ae60d72b7b7501751078d340bf2d285d9981ca75
[samba.git] / source / web / cgi.c
1 /* 
2    some simple CGI helper routines
3    Copyright (C) Andrew Tridgell 1997-1998
4    
5    This program is free software; you can redistribute it and/or modify
6    it under the terms of the GNU General Public License as published by
7    the Free Software Foundation; either version 2 of the License, or
8    (at your option) any later version.
9    
10    This program is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13    GNU General Public License for more details.
14    
15    You should have received a copy of the GNU General Public License
16    along with this program; if not, write to the Free Software
17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19
20
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <sys/stat.h>
24 #include <string.h>
25 #include <fcntl.h>
26 #include <unistd.h>
27 #include <pwd.h>
28
29 #define MAX_VARIABLES 10000
30
31 #ifdef DEBUG_COMMENTS
32 extern void print_title(char *fmt, ...);
33 #endif
34
35 struct var {
36         char *name;
37         char *value;
38 };
39
40 static struct var variables[MAX_VARIABLES];
41 static int num_variables;
42 static int content_length;
43 static int request_post;
44 static int request_get;
45 static char *query_string;
46
47 static void unescape(char *buf)
48 {
49         char *p=buf;
50
51         while ((p=strchr(p,'+')))
52                 *p = ' ';
53
54         p = buf;
55
56         while (p && *p && (p=strchr(p,'%'))) {
57                 int c1 = p[1];
58                 int c2 = p[2];
59
60                 if (c1 >= '0' && c1 <= '9')
61                         c1 = c1 - '0';
62                 else if (c1 >= 'A' && c1 <= 'F')
63                         c1 = 10 + c1 - 'A';
64                 else if (c1 >= 'a' && c1 <= 'f')
65                         c1 = 10 + c1 - 'a';
66                 else {p++; continue;}
67
68                 if (c2 >= '0' && c2 <= '9')
69                         c2 = c2 - '0';
70                 else if (c2 >= 'A' && c2 <= 'F')
71                         c2 = 10 + c2 - 'A';
72                 else if (c2 >= 'a' && c2 <= 'f')
73                         c2 = 10 + c2 - 'a';
74                 else {p++; continue;}
75                         
76                 *p = (c1<<4) | c2;
77
78                 memcpy(p+1, p+3, strlen(p+3)+1);
79                 p++;
80         }
81 }
82
83
84 static char *grab_line(FILE *f, int *cl)
85 {
86         char *ret;
87         int i = 0;
88         int len = 1024;
89
90         ret = (char *)malloc(len);
91         if (!ret) return NULL;
92         
93
94         while ((*cl)) {
95                 int c = fgetc(f);
96                 (*cl)--;
97
98                 if (c == EOF) {
99                         (*cl) = 0;
100                         break;
101                 }
102                 
103                 if (c == '\r') continue;
104
105                 if (strchr("\n&", c)) break;
106
107                 ret[i++] = c;
108
109                 if (i == len-1) {
110                         char *ret2;
111                         ret2 = (char *)realloc(ret, len*2);
112                         if (!ret2) return ret;
113                         len *= 2;
114                         ret = ret2;
115                 }
116         }
117         
118
119         ret[i] = 0;
120         return ret;
121 }
122
123 /***************************************************************************
124   load all the variables passed to the CGI program. May have multiple variables
125   with the same name and the same or different values. Takes a file parameter
126   for simulating CGI invocation eg loading saved preferences.
