hooks.c revision 213429
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 213429 2010-10-04 21:43:06Z 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 85211976Spjdstatic void hook_remove(struct hookproc *hp); 86211976Spjdstatic void hook_free(struct hookproc *hp); 87211976Spjd 88204076Spjdstatic void 89204076Spjddescriptors(void) 90204076Spjd{ 91204076Spjd long maxfd; 92204076Spjd int fd; 93204076Spjd 94204076Spjd /* 95204076Spjd * Close all descriptors. 96204076Spjd */ 97204076Spjd maxfd = sysconf(_SC_OPEN_MAX); 98204076Spjd if (maxfd < 0) { 99204076Spjd pjdlog_errno(LOG_WARNING, "sysconf(_SC_OPEN_MAX) failed"); 100204076Spjd maxfd = 1024; 101204076Spjd } 102211884Spjd for (fd = 0; fd <= maxfd; fd++) { 103211884Spjd switch (fd) { 104211884Spjd case STDIN_FILENO: 105211884Spjd case STDOUT_FILENO: 106211884Spjd case STDERR_FILENO: 107211884Spjd if (pjdlog_mode_get() == PJDLOG_MODE_STD) 108211884Spjd break; 109211884Spjd /* FALLTHROUGH */ 110211884Spjd default: 111211884Spjd close(fd); 112211884Spjd break; 113211884Spjd } 114211884Spjd } 115211884Spjd if (pjdlog_mode_get() == PJDLOG_MODE_STD) 116211884Spjd return; 117204076Spjd /* 118204076Spjd * Redirect stdin, stdout and stderr to /dev/null. 119204076Spjd */ 120204076Spjd fd = open(_PATH_DEVNULL, O_RDONLY); 121204076Spjd if (fd < 0) { 122204076Spjd pjdlog_errno(LOG_WARNING, "Unable to open %s for reading", 123204076Spjd _PATH_DEVNULL); 124204076Spjd } else if (fd != STDIN_FILENO) { 125204076Spjd if (dup2(fd, STDIN_FILENO) < 0) { 126204076Spjd pjdlog_errno(LOG_WARNING, 127204076Spjd "Unable to duplicate descriptor for stdin"); 128204076Spjd } 129204076Spjd close(fd); 130204076Spjd } 131204076Spjd fd = open(_PATH_DEVNULL, O_WRONLY); 132204076Spjd if (fd < 0) { 133204076Spjd pjdlog_errno(LOG_WARNING, "Unable to open %s for writing", 134204076Spjd _PATH_DEVNULL); 135204076Spjd } else { 136204076Spjd if (fd != STDOUT_FILENO && dup2(fd, STDOUT_FILENO) < 0) { 137204076Spjd pjdlog_errno(LOG_WARNING, 138204076Spjd "Unable to duplicate descriptor for stdout"); 139204076Spjd } 140204076Spjd if (fd != STDERR_FILENO && dup2(fd, STDERR_FILENO) < 0) { 141204076Spjd pjdlog_errno(LOG_WARNING, 142204076Spjd "Unable to duplicate descriptor for stderr"); 143204076Spjd } 144204076Spjd if (fd != STDOUT_FILENO && fd != STDERR_FILENO) 145204076Spjd close(fd); 146204076Spjd } 147204076Spjd} 148204076Spjd 149211885Spjdvoid 150211885Spjdhook_init(void) 151211885Spjd{ 152211885Spjd 153211976Spjd assert(!hooks_initialized); 154211976Spjd 155211885Spjd mtx_init(&hookprocs_lock); 156211885Spjd TAILQ_INIT(&hookprocs); 157211885Spjd hooks_initialized = true; 158211885Spjd} 159211885Spjd 160211976Spjdvoid 161211976Spjdhook_fini(void) 162211976Spjd{ 163211976Spjd struct hookproc *hp; 164211976Spjd 165211976Spjd assert(hooks_initialized); 166211976Spjd 167211976Spjd mtx_lock(&hookprocs_lock); 168211976Spjd while ((hp = TAILQ_FIRST(&hookprocs)) != NULL) { 169211976Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 170211976Spjd assert(hp->hp_pid > 0); 171211976Spjd 172211976Spjd hook_remove(hp); 173211976Spjd hook_free(hp); 174211976Spjd } 175211976Spjd mtx_unlock(&hookprocs_lock); 176211976Spjd 177211976Spjd mtx_destroy(&hookprocs_lock); 178211976Spjd TAILQ_INIT(&hookprocs); 179211976Spjd hooks_initialized = false; 180211976Spjd} 181211976Spjd 182211885Spjdstatic struct hookproc * 183211885Spjdhook_alloc(const char *path, char **args) 184211885Spjd{ 185211885Spjd struct hookproc *hp; 186211885Spjd unsigned int ii; 187211885Spjd 