arch/x86/kernel/sys_i386_32.c

/*
 * This file contains various random system calls that
 * have a non-standard calling sequence on the Linux/i386
 * platform.
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/syscalls.h>
#include <linux/mman.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <linux/ipc.h>

#include <linux/uaccess.h>
#include <linux/unistd.h>

#include <asm/syscalls.h>

/*
 * Old cruft
 */
asmlinkage int sys_uname(struct old_utsname __user *name)
{
	int err;
	if (!name)
		return -EFAULT;
	down_read(&uts_sem);
	err = copy_to_user(name, utsname(), sizeof(*name));
	up_read(&uts_sem);
	return err? -EFAULT:0;
}

asmlinkage int sys_olduname(struct oldold_utsname __user *name)
{
	int error;

	if (!name)
		return -EFAULT;
	if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname)))
		return -EFAULT;

	down_read(&uts_sem);

	error = __copy_to_user(&name->sysname, &utsname()->sysname,
			       __OLD_UTS_LEN);
	error |= __put_user(0, name->sysname + __OLD_UTS_LEN);
	error |= __copy_to_user(&name->nodename, &utsname()->nodename,
				__OLD_UTS_LEN);
	error |= __put_user(0, name->nodename + __OLD_UTS_LEN);
	error |= __copy_to_user(&name->release, &utsname()->release,
				__OLD_UTS_LEN);
	error |= __put_user(0, name->release + __OLD_UTS_LEN);
	error |= __copy_to_user(&name->version, &utsname()->version,
				__OLD_UTS_LEN);
	error |= __put_user(0, name->version + __OLD_UTS_LEN);
	error |= __copy_to_user(&name->machine, &utsname()->machine,
				__OLD_UTS_LEN);
	error |= __put_user(0, name->machine + __OLD_UTS_LEN);

	up_read(&uts_sem);

	error = error ? -EFAULT : 0;

	return error;
}


/*
 * Do a system call from kernel instead of calling sys_execve so we
 * end up with proper pt_regs.
 */
int kernel_execve(const char *filename, char *const argv[], char *const envp[])
{
	long __res;
	asm volatile ("push %%ebx ; movl %2,%%ebx ; int $0x80 ; pop %%ebx"
	: "=a" (__res)
	: "0" (__NR_execve), "ri" (filename), "c" (argv), "d" (envp) : "memory");
	return __res;
}