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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 autoconf.h.
20 *
21 * If the user re-runs make *config, autoconf.h will be
22 * regenerated. make notices that and will rebuild every file which
23 * includes autoconf.h, i.e. basically all files. This is extremely
24 * annoying if the user just changed CONFIG_HIS_DRIVER from n to m.
25 *
26 * So we play the same trick that "mkdep" played before. We replace
27 * the dependency on autoconf.h by a dependency on every config
28 * option which is mentioned in any of the listed prequisites.
29 *
30 * kconfig populates a tree in include/config/ with an empty file
31 * for each config symbol and when the configuration is updated
32 * the files representing changed config options are touched
33 * which then let make pick up the changes and the files that use
34 * the config symbols are rebuilt.
35 *
36 * So if the user changes his CONFIG_HIS_DRIVER option, only the objects
37 * which depend on "include/linux/config/his/driver.h" will be rebuilt,
38 * so most likely only his driver ;-)
39 *
40 * The idea above dates, by the way, back to Michael E Chastain, AFAIK.
41 *
42 * So to get dependencies right, there are two issues:
43 * o if any of the files the compiler read changed, we need to rebuild
44 * o if the command line given to the compile the file changed, we
45 * better rebuild as well.
46 *
47 * The former is handled by using the -MD output, the later by saving
48 * the command line used to compile the old object and comparing it
49 * to the one we would now use.
50 *
51 * Again, also this idea is pretty old and has been discussed on
52 * kbuild-devel a long time ago. I don't have a sensibly working
53 * internet connection right now, so I rather don't mention names
54 * without double checking.
55 *
56 * This code here has been based partially based on mkdep.c, which
57 * says the following about its history:
58 *
59 * Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.
60 * This is a C version of syncdep.pl by Werner Almesberger.
61 *
62 *
63 * It is invoked as
64 *
65 * fixdep <depfile> <target> <cmdline>
66 *
67 * and will read the dependency file <depfile>
68 *
69 * The transformed dependency snipped is written to stdout.
70 *
71 * It first generates a line
72 *
73 * cmd_<target> = <cmdline>
74 *
75 * and then basically copies the .<target>.d file to stdout, in the
76 * process filtering out the dependency on autoconf.h and adding
77 * dependencies on include/config/my/option.h for every
78 * CONFIG_MY_OPTION encountered in any of the prequisites.
79 *
80 * It will also filter out all the dependencies on *.ver. We need
81 * to make sure that the generated version checksum are globally up
82 * to date before even starting the recursive build, so it's too late
83 * at this point anyway.
84 *
85 * The algorithm to grep for "CONFIG_..." is bit unusual, but should
86 * be fast ;-) We don't even try to really parse the header files, but
87 * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will
88 * be picked up as well. It's not a problem with respect to
89 * correctness, since that can only give too many dependencies, thus
90 * we cannot miss a rebuild. Since people tend to not mention totally
91 * unrelated CONFIG_ options all over the place, it's not an
92 * efficiency problem either.
93 *
94 * (Note: it'd be easy to port over the complete mkdep state machine,
95 * but I don't think the added complexity is worth it)
96 */
97/*
98 * Note 2: if somebody writes HELLO_CONFIG_BOOM in a file, it will depend onto
99 * CONFIG_BOOM. This could seem a bug (not too hard to fix), but please do not
100 * fix it! Some UserModeLinux files (look at arch/um/) call CONFIG_BOOM as
101 * UML_CONFIG_BOOM, to avoid conflicts with /usr/include/linux/autoconf.h,
102 * through arch/um/include/uml-config.h; this fixdep "bug" makes sure that
103 * those files will have correct dependencies.
104 */
105
106#include <sys/types.h>
107#include <sys/stat.h>
108#include <sys/mman.h>
109#include <unistd.h>
110#include <fcntl.h>
111#include <string.h>
112#include <stdlib.h>
113#include <stdio.h>
114#include <limits.h>
115#include <ctype.h>
116#include <arpa/inet.h>
117
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
123char *target;
124char *depfile;
125char *cmdline;
126
127static void usage(void)
128{
129 fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
130 exit(1);
131}
132
133/*
134 * Print out the commandline prefixed with cmd_<target filename> :=
135 */
136static void print_cmdline(void)
137{
138 printf("cmd_%s := %s\n\n", target, cmdline);
139}
140
141struct item {
142 struct item *next;
143 unsigned int len;
144 unsigned int hash;
145 char name[0];
146};
147
148#define HASHSZ 256
149static struct item *hashtab[HASHSZ];
150
151static unsigned int strhash(const char *str, unsigned int sz)
152{
153 /* fnv32 hash */
154 unsigned int i, hash = 2166136261U;
155
156 for (i = 0; i < sz; i++)
157 hash = (hash ^ str[i]) * 0x01000193;
158 return hash;
159}
160
161/*
162 * Lookup a value in the configuration string.
