lbbs/src/user_list.c

/***************************************************************************
                         user_list.c  -  description
                             -------------------
    Copyright            : (C) 2004-2025 by Leaflet
    Email                : leaflet@leafok.com
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   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 3 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#include "common.h"
#include "database.h"
#include "log.h"
#include "user_list.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/ipc.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/sem.h>
#include <sys/shm.h>

#ifdef _SEM_SEMUN_UNDEFINED
union semun
{
    int val;               /* Value for SETVAL */
    struct semid_ds *buf;  /* Buffer for IPC_STAT, IPC_SET */
    unsigned short *array; /* Array for GETALL, SETALL */
    struct seminfo *__buf; /* Buffer for IPC_INFO
                              (Linux-specific) */
};
#endif // #ifdef _SEM_SEMUN_UNDEFINED

#define USER_LIST_TRY_LOCK_WAIT_TIME 1 // second
#define USER_LIST_TRY_LOCK_TIMES 10

struct user_list_pool_t
{
    int shmid;
    int semid;
    USER_LIST user_list[2];
    USER_LIST *p_current;
    USER_LIST *p_new;
};
typedef struct user_list_pool_t USER_LIST_POOL;

static USER_LIST_POOL *p_user_list_pool = NULL;

static int user_list_try_rd_lock(int semid, int wait_sec);
static int user_list_try_rw_lock(int semid, int wait_sec);
static int user_list_rd_unlock(int semid);
static int user_list_rw_unlock(int semid);
static int user_list_rd_lock(int semid);
static int user_list_rw_lock(int semid);

int user_list_load(MYSQL *db, USER_LIST *p_list)
{
    MYSQL_RES *rs = NULL;
    MYSQL_ROW row;
    char sql[SQL_BUFFER_LEN];
    int ret = 0;
    int i;

    if (db == NULL || p_list == NULL)
    {
        log_error("NULL pointer error\n");
        return -1;
    }

    snprintf(sql, sizeof(sql),
             "SELECT user_list.UID AS UID, username, nickname, gender, gender_pub, life, exp, "
             "UNIX_TIMESTAMP(signup_dt), UNIX_TIMESTAMP(last_login_dt), UNIX_TIMESTAMP(birthday) "
             "FROM user_list INNER JOIN user_pubinfo ON user_list.UID = user_pubinfo.UID "
             "INNER JOIN user_reginfo ON user_list.UID = user_reginfo.UID "
             "WHERE enable ORDER BY UID");

    if (mysql_query(db, sql) != 0)
    {
        log_error("Query user info error: %s\n", mysql_error(db));
        ret = -1;
        goto cleanup;
    }

    if ((rs = mysql_use_result(db)) == NULL)
    {
        log_error("Get user info data failed\n");
        ret = -1;
        goto cleanup;
    }

    i = 0;
    while ((row = mysql_fetch_row(rs)))
    {
        p_list->users[i].uid = atoi(row[0]);
        strncpy(p_list->users[i].username, row[1], sizeof(p_list->users[i].username) - 1);
        p_list->users[i].username[sizeof(p_list->users[i].username) - 1] = '\0';
        strncpy(p_list->users[i].nickname, row[2], sizeof(p_list->users[i].nickname) - 1);
        p_list->users[i].nickname[sizeof(p_list->users[i].nickname) - 1] = '\0';
        p_list->users[i].gender = row[3][0];
        p_list->users[i].gender_pub = (int8_t)(row[4] == NULL ? 0 : atoi(row[4]));
        p_list->users[i].life = (row[5] == NULL ? 0 : atoi(row[5]));
        p_list->users[i].exp = (row[6] == NULL ? 0 : atoi(row[6]));
        p_list->users[i].signup_dt = (row[7] == NULL ? 0 : atol(row[7]));
        p_list->users[i].last_login_dt = (row[8] == NULL ? 0 : atol(row[8]));
        p_list->users[i].birthday = (row[9] == NULL ? 0 : atol(row[9]));

        i++;
        if (i >= BBS_max_user_count)
        {
            log_error("Too many users, exceed limit %d\n", BBS_max_user_count);
            break;
        }
    }
    mysql_free_result(rs);
    rs = NULL;

    p_list->user_count = i;

