ipc/shm_main_blk.c

   1 /***************************************************************************
   2  * Copyright 1995, Technion, Israel Institute of Technology
   3  * Electrical Eng, Software Lab.
   4  * Author:    Michael Veksler.
   5  ***************************************************************************
   6  * File:      shm_main_blk.c
   7  * Purpose:   Main Wine's shared memory block
   8  ***************************************************************************
   9  */
  10 #ifdef CONFIG_IPC
  11
  12 #define inline __inline__
  13 #include <sys/types.h>
  14 #include <sys/sem.h>
  15 #include <stdio.h>
  16 #include <time.h>
  17 #include <assert.h>
  18 #include <unistd.h>
  19 #include <errno.h>
  20 #include <signal.h>
  21 #include <stddebug.h>
  22 #include <debug.h>
  23 #include "shm_fragment.h"
  24 #include "shm_block.h"
  25 #include "shm_main_blk.h"
  26 #include "shm_semaph.h"
  27
  28 #define WineKey (   'W'+((int)'i'<<8)+((int)'n'<<16)+((int)'e'<<24)  )
  29 #define SHM_KEY_RANGE 8
  30
  31 /* main block (set during initialization) */
  32 struct shm_main_block *main_block=NULL;
  33 static char *shm_header="Wine - Windows emulator DDE mechanism";
  34 static int main_shm_id;
  35
  36 static void shm_main_refresh();
  37
  38 /* for debugging only */
  39 static void print_perm(struct ipc_perm *perm)
  40 {
  41   printf("Permission:\n");
  42   printf("\tKey=%d,   mode=%03o,   sequence #=%d\n",
  43          (int)perm->key,perm->mode, perm->seq);
  44   printf("\towner: uid=%d, gid=%d ;"  ,perm->uid, perm->gid);
  45   printf("  creator: uid=%d, gid=%d\n",perm->cuid,perm->cgid);
  46 }
  47
  48 /* for debugging only */
  49 /* print_shm_info: print shared memory descriptor info */
  50 static void print_shm_info(int shm_id)
  51 {
  52   struct shmid_ds ds;
  53   shmctl(shm_id, IPC_STAT, &ds );
  54
  55   printf("shm_id=%d, Size=0x%08x , Number of attaches=%d\n",
  56          shm_id, ds.shm_segsz, (int)ds.shm_nattch);
  57   if (ds.shm_atime)
  58      printf("Last attach=%s",ctime(&ds.shm_atime));
  59   if (ds.shm_dtime)
  60      printf("Last detach=%s",ctime(&ds.shm_dtime));
  61   printf("Last change=%s",ctime(&ds.shm_ctime));
  62   printf("pid: creator=%d, last operator=%d\n",
  63          (int)ds.shm_cpid,(int)ds.shm_lpid);
  64   print_perm( &ds.shm_perm);
  65
  66 }
  67
  68 int proc_exist(pid_t pid)
  69 {
  70   if ( kill(pid,0) == 0)           /* dummy signal to test existence */
  71      return 1;
  72   else if (errno==ESRCH)           /* "no such process" */
  73      return 0;
  74   else
  75      return 1;
  76 }
  77
  78 /* setup a new main shm block (only construct a shm block object). */
  79 static void shm_setup_main_block()
  80 {
  81   dprintf_shm(stddeb,"creating data structure\n");
  82   main_block->build_lock=1;
  83   strcpy(main_block->magic, shm_header);
  84
  85   shm_setup_block(&main_block->block,sizeof(*main_block),SHM_MINBLOCK);
  86
  87   dde_proc_init(main_block->proc);
  88   ATOM_GlobalInit();
  89   shm_sem_init(&main_block->sem);
  90
  91   /* main block set and data structure is stable now */
  92   main_block->build_lock=0;
  93 }
  94
  95 /* Delete everything related to main_block */
  96 void shm_delete_all(int shmid)
  97 {
  98   int proc_idx;
  99
 100   if (shmid == -1)
 101     shmid= main_shm_id;
 102
 103   shmctl( shmid, IPC_RMID, NULL);
 104
 105   for (proc_idx= 0 ; proc_idx < DDE_PROCS ; proc_idx++)
 106      dde_proc_done( &main_block->proc[proc_idx] );
 107
 108   shm_sem_done(&main_block->sem);
 109   shmdt( (void *) main_block);
 110   main_block= NULL;
 111 }
 112
 113 int DDE_no_of_attached()
 114 {
 115   struct shmid_ds shm_info;
 116
 117   if (shmctl(main_shm_id, IPC_STAT, &shm_info) == -1)
 118     return -1;
 119
 120   return shm_info.shm_nattch;
 121 }
 122 /*
 123 ** Test if shm_id is MainBlock and attach it (if it is),
 124 ** Return 1 if ok, 0 otherwise.
