source: branches/2.2.9/mindi-busybox/scripts/basic/fixdep.c @ 2725

Last change on this file since 2725 was 2725, checked in by Bruno Cornec, 9 years ago
  • Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3
  • Property svn:eol-style set to native
File size: 9.7 KB
Line 
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
124char *target;
125char *depfile;
126char *cmdline;
127
128void 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 */
138void print_cmdline(void)
139{
140    printf("cmd_%s := %s\n\n", target, cmdline);
141}
142
143char * str_config  = NULL;
144int    size_config = 0;
145int    len_config  = 0;
146
147/*
148 * Grow the configuration string to a desired length.
149 * Usually the first growth is plenty.
150 */
151void 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 */
167int 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 */
183void 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 */
195void clear_config(void)
196{
197    len_config = 0;
198    define_config("", 0);
199}
200
201/*
202 * Record the use of a CONFIG_* word.
203 */
204void use_config(char *m, int slen)
205{
206    char *s = alloca(slen+1);
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
225void parse_config_file(char *map, size_t len)
226{
227    /* modified for bbox */
228    char *end_3 = map + len - 3; /* 3 == length of "IF_" */
229    char *end_7 = map + len - 7;
230    char *p = map;
231    char *q;
232    int off;
233
234    for (; p <= end_3; p++) {
235        /* Find next identifier's beginning */
236        if (!(isalnum(*p) || *p == '_'))
237            continue;
238
239        /* Check it */
240        if (p < end_7 && p[6] == '_') {
241            if (!memcmp(p, "CONFIG", 6)) goto conf7;
242            if (!memcmp(p, "ENABLE", 6)) goto conf7;
243            if (!memcmp(p, "IF_NOT", 6)) goto conf7;
244        }
245        /* we have at least 3 chars because of p <= end_3 */
246        /*if (!memcmp(p, "IF_", 3)) ...*/
247        if (p[0] == 'I' && p[1] == 'F' && p[2] == '_') {
248            off = 3;
249            goto conf;
250        }
251
252        /* This identifier is not interesting, skip it */
253        while (p <= end_3 && (isalnum(*p) || *p == '_'))
254            p++;
255        continue;
256
257    conf7:  off = 7;
258    conf:
259        p += off;
260        for (q = p; q < end_3+3; q++) {
261            if (!(isalnum(*q) || *q == '_'))
262                break;
263        }
264        if (q != p) {
265            use_config(p, q-p);
266        }
267    }
268}
269
270/* test is s ends in sub */
271int strrcmp(char *s, char *sub)
272{
273    int slen = strlen(s);
274    int sublen = strlen(sub);
275
276    if (sublen > slen)
277        return 1;
278
279    return memcmp(s + slen - sublen, sub, sublen);
280}
281
282void do_config_file(char *filename)
283{
284    struct stat st;
285    int fd;
286    void *map;
287
288    fd = open(filename, O_RDONLY);
289    if (fd < 0) {
290        fprintf(stderr, "fixdep: ");
291        perror(filename);
292        exit(2);
293    }
294    fstat(fd, &st);
295    if (st.st_size == 0) {
296        close(fd);
297        return;
298    }
299    map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
300    if ((long) map == -1) {
301        perror("fixdep: mmap");
302        close(fd);
303        return;
304    }
305
306    parse_config_file(map, st.st_size);
307
308    munmap(map, st.st_size);
309
310    close(fd);
311}
312
313void parse_dep_file(void *map, size_t len)
314{
315    char *m = map;
316    char *end = m + len;
317    char *p;
318    char *s = alloca(len);
319
320    p = memchr(m, ':', len);
321    if (!p) {
322        fprintf(stderr, "fixdep: parse error\n");
323        exit(1);
324    }
325    memcpy(s, m, p-m); s[p-m] = 0;
326    printf("deps_%s := \\\n", target);
327    m = p+1;
328
329    clear_config();
330
331    while (m < end) {
332        while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
333            m++;
334        p = m;
335        while (p < end && *p != ' ') p++;
336        if (p == end) {
337            do p--; while (!isalnum(*p));
338            p++;
339        }
340        memcpy(s, m, p-m); s[p-m] = 0;
341        if (strrcmp(s, "include/autoconf.h") &&
342            strrcmp(s, "arch/um/include/uml-config.h") &&
343            strrcmp(s, ".ver")) {
344            printf("  %s \\\n", s);
345            do_config_file(s);
346        }
347        m = p + 1;
348    }
349    printf("\n%s: $(deps_%s)\n\n", target, target);
350    printf("$(deps_%s):\n", target);
351}
352
353void print_deps(void)
354{
355    struct stat st;
356    int fd;
357    void *map;
358
359    fd = open(depfile, O_RDONLY);
360    if (fd < 0) {
361        fprintf(stderr, "fixdep: ");
362        perror(depfile);
363        exit(2);
364    }
365    fstat(fd, &st);
366    if (st.st_size == 0) {
367        fprintf(stderr,"fixdep: %s is empty\n",depfile);
368        close(fd);
369        return;
370    }
371    map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
372    if ((long) map == -1) {
373        perror("fixdep: mmap");
374        close(fd);
375        return;
376    }
377
378    parse_dep_file(map, st.st_size);
379
380    munmap(map, st.st_size);
381
382    close(fd);
383}
384
385void traps(void)
386{
387/* bbox: not needed
388    static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
389
390    if (*(int *)test != INT_CONF) {
391        fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
392            *(int *)test);
393        exit(2);
394    }
395*/
396}
397
398int main(int argc, char **argv)
399{
400    traps();
401
402    if (argc != 4)
403        usage();
404
405    depfile = argv[1];
406    target = argv[2];
407    cmdline = argv[3];
408
409    print_cmdline();
410    print_deps();
411
412    return 0;
413}
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