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	niro	532	/*
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	niro	1297	int p = (int )test;
368	niro	532
369	niro	1297	if (*p != INT_CONF) {
370	niro	532	fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
371	niro	1297	*p);
372	niro	532	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			}