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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Sam Ravnborg264a2682009-10-18 00:49:24 +020019 * every file in the kernel includes autoconf.h.
Linus Torvalds1da177e2005-04-16 15:20:36 -070020 *
Sam Ravnborg264a2682009-10-18 00:49:24 +020021 * If the user re-runs make *config, autoconf.h will be
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 * 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
Sam Ravnborg264a2682009-10-18 00:49:24 +020027 * the dependency on autoconf.h by a dependency on every config
Linus Torvalds1da177e2005-04-16 15:20:36 -070028 * option which is mentioned in any of the listed prequisites.
29 *
Jan Beulichc21b1e42007-03-29 10:27:14 +010030 * 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 *
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
Sam Ravnborg264a2682009-10-18 00:49:24 +020076 * process filtering out the dependency on autoconf.h and adding
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 * 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
Nicolas Pitred8329e32016-02-12 15:00:50 -0500123int insert_extra_deps;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124char *target;
125char *depfile;
126char *cmdline;
127
Trevor Keith4356f482009-09-18 12:49:23 -0700128static void usage(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129{
Nicolas Pitred8329e32016-02-12 15:00:50 -0500130 fprintf(stderr, "Usage: fixdep [-e] <depfile> <target> <cmdline>\n");
131 fprintf(stderr, " -e insert extra dependencies given on stdin\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 exit(1);
133}
134
Sam Ravnborg4d99f932005-12-25 23:21:14 +0100135/*
136 * Print out the commandline prefixed with cmd_<target filename> :=
Jan Beulich6176aa92006-01-30 10:04:27 +0100137 */
Trevor Keith4356f482009-09-18 12:49:23 -0700138static void print_cmdline(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
Jan Beulich6176aa92006-01-30 10:04:27 +0100140 printf("cmd_%s := %s\n\n", target, cmdline);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141}
142
Nicolas Pitred8329e32016-02-12 15:00:50 -0500143/*
144 * Print out a dependency path from a symbol name
145 */
146static void print_config(const char *m, int slen)
147{
148 int c, i;
149
150 printf(" $(wildcard include/config/");
151 for (i = 0; i < slen; i++) {
152 c = m[i];
153 if (c == '_')
154 c = '/';
155 else
156 c = tolower(c);
157 putchar(c);
158 }
159 printf(".h) \\\n");
160}
161
162static void do_extra_deps(void)
163{
164 if (insert_extra_deps) {
165 char buf[80];
166 while(fgets(buf, sizeof(buf), stdin)) {
167 int len = strlen(buf);
168 if (len < 2 || buf[len-1] != '\n') {
169 fprintf(stderr, "fixdep: bad data on stdin\n");
170 exit(1);
171 }
172 print_config(buf, len-1);
173 }
174 }
175}
176
Eric Dumazet8af27e12010-11-09 16:29:27 +0100177struct item {
178 struct item *next;
179 unsigned int len;
180 unsigned int hash;
181 char name[0];
182};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183
Eric Dumazet8af27e12010-11-09 16:29:27 +0100184#define HASHSZ 256
185static struct item *hashtab[HASHSZ];
186
187static unsigned int strhash(const char *str, unsigned int sz)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188{
Eric Dumazet8af27e12010-11-09 16:29:27 +0100189 /* fnv32 hash */
190 unsigned int i, hash = 2166136261U;
191
192 for (i = 0; i < sz; i++)
193 hash = (hash ^ str[i]) * 0x01000193;
194 return hash;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195}
196
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197/*
198 * Lookup a value in the configuration string.
199 */
Eric Dumazet8af27e12010-11-09 16:29:27 +0100200static int is_defined_config(const char *name, int len, unsigned int hash)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201{
Eric Dumazet8af27e12010-11-09 16:29:27 +0100202 struct item *aux;
203
204 for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) {
205 if (aux->hash == hash && aux->len == len &&
206 memcmp(aux->name, name, len) == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 return 1;
208 }
209 return 0;
210}
211
212/*
213 * Add a new value to the configuration string.
214 */
Eric Dumazet8af27e12010-11-09 16:29:27 +0100215static void define_config(const char *name, int len, unsigned int hash)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216{
Eric Dumazet8af27e12010-11-09 16:29:27 +0100217 struct item *aux = malloc(sizeof(*aux) + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218
Eric Dumazet8af27e12010-11-09 16:29:27 +0100219 if (!aux) {
220 perror("fixdep:malloc");
221 exit(1);
222 }
223 memcpy(aux->name, name, len);
224 aux->len = len;
225 aux->hash = hash;
226 aux->next = hashtab[hash % HASHSZ];
227 hashtab[hash % HASHSZ] = aux;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228}
229
230/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 * Record the use of a CONFIG_* word.
