linux-stable/include/uapi/linux/romfs_fs.h
Gustavo A. R. Silva 94dfc73e7c treewide: uapi: Replace zero-length arrays with flexible-array members
There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

-fstrict-flex-arrays=3 is coming and we need to land these changes
to prevent issues like these in the short future:

../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0,
but the source string has length 2 (including NUL byte) [-Wfortify-source]
		strcpy(de3->name, ".");
		^

Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If
this breaks anything, we can use a union with a new member name.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Build-tested-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/
Acked-by: Dan Williams <dan.j.williams@intel.com> # For ndctl.h
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2022-06-28 21:26:05 +02:00

60 lines
1.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef __LINUX_ROMFS_FS_H
#define __LINUX_ROMFS_FS_H
#include <linux/types.h>
#include <linux/fs.h>
/* The basic structures of the romfs filesystem */
#define ROMBSIZE BLOCK_SIZE
#define ROMBSBITS BLOCK_SIZE_BITS
#define ROMBMASK (ROMBSIZE-1)
#define ROMFS_MAGIC 0x7275
#define ROMFS_MAXFN 128
#define __mkw(h,l) (((h)&0x00ff)<< 8|((l)&0x00ff))
#define __mkl(h,l) (((h)&0xffff)<<16|((l)&0xffff))
#define __mk4(a,b,c,d) cpu_to_be32(__mkl(__mkw(a,b),__mkw(c,d)))
#define ROMSB_WORD0 __mk4('-','r','o','m')
#define ROMSB_WORD1 __mk4('1','f','s','-')
/* On-disk "super block" */
struct romfs_super_block {
__be32 word0;
__be32 word1;
__be32 size;
__be32 checksum;
char name[]; /* volume name */
};
/* On disk inode */
struct romfs_inode {
__be32 next; /* low 4 bits see ROMFH_ */
__be32 spec;
__be32 size;
__be32 checksum;
char name[];
};
#define ROMFH_TYPE 7
#define ROMFH_HRD 0
#define ROMFH_DIR 1
#define ROMFH_REG 2
#define ROMFH_SYM 3
#define ROMFH_BLK 4
#define ROMFH_CHR 5
#define ROMFH_SCK 6
#define ROMFH_FIF 7
#define ROMFH_EXEC 8
/* Alignment */
#define ROMFH_SIZE 16
#define ROMFH_PAD (ROMFH_SIZE-1)
#define ROMFH_MASK (~ROMFH_PAD)
#endif