cap_get_proc, cap_set_proc - POSIX capability manipulation
on processes
capgetp, capsetp - Linux specific capability manipulation
on arbitrary processes
SYNOPSIS
#include <sys/capability.h>
cap_t cap_get_proc(void);
int cap_set_proc(cap_t cap_p);
#undef _POSIX_SOURCE
#include <sys/capability.h>
cap_t capgetp(pid_t pid, cap_t cap_d);
cap_t capsetp(pid_t pid, cap_t cap_d);
USAGE
cc ... -lcap
DESCRIPTION
cap_get_proc allocates a capability state in working stor
age, sets its state to that of the calling process, and
returns a pointer to this newly created capability state.
The caller should free any releasable memory, when the
capability state in working storage is no longer required,
by calling cap_free with the cap_t as an argument.
cap_set_proc sets the values for all capability flags for
all capabilities with the capability state identified by
cap_p. The new capability state of the process will be
completely determined by the contents of cap_p upon suc
cessful return from this function. If any flag in cap_p
is set for any capability not currently permitted for the
calling process, the function will fail, and the capabil
ity state of the process will remain unchanged.
capgetp fills an existing cap_d, see cap_init(3), with the
process capabilities of the process indicated by pid.
This information can also be obtained from the
/proc/<pid>/status file.
capsetp attempts to set the capabilities of some other
process(es), pid. If pid is positive it refers to a spe
cific process; if it is zero, it refers to the current
process; -1 refers to all processes other than the current
process and process '1' (typically init(8)); other nega
tive values refer to the -pid process-group. In order to
use this function, the current process must have CAP_SETP
CAP raised in its Effective capability set. The capabili
ties set in the target process(es) are those contained in
RETURN VALUE
cap_get_proc returns a non-NULL value on success, and NULL
on failure.
cap_set_proc, capgetp and capsetp return zero for success,
and -1 on failure.
On failure, errno(3) is set to EINVAL, EPERM, or ENOMEM.
CONFORMING TO
cap_set_proc and cap_get_proc are functions specified in
the draft for POSIX.1e.
NOTES
The function capsetp should be used with care. It exists,
primarily, to overcome a lack of support for capabilities
in any of the filesystems supported by Linux. The seman
tics of this function may change as it is better under
stood. Please note, by default, the only processes that
have CAP_SETPCAP available to them are processes started
as a kernel-thread. (Typically this includes init(8),
kflushd and kswapd). You will need to recompile the kernel
to modify this default.
SEE ALSO
cap_clear(3), cap_copy_ext(3), cap_from_text(3),
cap_get_file(3), cap_init(3)
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