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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 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 * savedcmd_<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 <stdbool.h>
98#include <stdlib.h>
99#include <stdio.h>
100#include <ctype.h>
101
102#include <xalloc.h>
103
104static void usage(void)
105{
106 fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
107 exit(1);
108}
109
110struct item {
111 struct item *next;
112 unsigned int len;
113 unsigned int hash;
114 char name[];
115};
116
117#define HASHSZ 256
118static struct item *config_hashtab[HASHSZ], *file_hashtab[HASHSZ];
119
120static unsigned int strhash(const char *str, unsigned int sz)
121{
122 /* fnv32 hash */
123 unsigned int i, hash = 2166136261U;
124
125 for (i = 0; i < sz; i++)
126 hash = (hash ^ str[i]) * 0x01000193;
127 return hash;
128}
129
130/*
131 * Add a new value to the configuration string.
132 */
133static void add_to_hashtable(const char *name, int len, unsigned int hash,
134 struct item *hashtab[])
135{
136 struct item *aux;
137
138 aux = xmalloc(sizeof(*aux) + len);
139 memcpy(aux->name, name, len);
140 aux->len = len;
141 aux->hash = hash;
142 aux->next = hashtab[hash % HASHSZ];
143 hashtab[hash % HASHSZ] = aux;
144}
145
146/*
147 * Lookup a string in the hash table. If found, just return true.
148 * If not, add it to the hashtable and return false.
149 */
150static bool in_hashtable(const char *name, int len, struct item *hashtab[])
151{
152 struct item *aux;
153 unsigned int hash = strhash(name, len);
154
155 for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) {
156 if (aux->hash == hash && aux->len == len &&
157 memcmp(aux->name, name, len) == 0)
158 return true;
159 }
160
161 add_to_hashtable(name, len, hash, hashtab);
162
163 return false;
164}
165
166/*
167 * Record the use of a CONFIG_* word.
168 */
169static void use_config(const char *m, int slen)
170{
171 if (in_hashtable(m, slen, config_hashtab))
172 return;
173
174 /* Print out a dependency path from a symbol name. */
175 printf(" $(wildcard include/config/%.*s) \\\n", slen, m);
176}
177
178/* test if s ends in sub */
179static int str_ends_with(const char *s, int slen, const char *sub)
180{
181 int sublen = strlen(sub);
182
183 if (sublen > slen)
184 return 0;
185
186 return !memcmp(s + slen - sublen, sub, sublen);
187}
188
189static void parse_config_file(const char *p)
190{
191 const char *q, *r;
192 const char *start = p;
193
194 while ((p = strstr(p, "CONFIG_"))) {
195 if (p > start && (isalnum(p[-1]) || p[-1] == '_')) {
196 p += 7;
197 continue;
198 }
199 p += 7;
200 q = p;
201 while (isalnum(*q) || *q == '_')
202 q++;
203 if (str_ends_with(p, q - p, "_MODULE"))
204 r = q - 7;
205 else
206 r = q;
207 if (r > p)
208 use_config(p, r - p);
209 p = q;
210 }
211}
212
213static void *read_file(const char *filename)
214{
215 struct stat st;
216 int fd;
217 char *buf;
218
219 fd = open(filename, O_RDONLY);
220 if (fd < 0) {
221 fprintf(stderr, "fixdep: error opening file: ");
222 perror(filename);
223 exit(2);
224 }
225 if (fstat(fd, &st) < 0) {
226 fprintf(stderr, "fixdep: error fstat'ing file: ");
227 perror(filename);
228 exit(2);
229 }
230 buf = xmalloc(st.st_size + 1);
231 if (read(fd, buf, st.st_size) != st.st_size) {
232 perror("fixdep: read");
233 exit(2);
234 }
235 buf[st.st_size] = '\0';
236 close(fd);
237
238 return buf;
239}
240
241/* Ignore certain dependencies */
242static int is_ignored_file(const char *s, int len)
243{
244 return str_ends_with(s, len, "include/generated/autoconf.h");
245}
246
247/* Do not parse these files */
248static int is_no_parse_file(const char *s, int len)
249{
250 /* rustc may list binary files in dep-info */
251 return str_ends_with(s, len, ".rlib") ||
252 str_ends_with(s, len, ".rmeta") ||
253 str_ends_with(s, len, ".so");
254}
255
256/*
257 * Important: The below generated source_foo.o and deps_foo.o variable
258 * assignments are parsed not only by make, but also by the rather simple
259 * parser in scripts/mod/sumversion.c.
