/*
* POSIX library for Lua 5.1, 5.2 & 5.3.
* (c) Gary V. Vaughan <gary@vaughan.pe>, 2013-2015
* (c) Reuben Thomas <rrt@sc3d.org> 2010-2013
* (c) Natanael Copa <natanael.copa@gmail.com> 2008-2010
* Clean up and bug fixes by Leo Razoumov <slonik.az@gmail.com> 2006-10-11
* Luiz Henrique de Figueiredo <lhf@tecgraf.puc-rio.br> 07 Apr 2006 23:17:49
* Based on original by Claudio Terra for Lua 3.x.
* With contributions by Roberto Ierusalimschy.
* With documentation from Steve Donovan 2012
*/
/***
Sys V Message Queue Operations.
Where supported by the underlying system, functions to send and receive
interprocess messages. If the module loads successfully, but there is
no system support, then `posix.sys.msg.version` will be set, but the
unsupported APIs wil be `nil`.
@module posix.sys.msg
*/
#include <config.h>
#include "_helpers.c" /* For LPOSIX_2001_COMPLIANT */
#if HAVE_SYSV_MESSAGING
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/types.h>
/***
Get a message queue identifier
@function msgget
@int key message queue id, or `IPC_PRIVATE` for a new queue
@int[opt=0] flags bitwise OR of zero or more from `IPC_CREAT` and `IPC_EXCL`,
and access permissions `S_IRUSR`, `S_IWUSR`, `S_IRGRP`, `S_IWGRP`, `S_IROTH`
and `S_IWOTH` (from @{posix.sys.stat})
@treturn[1] int message queue identifier, if successful
@return[2] nil
@treturn[2] string error message
@treturn[2] int errnum
@see msgget(2)
*/
static int
Pmsgget(lua_State *L)
{
checknargs (L, 2);
return pushresult(L, msgget(checkint(L, 1), optint(L, 2, 0)), "msgget");
}
/***
Send message to a message queue
@function msgsnd
@int id message queue identifier returned by @{msgget}
@int type arbitrary message type
@string message content
@int[opt=0] flags optionally `IPC_NOWAIT`
@treturn int 0, if successful
@return[2] nil
@treturn[2] string error message
@treturn[2] int errnum
@see msgsnd(2)
*/
static int
Pmsgsnd(lua_State *L)
{
void *ud;
lua_Alloc lalloc = lua_getallocf(L, &ud);
struct {
long mtype;
char mtext[0];
} *msg;
size_t len;
size_t msgsz;
ssize_t r;
int msgid = checkint(L, 1);
long msgtype = checklong(L, 2);
const char *msgp = luaL_checklstring(L, 3, &len);
int msgflg = optint(L, 4, 0);
checknargs(L, 4);
msgsz = sizeof(long) + len;
if ((msg = lalloc(ud, NULL, 0, msgsz)) == NULL)
return pusherror(L, "lalloc");
msg->mtype = msgtype;
memcpy(msg->mtext, msgp, len);
r = msgsnd(msgid, msg, msgsz, msgflg);
lua_pushinteger(L, r);
lalloc(ud, msg, msgsz, 0);
return (r == -1 ? pusherror(L, NULL) : 1);
}
/***
Receive message from a message queue
@function msgrcv
@int id message queue identifier returned by @{msgget}
@int size maximum message size
@int type message type (optional, default - 0)
@int[opt=0] flags bitwise OR of zero or more of `IPC_NOWAIT`, `MSG_EXCEPT`
and `MSG_NOERROR`
@treturn[1] int message type from @{msgsnd}
@treturn[1] string message text, if successful
@return[2] nil
@treturn[2] string error message
@treturn[2] int errnum
@see msgrcv(2)
*/
static int
Pmsgrcv(lua_State *L)
{
int msgid = checkint(L, 1);
size_t msgsz = checkint(L, 2);
long msgtyp = optint(L, 3, 0);
int msgflg = optint(L, 4, 0);
void *ud;
lua_Alloc lalloc;
struct {
long mtype;
char mtext[0];
} *msg;
checknargs(L, 4);
lalloc = lua_getallocf(L, &ud);
if ((msg = lalloc(ud, NULL, 0, msgsz)) == NULL)
return pusherror(L, "lalloc");
int res = msgrcv(msgid, msg, msgsz, msgtyp, msgflg);
if (res != -1)
{
lua_pushinteger(L, msg->mtype);
lua_pushlstring(L, msg->mtext, res - sizeof(long));
}
lalloc(ud, msg, msgsz, 0);
return (res == -1) ? pusherror(L, NULL) : 2;
}
#endif /*!HAVE_SYSV_MESSAGING*/
static const luaL_Reg posix_sys_msg_fns[] =
{
#if HAVE_SYSV_MESSAGING
LPOSIX_FUNC( Pmsgget ),
LPOSIX_FUNC( Pmsgsnd ),
LPOSIX_FUNC( Pmsgrcv ),
#endif
{NULL, NULL}
};
/***
Constants.
@section constants
*/
/***
Message constants.
Any constants not available in the underlying system will be `nil` valued.
@table posix.sys.msg
@int IPC_CREAT create entry if key does not exist
@int IPC_EXCL fail if key exists
@int IPC_PRIVATE private key
@int IPC_NOWAIT error if request must wait
@int MSG_EXCEPT read messages with differing type
@int MSG_NOERROR truncate received message rather than erroring
@usage
-- Print msg constants supported on this host.
for name, value in pairs (require "posix.sys.msg") do
if type (value) == "number" then
print (name, value)
end
end
*/
LUALIB_API int
luaopen_posix_sys_msg(lua_State *L)
{
luaL_register(L, "posix.sys.msg", posix_sys_msg_fns);
lua_pushliteral(L, "posix.sys.msg for " LUA_VERSION " / " PACKAGE_STRING);
lua_setfield(L, -2, "version");
#if HAVE_SYSV_MESSAGING
LPOSIX_CONST( IPC_CREAT );
LPOSIX_CONST( IPC_EXCL );
LPOSIX_CONST( IPC_PRIVATE );
LPOSIX_CONST( IPC_NOWAIT );
# ifdef MSG_EXCEPT
LPOSIX_CONST( MSG_EXCEPT );
# endif
# ifdef MSG_NOERROR
LPOSIX_CONST( MSG_NOERROR );
# endif
#endif
return 1;
}