/**
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* \file
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* Support for mapping code into the process address space
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*
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* Author:
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* Mono Team (mono-list@lists.ximian.com)
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*
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* Copyright 2001-2008 Novell, Inc.
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* Licensed under the MIT license. See LICENSE file in the project root for full license information.
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*/
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#include <config.h>
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#ifndef HOST_WIN32
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#include <sys/types.h>
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#if HAVE_SYS_STAT_H
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#include <sys/stat.h>
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#endif
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#if HAVE_SYS_MMAN_H
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#include <sys/mman.h>
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#endif
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#ifdef HAVE_SIGNAL_H
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#include <signal.h>
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#endif
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <errno.h>
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#endif /* !HOST_WIN32 */
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#include "mono-mmap.h"
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#include "mono-mmap-internals.h"
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#include "mono-proclib.h"
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#include <mono/utils/mono-threads.h>
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#include <mono/utils/atomic.h>
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#include <mono/utils/mono-counters.h>
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#define BEGIN_CRITICAL_SECTION do { \
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MonoThreadInfo *__info = mono_thread_info_current_unchecked (); \
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if (__info) __info->inside_critical_region = TRUE; \
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#define END_CRITICAL_SECTION \
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if (__info) __info->inside_critical_region = FALSE; \
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} while (0) \
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#ifndef MAP_ANONYMOUS
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#define MAP_ANONYMOUS MAP_ANON
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#endif
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#ifndef MAP_32BIT
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#define MAP_32BIT 0
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#endif
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typedef struct {
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int size;
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int pid;
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int reserved;
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short stats_start;
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short stats_end;
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} SAreaHeader;
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void*
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malloc_shared_area (int pid)
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{
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int size = mono_pagesize ();
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SAreaHeader *sarea = (SAreaHeader *) g_malloc0 (size);
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sarea->size = size;
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sarea->pid = pid;
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sarea->stats_start = sizeof (SAreaHeader);
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sarea->stats_end = sizeof (SAreaHeader);
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return sarea;
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}
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char*
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aligned_address (char *mem, size_t size, size_t alignment)
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{
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char *aligned = (char*)((size_t)(mem + (alignment - 1)) & ~(alignment - 1));
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g_assert (aligned >= mem && aligned + size <= mem + size + alignment && !((size_t)aligned & (alignment - 1)));
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return aligned;
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}
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static size_t allocation_count [MONO_MEM_ACCOUNT_MAX];
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static size_t total_allocation_count;
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static size_t alloc_limit;
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void
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account_mem (MonoMemAccountType type, ssize_t size)
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{
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mono_atomic_fetch_add_word (&allocation_count [type], size);
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mono_atomic_fetch_add_word (&total_allocation_count, size);
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}
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void
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mono_valloc_set_limit (size_t size)
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{
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alloc_limit = size;
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}
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gboolean
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mono_valloc_can_alloc (size_t size)
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{
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if (alloc_limit)
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return (total_allocation_count + size) < alloc_limit;
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return TRUE;
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}
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const char*
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mono_mem_account_type_name (MonoMemAccountType type)
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{
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static const char *names[] = {
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"code",
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"hazard pointers",
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"domain",
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"SGen internal",
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"SGen nursery",
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"SGen LOS",
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"SGen mark&sweep",
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"SGen card table",
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"SGen shadow card table",
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"SGen debugging",
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"SGen binary protocol",
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"exceptions",
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"profiler",
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"other"
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};
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return names [type];
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}
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void
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mono_mem_account_register_counters (void)
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{
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for (int i = 0; i < MONO_MEM_ACCOUNT_MAX; ++i) {
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const char *prefix = "Valloc ";
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const char *name = mono_mem_account_type_name (i);
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char descr [128];
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g_assert (strlen (prefix) + strlen (name) < sizeof (descr));
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sprintf (descr, "%s%s", prefix, name);
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mono_counters_register (descr, MONO_COUNTER_WORD | MONO_COUNTER_RUNTIME | MONO_COUNTER_BYTES | MONO_COUNTER_VARIABLE, (void*)&allocation_count [i]);
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}
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}
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#ifdef HOST_WIN32
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// Windows specific implementation in mono-mmap-windows.c
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#define HAVE_VALLOC_ALIGNED
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#else
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static void* malloced_shared_area = NULL;
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#if defined(HAVE_MMAP)
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/**
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* mono_pagesize:
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* Get the page size in use on the system. Addresses and sizes in the
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* mono_mmap(), mono_munmap() and mono_mprotect() calls must be pagesize
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* aligned.
