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/*
*
* Copyright (C) 2005-2006 NFG Net Facilities Group BV support@nfg.nl
* Copyright (C) 2006 Aaron Stone aaron@serendipity.cx
*
*
* pool.c Management of process pool
*
*
* TODO:
*
* general: statistics bookkeeping
*
*
*/
#include "dbmail.h"
#define THIS_MODULE "server"
static volatile Scoreboard_t *scoreboard;
static int shmid;
static int sb_lockfd;
static FILE *scoreFD;
extern volatile sig_atomic_t GeneralStopRequested;
extern ChildInfo_t childinfo;
static void state_reset(child_state_t *child);
static int set_lock(int type);
static pid_t reap_child(void);
/*
*
*
* Scoreboard
*
*
*/
void state_reset(child_state_t *s)
{
s->pid = -1;
s->ctime = time(0);
s->status = STATE_NOOP;
s->count = 0;
// FIXME: valgrind is complaining about s->user going 2 bytes past the structure.
memset(s->client, '\0', 128);
memset(s->user, '\0', 128);
}
int set_lock(int type)
{
int result, serr;
struct flock lock;
static int retry = 0;
lock.l_type = type; /* F_RDLCK, F_WRLCK, F_UNLOCK */
lock.l_start = 0;
lock.l_whence = 0;
lock.l_len = 1;
result = fcntl(sb_lockfd, F_SETLK, &lock);
if (result == -1) {
serr = errno;
switch (serr) {
case EACCES:
case EAGAIN:
case EDEADLK:
if (retry++ > 2)
TRACE(TRACE_WARNING, "Error setting lock. Still trying...");
usleep(10);
set_lock(type);
break;
default:
// ignore the rest
retry = 0;
break;
}
errno = serr;
} else {
retry = 0;
}
return result;
}
void scoreboard_new(serverConfig_t * conf)
{
int serr;
if ((shmid = shmget(IPC_PRIVATE,
(sizeof(child_state_t) * HARD_MAX_CHILDREN),
0644 | IPC_CREAT)) == -1) {
serr = errno;
TRACE(TRACE_FATAL, "shmget failed [%s]",
strerror(serr));
}
scoreboard = shmat(shmid, (void *) 0, 0);
serr=errno;
if (scoreboard == (Scoreboard_t *) (-1)) {
TRACE(TRACE_FATAL, "scoreboard init failed [%s]",
strerror(serr));
scoreboard_delete();
}
scoreboard_lock_new();
scoreboard->conf = conf;
scoreboard_setup();
scoreboard_conf_check();
/* Make sure that we clean up our shared memory segments when we exit
* normally (i.e. not by kill -9, if you do that, you get to clean this
* up yourself!)
* */
atexit(scoreboard_delete); }
char * scoreboard_lock_getfilename(void)
{
return g_strdup_printf("%s_%d.LCK", SCOREBOARD_LOCK_FILE, getpid());
}
void scoreboard_lock_new(void)
{
gchar *statefile = scoreboard_lock_getfilename();
if ( (sb_lockfd = open(statefile,O_EXCL|O_RDWR|O_CREAT|O_TRUNC,0600)) < 0) {
TRACE(TRACE_FATAL, "Could not open lockfile [%s]", statefile);
}
g_free(statefile);
}
void scoreboard_setup(void) {
int i;
scoreboard_wrlck();
for (i = 0; i < HARD_MAX_CHILDREN; i++)
state_reset((child_state_t *)&scoreboard->child[i]);
scoreboard_unlck();
}
void scoreboard_conf_check(void)
{
/* some sanity checks on boundaries */
scoreboard_wrlck();
if (scoreboard->conf->maxChildren > HARD_MAX_CHILDREN) {
TRACE(TRACE_WARNING, "MAXCHILDREN too large. Decreasing to [%d]",
HARD_MAX_CHILDREN);
scoreboard->conf->maxChildren = HARD_MAX_CHILDREN;
} else if (scoreboard->conf->maxChildren < scoreboard->conf->startChildren) {
TRACE(TRACE_WARNING, "MAXCHILDREN too small. Increasing to NCHILDREN [%d]",
scoreboard->conf->startChildren);
scoreboard->conf->maxChildren = scoreboard->conf->startChildren;
}
if (scoreboard->conf->maxSpareChildren > scoreboard->conf->maxChildren) {
TRACE(TRACE_WARNING, "MAXSPARECHILDREN too large. Decreasing to MAXCHILDREN [%d]",
scoreboard->conf->maxChildren);
scoreboard->conf->maxSpareChildren = scoreboard->conf->maxChildren;
} else if (scoreboard->conf->maxSpareChildren < scoreboard->conf->minSpareChildren) {
