mirror of
https://github.com/samba-team/samba.git
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503 lines
9.5 KiB
C
503 lines
9.5 KiB
C
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/*
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Unix SMB/CIFS implementation.
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Common server globals
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Copyright (C) Simo Sorce <idra@samba.org> 2011
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "includes.h"
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#include "system/time.h"
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#include "system/shmem.h"
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#include "system/filesys.h"
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#include "server_prefork.h"
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#include "../lib/util/util.h"
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struct prefork_pool {
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int listen_fd;
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int lock_fd;
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prefork_main_fn_t *main_fn;
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void *private_data;
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int pool_size;
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struct pf_worker_data *pool;
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};
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int prefork_pool_destructor(struct prefork_pool *pfp)
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{
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munmap(pfp->pool, pfp->pool_size * sizeof(struct pf_worker_data));
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return 0;
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}
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bool prefork_create_pool(struct tevent_context *ev_ctx,
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TALLOC_CTX *mem_ctx, int listen_fd,
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int min_children, int max_children,
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prefork_main_fn_t *main_fn, void *private_data,
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struct prefork_pool **pf_pool)
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{
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struct prefork_pool *pfp;
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pid_t pid;
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time_t now = time(NULL);
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size_t data_size;
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int ret;
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int i;
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pfp = talloc(mem_ctx, struct prefork_pool);
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if (!pfp) {
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DEBUG(1, ("Out of memory!\n"));
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return false;
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}
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pfp->listen_fd = listen_fd;
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pfp->main_fn = main_fn;
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pfp->private_data = private_data;
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pfp->lock_fd = create_unlink_tmp(NULL);
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if (pfp->lock_fd == -1) {
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DEBUG(1, ("Failed to create prefork lock fd!\n"));
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talloc_free(pfp);
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return false;
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}
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pfp->pool_size = max_children;
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data_size = sizeof(struct pf_worker_data) * max_children;
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pfp->pool = mmap(NULL, data_size, PROT_READ|PROT_WRITE,
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MAP_SHARED|MAP_ANONYMOUS, -1, 0);
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if (pfp->pool == MAP_FAILED) {
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DEBUG(1, ("Failed to mmap memory for prefork pool!\n"));
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talloc_free(pfp);
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return false;
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}
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talloc_set_destructor(pfp, prefork_pool_destructor);
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for (i = 0; i < min_children; i++) {
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pid = sys_fork();
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switch (pid) {
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case -1:
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DEBUG(1, ("Failed to prefork child n. %d !\n", i));
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break;
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case 0: /* THE CHILD */
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pfp->pool[i].status = PF_WORKER_IDLE;
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ret = pfp->main_fn(ev_ctx, &pfp->pool[i],
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pfp->listen_fd, pfp->lock_fd,
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pfp->private_data);
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exit(ret);
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default: /* THE PARENT */
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pfp->pool[i].pid = pid;
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pfp->pool[i].started = now;
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break;
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}
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}
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*pf_pool = pfp;
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return true;
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}
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int prefork_add_children(struct tevent_context *ev_ctx,
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struct prefork_pool *pfp,
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int num_children)
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{
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pid_t pid;
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time_t now = time(NULL);
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int ret;
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int i, j;
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for (i = 0, j = 0; i < pfp->pool_size && j < num_children; i++) {
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if (pfp->pool[i].status != PF_WORKER_NONE) {
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continue;
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}
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pid = sys_fork();
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switch (pid) {
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case -1:
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DEBUG(1, ("Failed to prefork child n. %d !\n", j));
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break;
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case 0: /* THE CHILD */
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pfp->pool[i].status = PF_WORKER_IDLE;
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ret = pfp->main_fn(ev_ctx, &pfp->pool[i],
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pfp->listen_fd, pfp->lock_fd,
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pfp->private_data);
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pfp->pool[i].status = PF_WORKER_EXITING;
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exit(ret);
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default: /* THE PARENT */
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pfp->pool[i].pid = pid;
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pfp->pool[i].started = now;
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j++;
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break;
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}
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}
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DEBUG(5, ("Added %d children!\n", j));
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return j;
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}
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struct prefork_oldest {
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int num;
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time_t started;
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};
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/* sort in inverse order */
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static int prefork_sort_oldest(const void *ap, const void *bp)
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{
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struct prefork_oldest *a = (struct prefork_oldest *)ap;
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struct prefork_oldest *b = (struct prefork_oldest *)bp;
