scripts/basic/fixdep.c

/*
 * "Optimize" a list of dependencies as spit out by gcc -MD
 * for the kernel build
 * ===========================================================================
 *
 * Author       Kai Germaschewski
 * Copyright    2002 by Kai Germaschewski  <kai.germaschewski@gmx.de>
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 *
 * Introduction:
 *
 * gcc produces a very nice and correct list of dependencies which
 * tells make when to remake a file.
 *
 * To use this list as-is however has the drawback that virtually
 * every file in the kernel includes <linux/config.h> which then again
 * includes <linux/autoconf.h>
 *
 * If the user re-runs make *config, linux/autoconf.h will be
 * regenerated.  make notices that and will rebuild every file which
 * includes autoconf.h, i.e. basically all files. This is extremely
 * annoying if the user just changed CONFIG_HIS_DRIVER from n to m.
 *
 * So we play the same trick that "mkdep" played before. We replace
 * the dependency on linux/autoconf.h by a dependency on every config
 * option which is mentioned in any of the listed prequisites.
 *
 * To be exact, split-include populates a tree in include/config/,
 * e.g. include/config/his/driver.h, which contains the #define/#undef
 * for the CONFIG_HIS_DRIVER option.
 *
 * So if the user changes his CONFIG_HIS_DRIVER option, only the objects
 * which depend on "include/linux/config/his/driver.h" will be rebuilt,
 * so most likely only his driver ;-)
 *
 * The idea above dates, by the way, back to Michael E Chastain, AFAIK.
 *
 * So to get dependencies right, there are two issues:
 * o if any of the files the compiler read changed, we need to rebuild
 * o if the command line given to the compile the file changed, we
 *   better rebuild as well.
 *
 * The former is handled by using the -MD output, the later by saving
 * the command line used to compile the old object and comparing it
 * to the one we would now use.
 *
 * Again, also this idea is pretty old and has been discussed on
 * kbuild-devel a long time ago. I don't have a sensibly working
 * internet connection right now, so I rather don't mention names
 * without double checking.
 *
 * This code here has been based partially based on mkdep.c, which
 * says the following about its history:
 *
 *   Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.
 *   This is a C version of syncdep.pl by Werner Almesberger.
 *
 *
 * It is invoked as
 *
 *   fixdep <depfile> <target> <cmdline>
 *
 * and will read the dependency file <depfile>
 *
 * The transformed dependency snipped is written to stdout.
 *
 * It first generates a line
 *
 *   cmd_<target> = <cmdline>
 *
 * and then basically copies the .<target>.d file to stdout, in the
 * process filtering out the dependency on linux/autoconf.h and adding
 * dependencies on include/config/my/option.h for every
 * CONFIG_MY_OPTION encountered in any of the prequisites.
 *
 * It will also filter out all the dependencies on *.ver. We need
 * to make sure that the generated version checksum are globally up
 * to date before even starting the recursive build, so it's too late
 * at this point anyway.
 *
 * The algorithm to grep for "CONFIG_..." is bit unusual, but should
 * be fast ;-) We don't even try to really parse the header files, but
 * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will
 * be picked up as well. It's not a problem with respect to
 * correctness, since that can only give too many dependencies, thus
 * we cannot miss a rebuild. Since people tend to not mention totally
 * unrelated CONFIG_ options all over the place, it's not an
 * efficiency problem either.
 *
 * (Note: it'd be easy to port over the complete mkdep state machine,
 *  but I don't think the added complexity is worth it)
 */
/*
 * Note 2: if somebody writes HELLO_CONFIG_BOOM in a file, it will depend onto
 * CONFIG_BOOM. This could seem a bug (not too hard to fix), but please do not
 * fix it! Some UserModeLinux files (look at arch/um/) call CONFIG_BOOM as
 * UML_CONFIG_BOOM, to avoid conflicts with /usr/include/linux/autoconf.h,
 * through arch/um/include/uml-config.h; this fixdep "bug" makes sure that
 * those files will have correct dependencies.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include <ctype.h>
#include <arpa/inet.h>

#define INT_CONF ntohl(0x434f4e46)
#define INT_ONFI ntohl(0x4f4e4649)
#define INT_NFIG ntohl(0x4e464947)
#define INT_FIG_ ntohl(0x4649475f)

char *target;
char *depfile;
char *cmdline;

void usage(void)