163 */
164static int is_defined_config(const char *name, int len, unsigned int hash)
165{
166 struct item *aux;
167
168 for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) {
169 if (aux->hash == hash && aux->len == len &&
170 memcmp(aux->name, name, len) == 0)
171 return 1;
172 }
173 return 0;
174}
175
176/*
177 * Add a new value to the configuration string.
178 */
179static void define_config(const char *name, int len, unsigned int hash)
180{
181 struct item *aux = malloc(sizeof(*aux) + len);
182
183 if (!aux) {
184 perror("fixdep:malloc");
185 exit(1);
186 }
187 memcpy(aux->name, name, len);
188 aux->len = len;
189 aux->hash = hash;
190 aux->next = hashtab[hash % HASHSZ];
191 hashtab[hash % HASHSZ] = aux;
192}
193
194/*
195 * Record the use of a CONFIG_* word.
196 */
197static void use_config(const char *m, int slen)
198{
199 unsigned int hash = strhash(m, slen);
200 int c, i;
201
202 if (is_defined_config(m, slen, hash))
203 return;
204
205 define_config(m, slen, hash);
206
207 printf(" $(wildcard include/config/");
208 for (i = 0; i < slen; i++) {
209 c = m[i];
210 if (c == '_')
211 c = '/';
212 else
213 c = tolower(c);
214 putchar(c);
215 }
216 printf(".h) \\\n");
217}
218
219static void parse_config_file(const char *map, size_t len)
220{
221 const int *end = (const int *) (map + len);
222 /* start at +1, so that p can never be < map */
223 const int *m = (const int *) map + 1;
224 const char *p, *q;
225
226 for (; m < end; m++) {
227 if (*m == INT_CONF) { p = (char *) m ; goto conf; }
228 if (*m == INT_ONFI) { p = (char *) m-1; goto conf; }
229 if (*m == INT_NFIG) { p = (char *) m-2; goto conf; }
230 if (*m == INT_FIG_) { p = (char *) m-3; goto conf; }
231 continue;
232 conf:
233 if (p > map + len - 7)
234 continue;
235 if (memcmp(p, "CONFIG_", 7))
236 continue;
237 p += 7;
238 for (q = p; q < map + len; q++) {
239 if (!(isalnum(*q) || *q == '_'))
240 goto found;
241 }
242 continue;
243
244 found:
245 if (!memcmp(q - 7, "_MODULE", 7))
246 q -= 7;
247 if (q - p < 0)
248 continue;
249 use_config(p, q - p);
250 }
251}
252
253/* test is s ends in sub */
254static int strrcmp(const char *s, const char *sub)
255{
256 int slen = strlen(s);
257 int sublen = strlen(sub);
258
259 if (sublen > slen)
260 return 1;
261
262 return memcmp(s + slen - sublen, sub, sublen);
263}
264
265static void do_config_file(const char *filename)
266{
267 struct stat st;
268 int fd;
269 void *map;
270
271 fd = open(filename, O_RDONLY);
272 if (fd < 0) {
273 fprintf(stderr, "fixdep: error opening config file: ");
274 perror(filename);
275 exit(2);
276 }
277 if (fstat(fd, &st) < 0) {
278 fprintf(stderr, "fixdep: error fstat'ing config file: ");
279 perror(filename);
280 exit(2);
281 }
282 if (st.st_size == 0) {
283 close(fd);
284 return;
285 }
286 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
287 if ((long) map == -1) {
288 perror("fixdep: mmap");
289 close(fd);
290 return;
291 }
292
293 parse_config_file(map, st.st_size);
294
295 munmap(map, st.st_size);
296
297 close(fd);
298}
299
300/*
301 * Important: The below generated source_foo.o and deps_foo.o variable
302 * assignments are parsed not only by make, but also by the rather simple
303 * parser in scripts/mod/sumversion.c.
