Commit 544fa1a2 authored by Ammar Faizi's avatar Ammar Faizi Committed by Paul E. McKenney
Browse files

tools/nolibc/sys: Implement `mmap()` and `munmap()` 



Implement mmap() and munmap(). Currently, they are only available for
architecures that have my_syscall6 macro. For architectures that don't
have, this function will return -1 with errno set to ENOSYS (Function
not implemented).

This has been tested on x86 and i386.

Notes for i386:
 1) The common mmap() syscall implementation uses __NR_mmap2 instead
    of __NR_mmap.

 2) The offset must be shifted-right by 12-bit.

Acked-by: default avatarWilly Tarreau <w@1wt.eu>
Signed-off-by: default avatarAmmar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent f4738ff7

tools/include/nolibc/sys.h

+62 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <asm/unistd.h>

#include <asm/signal.h>  // for SIGCHLD

#include <asm/ioctls.h>

#include <asm/mman.h>

#include <linux/fs.h>

#include <linux/loop.h>

#include <linux/time.h>
@@ -675,6 +676,67 @@ int mknod(const char *path, mode_t mode, dev_t dev) 
	return ret;

}



#ifndef MAP_SHARED

#define MAP_SHARED		0x01	/* Share changes */

#define MAP_PRIVATE		0x02	/* Changes are private */

#define MAP_SHARED_VALIDATE	0x03	/* share + validate extension flags */

#endif



#ifndef MAP_FAILED

#define MAP_FAILED ((void *)-1)

#endif



static __attribute__((unused))

void *sys_mmap(void *addr, size_t length, int prot, int flags, int fd,

	       off_t offset)

{

#ifndef my_syscall6

	/* Function not implemented. */

	return -ENOSYS;

#else



	int n;



#if defined(__i386__)

	n = __NR_mmap2;

	offset >>= 12;

#else

	n = __NR_mmap;

#endif



	return (void *)my_syscall6(n, addr, length, prot, flags, fd, offset);

#endif

}



static __attribute__((unused))

void *mmap(void *addr, size_t length, int prot, int flags, int fd, off_t offset)

{

	void *ret = sys_mmap(addr, length, prot, flags, fd, offset);



	if ((unsigned long)ret >= -4095UL) {

		SET_ERRNO(-(long)ret);

		ret = MAP_FAILED;

	}

	return ret;

}



static __attribute__((unused))

int sys_munmap(void *addr, size_t length)

{

	return my_syscall2(__NR_munmap, addr, length);

}



static __attribute__((unused))

int munmap(void *addr, size_t length)

{

	int ret = sys_munmap(addr, length);



	if (ret < 0) {

		SET_ERRNO(-ret);

		ret = -1;

	}

	return ret;

}



/*

 * int mount(const char *source, const char *target,