path: root/util/uhash_loader.c

/* $Id$ */
/* standalone uhash loader -- jochang */
#include "bbs.h"

unsigned string_hash(unsigned char *s);
void userec_add_to_uhash(int n, userec_t *id, int onfly);
void fill_uhash(int onfly);
void load_uhash(void);

SHM_t *SHM;

int main() {
    setgid(BBSGID);
    setuid(BBSUID);
    chdir(BBSHOME);
    load_uhash();
    return 0;
}

void load_uhash(void) {
    int shmid, err;
    shmid = shmget(SHM_KEY, sizeof(SHM_t), IPC_CREAT | IPC_EXCL | 0600);
    err = errno;
    if( err == EEXIST)
    shmid = shmget(SHM_KEY, sizeof(SHM_t), IPC_CREAT | 0600);
    if (shmid < 0)
    {
    perror("shmget");
    exit(1);
    }
    SHM = (void *) shmat(shmid, NULL, 0);
    if (SHM == (void *) -1)
    {
    perror("shmat");
    exit(1);
    }
    if( err  != EEXIST)
    SHM->number=SHM->loaded = 0;


// in case it's not assumed zero, this becomes a race... 
    if(SHM->number==0 && SHM->loaded == 0)
    {
          SHM->loaded = 0;
          fill_uhash(0);
          SHM->loaded = 1;
    }
    else
        {
         fill_uhash(1); 
        }
}

void checkhash(int h)
{
    int *p = &(SHM->hash_head[h]), ch, deep=0;
    while(*p != -1)
    {
       if(*p <-1 || *p >= MAX_USERS) {*p=-1; return;}
       ch = string_hash( SHM->userid[*p]);
       if(ch!=h)
       {
           printf("remove %d %d!=%d %d [%s] next:%d\n", 
            deep, h, ch, *p, SHM->userid[*p],
            SHM->next_in_hash[*p]);
          *p = SHM->next_in_hash[*p]; //remove from link
          // *p=-1;  Ptt: cut it?
      //return;
       }
       else
          p = &(SHM->next_in_hash[*p]);
       deep++;
    }
}
void fill_uhash(int onfly)
{
    int fd, usernumber;
    usernumber = 0;

    for (fd = 0; fd < (1 << HASH_BITS); fd++)
      if(!onfly)
          SHM->hash_head[fd] = -1;
      else
      checkhash(fd);
    
    if ((fd = open(FN_PASSWD, O_RDWR)) > 0)
    {
    struct stat stbuf;
    caddr_t fimage, mimage;

    fstat(fd, &stbuf);
    fimage = mmap(NULL, stbuf.st_size, PROT_WRITE|PROT_READ, MAP_SHARED, fd, 0);
    if (fimage == (char *) -1)
    {
        perror("mmap");
        exit(1);
    }
    close(fd);
    fd = stbuf.st_size / sizeof(userec_t);
    if (fd > MAX_USERS)
        fd = MAX_USERS;
            
    for (mimage = fimage; usernumber < fd; mimage += sizeof(userec_t))
    {
        userec_add_to_uhash(usernumber, (userec_t *)mimage, onfly);
        usernumber++;
    }
    munmap(fimage, stbuf.st_size);
    }
    else
    {
    perror("open");
    exit(1);
    }
    SHM->number = usernumber;

    printf("total %d names %s.\n", usernumber, onfly ? "checked":"loaded");
}
unsigned string_hash(unsigned char *s)
{
    unsigned int v = 0;
    while (*s)
    {
    v = (v << 8) | (v >> 24);
    v ^= toupper(*s++); /* note this is case insensitive */
    }
    return (v * 2654435769U) >> (32 - HASH_BITS);
}

void userec_add_to_uhash(int n, userec_t *user, int onfly)
{
    int *p, h, l=0;

    h = string_hash(user->userid);
    
    p = &(SHM->hash_head[h]);
    if(!onfly || SHM->userid[n][0] != user->userid[0] || 
           strncmp(SHM->userid[n], user->userid, IDLEN-1))
    {
       strcpy(SHM->userid[n], user->userid);
       SHM->money[n] = user->money;
       if(onfly)
           printf("add %s\n", user->userid);
    }
    while (*p != -1)
    {
    if(onfly && *p==n )  // already in hash
         return;
    l++;
    p = &(SHM->next_in_hash[*p]);
    }
    if(onfly)
       printf("add %d %d %d [%s] in hash\n", l, h, n, user->userid);
    SHM->next_in_hash[*p = n] = -1;
}