Commit 924e9539 authored by @wuzhangjin's avatar @wuzhangjin Committed by Willy Tarreau
Browse files

tools/nolibc: clean up mmap() routine 



Do several cleanups together:

- Since all supported architectures have my_syscall6() now, remove the
  #ifdef check.

- Move the mmap() related macros to tools/include/nolibc/types.h and
  reuse most of them from <linux/mman.h>

- Apply the new generic __sysret() to convert the calling of sys_map()
  to oneline code

Note, since MAP_FAILED is -1 on Linux, so we can use the generic
__sysret() which returns -1 upon error and still satisfy user land that
checks for MAP_FAILED.

Suggested-by: default avatarWilly Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20230702192347.GJ16233@1wt.eu/


Signed-off-by: default avatarZhangjin Wu <falcon@tinylab.org>
Signed-off-by: default avatarWilly Tarreau <w@1wt.eu>
parent 6591be4a

tools/include/nolibc/sys.h

+6 −23
Original line number Diff line number Diff line
@@ -636,26 +636,11 @@ int mknod(const char *path, mode_t mode, dev_t dev) 
	return __sysret(sys_mknod(path, mode, dev));

}



#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



#ifndef sys_mmap

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 (void *)-ENOSYS;

#else



	int n;



#if defined(__NR_mmap2)
@@ -666,20 +651,18 @@ void *sys_mmap(void *addr, size_t length, int prot, int flags, int fd, 
#endif



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

#endif

}

#endif



/* Note that on Linux, MAP_FAILED is -1 so we can use the generic __sysret()

 * which returns -1 upon error and still satisfy user land that checks for

 * MAP_FAILED.

 */



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;

	return (void *)__sysret((unsigned long)sys_mmap(addr, length, prot, flags, fd, offset));

}



static __attribute__((unused))

tools/include/nolibc/types.h

+6 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#define _NOLIBC_TYPES_H



#include "std.h"

#include <linux/mman.h>

#include <linux/time.h>

#include <linux/stat.h>
@@ -81,6 +82,11 @@ 
#define MAXPATHLEN     (PATH_MAX)

#endif



/* flags for mmap */

#ifndef MAP_FAILED

#define MAP_FAILED ((void *)-1)

#endif



/* whence values for lseek() */

#define SEEK_SET       0

#define SEEK_CUR       1