{
	fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
	exit(1);
}

void print_cmdline(void)
{
	printf("cmd_%s := %s\n\n", target, cmdline);
}

char * str_config  = NULL;
int    size_config = 0;
int    len_config  = 0;

/*
 * Grow the configuration string to a desired length.
 * Usually the first growth is plenty.
 */
void grow_config(int len)
{
	while (len_config + len > size_config) {
		if (size_config == 0)
			size_config = 2048;
		str_config = realloc(str_config, size_config *= 2);
		if (str_config == NULL)
			{ perror("fixdep:malloc"); exit(1); }
	}
}


/*
 * Lookup a value in the configuration string.
 */
int is_defined_config(const char * name, int len)
{
	const char * pconfig;
	const char * plast = str_config + len_config - len;
	for ( pconfig = str_config + 1; pconfig < plast; pconfig++ ) {
		if (pconfig[ -1] == '\n'
		&&  pconfig[len] == '\n'
		&&  !memcmp(pconfig, name, len))
			return 1;
	}
	return 0;
}

/*
 * Add a new value to the configuration string.
 */
void define_config(const char * name, int len)
{
	grow_config(len + 1);

	memcpy(str_config+len_config, name, len);
	len_config += len;
	str_config[len_config++] = '\n';
}

/*
 * Clear the set of configuration strings.
 */
void clear_config(void)
{
	len_config = 0;
	define_config("", 0);
}

/*
 * Record the use of a CONFIG_* word.
 */
void use_config(char *m, int slen)
{
	char s[PATH_MAX];
	char *p;

	if (is_defined_config(m, slen))
	    return;

	define_config(m, slen);

	memcpy(s, m, slen); s[slen] = 0;

	for (p = s; p < s + slen; p++) {
		if (*p == '_')
			*p = '/';
		else
			*p = tolower((int)*p);
	}
	printf("    $(wildcard include/config/%s.h) \\\n", s);
}

void parse_config_file(char *map, size_t len)
{
	int *end = (int *) (map + len);
	/* start at +1, so that p can never be < map */
	int *m   = (int *) map + 1;
	char *p, *q;

	for (; m < end; m++) {
		if (*m == INT_CONF) { p = (char *) m  ; goto conf; }
		if (*m == INT_ONFI) { p = (char *) m-1; goto conf; }
		if (*m == INT_NFIG) { p = (char *) m-2; goto conf; }
		if (*m == INT_FIG_) { p = (char *) m-3; goto conf; }
		continue;
	conf:
		if (p > map + len - 7)
			continue;
		if (memcmp(p, "CONFIG_", 7))
			continue;
		for (q = p + 7; q < map + len; q++) {
			if (!(isalnum(*q) || *q == '_'))
				goto found;
		}
		continue;

	found:
		use_config(p+7, q-p-7);
	}
}

/* test is s ends in sub */
int strrcmp(char *s, char *sub)
{
	int slen = strlen(s);
	int sublen = strlen(sub);

	if (sublen > slen)
		return 1;

	return memcmp(s + slen - sublen, sub, sublen);
}

void do_config_file(char *filename)
{
	struct stat st;
	int fd;
	void *map;

	fd = open(filename, O_RDONLY);
	if (fd < 0) {
		fprintf(stderr, "fixdep: ");
		perror(filename);
		exit(2);
	}
	fstat(fd, &st);
	if (st.st_size == 0) {
		close(fd);
		return;
	}
	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	if ((long) map == -1) {
		perror("fixdep: mmap");
		close(fd);
		return;
	}

	parse_config_file(map, st.st_size);

	munmap(map, st.st_size);

	close(fd);
}

void parse_dep_file(void *map, size_t len)
{
	char *m = map;
	char *end = m + len;
	char *p;
	char s[PATH_MAX];

	p = strchr(m, ':');
	if (!p) {
		fprintf(stderr, "fixdep: parse error\n");
		exit(1);
	}
	memcpy(s, m, p-m); s[p-m] = 0;
	printf("deps_%s := \\\n", target);
	m = p+1;

	clear_config();