 125 */
 126 static int attach_MainBlock(int shm_id)
 127 {
 128   struct shmid_ds shm_info;
 129
 130   if (shmctl(shm_id, IPC_STAT, &shm_info) == -1)
 131      return 0;
 132
 133   /* Make sure we don't work on somebody else's block */
 134   if (shm_info.shm_perm.cuid != getuid()) { /* creator is not me */
 135      dprintf_shm(stddeb,"Creator is not me!\n");
 136      return 0;
 137   }
 138
 139   dprintf_shm(stddeb,"shared memory exist, attaching anywhere\n");
 140   main_block=(struct shm_main_block *)shmat(shm_id, 0, 0);
 141   if ( (int)main_block==-1) {
 142      dprintf_shm(stddeb,"Attach failed\n");
 143      return 0;
 144   }
 145
 146   if (strcmp(main_block->magic, shm_header) != 0) {
 147      dprintf_shm(stddeb,"Detaching, wrong magic\n");
 148      shmdt((void *)main_block);
 149      return 0;
 150   }
 151
 152   if (debugging_shm)
 153      print_shm_info(shm_id);
 154
 155   /* Is it an old unused block ? */
 156   if (shm_info.shm_nattch == 0) {
 157      dprintf_shm(stddeb,"No attaches, deleting old data\n");
 158      shm_delete_all(shm_id);
 159      return 0;
 160   }
 161
 162   /* Wait for data structure to stabilize */
 163   while (main_block->build_lock)
 164      usleep(10000);
 165
 166   main_shm_id= shm_id;
 167
 168   shm_main_refresh();
 169   return 1;
 170 }
 171
 172 /* (Function used by the constructor)
 173  * Try to get existing shared memory with key="Wine", size=SHM_MINBLOCK
 174  * complete user permission.
 175  * If such block is found - return true (1),  else return false (0)
 176  */
 177 static int shm_locate_MainBlock(key_t shm_key)
 178 {
 179     int shm_id;                 /* Descriptor to this shared memory */
 180     int i;
 181
 182     dprintf_shm(stddeb,"shm_locate_MainBlock: trying to attach, key=0x%x\n",
 183                 shm_key);
 184     for (i=0 ; i < SHM_KEY_RANGE ; i++) {
 185        dprintf_shm(stddeb,"iteration=%d\n", i);
 186
 187        shm_id= shmget ( shm_key+i, SHM_MINBLOCK ,0700);
 188
 189        if (shm_id != -1) {
 190          if ( attach_MainBlock(shm_id) ) {
 191            return 1;               /* success! */
 192          }
 193        } else {
 194           switch(errno) {
 195 #ifdef EIDRM
 196             case EIDRM:            /* segment destroyed */
 197 #endif
 198             case EACCES:           /* no user permision */
 199               break;
 200
 201             case ENOMEM:           /* no free memory */
 202             case ENOENT:           /* this key does not exist */
 203             default :
 204               dprintf_shm(stddeb,"shmget failed, errno=%d, %s\n",
 205                           errno, strerror(errno) );
 206               return 0;            /* Failed */
 207           }
 208        } /* if .. else */
 209     } /* for */
 210     return 0;
 211 }
 212
 213 /* (Function used by the constructor)
 214  * Try to allocate new shared memory with key="Wine", size=SHM_MINBLOCK
 215  * with complete user permission.
 216  * If allocation succeeds - return true (1),  else return false (0)
 217  */
 218 static int shm_create_MainBlock(key_t MainShmKey)
 219 {
 220   int shm_id;
 221   int flags= 0700 | IPC_CREAT | IPC_EXCL;
 222   int i;
 223
 224   dprintf_shm(stddeb,"creating shared memory\n");
 225
 226   /* try to allocate shared memory with key="Wine", size=SHM_MINBLOCK, */
 227   /* complete user permission */
 228   for (i=0 ; i < SHM_KEY_RANGE ; i++) {
 229      shm_id= shmget ( (key_t) MainShmKey, SHM_MINBLOCK, flags);
 230      if (shm_id != -1)
 231         break;
 232   }
 233   if (shm_id == -1) {
 234      dprintf_shm(stddeb,"failed to create shared memory\n");
 235      return 0;
 236   }
 237   dprintf_shm(stddeb,"shared memory created, attaching\n");
 238   main_block=(struct shm_main_block*) shmat(shm_id, 0,0);
 239   if (debugging_shm)
 240      print_shm_info(shm_id);
 241   main_shm_id= shm_id;
 242   shm_setup_main_block();
 243   dde_wnd_setup();
 244   return 1;
 245
 246 }
 247
 248 /* link to the dde shared memory block */
 249 /* RETURN: 0 on success, non zero on failure */
 250 int shm_init(void)
 251 {
 252   if ( !shm_locate_MainBlock(WineKey)
 253        && !shm_create_MainBlock(WineKey)) {
 254      fflush(stdout);
 255      fprintf(stderr,"shm_init: failed to init main shm block\n");
 256      exit(1);
 257   }
 258
 259   dde_proc_add(main_block->proc);
 260   return 0;
 261 }
 262
 263 static void shm_main_refresh()
 264 {
 265   int proc_idx;
 266
 267   for (proc_idx= 0 ; proc_idx < DDE_PROCS ; proc_idx++)
 268      dde_proc_refresh( &main_block->proc[proc_idx] );
 269 }
 270
 271 #endif  /* CONFIG_IPC */