Manual Pages  — CAP_RIGHTS_GET

cap_rights_get – obtain capability rights

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES EXAMPLES ERRORS SEE ALSO HISTORY AUTHORS

Standard C Library (libc, -lc)

#include <sys/capsicum.h>

int
cap_rights_get(int fd, cap_rights_t *rights);

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.

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);

cap_rights_get() succeeds unless:

[EBADF]
	The fd argument is not a valid active descriptor.
[EFAULT]
	The rights argument points at an invalid address.

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.

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