Sean Middleditch | a7a6b31 | 2009-03-16 12:49:50 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Sean Middleditch |
| 3 | * sean@sourcemud.org |
| 4 | * |
| 5 | * The author or authors of this code dedicate any and all copyright interest |
| 6 | * in this code to the public domain. We make this dedication for the benefit |
| 7 | * of the public at large and to the detriment of our heirs and successors. We |
| 8 | * intend this dedication to be an overt act of relinquishment in perpetuity of |
| 9 | * all present and future rights to this code under copyright law. |
| 10 | */ |
| 11 | |
| 12 | #include <sys/socket.h> |
| 13 | #include <netinet/in.h> |
| 14 | #include <arpa/inet.h> |
| 15 | #include <poll.h> |
| 16 | #include <errno.h> |
| 17 | #include <stdio.h> |
| 18 | #include <string.h> |
| 19 | #include <stdlib.h> |
| 20 | #include <ctype.h> |
| 21 | #include <unistd.h> |
| 22 | |
| 23 | #ifdef HAVE_ZLIB |
| 24 | #include "zlib.h" |
| 25 | #endif |
| 26 | |
| 27 | #include "libtelnet.h" |
| 28 | |
| 29 | #define MAX_USERS 64 |
| 30 | #define LINEBUFFER_SIZE 256 |
| 31 | |
| 32 | struct user_t { |
| 33 | char *name; |
| 34 | int sock; |
| 35 | libtelnet_t telnet; |
| 36 | char linebuf[256]; |
| 37 | int linepos; |
| 38 | }; |
| 39 | |
| 40 | static struct user_t users[MAX_USERS]; |
| 41 | |
| 42 | static void linebuffer_push(char *buffer, size_t size, int *linepos, |
| 43 | char ch, void (*cb)(const char *line, int overflow, void *ud), |
| 44 | void *ud) { |
| 45 | |
| 46 | /* CRLF -- line terminator */ |
| 47 | if (ch == '\n' && *linepos > 0 && buffer[*linepos - 1] == '\r') { |
| 48 | /* NUL terminate (replaces \r in buffer), notify app, clear */ |
| 49 | buffer[*linepos - 1] = 0; |
| 50 | cb(buffer, 0, ud); |
| 51 | *linepos = 0; |
| 52 | |
| 53 | /* CRNUL -- just a CR */ |
| 54 | } else if (ch == 0 && *linepos > 0 && buffer[*linepos - 1] == '\r') { |
| 55 | /* do nothing, the CR is already in the buffer */ |
| 56 | |
| 57 | /* anything else (including technically invalid CR followed by |
| 58 | * anything besides LF or NUL -- just buffer if we have room |
| 59 | * \r |
| 60 | */ |
| 61 | } else if (*linepos != size) { |
| 62 | buffer[(*linepos)++] = ch; |
| 63 | |
| 64 | /* buffer overflow */ |
| 65 | } else { |
| 66 | /* terminate (NOTE: eats a byte), notify app, clear buffer */ |
| 67 | buffer[size - 1] = 0; |
| 68 | cb(buffer, size - 1, ud); |
| 69 | *linepos = 0; |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | static void _message(const char *from, const char *msg) { |
| 74 | int i; |
| 75 | for (i = 0; i != MAX_USERS; ++i) { |
| 76 | if (users[i].sock != -1) { |
| 77 | libtelnet_send_printf(&users[i].telnet, "%s: %s\r\n", |
| 78 | from, msg); |
| 79 | } |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | static void _send(int sock, unsigned char *buffer, unsigned int size) { |
| 84 | int rs; |
| 85 | |
| 86 | /* ignore on invalid socket */ |
| 87 | if (sock == -1) |
| 88 | return; |
| 89 | |
| 90 | /* send data */ |
| 91 | while (size > 0) { |
| 92 | if ((rs = send(sock, buffer, size, 0)) == -1) { |
| 93 | if (errno != EINTR && errno != ECONNRESET) { |
| 94 | fprintf(stderr, "send() failed: %s\n", strerror(errno)); |
| 95 | exit(1); |
| 96 | } else { |
| 97 | return; |
| 98 | } |
| 99 | } else if (rs == 0) { |
| 100 | fprintf(stderr, "send() unexpectedly returned 0\n"); |
| 101 | exit(1); |
| 102 | } |
| 103 | |
| 104 | /* update pointer and size to see if we've got more to send */ |
| 105 | buffer += rs; |
| 106 | size -= rs; |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | /* process input line */ |