304 */
305static void parse_dep_file(void *map, size_t len)
306{
307 char *m = map;
308 char *end = m + len;
309 char *p;
310 char s[PATH_MAX];
311 int is_target;
312 int saw_any_target = 0;
313 int is_first_dep = 0;
314
315 while (m < end) {
316 /* Skip any "white space" */
317 while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
318 m++;
319 /* Find next "white space" */
320 p = m;
321 while (p < end && *p != ' ' && *p != '\\' && *p != '\n')
322 p++;
323 /* Is the token we found a target name? */
324 is_target = (*(p-1) == ':');
325 /* Don't write any target names into the dependency file */
326 if (is_target) {
327 /* The /next/ file is the first dependency */
328 is_first_dep = 1;
329 } else {
330 /* Save this token/filename */
331 memcpy(s, m, p-m);
332 s[p - m] = 0;
333
334 /* Ignore certain dependencies */
335 if (strrcmp(s, "include/generated/autoconf.h") &&
336 strrcmp(s, "arch/um/include/uml-config.h") &&
337 strrcmp(s, "include/linux/kconfig.h") &&
338 strrcmp(s, ".ver")) {
339 /*
340 * Do not list the source file as dependency,
341 * so that kbuild is not confused if a .c file
342 * is rewritten into .S or vice versa. Storing
343 * it in source_* is needed for modpost to
344 * compute srcversions.
345 */
346 if (is_first_dep) {
347 /*
348 * If processing the concatenation of
349 * multiple dependency files, only
350 * process the first target name, which
351 * will be the original source name,
352 * and ignore any other target names,
353 * which will be intermediate temporary
354 * files.
355 */
356 if (!saw_any_target) {
357 saw_any_target = 1;
358 printf("source_%s := %s\n\n",
359 target, s);
360 printf("deps_%s := \\\n",
361 target);
362 }
363 is_first_dep = 0;
364 } else
365 printf(" %s \\\n", s);
366 do_config_file(s);
367 }
368 }
369 /*
370 * Start searching for next token immediately after the first
371 * "whitespace" character that follows this token.
372 */
373 m = p + 1;
374 }
375
376 if (!saw_any_target) {
377 fprintf(stderr, "fixdep: parse error; no targets found\n");
378 exit(1);
379 }
380
381 printf("\n%s: $(deps_%s)\n\n", target, target);
382 printf("$(deps_%s):\n", target);
383}
384
385static void print_deps(void)
386{
387 struct stat st;
388 int fd;
389 void *map;
390
391 fd = open(depfile, O_RDONLY);
392 if (fd < 0) {
393 fprintf(stderr, "fixdep: error opening depfile: ");
394 perror(depfile);
395 exit(2);
396 }
397 if (fstat(fd, &st) < 0) {
398 fprintf(stderr, "fixdep: error fstat'ing depfile: ");
399 perror(depfile);
400 exit(2);
401 }
402 if (st.st_size == 0) {
403 fprintf(stderr,"fixdep: %s is empty\n",depfile);
404 close(fd);
405 return;
406 }
407 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
408 if ((long) map == -1) {
409 perror("fixdep: mmap");
410 close(fd);
411 return;
412 }
413
414 parse_dep_file(map, st.st_size);
415
416 munmap(map, st.st_size);
417
418 close(fd);
419}
420
421static void traps(void)
422{
423 static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
424 int *p = (int *)test;
425
426 if (*p != INT_CONF) {
427 fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianness? %#x\n",
428 *p);
429 exit(2);
430 }
431}
432
433int main(int argc, char *argv[])
434{
435 traps();
436
437 if (argc != 4)
438 usage();
439
440 depfile = argv[1];
441 target = argv[2];
442 cmdline = argv[3];
443
444 print_cmdline();
445 print_deps();
446
447 return 0;
448}
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 autoconf.h.
20 *
21 * If the user re-runs make *config, autoconf.h will be
22 * regenerated. make notices that and will rebuild every file which
23 * includes autoconf.h, i.e. basically all files. This is extremely
24 * annoying if the user just changed CONFIG_HIS_DRIVER from n to m.
25 *
26 * So we play the same trick that "mkdep" played before. We replace
27 * the dependency on autoconf.h by a dependency on every config
28 * option which is mentioned in any of the listed prerequisites.
29 *
30 * kconfig populates a tree in include/config/ with an empty file
31 * for each config symbol and when the configuration is updated
32 * the files representing changed config options are touched
33 * which then let make pick up the changes and the files that use
34 * the config symbols are rebuilt.
35 *
36 * So if the user changes his CONFIG_HIS_DRIVER option, only the objects
37 * which depend on "include/config/HIS_DRIVER" will be rebuilt,
38 * so most likely only his driver ;-)
39 *
40 * The idea above dates, by the way, back to Michael E Chastain, AFAIK.
41 *
42 * So to get dependencies right, there are two issues:
43 * o if any of the files the compiler read changed, we need to rebuild
44 * o if the command line given to the compile the file changed, we
45 * better rebuild as well.