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*
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* Returns: the page size in bytes.
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*/
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int
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mono_pagesize (void)
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{
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static int saved_pagesize = 0;
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if (saved_pagesize)
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return saved_pagesize;
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// Prefer sysconf () as it's signal safe.
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#if defined (HAVE_SYSCONF) && defined (_SC_PAGESIZE)
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saved_pagesize = sysconf (_SC_PAGESIZE);
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#else
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saved_pagesize = getpagesize ();
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#endif
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return saved_pagesize;
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}
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int
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mono_valloc_granule (void)
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{
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return mono_pagesize ();
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}
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static int
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prot_from_flags (int flags)
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{
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int prot = PROT_NONE;
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/* translate the protection bits */
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if (flags & MONO_MMAP_READ)
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prot |= PROT_READ;
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if (flags & MONO_MMAP_WRITE)
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prot |= PROT_WRITE;
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if (flags & MONO_MMAP_EXEC)
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prot |= PROT_EXEC;
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return prot;
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}
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/**
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* mono_valloc:
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* \param addr memory address
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* \param length memory area size
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* \param flags protection flags
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* Allocates \p length bytes of virtual memory with the \p flags
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* protection. \p addr can be a preferred memory address or a
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* mandatory one if MONO_MMAP_FIXED is set in \p flags.
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* \p addr must be pagesize aligned and can be NULL.
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* \p length must be a multiple of pagesize.
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* \returns NULL on failure, the address of the memory area otherwise
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*/
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void*
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mono_valloc (void *addr, size_t length, int flags, MonoMemAccountType type)
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{
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void *ptr;
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int mflags = 0;
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int prot = prot_from_flags (flags);
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if (!mono_valloc_can_alloc (length))
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return NULL;
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/* translate the flags */
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if (flags & MONO_MMAP_FIXED)
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mflags |= MAP_FIXED;
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if (flags & MONO_MMAP_32BIT)
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mflags |= MAP_32BIT;
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mflags |= MAP_ANONYMOUS;
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mflags |= MAP_PRIVATE;
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BEGIN_CRITICAL_SECTION;
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ptr = mmap (addr, length, prot, mflags, -1, 0);
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if (ptr == MAP_FAILED) {
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int fd = open ("/dev/zero", O_RDONLY);
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if (fd != -1) {
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ptr = mmap (addr, length, prot, mflags, fd, 0);
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close (fd);
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}
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}
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END_CRITICAL_SECTION;
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if (ptr == MAP_FAILED)
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return NULL;
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account_mem (type, (ssize_t)length);
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return ptr;
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}
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/**
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* mono_vfree:
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* \param addr memory address returned by mono_valloc ()
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* \param length size of memory area
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* Remove the memory mapping at the address \p addr.
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* \returns \c 0 on success.
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*/
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int
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mono_vfree (void *addr, size_t length, MonoMemAccountType type)
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{
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int res;
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BEGIN_CRITICAL_SECTION;
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res = munmap (addr, length);
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END_CRITICAL_SECTION;
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account_mem (type, -(ssize_t)length);
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return res;
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}
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/**
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* mono_file_map:
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* \param length size of data to map
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* \param flags protection flags
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* \param fd file descriptor
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* \param offset offset in the file
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* \param ret_handle pointer to storage for returning a handle for the map
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* Map the area of the file pointed to by the file descriptor \p fd, at offset
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* \p offset and of size \p length in memory according to the protection flags
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* \p flags.
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* \p offset and \p length must be multiples of the page size.
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* \p ret_handle must point to a void*: this value must be used when unmapping
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* the memory area using \c mono_file_unmap().
