syscall.c

来自「linux 内核源代码」· C语言 代码 · 共 154 行

/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Licensed under the GPL
 */

#include "linux/file.h"
#include "linux/fs.h"
#include "linux/mm.h"
#include "linux/sched.h"
#include "linux/utsname.h"
#include "asm/current.h"
#include "asm/mman.h"
#include "asm/uaccess.h"
#include "asm/unistd.h"

/*  Unlocked, I don't care if this is a bit off */
int nsyscalls = 0;

long sys_fork(void)
{
	long ret;

	current->thread.forking = 1;
	ret = do_fork(SIGCHLD, UPT_SP(&current->thread.regs.regs),
		      &current->thread.regs, 0, NULL, NULL);
	current->thread.forking = 0;
	return ret;
}

long sys_vfork(void)
{
	long ret;

	current->thread.forking = 1;
	ret = do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD,
		      UPT_SP(&current->thread.regs.regs),
		      &current->thread.regs, 0, NULL, NULL);
	current->thread.forking = 0;
	return ret;
}

/* common code for old and new mmaps */
long sys_mmap2(unsigned long addr, unsigned long len,
	       unsigned long prot, unsigned long flags,
	       unsigned long fd, unsigned long pgoff)
{
	long error = -EBADF;
	struct file * file = NULL;

	flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
	if (!(flags & MAP_ANONYMOUS)) {
		file = fget(fd);
		if (!file)
			goto out;
	}

	down_write(&current->mm->mmap_sem);
	error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
	up_write(&current->mm->mmap_sem);

	if (file)
		fput(file);
 out:
	return error;
}

long old_mmap(unsigned long addr, unsigned long len,
	      unsigned long prot, unsigned long flags,
	      unsigned long fd, unsigned long offset)
{
	long err = -EINVAL;
	if (offset & ~PAGE_MASK)
		goto out;

	err = sys_mmap2(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
 out:
	return err;
}
/*
 * sys_pipe() is the normal C calling standard for creating
 * a pipe. It's not the way unix traditionally does this, though.
 */
long sys_pipe(unsigned long __user * fildes)
{
	int fd[2];
	long error;

	error = do_pipe(fd);
	if (!error) {
		if (copy_to_user(fildes, fd, sizeof(fd)))
			error = -EFAULT;
	}
	return error;
}


long sys_uname(struct old_utsname __user * name)
{
	long 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;
}

long sys_olduname(struct oldold_utsname __user * name)
{
	long 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;
}

int kernel_execve(const char *filename, char *const argv[], char *const envp[])
{
	mm_segment_t fs;
	int ret;

	fs = get_fs();
	set_fs(KERNEL_DS);
	ret = um_execve(filename, argv, envp);
	set_fs(fs);

	return ret;
}