	while (m < end) {
		while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
			m++;
		p = m;
		while (p < end && *p != ' ') p++;
		if (p == end) {
			do p--; while (!isalnum(*p));
			p++;
		}
		memcpy(s, m, p-m); s[p-m] = 0;
		if (strrcmp(s, "include/linux/autoconf.h") &&
		    strrcmp(s, "arch/um/include/uml-config.h") &&
		    strrcmp(s, ".ver")) {
			printf("  %s \\\n", s);
			do_config_file(s);
		}
		m = p + 1;
	}
	printf("\n%s: $(deps_%s)\n\n", target, target);
	printf("$(deps_%s):\n", target);
}

void print_deps(void)
{
	struct stat st;
	int fd;
	void *map;

	fd = open(depfile, O_RDONLY);
	if (fd < 0) {
		fprintf(stderr, "fixdep: ");
		perror(depfile);
		exit(2);
	}
	fstat(fd, &st);
	if (st.st_size == 0) {
		fprintf(stderr,"fixdep: %s is empty\n",depfile);
		close(fd);
		return;
	}
	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
	if ((long) map == -1) {
		perror("fixdep: mmap");
		close(fd);
		return;
	}

	parse_dep_file(map, st.st_size);

	munmap(map, st.st_size);

	close(fd);
}

void traps(void)
{
	static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
	int *p = (int *)test;

	if (*p != INT_CONF) {
		fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
			*p);
		exit(2);
	}
}

int main(int argc, char *argv[])
{
	traps();

	if (argc != 4)
		usage();

	depfile = argv[1];
	target = argv[2];
	cmdline = argv[3];

	print_cmdline();
	print_deps();

