399 lines
9.6 KiB
C
399 lines
9.6 KiB
C
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/*
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* "Optimize" a list of dependencies as spit out by gcc -MD
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* for the kernel build
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* ===========================================================================
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*
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* Author Kai Germaschewski
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* Copyright 2002 by Kai Germaschewski <kai.germaschewski@gmx.de>
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*
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* This software may be used and distributed according to the terms
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* of the GNU General Public License, incorporated herein by reference.
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*
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*
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* Introduction:
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*
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* gcc produces a very nice and correct list of dependencies which
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* tells make when to remake a file.
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*
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* To use this list as-is however has the drawback that virtually
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* every file in the kernel includes <linux/autoconf.h>.
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*
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* If the user re-runs make *config, linux/autoconf.h will be
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* regenerated. make notices that and will rebuild every file which
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* includes autoconf.h, i.e. basically all files. This is extremely
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* annoying if the user just changed CONFIG_HIS_DRIVER from n to m.
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*
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* So we play the same trick that "mkdep" played before. We replace
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* the dependency on linux/autoconf.h by a dependency on every config
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* option which is mentioned in any of the listed prequisites.
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*
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* kconfig populates a tree in include/config/ with an empty file
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* for each config symbol and when the configuration is updated
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* the files representing changed config options are touched
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* which then let make pick up the changes and the files that use
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* the config symbols are rebuilt.
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*
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* So if the user changes his CONFIG_HIS_DRIVER option, only the objects
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* which depend on "include/linux/config/his/driver.h" will be rebuilt,
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* so most likely only his driver ;-)
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*
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* The idea above dates, by the way, back to Michael E Chastain, AFAIK.
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*
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* So to get dependencies right, there are two issues:
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* o if any of the files the compiler read changed, we need to rebuild
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* o if the command line given to the compile the file changed, we
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* better rebuild as well.
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*
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* The former is handled by using the -MD output, the later by saving
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* the command line used to compile the old object and comparing it
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* to the one we would now use.
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*
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* Again, also this idea is pretty old and has been discussed on
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* kbuild-devel a long time ago. I don't have a sensibly working
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* internet connection right now, so I rather don't mention names
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* without double checking.
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*
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* This code here has been based partially based on mkdep.c, which
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* says the following about its history:
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*
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* Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.
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* This is a C version of syncdep.pl by Werner Almesberger.
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*
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*
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* It is invoked as
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*
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* fixdep <depfile> <target> <cmdline>
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*
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* and will read the dependency file <depfile>
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*
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* The transformed dependency snipped is written to stdout.
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*
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* It first generates a line
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*
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* cmd_<target> = <cmdline>
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*
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* and then basically copies the .<target>.d file to stdout, in the
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* process filtering out the dependency on linux/autoconf.h and adding
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* dependencies on include/config/my/option.h for every
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* CONFIG_MY_OPTION encountered in any of the prequisites.
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*
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* It will also filter out all the dependencies on *.ver. We need
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* to make sure that the generated version checksum are globally up
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* to date before even starting the recursive build, so it's too late
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* at this point anyway.
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*
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* The algorithm to grep for "CONFIG_..." is bit unusual, but should
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* be fast ;-) We don't even try to really parse the header files, but
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* merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will
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* be picked up as well. It's not a problem with respect to
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* correctness, since that can only give too many dependencies, thus
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* we cannot miss a rebuild. Since people tend to not mention totally
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* unrelated CONFIG_ options all over the place, it's not an
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* efficiency problem either.
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*
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* (Note: it'd be easy to port over the complete mkdep state machine,
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* but I don't think the added complexity is worth it)
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*/
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/*
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* Note 2: if somebody writes HELLO_CONFIG_BOOM in a file, it will depend onto
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* CONFIG_BOOM. This could seem a bug (not too hard to fix), but please do not
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* fix it! Some UserModeLinux files (look at arch/um/) call CONFIG_BOOM as
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* UML_CONFIG_BOOM, to avoid conflicts with /usr/include/linux/autoconf.h,
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* through arch/um/include/uml-config.h; this fixdep "bug" makes sure that
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* those files will have correct dependencies.
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <limits.h>
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#include <ctype.h>
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#include <arpa/inet.h>
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#define INT_CONF ntohl(0x434f4e46)
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#define INT_ONFI ntohl(0x4f4e4649)
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#define INT_NFIG ntohl(0x4e464947)
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#define INT_FIG_ ntohl(0x4649475f)
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char *target;
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char *depfile;
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char *cmdline;
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static void usage(void)
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{
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fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
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exit(1);
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}
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/*
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* Print out the commandline prefixed with cmd_<target filename> :=
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*/
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static void print_cmdline(void)
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{
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printf("cmd_%s := %s\n\n", target, cmdline);
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}
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char * str_config = NULL;
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int size_config = 0;
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int len_config = 0;
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/*
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* Grow the configuration string to a desired length.
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* Usually the first growth is plenty.
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*/
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static void grow_config(int len)
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{
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while (len_config + len > size_config) {
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if (size_config == 0)
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size_config = 2048;
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str_config = realloc(str_config, size_config *= 2);
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if (str_config == NULL)
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{ perror("fixdep:malloc"); exit(1); }
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}
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}
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/*
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* Lookup a value in the configuration string.