260 */
261static void parse_dep_file(char *p, const char *target)
262{
263 bool saw_any_target = false;
264 bool is_target = true;
265 bool is_source = false;
266 bool need_parse;
267 char *q, saved_c;
268
269 while (*p) {
270 /* handle some special characters first. */
271 switch (*p) {
272 case '#':
273 /*
274 * skip comments.
275 * rustc may emit comments to dep-info.
276 */
277 p++;
278 while (*p != '\0' && *p != '\n') {
279 /*
280 * escaped newlines continue the comment across
281 * multiple lines.
282 */
283 if (*p == '\\')
284 p++;
285 p++;
286 }
287 continue;
288 case ' ':
289 case '\t':
290 /* skip whitespaces */
291 p++;
292 continue;
293 case '\\':
294 /*
295 * backslash/newline combinations continue the
296 * statement. Skip it just like a whitespace.
297 */
298 if (*(p + 1) == '\n') {
299 p += 2;
300 continue;
301 }
302 break;
303 case '\n':
304 /*
305 * Makefiles use a line-based syntax, where the newline
306 * is the end of a statement. After seeing a newline,
307 * we expect the next token is a target.
308 */
309 p++;
310 is_target = true;
311 continue;
312 case ':':
313 /*
314 * assume the first dependency after a colon as the
315 * source file.
316 */
317 p++;
318 is_target = false;
319 is_source = true;
320 continue;
321 }
322
323 /* find the end of the token */
324 q = p;
325 while (*q != ' ' && *q != '\t' && *q != '\n' && *q != '#' && *q != ':') {
326 if (*q == '\\') {
327 /*
328 * backslash/newline combinations work like as
329 * a whitespace, so this is the end of token.
330 */
331 if (*(q + 1) == '\n')
332 break;
333
334 /* escaped special characters */
335 if (*(q + 1) == '#' || *(q + 1) == ':') {
336 memmove(p + 1, p, q - p);
337 p++;
338 }
339
340 q++;
341 }
342
343 if (*q == '\0')
344 break;
345 q++;
346 }
347
348 /* Just discard the target */
349 if (is_target) {
350 p = q;
351 continue;
352 }
353
354 saved_c = *q;
355 *q = '\0';
356 need_parse = false;
357
358 /*
359 * Do not list the source file as dependency, so that kbuild is
360 * not confused if a .c file is rewritten into .S or vice versa.
361 * Storing it in source_* is needed for modpost to compute
362 * srcversions.
363 */
364 if (is_source) {
365 /*
366 * The DT build rule concatenates multiple dep files.
367 * When processing them, only process the first source
368 * name, which will be the original one, and ignore any
369 * other source names, which will be intermediate
370 * temporary files.
371 *
372 * rustc emits the same dependency list for each
373 * emission type. It is enough to list the source name
374 * just once.
375 */
376 if (!saw_any_target) {
377 saw_any_target = true;
378 printf("source_%s := %s\n\n", target, p);
379 printf("deps_%s := \\\n", target);
380 need_parse = true;
381 }
382 } else if (!is_ignored_file(p, q - p) &&
383 !in_hashtable(p, q - p, file_hashtab)) {
384 printf(" %s \\\n", p);
385 need_parse = true;
386 }
387
388 if (need_parse && !is_no_parse_file(p, q - p)) {
389 void *buf;
390
391 buf = read_file(p);
392 parse_config_file(buf);
393 free(buf);
394 }
395
396 is_source = false;
397 *q = saved_c;
398 p = q;
399 }
400
401 if (!saw_any_target) {
402 fprintf(stderr, "fixdep: parse error; no targets found\n");
403 exit(1);
404 }
405
406 printf("\n%s: $(deps_%s)\n\n", target, target);
407 printf("$(deps_%s):\n", target);
408}
409
410int main(int argc, char *argv[])
411{
412 const char *depfile, *target, *cmdline;
413 void *buf;
414
415 if (argc != 4)
416 usage();
417
418 depfile = argv[1];
419 target = argv[2];
420 cmdline = argv[3];
421
422 printf("savedcmd_%s := %s\n\n", target, cmdline);
423
424 buf = read_file(depfile);
425 parse_dep_file(buf, target);
426 free(buf);
427
428 fflush(stdout);
429
430 /*
431 * In the intended usage, the stdout is redirected to .*.cmd files.
432 * Call ferror() to catch errors such as "No space left on device".
