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