/*
* event.c - ACPI daemon event handler
*
* Copyright (C) 2000 Andrew Henroid
* Copyright (C) 2001 Sun Microsystems (thockin@sun.com)
* Copyright (C) 2004 Tim Hockin (thockin@hockin.org)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <poll.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>
#include <ctype.h>
#include <regex.h>
#include <signal.h>
#include "acpid.h"
#include "log.h"
#include "sock.h"
#include "ud_socket.h"
#include "libc_compat.h"
#include "event.h"
/*
* What is a rule? It's polymorphic, pretty much.
*/
#define RULE_REGEX_FLAGS (REG_EXTENDED | REG_ICASE | REG_NOSUB | REG_NEWLINE)
struct rule {
enum {
RULE_NONE = 0,
RULE_CMD,
RULE_CLIENT,
} type;
char *origin;
regex_t *event;
union {
char *cmd;
int fd;
} action;
struct rule *next;
struct rule *prev;
};
struct rule_list {
struct rule *head;
struct rule *tail;
};
static struct rule_list drop_list;
static struct rule_list client_list;
static struct rule_list cmd_list;
/* rule routines */
static void enlist_rule(struct rule_list *list, struct rule *r);
static void delist_rule(struct rule_list *list, struct rule *r);
static struct rule *new_rule(void);
static void free_rule(struct rule *r);
/* other helper routines */
static void lock_rules(void);
static void unlock_rules(void);
static sigset_t *signals_handled(void);
static struct rule *parse_file(int fd_rule, const char *file);
static struct rule *parse_client(int client);
static int do_cmd_rule(struct rule *r, const char *event);
static int do_client_rule(struct rule *r, const char *event);
static int safe_write(int fd, const char *buf, int len);
static char *parse_cmd(const char *cmd, const char *event);
static int check_escapes(const char *str);
extern const char *dropaction;
/*
* read in all the configuration files
*/
int
acpid_read_conf(const char *confdir)
{
DIR *dir;
struct dirent *dirent;
int nrules = 0;
regex_t preg;
int rc = 0;
lock_rules();
dir = opendir(confdir);
if (!dir) {
acpid_log(LOG_ERR, "opendir(%s): %s",
confdir, strerror(errno));
unlock_rules();
return -1;
}
/* Compile the regular expression. This is based on run-parts(8). */
rc = regcomp(&preg, "^[a-zA-Z0-9_-]+$", RULE_REGEX_FLAGS);
if (rc) {
closedir(dir);
acpid_log(LOG_ERR, "regcomp(): %d", rc);
unlock_rules();
return -1;
}
/* scan all the files */
while ((dirent = readdir(dir))) {
struct rule *r;
struct stat stat_buf;
char *file = NULL; /* rename: filename */
int fd_rule;
/* skip "." and ".." */
if (strncmp(dirent->d_name, ".", sizeof(dirent->d_name)) == 0)
continue;
if (strncmp(dirent->d_name, "..", sizeof(dirent->d_name)) == 0)
continue;
if (asprintf(&file, "%s/%s", confdir, dirent->d_name) < 0) {
acpid_log(LOG_ERR, "asprintf: %s", strerror(errno));
regfree(&preg);
closedir(dir);
unlock_rules();
return -1;
}
/* skip any files that don't match the run-parts convention */
if (regexec(&preg, dirent->d_name, 0, NULL, 0) != 0) {
acpid_log(LOG_INFO, "skipping conf file %s", file);
free(file);
continue;
}
/* ??? Check for DT_UNKNOWN and do this, then "else if" on not DT_REG
and do the same as the !S_ISREG() branch below. */
if (dirent->d_type != DT_REG) { /* may be DT_UNKNOWN ...*/
/* allow only regular files and symlinks to files */
if (fstatat(dirfd(dir), dirent->d_name, &stat_buf, 0) != 0) {
acpid_log(LOG_ERR, "fstatat(%s): %s", file, strerror(errno));
free(file);
continue; /* keep trying the rest of the files */
}
if (!S_ISREG(stat_buf.st_mode)) {
acpid_log(LOG_INFO, "skipping non-file %s", file);
free(file);
continue; /* skip non-regular files */
}
}
/* open the rule file (might want to move this into parse_file()?) */
if ((fd_rule = openat(dirfd(dir), dirent->d_name,
O_RDONLY|O_CLOEXEC|O_NONBLOCK)) == -1) {
/* something went _really_ wrong.. Not Gonna Happen(tm) */
