libcap/libcap.h

/*
 * Copyright (c) 1997 Andrew G Morgan <morgan@kernel.org>
 *
 * This file contains internal definitions for the various functions in
 * this small capability library.
 */

#ifndef LIBCAP_H
#define LIBCAP_H

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/capability.h>

#ifndef __u8
#define __u8    unsigned char
#endif /* __8 */

#ifndef __u32
#define __u32   unsigned int
#endif /* __u32 */

/* include the names for the caps and a definition of __CAP_BITS */
#include "cap_names.h"

/*
 * Do we match the local kernel?
 */

#if !defined(_LINUX_CAPABILITY_VERSION)

# error Kernel <linux/capability.h> does not support library
# error file "libcap.h" --> fix and recompile libcap

#elif (_LINUX_CAPABILITY_VERSION == 0x19980330)

# warning Kernel <linux/capability.h> does not support 64-bit capabilities
# warning and libcap is being built with no support for 64-bit capabilities

# ifndef _LINUX_CAPABILITY_VERSION_1
#  define _LINUX_CAPABILITY_VERSION_1 0x19980330
# endif

#elif (_LINUX_CAPABILITY_VERSION != 0x20071026)

# error Kernel <linux/capability.h> does not match library
# error file "libcap.h" --> fix and recompile libcap

#endif

/*
 * This is a pointer to a struct containing three consecutive
 * capability sets in the order of the cap_flag_t type: the are
 * effective,inheritable and permitted.  This is the type that the
 * user-space routines think of as 'internal' capabilities - this is
 * the type that is passed to the kernel with the system calls related
 * to processes.
 */

#ifndef _LINUX_CAPABILITY_U32S
# define _LINUX_CAPABILITY_U32S          1
#endif /* ndef _LINUX_CAPABILITY_U32S */

#if defined(VFS_CAP_REVISION_MASK) && !defined(VFS_CAP_U32)
# define VFS_CAP_U32_1                   1
# define XATTR_CAPS_SZ_1                 (sizeof(__le32)*(1 + 2*VFS_CAP_U32_1))
# define VFS_CAP_U32                     VFS_CAP_U32_1
struct _cap_vfs_cap_data {
    __le32 magic_etc;
    struct {
	__le32 permitted;
	__le32 inheritable;
    } data[VFS_CAP_U32_1];
};
# define vfs_cap_data                    _cap_vfs_cap_data
#endif

#ifndef CAP_TO_INDEX
# define CAP_TO_INDEX(x)     ((x) >> 5)  /* 1 << 5 == bits in __u32 */
#endif /* ndef CAP_TO_INDEX */

#ifndef CAP_TO_MASK
# define CAP_TO_MASK(x)      (1 << ((x) & 31))
#endif /* ndef CAP_TO_MASK */

#define NUMBER_OF_CAP_SETS      3   /* effective, inheritable, permitted */
#define __CAP_BLKS   (_LINUX_CAPABILITY_U32S)
#define CAP_SET_SIZE (__CAP_BLKS * sizeof(__u32))

#define CAP_T_MAGIC 0xCA90D0
struct _cap_struct {
    struct __user_cap_header_struct head;
    union {
	struct __user_cap_data_struct set;
	__u32 flat[NUMBER_OF_CAP_SETS];
    } u[_LINUX_CAPABILITY_U32S];
};

/* string magic for cap_free */
#define CAP_S_MAGIC 0xCA95D0

/*
 * kernel API cap set abstraction
 */

#define raise_cap(x,set)   u[(x)>>5].flat[set]       |=  (1<<((x)&31))
#define lower_cap(x,set)   u[(x)>>5].flat[set]       &= ~(1<<((x)&31))
#define isset_cap(y,x,set) ((y)->u[(x)>>5].flat[set] &   (1<<((x)&31)))

/*
 * Private definitions for internal use by the library.
 */

#define __libcap_check_magic(c,magic) ((c) && *(-1+(__u32 *)(c)) == (magic))
#define good_cap_t(c)        __libcap_check_magic(c, CAP_T_MAGIC)
#define good_cap_string(c)   __libcap_check_magic(c, CAP_S_MAGIC)

/*
 * library debugging
 */
#ifdef DEBUG

#include <stdio.h>
# define _cap_debug(f, x...)  do { \
    fprintf(stderr, __FUNCTION__ "(" __FILE__ ":%d): ", __LINE__); \
    fprintf(stderr, f, ## x); \
    fprintf(stderr, "\n"); \
} while (0)

# define _cap_debugcap(s, c, set) do { \
    unsigned _cap_index; \
    fprintf(stderr, __FUNCTION__ "(" __FILE__ ":%d): " s, __LINE__); \
    for (_cap_index=_LINUX_CAPABILITY_U32S; _cap_index-- > 0; ) { \
       fprintf(stderr, "%08x", (c).u[_cap_index].flat[set]); \
    } \
    fprintf(stderr, "\n"); \
} while (0)

#else /* !DEBUG */

# define _cap_debug(f, x...)
# define _cap_debugcap(s, c, set)

#endif /* DEBUG */

extern char *_libcap_strdup(const char *text);

/*
 * These are semi-public prototypes, they will only be defined in
 * <sys/capability.h> if _POSIX_SOURCE is not #define'd, so we
 * place them here too.
 */

extern int capset(cap_user_header_t header, cap_user_data_t data);
extern int capget(cap_user_header_t header, const cap_user_data_t data);
extern int capgetp(pid_t pid, cap_t cap_d);
extern int capsetp(pid_t pid, cap_t cap_d);

#endif /* LIBCAP_H */