TRACE(TRACE_WARNING, "MAXSPARECHILDREN too small. Increasing to MINSPARECHILDREN [%d]",
scoreboard->conf->minSpareChildren);
scoreboard->conf->maxSpareChildren = scoreboard->conf->minSpareChildren;
}
scoreboard_unlck();
}
static unsigned scoreboard_cleanup(void)
{
/* return the number of children still registered as being alive */
unsigned count = 0;
int i, status = 0;
pid_t chpid = 0;
for (i = 0; i < scoreboard->conf->maxChildren; i++) {
scoreboard_rdlck();
chpid = scoreboard->child[i].pid;
status = scoreboard->child[i].status;
scoreboard_unlck();
if (chpid <= 0)
continue;
count++;
if (status == STATE_WAIT) {
if (waitpid(chpid, NULL, WNOHANG | WUNTRACED) == chpid)
scoreboard_release(chpid);
}
}
return count;
}
void scoreboard_release(pid_t pid)
{
int key;
key = getKey(pid);
if (key == -1)
return;
scoreboard_wrlck();
state_reset((child_state_t *)&scoreboard->child[key]);
scoreboard_unlck();
}
void scoreboard_delete(void)
{
gchar *statefile;
extern int isGrandChildProcess;
/* The middle process removes the scoreboards, so only bail out
* if we are a grandchild / connection handler process. */
if (isGrandChildProcess)
return;
if (shmdt((const void *)scoreboard) == -1)
TRACE(TRACE_ERROR, "detach shared mem failed");
if (shmctl(shmid, IPC_RMID, NULL) == -1)
TRACE(TRACE_ERROR, "delete shared mem segment failed");
statefile = scoreboard_lock_getfilename();
if (unlink(statefile) == -1)
TRACE(TRACE_ERROR, "error deleting scoreboard lock file [%s]",
statefile);
g_free(statefile);
return;
}
int count_spare_children(void)
{
int i, count;
count = 0;
scoreboard_rdlck();
for (i = 0; i < scoreboard->conf->maxChildren; i++) {
if (scoreboard->child[i].pid > 0
&& scoreboard->child[i].status == STATE_IDLE)
count++;
}
scoreboard_unlck();
return count;
}
int count_children(void)
{
int i, count;
count = 0;
scoreboard_rdlck();
for (i = 0; i < scoreboard->conf->maxChildren; i++) {
if (scoreboard->child[i].pid > 0)
count++;
}
scoreboard_unlck();
return count;
}
pid_t get_idle_spare(void)
{
int i;
pid_t idlepid = (pid_t) -1;
/* get the last-in-first-out idle process */
scoreboard_rdlck();
for (i = scoreboard->conf->maxChildren - 1; i >= 0; i--) {
if ((scoreboard->child[i].pid > 0) && (scoreboard->child[i].status == STATE_IDLE)) {
idlepid = scoreboard->child[i].pid;
break;
}
}
scoreboard_unlck();
return idlepid;
}
int getKey(pid_t pid)
{
int i;
scoreboard_rdlck();
for (i = 0; i < scoreboard->conf->maxChildren; i++) {
if (scoreboard->child[i].pid == pid) {
scoreboard_unlck();
return i;
}
}
scoreboard_unlck();
TRACE(TRACE_ERROR, "pid NOT found on scoreboard [%d]", pid);
return -1;
}
/*
*
*
* Child
*
*
*/
int child_register(void)
{
int i;
pid_t chpid = getpid();
TRACE(TRACE_MESSAGE, "register child [%d]", chpid);
scoreboard_rdlck();
for (i = 0; i < scoreboard->conf->maxChildren; i++) {
if (scoreboard->child[i].pid == -1)
break;
if (scoreboard->child[i].pid == chpid) {
TRACE(TRACE_ERROR, "child already registered.");
scoreboard_unlck();
return -1;
}
}
scoreboard_unlck();
if (i == scoreboard->conf->maxChildren) {
TRACE(TRACE_WARNING, "no empty slot found");
return -1;
}
scoreboard_wrlck();
scoreboard->child[i].pid = chpid;
scoreboard->child[i].status = STATE_IDLE;
scoreboard_unlck();
TRACE(TRACE_INFO, "initializing child_state [%d] using slot [%d]",
chpid, i);
return 0;
}
void child_reg_connected(void)
{
int key;
pid_t pid;
if (! scoreboard) // cli server
return;
pid = getpid();
key = getKey(pid);
if (key == -1)
TRACE(TRACE_FATAL, "unable to find this pid on the scoreboard");
