linux /proc/<pid>/exe & valgrind

Question

根据手册页 /proc/pid/exe 是一个符号链接，其中包含已执行命令的实际路径..

当我在我的程序上运行 valgrind 时，我看到 /proc/pid/exe 指向 /usr/lib64/valgrind/amd64-linux/memcheck p>

lnx-host> which valgrind
/usr/bin/valgrind

知道为什么 /proc/pid/exe 在我将其作为 valgrind 调用时指向 usr/lib64/valgrind/amd64-linux/memcheck 吗？

在我的代码中，我试图从 pid 中获取可执行文件名，在这种情况下希望看到 valgrind。

Answer 1

memcheck 是 Valgrind 使用的默认工具，除非您告诉它使用其他工具，例如 callgrind。

使用--tool=<name> 指定您要调用的工具。

旁注：您的/usr/bin/valgrind 是否也是一个脚本，就像默认情况下一样？为什么不玩它来做你想要实现的目标？在我的系统上，首先调用/usr/bin/valgrind.bin，然后调用相应的（后端）工具（/usr/lib/valgrind/memcheck-amd64-linux）。

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来自strace的相关输出：

execve("/usr/bin/valgrind", ["valgrind", "./myprog"], [/* 35 vars */]) = 0
stat("/home/user/HEAD/myprog", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
execve("/usr/bin/valgrind.bin", ["/usr/bin/valgrind.bin", "./myprog"], [/* 39 vars */]) = 0
open("./myprog", O_RDONLY)              = 3
execve("/usr/lib/valgrind/memcheck-amd64-linux", ["/usr/bin/valgrind.bin", "./myprog"], [/* 40 vars */]) = 0
getcwd("/home/user/HEAD/myprog", 4095) = 25
open("./myprog", O_RDONLY)              = 3
stat("./myprog", {st_mode=S_IFREG|0755, st_size=1886240, ...}) = 0
readlink("/proc/self/fd/3", "/home/user/HEAD/myprog/myprog", 4096) = 31
readlink("/proc/self/fd/3", "/home/user/HEAD/myprog/myprog", 4096) = 31
open("./myprog", O_RDONLY)              = 3
write(1015, "./myprog", 8)              = 8
write(1016, "==23547== Command: ./myprog\n", 28==23547== Command: ./myprog
stat("/home/user/HEAD/myprog/myprog", {st_mode=S_IFREG|0755, st_size=1886240, ...}) = 0
open("/home/user/HEAD/myprog/myprog", O_RDONLY) = 3
stat("/home/user/HEAD/myprog/myprog", {st_mode=S_IFREG|0755, st_size=1886240, ...}) = 0
open("/home/user/HEAD/myprog/myprog", O_RDONLY) = 3
open("/home/user/HEAD/myprog/myprog", O_RDONLY) = 3
readlink("/proc/self/fd/3", "/home/user/HEAD/myprog/myprog", 4096) = 31
getcwd("/home/user/HEAD/myprog", 4096) = 25
lstat("/home/user/HEAD/myprog/myprog", {st_mode=S_IFREG|0755, st_size=1886240, ...}) = 0
open("/home/user/HEAD/myprog/datafile", O_RDONLY) = 3
access("/home/user/HEAD/myprog/datafile", F_OK) = 0
open("/home/user/HEAD/myprog/datafile", O_RDONLY) = 3
open("/home/user/HEAD/myprog/datafile", O_RDONLY) = 4

您会注意到所有execve 调用都不是指./myprog，而是指Valgrind 包装脚本、二进制文件和后端工具：

execve("/usr/bin/valgrind", ["valgrind", "./myprog"], [/* 35 vars */]) = 0
execve("/usr/bin/valgrind.bin", ["/usr/bin/valgrind.bin", "./myprog"], [/* 39 vars */]) = 0
execve("/usr/lib/valgrind/memcheck-amd64-linux", ["/usr/bin/valgrind.bin", "./myprog"], [/* 40 vars */]) = 0