#ifdef _DEBUG
    log_error("Loaded %d users\n", p_list->user_count);
#endif

cleanup:
    mysql_free_result(rs);

    return ret;
}

int user_list_pool_init(void)
{
    int shmid;
    int semid;
    int proj_id;
    key_t key;
    size_t size;
    void *p_shm;
    union semun arg;
    int i;

    if (p_user_list_pool != NULL)
    {
        log_error("p_user_list_pool already initialized\n");
        return -1;
    }

    // Allocate shared memory
    proj_id = (int)(time(NULL) % getpid());
    key = ftok(VAR_USER_LIST_SHM, proj_id);
    if (key == -1)
    {
        log_error("ftok(%s %d) error (%d)\n", VAR_USER_LIST_SHM, proj_id, errno);
        return -2;
    }

    size = sizeof(USER_LIST_POOL);
    shmid = shmget(key, size, IPC_CREAT | IPC_EXCL | 0600);
    if (shmid == -1)
    {
        log_error("shmget(size = %d) error (%d)\n", size, errno);
        return -3;
    }
    p_shm = shmat(shmid, NULL, 0);
    if (p_shm == (void *)-1)
    {
        log_error("shmat(shmid=%d) error (%d)\n", shmid, errno);
        return -3;
    }

    p_user_list_pool = p_shm;
    p_user_list_pool->shmid = shmid;

    // Allocate semaphore as user list pool lock
    size = 2; // r_sem and w_sem
    semid = semget(key, (int)size, IPC_CREAT | IPC_EXCL | 0600);
    if (semid == -1)
    {
        log_error("semget(user_list_pool_sem, size = %d) error (%d)\n", size, errno);
        return -3;
    }

    // Initialize sem value to 0
    arg.val = 0;
    for (i = 0; i < size; i++)
    {
        if (semctl(semid, i, SETVAL, arg) == -1)
        {
            log_error("semctl(user_list_pool_sem, SETVAL) error (%d)\n", errno);
            return -3;
        }
    }

    p_user_list_pool->semid = semid;

    // Set user counts to 0
    p_user_list_pool->user_list[0].user_count = 0;
    p_user_list_pool->user_list[1].user_count = 0;

    p_user_list_pool->p_current = &(p_user_list_pool->user_list[0]);
    p_user_list_pool->p_new = &(p_user_list_pool->user_list[1]);

    return 0;
}

void user_list_pool_cleanup(void)
{
    int shmid;

    if (p_user_list_pool == NULL)
    {
        return;
    }

    shmid = p_user_list_pool->shmid;

    if (semctl(p_user_list_pool->semid, 0, IPC_RMID) == -1)
    {
        log_error("semctl(semid = %d, IPC_RMID) error (%d)\n", p_user_list_pool->semid, errno);
    }

    if (shmdt(p_user_list_pool) == -1)
    {
        log_error("shmdt(shmid = %d) error (%d)\n", shmid, errno);
    }

    if (shmctl(shmid, IPC_RMID, NULL) == -1)
    {
        log_error("shmctl(shmid = %d, IPC_RMID) error (%d)\n", shmid, errno);
    }

    p_user_list_pool = NULL;
}

int set_user_list_pool_shm_readonly(void)
{
    int shmid;
    void *p_shm;

    if (p_user_list_pool == NULL)
    {
        log_error("p_user_list_pool not initialized\n");
        return -1;
    }

    shmid = p_user_list_pool->shmid;

    // Remap shared memory in read-only mode
    p_shm = shmat(shmid, p_user_list_pool, SHM_RDONLY | SHM_REMAP);
    if (p_shm == (void *)-1)
    {
        log_error("shmat(user_list_pool shmid = %d) error (%d)\n", shmid, errno);
        return -3;
    }

    p_user_list_pool = p_shm;

    return 0;
}

int detach_user_list_pool_shm(void)
{
    if (p_user_list_pool != NULL && shmdt(p_user_list_pool) == -1)
    {
        log_error("shmdt(user_list_pool) error (%d)\n", errno);
        return -1;
    }

    p_user_list_pool = NULL;

    return 0;
}

int user_list_pool_reload(void)
{
    MYSQL *db = NULL;
    USER_LIST *p_tmp;

    if (p_user_list_pool == NULL)
    {
        log_error("p_user_list_pool not initialized\n");
        return -1;
    }

    db = db_open();
    if (db == NULL)
    {
        log_error("db_open() error: %s\n", mysql_error(db));
        return -1;
    }

    if (user_list_load(db, p_user_list_pool->p_new) < 0)
    {
        log_error("user_list_rw_lock() error\n");
        return -2;
    }

    mysql_close(db);

    if (user_list_rw_lock(p_user_list_pool->semid) < 0)
    {
        log_error("user_list_rw_lock() error\n");
        return -3;
    }

