minix/lib/libc/sys/shmat.c

   1 #define _SYSTEM 1
   2 #define _MINIX_SYSTEM   1
   3
   4 #include <sys/cdefs.h>
   5 #include <lib.h>
   6 #include "namespace.h"
   7
   8 #include <minix/rs.h>
   9
  10 #include <lib.h>
  11 #include <sys/types.h>
  12 #include <sys/ipc.h>
  13 #include <sys/shm.h>
  14 #include <stdlib.h>
  15 #include <errno.h>
  16 #include <string.h>
  17
  18 static int get_ipc_endpt(endpoint_t *pt)
  19 {
  20         return minix_rs_lookup("ipc", pt);
  21 }
  22
  23 /* Attach shared memory segment. */
  24 void *shmat(int shmid, const void *shmaddr, int shmflg)
  25 {
  26         message m;
  27         endpoint_t ipc_pt;
  28         int r;
  29
  30         if (get_ipc_endpt(&ipc_pt) != OK) {
  31                 errno = ENOSYS;
  32                 return NULL;
  33         }
  34
  35         memset(&m, 0, sizeof(m));
  36         m.m_lc_ipc_shmat.id = shmid;
  37         m.m_lc_ipc_shmat.addr = shmaddr;
  38         m.m_lc_ipc_shmat.flag = shmflg;
  39
  40         r = _syscall(ipc_pt, IPC_SHMAT, &m);
  41         if (r != OK)
  42                 return (void *) -1;
  43         return m.m_lc_ipc_shmat.retaddr;
  44 }
  45
  46 /* Deattach shared memory segment. */
  47 int shmdt(const void *shmaddr)
  48 {
  49         message m;
  50         endpoint_t ipc_pt;
  51
  52         if (get_ipc_endpt(&ipc_pt) != OK) {
  53                 errno = ENOSYS;
  54                 return -1;
  55         }
  56
  57         memset(&m, 0, sizeof(m));
  58         m.m_lc_ipc_shmdt.addr = shmaddr;
  59
  60         return _syscall(ipc_pt, IPC_SHMDT, &m);
  61 }
  62