使用valgrind检测Android native程序的内存

下载http://valgrind.org/downloads/valgrind-3.7.0.tar.bz2，使用ndk toolchain，按照代码中的README.android编译Android版本的valgrind，push到/data分区，这里笔者push到了/data/local/valgrind/，同时把VALGRIND_LIB 环境变量设置为/data/local/valgrind/lib/valgrind

编写一个有很多内存错误的程序：

main(){        {                   int x;                printf ("x = %d\n", x);         }           {                   char* arr  = malloc(10);                int*  arr2 = malloc(sizeof(int));                write( 1 /* stdout */, arr, 10 );        }           {                   char a[100];                memcpy(a, a + 20, 40);        }           {                   char *q;                 q = malloc(1024*1024);                q[1] = 1024;        }           {                   char *p;                 p = malloc(1024*1024);                p[0] = p[0];                p[1] = 1024;                free(p);                free(p);        }   }

使用valgrind运行之：

/data/local/valgrind/bin/valgrind --leak-check=full --track-origins=yes  /data/check

得到如下结果：

==965== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.==965== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info==965== Command: /data/check==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD1AF6A: vfprintf (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD1B3FA: vfprintf (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD1B3FE: vfprintf (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD1B478: vfprintf (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD1B47E: vfprintf (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD0FE00: __udivdi3 (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD0D230: __udivsi3 (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD0D294: __udivsi3 (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD0FE5C: __udivdi3 (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Conditional jump or move depends on uninitialised value(s)==965==    at 0xAFD0FEAC: __udivdi3 (in /system/lib/libc.so)==965==  Uninitialised value was created by a stack allocation==965==    at 0x83D8: main (check.c:2)==965== ==965== Syscall param write(buf) points to uninitialised byte(s)==965==    at 0xAFD0B47C: write (in /system/lib/libc.so)==965==  Address 0x480a058 is 0 bytes inside a block of size 10 alloc'd==965==    at 0x80103318: malloc (vg_replace_malloc.c:263)==965==    by 0x83F7: main (check.c:8)==965==  Uninitialised value was created by a heap allocation==965==    at 0x80103318: malloc (vg_replace_malloc.c:263)==965==    by 0x83F7: main (check.c:8)==965== ==965== Source and destination overlap in memcpy(0xbde6b908, 0xbde6b91c, 40)==965==    at 0x80106A64: memcpy (mc_replace_strmem.c:838)==965==    by 0x843B: main (check.c:14)==965== ==965== Invalid free() / delete / delete[] / realloc()==965==    at 0x80102E1C: free (vg_replace_malloc.c:427)==965==    by 0x849B: main (check.c:30)==965==  Address 0x490a100 is 0 bytes inside a block of size 1,048,576 free'd==965==    at 0x80102E1C: free (vg_replace_malloc.c:427)==965==    by 0x8493: main (check.c:29)==965== ==965== ==965== HEAP SUMMARY:==965==     in use at exit: 1,052,686 bytes in 4 blocks==965==   total heap usage: 5 allocs, 2 frees, 2,101,262 bytes allocated==965== ==965== 4 bytes in 1 blocks are definitely lost in loss record 1 of 4==965==    at 0x80103318: malloc (vg_replace_malloc.c:263)==965==    by 0x8407: main (check.c:9)==965== ==965== 10 bytes in 1 blocks are definitely lost in loss record 2 of 4==965==    at 0x80103318: malloc (vg_replace_malloc.c:263)==965==    by 0x83F7: main (check.c:8)==965== ==965== 1,048,576 bytes in 1 blocks are definitely lost in loss record 4 of 4==965==    at 0x80103318: malloc (vg_replace_malloc.c:263)==965==    by 0x8443: main (check.c:18)==965== ==965== LEAK SUMMARY:==965==    definitely lost: 1,048,590 bytes in 3 blocks==965==    indirectly lost: 0 bytes in 0 blocks==965==      possibly lost: 0 bytes in 0 blocks==965==    still reachable: 4,096 bytes in 1 blocks==965==         suppressed: 0 bytes in 0 blocks==965== Reachable blocks (those to which a pointer was found) are not shown.==965== To see them, rerun with: --leak-check=full --show-reachable=yes==965== ==965== For counts of detected and suppressed errors, rerun with: -v==965== ERROR SUMMARY: 275 errors from 16 contexts (suppressed: 0 from 0)

这些错误可以分为如下几类：

1. Illegal read / Illegal write errors
2. Use of uninitialised values
3. Use of uninitialised or unaddressable values in system calls
4. Illegal frees
5. When a heap block is freed with an inappropriate deallocation function
6. Overlapping source and destination blocks
7. Memory leak detection