%%% @copyright 2012-2021 Michael Santos <michael.santos@gmail.com>
%%% Redistribution and use in source and binary forms, with or without
%%% modification, are permitted provided that the following conditions
%%% are met:
%%%
%%% 1. Redistributions of source code must retain the above copyright notice,
%%% this list of conditions and the following disclaimer.
%%%
%%% 2. Redistributions in binary form must reproduce the above copyright
%%% notice, this list of conditions and the following disclaimer in the
%%% documentation and/or other materials provided with the distribution.
%%%
%%% 3. Neither the name of the copyright holder nor the names of its
%%% contributors may be used to endorse or promote products derived from
%%% this software without specific prior written permission.
%%%
%%% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
%%% "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
%%% LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
%%% A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
%%% HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
%%% SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
%%% TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
%%% PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
%%% LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
%%% NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
%%% SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-module(perc).
-export([
kill/2,
getuid/0,
geteuid/0,
getgid/0,
getegid/0,
getgroups/0,
setgroups/1,
setresuid/3,
setresgid/3,
renice/2,
getpriority/2,
setpriority/3,
umask/0, umask/1,
getumask/0,
status/0,
getrlimit/1,
setrlimit/2,
% Linux only
prctl/3,
prlimit/4,
signalfd/1, signalfd/2,
sigaddset/1,
close/1
]).
-export_type([
int32_t/0,
pid_t/0,
posix/0,
priority/0,
uint32_t/0,
uint64_t/0
]).
-type posix() ::
'e2big'
| 'eacces'
| 'eaddrinuse'
| 'eaddrnotavail'
| 'eadv'
| 'eafnosupport'
| 'eagain'
| 'ealign'
| 'ealready'
| 'ebade'
| 'ebadf'
| 'ebadfd'
| 'ebadmsg'
| 'ebadr'
| 'ebadrpc'
| 'ebadrqc'
| 'ebadslt'
| 'ebfont'
| 'ebusy'
| 'ecapmode'
| 'echild'
| 'echrng'
| 'ecomm'
| 'econnaborted'
| 'econnrefused'
| 'econnreset'
| 'edeadlk'
| 'edeadlock'
| 'edestaddrreq'
| 'edirty'
| 'edom'
| 'edotdot'
| 'edquot'
| 'eduppkg'
| 'eexist'
| 'efault'
| 'efbig'
| 'ehostdown'
| 'ehostunreach'
| 'eidrm'
| 'einit'
| 'einprogress'
| 'eintr'
| 'einval'
| 'eio'
| 'eisconn'
| 'eisdir'
| 'eisnam'
| 'el2hlt'
| 'el2nsync'
| 'el3hlt'
| 'el3rst'
| 'elbin'
| 'elibacc'
| 'elibbad'
| 'elibexec'
| 'elibmax'
| 'elibscn'
| 'elnrng'
| 'eloop'
| 'emfile'
| 'emlink'
| 'emsgsize'
| 'emultihop'
| 'enametoolong'
| 'enavail'
| 'enet'
| 'enetdown'
| 'enetreset'
| 'enetunreach'
| 'enfile'
| 'enoano'
| 'enobufs'
| 'enocsi'
| 'enodata'
| 'enodev'
| 'enoent'
| 'enoexec'
| 'enolck'
| 'enolink'
| 'enomem'
| 'enomsg'
| 'enonet'
| 'enopkg'
| 'enoprotoopt'
| 'enospc'
| 'enosr'
| 'enostr'
| 'enosym'
| 'enosys'
| 'enotblk'
| 'enotcapable'
| 'enotconn'
| 'enotdir'
| 'enotempty'
| 'enotnam'
| 'enotrecoverable'
| 'enotsock'
| 'enotsup'
| 'enotty'
| 'enotuniq'
| 'enxio'
| 'eopnotsupp'
| 'eoverflow'
| 'eownerdead'
| 'eperm'
| 'epfnosupport'
| 'epipe'
| 'eproclim'
| 'eprocunavail'
| 'eprogmismatch'
| 'eprogunavail'
| 'eproto'
| 'eprotonosupport'
| 'eprototype'
| 'erange'
| 'erefused'
| 'eremchg'
| 'eremdev'
| 'eremote'
| 'eremoteio'
| 'eremoterelease'
| 'erofs'
| 'erpcmismatch'
| 'erremote'
| 'eshutdown'
| 'esocktnosupport'
| 'espipe'
| 'esrch'
| 'esrmnt'
| 'estale'
| 'esuccess'
| 'etime'
| 'etimedout'
| 'etoomanyrefs'
| 'etxtbsy'
| 'euclean'
| 'eunatch'
| 'eusers'
| 'eversion'
| 'ewouldblock'
| 'exdev'
| 'exfull'.
