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cap_fcntls_get(2) [freebsd man page]

CAP_FCNTLS_LIMIT(2)					      BSD System Calls Manual					       CAP_FCNTLS_LIMIT(2)

NAME
cap_fcntls_limit, cap_fcntls_get -- manage allowed fcntl commands LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <sys/capsicum.h> int cap_fcntls_limit(int fd, uint32_t fcntlrights); int cap_fcntls_get(int fd, uint32_t *fcntlrightsp); DESCRIPTION
If a file descriptor is granted the CAP_FCNTL capability right, the list of allowed fcntl(2) commands can be selectively reduced (but never expanded) with the cap_fcntls_limit() system call. A bitmask of allowed fcntls commands for a given file descriptor can be obtained with the cap_fcntls_get() system call. FLAGS
The following flags may be specified in the fcntlrights argument or returned in the fcntlrightsp argument: CAP_FCNTL_GETFL Permit F_GETFL command. CAP_FCNTL_SETFL Permit F_SETFL command. CAP_FCNTL_GETOWN Permit F_GETOWN command. CAP_FCNTL_SETOWN Permit F_SETOWN command. 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. ERRORS
cap_fcntls_limit() succeeds unless: [EBADF] The fd argument is not a valid descriptor. [EINVAL] An invalid flag has been passed in fcntlrights. [ENOTCAPABLE] fcntlrights would expand the list of allowed fcntl(2) commands. cap_fcntls_get() succeeds unless: [EBADF] The fd argument is not a valid descriptor. [EFAULT] The fcntlrightsp argument points at an invalid address. SEE ALSO
cap_ioctls_limit(2), cap_rights_limit(2), fcntl(2) HISTORY
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. BSD
March 27, 2014 BSD

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CAP_RIGHTS_LIMIT(2)					      BSD System Calls Manual					       CAP_RIGHTS_LIMIT(2)

NAME
cap_rights_limit -- limit capability rights LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <sys/capsicum.h> int cap_rights_limit(int fd, const cap_rights_t *rights); DESCRIPTION
When a file descriptor is created by a function such as accept(2), accept4(2), fhopen(2), kqueue(2), mq_open(2), open(2), openat(2), pdfork(2), pipe(2), shm_open(2), socket(2) or socketpair(2), it is assigned all capability rights. Those rights can be reduced (but never expanded) by using the cap_rights_limit() system call. Once capability rights are reduced, operations on the file descriptor will be limited to those permitted by rights. The rights argument should be prepared using cap_rights_init(3) family of functions. Capability rights assigned to a file descriptor can be obtained with the cap_rights_get(3) function. 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 to allow reading only. cap_rights_t setrights; char buf[1]; int fd; fd = open("/tmp/foo", O_RDWR); if (fd < 0) err(1, "open() failed"); if (cap_enter() < 0) err(1, "cap_enter() failed"); cap_rights_init(&setrights, CAP_READ); if (cap_rights_limit(fd, &setrights) < 0) err(1, "cap_rights_limit() failed"); buf[0] = 'X'; if (write(fd, buf, sizeof(buf)) > 0) errx(1, "write() succeeded!"); if (read(fd, buf, sizeof(buf)) < 0) err(1, "read() failed"); ERRORS
cap_rights_limit() succeeds unless: [EBADF] The fd argument is not a valid active descriptor. [EINVAL] An invalid right has been requested in rights. [ENOTCAPABLE] The rights argument contains capability rights not present for the given file descriptor. Capability rights list can only be reduced, never expanded. SEE ALSO
accept(2), accept4(2), cap_enter(2), fhopen(2), kqueue(2), mq_open(2), open(2), openat(2), pdfork(2), pipe(2), read(2), shm_open(2), socket(2), socketpair(2), write(2), cap_rights_get(3), cap_rights_init(3), err(3), capsicum(4), rights(4) HISTORY
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. BSD
March 27, 2014 BSD
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