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*/
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extern MonoFileMapMap file_map_func;
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extern MonoFileMapUnmap file_unmap_func;
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void*
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mono_file_map (size_t length, int flags, int fd, guint64 offset, void **ret_handle)
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{
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void *ptr;
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if (file_map_func)
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{
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BEGIN_CRITICAL_SECTION;
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ptr = file_map_func(length, flags, fd, offset, ret_handle);
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END_CRITICAL_SECTION;
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return ptr;
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}
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int mflags = 0;
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int prot = prot_from_flags (flags);
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/* translate the flags */
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if (flags & MONO_MMAP_PRIVATE)
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mflags |= MAP_PRIVATE;
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if (flags & MONO_MMAP_SHARED)
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mflags |= MAP_SHARED;
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if (flags & MONO_MMAP_FIXED)
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mflags |= MAP_FIXED;
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if (flags & MONO_MMAP_32BIT)
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mflags |= MAP_32BIT;
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BEGIN_CRITICAL_SECTION;
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ptr = mmap (0, length, prot, mflags, fd, offset);
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END_CRITICAL_SECTION;
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if (ptr == MAP_FAILED)
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return NULL;
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*ret_handle = (void*)length;
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return ptr;
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}
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/**
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* mono_file_unmap:
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* \param addr memory address returned by mono_file_map ()
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* \param handle handle of memory map
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* Remove the memory mapping at the address \p addr.
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* \p handle must be the value returned in ret_handle by \c mono_file_map().
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* \returns \c 0 on success.
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*/
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int
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mono_file_unmap (void *addr, void *handle)
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{
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int res;
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BEGIN_CRITICAL_SECTION;
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if (file_unmap_func)
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res = file_unmap_func(addr, handle);
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else
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res = munmap(addr, (size_t)handle);
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END_CRITICAL_SECTION;
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return res;
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}
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/**
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* mono_mprotect:
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* \param addr memory address
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* \param length size of memory area
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* \param flags new protection flags
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* Change the protection for the memory area at \p addr for \p length bytes
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* to matche the supplied \p flags.
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* If \p flags includes MON_MMAP_DISCARD the pages are discarded from memory
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* and the area is cleared to zero.
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* \p addr must be aligned to the page size.
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* \p length must be a multiple of the page size.
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* \returns \c 0 on success.
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*/
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int
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mono_mprotect (void *addr, size_t length, int flags)
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{
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int prot = prot_from_flags (flags);
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if (flags & MONO_MMAP_DISCARD) {
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/* on non-linux the pages are not guaranteed to be zeroed (*bsd, osx at least) */
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#ifdef __linux__
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if (madvise (addr, length, MADV_DONTNEED))
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memset (addr, 0, length);
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#else
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memset (addr, 0, length);
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#ifdef HAVE_MADVISE
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madvise (addr, length, MADV_DONTNEED);
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madvise (addr, length, MADV_FREE);
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#else
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posix_madvise (addr, length, POSIX_MADV_DONTNEED);
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#endif
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#endif
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}
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return mprotect (addr, length, prot);
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}
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#else
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/* dummy malloc-based implementation */