46 *
47 * The former is handled by using the -MD output, the later by saving
48 * the command line used to compile the old object and comparing it
49 * to the one we would now use.
50 *
51 * Again, also this idea is pretty old and has been discussed on
52 * kbuild-devel a long time ago. I don't have a sensibly working
53 * internet connection right now, so I rather don't mention names
54 * without double checking.
55 *
56 * This code here has been based partially based on mkdep.c, which
57 * says the following about its history:
58 *
59 * Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.
60 * This is a C version of syncdep.pl by Werner Almesberger.
61 *
62 *
63 * It is invoked as
64 *
65 * fixdep <depfile> <target> <cmdline>
66 *
67 * and will read the dependency file <depfile>
68 *
69 * The transformed dependency snipped is written to stdout.
70 *
71 * It first generates a line
72 *
73 * cmd_<target> = <cmdline>
74 *
75 * and then basically copies the .<target>.d file to stdout, in the
76 * process filtering out the dependency on autoconf.h and adding
77 * dependencies on include/config/MY_OPTION for every
78 * CONFIG_MY_OPTION encountered in any of the prerequisites.
79 *
80 * We don't even try to really parse the header files, but
81 * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will
82 * be picked up as well. It's not a problem with respect to
83 * correctness, since that can only give too many dependencies, thus
84 * we cannot miss a rebuild. Since people tend to not mention totally
85 * unrelated CONFIG_ options all over the place, it's not an
86 * efficiency problem either.
87 *
88 * (Note: it'd be easy to port over the complete mkdep state machine,
89 * but I don't think the added complexity is worth it)
90 */
91
92#include <sys/types.h>
93#include <sys/stat.h>
94#include <unistd.h>
95#include <fcntl.h>
96#include <string.h>
97#include <stdarg.h>
98#include <stdlib.h>
99#include <stdio.h>
100#include <ctype.h>
101
102static void usage(void)
103{
104 fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
105 exit(1);
106}
107
108/*
109 * In the intended usage of this program, the stdout is redirected to .*.cmd
110 * files. The return value of printf() must be checked to catch any error,
111 * e.g. "No space left on device".
112 */
113static void xprintf(const char *format, ...)
114{
115 va_list ap;
116 int ret;
117
118 va_start(ap, format);
119 ret = vprintf(format, ap);
120 if (ret < 0) {
121 perror("fixdep");
122 exit(1);
123 }
124 va_end(ap);
125}
126
127struct item {
128 struct item *next;
129 unsigned int len;
130 unsigned int hash;
131 char name[];
132};
133
134#define HASHSZ 256
135static struct item *hashtab[HASHSZ];
136
137static unsigned int strhash(const char *str, unsigned int sz)
138{
139 /* fnv32 hash */
140 unsigned int i, hash = 2166136261U;
141
142 for (i = 0; i < sz; i++)
143 hash = (hash ^ str[i]) * 0x01000193;
144 return hash;
145}
146
147/*
148 * Lookup a value in the configuration string.
149 */
150static int is_defined_config(const char *name, int len, unsigned int hash)
151{
152 struct item *aux;
153
154 for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) {
155 if (aux->hash == hash && aux->len == len &&
156 memcmp(aux->name, name, len) == 0)
157 return 1;
158 }
159 return 0;
160}
161
162/*
163 * Add a new value to the configuration string.
164 */
165static void define_config(const char *name, int len, unsigned int hash)
166{
167 struct item *aux = malloc(sizeof(*aux) + len);
168
169 if (!aux) {
170 perror("fixdep:malloc");
171 exit(1);
172 }
173 memcpy(aux->name, name, len);
174 aux->len = len;
175 aux->hash = hash;
176 aux->next = hashtab[hash % HASHSZ];
177 hashtab[hash % HASHSZ] = aux;
178}
179
180/*
181 * Record the use of a CONFIG_* word.
