aboutsummaryrefslogtreecommitdiff
path: root/filter.c
blob: c7037a30ab82c4901b616dd056de94997a071f46 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
/* filter.c: filter framework functions
 *
 * Copyright (C) 2006-2014 cgit Development Team <cgit@lists.zx2c4.com>
 *
 * Licensed under GNU General Public License v2
 *   (see COPYING for full license text)
 */

#include "cgit.h"
#include "html.h"
#include <dlfcn.h>
#ifndef NO_LUA
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
#endif

static ssize_t (*libc_write)(int fd, const void *buf, size_t count);
static ssize_t (*filter_write)(struct cgit_filter *base, const void *buf, size_t count) = NULL;
static struct cgit_filter *current_write_filter = NULL;

static inline void reap_filter(struct cgit_filter *filter)
{
	if (filter && filter->cleanup)
		filter->cleanup(filter);
}

void cgit_cleanup_filters(void)
{
	int i;
	reap_filter(ctx.cfg.about_filter);
	reap_filter(ctx.cfg.commit_filter);
	reap_filter(ctx.cfg.source_filter);
	reap_filter(ctx.cfg.email_filter);
	reap_filter(ctx.cfg.owner_filter);
	reap_filter(ctx.cfg.auth_filter);
	for (i = 0; i < cgit_repolist.count; ++i) {
		reap_filter(cgit_repolist.repos[i].about_filter);
		reap_filter(cgit_repolist.repos[i].commit_filter);
		reap_filter(cgit_repolist.repos[i].source_filter);
		reap_filter(cgit_repolist.repos[i].email_filter);
		reap_filter(cgit_repolist.repos[i].owner_filter);
	}
}

void cgit_init_filters(void)
{
	libc_write = dlsym(RTLD_NEXT, "write");
	if (!libc_write)
		die("Could not locate libc's write function");
}

ssize_t write(int fd, const void *buf, size_t count)
{
	if (fd != STDOUT_FILENO || !filter_write)
		return libc_write(fd, buf, count);
	return filter_write(current_write_filter, buf, count);
}

static inline void hook_write(struct cgit_filter *filter, ssize_t (*new_write)(struct cgit_filter *base, const void *buf, size_t count))
{
	/* We want to avoid buggy nested patterns. */
	assert(filter_write == NULL);
	assert(current_write_filter == NULL);
	current_write_filter = filter;
	filter_write = new_write;
}

static inline void unhook_write(void)
{
	assert(filter_write != NULL);
	assert(current_write_filter != NULL);
	filter_write = NULL;
	current_write_filter = NULL;
}

static int open_exec_filter(struct cgit_filter *base, va_list ap)
{
	struct cgit_exec_filter *filter = (struct cgit_exec_filter *)base;
	int i;

	for (i = 0; i < filter->base.argument_count; i++)
		filter->argv[i + 1] = va_arg(ap, char *);

	filter->old_stdout = chk_positive(dup(STDOUT_FILENO),
		"Unable to duplicate STDOUT");
	chk_zero(pipe(filter->pipe_fh), "Unable to create pipe to subprocess");
	filter->pid = chk_non_negative(fork(), "Unable to create subprocess");
	if (filter->pid == 0) {
		close(filter->pipe_fh[1]);
		chk_non_negative(dup2(filter->pipe_fh[0], STDIN_FILENO),
			"Unable to use pipe as STDIN");
		execvp(filter->cmd, filter->argv);
		die_errno("Unable to exec subprocess %s", filter->cmd);
	}
	close(filter->pipe_fh[0]);
	chk_non_negative(dup2(filter->pipe_fh[1], STDOUT_FILENO),
		"Unable to use pipe as STDOUT");
	close(filter->pipe_fh[1]);
	return 0;
}

static int close_exec_filter(struct cgit_filter *base)
{
	struct cgit_exec_filter *filter = (struct cgit_exec_filter *)base;
	int i, exit_status = 0;

	chk_non_negative(dup2(filter->old_stdout, STDOUT_FILENO),
		"Unable to restore STDOUT");
	close(filter->old_stdout);
	if (filter->pid < 0)
		goto done;
	waitpid(filter->pid, &exit_status, 0);
	if (WIFEXITED(exit_status))
		goto done;
	die("Subprocess %s exited abnormally", filter->cmd);

done:
	for (i = 0; i < filter->base.argument_count; i++)
		filter->argv[i + 1] = NULL;
	return WEXITSTATUS(exit_status);