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int
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mono_pagesize (void)
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{
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return 4096;
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}
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int
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mono_valloc_granule (void)
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{
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return mono_pagesize ();
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}
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void*
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mono_valloc (void *addr, size_t length, int flags, MonoMemAccountType type)
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{
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g_assert (addr == NULL);
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return mono_valloc_aligned (length, mono_pagesize (), flags, type);
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}
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void*
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mono_valloc_aligned (size_t size, size_t alignment, int flags, MonoMemAccountType type)
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{
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void *res = NULL;
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if (posix_memalign (&res, alignment, size))
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return NULL;
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memset (res, 0, size);
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return res;
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}
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#define HAVE_VALLOC_ALIGNED
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int
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mono_vfree (void *addr, size_t length, MonoMemAccountType type)
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{
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g_free (addr);
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return 0;
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}
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int
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mono_mprotect (void *addr, size_t length, int flags)
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{
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if (flags & MONO_MMAP_DISCARD) {
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memset (addr, 0, length);
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}
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return 0;
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}
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#endif // HAVE_MMAP
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#if defined(HAVE_SHM_OPEN) && !defined (DISABLE_SHARED_PERFCOUNTERS)
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static int use_shared_area;
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static gboolean
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shared_area_disabled (void)
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{
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if (!use_shared_area) {
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if (g_hasenv ("MONO_DISABLE_SHARED_AREA"))
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use_shared_area = -1;
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else
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use_shared_area = 1;
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}
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return use_shared_area == -1;
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}
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static int
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mono_shared_area_instances_slow (void **array, int count, gboolean cleanup)
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{
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int i, j = 0;
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int num;
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void *data;
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gpointer *processes = mono_process_list (&num);
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for (i = 0; i < num; ++i) {
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data = mono_shared_area_for_pid (processes [i]);
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if (!data)
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continue;
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mono_shared_area_unload (data);
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if (!cleanup) {
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if (j < count)
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array [j++] = processes [i];
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else
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break;
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}
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}
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g_free (processes);
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return j;
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}
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static int
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mono_shared_area_instances_helper (void **array, int count, gboolean cleanup)
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{
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const char *name;
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int i = 0;
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int curpid = getpid ();
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GDir *dir = g_dir_open ("/dev/shm/", 0, NULL);
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if (!dir)
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return mono_shared_area_instances_slow (array, count, cleanup);
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while ((name = g_dir_read_name (dir))) {
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int pid;
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char *nend;
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if (strncmp (name, "mono.", 5))
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continue;
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pid = strtol (name + 5, &nend, 10);
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if (pid <= 0 || nend == name + 5 || *nend)
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continue;
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if (!cleanup) {
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if (i < count)