    // Swap p_current and p_new
    p_tmp = p_user_list_pool->p_current;
    p_user_list_pool->p_current = p_user_list_pool->p_new;
    p_user_list_pool->p_new = p_tmp;

    if (user_list_rw_unlock(p_user_list_pool->semid) < 0)
    {
        log_error("user_list_rw_unlock() error\n");
        return -3;
    }

    return 0;
}

int user_list_try_rd_lock(int semid, int wait_sec)
{
    struct sembuf sops[2];
    struct timespec timeout;
    int ret;

    sops[0].sem_num = 1; // w_sem
    sops[0].sem_op = 0;  // wait until unlocked
    sops[0].sem_flg = 0;

    sops[1].sem_num = 0;        // r_sem
    sops[1].sem_op = 1;         // lock
    sops[1].sem_flg = SEM_UNDO; // undo on terminate

    timeout.tv_sec = wait_sec;
    timeout.tv_nsec = 0;

    ret = semtimedop(semid, sops, 2, &timeout);
    if (ret == -1 && errno != EAGAIN && errno != EINTR)
    {
        log_error("semtimedop(lock read) error %d\n", errno);
    }

    return ret;
}

int user_list_try_rw_lock(int semid, int wait_sec)
{
    struct sembuf sops[3];
    struct timespec timeout;
    int ret;

    sops[0].sem_num = 1; // w_sem
    sops[0].sem_op = 0;  // wait until unlocked
    sops[0].sem_flg = 0;

    sops[1].sem_num = 1;        // w_sem
    sops[1].sem_op = 1;         // lock
    sops[1].sem_flg = SEM_UNDO; // undo on terminate

    sops[2].sem_num = 0; // r_sem
    sops[2].sem_op = 0;  // wait until unlocked
    sops[2].sem_flg = 0;

    timeout.tv_sec = wait_sec;
    timeout.tv_nsec = 0;

    ret = semtimedop(semid, sops, 3, &timeout);
    if (ret == -1 && errno != EAGAIN && errno != EINTR)
    {
        log_error("semtimedop(lock write) error %d\n", errno);
    }

    return ret;
}

int user_list_rd_unlock(int semid)
{
    struct sembuf sops[2];
    int ret;

    sops[0].sem_num = 0;                     // r_sem
    sops[0].sem_op = -1;                     // unlock
    sops[0].sem_flg = IPC_NOWAIT | SEM_UNDO; // no wait

    ret = semop(semid, sops, 1);
    if (ret == -1 && errno != EAGAIN && errno != EINTR)
    {
        log_error("semop(unlock read) error %d\n", errno);
    }

    return ret;
}

int user_list_rw_unlock(int semid)
{
    struct sembuf sops[1];
    int ret;

    sops[0].sem_num = 1;                     // w_sem
    sops[0].sem_op = -1;                     // unlock
    sops[0].sem_flg = IPC_NOWAIT | SEM_UNDO; // no wait

    ret = semop(semid, sops, 1);
    if (ret == -1 && errno != EAGAIN && errno != EINTR)
    {
        log_error("semop(unlock write) error %d\n", errno);
    }

    return ret;
}

int user_list_rd_lock(int semid)
{
    int timer = 0;
    int ret = -1;

    while (!SYS_server_exit)
    {
        ret = user_list_try_rd_lock(semid, USER_LIST_TRY_LOCK_WAIT_TIME);
        if (ret == 0) // success
        {
            break;
        }
        else if (errno == EAGAIN || errno == EINTR) // retry
        {
            timer++;
            if (timer % USER_LIST_TRY_LOCK_TIMES == 0)
            {
                log_error("user_list_try_rd_lock() tried %d times\n", timer);
            }
        }
        else // failed
        {
            log_error("user_list_try_rd_lock() failed\n");
            break;
        }
    }

    return ret;
}

int user_list_rw_lock(int semid)
{
    int timer = 0;
    int ret = -1;

    while (!SYS_server_exit)
    {
        ret = user_list_try_rw_lock(semid, USER_LIST_TRY_LOCK_WAIT_TIME);
        if (ret == 0) // success
        {
            break;
        }
        else if (errno == EAGAIN || errno == EINTR) // retry
        {
            timer++;
            if (timer % USER_LIST_TRY_LOCK_TIMES == 0)
            {
                log_error("user_list_try_rw_lock() tried %d times\n", timer);
            }
        }
        else // failed
        {
            log_error("user_list_try_rw_lock() failed\n");
            break;
        }
    }

    return ret;
}

int query_user_list(int page_id, USER_INFO *p_users, int *p_user_count, int *p_page_count)
{
    int ret = 0;

    if (p_users == NULL || p_user_count == NULL || p_page_count == NULL)
    {
        log_error("NULL pointer error\n");
        return -1;
    }