-type int32_t() :: -16#7fffffff..16#7fffffff.
-type uint32_t() :: 0..16#ffffffff.
-type uint64_t() :: 0..16#ffffffffffffffff.
-type pid_t() :: int32_t().
-on_load(on_load/0).
on_load() ->
erlang:load_nif(progname(), []).
%% @doc kill(2): send a signal to a Unix process
%%
%% Process IDs and signals are signed 32-bit integers. A signal
%% can also be the lower cased signal name as an atom.
%%
%% Sending a signal to PID 0 will send the signal to the Erlang VM.
-spec kill(pid_t(), atom() | integer()) -> ok | {error, posix()}.
kill(Pid, Signal) when is_integer(Signal) ->
kill_nif(Pid, Signal);
kill(Pid, Signal) when is_atom(Signal) ->
kill_nif(Pid, perc_signal:define(Signal)).
kill_nif(_, _) ->
erlang:nif_error(not_implemented).
%% @doc getpriority(2): get the process priority
%%
%% Get the priority (the "nice" value) of processes by pid, process
%% group or user.
-spec getpriority(int32_t(), int32_t()) -> {ok, int32_t()} | {error, posix()}.
getpriority(_, _) ->
erlang:nif_error(not_implemented).
%% @doc setpriority(2): set the process priority
%%
%% Set the priority (the "nice" value) of processes by pid, process
%% group or user.
-spec setpriority(int32_t(), int32_t(), int32_t()) -> ok | {error, posix()}.
setpriority(_, _, _) ->
erlang:nif_error(not_implemented).
%% @doc getuid(2): get user identity
-spec getuid() -> uint32_t().
getuid() ->
erlang:nif_error(not_implemented).
%% @doc geteuid(2): get effective user id
-spec geteuid() -> uint32_t().
geteuid() ->
erlang:nif_error(not_implemented).
%% @doc getgid(2): get group identity
-spec getgid() -> uint32_t().
getgid() ->
erlang:nif_error(not_implemented).
%% @doc getegid(2): get effective group id
-spec getegid() -> uint32_t().
getegid() ->
erlang:nif_error(not_implemented).
%% @doc getgroups(2): retrieve the list of supplementary groups
-spec getgroups() -> [uint32_t()].
getgroups() ->
erlang:nif_error(not_implemented).
%% @doc setgroups(2): set the list of supplementary groups
-spec setgroups([uint32_t()]) -> ok | {error, posix()}.
setgroups(_) ->
erlang:nif_error(not_implemented).
%% @doc setresuid(2): set real, effective and saved user id
-spec setresuid(uint32_t(), uint32_t(), uint32_t()) -> ok | {error, posix()}.
setresuid(_, _, _) ->
erlang:nif_error(not_implemented).
%% @doc setresgid(2): set real, effective and saved group id
-spec setresgid(uint32_t(), uint32_t(), uint32_t()) -> ok | {error, posix()}.
setresgid(_, _, _) ->
erlang:nif_error(not_implemented).
%% @doc renice: reset the process priority
%%
%% Convenience wrapper around getpriority/2 and setpriority/3,
%% similar to renice(1).
%%
%% WARNING: renice/2 makes successive calls to getpriority/2 and
%% setpriority/3. Since this sequence is not atomic, the priority
%% may change between calls or the process may have been terminated.
