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c988f1f4 | 1 | /* $Cambridge: exim/src/src/header.c,v 1.4 2005/01/04 10:00:42 ph10 Exp $ */ |
059ec3d9 PH |
2 | |
3 | /************************************************* | |
4 | * Exim - an Internet mail transport agent * | |
5 | *************************************************/ | |
6 | ||
c988f1f4 | 7 | /* Copyright (c) University of Cambridge 1995 - 2005 */ |
059ec3d9 PH |
8 | /* See the file NOTICE for conditions of use and distribution. */ |
9 | ||
10 | ||
11 | #include "exim.h" | |
12 | ||
13 | ||
14 | /************************************************* | |
15 | * Test a header for matching name * | |
16 | *************************************************/ | |
17 | ||
18 | /* This function tests the name of a header. It is made into a function because | |
19 | it isn't just a string comparison: spaces and tabs are permitted between the | |
20 | name and the colon. The h->text field should nowadays never be NULL, but check | |
21 | it just in case. | |
22 | ||
23 | Arguments: | |
24 | h points to the header | |
25 | name the name to test | |
26 | len the length of the name | |
27 | notdel if TRUE, force FALSE for deleted headers | |
28 | ||
29 | Returns: TRUE or FALSE | |
30 | */ | |
31 | ||
32 | BOOL | |
33 | header_testname(header_line *h, uschar *name, int len, BOOL notdel) | |
34 | { | |
35 | uschar *tt; | |
36 | if (h->type == '*' && notdel) return FALSE; | |
37 | if (h->text == NULL || strncmpic(h->text, name, len) != 0) return FALSE; | |
38 | tt = h->text + len; | |
39 | while (*tt == ' ' || *tt == '\t') tt++; | |
40 | return *tt == ':'; | |
41 | } | |
42 | ||
8523533c TK |
43 | /* This is a copy of the function above, only that it is possible to pass |
44 | only the beginning of a header name. It simply does a front-anchored | |
45 | substring match. Arguments and Return codes are the same as for | |
46 | header_testname() above. */ | |
47 | ||
48 | BOOL | |
49 | header_testname_incomplete(header_line *h, uschar *name, int len, BOOL notdel) | |
50 | { | |
8523533c TK |
51 | if (h->type == '*' && notdel) return FALSE; |
52 | if (h->text == NULL || strncmpic(h->text, name, len) != 0) return FALSE; | |
53 | return TRUE; | |
54 | } | |
059ec3d9 PH |
55 | |
56 | ||
57 | /************************************************* | |
58 | * Add new header backend function * | |
59 | *************************************************/ | |
60 | ||
61 | /* The header_last variable points to the last header during message reception | |
62 | and delivery; otherwise it is NULL. We add new headers only when header_last is | |
63 | not NULL. The function may get called sometimes when it is NULL (e.g. during | |
64 | address verification where rewriting options exist). When called from a filter, | |
65 | there may be multiple header lines in a single string. | |
66 | ||
67 | This is an internal static function that is the common back end to the external | |
68 | functions defined below. The general interface allows the header to be inserted | |
69 | before or after a given occurrence of a given header. | |
70 | ||
71 | (a) if "name" is NULL, the header is added at the end of all the existing | |
72 | headers if "after" is true, or at the start if it is false. The "topnot" | |
73 | flag is not used. | |
74 | ||
75 | (b) If "name" is not NULL, the first existing header with that name is sought. | |
76 | If "after" is false, the new header is added before it. If "after" is true, | |
77 | a check is made for adjacent headers with the same name, and the new header | |
78 | is added after the last of them. If a header of the given name is not | |
79 | found, the new header is added first if "topnot" is true, and at the bottom | |
80 | otherwise. | |
81 | ||
82 | Arguments: | |
83 | after TRUE for "after", FALSE for "before" | |
84 | name name if adding at a specific header, else NULL | |
85 | topnot TRUE to add at top if no header found | |
