cap_get_proc(3) -- Linux man page
NAMEcap_get_proc, cap_set_proc - POSIX capability manipulation on processes
int cap_set_proc(cap_t cap_p);
cap_t capgetp(pid_t pid, cap_t cap_d);
cap_t capsetp(pid_t pid, cap_t cap_d);
cc ... -lcap
DESCRIPTIONcap_get_proc allocates a capability state in working storage, 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 successful 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 capability 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 specific 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 negative values refer to the -pid process-group. In order to use this function, the current process must have CAP_SETPCAP raised in its Effective capability set. The capabilities set in the target process(es) are those contained in cap_d.
RETURN VALUEcap_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 TOcap_set_proc and cap_get_proc are functions specified in the draft for POSIX.1e.
NOTESThe 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 semantics of this function may change as it is better understood. 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 ALSOcap_clear(3), cap_copy_ext(3), cap_from_text(3), cap_get_file(3), cap_init(3)