127   ***************************************************************************/
128 void cgi_load_variables(FILE *f1)
129 {
130         FILE *f = f1;
131         static char *line;
132         char *p, *s, *tok;
133         int len;
134
135 #ifdef DEBUG_COMMENTS
136         char dummy[100]="";
137         print_title(dummy);
138         printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
139 #endif
140
141         if (!f1) {
142                 f = stdin;
143                 if (!content_length) {
144                         p = getenv("CONTENT_LENGTH");
145                         len = p?atoi(p):0;
146                 } else {
147                         len = content_length;
148                 }
149         } else {
150                 fseek(f, 0, SEEK_END);
151                 len = ftell(f);
152                 fseek(f, 0, SEEK_SET);
153         }
154
155
156         if (len > 0 && 
157             (f1 || request_post ||
158              ((s=getenv("REQUEST_METHOD")) && 
159               strcasecmp(s,"POST")==0))) {
160                 while (len && (line=grab_line(f, &len))) {
161                         p = strchr(line,'=');
162                         if (!p) continue;
163                         
164                         *p = 0;
165                         
166                         variables[num_variables].name = strdup(line);
167                         variables[num_variables].value = strdup(p+1);
168
169                         free(line);
170                         
171                         if (!variables[num_variables].name || 
172                             !variables[num_variables].value)
173                                 continue;
174
175                         unescape(variables[num_variables].value);
176                         unescape(variables[num_variables].name);
177
178 #ifdef DEBUG_COMMENTS
179                         printf("<!== POST var %s has value \"%s\"  ==>\n",
180                                variables[num_variables].name,
181                                variables[num_variables].value);
182 #endif
183                         
184                         num_variables++;
185                         if (num_variables == MAX_VARIABLES) break;
186                 }
187         }
188
189         if (f1) {
190 #ifdef DEBUG_COMMENTS
191                 printf("<!== End dump in cgi_load_variables() ==>\n"); 
192 #endif
193                 return;
194         }
195
196         fclose(stdin);
197
198         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
199                 for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
200                         p = strchr(tok,'=');
201                         if (!p) continue;
202                         
203                         *p = 0;
204                         
205                         variables[num_variables].name = strdup(tok);
206                         variables[num_variables].value = strdup(p+1);
207
208                         if (!variables[num_variables].name || 
209                             !variables[num_variables].value)
210                                 continue;
211
212                         unescape(variables[num_variables].value);
213                         unescape(variables[num_variables].name);
214
215 #ifdef DEBUG_COMMENTS
216                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
217                                variables[num_variables].name,
218                                variables[num_variables].value);
219 #endif                                          
220                         num_variables++;
221                         if (num_variables == MAX_VARIABLES) break;
222                 }
223
224         }
225 #ifdef DEBUG_COMMENTS
226         printf("<!== End dump in cgi_load_variables() ==>\n");   
227 #endif
228 }
229
230
231 /***************************************************************************
232   find a variable passed via CGI
233   Doesn't quite do what you think in the case of POST text variables, because
234   if they exist they might have a value of "" or even " ", depending on the 
235   browser. Also doesn't allow for variables[] containing multiple variables
236   with the same name and the same or different values.
237   ***************************************************************************/
238 char *cgi_variable(char *name)
239 {
240         int i;
241
242         for (i=0;i<num_variables;i++)
243                 if (strcmp(variables[i].name, name) == 0)
244                         return variables[i].value;
245         return NULL;
246 }
247
248 /***************************************************************************
249 return a particular cgi variable
250   ***************************************************************************/
251 char *cgi_vnum(int i, char **name)
252 {
253         if (i < 0 || i >= num_variables) return NULL;
254         *name = variables[i].name;
255         return variables[i].value;
256 }
257
258 /***************************************************************************
259   return the value of a CGI boolean variable.
260   ***************************************************************************/
261 int cgi_boolean(char *name, int def)
262 {
263         char *p = cgi_variable(name);
264
265         if (!p) return def;
266
267         return strcmp(p, "1") == 0;
268 }
269
270 /***************************************************************************
271 like strdup() but quotes < > and &
272   ***************************************************************************/
273 char *quotedup(char *s)
274 {
275         int i, n=0;
276         int len;
277         char *ret;
278         char *d;
279
280         if (!s) return strdup("");
