Subversion Repositories test_project

/*

 * "Optimize" a list of dependencies as spit out by gcc -MD

 * for the kernel build

 * ===========================================================================

 *

 * Author       Kai Germaschewski

 * Copyright    2002 by Kai Germaschewski  <kai.germaschewski@gmx.de>

 *

 * This software may be used and distributed according to the terms

 * of the GNU General Public License, incorporated herein by reference.

 *

 *

 * Introduction:

 *

 * gcc produces a very nice and correct list of dependencies which

 * tells make when to remake a file.

 *

 * To use this list as-is however has the drawback that virtually

 * every file in the kernel includes <linux/config.h> which then again

 * includes <linux/autoconf.h>

 *

 * If the user re-runs make *config, linux/autoconf.h will be

 * regenerated.  make notices that and will rebuild every file which

 * includes autoconf.h, i.e. basically all files. This is extremely

 * annoying if the user just changed CONFIG_HIS_DRIVER from n to m.

 *

 * So we play the same trick that "mkdep" played before. We replace

 * the dependency on linux/autoconf.h by a dependency on every config

 * option which is mentioned in any of the listed prequisites.

 *

 * kconfig populates a tree in include/config/ with an empty file

 * for each config symbol and when the configuration is updated

 * the files representing changed config options are touched

 * which then let make pick up the changes and the files that use

 * the config symbols are rebuilt.

 *

 * So if the user changes his CONFIG_HIS_DRIVER option, only the objects

 * which depend on "include/linux/config/his/driver.h" will be rebuilt,

 * so most likely only his driver ;-)

 *

 * The idea above dates, by the way, back to Michael E Chastain, AFAIK.

 *

 * So to get dependencies right, there are two issues:

 * o if any of the files the compiler read changed, we need to rebuild

 * o if the command line given to the compile the file changed, we

 *   better rebuild as well.

 *

 * The former is handled by using the -MD output, the later by saving

 * the command line used to compile the old object and comparing it

 * to the one we would now use.

 *

 * Again, also this idea is pretty old and has been discussed on

 * kbuild-devel a long time ago. I don't have a sensibly working

 * internet connection right now, so I rather don't mention names

 * without double checking.

 *

 * This code here has been based partially based on mkdep.c, which

 * says the following about its history:

 *

 *   Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.

 *   This is a C version of syncdep.pl by Werner Almesberger.

 *

 *

 * It is invoked as

 *

 *   fixdep <depfile> <target> <cmdline>

 *

 * and will read the dependency file <depfile>

 *

 * The transformed dependency snipped is written to stdout.

 *

 * It first generates a line

 *

 *   cmd_<target> = <cmdline>

 *

 * and then basically copies the .<target>.d file to stdout, in the

 * process filtering out the dependency on linux/autoconf.h and adding

 * dependencies on include/config/my/option.h for every

 * CONFIG_MY_OPTION encountered in any of the prequisites.

 *

 * It will also filter out all the dependencies on *.ver. We need

 * to make sure that the generated version checksum are globally up

 * to date before even starting the recursive build, so it's too late

 * at this point anyway.

 *

 * The algorithm to grep for "CONFIG_..." is bit unusual, but should

 * be fast ;-) We don't even try to really parse the header files, but

 * merely grep, i.e. if CONFIG_FOO is mentioned in a comment, it will

 * be picked up as well. It's not a problem with respect to

 * correctness, since that can only give too many dependencies, thus

 * we cannot miss a rebuild. Since people tend to not mention totally

 * unrelated CONFIG_ options all over the place, it's not an

 * efficiency problem either.

 *

 * (Note: it'd be easy to port over the complete mkdep state machine,

 *  but I don't think the added complexity is worth it)

 */

/*

 * Note 2: if somebody writes HELLO_CONFIG_BOOM in a file, it will depend onto

 * CONFIG_BOOM. This could seem a bug (not too hard to fix), but please do not

 * fix it! Some UserModeLinux files (look at arch/um/) call CONFIG_BOOM as

 * UML_CONFIG_BOOM, to avoid conflicts with /usr/include/linux/autoconf.h,

 * through arch/um/include/uml-config.h; this fixdep "bug" makes sure that

 * those files will have correct dependencies.

 */

#include <sys/types.h>

#include <sys/stat.h>

#include <sys/mman.h>

#include <unistd.h>

#include <fcntl.h>

#include <string.h>

#include <stdlib.h>

#include <stdio.h>

#include <limits.h>

#include <ctype.h>

#include <arpa/inet.h>

#define INT_CONF ntohl(0x434f4e46)

#define INT_ONFI ntohl(0x4f4e4649)

#define INT_NFIG ntohl(0x4e464947)

#define INT_FIG_ ntohl(0x4649475f)

char *target;

char *depfile;

char *cmdline;

void usage(void)

{

        fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");

        exit(1);

}

/*

 * Print out the commandline prefixed with cmd_<target filename> :=

 */

void print_cmdline(void)

{

        printf("cmd_%s := %s\n\n", target, cmdline);

}

char * str_config  = NULL;

int    size_config = 0;

int    len_config  = 0;

/*

 * Grow the configuration string to a desired length.

 * Usually the first growth is plenty.

 */

void grow_config(int len)

{

        while (len_config + len > size_config) {

                if (size_config == 0)

                        size_config = 2048;

                str_config = realloc(str_config, size_config *= 2);

                if (str_config == NULL)

                        { perror("fixdep:malloc"); exit(1); }

        }

}

/*

 * Lookup a value in the configuration string.

