Spjd * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 22204076Spjd * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23204076Spjd * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24204076Spjd * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25204076Spjd * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26204076Spjd * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27204076Spjd * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28204076Spjd * SUCH DAMAGE. 29204076Spjd */ 30204076Spjd 31204076Spjd#include <sys/cdefs.h> 32204076Spjd__FBSDID("$FreeBSD: head/sbin/hastd/hooks.c 211885 2010-08-27 14:38:12Z pjd $"); 33204076Spjd 34204076Spjd#include <sys/types.h> 35211885Spjd#include <sys/sysctl.h> 36204076Spjd#include <sys/wait.h> 37204076Spjd 38204076Spjd#include <assert.h> 39211885Spjd#include <errno.h> 40204076Spjd#include <fcntl.h> 41211885Spjd#include <libgen.h> 42211885Spjd#include <paths.h> 43211885Spjd#include <signal.h> 44211885Spjd#include <stdbool.h> 45211885Spjd#include <stdint.h> 46204076Spjd#include <stdio.h> 47204076Spjd#include <stdlib.h> 48204076Spjd#include <string.h> 49204076Spjd#include <syslog.h> 50211885Spjd#include <unistd.h> 51204076Spjd 52204076Spjd#include <pjdlog.h> 53204076Spjd 54204076Spjd#include "hooks.h" 55211885Spjd#include "synch.h" 56204076Spjd 57211885Spjd/* Report processes that are running for too long not often than this value. */ 58211885Spjd#define REPORT_INTERVAL 60 59211885Spjd 60211885Spjd/* Are we initialized? */ 61211885Spjdstatic bool hooks_initialized = false; 62211885Spjd 63211885Spjd/* 64211885Spjd * Keep all processes we forked on a global queue, so we can report nicely 65211885Spjd * when they finish or report that they are running for a long time. 66211885Spjd */ 67211885Spjd#define HOOKPROC_MAGIC_ALLOCATED 0x80090ca 68211885Spjd#define HOOKPROC_MAGIC_ONLIST 0x80090c0 69211885Spjdstruct hookproc { 70211885Spjd /* Magic. */ 71211885Spjd int hp_magic; 72211885Spjd /* PID of a forked child. */ 73211885Spjd pid_t hp_pid; 74211885Spjd /* When process were forked? */ 75211885Spjd time_t hp_birthtime; 76211885Spjd /* When we logged previous reported? */ 77211885Spjd time_t hp_lastreport; 78211885Spjd /* Path to executable and all the arguments we passed. */ 79211885Spjd char hp_comm[PATH_MAX]; 80211885Spjd TAILQ_ENTRY(hookproc) hp_next; 81211885Spjd}; 82211885Spjdstatic TAILQ_HEAD(, hookproc) hookprocs; 83211885Spjdstatic pthread_mutex_t hookprocs_lock; 84211885Spjd 85204076Spjdstatic void 86204076Spjddescriptors(void) 87204076Spjd{ 88204076Spjd long maxfd; 89204076Spjd int fd; 90204076Spjd 91204076Spjd /* 92204076Spjd * Close all descriptors. 