| 111 | static void _online(const char *line, int overflow, void *ud) { |
| 112 | struct user_t *user = (struct user_t*)ud; |
| 113 | int i; |
| 114 | |
| 115 | /* if the user has no name, this is his "login" */ |
| 116 | if (user->name == 0) { |
| 117 | /* must not be empty, must be at least 32 chars */ |
| 118 | if (strlen(line) == 0 || strlen(line) > 32) { |
| 119 | libtelnet_send_printf(&user->telnet, |
| 120 | "Invalid name.\r\nEnter name: "); |
| 121 | return; |
| 122 | } |
| 123 | |
| 124 | /* must not already be in use */ |
| 125 | for (i = 0; i != MAX_USERS; ++i) { |
| 126 | if (users[i].name != 0 && strcmp(users[i].name, line) == 0) { |
| 127 | libtelnet_send_printf(&user->telnet, |
| 128 | "Name in use.\r\nEnter name: "); |
| 129 | return; |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | /* keep name */ |
| 134 | user->name = strdup(line); |
| 135 | libtelnet_send_printf(&user->telnet, "Welcome, %s!\r\n", line); |
| 136 | return; |
| 137 | } |
| 138 | |
| 139 | /* if line is "quit" then, well, quit */ |
| 140 | if (strcmp(line, "quit") == 0) { |
| 141 | close(user->sock); |
| 142 | user->sock = -1; |
| 143 | _message(user->name, "** HAS QUIT **"); |
| 144 | free(user->name); |
| 145 | user->name = 0; |
| 146 | return; |
| 147 | } |
| 148 | |
| 149 | /* just a message -- send to all users */ |
| 150 | _message(user->name, line); |
| 151 | } |
| 152 | |
| 153 | static void _input(struct user_t *user, unsigned char *buffer, |
| 154 | unsigned int size) { |
| 155 | unsigned int i; |
| 156 | for (i = 0; i != size; ++i) |
| 157 | linebuffer_push(user->linebuf, sizeof(user->linebuf), &user->linepos, |
| 158 | (char)buffer[i], _online, user); |
| 159 | } |
| 160 | |
| 161 | static void _event_handler(libtelnet_t *telnet, libtelnet_event_t *ev, |
| 162 | void *user_data) { |
| 163 | struct user_t *user = (struct user_t*)user_data; |
| 164 | |
| 165 | switch (ev->type) { |
| 166 | /* data received */ |
| 167 | case LIBTELNET_EV_DATA: |
| 168 | _input(user, ev->buffer, ev->size); |
| 169 | break; |
| 170 | /* data must be sent */ |
| 171 | case LIBTELNET_EV_SEND: |
| 172 | _send(user->sock, ev->buffer, ev->size); |
| 173 | break; |
| 174 | /* error */ |
| 175 | case LIBTELNET_EV_ERROR: |
| 176 | close(user->sock); |
| 177 | user->sock = -1; |
| 178 | if (user->name != 0) { |
| 179 | _message(user->name, "** HAS HAD AN ERROR **"); |
| 180 | free(user->name); |
| 181 | user->name = 0; |
| 182 | } |
| 183 | libtelnet_free(&user->telnet); |
| 184 | break; |
| 185 | default: |
| 186 | /* ignore */ |
| 187 | break; |
| 188 | } |
| 189 | } |
| 190 | |
| 191 | int main(int argc, char **argv) { |
| 192 | unsigned char buffer[512]; |
| 193 | short listen_port; |
| 194 | int listen_sock; |
| 195 | int rs; |
| 196 | int i; |
| 197 | struct sockaddr_in addr; |
| 198 | socklen_t addrlen; |
| 199 | struct pollfd pfd[MAX_USERS + 1]; |
| 200 | |
| 201 | /* check usage */ |
| 202 | if (argc != 2) { |
| 203 | fprintf(stderr, "Usage:\n ./telnet-chatd <port>\n"); |
| 204 | return 1; |
| 205 | } |
| 206 | |
| 207 | /* initialize data structures */ |
| 208 | memset(&pfd, 0, sizeof(pfd)); |
| 209 | memset(users, 0, sizeof(users)); |
| 210 | for (i = 0; i != MAX_USERS; ++i) |
| 211 | users[i].sock = -1; |
| 212 | |
| 213 | /* parse listening port */ |
| 214 | listen_port = strtol(argv[1], 0, 10); |
| 215 | |
| 216 | /* create listening socket */ |
| 217 | if ((listen_sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) { |
| 218 | fprintf(stderr, "socket() failed: %s\n", strerror(errno)); |
