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

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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: Willy Tarreau <w@1wt.eu>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Ammar Faizi 2022-03-29 17:17:33 +07:00 committed by Paul E. McKenney
parent f4738ff74c
commit 544fa1a2d3
1 changed files with 62 additions and 0 deletions
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62
tools/include/nolibc/sys.h
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@ -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,