apps/lib/stdlibc/sem.c

   1 /*
   2     meinOS - A unix-like x86 microkernel operating system
   3     Copyright (C) 2008  Janosch Gräf <janosch.graef@gmx.net>
   4
   5     This program is free software: you can redistribute it and/or modify
   6     it under the terms of the GNU Lesser General Public License as published by
   7     the Free Software Foundation, either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU Lesser General Public License for more details.
  14
  15     You should have received a copy of the GNU Lesser General Public License
  16     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #include <sys/sem.h>
  20 #include <sys/ipc.h>
  21 #include <sys/types.h>
  22 #include <time.h>
  23 #include <stdarg.h>
  24 #include <errno.h>
  25 #include <syscall.h>
  26
  27 #define sem_get(key)                                          syscall_call(SYSCALL_IPC_SEM_GET,1,key)
  28 #define sem_create(key,nsems,flags)                           syscall_call(SYSCALL_IPC_SEM_CREATE,4,key,nsems,flags,time(NULL))
  29 #define sem_op(id,ops,nops)                                   syscall_call(SYSCALL_IPC_SEM_OP,4,id,ops,nops,time(NULL))
  30 #define sem_getval(id,num)                                    syscall_call(SYSCALL_IPC_SEM_GETVAL,2,id,num)
  31 #define sem_setval(id,num,val)                                syscall_call(SYSCALL_IPC_SEM_SETVAL,4,id,num,val,time(NULL))
  32 #define sem_getpid(id,num)                                    syscall_call(SYSCALL_IPC_SEM_GETPID,2,id,num)
  33 #define sem_getcnt(id,num,type)                               syscall_call(SYSCALL_IPC_SEM_GETCNT,3,id,num,type)
  34 #define sem_getall(id,buf)                                    syscall_call(SYSCALL_IPC_SEM_GETALL,2,id,buf)
  35 #define sem_setall(id,buf)                                    syscall_call(SYSCALL_IPC_SEM_SETALL,3,id,buf,time(NULL))
  36 #define sem_stat(id,uid,gid,cuid,cgid,mode,nsems,otime,ctime) syscall_call(SYSCALL_IPC_SEM_STAT,9,id,uid,gid,cuid,cgid,mode,nsems,otime,ctime)
  37 #define sem_set(id,uid,gid,mode)                              syscall_call(SYSCALL_IPC_SEM_SET,5,id,uid,gid,mode,time(NULL))
  38 #define sem_destroy(id)                                       syscall_call(SYSCALL_IPC_SEM_DESTROY,1,id)
  39
  40 int semget(key_t key,int nsems,int flags) {
  41   int ret;
  42   if ((flags&IPC_CREAT) || key==IPC_PRIVATE) ret = sem_create(key,nsems,flags&0777);
  43   if (!(flags&IPC_CREAT) || ret<0) ret = sem_get(key);
  44   errno = ret<0?-ret:0;
  45   return ret<0?-1:ret;
  46 }
  47
  48 int semop(int id,struct sembuf *ops,size_t nops) {
  49   ssize_t ret;
  50   do {
  51     int sleep = 0;
  52     ret = sem_op(id,ops,nops);
  53     while (sleep);
  54     if (ret<0) {
  55       errno = ret;
  56       return -1;
  57     }
  58   }
  59   while (ret<nops);
  60   errno = 0;
  61   return 0;
  62 }
  63
  64 int semctl(int id,int num,int cmd,...) {
  65   va_list args;
  66   int ret;
  67
  68   va_start(args,cmd);
  69   if (cmd==GETVAL) ret = sem_getval(id,num);
  70   else if (cmd==SETVAL) ret = sem_setval(id,num,va_arg(args,int));
  71   else if (cmd==GETPID) ret = sem_getpid(id,num);
  72   else if (cmd==GETNCNT) ret = sem_getcnt(id,num,'n');
  73   else if (cmd==GETZCNT) ret = sem_getcnt(id,num,'z');
  74   else if (cmd==GETALL) ret = sem_getall(id,va_arg(args,unsigned short*));
  75   else if (cmd==SETALL) ret = sem_setall(id,va_arg(args,unsigned short*));
  76   else if (cmd==IPC_STAT) {
  77     struct semid_ds *buf = va_arg(args,struct semid_ds*);
  78     ret = sem_stat(id,&(buf->sem_perm.uid),&(buf->sem_perm.gid),&(buf->sem_perm.cuid),&(buf->sem_perm.cgid),&(buf->sem_perm.mode),&(buf->sem_nsems),&(buf->sem_otime),&(buf->sem_ctime));
  79   }
  80   else if (cmd==IPC_SET) {
  81     struct semid_ds *buf = va_arg(args,struct semid_ds*);
  82     ret = sem_set(id,buf->sem_perm.uid,buf->sem_perm.gid,buf->sem_perm.mode);
  83   }
  84   else if (cmd==IPC_RMID) ret = sem_destroy(id);
  85   else ret = -EINVAL;
  86   errno = ret<0?-ret:0;
  87   return ret<0?-1:0;
  88 }