scoreboard_wrlck();
scoreboard->child[key].status = STATE_CONNECTED;
scoreboard->child[key].count++;
scoreboard_unlck();
}
void child_reg_connected_client(const char *ip, const char *name)
{
int key;
pid_t pid;
if (! scoreboard) // cli server
return;
pid = getpid();
key = getKey(pid);
if (key == -1)
TRACE(TRACE_FATAL, "unable to find this pid on the scoreboard");
scoreboard_wrlck();
if (scoreboard->child[key].status == STATE_CONNECTED) {
if (name && name[0])
strncpy(scoreboard->child[key].client, name, 127);
else
strncpy(scoreboard->child[key].client, ip, 127);
} else {
TRACE(TRACE_MESSAGE, "client disconnected before status detail was logged");
}
scoreboard_unlck();
}
void child_reg_connected_user(char *user)
{
int key;
pid_t pid;
if (! scoreboard) // cli server
return;
pid = getpid();
key = getKey(pid);
if (key == -1)
TRACE(TRACE_FATAL, "unable to find this pid on the scoreboard");
scoreboard_wrlck();
if (scoreboard->child[key].status == STATE_CONNECTED) {
strncpy(scoreboard->child[key].user, user, 127);
} else {
TRACE(TRACE_MESSAGE, "client disconnected before status detail was logged");
}
scoreboard_unlck();
}
void child_reg_disconnected(void)
{
int key;
pid_t pid;
pid = getpid();
key = getKey(pid);
if (key == -1)
TRACE(TRACE_FATAL, "unable to find this pid on the scoreboard");
scoreboard_wrlck();
scoreboard->child[key].status = STATE_IDLE;
memset(scoreboard->child[key].client, '\0', 128);
memset(scoreboard->child[key].user, '\0', 128);
scoreboard_unlck();
}
void child_unregister(void)
{
/*
*
* Set the state for this slot to WAIT
* so the parent process can do a waitpid()
*
*/
int key;
pid_t pid;
if (! scoreboard) // cli server
return;
pid = getpid();
key = getKey(pid);
if (key == -1)
TRACE(TRACE_FATAL, "unable to find this pid on the scoreboard");
scoreboard_wrlck();
scoreboard->child[key].status = STATE_WAIT;
scoreboard_unlck();
}
/*
*
*
* Server
*
*
*/
/* Start the first batch of forked processes */
void manage_start_children(void)
{
int i;
for (i = 0; i < scoreboard->conf->startChildren; i++) {
if (CreateChild(&childinfo) > -1)
continue;
manage_stop_children();
TRACE(TRACE_FATAL, "could not create children.");
exit(0);
}
scoreboard_state();
}
void manage_stop_children(void)
{
/*
*
* cleanup all remaining forked processes
*
*/
int alive = 0;
int i, cnt = 0;
pid_t chpid;
TRACE(TRACE_MESSAGE, "General stop requested. Killing children...");
for (i=0; i < scoreboard->conf->maxChildren; i++) {
scoreboard_rdlck();
chpid = scoreboard->child[i].pid;
scoreboard_unlck();
if (chpid < 0)
continue;
if (kill(chpid, SIGTERM))
TRACE(TRACE_ERROR, "Cannot send SIGTERM to child [%d], error [%s]",
(int)chpid, strerror(errno));
}
alive = scoreboard_cleanup();
while (alive > 0 && cnt++ < 10) {
alive = scoreboard_cleanup();
sleep(1);
}
if (alive) {
TRACE(TRACE_INFO, "[%d] children alive after SIGTERM, sending SIGKILL",
alive);
for (i = 0; i < scoreboard->conf->maxChildren; i++) {
scoreboard_rdlck();
chpid = scoreboard->child[i].pid;
scoreboard_unlck();
if (chpid < 0)
continue;
kill(chpid, SIGKILL);;
if (waitpid(chpid, NULL, WNOHANG | WUNTRACED) == chpid)
scoreboard_release(chpid);
}
}
}
static pid_t reap_child(void)
{
pid_t chpid=0;
if ((chpid = get_idle_spare()) < 0)
return 0; // no idle children
if (kill(chpid, SIGTERM)) {
TRACE(TRACE_ERROR, "Cannot send SIGTERM to child [%d], error [%s]",
(int) chpid, strerror(errno));
return -1;
}
return 0;
}
void manage_spare_children(void)
{
/*
*
* manage spare children while running. One child more/less for each run.
