8158 Want named threads API

[unleashed.git] / usr / src / cmd / ldapcachemgr / cachemgr_change.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright 2018 Joyent, Inc.
 */

#include <strings.h>
#include <stdlib.h>
#include <syslog.h>
#include <errno.h>
#include <libintl.h>
#include <door.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <procfs.h>
#include <pthread.h>
#include "cachemgr.h"

extern admin_t  current_admin;

#define CLEANUP_WAIT_TIME 60

typedef enum cleanup_type {
        CLEANUP_ALL     = 1,
        CLEANUP_BY_PID  = 2
} cleanup_type_t;

typedef struct cleanup_op {
        pid_t           pid;
        cleanup_type_t  type;
} cleanup_op_t;

typedef struct main_nscd_struct {
        pid_t           pid;                    /* main nscd pid */
        thread_t        tid;                    /* main nscd tid */
        int             in_progress;            /* A main nscd thread is */
                                                /* waiting for change or */
                                                /* copying data */
        int             is_waiting_cleanup;     /* A main nscd thread is */
                                                /* waiting for another main */
                                                /* nscd thread to be cleaned */
                                                /* up */
} main_nscd_t;

static chg_info_t chg = { DEFAULTMUTEX, DEFAULTCV, 0, NULL, NULL, NULL, 0 };

static main_nscd_t chg_main_nscd = {0, 0, 0, 0};
static mutex_t chg_main_nscd_lock = DEFAULTMUTEX;
static cond_t chg_main_nscd_cv = DEFAULTCV;

/*
 * The cookie of the configuration and its mutex
 */
static ldap_get_chg_cookie_t config_cookie = {0, 0};
static mutex_t config_cookie_lock = DEFAULTMUTEX;

static void cleanup_thread_by_pid(pid_t pid);

ldap_get_chg_cookie_t
chg_config_cookie_get(void)
{
        ldap_get_chg_cookie_t cookie;
        (void) mutex_lock(&config_cookie_lock);
        cookie = config_cookie;
        (void) mutex_unlock(&config_cookie_lock);
        return (cookie);
}

static void
chg_config_cookie_increment_seq_num(void)
{
        (void) mutex_lock(&config_cookie_lock);
        config_cookie.seq_num++;
        (void) mutex_unlock(&config_cookie_lock);
}

void
chg_config_cookie_set(ldap_get_chg_cookie_t *cookie)
{
        (void) mutex_lock(&config_cookie_lock);
        config_cookie.mgr_pid = cookie->mgr_pid;
        config_cookie.seq_num = cookie->seq_num;
        (void) mutex_unlock(&config_cookie_lock);
}
static boolean_t
chg_cookie_equal(ldap_get_chg_cookie_t *c1, ldap_get_chg_cookie_t *c2)
{
        if (c1->mgr_pid == c2->mgr_pid && c1->seq_num == c2->seq_num)
                return (B_TRUE);
        else
                return (B_FALSE);
}
/*
 * Create a node in the list and output the node. The caller can NOT free it.
 */
static  int
waiting_list_add(chg_info_t *info, pid_t pid, thread_t tid,
    waiting_list_t **wlp)
{

        waiting_list_t  *wl;

        *wlp = NULL;

        if ((wl = (waiting_list_t *)calloc(1, sizeof (waiting_list_t)))
            == NULL) {
                logit("waiting_list_add: No memory. pid %ld tid %d\n",
                    pid, tid);
                return (CHG_NO_MEMORY);
        }

        wl->pid = pid;
        wl->tid = tid;

        if (info->chg_w_first == NULL) {
                info->chg_w_first = wl;
                info->chg_w_last = wl;
        } else {
                info->chg_w_last->next = wl;
                wl->prev = info->chg_w_last;
                info->chg_w_last = wl;
        }
        *wlp = wl;
        return (CHG_SUCCESS);
}