acpid_log(LOG_ERR, "openat(%s): %s", file, strerror(errno));
free(file);
/* ??? Too extreme? Why not just continue? */
closedir(dir);
regfree(&preg);
unlock_rules();
return -1;
}
/* fd is closed by parse_file() */
r = parse_file(fd_rule, file);
if (r) {
/* if this is a drop rule */
if (!strcmp(r->action.cmd, dropaction))
enlist_rule(&drop_list, r);
else
enlist_rule(&cmd_list, r);
nrules++;
}
free(file);
}
regfree(&preg);
closedir(dir);
unlock_rules();
acpid_log(LOG_INFO, "%d rule%s loaded", nrules, (nrules == 1)?"":"s");
return 0;
}
/*
* cleanup all rules
*/
int
acpid_cleanup_rules(int do_detach)
{
struct rule *p;
struct rule *next;
lock_rules();
if (debug_level >= 3) {
acpid_log(LOG_DEBUG, "cleaning up rules");
}
if (do_detach) {
/* tell our clients to buzz off */
p = client_list.head;
while (p) {
next = p->next;
delist_rule(&client_list, p);
close(p->action.fd);
free_rule(p);
p = next;
}
}
/* clear out our conf rules */
p = cmd_list.head;
while (p) {
next = p->next;
delist_rule(&cmd_list, p);
free_rule(p);
p = next;
}
/* drop the drop rules */
p = drop_list.head;
while (p) {
next = p->next;
delist_rule(&drop_list, p);
free_rule(p);
p = next;
}
unlock_rules();
return 0;
}
static struct rule *
parse_file(int fd_rule, const char *file)
{
FILE *fp;
char buf[512];
int line = 0;
struct rule *r;
acpid_log(LOG_DEBUG, "parsing conf file %s", file);
/* r - read-only, e - O_CLOEXEC */
fp = fdopen(fd_rule, "re");
if (!fp) {
acpid_log(LOG_ERR, "fopen(%s): %s", file, strerror(errno));
return NULL;
}
/* make a new rule */
r = new_rule();
if (!r) {
fclose(fp);
return NULL;
}
r->type = RULE_CMD;
r->origin = strdup(file);
if (!r->origin) {
acpid_log(LOG_ERR, "strdup(): %s", strerror(errno));
free_rule(r);
fclose(fp);
return NULL;
}
/* read each line */
while (!feof(fp) && !ferror(fp)) {
char *p = buf;
char key[64];
char val[512];
int n;
line++;
memset(key, 0, sizeof(key));
memset(val, 0, sizeof(val));
if (fgets(buf, sizeof(buf)-1, fp) == NULL) {
continue;
}
/* skip leading whitespace */
while (*p && isspace((int)*p)) {
p++;
}
/* blank lines and comments get ignored */
if (!*p || *p == '#') {
continue;
}
/* quick parse */
n = sscanf(p, "%63[^=\n]=%255[^\n]", key, val);
if (n != 2) {
acpid_log(LOG_WARNING, "can't parse %s at line %d",
file, line);
continue;
}
if (debug_level >= 3) {
acpid_log(LOG_DEBUG, " key=\"%s\" val=\"%s\"",
key, val);
}
/* handle the parsed line */
if (!strcasecmp(key, "event")) {
int rv;
r->event = malloc(sizeof(regex_t));
if (!r->event) {
acpid_log(LOG_ERR, "malloc(): %s",
strerror(errno));
free_rule(r);
fclose(fp);
return NULL;
}
rv = regcomp(r->event, val, RULE_REGEX_FLAGS);
if (rv) {
char rbuf[128];
regerror(rv, r->event, rbuf, sizeof(rbuf));
acpid_log(LOG_ERR, "regcomp(): %s", rbuf);
free_rule(r);
fclose(fp);
return NULL;
}
} else if (!strcasecmp(key, "action")) {
if (check_escapes(val) < 0) {
acpid_log(LOG_ERR, "can't load file %s",
file);
free_rule(r);
fclose(fp);
return NULL;
}
r->action.cmd = strdup(val);
if (!r->action.cmd) {
acpid_log(LOG_ERR, "strdup(): %s",
strerror(errno));
free_rule(r);
fclose(fp);
return NULL;
}
} else {
acpid_log(LOG_WARNING,
"unknown option '%s' in %s at line %d",
key, file, line);
continue;
}
}
if (!r->event || !r->action.cmd) {
acpid_log(LOG_INFO, "skipping incomplete file %s", file);
free_rule(r);
fclose(fp);
return NULL;
}
fclose(fp);
return r;
}
int
acpid_add_client(int clifd, const char *origin)
{
struct rule *r;
int nrules = 0;
acpid_log(LOG_NOTICE, "client connected from %s", origin);
r = parse_client(clifd);
if (r) {
r->origin = strdup(origin);
enlist_rule(&client_list, r);
nrules++;
}
acpid_log(LOG_INFO, "%d client rule%s loaded",
nrules, (nrules == 1)?"":"s");