	return 0;
}
1	/*
2	* "Optimize" a list of dependencies as spit out by gcc -MD
3	* for the kernel build
4	* ===========================================================================
5	*
6	* Author Kai Germaschewski
7	* Copyright 2002 by Kai Germaschewski <kai.germaschewski@gmx.de>
8	*
9	* This software may be used and distributed according to the terms
10	* of the GNU General Public License, incorporated herein by reference.
11	*
12	*
13	* Introduction:
14	*
15	* gcc produces a very nice and correct list of dependencies which
16	* tells make when to remake a file.
17	*
18	* To use this list as-is however has the drawback that virtually
19	* every file in the kernel includes <linux/config.h> which then again
20	* includes <linux/autoconf.h>
21	*
22	* If the user re-runs make *config, linux/autoconf.h will be
23	* regenerated. make notices that and will rebuild every file which
24	* includes autoconf.h, i.e. basically all files. This is extremely
25	* annoying if the user just changed CONFIG_HIS_DRIVER from n to m.
26	*
27	* So we play the same trick that "mkdep" played before. We replace
28	* the dependency on linux/autoconf.h by a dependency on every config
29	* option which is mentioned in any of the listed prequisites.
30	*
31	* To be exact, split-include populates a tree in include/config/,
32	* e.g. include/config/his/driver.h, which contains the #define/#undef
33	* for the CONFIG_HIS_DRIVER option.
34	*
35	* So if the user changes his CONFIG_HIS_DRIVER option, only the objects
36	* which depend on "include/linux/config/his/driver.h" will be rebuilt,
37	* so most likely only his driver ;-)
38	*
39	* The idea above dates, by the way, back to Michael E Chastain, AFAIK.
40	*
41	* So to get dependencies right, there are two issues:
42	* o if any of the files the compiler read changed, we need to rebuild
43	* o if the command line given to the compile the file changed, we
44	* better rebuild as well.
45	*
46	* The former is handled by using the -MD output, the later by saving
47	* the command line used to compile the old object and comparing it
48	* to the one we would now use.
49	*
50	* Again, also this idea is pretty old and has been discussed on
51	* kbuild-devel a long time ago. I don't have a sensibly working
52	* internet connection right now, so I rather don't mention names
53	* without double checking.
54	*
55	* This code here has been based partially based on mkdep.c, which
56	* says the following about its history:
57	*
58	* Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.
59	* This is a C version of syncdep.pl by Werner Almesberger.
60	*
61	*
62	* It is invoked as
63	*
64	* fixdep <depfile> <target> <cmdline>
65	*
66	* and will read the dependency file <depfile>
67	*
68	* The transformed dependency snipped is written to stdout.
69	*
70	* It first generates a line
71	*
72	* cmd_<target> = <cmdline>
73	*
74	* and then basically copies the .<target>.d file to stdout, in the
75	* process filtering out the dependency on linux/autoconf.h and adding
76	* dependencies on include/config/my/option.h for every
77	* CONFIG_MY_OPTION encountered in any of the prequisites.
78	*
79	* It will also filter out all the dependencies on *.ver. We need
80	* to make sure that the generated version checksum are globally up
81	* to date before even starting the recursive build, so it's too late
82	* at this point anyway.
83	*
84	* The algorithm to grep for "CONFIG_..." is bit unusual, but should
85	* be fast ;-) We don't even try to really parse the header files, but
86	* merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will
87	* be picked up as well. It's not a problem with respect to
88	* correctness, since that can only give too many dependencies, thus
89	* we cannot miss a rebuild. Since people tend to not mention totally
90	* unrelated CONFIG_ options all over the place, it's not an
91	* efficiency problem either.
92	*
93	* (Note: it'd be easy to port over the complete mkdep state machine,
94	* but I don't think the added complexity is worth it)
95	*/
96	/*
97	* Note 2: if somebody writes HELLO_CONFIG_BOOM in a file, it will depend onto
98	* CONFIG_BOOM. This could seem a bug (not too hard to fix), but please do not
99	* fix it! Some UserModeLinux files (look at arch/um/) call CONFIG_BOOM as
100	* UML_CONFIG_BOOM, to avoid conflicts with /usr/include/linux/autoconf.h,
101	* through arch/um/include/uml-config.h; this fixdep "bug" makes sure that
102	* those files will have correct dependencies.
103	*/
104
105	#include <sys/types.h>
106	#include <sys/stat.h>
107	#include <sys/mman.h>
108	#include <unistd.h>
109	#include <fcntl.h>
110	#include <string.h>
111	#include <stdlib.h>
112	#include <stdio.h>
113	#include <limits.h>
114	#include <ctype.h>
115	#include <arpa/inet.h>
116
117	#define INT_CONF ntohl(0x434f4e46)
118	#define INT_ONFI ntohl(0x4f4e4649)
119	#define INT_NFIG ntohl(0x4e464947)
120	#define INT_FIG_ ntohl(0x4649475f)
121
122	char *target;
123	char *depfile;
124	char *cmdline;
125
126	void usage(void)
127
128	{
129	fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
130	exit(1);
131	}
132
133	void print_cmdline(void)
134	{
135	printf("cmd_%s := %s\n\n", target, cmdline);
136	}
137
138	char * str_config = NULL;