    // acquire lock of user list
    if (user_list_rd_lock(p_user_list_pool->semid) < 0)
    {
        log_error("user_list_rd_lock() error\n");
        return -2;
    }

    if (p_user_list_pool->p_current->user_count == 0)
    {
        // empty list
        ret = 0;
        goto cleanup;
    }

    *p_page_count = p_user_list_pool->p_current->user_count / BBS_user_limit_per_page +
                    (p_user_list_pool->p_current->user_count % BBS_user_limit_per_page == 0 ? 0 : 1);

    if (page_id < 0 || page_id >= *p_page_count)
    {
        log_error("Invalid page_id = %d, not in range [0, %d)\n", page_id, *p_page_count);
        ret = -3;
        goto cleanup;
    }

    *p_user_count = MIN(BBS_user_limit_per_page,
                        p_user_list_pool->p_current->user_count -
                            page_id * BBS_user_limit_per_page);

    memcpy(p_users,
           p_user_list_pool->p_current->users + page_id * BBS_user_limit_per_page,
           sizeof(USER_INFO) * (size_t)(*p_user_count));

cleanup:
    // release lock of user list
    if (user_list_rd_unlock(p_user_list_pool->semid) < 0)
    {
        log_error("user_list_rd_unlock() error\n");
        ret = -1;
    }

    return ret;
}

int query_user_info(int32_t uid, USER_INFO *p_user)
{
    int left;
    int right;
    int mid;
    int ret = 0;

    if (p_user == NULL)
    {
        log_error("NULL pointer error\n");
        return -1;
    }

    // acquire lock of user list
    if (user_list_rd_lock(p_user_list_pool->semid) < 0)
    {
        log_error("user_list_rd_lock() error\n");
        return -2;
    }

    left = 0;
    right = p_user_list_pool->p_current->user_count - 1;

    while (left < right)
    {
        mid = (left + right) / 2;
        if (uid < p_user_list_pool->p_current->users[mid].uid)
        {
            right = mid;
        }
        else if (uid > p_user_list_pool->p_current->users[mid].uid)
        {
            left = mid + 1;
        }
        else // if (uid == p_user_list_pool->p_current->users[mid].uid)
        {
            left = mid;
            break;
        }
    }

    if (uid == p_user_list_pool->p_current->users[left].uid) // Found
    {
        *p_user = p_user_list_pool->p_current->users[left];
        ret = 1;
    }

    // release lock of user list
    if (user_list_rd_unlock(p_user_list_pool->semid) < 0)
    {
        log_error("user_list_rd_unlock() error\n");
        ret = -1;
    }