return 0;
}
static struct rule *
parse_client(int client)
{
struct rule *r;
int rv;
/* make a new rule */
r = new_rule();
if (!r) {
return NULL;
}
r->type = RULE_CLIENT;
r->action.fd = client;
r->event = malloc(sizeof(regex_t));
if (!r->event) {
acpid_log(LOG_ERR, "malloc(): %s", strerror(errno));
free_rule(r);
return NULL;
}
rv = regcomp(r->event, ".*", RULE_REGEX_FLAGS);
if (rv) {
char buf[128];
regerror(rv, r->event, buf, sizeof(buf));
acpid_log(LOG_ERR, "regcomp(): %s", buf);
free_rule(r);
return NULL;
}
return r;
}
/*
* a few rule methods
*/
static void
enlist_rule(struct rule_list *list, struct rule *r)
{
r->next = r->prev = NULL;
if (!list->head) {
list->head = list->tail = r;
} else {
list->tail->next = r;
r->prev = list->tail;
list->tail = r;
}
}
static void
delist_rule(struct rule_list *list, struct rule *r)
{
if (r->next) {
r->next->prev = r->prev;
} else {
list->tail = r->prev;
}
if (r->prev) {
r->prev->next = r->next;
} else {
list->head = r->next;;
}
r->next = r->prev = NULL;
}
static struct rule *
new_rule(void)
{
struct rule *r;
r = malloc(sizeof(*r));
if (!r) {
acpid_log(LOG_ERR, "malloc(): %s", strerror(errno));
return NULL;
}
r->type = RULE_NONE;
r->origin = NULL;
r->event = NULL;
r->action.cmd = NULL;
r->prev = r->next = NULL;
return r;
}
/* I hope you delisted the rule before you free() it */
static void
free_rule(struct rule *r)
{
if (r->type == RULE_CMD) {
if (r->action.cmd) {
free(r->action.cmd);
}
}
if (r->origin) {
free(r->origin);
}
if (r->event) {
regfree(r->event);
free(r->event);
}
free(r);
}
static int
client_is_dead(int fd)
{
struct pollfd pfd;
int r;
/* check the fd to see if it is dead */
pfd.fd = fd;
pfd.events = POLLERR | POLLHUP;
r = poll(&pfd, 1, 0);
if (r < 0) {
acpid_log(LOG_ERR, "poll(): %s", strerror(errno));
return 0;
}
return pfd.revents;
}
void
acpid_close_dead_clients(void)
{
struct rule *p;
lock_rules();
/* scan our client list */
p = client_list.head;
while (p) {
struct rule *next = p->next;
if (client_is_dead(p->action.fd)) {
struct ucred cred;
/* closed */
acpid_log(LOG_NOTICE,
"client %s has disconnected", p->origin);
delist_rule(&client_list, p);
ud_get_peercred(p->action.fd, &cred);
if (cred.uid != 0) {
non_root_clients--;
}
close(p->action.fd);
free_rule(p);
}
p = next;
}
unlock_rules();
}
/*
* the main hook for propagating events
*/
int
acpid_handle_event(const char *event)
{
struct rule *p;
int nrules = 0;
struct rule_list *ar[] = { &drop_list, &client_list, &cmd_list, NULL };
struct rule_list **lp;
/* make an event atomic wrt known signals */
lock_rules();
/* scan each rule list for any rules that care about this event */
for (lp = ar; *lp; lp++) {
struct rule_list *l = *lp;
p = l->head;
while (p) {
/* the list can change underneath us */
struct rule *pnext = p->next;
if (!regexec(p->event, event, 0, NULL, 0)) {
/* a match! */
if (logevents) {
acpid_log(LOG_INFO,
"rule from %s matched",
p->origin);
}
nrules++;
if (p->type == RULE_CMD) {
if (do_cmd_rule(p, event) == DROP_EVENT) {
/* Abort processing if event matches drop rule */
if (logevents)
acpid_log(LOG_INFO, "event dropped");
/* Skip the remaining rules. */
while (*++lp)
;
--lp;
break;
}
} else if (p->type == RULE_CLIENT) {
do_client_rule(p, event);
} else {
acpid_log(LOG_WARNING,
"unknown rule type: %d",
p->type);
}
} else {
if (debug_level >= 3 && logevents) {
acpid_log(LOG_INFO,
"rule from %s did not match",
p->origin);
}
}
p = pnext;
}
}
unlock_rules();
if (logevents) {
acpid_log(LOG_INFO, "%d total rule%s matched",
nrules, (nrules == 1)?"":"s");
}
return 0;
}
/* helper functions to block signals while iterating */
static sigset_t *
signals_handled(void)
{
static sigset_t set;
sigemptyset(&set);
sigaddset(&set, SIGHUP);