/*
 * Find a node with matching tid in the list and remove it from the list.
 */
static int
waiting_list_delete(chg_info_t *info, thread_t tid)
{
        waiting_list_t  *wl;

        for (wl = info->chg_w_first; wl != NULL; wl = wl->next) {
                if (wl->tid == tid) {
                        if (wl->next == NULL) {
                                if (wl->prev == NULL) {
                                        info->chg_w_first = NULL;
                                        info->chg_w_last = NULL;
                                } else {
                                        wl->prev->next = NULL;
                                        info->chg_w_last =  wl->prev;
                                }
                        } else {
                                if (wl->prev == NULL) {
                                        wl->next->prev = NULL;
                                        info->chg_w_first = wl->next;
                                } else {
                                        wl->prev->next = wl->next;
                                        wl->next->prev = wl->prev;
                                }
                        }
                        free(wl);
                        return (CHG_SUCCESS);
                }
        }
        return (CHG_NOT_FOUND_IN_WAITING_LIST);
}

/*
 * Delete the thread from the waiting list and remove data when the list
 * is empty.
 */
static void
waiting_list_cleanup(chg_info_t *chg, thread_t tid)
{
        int     rc;

        rc = waiting_list_delete(chg, tid);

        if (rc == CHG_SUCCESS && chg->chg_w_first == NULL) {
                free(chg->chg_data);
                chg->chg_data = NULL;
                chg->chg_wakeup = 0;
        }
}

/*
 * Set flag by pid so it can be cleaned up.
 */
static void
waiting_list_set_cleanup(chg_info_t *info, pid_t pid)
{
        waiting_list_t  *wl;

        for (wl = info->chg_w_first; wl != NULL; wl = wl->next) {
                if (wl->pid == pid) {
                        wl->cleanup = 1;
                        break;
                }
        }
}

/*
 * Return: 1 - door client is dead, 0 - door client is alive
 */
static int
door_client_dead(void)
{
        ucred_t *uc = NULL;
        int     rc;

        if (door_ucred(&uc) == -1 && errno == EINVAL) {
                rc = 1;
        } else {
                rc = 0;
        }
        if (uc)
                ucred_free(uc);

        return (rc);
}

/*
 * This function handles GETSTATUSCHANGE call from main nscd.
 * The call can be a START op or STOP op. A cookie is sent from main nscd too.
 * The static global variable main_nscd keeps record of pid, tid and some flags.
 * If the thread is door_return(), main_nscd.pid, main_nscd.tid are set to 0.
 * When the call is START op, it checks if main_nscd.pid is 0. If it is, it
 * proceeds to wait for the change notification. If it's not, which means
 * another main nscd handling thread is still around. It sends broadcast to
 * clean up that thread and wait until the cleanup is done then proceeds to
 * wait for the change notification. If same main nscd sends START op
 * repeatedly, it'll be rejected.
 * It also checks the cookie from main nscd. If it's not the same as
 * ldap_cachemgr's cookie, door returns config change.
 * If the door call is STOP op, it creates a thread to clean up main nscd START
 * thread so it won't be blocking.
 * In waiting for the change notification phase, the thread is waken up by
 * the notification threads or by the cleanup threads.
 * If it's a notification, it copies data to the stack then door return.
 * If it's a cleanup, door_client_dead() is called to verify it then
 * door return.
 */
int
chg_get_statusChange(LineBuf *info, ldap_call_t *in, pid_t nscd_pid)
{
        int     rc = CHG_SUCCESS, another_main_nscd_thread_alive = 0;
        int     len, return_now;
        thread_t this_tid = thr_self();
        waiting_list_t  *wl = NULL;
        ldap_get_change_out_t *cout;
        ldap_get_chg_cookie_t cookie;

        info->str = NULL;
        info->len = 0;