86 | type Exim header type character (htype_something) | |
87 | format sprintf format | |
88 | ap va_list value for format arguments | |
89 | ||
90 | Returns: nothing | |
91 | */ | |
92 | ||
93 | static void | |
94 | header_add_backend(BOOL after, uschar *name, BOOL topnot, int type, | |
95 | char *format, va_list ap) | |
96 | { | |
97 | header_line *h, *new; | |
98 | header_line **hptr; | |
99 | ||
100 | uschar *p, *q; | |
101 | uschar buffer[HEADER_ADD_BUFFER_SIZE]; | |
102 | ||
103 | if (header_last == NULL) return; | |
104 | ||
105 | if (!string_vformat(buffer, sizeof(buffer), format, ap)) | |
106 | log_write(0, LOG_MAIN|LOG_PANIC_DIE, "string too long in header_add: " | |
107 | "%.100s ...", buffer); | |
108 | ||
109 | /* Find where to insert this header */ | |
110 | ||
111 | if (name == NULL) | |
112 | { | |
113 | if (after) | |
114 | { | |
115 | hptr = &(header_last->next); | |
116 | h = NULL; | |
117 | } | |
118 | else | |
119 | { | |
120 | hptr = &header_list; | |
121 | h = header_list; | |
122 | } | |
123 | } | |
124 | ||
125 | else | |
126 | { | |
127 | int len = Ustrlen(name); | |
128 | ||
129 | /* Find the first non-deleted header witht the correct name. */ | |
130 | ||
131 | for (hptr = &header_list; (h = *hptr) != NULL; hptr = &(h->next)) | |
132 | { | |
133 | if (header_testname(h, name, len, TRUE)) break; | |
134 | } | |
135 | ||
136 | /* Handle the case where no header is found. To insert at the bottom, nothing | |
137 | needs to be done. */ | |
138 | ||
139 | if (h == NULL) | |
140 | { | |
141 | if (topnot) | |
142 | { | |
143 | hptr = &header_list; | |
144 | h = header_list; | |
145 | } | |
146 | } | |
147 | ||
148 | /* Handle the case where a header is found. Check for more if "after" is | |
149 | true. In this case, we want to include deleted headers in the block. */ | |
150 | ||
151 | else if (after) | |
152 | { | |
153 | for (;;) | |
154 | { | |
155 | if (h->next == NULL || !header_testname(h, name, len, FALSE)) break; | |
156 | hptr = &(h->next); | |
157 | h = h->next; | |
158 | } | |
159 | } | |
160 | } | |
161 | ||
162 | /* Loop for multiple header lines, taking care about continuations. At this | |
163 | point, we have hptr pointing to the link field that will point to the new | |
164 | header, and h containing the following header, or NULL. */ | |
165 | ||
166 | for (p = q = buffer; *p != 0; ) | |
167 | { | |
168 | for (;;) | |
169 | { | |
170 | q = Ustrchr(q, '\n'); | |
171 | if (q == NULL) q = p + Ustrlen(p); | |
172 | if (*(++q) != ' ' && *q != '\t') break; | |
173 | } | |
174 | ||
175 | new = store_get(sizeof(header_line)); | |
176 | new->text = string_copyn(p, q - p); | |
177 | new->slen = q - p; | |
178 | new->type = type; | |
179 | new->next = h; | |
180 | ||
181 | *hptr = new; | |
182 | hptr = &(new->next); | |
183 | ||
184 | if (h == NULL) header_last = new; | |
185 | p = q; | |
186 | } | |
187 | } | |
188 | ||
189 | ||
190 | /************************************************* | |
191 | * Add new header anywhere in the chain * | |
192 | *************************************************/ | |
193 | ||
194 | /* This is an external interface to header_add_backend(). | |
195 | ||
196 | Arguments: | |
197 | after TRUE for "after", FALSE for "before" | |
198 | name name if adding at a specific header, else NULL | |
199 | topnot TRUE to add at top if no header found | |
200 | type Exim header type character (htype_something) | |
201 | format sprintf format | |
202 | ... format arguments | |
203 | ||
204 | Returns: nothing | |
205 | */ | |
206 | ||
207 | void | |
208 | header_add_at_position(BOOL after, uschar *name, BOOL topnot, int type, | |
209 | char *format, ...) | |
210 | { | |
211 | va_list ap; | |
212 | va_start(ap, format); | |
213 | header_add_backend(after, name, topnot, type, format, ap); | |
214 | va_end(ap); | |
215 | } | |
216 | ||
217 | ||
218 | ||
219 | /************************************************* | |
220 | * Add new header on end of chain * | |