232 */
Eric Dumazet8af27e12010-11-09 16:29:27 +0100233static void use_config(const char *m, int slen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234{
Eric Dumazet8af27e12010-11-09 16:29:27 +0100235 unsigned int hash = strhash(m, slen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
Eric Dumazet8af27e12010-11-09 16:29:27 +0100237 if (is_defined_config(m, slen, hash))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 return;
239
Eric Dumazet8af27e12010-11-09 16:29:27 +0100240 define_config(m, slen, hash);
Nicolas Pitred8329e32016-02-12 15:00:50 -0500241 print_config(m, slen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242}
243
Eric Dumazet8af27e12010-11-09 16:29:27 +0100244static void parse_config_file(const char *map, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245{
Eric Dumazet8af27e12010-11-09 16:29:27 +0100246 const int *end = (const int *) (map + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 /* start at +1, so that p can never be < map */
Eric Dumazet8af27e12010-11-09 16:29:27 +0100248 const int *m = (const int *) map + 1;
249 const char *p, *q;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250
251 for (; m < end; m++) {
J.A. Magallon48b9d032005-06-25 14:59:22 -0700252 if (*m == INT_CONF) { p = (char *) m ; goto conf; }
253 if (*m == INT_ONFI) { p = (char *) m-1; goto conf; }
254 if (*m == INT_NFIG) { p = (char *) m-2; goto conf; }
255 if (*m == INT_FIG_) { p = (char *) m-3; goto conf; }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 continue;
257 conf:
258 if (p > map + len - 7)
259 continue;
260 if (memcmp(p, "CONFIG_", 7))
261 continue;
Masahiro Yamadad7211092015-07-24 14:18:45 +0900262 p += 7;
263 for (q = p; q < map + len; q++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 if (!(isalnum(*q) || *q == '_'))
265 goto found;
266 }
267 continue;
268
269 found:
Jan Beulichc21b1e42007-03-29 10:27:14 +0100270 if (!memcmp(q - 7, "_MODULE", 7))
271 q -= 7;
Masahiro Yamadad7211092015-07-24 14:18:45 +0900272 if (q - p < 0)
Andy Green04c58f82007-05-02 12:49:06 +0100273 continue;
Masahiro Yamadad7211092015-07-24 14:18:45 +0900274 use_config(p, q - p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 }
276}
277
Nicolas Pitred8329e32016-02-12 15:00:50 -0500278/* test if s ends in sub */
Nicolas Iooss4c835b52015-11-18 19:07:15 +0100279static int strrcmp(const char *s, const char *sub)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280{
281 int slen = strlen(s);
282 int sublen = strlen(sub);
283
284 if (sublen > slen)
285 return 1;
286
287 return memcmp(s + slen - sublen, sub, sublen);
288}
289
Eric Dumazet8af27e12010-11-09 16:29:27 +0100290static void do_config_file(const char *filename)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291{
292 struct stat st;
293 int fd;
294 void *map;
295
296 fd = open(filename, O_RDONLY);
297 if (fd < 0) {
Ben Gamaria3ba8112010-12-22 13:30:14 -0500298 fprintf(stderr, "fixdep: error opening config file: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 perror(filename);
300 exit(2);
301 }
Tom Rini46fe94a2015-12-07 16:26:08 -0500302 if (fstat(fd, &st) < 0) {
303 fprintf(stderr, "fixdep: error fstat'ing config file: ");
304 perror(filename);
305 exit(2);
306 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 if (st.st_size == 0) {
308 close(fd);
309 return;
310 }
311 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
312 if ((long) map == -1) {
313 perror("fixdep: mmap");
314 close(fd);
315 return;
316 }
317
318 parse_config_file(map, st.st_size);
319
320 munmap(map, st.st_size);
321
322 close(fd);
323}
324
Michal Marek7840fea2011-03-11 22:34:47 +0100325/*
326 * Important: The below generated source_foo.o and deps_foo.o variable
327 * assignments are parsed not only by make, but also by the rather simple
328 * parser in scripts/mod/sumversion.c.