}

static void fprintf_exec_filter(struct cgit_filter *base, FILE *f, const char *prefix)
{
	struct cgit_exec_filter *filter = (struct cgit_exec_filter *)base;
	fprintf(f, "%sexec:%s\n", prefix, filter->cmd);
}

static void cleanup_exec_filter(struct cgit_filter *base)
{
	struct cgit_exec_filter *filter = (struct cgit_exec_filter *)base;
	if (filter->argv) {
		free(filter->argv);
		filter->argv = NULL;
	}
	if (filter->cmd) {
		free(filter->cmd);
		filter->cmd = NULL;
	}
}

static struct cgit_filter *new_exec_filter(const char *cmd, int argument_count)
{
	struct cgit_exec_filter *f;
	int args_size = 0;

	f = xmalloc(sizeof(*f));
	/* We leave argv for now and assign it below. */
	cgit_exec_filter_init(f, xstrdup(cmd), NULL);
	f->base.argument_count = argument_count;
	args_size = (2 + argument_count) * sizeof(char *);
	f->argv = xmalloc(args_size);
	memset(f->argv, 0, args_size);
	f->argv[0] = f->cmd;
	return &f->base;
}

void cgit_exec_filter_init(struct cgit_exec_filter *filter, char *cmd, char **argv)
{
	memset(filter, 0, sizeof(*filter));
	filter->base.open = open_exec_filter;
	filter->base.close = close_exec_filter;
	filter->base.fprintf = fprintf_exec_filter;
	filter->base.cleanup = cleanup_exec_filter;
	filter->cmd = cmd;
	filter->argv = argv;
	/* The argument count for open_filter is zero by default, unless called from new_filter, above. */
	filter->base.argument_count = 0;
}

#ifndef NO_LUA
struct lua_filter {
	struct cgit_filter base;
	char *script_file;
	lua_State *lua_state;
};

static void error_lua_filter(struct lua_filter *filter)
{
	die("Lua error in %s: %s", filter->script_file, lua_tostring(filter->lua_state, -1));
	lua_pop(filter->lua_state, 1);
}

static ssize_t write_lua_filter(struct cgit_filter *base, const void *buf, size_t count)
{
	struct lua_filter *filter = (struct lua_filter *)base;

	lua_getglobal(filter->lua_state, "filter_write");
	lua_pushlstring(filter->lua_state, buf, count);
	if (lua_pcall(filter->lua_state, 1, 0, 0)) {
		error_lua_filter(filter);
		errno = EIO;
		return -1;
	}
	return count;
}

static inline int hook_lua_filter(lua_State *lua_state, void (*fn)(const char *txt))
{
	const char *str;
	ssize_t (*save_filter_write)(struct cgit_filter *base, const void *buf, size_t count);
	struct cgit_filter *save_filter;

	str = lua_tostring(lua_state, 1);
	if (!str)
		return 0;

	save_filter_write = filter_write;
	save_filter = current_write_filter;
	unhook_write();
	fn(str);
	hook_write(save_filter, save_filter_write);

	return 0;
}

static int html_lua_filter(lua_State *lua_state)
{
	return hook_lua_filter(lua_state, html);
}

static int html_txt_lua_filter(lua_State *lua_state)
{
	return hook_lua_filter(lua_state, html_txt);
}

static int html_attr_lua_filter(lua_State *lua_state)
{
	return hook_lua_filter(lua_state, html_attr);
}

static int html_url_path_lua_filter(lua_State *lua_state)
{
	return hook_lua_filter(lua_state, html_url_path);
}

static int html_url_arg_lua_filter(lua_State *lua_state)
{
	return hook_lua_filter(lua_state, html_url_arg);
}

static int html_include_lua_filter(lua_State *lua_state)
{
	return hook_lua_filter(lua_state, (void (*)(const char *))html_include);
}

static void cleanup_lua_filter(struct cgit_filter *base)
{
	struct lua_filter *filter = (struct lua_filter *)base;

	if (!filter->lua_state)
		return;

	lua_close(filter->lua_state);
	filter->lua_state = NULL;
	if (filter->script_file) {
		free(filter->script_file);
		filter->script_file = NULL;
	}
}

static int init_lua_filter(struct lua_filter *filter)
{
	if (filter->lua_state)
		return 0;

	if (!(filter->lua_state = luaL_newstate()))
		return 1;

	luaL_openlibs(filter->lua_state);