93204076Spjd */ 94204076Spjd maxfd = sysconf(_SC_OPEN_MAX); 95204076Spjd if (maxfd < 0) { 96204076Spjd pjdlog_errno(LOG_WARNING, "sysconf(_SC_OPEN_MAX) failed"); 97204076Spjd maxfd = 1024; 98204076Spjd } 99211884Spjd for (fd = 0; fd <= maxfd; fd++) { 100211884Spjd switch (fd) { 101211884Spjd case STDIN_FILENO: 102211884Spjd case STDOUT_FILENO: 103211884Spjd case STDERR_FILENO: 104211884Spjd if (pjdlog_mode_get() == PJDLOG_MODE_STD) 105211884Spjd break; 106211884Spjd /* FALLTHROUGH */ 107211884Spjd default: 108211884Spjd close(fd); 109211884Spjd break; 110211884Spjd } 111211884Spjd } 112211884Spjd if (pjdlog_mode_get() == PJDLOG_MODE_STD) 113211884Spjd return; 114204076Spjd /* 115204076Spjd * Redirect stdin, stdout and stderr to /dev/null. 116204076Spjd */ 117204076Spjd fd = open(_PATH_DEVNULL, O_RDONLY); 118204076Spjd if (fd < 0) { 119204076Spjd pjdlog_errno(LOG_WARNING, "Unable to open %s for reading", 120204076Spjd _PATH_DEVNULL); 121204076Spjd } else if (fd != STDIN_FILENO) { 122204076Spjd if (dup2(fd, STDIN_FILENO) < 0) { 123204076Spjd pjdlog_errno(LOG_WARNING, 124204076Spjd "Unable to duplicate descriptor for stdin"); 125204076Spjd } 126204076Spjd close(fd); 127204076Spjd } 128204076Spjd fd = open(_PATH_DEVNULL, O_WRONLY); 129204076Spjd if (fd < 0) { 130204076Spjd pjdlog_errno(LOG_WARNING, "Unable to open %s for writing", 131204076Spjd _PATH_DEVNULL); 132204076Spjd } else { 133204076Spjd if (fd != STDOUT_FILENO && dup2(fd, STDOUT_FILENO) < 0) { 134204076Spjd pjdlog_errno(LOG_WARNING, 135204076Spjd "Unable to duplicate descriptor for stdout"); 136204076Spjd } 137204076Spjd if (fd != STDERR_FILENO && dup2(fd, STDERR_FILENO) < 0) { 138204076Spjd pjdlog_errno(LOG_WARNING, 139204076Spjd "Unable to duplicate descriptor for stderr"); 140204076Spjd } 141204076Spjd if (fd != STDOUT_FILENO && fd != STDERR_FILENO) 142204076Spjd close(fd); 143204076Spjd } 144204076Spjd} 145204076Spjd 146211885Spjdvoid 147211885Spjdhook_init(void) 148211885Spjd{ 149211885Spjd 150211885Spjd mtx_init(&hookprocs_lock); 151211885Spjd TAILQ_INIT(&hookprocs); 152211885Spjd hooks_initialized = true; 153211885Spjd} 154211885Spjd 155211885Spjdstatic struct hookproc * 156211885Spjdhook_alloc(const char *path, char **args) 157211885Spjd{ 158211885Spjd struct hookproc *hp; 159211885Spjd unsigned int ii; 160211885Spjd 161211885Spjd hp = malloc(sizeof(*hp)); 162211885Spjd if (hp == NULL) { 163211885Spjd pjdlog_error("Unable to allocate %zu bytes of memory for a hook.", 164211885Spjd sizeof(*hp)); 165211885Spjd return (NULL); 166211885Spjd } 167211885Spjd 168211885Spjd hp->hp_pid = 0; 169211885Spjd hp->hp_birthtime = hp->hp_lastreport = time(NULL); 170211885Spjd (void)strlcpy(hp->hp_comm, path, sizeof(hp->hp_comm)); 171211885Spjd /* We start at 2nd argument as we don't want to have exec name twice. */ 172211885Spjd for (ii = 1; args[ii] != NULL; ii++) { 173211885Spjd (void)strlcat(hp->hp_comm, " ", sizeof(hp->hp_comm)); 174211885Spjd (void)strlcat(hp->hp_comm, args[ii], sizeof(hp->hp_comm)); 175211885Spjd } 176211885Spjd if (strlen(hp->hp_comm) >= sizeof(hp->hp_comm) - 1) { 177211885Spjd pjdlog_error("Exec path too long, correct configuration file."); 178211885Spjd free(hp); 179211885Spjd return (NULL); 180211885Spjd } 181211885Spjd hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 182211885Spjd return (hp); 183211885Spjd} 184211885Spjd 185211885Spjdstatic void 