 */

int is_defined_config(const char * name, int len)

{

        const char * pconfig;

        const char * plast = str_config + len_config - len;

        for ( pconfig = str_config + 1; pconfig < plast; pconfig++ ) {

                if (pconfig[ -1] == '\n'

                &&  pconfig[len] == '\n'

                &&  !memcmp(pconfig, name, len))

                        return 1;

        }

        return 0;

}

/*

 * Add a new value to the configuration string.

 */

void define_config(const char * name, int len)

{

        grow_config(len + 1);

        memcpy(str_config+len_config, name, len);

        len_config += len;

        str_config[len_config++] = '\n';

}

/*

 * Clear the set of configuration strings.

 */

void clear_config(void)

{

        len_config = 0;

        define_config("", 0);

}

/*

 * Record the use of a CONFIG_* word.

 */

void use_config(char *m, int slen)

{

        char s[PATH_MAX];

        char *p;

        if (is_defined_config(m, slen))

            return;

        define_config(m, slen);

        memcpy(s, m, slen); s[slen] = 0;

        for (p = s; p < s + slen; p++) {

                if (*p == '_')

                        *p = '/';

                else

                        *p = tolower((int)*p);

        }

        printf("    $(wildcard include/config/%s.h) \\\n", s);

}

void parse_config_file(char *map, size_t len)

{

        int *end = (int *) (map + len);

        /* start at +1, so that p can never be < map */

        int *m   = (int *) map + 1;

        char *p, *q;

        for (; m < end; m++) {

                if (*m == INT_CONF) { p = (char *) m  ; goto conf; }

                if (*m == INT_ONFI) { p = (char *) m-1; goto conf; }

                if (*m == INT_NFIG) { p = (char *) m-2; goto conf; }

                if (*m == INT_FIG_) { p = (char *) m-3; goto conf; }

                continue;

        conf:

                if (p > map + len - 7)

                        continue;

                if (memcmp(p, "CONFIG_", 7))

                        continue;

                for (q = p + 7; q < map + len; q++) {

                        if (!(isalnum(*q) || *q == '_'))

                                goto found;

                }

                continue;

        found:

                if (!memcmp(q - 7, "_MODULE", 7))

                        q -= 7;

                if( (q-p-7) < 0 )

                        continue;

                use_config(p+7, q-p-7);

        }

}

/* test is s ends in sub */

int strrcmp(char *s, char *sub)

{

        int slen = strlen(s);

        int sublen = strlen(sub);

        if (sublen > slen)

                return 1;

        return memcmp(s + slen - sublen, sub, sublen);

}

void do_config_file(char *filename)

{

        struct stat st;

        int fd;

        void *map;

        fd = open(filename, O_RDONLY);

        if (fd < 0) {

                fprintf(stderr, "fixdep: ");

                perror(filename);

                exit(2);

        }

        fstat(fd, &st);

        if (st.st_size == 0) {

                close(fd);

                return;

        }

        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);

        if ((long) map == -1) {

                perror("fixdep: mmap");

                close(fd);

                return;

        }

        parse_config_file(map, st.st_size);

        munmap(map, st.st_size);

        close(fd);

}

void parse_dep_file(void *map, size_t len)

{

        char *m = map;

        char *end = m + len;

        char *p;

        char s[PATH_MAX];

        p = strchr(m, ':');

        if (!p) {

                fprintf(stderr, "fixdep: parse error\n");

                exit(1);

        }

        memcpy(s, m, p-m); s[p-m] = 0;

        printf("deps_%s := \\\n", target);

        m = p+1;

        clear_config();

        while (m < end) {

                while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))

                        m++;

                p = m;

                while (p < end && *p != ' ') p++;

                if (p == end) {

                        do p--; while (!isalnum(*p));

                        p++;

                }

                memcpy(s, m, p-m); s[p-m] = 0;

                if (strrcmp(s, "include/linux/autoconf.h") &&

                    strrcmp(s, "arch/um/include/uml-config.h") &&

                    strrcmp(s, ".ver")) {

                        printf("  %s \\\n", s);

                        do_config_file(s);

                }

                m = p + 1;

        }

        printf("\n%s: $(deps_%s)\n\n", target, target);

        printf("$(deps_%s):\n", target);

}

void print_deps(void)

{

        struct stat st;

        int fd;

        void *map;

        fd = open(depfile, O_RDONLY);

        if (fd < 0) {

                fprintf(stderr, "fixdep: ");

                perror(depfile);

                exit(2);

        }

        fstat(fd, &st);

        if (st.st_size == 0) {

                fprintf(stderr,"fixdep: %s is empty\n",depfile);

                close(fd);

                return;

        }

        map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);

        if ((long) map == -1) {

                perror("fixdep: mmap");

                close(fd);

                return;

        }

        parse_dep_file(map, st.st_size);

        munmap(map, st.st_size);

        close(fd);

}

void traps(void)

{

        static char test[] __attribute__((aligned(sizeof(int)))) = "CONF";

        if (*(int *)test != INT_CONF) {

                fprintf(stderr, "fixdep: sizeof(int) != 4 or wrong endianess? %#x\n",

                        *(int *)test);

                exit(2);

        }

}

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;

}