329 */
Trevor Keith4356f482009-09-18 12:49:23 -0700330static void parse_dep_file(void *map, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331{
J.A. Magallon48b9d032005-06-25 14:59:22 -0700332 char *m = map;
333 char *end = m + len;
334 char *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 char s[PATH_MAX];
Stephen Warren2ab8a992013-03-06 10:27:45 -0700336 int is_target;
337 int saw_any_target = 0;
338 int is_first_dep = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 while (m < end) {
Stephen Warren2ab8a992013-03-06 10:27:45 -0700341 /* Skip any "white space" */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
343 m++;
Stephen Warren2ab8a992013-03-06 10:27:45 -0700344 /* Find next "white space" */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 p = m;
Stephen Warren2ab8a992013-03-06 10:27:45 -0700346 while (p < end && *p != ' ' && *p != '\\' && *p != '\n')
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 p++;
Stephen Warren2ab8a992013-03-06 10:27:45 -0700348 /* Is the token we found a target name? */
349 is_target = (*(p-1) == ':');
350 /* Don't write any target names into the dependency file */
351 if (is_target) {
352 /* The /next/ file is the first dependency */
353 is_first_dep = 1;
354 } else {
355 /* Save this token/filename */
356 memcpy(s, m, p-m);
357 s[p - m] = 0;
358
359 /* Ignore certain dependencies */
360 if (strrcmp(s, "include/generated/autoconf.h") &&
Nicolas Pitrec1a95fd2016-01-22 13:41:57 -0500361 strrcmp(s, "include/generated/autoksyms.h") &&
Stephen Warren2ab8a992013-03-06 10:27:45 -0700362 strrcmp(s, "arch/um/include/uml-config.h") &&
363 strrcmp(s, "include/linux/kconfig.h") &&
364 strrcmp(s, ".ver")) {
365 /*
366 * Do not list the source file as dependency,
367 * so that kbuild is not confused if a .c file
368 * is rewritten into .S or vice versa. Storing
369 * it in source_* is needed for modpost to
370 * compute srcversions.
371 */
372 if (is_first_dep) {
373 /*
374 * If processing the concatenation of
375 * multiple dependency files, only
376 * process the first target name, which
377 * will be the original source name,
378 * and ignore any other target names,
379 * which will be intermediate temporary
380 * files.
381 */
382 if (!saw_any_target) {
383 saw_any_target = 1;
384 printf("source_%s := %s\n\n",
385 target, s);
386 printf("deps_%s := \\\n",
387 target);
388 }
389 is_first_dep = 0;
390 } else
391 printf(" %s \\\n", s);
392 do_config_file(s);
393 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 }
Stephen Warren2ab8a992013-03-06 10:27:45 -0700395 /*
396 * Start searching for next token immediately after the first
397 * "whitespace" character that follows this token.
398 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 m = p + 1;
400 }
Stephen Warren2ab8a992013-03-06 10:27:45 -0700401
402 if (!saw_any_target) {
403 fprintf(stderr, "fixdep: parse error; no targets found\n");
404 exit(1);
405 }
406
Nicolas Pitred8329e32016-02-12 15:00:50 -0500407 do_extra_deps();
408
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 printf("\n%s: $(deps_%s)\n\n", target, target);
410 printf("$(deps_%s):\n", target);
411}
412
Trevor Keith4356f482009-09-18 12:49:23 -0700413static void print_deps(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414{
415 struct stat st;
416 int fd;
417 void *map;
418
419 fd = open(depfile, O_RDONLY);
420 if (fd < 0) {
Ben Gamaria3ba8112010-12-22 13:30:14 -0500421 fprintf(stderr, "fixdep: error opening depfile: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 perror(depfile);
423 exit(2);
424 }
Ben Gamaria3ba8112010-12-22 13:30:14 -0500425 if (fstat(fd, &st) < 0) {
Masahiro Yamadabb66fc62014-06-10 19:08:13 +0900426 fprintf(stderr, "fixdep: error fstat'ing depfile: ");
427 perror(depfile);
428 exit(2);
429 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 if (st.st_size == 0) {
431 fprintf(stderr,"fixdep: %s is empty\n",depfile);
432 close(fd);
433 return;
434 }
435 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
436 if ((long) map == -1) {
437 perror("fixdep: mmap");
438 close(fd);
439 return;
440 }
441
442 parse_dep_file(map, st.st_size);
443
444 munmap(map, st.st_size);
445
446 close(fd);
447}
448
Trevor Keith4356f482009-09-18 12:49:23 -0700449static void traps(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450{
451 static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
Amerigo Wangd067aa72009-06-10 12:48:23 -0700452 int *p = (int *)test;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453
Amerigo Wangd067aa72009-06-10 12:48:23 -0700454 if (*p != INT_CONF) {
Masanari Iida8a168ca2012-12-29 02:00:09 +0900455 fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianness? %#x\n",
Amerigo Wangd067aa72009-06-10 12:48:23 -0700456 *p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 exit(2);
458 }
459}
460
461int main(int argc, char *argv[])
462{
463 traps();
464
Nicolas Pitred8329e32016-02-12 15:00:50 -0500465 if (argc == 5 && !strcmp(argv[1], "-e")) {
466 insert_extra_deps = 1;
467 argv++;
468 } else if (argc != 4)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 usage();
470
471 depfile = argv[1];
472 target = argv[2];
473 cmdline = argv[3];
474
475 print_cmdline();
476 print_deps();
477
478 return 0;
479}