sigaddset(&set, SIGTERM);
sigaddset(&set, SIGQUIT);
sigaddset(&set, SIGINT);
return &set;
}
static void
lock_rules(void)
{
if (debug_level >= 4) {
acpid_log(LOG_DEBUG, "blocking signals for rule lock");
}
sigprocmask(SIG_BLOCK, signals_handled(), NULL);
}
static void
unlock_rules(void)
{
if (debug_level >= 4) {
acpid_log(LOG_DEBUG, "unblocking signals for rule lock");
}
sigprocmask(SIG_UNBLOCK, signals_handled(), NULL);
}
/*
* the meat of the rules
*/
static int
do_cmd_rule(struct rule *rule, const char *event)
{
pid_t pid;
int status;
const char *action;
if (!strcmp(rule->action.cmd, dropaction))
return DROP_EVENT;
pid = fork();
switch (pid) {
case -1:
acpid_log(LOG_ERR, "fork(): %s", strerror(errno));
return -1;
case 0: /* child */
/* parse the commandline, doing any substitutions needed */
action = parse_cmd(rule->action.cmd, event);
if (logevents) {
acpid_log(LOG_INFO,
"executing action \"%s\"", action);
}
/* reset signals */
signal(SIGHUP, SIG_DFL);
signal(SIGTERM, SIG_DFL);
signal(SIGINT, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
signal(SIGPIPE, SIG_DFL);
sigprocmask(SIG_UNBLOCK, signals_handled(), NULL);
if (debug_level && logevents) {
fprintf(stdout, "BEGIN HANDLER MESSAGES\n");
}
umask(0077);
execl("/bin/sh", "/bin/sh", "-c", action, NULL);
/* should not get here */
acpid_log(LOG_ERR, "execl(): %s", strerror(errno));
_exit(EXIT_FAILURE);
}
/* parent */
waitpid(pid, &status, 0);
if (debug_level && logevents) {
fprintf(stdout, "END HANDLER MESSAGES\n");
}
if (logevents) {
if (WIFEXITED(status)) {
acpid_log(LOG_INFO, "action exited with status %d",
WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
acpid_log(LOG_INFO, "action exited on signal %d",
WTERMSIG(status));
} else {
acpid_log(LOG_INFO, "action exited with status %d",
status);
}
}
return 0;
}
static int
do_client_rule(struct rule *rule, const char *event)
{
int r;
int client = rule->action.fd;
if (logevents) {
acpid_log(LOG_INFO, "notifying client %s", rule->origin);
}
r = safe_write(client, event, strlen(event));
if (r < 0 && errno == EPIPE) {
struct ucred cred;
/* closed */
acpid_log(LOG_NOTICE,
"client %s has disconnected", rule->origin);
delist_rule(&client_list, rule);
ud_get_peercred(rule->action.fd, &cred);
if (cred.uid != 0) {
non_root_clients--;
}
close(rule->action.fd);
free_rule(rule);
return -1;
}
safe_write(client, "\n", 1);
return 0;
}
#define NTRIES 100
static int
safe_write(int fd, const char *buf, int len)
{
int r;
int ttl = 0;
int ntries = NTRIES;
do {
r = TEMP_FAILURE_RETRY (write(fd, buf+ttl, len-ttl) );
if (r < 0) {
if (errno != EAGAIN) {
/* a legit error */
return r;
}
ntries--;
} else if (r > 0) {
/* as long as we make forward progress, reset ntries */
ntries = NTRIES;
ttl += r;
}
} while (ttl < len && ntries);
if (!ntries) {
if (debug_level >= 2) {
acpid_log(LOG_ERR, "safe_write() timed out");
}
return r;
}
return ttl;
}
static char *
parse_cmd(const char *cmd, const char *event)
{
static char buf[4096];
size_t i;
const char *p;
p = cmd;
i = 0;
memset(buf, 0, sizeof(buf));
while (i < (sizeof(buf)-1)) {
if (*p == '%') {
p++;
if (*p == 'e') {
/* handle an event expansion */
size_t size = sizeof(buf) - i;
size = snprintf(buf+i, size, "%s", event);
i += size;
p++;
continue;
}
}
if (!*p) {
break;
}
buf[i++] = *p++;
}
if (debug_level >= 2) {
acpid_log(LOG_DEBUG, "expanded \"%s\" -> \"%s\"", cmd, buf);
}
return buf;
}
static int
check_escapes(const char *str)
{
const char *p;
int r = 0;
p = str;
while (*p) {
/* found an escape */
if (*p == '%') {
p++;
if (!*p) {
acpid_log(LOG_WARNING,
"invalid escape at EOL");
return -1;
} else if (*p != '%' && *p != 'e') {
acpid_log(LOG_WARNING,
"invalid escape \"%%%c\"", *p);
r = -1;
}
}
p++;
}
return r;
}