make SHM header fixed-size

library/DFProcess-linux-SHM.cpp

@@ -452,7 +452,7 @@ void SHMProcess::read (const uint32_t offset, const uint32_t size, uint8_t *targ
     gcc_barrier
     ((shm_read *)d->my_shm)->pingpong = DFPP_READ;
     d->waitWhile(DFPP_READ);
-    memcpy (target, d->my_shm + sizeof(shm_ret_data),size);
+    memcpy (target, d->my_shm + SHM_HEADER,size);
 }
 
 uint8_t SHMProcess::readByte (const uint32_t offset)
@@ -544,7 +544,7 @@ void SHMProcess::write (uint32_t offset, uint32_t size, const uint8_t *source)
 {
     ((shm_write *)d->my_shm)->address = offset;
     ((shm_write *)d->my_shm)->length = size;
-    memcpy(d->my_shm+sizeof(shm_write),source, size);
+    memcpy(d->my_shm+SHM_HEADER,source, size);
     gcc_barrier
     ((shm_write *)d->my_shm)->pingpong = DFPP_WRITE;
     d->waitWhile(DFPP_WRITE);

library/shmserver/dfconnect.c

@@ -39,6 +39,7 @@ distribution.
 #include <time.h>
 #include <linux/futex.h>
 #include <sys/syscall.h>
+#include <signal.h>
 
 // a full memory barrier! better be safe than sorry.
 #define gcc_barrier asm volatile("" ::: "memory"); __sync_synchronize();
@@ -181,8 +182,8 @@ void SHM_Act (void)
             /*
         case DFPP_BOUNCE:
             length = ((shm_bounce *)shm)->length;
-            memcpy(BigFat,shm + sizeof(shm_bounce),length);
+            memcpy(BigFat,shm + SHM_HEADER,length);
-            memcpy(shm + sizeof(shm_ret_data),BigFat,length);
+            memcpy(shm + SHM_HEADER,BigFat,length);
             ((shm_cmd *)shm)->pingpong = DFPP_RET_DATA;
             goto check_again;
             */
@@ -201,7 +202,7 @@ void SHM_Act (void)
         case DFPP_READ:
             length = ((shm_read *)shm)->length;
             address = ((shm_read *)shm)->address;
-            memcpy(shm + sizeof(shm_ret_data), (void *) address,length);
+            memcpy(shm + SHM_HEADER, (void *) address,length);
             gcc_barrier
             ((shm_cmd *)shm)->pingpong = DFPP_RET_DATA;
             goto check_again;
@@ -230,7 +231,7 @@ void SHM_Act (void)
         case DFPP_WRITE:
             address = ((shm_write *)shm)->address;
             length = ((shm_write *)shm)->length;
-            memcpy((void *)address, shm + sizeof(shm_write),length);
+            memcpy((void *)address, shm + SHM_HEADER,length);
             gcc_barrier
             ((shm_cmd *)shm)->pingpong = DFPP_SUSPENDED;
             goto check_again;

library/shmserver/dfconnect.h

@@ -3,7 +3,9 @@
 
 #define PINGPONG_VERSION 1
 #define SHM_KEY 123466
-#define SHM_SIZE 1024*1024
+#define SHM_HEADER 1024
+#define SHM_BODY 1024*1024
+#define SHM_SIZE SHM_HEADER+SHM_BODY
 
 /*
     * read - parameters are address and length