433 */
434 if (ferror(stdout)) {
435 fprintf(stderr, "fixdep: not all data was written to the output\n");
436 exit(1);
437 }
438
439 return 0;
440}
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 * savedcmd_<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 <stdbool.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
108struct item {
109 struct item *next;
110 unsigned int len;
111 unsigned int hash;
112 char name[];
113};
114
115#define HASHSZ 256
116static struct item *config_hashtab[HASHSZ], *file_hashtab[HASHSZ];
117
118static unsigned int strhash(const char *str, unsigned int sz)
119{
120 /* fnv32 hash */
121 unsigned int i, hash = 2166136261U;
122
123 for (i = 0; i < sz; i++)
124 hash = (hash ^ str[i]) * 0x01000193;
125 return hash;
126}
127
128/*
129 * Add a new value to the configuration string.
130 */
131static void add_to_hashtable(const char *name, int len, unsigned int hash,
132 struct item *hashtab[])
133{
134 struct item *aux = malloc(sizeof(*aux) + len);
135
136 if (!aux) {
137 perror("fixdep:malloc");
138 exit(1);
139 }
140 memcpy(aux->name, name, len);
141 aux->len = len;
142 aux->hash = hash;
143 aux->next = hashtab[hash % HASHSZ];
144 hashtab[hash % HASHSZ] = aux;
145}
146
147/*
148 * Lookup a string in the hash table. If found, just return true.
149 * If not, add it to the hashtable and return false.
150 */
151static bool in_hashtable(const char *name, int len, struct item *hashtab[])
152{
153 struct item *aux;
154 unsigned int hash = strhash(name, len);
155
156 for (aux = hashtab[hash % HASHSZ]; aux; aux = aux->next) {
157 if (aux->hash == hash && aux->len == len &&
158 memcmp(aux->name, name, len) == 0)
159 return true;
160 }
161
162 add_to_hashtable(name, len, hash, hashtab);
163
164 return false;
165}
166
167/*
168 * Record the use of a CONFIG_* word.
169 */
170static void use_config(const char *m, int slen)
171{
172 if (in_hashtable(m, slen, config_hashtab))
173 return;
174
175 /* Print out a dependency path from a symbol name. */
176 printf(" $(wildcard include/config/%.*s) \\\n", slen, m);
177}
178
179/* test if s ends in sub */
180static int str_ends_with(const char *s, int slen, const char *sub)
181{
182 int sublen = strlen(sub);
183
184 if (sublen > slen)
185 return 0;
186
187 return !memcmp(s + slen - sublen, sub, sublen);
188}
189
190static void parse_config_file(const char *p)
191{
192 const char *q, *r;
193 const char *start = p;
194
195 while ((p = strstr(p, "CONFIG_"))) {
196 if (p > start && (isalnum(p[-1]) || p[-1] == '_')) {
197 p += 7;
198 continue;
199 }
200 p += 7;
201 q = p;
202 while (isalnum(*q) || *q == '_')
203 q++;
204 if (str_ends_with(p, q - p, "_MODULE"))
205 r = q - 7;
206 else
207 r = q;
208 if (r > p)
209 use_config(p, r - p);
210 p = q;
211 }
212}
213
214static void *read_file(const char *filename)
215{
216 struct stat st;
217 int fd;
218 char *buf;
219
220 fd = open(filename, O_RDONLY);
221 if (fd < 0) {
222 fprintf(stderr, "fixdep: error opening file: ");
223 perror(filename);
224 exit(2);
225 }
226 if (fstat(fd, &st) < 0) {
227 fprintf(stderr, "fixdep: error fstat'ing file: ");
228 perror(filename);
229 exit(2);
230 }
231 buf = malloc(st.st_size + 1);
232 if (!buf) {
233 perror("fixdep: malloc");
234 exit(2);
235 }
236 if (read(fd, buf, st.st_size) != st.st_size) {
237 perror("fixdep: read");
238 exit(2);
239 }
240 buf[st.st_size] = '\0';
241 close(fd);
242
243 return buf;
244}
245
246/* Ignore certain dependencies */
247static int is_ignored_file(const char *s, int len)
248{
249 return str_ends_with(s, len, "include/generated/autoconf.h");
250}
251
252/* Do not parse these files */
253static int is_no_parse_file(const char *s, int len)
254{
255 /* rustc may list binary files in dep-info */
256 return str_ends_with(s, len, ".rlib") ||
257 str_ends_with(s, len, ".rmeta") ||
258 str_ends_with(s, len, ".so");
259}
260
261/*
262 * Important: The below generated source_foo.o and deps_foo.o variable
263 * assignments are parsed not only by make, but also by the rather simple
264 * parser in scripts/mod/sumversion.c.