    return ret;
}
1	/***************************************************************************
2	user_list.c - description
3	-------------------
4	Copyright : (C) 2004-2025 by Leaflet
5	Email : leaflet@leafok.com
6	***************************************************************************/
7
8	/***************************************************************************
9	* *
10	* This program is free software; you can redistribute it and/or modify *
11	* it under the terms of the GNU General Public License as published by *
12	* the Free Software Foundation; either version 3 of the License, or *
13	* (at your option) any later version. *
14	* *
15	***************************************************************************/
16
17	#include "common.h"
18	#include "database.h"
19	#include "log.h"
20	#include "user_list.h"
21	#include <errno.h>
22	#include <stdlib.h>
23	#include <string.h>
24	#include <time.h>
25	#include <sys/ipc.h>
26	#include <sys/mman.h>
27	#include <sys/param.h>
28	#include <sys/sem.h>
29	#include <sys/shm.h>
30
31	#ifdef _SEM_SEMUN_UNDEFINED
32	union semun
33	{
34	int val; /* Value for SETVAL */
35	struct semid_ds buf; / Buffer for IPC_STAT, IPC_SET */
36	unsigned short array; / Array for GETALL, SETALL */
37	struct seminfo __buf; / Buffer for IPC_INFO
38	(Linux-specific) */
39	};
40	#endif // #ifdef _SEM_SEMUN_UNDEFINED
41
42	#define USER_LIST_TRY_LOCK_WAIT_TIME 1 // second
43	#define USER_LIST_TRY_LOCK_TIMES 10
44
45	struct user_list_pool_t
46	{
47	int shmid;
48	int semid;
49	USER_LIST user_list[2];
50	USER_LIST *p_current;
51	USER_LIST *p_new;
52	};
53	typedef struct user_list_pool_t USER_LIST_POOL;
54
55	static USER_LIST_POOL *p_user_list_pool = NULL;
56
57	static int user_list_try_rd_lock(int semid, int wait_sec);
58	static int user_list_try_rw_lock(int semid, int wait_sec);
59	static int user_list_rd_unlock(int semid);
60	static int user_list_rw_unlock(int semid);
61	static int user_list_rd_lock(int semid);
62	static int user_list_rw_lock(int semid);
63
64	int user_list_load(MYSQL db, USER_LIST p_list)
65	{
66	MYSQL_RES *rs = NULL;
67	MYSQL_ROW row;
68	char sql[SQL_BUFFER_LEN];
69	int ret = 0;
70	int i;
71
72	if (db == NULL \|\| p_list == NULL)
73	{
74	log_error("NULL pointer error\n");
75	return -1;
76	}
77
78	snprintf(sql, sizeof(sql),
79	"SELECT user_list.UID AS UID, username, nickname, gender, gender_pub, life, exp, "
80	"UNIX_TIMESTAMP(signup_dt), UNIX_TIMESTAMP(last_login_dt), UNIX_TIMESTAMP(birthday) "
81	"FROM user_list INNER JOIN user_pubinfo ON user_list.UID = user_pubinfo.UID "
82	"INNER JOIN user_reginfo ON user_list.UID = user_reginfo.UID "
83	"WHERE enable ORDER BY UID");
84
85	if (mysql_query(db, sql) != 0)
86	{
87	log_error("Query user info error: %s\n", mysql_error(db));
88	ret = -1;
89	goto cleanup;
90	}
91
92	if ((rs = mysql_use_result(db)) == NULL)
93	{
94	log_error("Get user info data failed\n");
95	ret = -1;
96	goto cleanup;
97	}
98
99	i = 0;
100	while ((row = mysql_fetch_row(rs)))
101	{
102	p_list->users[i].uid = atoi(row[0]);
103	strncpy(p_list->users[i].username, row[1], sizeof(p_list->users[i].username) - 1);
104	p_list->users[i].username[sizeof(p_list->users[i].username) - 1] = '\0';
105	strncpy(p_list->users[i].nickname, row[2], sizeof(p_list->users[i].nickname) - 1);
106	p_list->users[i].nickname[sizeof(p_list->users[i].nickname) - 1] = '\0';
107	p_list->users[i].gender = row[3][0];
108	p_list->users[i].gender_pub = (int8_t)(row[4] == NULL ? 0 : atoi(row[4]));
109	p_list->users[i].life = (row[5] == NULL ? 0 : atoi(row[5]));
110	p_list->users[i].exp = (row[6] == NULL ? 0 : atoi(row[6]));