281
282         len = strlen(s);
283
284         for (i=0;i<len;i++)
285                 if (s[i] == '<' || s[i] == '>' || s[i] == '&')
286                         n++;
287
288         ret = malloc(len + n*6 + 1);
289
290         if (!ret) return NULL;
291
292         d = ret;
293
294         for (i=0;i<len;i++) {
295                 switch (s[i]) {
296                 case '<':
297                         strcpy(d, "&lt;");
298                         d += 4;
299                         break;
300
301                 case '>':
302                         strcpy(d, "&gt;");
303                         d += 4;
304                         break;
305
306                 case '&':
307                         strcpy(d, "&amp;");
308                         d += 5;
309                         break;
310
311                 default:
312                         *d++ = s[i];
313                 }
314         }
315
316         *d = 0;
317
318         return ret;
319 }
320
321
322 /***************************************************************************
323 like strdup() but quotes a wide range of characters
324   ***************************************************************************/
325 char *urlquote(char *s)
326 {
327         int i, n=0;
328         int len;
329         char *ret;
330         char *d;
331         char *qlist = "\"\n\r'&<> \t+;";
332
333         if (!s) return strdup("");
334
335         len = strlen(s);
336
337         for (i=0;i<len;i++)
338                 if (strchr(qlist, s[i])) n++;
339
340         ret = malloc(len + n*2 + 1);
341
342         if (!ret) return NULL;
343
344         d = ret;
345
346         for (i=0;i<len;i++) {
347                 if (strchr(qlist,s[i])) {
348                         sprintf(d, "%%%02X", (int)s[i]);
349                         d += 3;
350                 } else {
351                         *d++ = s[i];
352                 }
353         }
354
355         *d = 0;
356
357         return ret;
358 }
359
360
361 /***************************************************************************
362 like strdup() but quotes " characters
363   ***************************************************************************/
364 char *quotequotes(char *s)
365 {
366         int i, n=0;
367         int len;
368         char *ret;
369         char *d;
370
371         if (!s) return strdup("");
372
373         len = strlen(s);
374
375         for (i=0;i<len;i++)
376                 if (s[i] == '"')
377                         n++;
378
379         ret = malloc(len + n*6 + 1);
380
381         if (!ret) return NULL;
382
383         d = ret;
384
385         for (i=0;i<len;i++) {
386                 switch (s[i]) {
387                 case '"':
388                         strcpy(d, "&quot;");
389                         d += 6;
390                         break;
391
392                 default:
393                         *d++ = s[i];
394                 }
395         }
396
397         *d = 0;
398
399         return ret;
400 }
401
402
403 /***************************************************************************
404 quote spaces in a buffer
405   ***************************************************************************/
406 void quote_spaces(char *buf)
407 {
408         while (*buf) {
409                 if (*buf == ' ') *buf = '+';
410                 buf++;
411         }
412 }
413
414
415
416 /***************************************************************************
417 tell a browser about a fatal error in the http processing
418   ***************************************************************************/
419 static void cgi_setup_error(char *err, char *header, char *info)
420 {
421         printf("HTTP/1.1 %s\r\n%sConnection: close\r\nContent-Type: text/html\r\n\r\n<HTML><HEAD><TITLE>%s</TITLE></HEAD><BODY><H1>%s</H1>%s<p></BODY></HTML>\r\n", err, header, err, err, info);
422         exit(0);
423 }
424
425
426 /***************************************************************************
427 decode a base64 string in-place - simple and slow algorithm
428   ***************************************************************************/
429 static void base64_decode(char *s)
430 {
431         char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
432         int bit_offset, byte_offset, idx, i;
433         unsigned char *d = (unsigned char *)s;
434         char *p;
435
436         i=0;
437
438         while (*s && (p=strchr(b64,*s))) {
439                 idx = (int)(p - b64);
440                 byte_offset = (i*6)/8;
441                 bit_offset = (i*6)%8;
442                 d[byte_offset] &= ~((1<<(8-bit_offset))-1);
443                 if (bit_offset < 3) {
444                         d[byte_offset] |= (idx << (2-bit_offset));
445                 } else {
446                         d[byte_offset] |= (idx >> (bit_offset-2));
447                         d[byte_offset+1] = 0;
448                         d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF;
449                 }
450                 s++; i++;
451         }
452 }
453
454
455 /***************************************************************************
456 handle a http authentication line
457   ***************************************************************************/
458 static int cgi_handle_authorization(char *line)
459 {
460         char *p, *user, *pass;
461         struct passwd *pwd;
462         int ret=0;
463
464         if (strncasecmp(line,"Basic ", 6)) {
465                 cgi_setup_error("401 Bad Authorization", "", 
466                                 "Only basic authorization is understood");
467         }
468         line += 6;
469         while (line[0] == ' ') line++;
470         base64_decode(line);
471         if (!(p=strchr(line,':'))) {
