bash 在 C 中获取 Linux 系统信息
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Get Linux system information in C
提问by user3574984
I have to check Linux system information. I can execute system commands in C, but doing so I create a new process for every one, which is pretty expensive. I was wondering if there is a way to obtain system information without being forced to execute a shell command. I've been looking around for a while and I found nothing. Actually, I'm not even sure if it's more convenient to execute commands via Bash calling them from my C program or find a way to accomplish the tasks using only C.
我必须检查Linux系统信息。我可以在 C 中执行系统命令，但是这样做我为每个人创建了一个新进程，这非常昂贵。我想知道是否有一种方法可以在不强制执行 shell 命令的情况下获取系统信息。我已经环顾了一段时间，但什么也没找到。实际上，我什至不确定是通过 Bash 从我的 C 程序中调用它们来执行命令还是找到一种仅使用 C 来完成任务的方法更方便。
回答by Tom van der Woerdt
Linux exposes a lotof information under /proc. You can read the data from there. For example, fopenthe file at /proc/cpuinfoand read its contents.
Linux的暴露了很多的信息下/proc。您可以从那里读取数据。例如，fopen文件位于/proc/cpuinfo并读取其内容。
回答by NlightNFotis
A presumably less known (and more complicated) way to do that, is that you can also use the api interface to sysctl. To use it under Linux, you need to #include <unistd.h>, #include <linux/sysctl.h>. A code example of that is available in the man page:
一种可能鲜为人知（且更复杂）的方法是，您还可以使用 api 接口来sysctl. 要在 Linux 下使用它，您需要#include <unistd.h>, #include <linux/sysctl.h>。手册页中提供了一个代码示例：
#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/sysctl.h>
int _sysctl(struct __sysctl_args *args );
#define OSNAMESZ 100
int
main(void)
{
struct __sysctl_args args;
char osname[OSNAMESZ];
size_t osnamelth;
int name[] = { CTL_KERN, KERN_OSTYPE };
memset(&args, 0, sizeof(struct __sysctl_args));
args.name = name;
args.nlen = sizeof(name)/sizeof(name[0]);
args.oldval = osname;
args.oldlenp = &osnamelth;
osnamelth = sizeof(osname);
if (syscall(SYS__sysctl, &args) == -1) {
perror("_sysctl");
exit(EXIT_FAILURE);
}
printf("This machine is running %*s\n", osnamelth, osname);
exit(EXIT_SUCCESS);
}
However, the man page linked also notes:
但是，链接的手册页还指出：
Glibc does not provide a wrapper for this system call; call it using syscall(2). Or rather... don't call it: use of this system call has long been discouraged, and it is so unloved that it is likely to disappear in a future kernel version. Since Linux 2.6.24, uses of this system call result in warnings in the kernel log. Remove it from your programs now; use the /proc/sys interface instead.
This system call is available only if the kernel was configured with the CONFIG_SYSCTL_SYSCALL option.
Glibc 没有为这个系统调用提供包装器；使用 syscall(2) 调用它。或者更确切地说......不要调用它：长期以来一直不鼓励使用这个系统调用，它是如此不受欢迎，以至于它可能会在未来的内核版本中消失。自 Linux 2.6.24 起，使用此系统调用会导致内核日志中出现警告。立即将其从您的程序中删除；改用 /proc/sys 接口。
仅当内核配置了 CONFIG_SYSCTL_SYSCALL 选项时，此系统调用才可用。
Please keep in mind that anything you can do with sysctl(), you can also just read()from /proc/sys. Also note that I do understand that the usefulness of that syscall is questionable, I just put it here for reference.
请记住，您可以使用的任何内容sysctl()，也可以read()仅从/proc/sys. 另请注意，我确实理解该系统调用的用处值得怀疑，我只是将其放在这里以供参考。
