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spartservudp.c (10105B)
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 // TODO set HOSTNAME
34 #define HOSTNAME ""
35 //#define HOSTNAME "192.168.1.2"
36 #define ROOT "."
37 #define PORT 3000
38
39 bool isDir(const char *path) {
40 struct stat st;
41
42 if (stat(path, &st) == -1) {
43 return(false);
44 }
45
46 if (!S_ISDIR(st.st_mode)) {
47 return(false);
48 }
49 return(true);
50 }
51
52 int main(int ac, char **av){
53 int sock;
54 struct sockaddr_in server;
55 int mysock;
56 char buf[63000];
57 int rval;
58
59 char root[PATH_MAX] = {0};
60 if (ROOT[0] == '/') {
61 realpath(ROOT, root);
62 }
63 else {
64 // create absolute path from relative ROOT path
65 char p[PATH_MAX] = {0};
66 getcwd(p, PATH_MAX);
67 strcat(p, "/");
68 strcat(p, ROOT);
69 realpath(p, root);
70 strcat(root, "/");
71 }
72
73 size_t rootLen = strlen(root);
74 size_t slash = 0;
75
76 // count slashes at the end of root
77 // to compare paths with memcmp correctly
78 // since realpath removes the slashes at the
79 // end of the path from client.
80 while(root[rootLen-1-slash] == '/') {
81 slash++;
82 }
83
84 sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
85 if (sock < 0){
86 perror("Failed to create socket");
87 }
88
89 server.sin_family = AF_INET;
90 server.sin_addr.s_addr = INADDR_ANY;
91 server.sin_port = htons(PORT);
92
93 /* setsockopt: Handy debugging trick that lets
94 * us rerun the server immediately after we kill it;
95 * otherwise we have to wait about 20 secs.
96 * Eliminates "ERROR on binding: Address already in use" error.
97 */
98 int optval = 1;
99 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const void *)&optval , sizeof(int));
100
101 if (bind(sock, (struct sockaddr *) &server, sizeof(server))){
102 perror("bind failed");
103 exit(1);
104 }
105 listen(sock, SOMAXCONN);
106
107 printf("Serving "HOSTNAME":%d %s\n", PORT, root);
108
109 // date for request print
110 char date[50];
111 do {
112 // struct for printing client ip in terminal with inet_ntoa
113 struct sockaddr_in addr;
114 socklen_t len = sizeof(addr);
115 memset(buf, 0, sizeof(buf));
116 ssize_t r = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *) &addr, &len);
117 if (r == -1)
118 perror("recvfrom failed");
119 else {
120 // new client
121 // get YMD HMS date
122 time_t clk = time(NULL);
123 struct tm *pClk = localtime(&clk);
124 strftime(date, sizeof(date), "%Y-%m-%d:%H:%M:%S", pClk);
125 printf("%s %s ",date, inet_ntoa(addr.sin_addr));
126
127 int mysock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
128 if (mysock < 0){
129 perror("Failed to create socket");
130 }
131 addr.sin_port = htons(PORT);
132
133 // validate request then scan hostname path and content length
134
135 // find request end
136 char *reqEnd = memmem(buf, sizeof(buf), "\r\n", 2);
137 if (!reqEnd || buf[0] == ' ') {
138 puts("4 Invalid request");
139 // add MSG_NOSIGNAL flag to ignore SIGPIPE when the client closes the socket early
140 sendto(mysock, "4 Invalid request\r\n", sizeof("4 Invalid request\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
141 close(mysock);
142 continue;
143 }
144
145 // check ascii
146 char *cursor = buf;
147 bool isBad = false;
148 while (cursor < reqEnd) {
149 if (*cursor < 32 || *cursor == 127) {
150 isBad = true;
151 break;
152 }
153 cursor++;
154 }
155 if (isBad) {
156 puts("4 Non ASCII");
157 sendto(mysock, "4 Non ASCII\r\n", sizeof("4 Non ASCII\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
158 close(mysock);
159 continue;
160 }
161
162 // print request in terminal
163 *reqEnd = 0;
164 printf("%s ", buf);
165 *reqEnd = '\r';
166
167 // parse hostname, path and content_length in request
168 char *hostname;
169 char *path;
170 char *content_length;
171
172 hostname = buf;
173
174 // hostname must match HOSTNAME
175 // comment out this test to accept nay hostname
176 int c = memcmp(hostname, HOSTNAME, strlen(HOSTNAME));
177
178 if (c != 0) {
