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spartserv.c (10681B)
1 /*
2 This server creates a socket listening to PORT and
3 starts the event loop
4 2 mimetypes are set depending on file extension:
5 text/gemini .gmi
6 text/markdown .md .markdown
7 */
8
9 #define _GNU_SOURCE
10 #include <string.h>
11 #include <stdio.h>
12 #include <sys/types.h>
13 #include <sys/socket.h>
14 #include <netinet/in.h>
15 #include <stdlib.h>
16 #include <unistd.h>
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <stdbool.h>
20 #include <ctype.h>
21 #include <stdarg.h>
22 #include <limits.h>
23 #include <time.h>
24 #include <fcntl.h> // access
25
26 // inet_ntoa
27 //already included #include <sys/socket.h>
28 //already included #include <netinet/in.h>
29 #include <arpa/inet.h>
30
31
32 // server configuration
33 #define HOSTNAME "localhost"
34 #define ROOT "."
35 #define PORT 3000
36
37 bool isDir(const char *path) {
38 struct stat st;
39
40 if (stat(path, &st) == -1) {
41 return(false);
42 }
43
44 if (!S_ISDIR(st.st_mode)) {
45 return(false);
46 }
47 return(true);
48 }
49
50 int main(int ac, char **av){
51 int sock;
52 struct sockaddr_in server;
53 int mysock;
54 char buf[4096];
55 int rval;
56
57 char root[PATH_MAX] = {0};
58 if (ROOT[0] == '/') {
59 realpath(ROOT, root);
60 }
61 else {
62 // create absolute path from relative ROOT path
63 char p[PATH_MAX] = {0};
64 getcwd(p, PATH_MAX);
65 strcat(p, "/");
66 strcat(p, ROOT);
67 realpath(p, root);
68 strcat(root, "/");
69 }
70
71 size_t rootLen = strlen(root);
72 size_t slash = 0;
73
74 // count slashes at the end of root
75 // to compare paths with memcmp correctly
76 // since realpath removes the slashes at the
77 // end of the path from client.
78 while(root[rootLen-1-slash] == '/') {
79 slash++;
80 }
81
82 sock = socket(AF_INET, SOCK_STREAM, 0);
83 if (sock < 0){
84 perror("Failed to create socket");
85 }
86
87 server.sin_family = AF_INET;
88 server.sin_addr.s_addr = INADDR_ANY;
89 server.sin_port = htons(PORT);
90
91 /* setsockopt: Handy debugging trick that lets
92 * us rerun the server immediately after we kill it;
93 * otherwise we have to wait about 20 secs.
94 * Eliminates "ERROR on binding: Address already in use" error.
95 */
96 int optval = 1;
97 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const void *)&optval , sizeof(int));
98
99 if (bind(sock, (struct sockaddr *) &server, sizeof(server))){
100 perror("bind failed");
101 exit(1);
102 }
103
104 listen(sock, SOMAXCONN);
105
106 printf("Serving "HOSTNAME":%d %s\n", PORT, root);
107
108 // date for request print
109 char date[50];
110 do {
111 // struct for printing client ip in terminal with inet_ntoa
112 struct sockaddr_in addr;
113 socklen_t len = sizeof(addr);
114 mysock = accept(sock, &addr, &len);
115 if (mysock == -1)
116 perror("accept failed");
117 else {
118 // Set 10s timeouts for receive and send (SO_RCVTIMEO and SO_SNDTIMEO)
119 struct timeval timeout;
120 timeout.tv_sec = 10;
121 timeout.tv_usec = 0;
122 if (setsockopt(mysock, SOL_SOCKET, SO_RCVTIMEO, (void *) &timeout, sizeof(timeout)) < 0) {
123 perror("receive timeout failed");
124 close(mysock);
125 continue;
126 }
127 if (setsockopt(mysock, SOL_SOCKET, SO_SNDTIMEO, (void *) &timeout, sizeof(timeout)) < 0) {
128 perror("send timeout failed");
129 close(mysock);
130 continue;
131 }
132
133 // new client
134 memset(buf, 0, sizeof(buf));
135 if ((rval = recv(mysock, buf, sizeof(buf), 0)) < 0) {
136 perror("reading message");
137 close(mysock);
138 continue;
139 }
140 else if (rval == 0) {
141 puts("Ending connection");
142 close(mysock);
143 continue;
144 }
145
146 // get YMD HMS date
147 time_t clk = time(NULL);
148 struct tm *pClk = localtime(&clk);
149 strftime(date, sizeof(date), "%Y-%m-%d:%H:%M:%S", pClk);
150 printf("%s %s ",date, inet_ntoa(addr.sin_addr));
151
152 // validate request then scan hostname path and content length
153
154 // find request end
155 char *reqEnd = memmem(buf, sizeof(buf), "\r\n", 2);
156 if (!reqEnd || buf[0] == ' ') {
157 puts("4 Invalid request");
158 // add MSG_NOSIGNAL flag to ignore SIGPIPE when the client closes the socket early
159 send(mysock, "4 Invalid request\r\n", sizeof("4 Invalid request\r\n"), MSG_NOSIGNAL);
160 close(mysock);
161 continue;
162 }
163
164 // check ascii
165 char *cursor = buf;
166 bool isBad = false;
167 while (cursor < reqEnd) {
168 if (*cursor < 32 || *cursor == 127) {
169 isBad = true;