111	p_list->users[i].signup_dt = (row[7] == NULL ? 0 : atol(row[7]));
112	p_list->users[i].last_login_dt = (row[8] == NULL ? 0 : atol(row[8]));
113	p_list->users[i].birthday = (row[9] == NULL ? 0 : atol(row[9]));
114
115	i++;
116	if (i >= BBS_max_user_count)
117	{
118	log_error("Too many users, exceed limit %d\n", BBS_max_user_count);
119	break;
120	}
121	}
122	mysql_free_result(rs);
123	rs = NULL;
124
125	p_list->user_count = i;
126
127	#ifdef _DEBUG
128	log_error("Loaded %d users\n", p_list->user_count);
129	#endif
130
131	cleanup:
132	mysql_free_result(rs);
133
134	return ret;
135	}
136
137	int user_list_pool_init(void)
138	{
139	int shmid;
140	int semid;
141	int proj_id;
142	key_t key;
143	size_t size;
144	void *p_shm;
145	union semun arg;
146	int i;
147
148	if (p_user_list_pool != NULL)
149	{
150	log_error("p_user_list_pool already initialized\n");
151	return -1;
152	}
153
154	// Allocate shared memory
155	proj_id = (int)(time(NULL) % getpid());
156	key = ftok(VAR_USER_LIST_SHM, proj_id);
157	if (key == -1)
158	{
159	log_error("ftok(%s %d) error (%d)\n", VAR_USER_LIST_SHM, proj_id, errno);
160	return -2;
161	}
162
163	size = sizeof(USER_LIST_POOL);
164	shmid = shmget(key, size, IPC_CREAT \| IPC_EXCL \| 0600);
165	if (shmid == -1)
166	{
167	log_error("shmget(size = %d) error (%d)\n", size, errno);
168	return -3;
169	}
170	p_shm = shmat(shmid, NULL, 0);
171	if (p_shm == (void *)-1)
172	{
173	log_error("shmat(shmid=%d) error (%d)\n", shmid, errno);
174	return -3;
175	}
176
177	p_user_list_pool = p_shm;
178	p_user_list_pool->shmid = shmid;
179
180	// Allocate semaphore as user list pool lock
181	size = 2; // r_sem and w_sem
182	semid = semget(key, (int)size, IPC_CREAT \| IPC_EXCL \| 0600);
183	if (semid == -1)
184	{
185	log_error("semget(user_list_pool_sem, size = %d) error (%d)\n", size, errno);
186	return -3;
187	}
188
189	// Initialize sem value to 0
190	arg.val = 0;
191	for (i = 0; i < size; i++)
192	{
193	if (semctl(semid, i, SETVAL, arg) == -1)
194	{
195	log_error("semctl(user_list_pool_sem, SETVAL) error (%d)\n", errno);
196	return -3;
197	}
198	}
199
200	p_user_list_pool->semid = semid;
201
202	// Set user counts to 0
203	p_user_list_pool->user_list[0].user_count = 0;
204	p_user_list_pool->user_list[1].user_count = 0;
205
206	p_user_list_pool->p_current = &(p_user_list_pool->user_list[0]);
207	p_user_list_pool->p_new = &(p_user_list_pool->user_list[1]);
208
209	return 0;
210	}
211
212	void user_list_pool_cleanup(void)
213	{
214	int shmid;
215
216	if (p_user_list_pool == NULL)
217	{
218	return;
219	}
220
221	shmid = p_user_list_pool->shmid;
222
223	if (semctl(p_user_list_pool->semid, 0, IPC_RMID) == -1)
224	{
225	log_error("semctl(semid = %d, IPC_RMID) error (%d)\n", p_user_list_pool->semid, errno);
226	}
227
228	if (shmdt(p_user_list_pool) == -1)
229	{
230	log_error("shmdt(shmid = %d) error (%d)\n", shmid, errno);
231	}
232
233	if (shmctl(shmid, IPC_RMID, NULL) == -1)
234	{
235	log_error("shmctl(shmid = %d, IPC_RMID) error (%d)\n", shmid, errno);
236	}
237
238	p_user_list_pool = NULL;
239	}
240
241	int set_user_list_pool_shm_readonly(void)
242	{
243	int shmid;
244	void *p_shm;
245
246	if (p_user_list_pool == NULL)
247	{
248	log_error("p_user_list_pool not initialized\n");
249	return -1;
250	}
251
252	shmid = p_user_list_pool->shmid;
253
254	// Remap shared memory in read-only mode
255	p_shm = shmat(shmid, p_user_list_pool, SHM_RDONLY \| SHM_REMAP);
256	if (p_shm == (void *)-1)
257	{
258	log_error("shmat(user_list_pool shmid = %d) error (%d)\n", shmid, errno);
259	return -3;
260	}
261
262	p_user_list_pool = p_shm;
263
264	return 0;
