libs/nixio/src/splice.c

   1 /*
   2  * nixio - Linux I/O library for lua
   3  *
   4  *   Copyright (C) 2009 Steven Barth <steven@midlink.org>
   5  *
   6  *  Licensed under the Apache License, Version 2.0 (the "License");
   7  *  you may not use this file except in compliance with the License.
   8  *  You may obtain a copy of the License at
   9  *
  10  *      http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  *  Unless required by applicable law or agreed to in writing, software
  13  *  distributed under the License is distributed on an "AS IS" BASIS,
  14  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  *  See the License for the specific language governing permissions and
  16  *  limitations under the License.
  17  */
  18
  19 #define _GNU_SOURCE
  20
  21 #include "nixio.h"
  22 #include <fcntl.h>
  23 #include <sys/sendfile.h>
  24
  25 /* guess what sucks... */
  26 #ifdef __UCLIBC__
  27 #include <unistd.h>
  28 #include <sys/syscall.h>
  29 ssize_t splice(int __fdin, __off64_t *__offin, int __fdout,
  30         __off64_t *__offout, size_t __len, unsigned int __flags) {
  31         return syscall(__NR_splice, __fdin, __offin, __fdout, __offout, __len, __flags);
  32 }
  33 #endif /* __UCLIBC__ */
  34
  35 /**
  36  * Checks whether a flag is set in the table and translates it into a bitmap
  37  */
  38 static void nixio_splice_flags__w(lua_State *L, int *m, int f, const char *t) {
  39         lua_pushstring(L, t);
  40         lua_rawget(L, -2);
  41         if (lua_toboolean(L, -1)) {
  42                 *m |= f;
  43         }
  44         lua_pop(L, 1);
  45 }
  46
  47 /**
  48  * Translate integer to poll flags and vice versa
  49  */
  50 static int nixio_splice_flags(lua_State *L) {
  51         int flags = 0;
  52
  53         luaL_checktype(L, 1, LUA_TTABLE);
  54         lua_settop(L, 1);
  55         nixio_splice_flags__w(L, &flags, SPLICE_F_MOVE, "move");
  56         nixio_splice_flags__w(L, &flags, SPLICE_F_NONBLOCK, "nonblock");
  57         nixio_splice_flags__w(L, &flags, SPLICE_F_MORE, "more");
  58         lua_pushinteger(L, flags);
  59
  60         return 1;
  61 }
  62
  63 /**
  64  * splice(fd_in, fd_out, length, flags)
  65  */
  66 static int nixio_splice(lua_State *L) {
  67         int fd_in = nixio__checkfd(L, 1);
  68         int fd_out = nixio__checkfd(L, 2);
  69         size_t len = luaL_checkinteger(L, 3);
  70         int flags = luaL_optinteger(L, 4, 0);
  71
  72
  73         long spliced = splice(fd_in, NULL, fd_out, NULL, len, flags);
  74
  75         if (spliced < 0) {
  76                 return nixio__perror(L);
  77         }
  78
  79         lua_pushnumber(L, spliced);
  80         return 1;
  81 }
  82
  83 /**
  84  * sendfile(outfd, infd, length)
  85  */
  86 static int nixio_sendfile(lua_State *L) {
  87         int sockfd = nixio__checksockfd(L);
  88         int infd = nixio__checkfd(L, 2);
  89         size_t len = luaL_checkinteger(L, 3);
  90
  91         long spliced = sendfile(sockfd, infd, NULL, len);
  92
  93         if (spliced < 0) {
  94                 return nixio__perror(L);
  95         }
  96
  97         lua_pushnumber(L, spliced);
  98         return 1;
  99 }
 100
 101 /* module table */
 102 static const luaL_reg R[] = {
 103         {"splice",                      nixio_splice},
 104         {"splice_flags",        nixio_splice_flags},
 105         {"sendfile",            nixio_sendfile},
 106         {NULL,                  NULL}
 107 };
 108
 109 void nixio_open_splice(lua_State *L) {
 110         luaL_register(L, NULL, R);
 111 }