	lua_pushcfunction(filter->lua_state, html_lua_filter);
	lua_setglobal(filter->lua_state, "html");
	lua_pushcfunction(filter->lua_state, html_txt_lua_filter);
	lua_setglobal(filter->lua_state, "html_txt");
	lua_pushcfunction(filter->lua_state, html_attr_lua_filter);
	lua_setglobal(filter->lua_state, "html_attr");
	lua_pushcfunction(filter->lua_state, html_url_path_lua_filter);
	lua_setglobal(filter->lua_state, "html_url_path");
	lua_pushcfunction(filter->lua_state, html_url_arg_lua_filter);
	lua_setglobal(filter->lua_state, "html_url_arg");
	lua_pushcfunction(filter->lua_state, html_include_lua_filter);
	lua_setglobal(filter->lua_state, "html_include");

	if (luaL_dofile(filter->lua_state, filter->script_file)) {
		error_lua_filter(filter);
		lua_close(filter->lua_state);
		filter->lua_state = NULL;
		return 1;
	}
	return 0;
}

static int open_lua_filter(struct cgit_filter *base, va_list ap)
{
	struct lua_filter *filter = (struct lua_filter *)base;
	int i;

	if (init_lua_filter(filter))
		return 1;

	hook_write(base, write_lua_filter);

	lua_getglobal(filter->lua_state, "filter_open");
	for (i = 0; i < filter->base.argument_count; ++i)
		lua_pushstring(filter->lua_state, va_arg(ap, char *));
	if (lua_pcall(filter->lua_state, filter->base.argument_count, 0, 0)) {
		error_lua_filter(filter);
		return 1;
	}
	return 0;
}

static int close_lua_filter(struct cgit_filter *base)
{
	struct lua_filter *filter = (struct lua_filter *)base;
	int ret = 0;

	lua_getglobal(filter->lua_state, "filter_close");
	if (lua_pcall(filter->lua_state, 0, 1, 0)) {
		error_lua_filter(filter);
		ret = -1;
	} else {
		ret = lua_tonumber(filter->lua_state, -1);
		lua_pop(filter->lua_state, 1);
	}

	unhook_write();
	return ret;
}

static void fprintf_lua_filter(struct cgit_filter *base, FILE *f, const char *prefix)
{
	struct lua_filter *filter = (struct lua_filter *)base;
	fprintf(f, "%slua:%s\n", prefix, filter->script_file);
}


static struct cgit_filter *new_lua_filter(const char *cmd, int argument_count)
{
	struct lua_filter *filter;

	filter = xmalloc(sizeof(*filter));
	memset(filter, 0, sizeof(*filter));
	filter->base.open = open_lua_filter;
	filter->base.close = close_lua_filter;
	filter->base.fprintf = fprintf_lua_filter;
	filter->base.cleanup = cleanup_lua_filter;
	filter->base.argument_count = argument_count;
	filter->script_file = xstrdup(cmd);

	return &filter->base;
}

#endif


int cgit_open_filter(struct cgit_filter *filter, ...)
{
	int result;
	va_list ap;
	if (!filter)
		return 0;
	va_start(ap, filter);
	result = filter->open(filter, ap);
	va_end(ap);
	return result;
}

int cgit_close_filter(struct cgit_filter *filter)
{
	if (!filter)
		return 0;
	return filter->close(filter);
}

void cgit_fprintf_filter(struct cgit_filter *filter, FILE *f, const char *prefix)
{
	filter->fprintf(filter, f, prefix);
}



static const struct {
	const char *prefix;
	struct cgit_filter *(*ctor)(const char *cmd, int argument_count);
} filter_specs[] = {
	{ "exec", new_exec_filter },
#ifndef NO_LUA
	{ "lua", new_lua_filter },
#endif
};

struct cgit_filter *cgit_new_filter(const char *cmd, filter_type filtertype)
{
	char *colon;
	int i;
	size_t len;
	int argument_count;

	if (!cmd || !cmd[0])
		return NULL;

	colon = strchr(cmd, ':');
	len = colon - cmd;
	/*
	 * In case we're running on Windows, don't allow a single letter before
	 * the colon.
	 */
	if (len == 1)
		colon = NULL;

	switch (filtertype) {
		case AUTH:
			argument_count = 12;
			break;

		case EMAIL:
			argument_count = 2;
			break;

		case OWNER:
			argument_count = 0;
			break;

		case SOURCE:
		case ABOUT:
			argument_count = 1;
			break;

		case COMMIT:
		default:
			argument_count = 0;
			break;
	}

	/* If no prefix is given, exec filter is the default. */
	if (!colon)
		return new_exec_filter(cmd, argument_count);

	for (i = 0; i < ARRAY_SIZE(filter_specs); i++) {
		if (len == strlen(filter_specs[i].prefix) &&
		    !strncmp(filter_specs[i].prefix, cmd, len))
			return filter_specs[i].ctor(colon + 1, argument_count);
	}

	die("Invalid filter type: %.*s", (int) len, cmd);
}