265	}
266
267	int detach_user_list_pool_shm(void)
268	{
269	if (p_user_list_pool != NULL && shmdt(p_user_list_pool) == -1)
270	{
271	log_error("shmdt(user_list_pool) error (%d)\n", errno);
272	return -1;
273	}
274
275	p_user_list_pool = NULL;
276
277	return 0;
278	}
279
280	int user_list_pool_reload(void)
281	{
282	MYSQL *db = NULL;
283	USER_LIST *p_tmp;
284
285	if (p_user_list_pool == NULL)
286	{
287	log_error("p_user_list_pool not initialized\n");
288	return -1;
289	}
290
291	db = db_open();
292	if (db == NULL)
293	{
294	log_error("db_open() error: %s\n", mysql_error(db));
295	return -1;
296	}
297
298	if (user_list_load(db, p_user_list_pool->p_new) < 0)
299	{
300	log_error("user_list_rw_lock() error\n");
301	return -2;
302	}
303
304	mysql_close(db);
305
306	if (user_list_rw_lock(p_user_list_pool->semid) < 0)
307	{
308	log_error("user_list_rw_lock() error\n");
309	return -3;
310	}
311
312	// Swap p_current and p_new
313	p_tmp = p_user_list_pool->p_current;
314	p_user_list_pool->p_current = p_user_list_pool->p_new;
315	p_user_list_pool->p_new = p_tmp;
316
317	if (user_list_rw_unlock(p_user_list_pool->semid) < 0)
318	{
319	log_error("user_list_rw_unlock() error\n");
320	return -3;
321	}
322
323	return 0;
324	}
325
326	int user_list_try_rd_lock(int semid, int wait_sec)
327	{
328	struct sembuf sops[2];
329	struct timespec timeout;
330	int ret;
331
332	sops[0].sem_num = 1; // w_sem
333	sops[0].sem_op = 0; // wait until unlocked
334	sops[0].sem_flg = 0;
335
336	sops[1].sem_num = 0; // r_sem
337	sops[1].sem_op = 1; // lock
338	sops[1].sem_flg = SEM_UNDO; // undo on terminate
339
340	timeout.tv_sec = wait_sec;
341	timeout.tv_nsec = 0;
342
343	ret = semtimedop(semid, sops, 2, &timeout);
344	if (ret == -1 && errno != EAGAIN && errno != EINTR)
345	{
346	log_error("semtimedop(lock read) error %d\n", errno);
347	}
348
349	return ret;
350	}
351
352	int user_list_try_rw_lock(int semid, int wait_sec)
353	{
354	struct sembuf sops[3];
355	struct timespec timeout;
356	int ret;
357
358	sops[0].sem_num = 1; // w_sem
359	sops[0].sem_op = 0; // wait until unlocked
360	sops[0].sem_flg = 0;
361
362	sops[1].sem_num = 1; // w_sem
363	sops[1].sem_op = 1; // lock
364	sops[1].sem_flg = SEM_UNDO; // undo on terminate
365
366	sops[2].sem_num = 0; // r_sem
367	sops[2].sem_op = 0; // wait until unlocked
368	sops[2].sem_flg = 0;
369
370	timeout.tv_sec = wait_sec;
371	timeout.tv_nsec = 0;
372
373	ret = semtimedop(semid, sops, 3, &timeout);
374	if (ret == -1 && errno != EAGAIN && errno != EINTR)
375	{
376	log_error("semtimedop(lock write) error %d\n", errno);
377	}
378
379	return ret;
380	}
381
382	int user_list_rd_unlock(int semid)
383	{
384	struct sembuf sops[2];
385	int ret;
386
387	sops[0].sem_num = 0; // r_sem
388	sops[0].sem_op = -1; // unlock
389	sops[0].sem_flg = IPC_NOWAIT \| SEM_UNDO; // no wait
390
391	ret = semop(semid, sops, 1);
392	if (ret == -1 && errno != EAGAIN && errno != EINTR)
393	{
394	log_error("semop(unlock read) error %d\n", errno);
395	}
396
397	return ret;
398	}
399
400	int user_list_rw_unlock(int semid)
401	{
402	struct sembuf sops[1];
403	int ret;
404
405	sops[0].sem_num = 1; // w_sem
406	sops[0].sem_op = -1; // unlock
407	sops[0].sem_flg = IPC_NOWAIT \| SEM_UNDO; // no wait
408
409	ret = semop(semid, sops, 1);
410	if (ret == -1 && errno != EAGAIN && errno != EINTR)
411	{
412	log_error("semop(unlock write) error %d\n", errno);
413	}
414
415	return ret;
416	}
417
418	int user_list_rd_lock(int semid)
419	{
420	int timer = 0;
421	int ret = -1;
422
423	while (!SYS_server_exit)
424	{
425	ret = user_list_try_rd_lock(semid, USER_LIST_TRY_LOCK_WAIT_TIME);
