调用execv（）的时候时，动态分配的内存呢？ [英] What happens to dynamic allocated memory when calling execv()?

问题描述

我在写一个简单的shell作为操作系统的课程作业，我需要在PATH搜索找到该程序用户键入，一旦我找到合适的目录，我的malloc一块内存只够保存目录名加程序名称，我通过它作为execv（）的第一个参数。

I'm writing a simple shell as an OS course assignment, I need to search in the PATH to find the program user typed in, once I find the right directory, I malloc a piece of memory just enough to hold the directory name plus the program name, and I pass it as the first argument to execv().

我可以静态分配100个字符左右，但有一个限制，使我感到不舒服。所以，当execv（）执行，是堆清理或者是一块内存失去了什么？

I could have statically allocated 100 characters or so, but having a limit makes me feel uncomfortable. So when execv() executes, is the heap cleaned up or is that piece of memory lost?

这也许不是一个很大的内存，但我只是好奇。

It's maybe not a lot of memory but I'm just curious.

推荐答案

在执行exec（），整个过程是（A）结束，因此所有的资源，包括动态存储器和一些FD的如下，由操作系统回收，和（b）所取代：code，数据，线程，...

When you exec(), the entire process is (a) ended, so all resources including dynamic memory and some fd's as below, are reclaimed by the operating system, and (b) replaced: code, data, threads, ...

重新文件描述符，从男人的execve：

文件描述符调用的进程映像开放新照常开放
       过程映像，除了那些为其近距离on-exec标志设置
       （请参阅close（2）和fcntl（2））。即保持开放描述不受影响
       通过调用execve（）。

File descriptors open in the calling process image remain open in the new process image, except for those for which the close-on-exec flag is set (see close(2) and fcntl(2)). Descriptors that remain open are unaffected by execve().

这篇关于调用execv（）的时候时，动态分配的内存呢？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！