179 puts("4 Hostname");
180 sendto(mysock, "4 Hostname\r\n", sizeof("4 Hostname\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
181 close(mysock);
182 continue;
183 }
184
185 // get path
186 cursor = buf;
187 while (*cursor != ' ' && cursor < reqEnd) {
188 cursor++;
189 }
190
191 cursor++;
192 if (cursor >= reqEnd || *cursor == ' ') {
193 puts("4 Path");
194 sendto(mysock, "4 Path\r\n", sizeof("4 Path\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
195 close(mysock);
196 continue;
197 }
198
199 path = cursor;
200
201 // get content_length
202 while (*cursor != ' ' && cursor < reqEnd) {
203 cursor++;
204 }
205
206 cursor++;
207 if (cursor >= reqEnd || *cursor == ' ') {
208 puts("4 Length");
209 sendto(mysock, "4 Length\r\n", sizeof("4 Length\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
210 close(mysock);
211 continue;
212 }
213
214 content_length = cursor;
215 while(cursor < reqEnd) {
216 if (!isdigit(*cursor)) {
217 isBad = true;
218 break;
219 }
220 cursor++;
221 }
222
223 // the request must not have any content
224 // content_length = 0
225 if (isBad || reqEnd - content_length > 1 || *content_length != '0') {
226 puts("4 Length");
227 sendto(mysock, "4 Length\r\n", sizeof("4 Length\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
228 close(mysock);
229 continue;
230 }
231
232 // replace SPC with 0 at the end of path
233 *(content_length-1) = 0;
234
235 // build server path
236 char localPath[PATH_MAX] = {0};
237 if (rootLen + strlen(path) >= PATH_MAX) {
238 puts("5 Path too long");
239 sendto(mysock, "5 Path too long\r\n", sizeof("5 Path too long\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
240 close(mysock);
241 continue;
242 }
243 memcpy(localPath, root, rootLen);
244 cursor = localPath + rootLen;
245 memcpy(cursor, path, strlen(path));
246
247 // check path
248 if (access(localPath, R_OK) == -1) {
249 puts("4 Not found");
250 sendto(mysock, "4 Not found\r\n", sizeof("4 Not found\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
251 close(mysock);
252 continue;
253 }
254 char realPath[PATH_MAX] = {0};
255 realpath(localPath, realPath);
256 if (memcmp(realPath, root, rootLen-slash) != 0) {
257 puts("4 Not found");
258 sendto(mysock, "4 Not found\r\n", sizeof("4 Not found\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
259 close(mysock);
260 continue;
261 }
262
263 size_t pathLen = strlen(realPath);
264 cursor = realPath + pathLen;
265 if (isDir(realPath)) {
266 if (pathLen + strlen("/index.gmi") >= PATH_MAX) {
267 puts("5 Path too long");
268 sendto(mysock, "5 Path too long\r\n", sizeof("5 Path too long\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
269 close(mysock);
270 continue;
271 }
272 memcpy(cursor, "/index.gmi", strlen("/index.gmi"));
273 cursor += strlen("/index.gmi");
274 }
275
276 FILE *f = fopen(realPath, "r");
277 if (!f) {
278 puts("4 Page not found");
279 sendto(mysock, "4 Page not found\r\n", sizeof("4 Page not found\r\n"), 0, (const struct sockaddr *)&addr, sizeof(addr));
280 close(mysock);
281 continue;
282 }
283
284 // request in buf is not needed anymore, reuse buf for response
285
286 // check gemini extension
287 char *mimetype = "application/octet-stream";
288 if (strlen(realPath) > 4 && memcmp(cursor-2, "md", 2) == 0) {
289 mimetype = "text/markdown";
290 }
291 else if (strlen(realPath) > 5 && memcmp(cursor-3, "gmi", 3) == 0) {
292 mimetype = "text/gemini";
293 }
294 else if (strlen(realPath) > 10 && memcmp(cursor-2, "markdown", 8) == 0) {
295 mimetype = "text/markdown";
296 }
297
298 int len = sprintf(buf, "2 %s\r\n", mimetype);
299 // print response in terminal
300 // remove \r\n
301 buf[len-2] = 0;
302 puts(buf);
303 buf[len-2] = '\r';
304 len += fread(buf, 1, (size_t)sizeof(buf) , f);
305 if (sendto(mysock, buf, len, 0, (const struct sockaddr *)&addr, sizeof(addr)) == -1) {
306 perror("write failed");
307 }
308 fclose(f);
309 close(mysock);
310 }
311 } while(1);
312
313 puts("Server stopped.");
314 }