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if (a->started == b->started) {
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return 0;
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}
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if (a->started < b->started) {
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return 1;
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}
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return -1;
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}
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int prefork_retire_children(struct prefork_pool *pfp,
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int num_children, time_t age_limit)
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{
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time_t now = time(NULL);
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struct prefork_oldest *oldest;
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int i, j;
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oldest = talloc_array(pfp, struct prefork_oldest, pfp->pool_size);
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if (!oldest) {
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return -1;
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}
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for (i = 0; i < pfp->pool_size; i++) {
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oldest[i].num = i;
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if (pfp->pool[i].status == PF_WORKER_IDLE) {
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oldest[i].started = pfp->pool[i].started;
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} else {
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oldest[i].started = now;
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}
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}
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qsort(oldest, pfp->pool_size,
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sizeof(struct prefork_oldest),
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prefork_sort_oldest);
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for (i = 0, j = 0; i < pfp->pool_size && j < num_children; i++) {
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if (pfp->pool[i].status == PF_WORKER_IDLE &&
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pfp->pool[i].started <= age_limit) {
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/* tell the child it's time to give up */
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DEBUG(5, ("Retiring pid %d!\n", pfp->pool[i].pid));
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pfp->pool[i].cmds = PF_SRV_MSG_EXIT;
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kill(pfp->pool[i].pid, SIGHUP);
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j++;
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}
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}
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return j;
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}
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int prefork_count_active_children(struct prefork_pool *pfp, int *total)
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{
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int i, a, t;
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a = 0;
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t = 0;
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for (i = 0; i < pfp->pool_size; i++) {
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if (pfp->pool[i].status == PF_WORKER_NONE) {
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continue;
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}
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t++;
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if (pfp->pool[i].num_clients == 0) {
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continue;
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}
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a++;
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}
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*total = t;
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return a;
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}
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/* to be used to finally mark a children as dead, so that it's slot can
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* be reused */
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bool prefork_mark_pid_dead(struct prefork_pool *pfp, pid_t pid)
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{
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int i;
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for (i = 0; i < pfp->pool_size; i++) {
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if (pfp->pool[i].pid == pid) {
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if (pfp->pool[i].status != PF_WORKER_EXITING) {
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DEBUG(2, ("pid %d terminated abnormally!\n",
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(int)pid));
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}
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/* reset all fields,
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* this makes status = PF_WORK_NONE */
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memset(&pfp->pool[i], 0,
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sizeof(struct pf_worker_data));
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return true;
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}
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}
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return false;
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}
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/* ==== Functions used by children ==== */
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static SIG_ATOMIC_T pf_alarm;
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static void pf_alarm_cb(int signum)
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{
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pf_alarm = 1;
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}
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/*
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* Parameters:
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* pf - the worker shared data structure
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* lock_fd - the file descriptor used for locking
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* timeout - expressed in seconds:
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* -1 never timeouts,
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* 0 timeouts immediately
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* N seconds before timing out
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*
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* Returns values:
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* negative errno on fatal error
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* 0 on success to acquire lock
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* -1 on timeout/lock held by other
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* -2 on server msg to terminate
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* ERRNO on other errors
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*/
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static int prefork_grab_lock(struct pf_worker_data *pf,
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int lock_fd, int timeout)
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{
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struct flock lock;
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int op;
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int ret;
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if (pf->cmds == PF_SRV_MSG_EXIT) {
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return -2;
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}
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pf_alarm = 0;
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if (timeout > 0) {
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CatchSignal(SIGALRM, pf_alarm_cb);
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alarm(timeout);
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}
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if (timeout == 0) {
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op = F_SETLK;
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} else {
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op = F_SETLKW;
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}
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ret = 0;
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do {
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ZERO_STRUCT(lock);
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lock.l_type = F_WRLCK;
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lock.l_whence = SEEK_SET;
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ret = fcntl(lock_fd, op, &lock);
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if (ret == 0) break;
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ret = errno;
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if (pf->cmds == PF_SRV_MSG_EXIT) {