%%
%% Sets the priority of a process or processes by pid, pgroup or
%% user. The new priority may be an integer or a list containing a
%% relative priority, indicated by using a "+" or "-". For example,
%% using "+10" will increase the niceness of the process by 10.
-spec renice(priority(), string() | int32_t()) -> ok | {error, posix()}.
renice(Type, Priority) ->
{Which, Who} = prio(Type),
renice(Which, Who, Priority).
-spec renice(int32_t(), int32_t(), string() | int32_t()) -> ok | {error, posix()}.
renice(Which, Who, "+" ++ Priority) ->
case getpriority(Which, Who) of
{ok, OldPrio} ->
N = list_to_integer(Priority),
setpriority(Which, Who, OldPrio + N);
Error ->
Error
end;
renice(Which, Who, "-" ++ Priority) ->
case getpriority(Which, Who) of
{ok, OldPrio} ->
N = list_to_integer(Priority),
setpriority(Which, Who, OldPrio - N);
Error ->
Error
end;
renice(Which, Who, Priority) when is_list(Priority) ->
setpriority(Which, Who, list_to_integer(Priority));
renice(Which, Who, Priority) when is_integer(Priority) ->
setpriority(Which, Who, Priority).
%% @doc status: retrieve process status
%%
%% Reads /proc/self/status as a map.
-spec status() -> {ok, #{binary() => binary()}} | {error, atom()}.
status() ->
case file:read_file("/proc/self/status") of
{error, _} = Error ->
Error;
{ok, Status} ->
{ok,
maps:from_list(
[
list_to_tuple(binary:split(N, <<":\t">>))
|| N <- binary:split(Status, <<"\n">>, [global, trim]),
N /= <<>>
]
)}
end.
%% @doc getumask(3): safer version of umask/0
%%
%% Obtain the current process mask by parsing /proc/self/status,
%% avoiding the race condition in umask/0.
%%
%% If /proc/self/status does not exist or is not parsable, getumask/0
%% fails back to umask/0.
-spec getumask() -> int32_t().
getumask() ->
case status() of
{error, _} ->
umask();
{ok, Status} ->
case maps:find(<<"Umask">>, Status) of
error ->
umask();
{ok, Mask} ->
binary_to_integer(Mask, 8)
end
end.
%% @doc umask(2): get the process mask
%%
%% WARNING: umask/0 is destructive: the umask is retrieved by setting
%% the process mask to 0, then re-setting it back to the original
%% mask. Between the successive calls to umask(2), the process
%% mask is 0. An erlang process calling umask/0 concurrently with
%% a process creating a file may have unexpected results.
-spec umask() -> int32_t().
umask() ->
umask_nif().
umask_nif() ->
erlang:nif_error(not_implemented).
%% @doc umask(2): set the process mask
%%
%% Sets the file creation mask for beam. The mask may be either
%% an integer or a list representing an octal number, e.g., either
%% 8#022 or "022".
%%
%% The old mask value is returned. To retrieve the current umask,
%% use umask/0 or getumask/0.
-spec umask(string() | int32_t()) -> int32_t().
umask(Mask) when is_list(Mask) ->
umask(list_to_integer(Mask, 8));
umask(Mask) when is_integer(Mask) ->
umask_nif(Mask).
umask_nif(_) ->
erlang:nif_error(not_implemented).
%% @doc getrlimit(2): get process resource limits
%%
%% Get process limits for beam. See prlimit/4 for a list of the
%% resource atoms.
%%
%% The value returned is a struct rlimit:
%%
%% ```
%% 1> {ok, <<Soft:8/native-unsigned-integer-unit:8, Hard:8/native-unsigned-integer-unit:8>>} = perc:getrlimit(rlimit_nofile).
%% 2> Soft.
%% 1024
%% 3> Hard.