265 */
266static void parse_dep_file(char *p, const char *target)
267{
268 bool saw_any_target = false;
269 bool is_target = true;
270 bool is_source = false;
271 bool need_parse;
272 char *q, saved_c;
273
274 while (*p) {
275 /* handle some special characters first. */
276 switch (*p) {
277 case '#':
278 /*
279 * skip comments.
280 * rustc may emit comments to dep-info.
281 */
282 p++;
283 while (*p != '\0' && *p != '\n') {
284 /*
285 * escaped newlines continue the comment across
286 * multiple lines.
287 */
288 if (*p == '\\')
289 p++;
290 p++;
291 }
292 continue;
293 case ' ':
294 case '\t':
295 /* skip whitespaces */
296 p++;
297 continue;
298 case '\\':
299 /*
300 * backslash/newline combinations continue the
301 * statement. Skip it just like a whitespace.
302 */
303 if (*(p + 1) == '\n') {
304 p += 2;
305 continue;
306 }
307 break;
308 case '\n':
309 /*
310 * Makefiles use a line-based syntax, where the newline
311 * is the end of a statement. After seeing a newline,
312 * we expect the next token is a target.
313 */
314 p++;
315 is_target = true;
316 continue;
317 case ':':
318 /*
319 * assume the first dependency after a colon as the
320 * source file.
321 */
322 p++;
323 is_target = false;
324 is_source = true;
325 continue;
326 }
327
328 /* find the end of the token */
329 q = p;
330 while (*q != ' ' && *q != '\t' && *q != '\n' && *q != '#' && *q != ':') {
331 if (*q == '\\') {
332 /*
333 * backslash/newline combinations work like as
334 * a whitespace, so this is the end of token.
335 */
336 if (*(q + 1) == '\n')
337 break;
338
339 /* escaped special characters */
340 if (*(q + 1) == '#' || *(q + 1) == ':') {
341 memmove(p + 1, p, q - p);
342 p++;
343 }
344
345 q++;
346 }
347
348 if (*q == '\0')
349 break;
350 q++;
351 }
352
353 /* Just discard the target */
354 if (is_target) {
355 p = q;
356 continue;
357 }
358
359 saved_c = *q;
360 *q = '\0';
361 need_parse = false;
362
363 /*
364 * Do not list the source file as dependency, so that kbuild is
365 * not confused if a .c file is rewritten into .S or vice versa.
366 * Storing it in source_* is needed for modpost to compute
367 * srcversions.
368 */
369 if (is_source) {
370 /*
371 * The DT build rule concatenates multiple dep files.
372 * When processing them, only process the first source
373 * name, which will be the original one, and ignore any
374 * other source names, which will be intermediate
375 * temporary files.
376 *
377 * rustc emits the same dependency list for each
378 * emission type. It is enough to list the source name
379 * just once.
380 */
381 if (!saw_any_target) {
382 saw_any_target = true;
383 printf("source_%s := %s\n\n", target, p);
384 printf("deps_%s := \\\n", target);
385 need_parse = true;
386 }
387 } else if (!is_ignored_file(p, q - p) &&
388 !in_hashtable(p, q - p, file_hashtab)) {
389 printf(" %s \\\n", p);
390 need_parse = true;
391 }
392
393 if (need_parse && !is_no_parse_file(p, q - p)) {
394 void *buf;
395
396 buf = read_file(p);
397 parse_config_file(buf);
398 free(buf);
399 }
400
401 is_source = false;
402 *q = saved_c;
403 p = q;
404 }
405
406 if (!saw_any_target) {
407 fprintf(stderr, "fixdep: parse error; no targets found\n");
408 exit(1);
409 }
410
411 printf("\n%s: $(deps_%s)\n\n", target, target);
412 printf("$(deps_%s):\n", target);
413}
414
415int main(int argc, char *argv[])
416{
417 const char *depfile, *target, *cmdline;
418 void *buf;
419
420 if (argc != 4)
421 usage();
422
423 depfile = argv[1];
424 target = argv[2];
425 cmdline = argv[3];
426
427 printf("savedcmd_%s := %s\n\n", target, cmdline);
428
429 buf = read_file(depfile);
430 parse_dep_file(buf, target);
431 free(buf);
432
433 fflush(stdout);
434
435 /*
436 * In the intended usage, the stdout is redirected to .*.cmd files.
437 * Call ferror() to catch errors such as "No space left on device".
438 */
439 if (ferror(stdout)) {
440 fprintf(stderr, "fixdep: not all data was written to the output\n");
441 exit(1);
442 }
443
444 return 0;
445}