186211885Spjdhook_add(struct hookproc *hp, pid_t pid) 187211885Spjd{ 188211885Spjd 189211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 190211885Spjd assert(hp->hp_pid == 0); 191211885Spjd 192211885Spjd hp->hp_pid = pid; 193211885Spjd mtx_lock(&hookprocs_lock); 194211885Spjd hp->hp_magic = HOOKPROC_MAGIC_ONLIST; 195211885Spjd TAILQ_INSERT_TAIL(&hookprocs, hp, hp_next); 196211885Spjd mtx_unlock(&hookprocs_lock); 197211885Spjd} 198211885Spjd 199211885Spjdstatic void 200211885Spjdhook_remove(struct hookproc *hp) 201211885Spjd{ 202211885Spjd 203211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 204211885Spjd assert(hp->hp_pid > 0); 205211885Spjd assert(mtx_owned(&hookprocs_lock)); 206211885Spjd 207211885Spjd TAILQ_REMOVE(&hookprocs, hp, hp_next); 208211885Spjd hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 209211885Spjd} 210211885Spjd 211211885Spjdstatic void 212211885Spjdhook_free(struct hookproc *hp) 213211885Spjd{ 214211885Spjd 215211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 216211885Spjd assert(hp->hp_pid > 0); 217211885Spjd 218211885Spjd hp->hp_magic = 0; 219211885Spjd free(hp); 220211885Spjd} 221211885Spjd 222211885Spjdstatic struct hookproc * 223211885Spjdhook_find(pid_t pid) 224211885Spjd{ 225211885Spjd struct hookproc *hp; 226211885Spjd 227211885Spjd assert(mtx_owned(&hookprocs_lock)); 228211885Spjd 229211885Spjd TAILQ_FOREACH(hp, &hookprocs, hp_next) { 230211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 231211885Spjd assert(hp->hp_pid > 0); 232211885Spjd 233211885Spjd if (hp->hp_pid == pid) 234211885Spjd break; 235211885Spjd } 236211885Spjd 237211885Spjd return (hp); 238211885Spjd} 239211885Spjd 240211885Spjdvoid 241211885Spjdhook_check(bool sigchld) 242211885Spjd{ 243211885Spjd struct hookproc *hp, *hp2; 244211885Spjd int status; 245211885Spjd time_t now; 246211885Spjd pid_t pid; 247211885Spjd 248211885Spjd assert(hooks_initialized); 249211885Spjd 250211885Spjd /* 251211885Spjd * If SIGCHLD was received, garbage collect finished processes. 252211885Spjd */ 253211885Spjd while (sigchld && (pid = wait3(&status, WNOHANG, NULL)) > 0) { 254211885Spjd mtx_lock(&hookprocs_lock); 255211885Spjd hp = hook_find(pid); 256211885Spjd if (hp == NULL) { 257211885Spjd mtx_unlock(&hookprocs_lock); 258211885Spjd pjdlog_warning("Unknown process pid=%u", pid); 259211885Spjd continue; 260211885Spjd } 261211885Spjd hook_remove(hp); 262211885Spjd mtx_unlock(&hookprocs_lock); 263211885Spjd if (WIFEXITED(status) && WEXITSTATUS(status) == 0) { 264211885Spjd pjdlog_debug(1, "Hook exited gracefully (pid=%u, cmd=[%s]).", 265211885Spjd pid, hp->hp_comm); 266211885Spjd } else if (WIFSIGNALED(status)) { 267211885Spjd pjdlog_error("Hook was killed (pid=%u, signal=%d, cmd=[%s]).", 268211885Spjd pid, WTERMSIG(status), hp->hp_comm); 269211885Spjd } else { 270211885Spjd pjdlog_error("Hook exited ungracefully (pid=%u, exitcode=%d, cmd=[%s]).", 271211885Spjd pid, WIFEXITED(status) ? WEXITSTATUS(status) : -1, 272211885Spjd hp->hp_comm); 273211885Spjd } 274211885Spjd