221 | *************************************************/ | |
222 | ||
223 | /* This is now a convenience interface to header_add_backend(). | |
224 | ||
225 | Arguments: | |
226 | type Exim header type character | |
227 | format sprintf format | |
228 | ... arguments for the format | |
229 | ||
230 | Returns: nothing | |
231 | */ | |
232 | ||
233 | void | |
234 | header_add(int type, char *format, ...) | |
235 | { | |
236 | va_list ap; | |
237 | va_start(ap, format); | |
238 | header_add_backend(TRUE, NULL, FALSE, type, format, ap); | |
239 | va_end(ap); | |
240 | } | |
241 | ||
242 | ||
243 | ||
244 | /************************************************* | |
245 | * Remove (mark as old) a header * | |
246 | *************************************************/ | |
247 | ||
248 | /* This function is used by the filter code; it is also exported in the | |
249 | local_scan() API. If no header is found, the function does nothing. | |
250 | ||
251 | Arguments: | |
252 | occ the occurrence number for multiply-defined headers | |
253 | <= 0 means "all"; deleted headers are not counted | |
254 | name the header name | |
255 | ||
256 | Returns: nothing | |
257 | */ | |
258 | ||
259 | void | |
260 | header_remove(int occ, uschar *name) | |
261 | { | |
262 | header_line *h; | |
263 | int hcount = 0; | |
264 | int len = Ustrlen(name); | |
265 | for (h = header_list; h != NULL; h = h->next) | |
266 | { | |
267 | if (header_testname(h, name, len, TRUE) && (occ <= 0 || ++hcount == occ)) | |
268 | { | |
269 | h->type = htype_old; | |
270 | if (occ > 0) return; | |
271 | } | |
272 | } | |
273 | } | |
274 | ||
275 | ||
276 | ||
277 | /************************************************* | |
278 | * Check the name of a header * | |
279 | *************************************************/ | |
280 | ||
281 | /* This function scans a table of header field names that Exim recognizes, and | |
282 | returns the identification of a match. If "resent" is true, the header is known | |
283 | to start with "resent-". In that case, the function matches only those fields | |
284 | that are allowed to appear with resent- in front of them. | |
285 | ||
286 | Arguments: | |
287 | h points to the header line | |
288 | is_resent TRUE if the name starts "Resent-" | |
289 | ||
290 | Returns: One of the htype_ enum values, identifying the header | |
291 | */ | |
292 | ||
293 | int | |
294 | header_checkname(header_line *h, BOOL is_resent) | |
295 | { | |
296 | uschar *text = h->text; | |
297 | header_name *bot = header_names; | |
298 | header_name *top = header_names + header_names_size; | |
299 | ||
300 | if (is_resent) text += 7; | |
301 | ||
302 | while (bot < top) | |
303 | { | |
304 | header_name *mid = bot + (top - bot)/2; | |
305 | int c = strncmpic(text, mid->name, mid->len); | |
306 | ||
307 | if (c == 0) | |
308 | { | |
309 | uschar *s = text + mid->len; | |
310 | while (isspace(*s)) s++; | |
311 | if (*s == ':') | |
312 | return (!is_resent || mid->allow_resent)? mid->htype : htype_other; | |
313 | c = 1; | |
314 | } | |
315 | ||
316 | if (c > 0) bot = mid + 1; else top = mid; | |
317 | } | |
318 | ||
319 | return htype_other; | |
320 | } | |
321 | ||
322 | ||
323 | /************************************************* | |
324 | * Scan a header for certain strings * | |
325 | *************************************************/ | |
326 | ||
327 | /* This function is used for the "personal" test. It scans a particular header | |
328 | line for any one of a number of strings, matched caselessly either as plain | |
329 | strings, or as regular expressions. If the header line contains a list of | |
330 | addresses, each match is applied only to the operative part of each address in | |
331 | the header, and non-regular expressions must be exact matches. | |
332 | ||
333 | The patterns can be provided either as a chain of string_item structures, or | |
334 | inline in the argument list, or both. If there is more than one header of the | |