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ret = -2;
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goto done;
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}
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switch (ret) {
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case EINTR:
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break;
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case EACCES:
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case EAGAIN:
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/* lock held by other proc */
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ret = -1;
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goto done;
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default:
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goto done;
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}
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if (pf_alarm == 1) {
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/* timed out */
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ret = -1;
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goto done;
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}
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} while (timeout != 0);
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if (ret != 0) {
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/* We have the Lock */
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pf->status = PF_WORKER_ACCEPTING;
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}
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done:
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if (timeout > 0) {
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alarm(0);
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CatchSignal(SIGALRM, SIG_IGN);
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}
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if (ret > 0) {
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DEBUG(1, ("Failed to get lock (%d, %s)!\n",
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ret, strerror(ret)));
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}
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return ret;
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}
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/*
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* Parameters:
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* pf - the worker shared data structure
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* lock_fd - the file descriptor used for locking
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* timeout - expressed in seconds:
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* -1 never timeouts,
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* 0 timeouts immediately
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* N seconds before timing out
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*
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* Returns values:
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* negative errno on fatal error
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* 0 on success to release lock
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* -1 on timeout
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* ERRNO on error
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*/
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static int prefork_release_lock(struct pf_worker_data *pf,
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int lock_fd, int timeout)
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{
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struct flock lock;
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int op;
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int ret;
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pf_alarm = 0;
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if (timeout > 0) {
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CatchSignal(SIGALRM, pf_alarm_cb);
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alarm(timeout);
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}
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if (timeout == 0) {
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op = F_SETLK;
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} else {
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op = F_SETLKW;
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}
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do {
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ZERO_STRUCT(lock);
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lock.l_type = F_UNLCK;
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lock.l_whence = SEEK_SET;
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ret = fcntl(lock_fd, op, &lock);
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if (ret == 0) break;
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ret = errno;
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if (ret != EINTR) {
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goto done;
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}
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if (pf_alarm == 1) {
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/* timed out */
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ret = -1;
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goto done;
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}
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} while (timeout != 0);
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done:
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if (timeout > 0) {
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alarm(0);
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CatchSignal(SIGALRM, SIG_IGN);
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}
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if (ret > 0) {
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DEBUG(1, ("Failed to release lock (%d, %s)!\n",
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ret, strerror(ret)));
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}
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return ret;
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}
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/* returns:
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* negative errno on error
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* -2 if server commands to terminate
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* 0 if all ok
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* ERRNO on other errors
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*/
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int prefork_wait_for_client(struct pf_worker_data *pf,
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int lock_fd, int listen_fd,
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struct sockaddr *addr,
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socklen_t *addrlen, int *fd)
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{
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int ret;
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int sd = -1;
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int err;
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ret = prefork_grab_lock(pf, lock_fd, -1);
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if (ret != 0) {
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return ret;
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}
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err = 0;
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do {
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sd = accept(listen_fd, addr, addrlen);
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if (sd != -1) break;
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if (errno == EINTR) {
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if (pf->cmds == PF_SRV_MSG_EXIT) {
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err = -2;
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}
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} else {
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err = errno;
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}
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} while ((sd == -1) && (err == 0));
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/* return lock now, even if the accept failed.
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* if it takes more than 10 seconds we are in deep trouble */
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ret = prefork_release_lock(pf, lock_fd, 2);
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if (ret != 0) {
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/* we were unable to release the lock!! */
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||
|
DEBUG(0, ("Terminating due to fatal failure!\n"));
|
||
|
|
||
|
/* Just exit we cannot hold the whole server, better to error
|
||
|
* on this one client and hope it was a transiet problem */
|
||
|
err = -2;
|
||
|
}
|
||
|
|
||
|
if (err != 0) {
|
||
|
if (sd != -1) {
|
||
|
close(sd);
|
||
|
sd = -1;
|
||
|
}
|
||
|
return err;
|
||
|
}
|
||
|
|
||
|
pf->status = PF_WORKER_BUSY;
|
||
|
pf->num_clients++;
|
||
|
*fd = sd;
|
||
|
return 0;
|
||
|
}
|