hook_free(hp); 275211885Spjd } 276211885Spjd 277211885Spjd /* 278211885Spjd * Report about processes that are running for a long time. 279211885Spjd */ 280211885Spjd now = time(NULL); 281211885Spjd mtx_lock(&hookprocs_lock); 282211885Spjd TAILQ_FOREACH_SAFE(hp, &hookprocs, hp_next, hp2) { 283211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 284211885Spjd assert(hp->hp_pid > 0); 285211885Spjd 286211885Spjd /* 287211885Spjd * If process doesn't exists we somehow missed it. 288211885Spjd * Not much can be done expect for logging this situation. 289211885Spjd */ 290211885Spjd if (kill(hp->hp_pid, 0) == -1 && errno == ESRCH) { 291211885Spjd pjdlog_warning("Hook disappeared (pid=%u, cmd=[%s]).", 292211885Spjd hp->hp_pid, hp->hp_comm); 293211885Spjd hook_remove(hp); 294211885Spjd hook_free(hp); 295211885Spjd continue; 296211885Spjd } 297211885Spjd 298211885Spjd /* 299211885Spjd * Skip proccesses younger than 1 minute. 300211885Spjd */ 301211885Spjd if (now - hp->hp_lastreport < REPORT_INTERVAL) 302211885Spjd continue; 303211885Spjd 304211885Spjd /* 305211885Spjd * Hook is running for too long, report it. 306211885Spjd */ 307211885Spjd pjdlog_warning("Hook is running for %ju seconds (pid=%u, cmd=[%s]).", 308211885Spjd (uintmax_t)(now - hp->hp_birthtime), hp->hp_pid, 309211885Spjd hp->hp_comm); 310211885Spjd hp->hp_lastreport = now; 311211885Spjd } 312211885Spjd mtx_unlock(&hookprocs_lock); 313211885Spjd} 314211885Spjd 315211885Spjdvoid 316204076Spjdhook_exec(const char *path, ...) 317204076Spjd{ 318204076Spjd va_list ap; 319204076Spjd 320204076Spjd va_start(ap, path); 321211885Spjd hook_execv(path, ap); 322204076Spjd va_end(ap); 323204076Spjd} 324204076Spjd 325211885Spjdvoid 326204076Spjdhook_execv(const char *path, va_list ap) 327204076Spjd{ 328211885Spjd struct hookproc *hp; 329204076Spjd char *args[64]; 330204076Spjd unsigned int ii; 331211885Spjd pid_t pid; 332204076Spjd 333211885Spjd assert(hooks_initialized); 334211885Spjd 335204076Spjd if (path == NULL || path[0] == '\0') 336211885Spjd return; 337204076Spjd 338204076Spjd memset(args, 0, sizeof(args)); 339204076Spjd args[0] = basename(path); 340204076Spjd for (ii = 1; ii < sizeof(args) / sizeof(args[0]); ii++) { 341204076Spjd args[ii] = va_arg(ap, char *); 342204076Spjd if (args[ii] == NULL) 343204076Spjd break; 344204076Spjd } 345204076Spjd assert(ii < sizeof(args) / sizeof(args[0])); 346204076Spjd 347211885Spjd hp = hook_alloc(path, args); 348211885Spjd if (hp == NULL) 349211885Spjd return; 350211885Spjd 351204076Spjd pid = fork(); 352204076Spjd switch (pid) { 353204076Spjd case -1: /* Error. */ 354211885Spjd pjdlog_errno(LOG_ERR, "Unable to fork to execute %s", path); 355211885Spjd return; 356204076Spjd case 0: /* Child. */ 357204076Spjd descriptors(); 358204076Spjd execv(path, args); 359204076Spjd pjdlog_errno(LOG_ERR, "Unable to execute %s", path); 360204076Spjd exit(EX_SOFTWARE); 361204076Spjd default: /* Parent. */ 362211885Spjd hook_add(hp, pid); 363204076Spjd break; 364204076Spjd } 365204076Spjd} 366