188211885Spjd hp = malloc(sizeof(*hp)); 189211885Spjd if (hp == NULL) { 190211885Spjd pjdlog_error("Unable to allocate %zu bytes of memory for a hook.", 191211885Spjd sizeof(*hp)); 192211885Spjd return (NULL); 193211885Spjd } 194211885Spjd 195211885Spjd hp->hp_pid = 0; 196211885Spjd hp->hp_birthtime = hp->hp_lastreport = time(NULL); 197211885Spjd (void)strlcpy(hp->hp_comm, path, sizeof(hp->hp_comm)); 198211885Spjd /* We start at 2nd argument as we don't want to have exec name twice. */ 199211885Spjd for (ii = 1; args[ii] != NULL; ii++) { 200211885Spjd (void)strlcat(hp->hp_comm, " ", sizeof(hp->hp_comm)); 201211885Spjd (void)strlcat(hp->hp_comm, args[ii], sizeof(hp->hp_comm)); 202211885Spjd } 203211885Spjd if (strlen(hp->hp_comm) >= sizeof(hp->hp_comm) - 1) { 204211885Spjd pjdlog_error("Exec path too long, correct configuration file."); 205211885Spjd free(hp); 206211885Spjd return (NULL); 207211885Spjd } 208211885Spjd hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 209211885Spjd return (hp); 210211885Spjd} 211211885Spjd 212211885Spjdstatic void 213211885Spjdhook_add(struct hookproc *hp, pid_t pid) 214211885Spjd{ 215211885Spjd 216211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 217211885Spjd assert(hp->hp_pid == 0); 218211885Spjd 219211885Spjd hp->hp_pid = pid; 220211885Spjd mtx_lock(&hookprocs_lock); 221211885Spjd hp->hp_magic = HOOKPROC_MAGIC_ONLIST; 222211885Spjd TAILQ_INSERT_TAIL(&hookprocs, hp, hp_next); 223211885Spjd mtx_unlock(&hookprocs_lock); 224211885Spjd} 225211885Spjd 226211885Spjdstatic void 227211885Spjdhook_remove(struct hookproc *hp) 228211885Spjd{ 229211885Spjd 230211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 231211885Spjd assert(hp->hp_pid > 0); 232211885Spjd assert(mtx_owned(&hookprocs_lock)); 233211885Spjd 234211885Spjd TAILQ_REMOVE(&hookprocs, hp, hp_next); 235211885Spjd hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 236211885Spjd} 237211885Spjd 238211885Spjdstatic void 239211885Spjdhook_free(struct hookproc *hp) 240211885Spjd{ 241211885Spjd 242211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 243211885Spjd assert(hp->hp_pid > 0); 244211885Spjd 245211885Spjd hp->hp_magic = 0; 246211885Spjd free(hp); 247211885Spjd} 248211885Spjd 249211885Spjdstatic struct hookproc * 250211885Spjdhook_find(pid_t pid) 251211885Spjd{ 252211885Spjd struct hookproc *hp; 253211885Spjd 254211885Spjd assert(mtx_owned(&hookprocs_lock)); 255211885Spjd 256211885Spjd TAILQ_FOREACH(hp, &hookprocs, hp_next) { 257211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 258211885Spjd assert(hp->hp_pid > 0); 259211885Spjd 260211885Spjd if (hp->hp_pid == pid) 261211885Spjd break; 262211885Spjd } 263211885Spjd 264211885Spjd return (hp); 265211885Spjd} 266211885Spjd 267211885Spjdvoid 268211976Spjdhook_check_one(pid_t pid, int status) 269211976Spjd{ 270211976Spjd struct hookproc *hp; 271211976Spjd 272211976Spjd mtx_lock(&hookprocs_lock); 273211976Spjd hp = hook_find(pid); 274211976Spjd if (hp == NULL) { 275211976Spjd mtx_unlock(&hookprocs_lock); 276211976Spjd pjdlog_debug(1, "Unknown process pid=%u", pid); 277211976Spjd return; 278211976Spjd } 279211976Spjd hook_remove(hp); 280211976Spjd mtx_unlock(&hookprocs_lock); 281211976Spjd if (WIFEXITED(status) && WEXITSTATUS(status) == 0) { 282211976Spjd pjdlog_debug(1, "Hook exited gracefully (pid=%u, cmd=[%s]).", 283211976Spjd pid, hp->hp_comm); 284211976Spjd } else if (WIFSIGNALED(status)) { 285211976Spjd pjdlog_error("Hook was killed (pid=%u, signal=%d, cmd=[%s]).", 286211976Spjd