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array [i++] = GINT_TO_POINTER (pid);
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else
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break;
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}
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if (curpid != pid && kill (pid, 0) == -1 && (errno == ESRCH || errno == ENOMEM)) {
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char buf [128];
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g_snprintf (buf, sizeof (buf), "/mono.%d", pid);
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shm_unlink (buf);
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}
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}
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g_dir_close (dir);
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return i;
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}
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void*
|
mono_shared_area (void)
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{
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int fd;
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int pid = getpid ();
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/* we should allow the user to configure the size */
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int size = mono_pagesize ();
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char buf [128];
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void *res;
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SAreaHeader *header;
|
|
if (shared_area_disabled ()) {
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if (!malloced_shared_area)
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malloced_shared_area = malloc_shared_area (0);
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/* get the pid here */
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return malloced_shared_area;
|
}
|
|
/* perform cleanup of segments left over from dead processes */
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mono_shared_area_instances_helper (NULL, 0, TRUE);
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g_snprintf (buf, sizeof (buf), "/mono.%d", pid);
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fd = shm_open (buf, O_CREAT|O_EXCL|O_RDWR, S_IRUSR|S_IWUSR|S_IRGRP);
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if (fd == -1 && errno == EEXIST) {
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/* leftover */
|
shm_unlink (buf);
|
fd = shm_open (buf, O_CREAT|O_EXCL|O_RDWR, S_IRUSR|S_IWUSR|S_IRGRP);
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}
|
/* in case of failure we try to return a memory area anyway,
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* even if it means the data can't be read by other processes
|
*/
|
if (fd == -1)
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return malloc_shared_area (pid);
|
if (ftruncate (fd, size) != 0) {
|
shm_unlink (buf);
|
close (fd);
|
}
|
BEGIN_CRITICAL_SECTION;
|
res = mmap (NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
|
END_CRITICAL_SECTION;
|
|
if (res == MAP_FAILED) {
|
shm_unlink (buf);
|
close (fd);
|
return malloc_shared_area (pid);
|
}
|
/* we don't need the file descriptor anymore */
|
close (fd);
|
header = (SAreaHeader *) res;
|
header->size = size;
|
header->pid = pid;
|
header->stats_start = sizeof (SAreaHeader);
|
header->stats_end = sizeof (SAreaHeader);
|
|
mono_atexit (mono_shared_area_remove);
|
return res;
|
}
|
|
void
|
mono_shared_area_remove (void)
|
{
|
char buf [128];
|
|
if (shared_area_disabled ()) {
|
if (malloced_shared_area)
|
g_free (malloced_shared_area);
|
return;
|
}
|
|
g_snprintf (buf, sizeof (buf), "/mono.%d", getpid ());
|
shm_unlink (buf);
|
if (malloced_shared_area)
|
g_free (malloced_shared_area);
|
}
|
|
void*
|
mono_shared_area_for_pid (void *pid)
|
{
|
int fd;
|
/* we should allow the user to configure the size */
|
int size = mono_pagesize ();
|
char buf [128];
|
void *res;
|
|
if (shared_area_disabled ())
|
return NULL;
|
|
g_snprintf (buf, sizeof (buf), "/mono.%d", GPOINTER_TO_INT (pid));
|
|
fd = shm_open (buf, O_RDONLY, S_IRUSR|S_IRGRP);
|
if (fd == -1)
|
return NULL;
|
BEGIN_CRITICAL_SECTION;
|
res = mmap (NULL, size, PROT_READ, MAP_SHARED, fd, 0);
|
END_CRITICAL_SECTION;
|
|
if (res == MAP_FAILED) {
|
close (fd);
|
return NULL;
|
}
|
/* FIXME: validate the area */
|
/* we don't need the file descriptor anymore */
|
close (fd);
|
return res;
|
}
|
|
void
|
mono_shared_area_unload (void *area)
|
{
|
/* FIXME: currently we load only a page */
|
BEGIN_CRITICAL_SECTION;
|
munmap (area, mono_pagesize ());
|
END_CRITICAL_SECTION;
|
}
|
|
int
|
mono_shared_area_instances (void **array, int count)
|
{
|
return mono_shared_area_instances_helper (array, count, FALSE);
|
}
|
#else
|
void*
|
mono_shared_area (void)
|
{
|
if (!malloced_shared_area)
|
malloced_shared_area = malloc_shared_area (getpid ());
|
/* get the pid here */
|
return malloced_shared_area;
|
}
|
|
void
|
mono_shared_area_remove (void)
|
{
|
if (malloced_shared_area)
|
g_free (malloced_shared_area);
|
malloced_shared_area = NULL;
|
}
|
|
void*
|
mono_shared_area_for_pid (void *pid)
|
{
|
return NULL;
|
}
|
|
void
|
mono_shared_area_unload (void *area)
|
{
|
}
|
|
int
|
mono_shared_area_instances (void **array, int count)
|
{
|
return 0;
|
}
|
|
#endif // HAVE_SHM_OPEN
|
|
#endif // HOST_WIN32
|
|
#ifndef HAVE_VALLOC_ALIGNED
|
void*
|
mono_valloc_aligned (size_t size, size_t alignment, int flags, MonoMemAccountType type)
|
{
|
/* Allocate twice the memory to be able to put the block on an aligned address */
|
char *mem = (char *) mono_valloc (NULL, size + alignment, flags, type);
|
char *aligned;
|
|
if (!mem)
|
return NULL;
|
|
aligned = aligned_address (mem, size, alignment);
|
|
if (aligned > mem)
|
mono_vfree (mem, aligned - mem, type);
|
if (aligned + size < mem + size + alignment)
|
mono_vfree (aligned + size, (mem + size + alignment) - (aligned + size), type);
|
|
return aligned;
|
}
|
#endif
|
|
int
|
mono_pages_not_faulted (void *addr, size_t size)
|
{
|
#ifdef HAVE_MINCORE
|
int i;
|
gint64 count;
|
int pagesize = mono_pagesize ();
|
int npages = (size + pagesize - 1) / pagesize;
|
char *faulted = (char *) g_malloc0 (sizeof (char*) * npages);
|
|
/*
|
* We cast `faulted` to void* because Linux wants an unsigned
|
* char* while BSD wants a char*.
|
*/
|
#ifdef __linux__
|
if (mincore (addr, size, (unsigned char *)faulted) != 0) {
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#else
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if (mincore (addr, size, (char *)faulted) != 0) {
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#endif
|
count = -1;
|
} else {
|
count = 0;
|
for (i = 0; i < npages; ++i) {
|
if (faulted [i] != 0)
|
++count;
|
}
|
}
|
|
g_free (faulted);
|
|
return count;
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#else
|
return -1;
|
#endif
|
}
|
