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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
Markus Heidelberg7d3392e2009-06-12 01:02:35 +020019 * every file in the kernel includes <linux/autoconf.h>.
Linus Torvalds1da177e2005-04-16 15:20:36 -070020 *
21 * If the user re-runs make *config, linux/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 linux/autoconf.h by a dependency on every config
28 * 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
76 * process filtering out the dependency on linux/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
Trevor Keith4356f482009-09-18 12:49:23 -0700127static void usage(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128{
129 fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
130 exit(1);
131}
132
Sam Ravnborg4d99f932005-12-25 23:21:14 +0100133/*
134 * Print out the commandline prefixed with cmd_<target filename> :=
Jan Beulich6176aa92006-01-30 10:04:27 +0100135 */
Trevor Keith4356f482009-09-18 12:49:23 -0700136static void print_cmdline(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137{
Jan Beulich6176aa92006-01-30 10:04:27 +0100138 printf("cmd_%s := %s\n\n", target, cmdline);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139}
140
141char * str_config = NULL;
142int size_config = 0;
143int len_config = 0;
144
145/*
146 * Grow the configuration string to a desired length.
147 * Usually the first growth is plenty.
148 */
Trevor Keith4356f482009-09-18 12:49:23 -0700149static void grow_config(int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150{
151 while (len_config + len > size_config) {
152 if (size_config == 0)
153 size_config = 2048;
154 str_config = realloc(str_config, size_config *= 2);
155 if (str_config == NULL)
156 { perror("fixdep:malloc"); exit(1); }
157 }
158}
159
160
161
162/*
163 * Lookup a value in the configuration string.
164 */
Trevor Keith4356f482009-09-18 12:49:23 -0700165static int is_defined_config(const char * name, int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166{
167 const char * pconfig;
168 const char * plast = str_config + len_config - len;
169 for ( pconfig = str_config + 1; pconfig < plast; pconfig++ ) {
170 if (pconfig[ -1] == '\n'
171 && pconfig[len] == '\n'
172 && !memcmp(pconfig, name, len))
173 return 1;
174 }
175 return 0;
176}
177
178/*
179 * Add a new value to the configuration string.
180 */
Trevor Keith4356f482009-09-18 12:49:23 -0700181static void define_config(const char * name, int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182{
183 grow_config(len + 1);
184
185 memcpy(str_config+len_config, name, len);
186 len_config += len;
187 str_config[len_config++] = '\n';
188}
189
190/*
191 * Clear the set of configuration strings.
192 */
Trevor Keith4356f482009-09-18 12:49:23 -0700193static void clear_config(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194{
195 len_config = 0;
196 define_config("", 0);
197}
198
199/*
200 * Record the use of a CONFIG_* word.
201 */
Trevor Keith4356f482009-09-18 12:49:23 -0700202static void use_config(char *m, int slen)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203{
204 char s[PATH_MAX];
205 char *p;
206
207 if (is_defined_config(m, slen))
208 return;
209
210 define_config(m, slen);
211
212 memcpy(s, m, slen); s[slen] = 0;
213
214 for (p = s; p < s + slen; p++) {
215 if (*p == '_')
216 *p = '/';
217 else
J.A. Magallon48b9d032005-06-25 14:59:22 -0700218 *p = tolower((int)*p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 }
220 printf(" $(wildcard include/config/%s.h) \\\n", s);
221}
222
Trevor Keith4356f482009-09-18 12:49:23 -0700223static void parse_config_file(char *map, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224{
225 int *end = (int *) (map + len);
226 /* start at +1, so that p can never be < map */
227 int *m = (int *) map + 1;
J.A. Magallon48b9d032005-06-25 14:59:22 -0700228 char *p, *q;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
230 for (; m < end; m++) {
J.A. Magallon48b9d032005-06-25 14:59:22 -0700231 if (*m == INT_CONF) { p = (char *) m ; goto conf; }
232 if (*m == INT_ONFI) { p = (char *) m-1; goto conf; }
233 if (*m == INT_NFIG) { p = (char *) m-2; goto conf; }
