1 /* Copyright (c) 2014. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
9 #include "mc_private.h"
11 #include "mc_page_store.h"
13 mc_mem_region_t mc_get_snapshot_region(void* addr, mc_snapshot_t snapshot)
15 for (size_t i = 0; i != NB_REGIONS; ++i) {
16 mc_mem_region_t region = snapshot->regions[i];
17 void* start = region->start_addr;
18 void* end = (char*) start + region->size;
20 if (addr >= start && addr < end) {
28 /** @brief Read memory from a snapshot region broken across fragmented pages
30 * @param addr Process (non-snapshot) address of the data
31 * @param region Snapshot memory region where the data is located
32 * @param target Buffer to store the value
33 * @param size Size of the data to read in bytes
34 * @return Pointer where the data is located (target buffer of original location)
36 void* mc_snapshot_read_fragmented(void* addr, mc_mem_region_t region, void* target, size_t size)
38 void* end = (char*) addr + size - 1;
39 size_t page_end = mc_page_number(NULL, end);
43 xbt_die("Missing destination buffer for fragmented memory access");
47 while (mc_page_number(NULL, addr) != page_end) {
48 void* snapshot_addr = mc_translate_address_region((uintptr_t) addr, region);
49 void* next_page = mc_page_from_number(NULL, mc_page_number(NULL, addr) + 1);
50 size_t readable = (char*) next_page - (char*) addr;
51 memcpy(dest, snapshot_addr, readable);
52 addr = (char*) addr + readable;
53 dest = (char*) dest + readable;
58 void* snapshot_addr = mc_translate_address_region((uintptr_t)addr, region);
59 memcpy(dest, snapshot_addr, size);
64 /** @brief Read memory from a snapshot
66 * @param addr Process (non-snapshot) address of the data
67 * @param snapshot Snapshot (or NULL is no snapshot)
68 * @param target Buffer to store the value
69 * @param size Size of the data to read in bytes
70 * @return Pointer where the data is located (target buffer of original location)
72 void* mc_snapshot_read(void* addr, mc_snapshot_t snapshot, void* target, size_t size)
75 mc_mem_region_t region = mc_get_snapshot_region(addr, snapshot);
76 return mc_snapshot_read_region(addr, region, target, size);
82 /** Compare memory between snapshots (with known regions)
84 * @param addr1 Address in the first snapshot
85 * @param snapshot2 Region of the address in the first snapshot
86 * @param addr2 Address in the second snapshot
87 * @param snapshot2 Region of the address in the second snapshot
88 * @return same as memcmp
90 int mc_snapshot_region_memcmp(
91 void* addr1, mc_mem_region_t region1,
92 void* addr2, mc_mem_region_t region2, size_t size)
94 // Using alloca() for large allocations may trigger stack overflow:
95 // use malloc if the buffer is too big.
96 bool stack_alloc = size < 64;
97 void* buffer1a = region1->data ? NULL : stack_alloc ? alloca(size) : malloc(size);
98 void* buffer2a = region2->data ? NULL : stack_alloc ? alloca(size) : malloc(size);
99 void* buffer1 = mc_snapshot_read_region(addr1, region1, buffer1a, size);
100 void* buffer2 = mc_snapshot_read_region(addr2, region2, buffer2a, size);
102 if (buffer1 == buffer2) {
105 res = memcmp(buffer1, buffer2, size);
114 /** Compare memory between snapshots
116 * @param addr1 Address in the first snapshot
117 * @param snapshot1 First snapshot
118 * @param addr2 Address in the second snapshot
119 * @param snapshot2 Second snapshot
120 * @return same as memcmp
122 int mc_snapshot_memcp(
123 void* addr1, mc_snapshot_t snapshot1,
124 void* addr2, mc_snapshot_t snapshot2, size_t size)
126 mc_mem_region_t region1 = mc_get_snapshot_region(addr1, snapshot1);
127 mc_mem_region_t region2 = mc_get_snapshot_region(addr2, snapshot2);
128 return mc_snapshot_region_memcmp(addr1, region1, addr2, region2, size);