Zero-copy FTP/HTTP Daemon compatible with all POSIX systems
| 1 | /* |
| 2 | MIT License |
| 3 | |
| 4 | Copyright (c) 2026 Seregon |
| 5 | |
| 6 | Permission is hereby granted, free of charge, to any person obtaining a copy |
| 7 | of this software and associated documentation files (the "Software"), to deal |
| 8 | in the Software without restriction, including without limitation the rights |
| 9 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 10 | copies of the Software, and to permit persons to whom the Software is |
| 11 | furnished to do so, subject to the following conditions: |
| 12 | |
| 13 | The above copyright notice and this permission notice shall be included in all |
| 14 | copies or substantial portions of the Software. |
| 15 | |
| 16 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 17 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 18 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 19 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 20 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 21 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 22 | SOFTWARE. |
| 23 | */ |
| 24 | |
| 25 | /** |
| 26 | * @file ftp_session.h |
| 27 | * @brief FTP session management and lifecycle |
| 28 | * |
| 29 | * @author SeregonWar |
| 30 | * @version 1.0.0 |
| 31 | * @date 2026-02-13 |
| 32 | * |
| 33 | * DESIGN: Thread-per-client model with session pool |
| 34 | * THREADING: Each session runs in dedicated thread |
| 35 | * |
| 36 | */ |
| 37 | |
| 38 | #ifndef FTP_SESSION_H |
| 39 | #define FTP_SESSION_H |
| 40 | |
| 41 | #include "ftp_types.h" |
| 42 | |
| 43 | /*===========================================================================* |
| 44 | * SESSION LIFECYCLE |
| 45 | *===========================================================================*/ |
| 46 | |
| 47 | /** |
| 48 | * @brief Initialize session structure |
| 49 | * |
| 50 | * @param session Session to initialize |
| 51 | * @param ctrl_fd Control socket descriptor |
| 52 | * @param client_addr Client address information |
| 53 | * @param session_id Unique session identifier |
| 54 | * @param root_path Server root directory |
| 55 | * |
| 56 | * @return FTP_OK on success, negative error code on failure |
| 57 | * |
| 58 | * @pre session != NULL |
| 59 | * @pre ctrl_fd >= 0 |
| 60 | * @pre client_addr != NULL |
| 61 | * @pre root_path != NULL |
| 62 | * |
| 63 | * @post session->state == FTP_STATE_CONNECTED |
| 64 | * @post session->ctrl_fd == ctrl_fd |
| 65 | * @post All other file descriptors == -1 |
| 66 | */ |
| 67 | ftp_error_t ftp_session_init(ftp_session_t *session, |
| 68 | int ctrl_fd, |
| 69 | const struct sockaddr_in *client_addr, |
| 70 | uint32_t session_id, |
| 71 | const char *root_path); |
| 72 | |
| 73 | /** |
| 74 | * @brief Cleanup session resources |
| 75 | * |
| 76 | * @param session Session to cleanup |
| 77 | * |
| 78 | * @pre session != NULL |
| 79 | * |
| 80 | * @post All file descriptors closed |
| 81 | * @post Session state set to FTP_STATE_TERMINATING |
| 82 | * |
| 83 | * @note Thread-safety: Call only from session thread |
| 84 | */ |
| 85 | void ftp_session_cleanup(ftp_session_t *session); |
| 86 | |
| 87 | /** |
| 88 | * @brief Session thread entry point |
| 89 | * |
| 90 | * WORKFLOW: |
| 91 | * 1. Send greeting (220) |
| 92 | * 2. Command processing loop |
| 93 | * 3. Cleanup and exit |
| 94 | * |
| 95 | * @param arg Session pointer (ftp_session_t*) |
| 96 | * |
| 97 | * @return NULL |
| 98 | * |
| 99 | * @pre arg != NULL |
| 100 | * @pre arg points to valid ftp_session_t |
| 101 | * |
| 102 | * @note This function runs in a separate thread |
| 103 | */ |
| 104 | void* ftp_session_thread(void *arg); |
| 105 | |
| 106 | /*===========================================================================* |
| 107 | * REPLY SENDING |
| 108 | *===========================================================================*/ |
| 109 | |
| 110 | /** |
| 111 | * @brief Send FTP reply to client |
| 112 | * |
| 113 | * @param session Client session |
| 114 | * @param code FTP reply code |
| 115 | * @param message Reply message (NULL for default) |
| 116 | * |
| 117 | * @return FTP_OK on success, negative error code on failure |
| 118 | * |
| 119 | * @pre session != NULL |
| 120 | * @pre session->ctrl_fd >= 0 |
| 121 | * |
| 122 | * @note Thread-safety: Safe (session not shared) |
| 123 | * @note Blocks until entire reply sent |
| 124 | */ |
| 125 | ftp_error_t ftp_session_send_reply(ftp_session_t *session, |
| 126 | ftp_reply_code_t code, |
| 127 | const char *message); |
| 128 | |
| 129 | /** |
| 130 | * @brief Send multi-line reply to client |
| 131 | * |
| 132 | * Format: |
| 133 | * 123-First line |
| 134 | * Second line |
| 135 | * 123 Last line |
| 136 | * |
| 137 | * @param session Client session |
| 138 | * @param code FTP reply code |
