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>

/* bbox: not needed
#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);
}

/*
 * Print out the commandline prefixed with cmd_<target filename> :=
 */
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)
{
	/* modified for bbox */
	char *end_4 = map + len - 4; /* 4 == length of "USE_" */
	char *end_7 = map + len - 7;
	char *p = map;
	char *q;
	int off;

	for (; p < end_4; p++) {
		if (p < end_7 && p[6] == '_') {
			if (!memcmp(p, "CONFIG", 6)) goto conf7;
			if (!memcmp(p, "ENABLE", 6)) goto conf7;
		}
		/* We have at least 5 chars: for() has
		 * "p < end-4", not "p <= end-4"
		 * therefore we don't need to check p <= end-5 here */
		if (p[4] == '_')
			if (!memcmp(p, "SKIP", 4)) goto conf5;
		/* Ehhh, gcc is too stupid to just compare it as 32bit int */
		if (p[0] == 'U')
			if (!memcmp(p, "USE_", 4)) goto conf4;
		continue;

	conf4:	off = 4;
	conf5:	off = 5;
	conf7:	off = 7;
		p += off;
		for (q = p; q < end_4+4; q++) {
			if (!(isalnum(*q) || *q == '_'))
				break;
		}
		use_config(p, q-p);
	}
}

/* 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 = memchr(m, ':', len);
	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/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)
{
/* bbox: not needed
	static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";