        if (in->ldap_u.get_change.op == NS_STATUS_CHANGE_OP_START) {

                (void) mutex_lock(&chg_main_nscd_lock);
                if (chg_main_nscd.pid != 0) {
                        if (nscd_pid != chg_main_nscd.pid) {
                                /*
                                 * This is the case that nscd doesn't shut down
                                 * properly(e.g. core) and STOP op is not sent,
                                 * the thread handling it is still around and
                                 * not cleaned up yet.
                                 * Test if the thread is still alive.
                                 * If it is, clean it up.
                                 * For thr_kill, if sig is 0, a validity check
                                 * is done for the existence of the target
                                 * thread; no signal is sent.
                                 */
                                if (thr_kill(chg_main_nscd.tid, 0) == 0) {
                                        another_main_nscd_thread_alive = 1;
                                        cleanup_thread_by_pid(
                                            chg_main_nscd.pid);
                                }
                        } else if (chg_main_nscd.in_progress ||
                            chg_main_nscd.is_waiting_cleanup) {
                                /*
                                 * Same nscd pid can only send door call
                                 * one at a time and wait for ldap_cachemgr to
                                 * return change data. If it's the same pid
                                 * again, it's an nscd error.
                                 */
                                (void) mutex_unlock(&chg_main_nscd_lock);
                                return (CHG_NSCD_REPEATED_CALL);
                        }
                }
                /*
                 * Wait for another thread to be cleaned up if it's alive.
                 * After that this cond var is waken up.
                 */
                if (another_main_nscd_thread_alive) {
                        while (chg_main_nscd.in_progress) {
                                chg_main_nscd.is_waiting_cleanup = 1;
                                (void) cond_wait(&chg_main_nscd_cv,
                                    &chg_main_nscd_lock);
                        }
                }

                /*
                 * Replace pid and tid and set the flag.
                 */
                chg_main_nscd.is_waiting_cleanup = 0;
                chg_main_nscd.pid = nscd_pid;
                chg_main_nscd.tid = this_tid;
                chg_main_nscd.in_progress = 1;
                (void) mutex_unlock(&chg_main_nscd_lock);

                cookie = chg_config_cookie_get();

                if (!chg_cookie_equal(&cookie, &in->ldap_u.get_change.cookie)) {
                        /*
                         * different cookie, set new cookie and
                         * return door call right away
                         */
                        len = sizeof (ldap_get_change_out_t);
                        if ((cout = calloc(1, len)) == NULL) {
                                rc = CHG_NO_MEMORY;
                        } else {
                                cout->type = NS_STATUS_CHANGE_TYPE_CONFIG;
                                cout->cookie = cookie;
                                info->str = (char *)cout;
                                info->len = len;
                        }

                } else {
                        (void) mutex_lock(&chg.chg_lock);

                        /* wait for the change notification */
                        rc = waiting_list_add(&chg, nscd_pid, this_tid, &wl);
                        if (rc == CHG_SUCCESS) {
                                return_now = 0;
                                while (!chg.chg_wakeup) {
                                        if (wl->cleanup ||
                                            door_client_dead()) {
                                                return_now = 1;
                                                break;
                                        }
                                        (void) cond_wait(&chg.chg_cv,
                                            &chg.chg_lock);
                                }
                                /* Check if door client is still alive again */
                                if (!return_now && !wl->cleanup &&
                                    !door_client_dead()) {
                                        /* copy data to buffer */
                                        if ((info->str = malloc(
                                            chg.chg_data_size)) == NULL) {
                                                rc = CHG_NO_MEMORY;
                                        } else {
                                                (void) memcpy(info->str,
                                                    chg.chg_data,
                                                    chg.chg_data_size);
                                                info->len = chg.chg_data_size;
                                        }
                                }
                                waiting_list_cleanup(&chg, this_tid);
                        }
                        (void) mutex_unlock(&chg.chg_lock);
                }


                /*
                 * Reset pid, tid and flag, send wakeup signal.
                 */
                (void) mutex_lock(&chg_main_nscd_lock);
                chg_main_nscd.pid = 0;
                chg_main_nscd.tid = 0;
                chg_main_nscd.in_progress = 0;
                if (chg_main_nscd.is_waiting_cleanup)
                        (void) cond_broadcast(&chg_main_nscd_cv);

                (void) mutex_unlock(&chg_main_nscd_lock);

        } else if (in->ldap_u.get_change.op == NS_STATUS_CHANGE_OP_STOP) {

                cleanup_thread_by_pid(nscd_pid);
                rc = CHG_SUCCESS;

        } else {
                rc = CHG_INVALID_PARAM;
        }
        if (rc == CHG_EXCEED_MAX_THREADS)
                cleanup_thread_by_pid(0);

        return (rc);
}

/*
 * This function copies the header and data stream to the buffer
 * then send broadcast to wake up the chg_get_statusChange() threads.
 */
int
chg_notify_statusChange(char *str)
{
        ldap_get_change_out_t *cout = (ldap_get_change_out_t *)str;

        cout->cookie = chg_config_cookie_get();