472                 cgi_setup_error("401 Bad Authorization", "", 
473                                 "username/password must be supplied");
474         }
475         *p = 0;
476         user = line;
477         pass = p+1;
478
479         /* currently only allow connections as root */
480         if (strcasecmp(user,"root")) {
481                 cgi_setup_error("401 Bad Authorization", "", 
482                                 "incorrect username/password");
483         }
484         
485         pwd = getpwnam(user);
486
487         if (!strcmp((char *)crypt(pass, pwd->pw_passwd),pwd->pw_passwd)) {
488                 ret = 1;
489         }
490
491         memset(pass, 0, strlen(pass));
492
493         return ret;
494 }
495
496
497 /***************************************************************************
498 handle a file download
499   ***************************************************************************/
500 static void cgi_download(char *file)
501 {
502         struct stat st;
503         char buf[1024];
504         int fd, l, i;
505         char *p;
506
507         /* sanitise the filename */
508         for (i=0;file[i];i++) {
509                 if (!isalnum(file[i]) && !strchr("/.-_", file[i])) {
510                         cgi_setup_error("404 File Not Found","",
511                                         "Illegal character in filename");
512                 }
513         }
514
515         if (strstr(file,"..")) {
516                 cgi_setup_error("404 File Not Found","",
517                                 "Relative paths not allowed");
518         }
519
520         if (!file_exist(file, &st)) {
521                 cgi_setup_error("404 File Not Found","",
522                                 "The requested file was not found");
523         }
524         fd = open(file,O_RDONLY);
525         if (fd == -1) {
526                 cgi_setup_error("404 File Not Found","",
527                                 "The requested file was not found");
528         }
529         printf("HTTP/1.1 200 OK\r\n");
530         if ((p=strrchr(file,'.'))) {
531                 if (strcmp(p,".gif")==0 || strcmp(p,".jpg")==0) {
532                         printf("Content-Type: image/gif\r\n");
533                 } else {
534                         printf("Content-Type: text/html\r\n");
535                 }
536         }
537         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
538         while ((l=read(fd,buf,sizeof(buf)))>0) {
539                 fwrite(buf, 1, l, stdout);
540         }
541         close(fd);
542         exit(0);
543 }
544
545
546 /***************************************************************************
547 setup the cgi framework, handling the possability that this program is either
548 run as a true cgi program by a web browser or is itself a mini web server
549   ***************************************************************************/
550 void cgi_setup(char *rootdir)
551 {
552         int authenticated = 0;
553         char line[1024];
554         char *url=NULL;
555         char *p;
556
557         if (chdir(rootdir)) {
558                 cgi_setup_error("400 Server Error", "",
559                                 "chdir failed - the server is not configured correctly");
560         }
561
562         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
563                 /* assume we are running under a real web server */
564                 return;
565         }
566
567         /* we are a mini-web server. We need to read the request from stdin
568            and handle authentication etc */
569         while (fgets(line, sizeof(line)-1, stdin)) {
570                 if (line[0] == '\r' || line[0] == '\n') break;
571                 if (strncasecmp(line,"GET ", 4)==0) {
572                         request_get = 1;
573                         url = strdup(&line[4]);
574                 } else if (strncasecmp(line,"POST ", 5)==0) {
575                         request_post = 1;
576                         url = strdup(&line[5]);
577                 } else if (strncasecmp(line,"PUT ", 4)==0) {
578                         cgi_setup_error("400 Bad Request", "",
579                                         "This server does not accept PUT requests");
580                 } else if (strncasecmp(line,"Authorization: ", 15)==0) {
581                         authenticated = cgi_handle_authorization(&line[15]);
582                 } else if (strncasecmp(line,"Content-Length: ", 16)==0) {
583                         content_length = atoi(&line[16]);
584                 }
585                 /* ignore all other requests! */
586         }
587
588         if (!authenticated) {
589                 cgi_setup_error("401 Authorization Required", 
590                                 "WWW-Authenticate: Basic realm=\"root\"\r\n",
591                                 "You must be authenticated to use this service");
592         }
593
594         if (!url) {
595                 cgi_setup_error("400 Bad Request", "",
596                                 "You must specify a GET or POST request");
597         }
598
599         /* trim the URL */
600         if ((p = strchr(url,' ')) || (p=strchr(url,'\t'))) {
601                 *p = 0;
602         }
603         while (*url && strchr("\r\n",url[strlen(url)-1])) {
604                 url[strlen(url)-1] = 0;
605         }
606
607         /* anything following a ? in the URL is part of the query string */
608         if ((p=strchr(url,'?'))) {
609                 query_string = p+1;
610                 *p = 0;
611         }
612
613         if (strcmp(url,"/")) {
614                 cgi_download(url+1);
615         }
616
617         printf("HTTP/1.1 200 OK\r\nConnection: close\r\n");
618         
619 }
620
621