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From wr...@apache.org
Subject cvs commit: apr/memory/unix apr_pools.c
Date Fri, 28 Sep 2001 15:22:35 GMT
wrowe       01/09/28 08:22:35

  Modified:    .        CHANGES
               include  apr_pools.h
               memory/unix apr_pools.c
  Log:
    Introduce apr_pool_lock for debugging, in combination with
    ALLOC_USE_MALLOC + DEBUG_WITH_MPROTECT.  Only implemented
    on Win32 today, very effective for debugging pool constness.
  
    Fixed a double-reservation for the union block_hdr size in the
    unix mprotect_alloc mmap() call.  I suspect the mmap can be
    modified to implement this on Unix, move the #define DO_LOCK()
    out of the win32 block if this is implemented.
  
  Revision  Changes    Path
  1.163     +5 -0      apr/CHANGES
  
  Index: CHANGES
  ===================================================================
  RCS file: /home/cvs/apr/CHANGES,v
  retrieving revision 1.162
  retrieving revision 1.163
  diff -u -r1.162 -r1.163
  --- CHANGES	2001/09/28 03:43:04	1.162
  +++ CHANGES	2001/09/28 15:22:34	1.163
  @@ -1,5 +1,10 @@
   Changes with APR b1  
   
  +  *) Introduce apr_pool_lock for debugging, in combination with
  +     ALLOC_USE_MALLOC + DEBUG_WITH_MPROTECT.  Only implemented
  +     on Win32 today, very effective for debugging pool constness.
  +     [William Rowe]
  +
     *) Optimize apr_pstrcat by caching lengths of first 6 strings
        [Brian Pane <bpane@pacbell.net>]
   
  
  
  
  1.61      +10 -0     apr/include/apr_pools.h
  
  Index: apr_pools.h
  ===================================================================
  RCS file: /home/cvs/apr/include/apr_pools.h,v
  retrieving revision 1.60
  retrieving revision 1.61
  diff -u -r1.60 -r1.61
  --- apr_pools.h	2001/09/28 14:05:23	1.60
  +++ apr_pools.h	2001/09/28 15:22:35	1.61
  @@ -291,6 +291,16 @@
                                              apr_pool_t *cont);
   
   /**
  + * Lock the pool. All the memory is write protected against changes.
  + * @param p The pool to lock
  + * @param writeprotect If true the pool's memory is locked read-only,
  + * otherwise the lock is released
  + * @remark This is a no-op if the program isn't built with appropriate flags
  + * on a platform that supports page locking.
  + */
  +APR_DECLARE(void) apr_pool_lock(apr_pool_t *p, int writeprotect);
  +
  +/**
    * Clear all memory in the pool and run all the cleanups. This also clears all
    * subpools.
    * @param p The pool to clear
  
  
  
  1.113     +84 -1     apr/memory/unix/apr_pools.c
  
  Index: apr_pools.c
  ===================================================================
  RCS file: /home/cvs/apr/memory/unix/apr_pools.c,v
  retrieving revision 1.112
  retrieving revision 1.113
  diff -u -r1.112 -r1.113
  --- apr_pools.c	2001/09/20 09:03:25	1.112
  +++ apr_pools.c	2001/09/28 15:22:35	1.113
  @@ -168,8 +168,10 @@
   #ifndef ALLOC_USE_MALLOC
   #error "ALLOC_USE_MALLOC must be enabled to use DEBUG_WITH_MPROTECT"
   #endif
  +#ifndef WIN32
   #include <sys/mman.h>
   #endif
  +#endif
   
   
   /** The memory allocation structure
  @@ -294,12 +296,15 @@
   
   #define SIZEOF_BLOCK(p) (((union block_hdr *)(p) - 1)->a.l)
   
  +#ifndef WIN32
  +
   static void *mprotect_malloc(apr_size_t size)
   {
       union block_hdr * addr;
   
       size += sizeof(union block_hdr);
  -    addr = mmap(NULL, size + sizeof(union block_hdr),
  +    
  +    addr = mmap(NULL, size,
                   PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS,
                   -1, 0);
       if (addr == MAP_FAILED)
  @@ -318,6 +323,64 @@
       }
   }
   
  +#else /* WIN32 */
  +
  +/* return the number insignificant bits in size, e.g. the typical page 
  + * size of 4096 on x86/WinNT will return 12, as the 12 low-order bits
  + * in the size aren't relevant to the number of pages.
  + */
  +static int mprotect_pageshift()
  +{
  +    static int savesize = 0;
  +    if (!savesize) {
  +        SYSTEM_INFO sysinfo;
  +        GetSystemInfo(&sysinfo);
  +        --sysinfo.dwPageSize;
  +        while (sysinfo.dwPageSize) {
  +            ++savesize;
  +            sysinfo.dwPageSize >>= 1;
  +        }
  +    }
  +    return savesize;
  +}
  +
  +static void *mprotect_malloc(apr_size_t size)
  +{
  +    union block_hdr * addr;
  +    int pageshift = mprotect_pageshift();
  +    size += sizeof(union block_hdr);
  +    size = (((size - 1) >> pageshift) + 1) << pageshift;
  +    addr = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
  +    if (!addr)
  +        return NULL;
  +    addr->a.l = size;
  +    return addr + 1;
  +}
  +
  +static void mprotect_free(void *addr)
  +{
  +    apr_size_t size = SIZEOF_BLOCK(addr);
  +    BOOL rv = VirtualFree((union block_hdr *)addr - 1, size, MEM_DECOMMIT);
  +    if (!rv) {
  +        fprintf(stderr, "could not protect. errno=%d\n", errno);
  +        abort();
  +    }
  +}
  +
  +static void mprotect_lock(void *addr, int lock)
  +{
  +    size_t size = SIZEOF_BLOCK(addr);
  +    DWORD prot = (lock ? PAGE_READONLY : PAGE_READWRITE);
  +    BOOL rv = VirtualProtect((union block_hdr *)addr - 1, size, prot, &prot);
  +    if (!rv) {
  +        fprintf(stderr, "could not protect. errno=%d\n", errno);
  +        abort();
  +    }
  +}
  +
  +#define DO_LOCK(p,l) mprotect_lock(p,l)
  +#endif
  +
   static void *mprotect_realloc(void *addr, apr_size_t size)
   {
       void *new_addr = mprotect_malloc(size);
  @@ -846,6 +909,26 @@
       alloc_mutex = NULL;
   #endif
       apr_pool_destroy(globalp);
  +}
  +
  +APR_DECLARE(void) apr_pool_lock(apr_pool_t *a, int l)
  +{
  +#ifdef ALLOC_USE_MALLOC
  +#ifdef DO_LOCK
  +    /* lock the subpools. */
  +    apr_pool_t *s;
  +    void *c, *n;
  +
  +    for (s = a->sub_pools; s; s = s->sub_next) {
  +	apr_pool_lock(s, l);
  +    }
  +
  +    for (c = a->allocation_list; c; c = n) {
  +	n = *(void **)c;
  +	DO_LOCK(c, l);
  +    }
  +#endif
  +#endif
   }
   
   /* We only want to lock the mutex if we are being called from apr_pool_clear.
  
  
  

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