mhd_read_file.c (5433B)
1 /* SPDX-License-Identifier: LGPL-2.1-or-later OR (GPL-2.0-or-later WITH eCos-exception-2.0) */ 2 /* 3 This file is part of GNU libmicrohttpd. 4 Copyright (C) 2024 Evgeny Grin (Karlson2k) 5 6 GNU libmicrohttpd is free software; you can redistribute it and/or 7 modify it under the terms of the GNU Lesser General Public 8 License as published by the Free Software Foundation; either 9 version 2.1 of the License, or (at your option) any later version. 10 11 GNU libmicrohttpd is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 Lesser General Public License for more details. 15 16 Alternatively, you can redistribute GNU libmicrohttpd and/or 17 modify it under the terms of the GNU General Public License as 18 published by the Free Software Foundation; either version 2 of 19 the License, or (at your option) any later version, together 20 with the eCos exception, as follows: 21 22 As a special exception, if other files instantiate templates or 23 use macros or inline functions from this file, or you compile this 24 file and link it with other works to produce a work based on this 25 file, this file does not by itself cause the resulting work to be 26 covered by the GNU General Public License. However the source code 27 for this file must still be made available in accordance with 28 section (3) of the GNU General Public License v2. 29 30 This exception does not invalidate any other reasons why a work 31 based on this file might be covered by the GNU General Public 32 License. 33 34 You should have received copies of the GNU Lesser General Public 35 License and the GNU General Public License along with this library; 36 if not, see <https://www.gnu.org/licenses/>. 37 */ 38 39 /** 40 * @file src/mhd2/mhd_read_file.c 41 * @brief The implementation of mhd_read_file() function 42 * @author Karlson2k (Evgeny Grin) 43 */ 44 45 #include "mhd_sys_options.h" 46 47 #include "mhd_read_file.h" 48 49 #include <stdlib.h> 50 #ifdef HAVE_UNISTD_H 51 # include <unistd.h> 52 #endif 53 54 #if ! defined(mhd_W32_NATIVE) 55 # include "mhd_limits.h" 56 #else 57 /* Native W32 */ 58 # include <windows.h> 59 # include <string.h> /* for memset() */ 60 # include <io.h> /* for _get_osfhandle() */ 61 #endif 62 63 MHD_INTERNAL MHD_FN_MUST_CHECK_RESULT_ MHD_FN_PAR_NONNULL_ALL_ 64 MHD_FN_PAR_OUT_SIZE_ (4, 3) MHD_FN_PAR_OUT_ (5) enum mhd_FileReadResult 65 mhd_read_file (int file_fd, 66 uint_fast64_t offset, 67 size_t buf_size, 68 char buf[MHD_FN_PAR_DYN_ARR_SIZE_ (buf_size)], 69 size_t *restrict size_filled) 70 { 71 #if (defined(HAVE_PREAD64) || defined(HAVE_PREAD)) && ! defined(mhd_W32_NATIVE) 72 # ifdef HAVE_PREAD64 73 const off64_t pos_off = (off64_t) offset; 74 # else /* HAVE_PREAD */ 75 const off_t pos_off = (off_t) offset; 76 # endif /* HAVE_PREAD */ 77 ssize_t res; 78 79 *size_filled = 0; 80 81 if ((0 > pos_off) || 82 (offset != (uint_fast64_t) pos_off)) 83 return mhd_FILE_READ_OFFSET_TOO_LARGE; 84 85 if (0 > (ssize_t) buf_size) 86 buf_size = SSIZE_MAX; /* Larger sizes may result in undefined behaviour */ 87 88 # ifdef HAVE_PREAD64 89 res = pread64 (file_fd, 90 buf, 91 buf_size, 92 pos_off); 93 # else /* HAVE_PREAD */ 94 res = pread (file_fd, 95 buf, 96 buf_size, 97 pos_off); 98 # endif /* HAVE_PREAD */ 99 100 if (0 > res) 101 return mhd_FILE_READ_ERROR; 102 103 if (0 == res) 104 return mhd_FILE_READ_EOF; 105 106 *size_filled = (size_t) res; 107 return mhd_FILE_READ_OK; 108 #elif ! defined(mhd_W32_NATIVE) 109 /* Multithread-unsafe emulation */ 110 # ifdef HAVE_LSEEK64 111 const off64_t pos_off = (off64_t) offset; 112 # else 113 const off_t pos_off = (off_t) offset; 114 # endif 115 ssize_t res; 116 117 *size_filled = 0; 118 119 if ((0 > pos_off) || 120 (offset != (uint_fast64_t) pos_off)) 121 return mhd_FILE_READ_OFFSET_TOO_LARGE; 122 123 if (0 > (ssize_t) buf_size) 124 buf_size = SSIZE_MAX; /* Larger sizes may result in undefined behaviour */ 125 126 # ifdef HAVE_LSEEK64 127 if (pos_off != lseek64 (file_fd, 128 pos_off, 129 SEEK_SET)) 130 return mhd_FILE_READ_ERROR; 131 # else 132 if (pos_off != lseek (file_fd, 133 pos_off, 134 SEEK_SET)) 135 return mhd_FILE_READ_ERROR; 136 # endif 137 138 res = read (file_fd, 139 buf, 140 buf_size); 141 142 if (0 > res) 143 return mhd_FILE_READ_ERROR; 144 145 if (0 == res) 146 return mhd_FILE_READ_EOF; 147 148 *size_filled = (size_t) res; 149 return mhd_FILE_READ_OK; 150 151 #else /* Native W32 */ 152 const intptr_t sys_fd = _get_osfhandle (file_fd); 153 const HANDLE w_hndl = (HANDLE) sys_fd; 154 OVERLAPPED ovrlp; 155 DWORD reqReadSize; 156 DWORD resReadSize; 157 158 *size_filled = 0; 159 if ((((intptr_t) -2) == sys_fd) || 160 (INVALID_HANDLE_VALUE == w_hndl)) 161 return mhd_FILE_READ_ERROR; 162 163 memset (&ovrlp, 0, sizeof(ovrlp)); 164 reqReadSize = (DWORD) buf_size; 165 if (reqReadSize != buf_size) 166 reqReadSize = (DWORD) (~((DWORD) 0)); 167 ovrlp.Offset = (DWORD) offset; 168 offset >>= 32; 169 ovrlp.OffsetHigh = (DWORD) offset; 170 if (0 != (offset >> 32)) 171 return mhd_FILE_READ_OFFSET_TOO_LARGE; 172 173 if (! ReadFile (w_hndl, 174 buf, 175 reqReadSize, 176 &resReadSize, 177 &ovrlp)) 178 return mhd_FILE_READ_ERROR; 179 180 if (0 == resReadSize) 181 return mhd_FILE_READ_EOF; 182 183 *size_filled = resReadSize; 184 return mhd_FILE_READ_OK; 185 #endif /* Native W32 */ 186 }