| 139 | * @param lines Array of message lines |
| 140 | * @param count Number of lines |
| 141 | * |
| 142 | * @return FTP_OK on success, negative error code on failure |
| 143 | * |
| 144 | * @pre session != NULL |
| 145 | * @pre lines != NULL |
| 146 | * @pre count > 0 |
| 147 | */ |
| 148 | ftp_error_t ftp_session_send_multiline_reply(ftp_session_t *session, |
| 149 | ftp_reply_code_t code, |
| 150 | const char **lines, |
| 151 | size_t count); |
| 152 | |
| 153 | /*===========================================================================* |
| 154 | * DATA CONNECTION MANAGEMENT |
| 155 | *===========================================================================*/ |
| 156 | |
| 157 | /** |
| 158 | * @brief Open data connection |
| 159 | * |
| 160 | * Behavior depends on data_mode: |
| 161 | * - FTP_DATA_MODE_ACTIVE: Connect to client |
| 162 | * - FTP_DATA_MODE_PASSIVE: Accept from client |
| 163 | * |
| 164 | * @param session Client session |
| 165 | * |
| 166 | * @return FTP_OK on success, negative error code on failure |
| 167 | * |
| 168 | * @pre session != NULL |
| 169 | * @pre session->data_mode != FTP_DATA_MODE_NONE |
| 170 | * |
| 171 | * @post On success: session->data_fd >= 0 |
| 172 | */ |
| 173 | ftp_error_t ftp_session_open_data_connection(ftp_session_t *session); |
| 174 | |
| 175 | /** |
| 176 | * @brief Close data connection |
| 177 | * |
| 178 | * @param session Client session |
| 179 | * |
| 180 | * @pre session != NULL |
| 181 | * |
| 182 | * @post session->data_fd == -1 |
| 183 | * @post session->pasv_fd == -1 (if passive mode) |
| 184 | * @post session->data_mode == FTP_DATA_MODE_NONE |
| 185 | */ |
| 186 | void ftp_session_close_data_connection(ftp_session_t *session); |
| 187 | |
| 188 | /** |
| 189 | * @brief Send data via data connection |
| 190 | * |
| 191 | * @param session Client session |
| 192 | * @param buffer Data to send |
| 193 | * @param length Number of bytes to send |
| 194 | * |
| 195 | * @return Number of bytes sent, or negative error code |
| 196 | * |
| 197 | * @pre session != NULL |
| 198 | * @pre session->data_fd >= 0 |
| 199 | * @pre buffer != NULL |
| 200 | * @pre length > 0 |
| 201 | * |
| 202 | * @note May send less than requested (non-blocking) |
| 203 | */ |
| 204 | ssize_t ftp_session_send_data(ftp_session_t *session, |
| 205 | const void *buffer, |
| 206 | size_t length); |
| 207 | |
| 208 | /** |
| 209 | * @brief Receive data via data connection |
| 210 | * |
| 211 | * @param session Client session |
| 212 | * @param buffer Output buffer |
| 213 | * @param length Buffer size |
| 214 | * |
| 215 | * @return Number of bytes received, or negative error code |
| 216 | * |
| 217 | * @pre session != NULL |
| 218 | * @pre session->data_fd >= 0 |
| 219 | * @pre buffer != NULL |
| 220 | * @pre length > 0 |
| 221 | * |
| 222 | * @note May receive less than requested |
| 223 | */ |
| 224 | ssize_t ftp_session_recv_data(ftp_session_t *session, |
| 225 | void *buffer, |
| 226 | size_t length); |
| 227 | |
| 228 | /*===========================================================================* |
| 229 | * COMMAND PROCESSING |
| 230 | *===========================================================================*/ |
| 231 | |
| 232 | /** |
| 233 | * @brief Read command line from control connection |
| 234 | * |
| 235 | * Reads until CRLF sequence (\r\n). |
| 236 | * |
| 237 | * @param session Client session |
| 238 | * @param buffer Output buffer for command line |
| 239 | * @param size Size of output buffer |
| 240 | * |
| 241 | * @return Number of bytes read, or negative error code |
| 242 | * @retval >0 Command line read successfully |
| 243 | * @retval 0 Connection closed by client |
| 244 | * @retval <0 Error code |
| 245 | * |
| 246 | * @pre session != NULL |
| 247 | * @pre session->ctrl_fd >= 0 |
| 248 | * @pre buffer != NULL |
| 249 | * @pre size >= FTP_CMD_BUFFER_SIZE |
| 250 | * |
| 251 | * @post buffer contains null-terminated command line (CRLF removed) |
| 252 | * |
| 253 | * @note Blocks until complete line received |
| 254 | */ |
| 255 | ssize_t ftp_session_read_command(ftp_session_t *session, |
| 256 | char *buffer, |
| 257 | size_t size); |
| 258 | |
| 259 | /** |
| 260 | * @brief Process FTP command |
| 261 | * |
| 262 | * WORKFLOW: |
| 263 | * 1. Parse command line |
| 264 | * 2. Find command handler |
| 265 | * 3. Validate arguments |
| 266 | * 4. Execute command |
| 267 | * |
| 268 | * @param session Client session |
| 269 | * @param line Command line |
| 270 | * |
| 271 | * @return FTP_OK to continue, 1 to close session, negative on error |
| 272 | * |
| 273 | * @pre session != NULL |
| 274 | * @pre line != NULL |
| 275 | */ |
| 276 | int ftp_session_process_command(ftp_session_t *session, const char *line); |
| 277 | |
| 278 | #endif /* FTP_SESSION_H */ |
| 279 |