        (void) mutex_lock(&chg.chg_lock);
        if (chg.chg_w_first != NULL && chg.chg_wakeup == 0) {

                if (chg.chg_data) {
                        free(chg.chg_data);
                        chg.chg_data = NULL;
                }

                chg.chg_data = str;

                if (cout->type == NS_STATUS_CHANGE_TYPE_CONFIG)
                        chg.chg_data_size = sizeof (ldap_get_change_out_t);
                else
                        /* NS_STATUS_CHANGE_TYPE_SERVER */
                        chg.chg_data_size = sizeof (ldap_get_change_out_t) -
                            sizeof (int) + cout->data_size;

                chg.chg_wakeup = 1;
                (void) cond_broadcast(&chg.chg_cv);
        }
        (void) mutex_unlock(&chg.chg_lock);

        return (CHG_SUCCESS);
}

/*
 * This is called when the configuration is refreshed.
 * The new configuration is different from the current one, a notification
 * is sent tochg_get_statusChange() threads.
 */
void
chg_test_config_change(ns_config_t *new, int *change_status)
{
        int     changed = 0;
        LineBuf new_cfg, cur_cfg;
        ns_ldap_error_t *errp = NULL;
        ldap_config_out_t *new_out, *cur_out;
        ldap_get_change_out_t   *cout;

        (void) memset(&new_cfg, 0, sizeof (LineBuf));
        (void) memset(&cur_cfg, 0, sizeof (LineBuf));
        /*
         * Flatten the config data of the newly downloaded config and
         * current default config and compare both.
         */
        if ((errp = __ns_ldap_LoadDoorInfo(&new_cfg, NULL, new, 0)) != NULL) {
                __ns_ldap_freeError(&errp);
                /* error, assume the config is changed */
                changed = 1;
        } else if ((errp = __ns_ldap_LoadDoorInfo(&cur_cfg, NULL, NULL, 0))
            != NULL) {
                __ns_ldap_freeError(&errp);
                /* error, assume the config is changed */
                changed = 1;
        }
        if (changed == 0) {
                new_out = (ldap_config_out_t *)new_cfg.str;
                cur_out = (ldap_config_out_t *)cur_cfg.str;
                if (strcmp(new_out->config_str, cur_out->config_str) != 0) {
                        changed = 1;
                        if (current_admin.debug_level >= DBG_PROFILE_REFRESH) {
                                logit("config changed.\n");
                        }
                }
        }
        if (cur_cfg.str)
                free(cur_cfg.str);
        if (new_cfg.str)
                free(new_cfg.str);

        if (changed) {

                if ((cout = calloc(1, sizeof (ldap_get_change_out_t)))
                    == NULL) {
                        logit("chg_test_config_change: No Memory\n");
                } else {
                        /*
                         * Replace the currentdefault config with the new
                         * config
                         */
                        __s_api_init_config(new);
                        chg_config_cookie_increment_seq_num();
                        cout->type = NS_STATUS_CHANGE_TYPE_CONFIG;
                        /*
                         * cout->cookie is set by
                         * chg_notify_statusChange
                         */
                        (void) chg_notify_statusChange((char *)cout);
                }
        } else {
                __s_api_destroy_config(new);
        }

        *change_status = changed;
}

/*
 * Wake up chg_get_statusChange() threads to clean up the threads
 * that main nscd doesn't exist on the other of door anymore or
 * the thread is marked as cleanup.
 */
static void
cleanup_threads(chg_info_t *chg, pid_t pid, cleanup_type_t type)
{
        (void) mutex_lock(&chg->chg_lock);
        if (type == CLEANUP_BY_PID)
                waiting_list_set_cleanup(chg, pid);
        /*
         * wake up threads without setting chg.chg_wakeup.
         * It's for cleanup purpose, not for notifying changes.
         */
        (void) cond_broadcast(&chg->chg_cv);
        (void) mutex_unlock(&chg->chg_lock);
}
/*
 * If arg is NULL, it loops forever,
 * else it calls cleanup_threads once and exits.
 */
void *
chg_cleanup_waiting_threads(void *arg)
{
        cleanup_op_t *op = (cleanup_op_t *)arg;
        cleanup_type_t type = 0;
        pid_t   pid;
        int     always = 1, waiting;