%% 4096
%% '''
-spec getrlimit(atom() | int32_t()) -> {ok, binary()} | {error, posix()}.
getrlimit(Resource) when is_atom(Resource) ->
getrlimit(perc_rlimit:define(Resource));
getrlimit(Resource) ->
% struct rlimit {
% rlim_t rlim_cur; /* Soft limit */
% rlim_t rlim_max; /* Hard limit (ceiling for rlim_cur) */
% };
Size = erlang:system_info({wordsize, external}),
getrlimit_nif(Resource, <<0:(16 * Size)>>).
getrlimit_nif(_, _) ->
erlang:nif_error(not_implemented).
%% @doc setrlimit(2): set process resource limits
%%
%% Set process limits for beam. See prlimit/4 for a list of the
%% resource atoms.
-spec setrlimit(atom() | int32_t(), atom() | int32_t()) -> {ok, binary()} | {error, posix()}.
setrlimit(Resource, Limit) when is_atom(Resource) ->
setrlimit(perc_rlimit:define(Resource), Limit);
setrlimit(Resource, Limit) ->
setrlimit_nif(Resource, Limit).
setrlimit_nif(_, _) ->
erlang:nif_error(not_implemented).
-spec prctl(int32_t(), uint32_t() | uint64_t(), binary()) -> ok | {error, posix()}.
prctl(_, _, _) ->
erlang:nif_error(not_implemented).
%% @doc prlimit(2): set resource limits for a specified process
%%
%% Linux only: on other platforms, {error, unsupported} will be
%% returned to the caller.
%%
%% Set or retrieve process limits for a process. Passing in an
%% empty binary for NewLimit or OldLimit indicates the caller is
%% not interested in these values.
%%
%% The binary size of NewLimit/OldLimit must otherwise match the size
%% of a struct rlimit for the platform. struct rlimit is usually
%% composed of two 8 byte values in native format. To retrieve the
%% current settings, pass in a zeroed 16 byte value.
-spec prlimit(pid_t(), atom() | int32_t(), binary(), binary()) ->
{ok, binary(), binary()} | {error, posix()}.
prlimit(Pid, Resource, New, Old) when is_atom(Resource) ->
prlimit(Pid, perc_rlimit:define(Resource), New, Old);
prlimit(Pid, Resource, New, Old) ->
prlimit_nif(Pid, Resource, New, Old).
prlimit_nif(_, _, _, _) ->
erlang:nif_error(not_implemented).
-spec sigaddset([atom() | int32_t()]) -> {ok, binary()} | {error, posix()}.
sigaddset(Signals) when is_list(Signals) ->
Signals1 = lists:map(
fun
(N) when is_integer(N) ->
N;
(N) when is_atom(N) ->
perc_signal:define(N)
end,
Signals
),
sigaddset_nif(Signals1).
sigaddset_nif(_) ->
erlang:nif_error(not_implemented).
-spec close(int32_t()) -> ok | {error, posix()}.
close(_) ->
erlang:nif_error(not_implemented).
-spec signalfd(binary()) -> {ok, int32_t()} | {error, posix()}.
signalfd(Mask) ->
signalfd(-1, Mask).
-spec signalfd(int32_t(), binary()) -> {ok, int32_t()} | {error, posix()}.
signalfd(Fd, Mask) ->
signalfd_nif(Fd, Mask).
signalfd_nif(_, _) ->
erlang:nif_error(not_implemented).
-type priority() ::
int32_t()
| {pid, int32_t()}
| {pgrp, int32_t()}
| {user, int32_t()}.
-spec prio(priority()) -> {int32_t(), int32_t()}.
prio({pid, N}) ->
{perc_prio:define(prio_process), N};
prio({pgrp, N}) ->
{perc_prio:define(prio_pgrp), N};
prio({user, N}) ->
{perc_prio:define(prio_user), N};
prio(N) when is_integer(N) ->
{perc_prio:define(prio_process), N}.
-spec progname() -> binary() | string().
progname() ->
case code:priv_dir(?MODULE) of
{error, bad_name} ->
filename:join([
filename:dirname(code:which(?MODULE)),
"..",
"priv",
?MODULE
]);
Dir ->
filename:join([Dir, ?MODULE])
end.
