git.sur5r.net Git - openldap/blob - servers/slapd/back-ldbm/nextid.c

   1 /* id.c - keep track of the next id to be given out */
   2
   3 #include "portable.h"
   4
   5 #include <stdio.h>
   6
   7 #include <ac/socket.h>
   8
   9 #ifdef HAVE_SYS_PARAM_H
  10 #include <sys/param.h>
  11 #endif
  12
  13 #include "slap.h"
  14 #include "back-ldbm.h"
  15
  16 static ID
  17 next_id_read( Backend *be )
  18 {
  19         struct ldbminfo *li = (struct ldbminfo *) be->be_private;
  20         ID      id;
  21         char    buf[20];
  22         char*   file = li->li_nextid_file;
  23         FILE*   fp;
  24
  25         if ( (fp = fopen( file, "r" )) == NULL ) {
  26                 Debug( LDAP_DEBUG_ANY,
  27                     "next_id_read: could not open \"%s\"\n",
  28                     file, 0, 0 );
  29                 return NOID;
  30         }
  31
  32         if ( fgets( buf, sizeof(buf), fp ) == NULL ) {
  33                 Debug( LDAP_DEBUG_ANY,
  34                    "next_id_read: could not fgets nextid from \"%s\"\n",
  35                     file, 0, 0 );
  36                 fclose( fp );
  37                 return NOID;
  38         }
  39
  40         id = atol( buf );
  41         fclose( fp );
  42
  43         if(id < 1) {
  44                 Debug( LDAP_DEBUG_ANY,
  45                         "next_id_read %lu: atol(%s) return non-positive integer\n",
  46                         id, buf, 0 );
  47                 return NOID;
  48         }
  49
  50         return id;
  51 }
  52
  53 static int
  54 next_id_write( Backend *be, ID id )
  55 {
  56         struct ldbminfo *li = (struct ldbminfo *) be->be_private;
  57         char    buf[20];
  58         char*   file = li->li_nextid_file;
  59         FILE*   fp;
  60         int             rc;
  61
  62         if ( (fp = fopen( file, "w" )) == NULL ) {
  63                 Debug( LDAP_DEBUG_ANY, "next_id_write(%lu): could not open \"%s\"\n",
  64                     id, file, 0 );
  65                 return -1;
  66         }
  67
  68         rc = 0;
  69
  70         if ( fprintf( fp, "%ld\n", id ) == EOF ) {
  71                 Debug( LDAP_DEBUG_ANY, "next_id_write(%lu): cannot fprintf\n",
  72                     id, 0, 0 );
  73                 rc = -1;
  74         }
  75
  76         if( fclose( fp ) != 0 ) {
  77                 Debug( LDAP_DEBUG_ANY, "next_id_write %lu: cannot fclose\n",
  78                     id, 0, 0 );
  79                 rc = -1;
  80         }
  81
  82         return rc;
  83 }
  84
  85 ID
  86 next_id( Backend *be )
  87 {
  88         struct ldbminfo *li = (struct ldbminfo *) be->be_private;
  89         ID              id;
  90
  91         pthread_mutex_lock( &li->li_nextid_mutex );
  92
  93         /* first time in here since startup - try to read the nexid */
  94         if ( li->li_nextid == NOID ) {
  95                 li->li_nextid = next_id_read( be );
  96
  97                 if ( li->li_nextid == NOID ) {
  98                         li->li_nextid = 1;
  99                 }
 100         }
 101
 102         id = li->li_nextid++;
 103         (void) next_id_write( be, li->li_nextid );
 104
 105         pthread_mutex_unlock( &li->li_nextid_mutex );
 106         return( id );
 107 }
 108
 109 void
 110 next_id_return( Backend *be, ID id )
 111 {
 112         struct ldbminfo *li = (struct ldbminfo *) be->be_private;
 113
 114         pthread_mutex_lock( &li->li_nextid_mutex );
 115
 116         if ( id != li->li_nextid - 1 ) {
 117                 pthread_mutex_unlock( &li->li_nextid_mutex );
 118                 return;
 119         }
 120
 121         li->li_nextid--;
 122         (void) next_id_write( be, li->li_nextid );
 123
 124         pthread_mutex_unlock( &li->li_nextid_mutex );
 125 }
 126
 127 ID
 128 next_id_get( Backend *be )
 129 {
 130         struct ldbminfo *li = (struct ldbminfo *) be->be_private;
 131         ID              id;
 132
 133         pthread_mutex_lock( &li->li_nextid_mutex );
 134
 135         /* first time in here since startup - try to read the nexid */
 136         if ( li->li_nextid == NOID ) {
 137                 li->li_nextid = next_id_read( be );
 138
 139                 if ( li->li_nextid == NOID ) {
 140                         li->li_nextid = 1;
 141                 }
 142         }
 143
 144         id = li->li_nextid;
 145
 146         pthread_mutex_unlock( &li->li_nextid_mutex );
 147
 148         return( id );
 149 }