        (void) pthread_setname_np(pthread_self(), "chg_cleanup_thr");

        if (op == NULL) {
                waiting = 1;
                type = CLEANUP_ALL;
                pid = 0;
        } else {
                waiting = 0;
                type = op->type;
                pid = op->pid;
        }

        while (always) {
                if (waiting)
                        (void) sleep(CLEANUP_WAIT_TIME);
                cleanup_threads(&chg, pid, type);
                if (!waiting)
                        break;
        }

        if (op)
                free(op);

        thr_exit(NULL);
        return (NULL);
}
/*
 * The door server thead which has the door client pid will be marked
 * as to be clean up. If pid is 0, no marking and just clean up all.
 */
static void
cleanup_thread_by_pid(pid_t pid)
{
        cleanup_op_t *op;

        if ((op = malloc(sizeof (cleanup_op_t))) == NULL)
                return;

        op->pid = pid;
        /* clean up all if pid is 0 */
        if (pid == 0)
                op->type = CLEANUP_ALL;
        else
                op->type = CLEANUP_BY_PID;

        if (thr_create(NULL, 0, chg_cleanup_waiting_threads,
            (void *)op, THR_BOUND|THR_DETACHED, NULL) != 0) {
                free(op);
                logit("thr_create failed for cleanup_thread_by_pid(%ld)\n",
                    pid);
        }
}

/*
 * Output a psinfo of an nscd process with process id pid
 * Return: 0  - Can't find the process or it's not nscd
 *         1  - psinfo found
 * Note: If info is NULL, returns 0 or 1 only and no output from info.
 */
static int
get_nscd_psinfo(pid_t pid, psinfo_t *info)
{
        psinfo_t        pinfo;
        char            fname[MAXPATHLEN];
        ssize_t         ret;
        int             fd;

        if (snprintf(fname, MAXPATHLEN, "/proc/%d/psinfo", pid) > 0) {
                if ((fd = open(fname,  O_RDONLY)) >= 0) {
                        ret = read(fd, &pinfo, sizeof (psinfo_t));
                        (void) close(fd);
                        if ((ret == sizeof (psinfo_t)) &&
                            (strcmp(pinfo.pr_fname, "nscd") == 0)) {
                                if (info)
                                        *info = pinfo;
                                return (1);
                        }
                }
        }
        return (0);
}
/*
 * If the parent process is nscd and euid is 0, it's a peruser nscd.
 */
static int
is_peruser_nscd(pid_t pid)
{
        pid_t   ppid;
        psinfo_t pinfo;

        if (get_nscd_psinfo(pid, &pinfo)) {
                ppid = pinfo.pr_ppid;
                if (get_nscd_psinfo(ppid, &pinfo) && pinfo.pr_euid == 0)
                        /*
                         * get psinfo of parent forker nscd
                         */
                        return (1);
                else
                        return (0);
        } else {
                return (0);
        }
}
/*
 * Check if the door client making door call is a nscd or peruser nscd and
 * output door client's pid.
 */
int
chg_is_called_from_nscd_or_peruser_nscd(char *dc_str, pid_t *pidp)
{
        int     rc;
        uid_t   euid;
        pid_t   pid;
        ucred_t *uc = NULL;

        if (door_ucred(&uc) != 0) {
                rc = errno;
                logit("door_ucred() call failed %s\n", strerror(rc));
                return (0);
        }
        euid = ucred_geteuid(uc);
        pid = *pidp = ucred_getpid(uc);

        if ((euid == 0 && is_called_from_nscd(pid)) ||
            is_peruser_nscd(pid)) {
                if (current_admin.debug_level >= DBG_ALL)
                        logit("ldap_cachemgr received %s call from pid %ld, "
                            "uid %u, euid %u\n", dc_str, pid,
                            ucred_getruid(uc), euid);
                rc = 1;
        } else {
                if (current_admin.debug_level >= DBG_CANT_FIND)
                        logit("%s call failed(cred): caller pid %ld, uid %u, "
                            "euid %u\n", dc_str, pid,
                            ucred_getruid(uc), euid);

                rc = 0;
        }

        ucred_free(uc);

        return (rc);
}