426	if (ret == 0) // success
427	{
428	break;
429	}
430	else if (errno == EAGAIN \|\| errno == EINTR) // retry
431	{
432	timer++;
433	if (timer % USER_LIST_TRY_LOCK_TIMES == 0)
434	{
435	log_error("user_list_try_rd_lock() tried %d times\n", timer);
436	}
437	}
438	else // failed
439	{
440	log_error("user_list_try_rd_lock() failed\n");
441	break;
442	}
443	}
444
445	return ret;
446	}
447
448	int user_list_rw_lock(int semid)
449	{
450	int timer = 0;
451	int ret = -1;
452
453	while (!SYS_server_exit)
454	{
455	ret = user_list_try_rw_lock(semid, USER_LIST_TRY_LOCK_WAIT_TIME);
456	if (ret == 0) // success
457	{
458	break;
459	}
460	else if (errno == EAGAIN \|\| errno == EINTR) // retry
461	{
462	timer++;
463	if (timer % USER_LIST_TRY_LOCK_TIMES == 0)
464	{
465	log_error("user_list_try_rw_lock() tried %d times\n", timer);
466	}
467	}
468	else // failed
469	{
470	log_error("user_list_try_rw_lock() failed\n");
471	break;
472	}
473	}
474
475	return ret;
476	}
477
478	int query_user_list(int page_id, USER_INFO p_users, int p_user_count, int *p_page_count)
479	{
480	int ret = 0;
481
482	if (p_users == NULL \|\| p_user_count == NULL \|\| p_page_count == NULL)
483	{
484	log_error("NULL pointer error\n");
485	return -1;
486	}
487
488	// acquire lock of user list
489	if (user_list_rd_lock(p_user_list_pool->semid) < 0)
490	{
491	log_error("user_list_rd_lock() error\n");
492	return -2;
493	}
494
495	if (p_user_list_pool->p_current->user_count == 0)
496	{
497	// empty list
498	ret = 0;
499	goto cleanup;
500	}
501
502	*p_page_count = p_user_list_pool->p_current->user_count / BBS_user_limit_per_page +
503	(p_user_list_pool->p_current->user_count % BBS_user_limit_per_page == 0 ? 0 : 1);
504
505	if (page_id < 0 \|\| page_id >= *p_page_count)
506	{
507	log_error("Invalid page_id = %d, not in range [0, %d)\n", page_id, *p_page_count);
508	ret = -3;
509	goto cleanup;
510	}
511
512	*p_user_count = MIN(BBS_user_limit_per_page,
513	p_user_list_pool->p_current->user_count -
514	page_id * BBS_user_limit_per_page);
515
516	memcpy(p_users,
517	p_user_list_pool->p_current->users + page_id * BBS_user_limit_per_page,
518	sizeof(USER_INFO) * (size_t)(*p_user_count));
519
520	cleanup:
521	// release lock of user list
522	if (user_list_rd_unlock(p_user_list_pool->semid) < 0)
523	{
524	log_error("user_list_rd_unlock() error\n");
525	ret = -1;
526	}
527
528	return ret;
529	}
530
531	int query_user_info(int32_t uid, USER_INFO *p_user)
532	{
533	int left;
534	int right;
535	int mid;
536	int ret = 0;
537
538	if (p_user == NULL)
539	{
540	log_error("NULL pointer error\n");
541	return -1;
542	}
543
544	// acquire lock of user list
545	if (user_list_rd_lock(p_user_list_pool->semid) < 0)
546	{
547	log_error("user_list_rd_lock() error\n");
548	return -2;
549	}
550
551	left = 0;
552	right = p_user_list_pool->p_current->user_count - 1;
553
554	while (left < right)
555	{
556	mid = (left + right) / 2;
557	if (uid < p_user_list_pool->p_current->users[mid].uid)
558	{
559	right = mid;
560	}
561	else if (uid > p_user_list_pool->p_current->users[mid].uid)
562	{
563	left = mid + 1;
564	}
565	else // if (uid == p_user_list_pool->p_current->users[mid].uid)
566	{
567	left = mid;
568	break;
569	}
570	}
571
572	if (uid == p_user_list_pool->p_current->users[left].uid) // Found
573	{
574	*p_user = p_user_list_pool->p_current->users[left];
575	ret = 1;
576	}
577
578	// release lock of user list
579	if (user_list_rd_unlock(p_user_list_pool->semid) < 0)
580	{
581	log_error("user_list_rd_unlock() error\n");
582	ret = -1;
583	}
584
585	return ret;
586	}
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