335 | same name, they are all searched. | |
336 | ||
337 | Arguments: | |
338 | name header name, including the trailing colon | |
339 | has_addresses TRUE if the header contains a list of addresses | |
340 | cond value to return if the header contains any of the strings | |
341 | strings points to a chain of string_item blocks | |
342 | count number of inline strings | |
343 | ... the inline strings | |
344 | ||
345 | Returns: cond if the header exists and contains one of the strings; | |
346 | otherwise !cond | |
347 | */ | |
348 | ||
349 | ||
350 | /* First we have a local subroutine to handle a single pattern */ | |
351 | ||
352 | static BOOL | |
353 | one_pattern_match(uschar *name, int slen, BOOL has_addresses, uschar *pattern) | |
354 | { | |
355 | BOOL yield = FALSE; | |
356 | header_line *h; | |
357 | const pcre *re = NULL; | |
358 | ||
359 | /* If the pattern is a regex, compile it. Bomb out if compiling fails; these | |
360 | patterns are all constructed internally and should be valid. */ | |
361 | ||
362 | if (*pattern == '^') re = regex_must_compile(pattern, TRUE, FALSE); | |
363 | ||
364 | /* Scan for the required header(s) and scan each one */ | |
365 | ||
366 | for (h = header_list; !yield && h != NULL; h = h->next) | |
367 | { | |
368 | if (h->type == htype_old || slen > h->slen || | |
369 | strncmpic(name, h->text, slen) != 0) | |
370 | continue; | |
371 | ||
372 | /* If the header is a list of addresses, extract each one in turn, and scan | |
373 | it. A non-regex scan must be an exact match for the address. */ | |
374 | ||
375 | if (has_addresses) | |
376 | { | |
377 | uschar *s = h->text + slen; | |
378 | ||
379 | while (!yield && *s != 0) | |
380 | { | |
381 | uschar *error, *next; | |
382 | uschar *e = parse_find_address_end(s, FALSE); | |
383 | int terminator = *e; | |
384 | int start, end, domain; | |
385 | ||
386 | /* Temporarily terminate the string at the address end while extracting | |
387 | the operative address within. */ | |
388 | ||
389 | *e = 0; | |
390 | next = parse_extract_address(s, &error, &start, &end, &domain, FALSE); | |
391 | *e = terminator; | |
392 | ||
393 | /* Move on, ready for the next address */ | |
394 | ||
395 | s = e; | |
396 | if (*s == ',') s++; | |
397 | ||
398 | /* If there is some kind of syntax error, just give up on this header | |
399 | line. */ | |
400 | ||
401 | if (next == NULL) break; | |
402 | ||
403 | /* Otherwise, test for the pattern; a non-regex must be an exact match */ | |
404 | ||
405 | yield = (re == NULL)? | |
406 | (strcmpic(next, pattern) == 0) | |
407 | : | |
408 | (pcre_exec(re, NULL, CS next, Ustrlen(next), 0, PCRE_EOPT, NULL, 0) | |
409 | >= 0); | |
410 | } | |
411 | } | |
412 | ||
413 | /* For headers that are not lists of addresses, scan the entire header line, | |
414 | and just require "contains" for non-regex patterns. */ | |
415 | ||
416 | else | |
417 | { | |
418 | yield = (re == NULL)? | |
419 | (strstric(h->text, pattern, FALSE) != NULL) | |
420 | : | |
421 | (pcre_exec(re, NULL, CS h->text, h->slen, 0, PCRE_EOPT, NULL, 0) >= 0); | |
422 | } | |
423 | } | |
424 | ||
425 | return yield; | |
426 | } | |
427 | ||
428 | ||
429 | /* The externally visible interface */ | |
430 | ||
431 | BOOL | |
432 | header_match(uschar *name, BOOL has_addresses, BOOL cond, string_item *strings, | |
433 | int count, ...) | |
434 | { | |
435 | va_list ap; | |
436 | string_item *s; | |
437 | int i; | |
438 | int slen = Ustrlen(name); | |
439 | ||
440 | for (s = strings; s != NULL; s = s->next) | |
441 | { | |
442 | if (one_pattern_match(name, slen, has_addresses, s->text)) return cond; | |
443 | } | |
444 | ||
445 | va_start(ap, count); | |
446 | for (i = 0; i < count; i++) | |
447 | { | |
448 | if (one_pattern_match(name, slen, has_addresses, va_arg(ap, uschar *))) | |
449 | return cond; | |
450 | } | |
451 | va_end(ap); | |
452 | ||
453 | return !cond; | |
454 | } | |
455 | ||
456 | /* End of header.c */ |