Valgrind 安装
1、 到www.valgrind.org下载最新版valgrind-3.7.0.tar.bz2 2、 解压安装包:tar –jxvf valgrind-3.7.0.tar.bz2 3、 解压后生成目录valgrind-3.7.0 4、 cd valgrind-3.7.0 5、 ./configure 6、 Make; 7、 sudo make install
具体请参看解压后的目录valgrind-3.7.0下的README文件。
Valgrind 使用
用法: valgrind [options] prog-and-args [options]: 常用选项,适用于所有Valgrind工具
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-tool=<name> 最常用的选项。运行 valgrind中名为toolname的工具。默认memcheck。
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h –help 显示帮助信息。
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-version 显示valgrind内核的版本,每个工具都有各自的版本。
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q –quiet 安静地运行,只打印错误信息。
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v –verbose 更详细的信息, 增加错误数统计。
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-trace-children=no|yes 跟踪子线程? [no]
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-track-fds=no|yes 跟踪打开的文件描述?[no]
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-time-stamp=no|yes 增加时间戳到LOG信息? [no]
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-log-fd=<number> 输出LOG到描述符文件 [2=stderr]
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-log-file=<file> 将输出的信息写入到filename.PID的文件里,PID是运行程序的进行ID
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-log-file-exactly=<file> 输出LOG信息到 file
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-log-file-qualifier=<VAR> 取得环境变量的值来做为输出信息的文件名。 [none]
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-log-socket=ipaddr:port 输出LOG到socket ,ipaddr:port
LOG信息输出
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-xml=yes 将信息以xml格式输出,只有memcheck可用
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-num-callers=<number> show <number> callers in stack traces [12]
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-error-limit=no|yes 如果太多错误,则停止显示新错误? [yes]
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-error-exitcode=<number> 如果发现错误则返回错误代码 [0=disable]
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-db-attach=no|yes 当出现错误,valgrind会自动启动调试器gdb。[no]
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-db-command=<command> 启动调试器的命令行选项[gdb -nw %f %p]
适用于Memcheck工具的相关选项:
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-leak-check=no|summary|full 要求对leak给出详细信息? [summary]
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-leak-resolution=low|med|high how much bt merging in leak check [low]
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-show-reachable=no|yes show reachable blocks in leak check? [no]
Valgrind 使用举例
下面是一段有问题的C程序代码test.c
#include <stdlib.h> void f(void) { int* x = malloc(10 * sizeof(int)); x[10] = 0; //问题1: 数组下标越界 } //问题2: 内存没有释放
int main(void) { f(); return 0; }
1、 编译程序test.c gcc -Wall test.c -g -o test 2、 使用Valgrind检查程序BUG valgrind --tool=memcheck --leak-check=full ./test 3、 分析输出的调试信息 ==3908== Memcheck, a memory error detector. ==3908== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al. ==3908== Using LibVEX rev 1732, a library for dynamic binary translation. ==3908== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP. ==3908== Using valgrind-3.2.3, a dynamic binary instrumentation framework. ==3908== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al. ==3908== For more details, rerun with: -v ==3908== --3908-- DWARF2 CFI reader: unhandled CFI instruction 0:50 --3908-- DWARF2 CFI reader: unhandled CFI instruction 0:50 /*数组越界错误*/ ==3908== Invalid write of size 4 ==3908== at 0x8048384: f (test.c:6) ==3908== by 0x80483AC: main (test.c:11) ==3908== Address 0x400C050 is 0 bytes after a block of size 40 alloc'd ==3908== at 0x40046F2: malloc (vg_replace_malloc.c:149) ==3908== by 0x8048377: f (test.c:5) ==3908== by 0x80483AC: main (test.c:11) ==3908== ==3908== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 14 from 1) ==3908== malloc/free: in use at exit: 40 bytes in 1 blocks. ==3908== malloc/free: 1 allocs, 0 frees, 40 bytes allocated. ==3908== For counts of detected errors, rerun with: -v ==3908== searching for pointers to 1 not-freed blocks. ==3908== checked 59,124 bytes. ==3908== ==3908== /*有内存空间没有释放*/ ==3908== 40 bytes in 1 blocks are definitely lost in loss record 1 of 1 ==3908== at 0x40046F2: malloc (vg_replace_malloc.c:149) ==3908== by 0x8048377: f (test.c:5) ==3908== by 0x80483AC: main (test.c:11) ==3908== ==3908== LEAK SUMMARY: ==3908== definitely lost: 40 bytes in 1 blocks. ==3908== possibly lost: 0 bytes in 0 blocks. ==3908== still reachable: 0 bytes in 0 blocks. ==3908== suppressed: 0 bytes in 0 blocks.