182 */
183static void use_config(const char *m, int slen)
184{
185 unsigned int hash = strhash(m, slen);
186
187 if (is_defined_config(m, slen, hash))
188 return;
189
190 define_config(m, slen, hash);
191 /* Print out a dependency path from a symbol name. */
192 xprintf(" $(wildcard include/config/%.*s) \\\n", slen, m);
193}
194
195/* test if s ends in sub */
196static int str_ends_with(const char *s, int slen, const char *sub)
197{
198 int sublen = strlen(sub);
199
200 if (sublen > slen)
201 return 0;
202
203 return !memcmp(s + slen - sublen, sub, sublen);
204}
205
206static void parse_config_file(const char *p)
207{
208 const char *q, *r;
209 const char *start = p;
210
211 while ((p = strstr(p, "CONFIG_"))) {
212 if (p > start && (isalnum(p[-1]) || p[-1] == '_')) {
213 p += 7;
214 continue;
215 }
216 p += 7;
217 q = p;
218 while (isalnum(*q) || *q == '_')
219 q++;
220 if (str_ends_with(p, q - p, "_MODULE"))
221 r = q - 7;
222 else
223 r = q;
224 if (r > p)
225 use_config(p, r - p);
226 p = q;
227 }
228}
229
230static void *read_file(const char *filename)
231{
232 struct stat st;
233 int fd;
234 char *buf;
235
236 fd = open(filename, O_RDONLY);
237 if (fd < 0) {
238 fprintf(stderr, "fixdep: error opening file: ");
239 perror(filename);
240 exit(2);
241 }
242 if (fstat(fd, &st) < 0) {
243 fprintf(stderr, "fixdep: error fstat'ing file: ");
244 perror(filename);
245 exit(2);
246 }
247 buf = malloc(st.st_size + 1);
248 if (!buf) {
249 perror("fixdep: malloc");
250 exit(2);
251 }
252 if (read(fd, buf, st.st_size) != st.st_size) {
253 perror("fixdep: read");
254 exit(2);
255 }
256 buf[st.st_size] = '\0';
257 close(fd);
258
259 return buf;
260}
261
262/* Ignore certain dependencies */
263static int is_ignored_file(const char *s, int len)
264{
265 return str_ends_with(s, len, "include/generated/autoconf.h") ||
266 str_ends_with(s, len, "include/generated/autoksyms.h");
267}
268
269/*
270 * Important: The below generated source_foo.o and deps_foo.o variable
271 * assignments are parsed not only by make, but also by the rather simple
272 * parser in scripts/mod/sumversion.c.
273 */
274static void parse_dep_file(char *m, const char *target)
275{
276 char *p;
277 int is_last, is_target;
278 int saw_any_target = 0;
279 int is_first_dep = 0;
280 void *buf;
281
282 while (1) {
283 /* Skip any "white space" */
284 while (*m == ' ' || *m == '\\' || *m == '\n')
285 m++;
286
287 if (!*m)
288 break;
289
290 /* Find next "white space" */
291 p = m;
292 while (*p && *p != ' ' && *p != '\\' && *p != '\n')
293 p++;
294 is_last = (*p == '\0');
295 /* Is the token we found a target name? */
296 is_target = (*(p-1) == ':');
297 /* Don't write any target names into the dependency file */
298 if (is_target) {
299 /* The /next/ file is the first dependency */
300 is_first_dep = 1;
301 } else if (!is_ignored_file(m, p - m)) {
302 *p = '\0';
303
304 /*
305 * Do not list the source file as dependency, so that
306 * kbuild is not confused if a .c file is rewritten
307 * into .S or vice versa. Storing it in source_* is
308 * needed for modpost to compute srcversions.
309 */
310 if (is_first_dep) {
311 /*
312 * If processing the concatenation of multiple
313 * dependency files, only process the first
314 * target name, which will be the original
315 * source name, and ignore any other target
316 * names, which will be intermediate temporary
317 * files.
318 */
319 if (!saw_any_target) {
320 saw_any_target = 1;
321 xprintf("source_%s := %s\n\n",
322 target, m);
323 xprintf("deps_%s := \\\n", target);
324 }
325 is_first_dep = 0;
326 } else {
327 xprintf(" %s \\\n", m);
328 }
329
330 buf = read_file(m);
331 parse_config_file(buf);
332 free(buf);
333 }
334
335 if (is_last)
336 break;
337
338 /*
339 * Start searching for next token immediately after the first
340 * "whitespace" character that follows this token.
341 */
342 m = p + 1;
343 }
344
345 if (!saw_any_target) {
346 fprintf(stderr, "fixdep: parse error; no targets found\n");
347 exit(1);
348 }
349
350 xprintf("\n%s: $(deps_%s)\n\n", target, target);
351 xprintf("$(deps_%s):\n", target);
352}
353
354int main(int argc, char *argv[])
355{
356 const char *depfile, *target, *cmdline;
357 void *buf;
358
359 if (argc != 4)
360 usage();
361
362 depfile = argv[1];
363 target = argv[2];
364 cmdline = argv[3];
365
366 xprintf("cmd_%s := %s\n\n", target, cmdline);
367
368 buf = read_file(depfile);
369 parse_dep_file(buf, target);
370 free(buf);
371
372 return 0;
373}