| 219 | return 1; |
| 220 | } |
| 221 | |
| 222 | /* reuse address option */ |
| 223 | rs = 1; |
| 224 | setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, &rs, sizeof(rs)); |
| 225 | |
| 226 | /* bind to listening addr/port */ |
| 227 | memset(&addr, 0, sizeof(addr)); |
| 228 | addr.sin_family = AF_INET; |
| 229 | addr.sin_addr.s_addr = INADDR_ANY; |
| 230 | addr.sin_port = htons(listen_port); |
| 231 | if (bind(listen_sock, (struct sockaddr *)&addr, sizeof(addr)) == -1) { |
| 232 | fprintf(stderr, "bind() failed: %s\n", strerror(errno)); |
| 233 | return 1; |
| 234 | } |
| 235 | |
| 236 | /* listen for clients */ |
| 237 | if (listen(listen_sock, 5) == -1) { |
| 238 | fprintf(stderr, "listen() failed: %s\n", strerror(errno)); |
| 239 | return 1; |
| 240 | } |
| 241 | |
| 242 | printf("LISTENING ON PORT %d\n", listen_port); |
| 243 | |
| 244 | /* initialize listening descriptors */ |
| 245 | pfd[MAX_USERS].fd = listen_sock; |
| 246 | pfd[MAX_USERS].events = POLLIN; |
| 247 | |
| 248 | /* loop for ever */ |
| 249 | for (;;) { |
| 250 | /* prepare for poll */ |
| 251 | for (i = 0; i != MAX_USERS; ++i) { |
| 252 | if (users[i].sock != -1) { |
| 253 | pfd[i].fd = users[i].sock; |
| 254 | pfd[i].events = POLLIN; |
| 255 | } else { |
| 256 | pfd[i].fd = -1; |
| 257 | pfd[i].events = 0; |
| 258 | } |
| 259 | } |
| 260 | |
| 261 | /* poll */ |
| 262 | rs = poll(pfd, MAX_USERS + 1, -1); |
| 263 | if (rs == -1 && errno != EINTR) { |
| 264 | fprintf(stderr, "poll() failed: %s\n", strerror(errno)); |
| 265 | return 1; |
| 266 | } |
| 267 | |
| 268 | /* new connection */ |
| 269 | if (pfd[MAX_USERS].revents & POLLIN) { |
| 270 | /* acept the sock */ |
| 271 | addrlen = sizeof(addr); |
| 272 | if ((rs = accept(listen_sock, (struct sockaddr *)&addr, |
| 273 | &addrlen)) == -1) { |
| 274 | fprintf(stderr, "accept() failed: %s\n", strerror(errno)); |
| 275 | return 1; |
| 276 | } |
| 277 | |
| 278 | printf("Connection received.\n"); |
| 279 | |
| 280 | /* find a free user */ |
| 281 | for (i = 0; i != MAX_USERS; ++i) |
| 282 | if (users[i].sock == -1) |
| 283 | break; |
| 284 | if (i == MAX_USERS) { |
| 285 | printf(" rejected (too many users)\n"); |
| 286 | _send(rs, (unsigned char *)"Too many users.\r\n", 14); |
| 287 | close(rs); |
| 288 | } |
| 289 | |
| 290 | /* init, welcome */ |
| 291 | users[i].sock = rs; |
| 292 | libtelnet_init(&users[i].telnet, _event_handler, 0, &users[i]); |
| 293 | libtelnet_send_printf(&users[i].telnet, "Enter name: "); |
| 294 | } |
| 295 | |
| 296 | /* read from client */ |
| 297 | for (i = 0; i != MAX_USERS; ++i) { |
| 298 | /* skip users that aren't actually connected */ |
| 299 | if (users[i].sock == -1) |
| 300 | continue; |
| 301 | |
| 302 | if (pfd[i].revents & POLLIN) { |
| 303 | if ((rs = recv(users[i].sock, buffer, sizeof(buffer), 0)) > 0) { |
| 304 | libtelnet_push(&users[i].telnet, buffer, rs); |
| 305 | } else if (rs == 0) { |
| 306 | printf("Connection closed.\n"); |
| 307 | close(users[i].sock); |
| 308 | if (users[i].name != 0) { |
| 309 | _message(users[i].name, "** HAS DISCONNECTED **"); |
| 310 | free(users[i].name); |
| 311 | users[i].name = 0; |
| 312 | } |
| 313 | libtelnet_free(&users[i].telnet); |
| 314 | users[i].sock = -1; |
| 315 | break; |
| 316 | } else if (errno != EINTR) { |
| 317 | fprintf(stderr, "recv(client) failed: %s\n", |
| 318 | strerror(errno)); |
| 319 | exit(1); |
| 320 | } |
| 321 | } |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | /* not that we can reach this, but GCC will cry if it's not here */ |
| 326 | return 0; |
| 327 | } |