*
*/
pid_t chpid = 0;
int spares, children;
int changes = 0;
int minchildren, maxchildren;
int minspares, maxspares;
if (GeneralStopRequested)
return;
// cleanup
scoreboard_cleanup();
children = count_children();
spares = count_spare_children();
/* scale up */
minchildren = scoreboard->conf->startChildren;
maxchildren = scoreboard->conf->maxChildren;
minspares = scoreboard->conf->minSpareChildren;
maxspares = scoreboard->conf->maxSpareChildren;
if ((children < minchildren || spares < minspares) && children < maxchildren) {
if ((chpid = CreateChild(&childinfo)) < 0)
return;
changes++;
}
/* scale down */
else if (children > minchildren && spares > maxspares) {
reap_child();
changes++;
}
if (changes)
scoreboard_state();
children = count_children();
}
void scoreboard_state(void)
{
char *state;
int i;
unsigned children = count_children();
unsigned spares = count_spare_children();
state = g_strdup_printf("Scoreboard state: children [%d/%d], spares [%d (%d - %d)]",
children,
scoreboard->conf->maxChildren,
spares,
scoreboard->conf->minSpareChildren,
scoreboard->conf->maxSpareChildren);
/* Log it. */
TRACE(TRACE_MESSAGE, "%s", state);
/* Top it. */
rewind(scoreFD);
int printlen, scorelen = 0; // Tally up how much data has been written out.
if ((printlen = fprintf(scoreFD, "%s\n", state)) <= 0
|| !(scorelen += printlen)) {
TRACE(TRACE_ERROR, "Couldn't write scoreboard state to top file [%s].",
strerror(errno));
}
// Fixed 78 char output width.
if ((printlen = fprintf(scoreFD, "%8s%8s%8s%8s%22s%22s\n\n",
"Child", "PID", "Status", "Count", "Client", "User") <= 0)
|| !(scorelen += printlen)) {
TRACE(TRACE_ERROR, "Couldn't write scoreboard state to top file [%s].",
strerror(errno));
}
for (i = 0; i < scoreboard->conf->maxChildren; i++) {
int chpid, status;
char *client, *user;
unsigned count;
scoreboard_rdlck();
chpid = scoreboard->child[i].pid;
status = scoreboard->child[i].status;
count = scoreboard->child[i].count;
client = scoreboard->child[i].client;
user = scoreboard->child[i].user;
scoreboard_unlck();
// Matching 78 char fixed width as above.
// Long hostnames may make the output a little messy.
if ((printlen = fprintf(scoreFD, "%8d%8d%8d%8u%22s%22s\n",
i, chpid, status, count, client, user)) <= 0
|| !(scorelen += printlen)) {
TRACE(TRACE_ERROR, "Couldn't write scoreboard state to top file [%s].",
strerror(errno));
break;
}
}
scorelen += fprintf(scoreFD, "\n");
fflush(scoreFD);
ftruncate(fileno(scoreFD), scorelen);
g_free(state);
}
static FILE *statefile_to_close;
static char *statefile_to_remove;
static void statefile_remove(void)
{
int res;
extern int isChildProcess;
if (isChildProcess)
return;
if (statefile_to_close) {
res = fclose(statefile_to_close);
if (res) TRACE(TRACE_ERROR, "Error closing statefile: [%s].",
strerror(errno));
statefile_to_close = NULL;
}
if (statefile_to_remove) {
res = unlink(statefile_to_remove);
if (res) TRACE(TRACE_ERROR, "Error unlinking statefile [%s]: [%s].",
statefile_to_remove, strerror(errno));
g_free(statefile_to_remove);
statefile_to_remove = NULL;
}
}
void statefile_create(char *scoreFile)
{
TRACE(TRACE_DEBUG, "Creating scoreboard at [%s].", scoreFile);
if (!(scoreFD = fopen(scoreFile, "w"))) {
TRACE(TRACE_ERROR, "Cannot open scorefile [%s], error was [%s]",
scoreFile, strerror(errno));
}
chmod(scoreFile, 0644);
if (scoreFD == NULL) {
TRACE(TRACE_ERROR, "Could not create scoreboard [%s].", scoreFile );
}
atexit(statefile_remove);
statefile_to_close = scoreFD;
statefile_to_remove = g_strdup(scoreFile);
}
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