NAME

cap_rights_get — obtain capability rights

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <sys/capsicum.h>

int
cap_rights_get(int fd, cap_rights_t *rights);

DESCRIPTION

The cap_rights_get function allows to obtain current capability rights for the given descriptor. The function will fill the rights argument with all capability rights if they were not limited or capability rights configured during the last successful call of cap_rights_limit(2) on the given descriptor.

The rights argument can be inspected using cap_rights_init(3) family of functions.

The complete list of the capability rights can be found in the rights(4) manual page.

RETURN VALUES

Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

EXAMPLES

The following example demonstrates how to limit file descriptor capability rights and how to obtain them.

cap_rights_t setrights, getrights;
int fd;

memset(&setrights, 0, sizeof(setrights));
memset(&getrights, 0, sizeof(getrights));

fd = open("/tmp/foo", O_RDONLY);
if (fd < 0)
	err(1, "open() failed");

cap_rights_init(&setrights, CAP_FSTAT, CAP_READ);
if (cap_rights_limit(fd, &setrights) < 0 && errno != ENOSYS)
	err(1, "cap_rights_limit() failed");

if (cap_rights_get(fd, &getrights) < 0 && errno != ENOSYS)
	err(1, "cap_rights_get() failed");

assert(memcmp(&setrights, &getrights, sizeof(setrights)) == 0);

ERRORS

cap_rights_get() succeeds unless:

[EBADF]

The fd argument is not a valid active descriptor.

[EFAULT]

The rights argument points at an invalid address.

SEE ALSO

cap_rights_limit(2), errno(2), open(2), assert(3), cap_rights_init(3), err(3), memcmp(3), memset(3), capsicum(4), rights(4)

HISTORY

The cap_rights_get() function first appeared in FreeBSD 9.2. Support for capabilities and capabilities mode was developed as part of the TrustedBSD Project.

AUTHORS

This function was created by Pawel Jakub Dawidek <pawel@dawidek.net> under sponsorship of the FreeBSD Foundation.