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*/
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static int is_defined_config(const char * name, int len)
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{
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const char * pconfig;
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const char * plast = str_config + len_config - len;
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for ( pconfig = str_config + 1; pconfig < plast; pconfig++ ) {
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if (pconfig[ -1] == '\n'
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&& pconfig[len] == '\n'
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&& !memcmp(pconfig, name, len))
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return 1;
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}
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return 0;
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}
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/*
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* Add a new value to the configuration string.
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*/
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static void define_config(const char * name, int len)
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{
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grow_config(len + 1);
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memcpy(str_config+len_config, name, len);
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len_config += len;
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str_config[len_config++] = '\n';
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}
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/*
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* Clear the set of configuration strings.
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*/
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static void clear_config(void)
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{
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len_config = 0;
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define_config("", 0);
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}
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/*
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* Record the use of a CONFIG_* word.
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*/
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static void use_config(char *m, int slen)
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{
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char s[PATH_MAX];
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char *p;
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if (is_defined_config(m, slen))
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return;
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define_config(m, slen);
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memcpy(s, m, slen); s[slen] = 0;
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for (p = s; p < s + slen; p++) {
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if (*p == '_')
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*p = '/';
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else
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*p = tolower((int)*p);
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}
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printf(" $(wildcard include/config/%s.h) \\\n", s);
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}
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static void parse_config_file(char *map, size_t len)
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{
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int *end = (int *) (map + len);
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/* start at +1, so that p can never be < map */
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int *m = (int *) map + 1;
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char *p, *q;
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for (; m < end; m++) {
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if (*m == INT_CONF) { p = (char *) m ; goto conf; }
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if (*m == INT_ONFI) { p = (char *) m-1; goto conf; }
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if (*m == INT_NFIG) { p = (char *) m-2; goto conf; }
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if (*m == INT_FIG_) { p = (char *) m-3; goto conf; }
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continue;
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conf:
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if (p > map + len - 7)
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continue;
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if (memcmp(p, "CONFIG_", 7))
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continue;
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for (q = p + 7; q < map + len; q++) {
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if (!(isalnum(*q) || *q == '_'))
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goto found;
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}
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continue;
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found:
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if (!memcmp(q - 7, "_MODULE", 7))
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q -= 7;
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if( (q-p-7) < 0 )
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continue;
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use_config(p+7, q-p-7);
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}
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}
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/* test is s ends in sub */
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static int strrcmp(char *s, char *sub)
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{
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int slen = strlen(s);
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int sublen = strlen(sub);
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if (sublen > slen)
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return 1;
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return memcmp(s + slen - sublen, sub, sublen);
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}
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static void do_config_file(char *filename)
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{
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struct stat st;
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int fd;
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void *map;
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fd = open(filename, O_RDONLY);
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if (fd < 0) {
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fprintf(stderr, "fixdep: ");
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perror(filename);
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exit(2);
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}
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fstat(fd, &st);
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if (st.st_size == 0) {
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close(fd);
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return;
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}
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map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
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if ((long) map == -1) {
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perror("fixdep: mmap");
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close(fd);
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return;
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}
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parse_config_file(map, st.st_size);
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munmap(map, st.st_size);
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close(fd);
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}
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static void parse_dep_file(void *map, size_t len)
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{
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char *m = map;
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char *end = m + len;
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char *p;
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char s[PATH_MAX];
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p = strchr(m, ':');
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if (!p) {
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fprintf(stderr, "fixdep: parse error\n");
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exit(1);
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}
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memcpy(s, m, p-m); s[p-m] = 0;
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printf("deps_%s := \\\n", target);
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m = p+1;
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clear_config();
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while (m < end) {
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while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
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m++;
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p = m;
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while (p < end && *p != ' ') p++;
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if (p == end) {
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do p--; while (!isalnum(*p));
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p++;
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}
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memcpy(s, m, p-m); s[p-m] = 0;
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if (strrcmp(s, "include/linux/autoconf.h") &&
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strrcmp(s, "arch/um/include/uml-config.h") &&
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strrcmp(s, ".ver")) {
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printf(" %s \\\n", s);
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do_config_file(s);
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}
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m = p + 1;
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}
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printf("\n%s: $(deps_%s)\n\n", target, target);
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printf("$(deps_%s):\n", target);
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}
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static void print_deps(void)
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{
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struct stat st;
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int fd;
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void *map;
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fd = open(depfile, O_RDONLY);
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if (fd < 0) {
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fprintf(stderr, "fixdep: ");
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perror(depfile);
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exit(2);
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}
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fstat(fd, &st);
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if (st.st_size == 0) {
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fprintf(stderr,"fixdep: %s is empty\n",depfile);
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close(fd);
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return;
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}
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map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
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if ((long) map == -1) {
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perror("fixdep: mmap");
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close(fd);
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return;
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}
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parse_dep_file(map, st.st_size);
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munmap(map, st.st_size);
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close(fd);
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}
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static void traps(void)
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{
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static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";
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int *p = (int *)test;
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if (*p != INT_CONF) {
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fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",
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*p);
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exit(2);
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}
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}
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||
|
|
int main(int argc, char *argv[])
|
||
|
|
{
|
||
|
|
traps();
|
||
|
|
|
||
|
|
if (argc != 4)
|
||
|
|
usage();
|
||
|
|
|
||
|
|
depfile = argv[1];
|
||
|
|
target = argv[2];
|
||
|
|
cmdline = argv[3];
|
||
|
|
|
||
|
|
print_cmdline();
|
||
|
|
print_deps();
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|