139	int size_config = 0;
140	int len_config = 0;
141
142	/*
143	* Grow the configuration string to a desired length.
144	* Usually the first growth is plenty.
145	*/
146	void grow_config(int len)
147	{
148	while (len_config + len > size_config) {
149	if (size_config == 0)
150	size_config = 2048;
151	str_config = realloc(str_config, size_config *= 2);
152	if (str_config == NULL)
153	{ perror("fixdep:malloc"); exit(1); }
154	}
155	}
156
157
158
159	/*
160	* Lookup a value in the configuration string.
161	*/
162	int is_defined_config(const char * name, int len)
163	{
164	const char * pconfig;
165	const char * plast = str_config + len_config - len;
166	for ( pconfig = str_config + 1; pconfig < plast; pconfig++ ) {
167	if (pconfig[ -1] == '\n'
168	&& pconfig[len] == '\n'
169	&& !memcmp(pconfig, name, len))
170	return 1;
171	}
172	return 0;
173	}
174
175	/*
176	* Add a new value to the configuration string.
177	*/
178	void define_config(const char * name, int len)
179	{
180	grow_config(len + 1);
181
182	memcpy(str_config+len_config, name, len);
183	len_config += len;
184	str_config[len_config++] = '\n';
185	}
186
187	/*
188	* Clear the set of configuration strings.
189	*/
190	void clear_config(void)
191	{
192	len_config = 0;
193	define_config("", 0);
194	}
195
196	/*
197	* Record the use of a CONFIG_* word.
198	*/
199	void use_config(char *m, int slen)
200	{
201	char s[PATH_MAX];
202	char *p;
203
204	if (is_defined_config(m, slen))
205	return;
206
207	define_config(m, slen);
208
209	memcpy(s, m, slen); s[slen] = 0;
210
211	for (p = s; p < s + slen; p++) {
212	if (*p == '_')
213	*p = '/';
214	else
215	p = tolower((int)p);
216	}
217	printf(" $(wildcard include/config/%s.h) \\\n", s);
218	}
219
220	void parse_config_file(char *map, size_t len)
221	{
222	int end = (int ) (map + len);
223	/* start at +1, so that p can never be < map */
224	int m = (int ) map + 1;
225	char p, q;
226
227	for (; m < end; m++) {
228	if (m == INT_CONF) { p = (char ) m ; goto conf; }
229	if (m == INT_ONFI) { p = (char ) m-1; goto conf; }
230	if (m == INT_NFIG) { p = (char ) m-2; goto conf; }
231	if (m == INT_FIG_) { p = (char ) m-3; goto conf; }
232	continue;
233	conf:
234	if (p > map + len - 7)
235	continue;
236	if (memcmp(p, "CONFIG_", 7))
237	continue;
238	for (q = p + 7; q < map + len; q++) {
239	if (!(isalnum(q) \|\| q == '_'))
240	goto found;
241	}
242	continue;
243
244	found:
245	use_config(p+7, q-p-7);
246	}
247	}
248
249	/* test is s ends in sub */
250	int strrcmp(char s, char sub)
251	{
252	int slen = strlen(s);
253	int sublen = strlen(sub);
254
255	if (sublen > slen)
256	return 1;
257
258	return memcmp(s + slen - sublen, sub, sublen);
259	}
260
261	void do_config_file(char *filename)
262	{
263	struct stat st;
264	int fd;
265	void *map;
266
267	fd = open(filename, O_RDONLY);
268	if (fd < 0) {
269	fprintf(stderr, "fixdep: ");
270	perror(filename);
271	exit(2);
272	}
273	fstat(fd, &st);
274	if (st.st_size == 0) {
275	close(fd);
276	return;
277	}
278	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
279	if ((long) map == -1) {
280	perror("fixdep: mmap");
281	close(fd);
282	return;
283	}
284
285	parse_config_file(map, st.st_size);
286
287	munmap(map, st.st_size);
288
289	close(fd);
290	}
291
292	void parse_dep_file(void *map, size_t len)
293	{
294	char *m = map;
295	char *end = m + len;
296	char *p;
297	char s[PATH_MAX];
298
299	p = strchr(m, ':');
300	if (!p) {
301	fprintf(stderr, "fixdep: parse error\n");
302	exit(1);
303	}
304	memcpy(s, m, p-m); s[p-m] = 0;
305	printf("deps_%s := \\\n", target);
306	m = p+1;
307
308	clear_config();
309
310	while (m < end) {
311	while (m < end && (m == ' ' \|\| m == '\\' \|\| *m == '\n'))
312	m++;
313	p = m;
314	while (p < end && *p != ' ') p++;
315	if (p == end) {
316	do p--; while (!isalnum(*p));
317	p++;
318	}
319	memcpy(s, m, p-m); s[p-m] = 0;
320	if (strrcmp(s, "include/linux/autoconf.h") &&
321	strrcmp(s, "arch/um/include/uml-config.h") &&
322	strrcmp(s, ".ver")) {
323	printf(" %s \\\n", s);
324	do_config_file(s);
325	}
326	m = p + 1;
327	}
328	printf("\n%s: $(deps_%s)\n\n", target, target);
329	printf("$(deps_%s):\n", target);
330	}
331
332	void print_deps(void)
333	{
334	struct stat st;
335	int fd;
336	void *map;
337
338	fd = open(depfile, O_RDONLY);
339	if (fd < 0) {
340	fprintf(stderr, "fixdep: ");
341	perror(depfile);
342	exit(2);
343	}
344	fstat(fd, &st);
345	if (st.st_size == 0) {
346	fprintf(stderr,"fixdep: %s is empty\n",depfile);
347	close(fd);
348	return;
349	}
350	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
351	if ((long) map == -1) {
352	perror("fixdep: mmap");
353	close(fd);
354	return;
355	}
356
357	parse_dep_file(map, st.st_size);
358
359	munmap(map, st.st_size);
360
361	close(fd);
362	}
363
364	void traps(void)
365	{
366	static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
367	int p = (int )test;
368
369	if (*p != INT_CONF) {
370	fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
371	*p);
372	exit(2);
373	}
374	}
375
376	int main(int argc, char *argv[])
377	{
378	traps();
379
380	if (argc != 4)
381	usage();
382
383	depfile = argv[1];
384	target = argv[2];
385	cmdline = argv[3];
386
387	print_cmdline();
388	print_deps();
389
390	return 0;
391	}