	if (*(int *)test != INT_CONF) {
		fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
			*(int *)test);
		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	/* bbox: not needed
118	#define INT_CONF ntohl(0x434f4e46)
119	#define INT_ONFI ntohl(0x4f4e4649)
120	#define INT_NFIG ntohl(0x4e464947)
121	#define INT_FIG_ ntohl(0x4649475f)
122	*/
123
124	char *target;
125	char *depfile;
126	char *cmdline;
127
128	void usage(void)
129
130	{
131	fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
132	exit(1);
133	}
134
135	/*
136	* Print out the commandline prefixed with cmd_<target filename> :=
137	*/
138	void print_cmdline(void)
139	{
140	printf("cmd_%s := %s\n\n", target, cmdline);
141	}
142
143	char * str_config = NULL;
144	int size_config = 0;
145	int len_config = 0;
146
147	/*
148	* Grow the configuration string to a desired length.
149	* Usually the first growth is plenty.
150	*/
151	void grow_config(int len)
152	{
153	while (len_config + len > size_config) {
154	if (size_config == 0)
155	size_config = 2048;
156	str_config = realloc(str_config, size_config *= 2);
157	if (str_config == NULL)
158	{ perror("fixdep:malloc"); exit(1); }
159	}
160	}
161
162
163
164	/*
165	* Lookup a value in the configuration string.
166	*/
167	int is_defined_config(const char * name, int len)
168	{
169	const char * pconfig;
170	const char * plast = str_config + len_config - len;
171	for ( pconfig = str_config + 1; pconfig < plast; pconfig++ ) {
172	if (pconfig[ -1] == '\n'
173	&& pconfig[len] == '\n'
174	&& !memcmp(pconfig, name, len))
175	return 1;
176	}
177	return 0;
178	}
179
180	/*
181	* Add a new value to the configuration string.
182	*/
183	void define_config(const char * name, int len)
184	{
185	grow_config(len + 1);
186
187	memcpy(str_config+len_config, name, len);
188	len_config += len;
189	str_config[len_config++] = '\n';
190	}
191
192	/*
193	* Clear the set of configuration strings.
194	*/
195	void clear_config(void)
196	{
197	len_config = 0;
198	define_config("", 0);
199	}
200
201	/*
202	* Record the use of a CONFIG_* word.
203	*/
204	void use_config(char *m, int slen)
205	{
206	char s[PATH_MAX];
207	char *p;
208
209	if (is_defined_config(m, slen))
210	return;
211
212	define_config(m, slen);
213
214	memcpy(s, m, slen); s[slen] = 0;
215
216	for (p = s; p < s + slen; p++) {
217	if (*p == '_')
218	*p = '/';
219	else
220	p = tolower((int)p);
221	}
222	printf(" $(wildcard include/config/%s.h) \\\n", s);
223	}
224
225	void parse_config_file(char *map, size_t len)
226	{
227	/* modified for bbox */
228	char end_4 = map + len - 4; / 4 == length of "USE_" */
229	char *end_7 = map + len - 7;
230	char *p = map;
231	char *q;
232	int off;
233
234	for (; p < end_4; p++) {
235	if (p < end_7 && p[6] == '_') {
236	if (!memcmp(p, "CONFIG", 6)) goto conf7;
237	if (!memcmp(p, "ENABLE", 6)) goto conf7;
238	}
239	/* We have at least 5 chars: for() has
240	* "p < end-4", not "p <= end-4"
241	* therefore we don't need to check p <= end-5 here */
242	if (p[4] == '_')
243	if (!memcmp(p, "SKIP", 4)) goto conf5;
244	/* Ehhh, gcc is too stupid to just compare it as 32bit int */
245	if (p[0] == 'U')
246	if (!memcmp(p, "USE_", 4)) goto conf4;
247	continue;
248
249	conf4: off = 4;
250	conf5: off = 5;
251	conf7: off = 7;
252	p += off;
253	for (q = p; q < end_4+4; q++) {
254	if (!(isalnum(q) \|\| q == '_'))
255	break;
256	}
257	use_config(p, q-p);
258	}
259	}
260
261	/* test is s ends in sub */
262	int strrcmp(char s, char sub)
263	{
264	int slen = strlen(s);
265	int sublen = strlen(sub);
266
267	if (sublen > slen)
268	return 1;
269
270	return memcmp(s + slen - sublen, sub, sublen);
271	}
272
273	void do_config_file(char *filename)
274	{
275	struct stat st;
276	int fd;
277	void *map;
278
279	fd = open(filename, O_RDONLY);
280	if (fd < 0) {
281	fprintf(stderr, "fixdep: ");
282	perror(filename);
283	exit(2);
284	}
285	fstat(fd, &st);
286	if (st.st_size == 0) {
287	close(fd);
288	return;
289	}
290	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
291	if ((long) map == -1) {
292	perror("fixdep: mmap");
293	close(fd);
294	return;
295	}
296
297	parse_config_file(map, st.st_size);
298
299	munmap(map, st.st_size);
300
301	close(fd);
302	}
303
304	void parse_dep_file(void *map, size_t len)
305	{
306	char *m = map;
307	char *end = m + len;
308	char *p;
309	char s[PATH_MAX];
310
311	p = memchr(m, ':', len);
312	if (!p) {
313	fprintf(stderr, "fixdep: parse error\n");
314	exit(1);
315	}
316	memcpy(s, m, p-m); s[p-m] = 0;
317	printf("deps_%s := \\\n", target);
318	m = p+1;
319
320	clear_config();
321
322	while (m < end) {
323	while (m < end && (m == ' ' \|\| m == '\\' \|\| *m == '\n'))
324	m++;
325	p = m;
326	while (p < end && *p != ' ') p++;
327	if (p == end) {
328	do p--; while (!isalnum(*p));
329	p++;
330	}
331	memcpy(s, m, p-m); s[p-m] = 0;
332	if (strrcmp(s, "include/autoconf.h") &&
333	strrcmp(s, "arch/um/include/uml-config.h") &&
334	strrcmp(s, ".ver")) {
335	printf(" %s \\\n", s);
336	do_config_file(s);
337	}
338	m = p + 1;
339	}
340	printf("\n%s: $(deps_%s)\n\n", target, target);
341	printf("$(deps_%s):\n", target);
342	}
343
344	void print_deps(void)
345	{
346	struct stat st;
347	int fd;
348	void *map;
349
350	fd = open(depfile, O_RDONLY);
351	if (fd < 0) {
352	fprintf(stderr, "fixdep: ");
353	perror(depfile);
354	exit(2);
355	}
356	fstat(fd, &st);
357	if (st.st_size == 0) {
358	fprintf(stderr,"fixdep: %s is empty\n",depfile);
359	close(fd);
360	return;
361	}
362	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
363	if ((long) map == -1) {
364	perror("fixdep: mmap");
365	close(fd);
366	return;
367	}
368
369	parse_dep_file(map, st.st_size);
370
371	munmap(map, st.st_size);
372
373	close(fd);
374	}
375
376	void traps(void)
377	{
378	/* bbox: not needed
379	static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
380
381	if ((int )test != INT_CONF) {
382	fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
383	(int )test);
384	exit(2);
385	}
386	*/
387	}
388
389	int main(int argc, char *argv[])
390	{
391	traps();
392
393	if (argc != 4)
394	usage();
395
396	depfile = argv[1];
397	target = argv[2];
398	cmdline = argv[3];
399
400	print_cmdline();
401	print_deps();
402
403	return 0;
404	}