234 if (*m == INT_FIG_) { p = (char *) m-3; goto conf; }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 continue;
236 conf:
237 if (p > map + len - 7)
238 continue;
239 if (memcmp(p, "CONFIG_", 7))
240 continue;
241 for (q = p + 7; q < map + len; q++) {
242 if (!(isalnum(*q) || *q == '_'))
243 goto found;
244 }
245 continue;
246
247 found:
Jan Beulichc21b1e42007-03-29 10:27:14 +0100248 if (!memcmp(q - 7, "_MODULE", 7))
249 q -= 7;
Andy Green04c58f82007-05-02 12:49:06 +0100250 if( (q-p-7) < 0 )
251 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 use_config(p+7, q-p-7);
253 }
254}
255
256/* test is s ends in sub */
Trevor Keith4356f482009-09-18 12:49:23 -0700257static int strrcmp(char *s, char *sub)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258{
259 int slen = strlen(s);
260 int sublen = strlen(sub);
261
262 if (sublen > slen)
263 return 1;
264
265 return memcmp(s + slen - sublen, sub, sublen);
266}
267
Trevor Keith4356f482009-09-18 12:49:23 -0700268static void do_config_file(char *filename)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269{
270 struct stat st;
271 int fd;
272 void *map;
273
274 fd = open(filename, O_RDONLY);
275 if (fd < 0) {
276 fprintf(stderr, "fixdep: ");
277 perror(filename);
278 exit(2);
279 }
280 fstat(fd, &st);
281 if (st.st_size == 0) {
282 close(fd);
283 return;
284 }
285 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
286 if ((long) map == -1) {
287 perror("fixdep: mmap");
288 close(fd);
289 return;
290 }
291
292 parse_config_file(map, st.st_size);
293
294 munmap(map, st.st_size);
295
296 close(fd);
297}
298
Trevor Keith4356f482009-09-18 12:49:23 -0700299static void parse_dep_file(void *map, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300{
J.A. Magallon48b9d032005-06-25 14:59:22 -0700301 char *m = map;
302 char *end = m + len;
303 char *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 char s[PATH_MAX];
305
306 p = strchr(m, ':');
307 if (!p) {
308 fprintf(stderr, "fixdep: parse error\n");
309 exit(1);
310 }
311 memcpy(s, m, p-m); s[p-m] = 0;
312 printf("deps_%s := \\\n", target);
313 m = p+1;
314
315 clear_config();
316
317 while (m < end) {
318 while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
319 m++;
320 p = m;
321 while (p < end && *p != ' ') p++;
322 if (p == end) {
323 do p--; while (!isalnum(*p));
324 p++;
325 }
326 memcpy(s, m, p-m); s[p-m] = 0;
327 if (strrcmp(s, "include/linux/autoconf.h") &&
328 strrcmp(s, "arch/um/include/uml-config.h") &&
329 strrcmp(s, ".ver")) {
330 printf(" %s \\\n", s);
331 do_config_file(s);
332 }
333 m = p + 1;
334 }
335 printf("\n%s: $(deps_%s)\n\n", target, target);
336 printf("$(deps_%s):\n", target);
337}
338
Trevor Keith4356f482009-09-18 12:49:23 -0700339static void print_deps(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340{
341 struct stat st;
342 int fd;
343 void *map;
344
345 fd = open(depfile, O_RDONLY);
346 if (fd < 0) {
347 fprintf(stderr, "fixdep: ");
348 perror(depfile);
349 exit(2);
350 }
351 fstat(fd, &st);
352 if (st.st_size == 0) {
353 fprintf(stderr,"fixdep: %s is empty\n",depfile);
354 close(fd);
355 return;
356 }
357 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
358 if ((long) map == -1) {
359 perror("fixdep: mmap");
360 close(fd);
361 return;
362 }
363
364 parse_dep_file(map, st.st_size);
365
366 munmap(map, st.st_size);
367
368 close(fd);
369}
370
Trevor Keith4356f482009-09-18 12:49:23 -0700371static void traps(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372{
373 static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
Amerigo Wangd067aa72009-06-10 12:48:23 -0700374 int *p = (int *)test;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375
Amerigo Wangd067aa72009-06-10 12:48:23 -0700376 if (*p != INT_CONF) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
Amerigo Wangd067aa72009-06-10 12:48:23 -0700378 *p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 exit(2);
380 }
381}
382
383int main(int argc, char *argv[])
384{
385 traps();
386
387 if (argc != 4)
388 usage();
389
390 depfile = argv[1];
391 target = argv[2];
392 cmdline = argv[3];
393
394 print_cmdline();
395 print_deps();
396
397 return 0;
398}