libs/nixio/src/file.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 #include "nixio.h"
  20 #include <errno.h>
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <sys/file.h>
  26
  27
  28 static int nixio_file(lua_State *L) {
  29         const char *filename = luaL_checklstring(L, 1, NULL);
  30         const char *mode = luaL_optlstring(L, 2, "r", NULL);
  31
  32         FILE *file = fopen(filename, mode);
  33         if (!file) {
  34                 return nixio__perror(L);
  35         }
  36
  37         FILE **udata = lua_newuserdata(L, sizeof(FILE*));
  38         if (!udata) {
  39                 return luaL_error(L, "out of memory");
  40         }
  41
  42         *udata = file;
  43
  44         luaL_getmetatable(L, NIXIO_FILE_META);
  45         lua_setmetatable(L, -2);
  46
  47         return 1;
  48 }
  49
  50 static int nixio_pipe(lua_State *L) {
  51         int pipefd[2];
  52         FILE **udata;
  53         if (pipe(pipefd)) {
  54                 return nixio__perror(L);
  55         }
  56
  57         luaL_getmetatable(L, NIXIO_FILE_META);
  58         udata = lua_newuserdata(L, sizeof(FILE*));
  59         if (!udata) {
  60                 return luaL_error(L, "out of memory");
  61         }
  62
  63         if (!(*udata = fdopen(pipefd[0], "r"))) {
  64                 return nixio__perror(L);
  65         }
  66         lua_pushvalue(L, -2);
  67         lua_setmetatable(L, -2);
  68
  69
  70         udata = lua_newuserdata(L, sizeof(FILE**));
  71         if (!(*udata = fdopen(pipefd[1], "w"))) {
  72                 return nixio__perror(L);
  73         }
  74         lua_pushvalue(L, -3);
  75         lua_setmetatable(L, -2);
  76
  77         return 2;
  78 }
  79
  80 static int nixio_file_write(lua_State *L) {
  81         int fd = nixio__checkfd(L, 1);
  82         size_t len;
  83         ssize_t sent;
  84         const char *data = luaL_checklstring(L, 2, &len);
  85
  86         do {
  87                 sent = write(fd, data, len);
  88         } while(sent == -1 && errno == EINTR);
  89         if (sent >= 0) {
  90                 lua_pushinteger(L, sent);
  91                 return 1;
  92         } else {
  93                 return nixio__perror(L);
  94         }
  95 }
  96
  97 static int nixio_file_read(lua_State *L) {
  98         int fd = nixio__checkfd(L, 1);
  99         char buffer[NIXIO_BUFFERSIZE];
 100         int req = luaL_checkinteger(L, 2);
 101         int readc;
 102
 103         /* We limit the readsize to NIXIO_BUFFERSIZE */
 104         req = (req > NIXIO_BUFFERSIZE) ? NIXIO_BUFFERSIZE : req;
 105
 106         do {
 107                 readc = read(fd, buffer, req);
 108         } while (readc == -1 && errno == EINTR);
 109
 110         if (readc < 0) {
 111                 return nixio__perror(L);
 112         } else {
 113                 lua_pushlstring(L, buffer, readc);
 114                 return 1;
 115         }
 116 }
 117
 118
 119 static int nixio_file_seek(lua_State *L) {
 120         FILE *f = nixio__checkfile(L);
 121         off_t len = (off_t)luaL_checknumber(L, 2);
 122         int whence;
 123         const char *whstr = luaL_optlstring(L, 3, "set", NULL);
 124         if (!strcmp(whstr, "set")) {
 125                 whence = SEEK_SET;
 126         } else if (!strcmp(whstr, "cur")) {
 127                 whence = SEEK_CUR;
 128         } else if (!strcmp(whstr, "end")) {
 129                 whence = SEEK_END;
 130         } else {
 131                 return luaL_argerror(L, 3, "supported values: set, cur, end");
 132         }
 133         return nixio__pstatus(L, !fseeko(f, len, whence));
 134 }
 135
 136 static int nixio_file_tell(lua_State *L) {
 137         FILE *f = nixio__checkfile(L);
 138         off_t pos = ftello(f);
 139         if (pos < 0) {
 140                 return nixio__perror(L);
 141         } else {
 142                 lua_pushnumber(L, (lua_Number)pos);
 143                 return 1;
 144         }
 145 }
 146
 147 static int nixio_file_flush(lua_State *L) {
 148         FILE *f = nixio__checkfile(L);
 149         return nixio__pstatus(L, !fflush(f));
 150 }
 151
 152 static int nixio_file_lock(lua_State *L) {
 153         int fd = fileno(nixio__checkfile(L));
 154
 155         const int j = lua_gettop(L);
 156         int flags = 0;
 157         for (int i=2; i<=j; i++) {
 158                 const char *flag = luaL_checkstring(L, i);
 159                 if (!strcmp(flag, "sh")) {
 160                         flags |= LOCK_SH;
 161                 } else if (!strcmp(flag, "ex")) {
 162                         flags |= LOCK_EX;
 163                 } else if (!strcmp(flag, "un")) {
 164                         flags |= LOCK_UN;
 165                 } else if (!strcmp(flag, "nb")) {
 166                         flags |= LOCK_NB;
 167                 } else {
 168                         return luaL_argerror(L, i, "supported values: sh, ex, un, nb");
 169                 }
 170         }
 171
 172         return nixio__pstatus(L, !flock(fd, flags));
 173 }
 174
 175 static int nixio_file_close(lua_State *L) {
 176         FILE **fpp = (FILE**)luaL_checkudata(L, 1, NIXIO_FILE_META);
 177         luaL_argcheck(L, *fpp, 1, "invalid file object");
 178         int res = fclose(*fpp);
 179         *fpp = NULL;
 180         return nixio__pstatus(L, !res);
 181 }
 182
 183 static int nixio_file__gc(lua_State *L) {
 184         FILE **fpp = (FILE**)luaL_checkudata(L, 1, NIXIO_FILE_META);
 185         if (*fpp) {
 186                 fclose(*fpp);
 187                 *fpp = NULL;
 188         }
 189         return 0;
 190 }
 191
 192 /**
 193  * string representation
 194  */
 195 static int nixio_file__tostring(lua_State *L) {
 196         lua_pushfstring(L, "nixio file %d", nixio__tofd(L, 1));
 197         return 1;
 198 }
 199
 200 /* method table */
 201 static const luaL_reg M[] = {
 202         {"write",               nixio_file_write},
 203         {"read",                nixio_file_read},
 204         {"tell",                nixio_file_tell},
 205         {"seek",                nixio_file_seek},
 206         {"flush",               nixio_file_flush},
 207         {"lock",                nixio_file_lock},
 208         {"close",               nixio_file_close},
 209         {"__gc",                nixio_file__gc},
 210         {"__tostring",  nixio_file__tostring},
 211         {NULL,                  NULL}
 212 };
 213
 214 /* module table */
 215 static const luaL_reg R[] = {
 216         {"open",                nixio_file},
 217         {"pipe",                nixio_pipe},
 218         {NULL,                  NULL}
 219 };
 220
 221 void nixio_open_file(lua_State *L) {
 222         luaL_register(L, NULL, R);
 223
 224         luaL_newmetatable(L, NIXIO_FILE_META);
 225         luaL_register(L, NULL, M);
 226         lua_pushvalue(L, -1);
 227         lua_setfield(L, -2, "__index");
 228         lua_setfield(L, -2, "meta_file");
 229 }