Linux kernel module to comapre strings of 2 files

ajeet_singh · 12-04-2019, 01:34 AM

How to write program in C language to compare two strings in kernel only.

If possible please provide me sample code because I am new to this and need urgently.

Thanks in advance.

pan64 · 12-04-2019, 01:41 AM

probably this helps: https://blog.sourcerer.io/writing-a-...e-d9dc3762c234

jsbjsb001 · 12-04-2019, 03:25 AM

Quote:

Originally Posted by ajeet_singh

Thanks alot everyone.
Mainly the problem lies with the header file.

Well, I take it you didn't read posts #12 or #13 ?

FWIW, I don't understand why you want to use a kernel module for comparing two files either. As already said, you really should use/write a user space program instead of starting duplicate threads.

berndbausch · 12-04-2019, 06:53 AM

Quote:

Originally Posted by ajeet_singh

How to write program in C language to compare two strings in kernel only.

To compare two strings, you just compare each character of the strings. For example:

Code:

int compare(char *s1, char *s2)
{
    while (*s1!='\0' && *s2!='\0')
        if (*s1++ != *s2++) return NOTEQUAL;

    return *s1=='\0' && *s2=='\0' ? EQUAL : NOTEQUAL;
}

DISCLAIMER: My C is rusty and my head hurts.

ajeet_singh · 12-05-2019, 03:16 AM

Thanks @berndbausch for providing me code.

ehartman · 12-05-2019, 08:43 AM

Quote:

Originally Posted by ajeet_singh

I need C code for this. Since I am doing C code for kernel linux module, it gets difficult because syntax are changed. I am facing problem at every step so I want a fresh new code for this.

The kernel cannot use C library functions from a DYNAMIC library, like glibc.so
It must be completely contained within itself (except for loadable modules, of course, but it needs the "hooks" for those compiled in).