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sysctl

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#include <unistd.h>




#include <linux/sysctl.h>



int _sysctl(struct __sysctl_args *args);

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struct __sysctl_args {

    int    *name;    /* integer vector describing variable */

    int     nlen;    /* length of this vector */

    void   *oldval;  /* 0 or address where to store old value */

    size_t *oldlenp; /* available room for old value,

                        overwritten by actual size of old value */

    void   *newval;  /* 0 or address of new value */

    size_t  newlen;  /* size of new value */

};

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#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);

}

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