support/export/xtab.c

   1 /*
   2  * support/export/xtab.c
   3  *
   4  * Interface to the xtab file.
   5  *
   6  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include "config.h"
  10
  11 #include <sys/fcntl.h>
  12 #include <unistd.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include "xmalloc.h"
  16 #include "nfslib.h"
  17 #include "exportfs.h"
  18 #include "xio.h"
  19 #include "xlog.h"
  20
  21 static int
  22 xtab_read(char *xtab, int is_export)
  23 {
  24     /* is_export == 0  => reading /proc/fs/nfs/exports - we know these things are exported to kernel
  25      * is_export == 1  => reading /var/lib/nfs/etab - these things are allowed to be exported
  26      * is_export == 2  => reading /var/lib/nfs/xtab - these things might be known to kernel
  27      */
  28         struct exportent        *xp;
  29         nfs_export              *exp;
  30         int                     lockid;
  31
  32         if ((lockid = xflock(xtab, "r")) < 0)
  33                 return 0;
  34         setexportent(xtab, "r");
  35         while ((xp = getexportent()) != NULL) {
  36                 if (!(exp = export_lookup(xp->e_hostname, xp->e_path)) &&
  37                     !(exp = export_create(xp))) {
  38                         continue;
  39                 }
  40                 switch (is_export) {
  41                 case 0:
  42                         exp->m_exported = 1;
  43                         break;
  44                 case 1:
  45                         exp->m_xtabent = 1;
  46                         exp->m_mayexport = 1;
  47                         break;
  48                 case 2:
  49                         exp->m_exported = -1;/* may be exported */
  50                         break;
  51                 }
  52         }
  53         endexportent();
  54         xfunlock(lockid);
  55
  56         return 0;
  57 }
  58
  59 int
  60 xtab_mount_read(void)
  61 {
  62         int fd;
  63         if ((fd=open(_PATH_PROC_EXPORTS, O_RDONLY))>=0) {
  64                 close(fd);
  65                 return xtab_read(_PATH_PROC_EXPORTS, 0);
  66         } else
  67                 return xtab_read(_PATH_XTAB, 2);
  68 }
  69
  70 int
  71 xtab_export_read(void)
  72 {
  73         return xtab_read(_PATH_ETAB, 1);
  74 }
  75
  76 static int
  77 xtab_write(char *xtab, char *xtabtmp, int is_export)
  78 {
  79         struct exportent        xe;
  80         nfs_export              *exp;
  81         int                     lockid, i;
  82
  83         if ((lockid = xflock(xtab, "w")) < 0) {
  84                 xlog(L_ERROR, "can't lock %s for writing", xtab);
  85                 return 0;
  86         }
  87         setexportent(xtabtmp, "w");
  88
  89         for (i = 0; i < MCL_MAXTYPES; i++) {
  90                 for (exp = exportlist[i]; exp; exp = exp->m_next) {
  91                         if (is_export && !exp->m_xtabent)
  92                                 continue;
  93                         if (!is_export && ! exp->m_exported)
  94                                 continue;
  95
  96                         /* write out the export entry using the FQDN */
  97                         xe = exp->m_export;
  98                         strncpy(xe.e_hostname,
  99                                 exp->m_client->m_hostname,
 100                                 sizeof (xe.e_hostname) - 1);
 101                         xe.e_hostname[sizeof (xe.e_hostname) - 1] = '\0';
 102                         putexportent(&xe);
 103                 }
 104         }
 105         endexportent();
 106
 107         rename(xtabtmp, xtab);
 108
 109         xfunlock(lockid);
 110
 111         return 1;
 112 }
 113
 114 int
 115 xtab_export_write()
 116 {
 117         return xtab_write(_PATH_ETAB, _PATH_ETABTMP, 1);
 118 }
 119
 120 int
 121 xtab_mount_write()
 122 {
 123         return xtab_write(_PATH_XTAB, _PATH_XTABTMP, 0);
 124 }
 125
 126 void
 127 xtab_append(nfs_export *exp)
 128 {
 129         struct exportent xe;
 130         int             lockid;
 131
 132         if ((lockid = xflock(_PATH_XTAB, "w")) < 0)
 133                 return;
 134         setexportent(_PATH_XTAB, "a");
 135         xe = exp->m_export;
 136         strncpy(xe.e_hostname, exp->m_client->m_hostname,
 137                sizeof (xe.e_hostname) - 1);
 138         xe.e_hostname[sizeof (xe.e_hostname) - 1] = '\0';
 139         putexportent(&xe);
 140         endexportent();
 141         xfunlock(lockid);
 142         exp->m_xtabent = 1;
 143 }
 144