pid, WTERMSIG(status), hp->hp_comm); 287211976Spjd } else { 288211976Spjd pjdlog_error("Hook exited ungracefully (pid=%u, exitcode=%d, cmd=[%s]).", 289211976Spjd pid, WIFEXITED(status) ? WEXITSTATUS(status) : -1, 290211976Spjd hp->hp_comm); 291211976Spjd } 292211976Spjd hook_free(hp); 293211976Spjd} 294211976Spjd 295211976Spjdvoid 296213429Spjdhook_check(void) 297211885Spjd{ 298211885Spjd struct hookproc *hp, *hp2; 299211885Spjd time_t now; 300211885Spjd 301211885Spjd assert(hooks_initialized); 302211885Spjd 303211885Spjd /* 304211885Spjd * Report about processes that are running for a long time. 305211885Spjd */ 306211885Spjd now = time(NULL); 307211885Spjd mtx_lock(&hookprocs_lock); 308211885Spjd TAILQ_FOREACH_SAFE(hp, &hookprocs, hp_next, hp2) { 309211885Spjd assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 310211885Spjd assert(hp->hp_pid > 0); 311211885Spjd 312211885Spjd /* 313211885Spjd * If process doesn't exists we somehow missed it. 314211885Spjd * Not much can be done expect for logging this situation. 315211885Spjd */ 316211885Spjd if (kill(hp->hp_pid, 0) == -1 && errno == ESRCH) { 317211885Spjd pjdlog_warning("Hook disappeared (pid=%u, cmd=[%s]).", 318211885Spjd hp->hp_pid, hp->hp_comm); 319211885Spjd hook_remove(hp); 320211885Spjd hook_free(hp); 321211885Spjd continue; 322211885Spjd } 323211885Spjd 324211885Spjd /* 325211885Spjd * Skip proccesses younger than 1 minute. 326211885Spjd */ 327211885Spjd if (now - hp->hp_lastreport < REPORT_INTERVAL) 328211885Spjd continue; 329211885Spjd 330211885Spjd /* 331211885Spjd * Hook is running for too long, report it. 332211885Spjd */ 333211885Spjd pjdlog_warning("Hook is running for %ju seconds (pid=%u, cmd=[%s]).", 334211885Spjd (uintmax_t)(now - hp->hp_birthtime), hp->hp_pid, 335211885Spjd hp->hp_comm); 336211885Spjd hp->hp_lastreport = now; 337211885Spjd } 338211885Spjd mtx_unlock(&hookprocs_lock); 339211885Spjd} 340211885Spjd 341211885Spjdvoid 342204076Spjdhook_exec(const char *path, ...) 343204076Spjd{ 344204076Spjd va_list ap; 345204076Spjd 346204076Spjd va_start(ap, path); 347211885Spjd hook_execv(path, ap); 348204076Spjd va_end(ap); 349204076Spjd} 350204076Spjd 351211885Spjdvoid 352204076Spjdhook_execv(const char *path, va_list ap) 353204076Spjd{ 354211885Spjd struct hookproc *hp; 355204076Spjd char *args[64]; 356204076Spjd unsigned int ii; 357211885Spjd pid_t pid; 358204076Spjd 359211885Spjd assert(hooks_initialized); 360211885Spjd 361204076Spjd if (path == NULL || path[0] == '\0') 362211885Spjd return; 363204076Spjd 364204076Spjd memset(args, 0, sizeof(args)); 365204076Spjd args[0] = basename(path); 366204076Spjd for (ii = 1; ii < sizeof(args) / sizeof(args[0]); ii++) { 367204076Spjd args[ii] = va_arg(ap, char *); 368204076Spjd if (args[ii] == NULL) 369204076Spjd break; 370204076Spjd } 371204076Spjd assert(ii < sizeof(args) / sizeof(args[0])); 372204076Spjd 373211885Spjd hp = hook_alloc(path, args); 374211885Spjd if (hp == NULL) 375211885Spjd return; 376211885Spjd 377204076Spjd pid = fork(); 378204076Spjd switch (pid) { 379204076Spjd case -1: /* Error. */ 380211885Spjd pjdlog_errno(LOG_ERR, "Unable to fork to execute %s", path); 381213183Spjd hook_free(hp); 382211885Spjd return; 383204076Spjd case 0: /* Child. */ 384204076Spjd descriptors(); 385204076Spjd execv(path, args); 386204076Spjd pjdlog_errno(LOG_ERR, "Unable to execute %s", path); 387204076Spjd exit(EX_SOFTWARE); 388204076Spjd default: /* Parent. */ 389211885Spjd hook_add(hp, pid); 390204076Spjd break; 391204076Spjd } 392204076Spjd} 393