170 break;
171 }
172 cursor++;
173 }
174 if (isBad) {
175 puts("4 Non ASCII");
176 send(mysock, "4 Non ASCII\r\n", sizeof("4 Non ASCII\r\n"), MSG_NOSIGNAL);
177 close(mysock);
178 continue;
179 }
180
181 // print request in terminal
182 *reqEnd = 0;
183 printf("%s ", buf);
184 *reqEnd = '\r';
185
186 // parse hostname, path and content_length in request
187 char *hostname;
188 char *path;
189 char *content_length;
190
191 hostname = buf;
192
193 // hostname must match HOSTNAME
194 // comment out this test to accept nay hostname
195 int c = memcmp(hostname, HOSTNAME, strlen(HOSTNAME));
196
197 if (c != 0) {
198 puts("4 Hostname");
199 send(mysock, "4 Hostname\r\n", sizeof("4 Hostname\r\n"), MSG_NOSIGNAL);
200 close(mysock);
201 continue;
202 }
203
204 // get path
205 cursor = buf;
206 while (*cursor != ' ' && cursor < reqEnd) {
207 cursor++;
208 }
209
210 cursor++;
211 if (cursor >= reqEnd || *cursor == ' ') {
212 puts("4 Path");
213 send(mysock, "4 Path\r\n", sizeof("4 Path\r\n"), MSG_NOSIGNAL);
214 close(mysock);
215 continue;
216 }
217
218 path = cursor;
219
220 // get content_length
221 while (*cursor != ' ' && cursor < reqEnd) {
222 cursor++;
223 }
224
225 cursor++;
226 if (cursor >= reqEnd || *cursor == ' ') {
227 puts("4 Length");
228 send(mysock, "4 Length\r\n", sizeof("4 Length\r\n"), MSG_NOSIGNAL);
229 close(mysock);
230 continue;
231 }
232
233 content_length = cursor;
234 while(cursor < reqEnd) {
235 if (!isdigit(*cursor)) {
236 isBad = true;
237 break;
238 }
239 cursor++;
240 }
241
242 // the request must not have any content
243 // content_length = 0
244 if (isBad || reqEnd - content_length > 1 || *content_length != '0') {
245 puts("4 Length");
246 send(mysock, "4 Length\r\n", sizeof("4 Length\r\n"), MSG_NOSIGNAL);
247 close(mysock);
248 continue;
249 }
250
251 // replace SPC with 0 at the end of path
252 *(content_length-1) = 0;
253
254 // build server path
255 char localPath[PATH_MAX] = {0};
256 if (rootLen + strlen(path) >= PATH_MAX) {
257 puts("5 Path too long");
258 send(mysock, "5 Path too long\r\n", sizeof("5 Path too long\r\n"), MSG_NOSIGNAL);
259 close(mysock);
260 continue;
261 }
262 memcpy(localPath, root, rootLen);
263 cursor = localPath + rootLen;
264 memcpy(cursor, path, strlen(path));
265
266 // check path
267 if (access(localPath, R_OK) == -1) {
268 puts("4 Not found");
269 send(mysock, "4 Not found\r\n", sizeof("4 Not found\r\n"), MSG_NOSIGNAL);
270 close(mysock);
271 continue;
272 }
273 char realPath[PATH_MAX] = {0};
274 realpath(localPath, realPath);
275 if (memcmp(realPath, root, rootLen-slash) != 0) {
276 puts("4 Not found");
277 send(mysock, "4 Not found\r\n", sizeof("4 Not found\r\n"), MSG_NOSIGNAL);
278 close(mysock);
279 continue;
280 }
281
282 size_t pathLen = strlen(realPath);
283 cursor = realPath + pathLen;
284 if (isDir(realPath)) {
285 if (pathLen + strlen("/index.gmi") >= PATH_MAX) {
286 puts("5 Path too long");
287 send(mysock, "5 Path too long\r\n", sizeof("5 Path too long\r\n"), MSG_NOSIGNAL);
288 close(mysock);
289 continue;
290 }
291 memcpy(cursor, "/index.gmi", strlen("/index.gmi"));
292 cursor += strlen("/index.gmi");
293 }
294
295 FILE *f = fopen(realPath, "r");
296 if (!f) {
297 puts("4 Page not found");
298 send(mysock, "4 Page not found\r\n", sizeof("4 Page not found\r\n"), MSG_NOSIGNAL);
299 close(mysock);
300 continue;
301 }
302
303 // request in buf is not needed anymore, reuse buf for response
304
305 // check gemini extension
306 char *mimetype = "application/octet-stream";
307 if (strlen(realPath) > 4 && memcmp(cursor-2, "md", 2) == 0) {
308 mimetype = "text/markdown";
309 }
310 else if (strlen(realPath) > 5 && memcmp(cursor-3, "gmi", 3) == 0) {
311 mimetype = "text/gemini";
312 }
313 else if (strlen(realPath) > 10 && memcmp(cursor-2, "markdown", 8) == 0) {
314 mimetype = "text/markdown";
315 }
316
317 int len = sprintf(buf, "2 %s\r\n", mimetype);
318 if (send(mysock, buf, len, MSG_NOSIGNAL) != -1) {
319 // print response in terminal
320 // remove \r\n
321 buf[len-2] = 0;
322 puts(buf);
323
324 // send file
325 size_t fsz;
326 while (fsz = fread(buf, 1, (size_t)sizeof(buf) , f)) {
327 ssize_t r = send(mysock, buf, fsz, MSG_NOSIGNAL);
328 if (r == -1) {
329 perror("write failed");
330 puts("closed socket");
331 break;
332 }
333 }
334 }
335 else {
336 perror("write failed");
337 }
338 fclose(f);
339 close(mysock);
340 }
341 } while(1);
342
343 puts("Server stopped.");
344 }