linuxdebug/tools/build/fixdep.c

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2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0
/*
* "Optimize" a list of dependencies as spit out by gcc -MD
* for the build framework.
*
* Original author:
* Copyright 2002 by Kai Germaschewski <kai.germaschewski@gmx.de>
*
* This code has been borrowed from kbuild's fixdep (scripts/basic/fixdep.c),
* Please check it for detailed explanation. This fixdep borow only the
* base transformation of dependecies without the CONFIG mangle.
*/
#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>
char *target;
char *depfile;
char *cmdline;
static void usage(void)
{
fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
exit(1);
}
/*
* Print out the commandline prefixed with cmd_<target filename> :=
*/
static void print_cmdline(void)
{
printf("cmd_%s := %s\n\n", target, cmdline);
}
/*
* Important: The below generated source_foo.o and deps_foo.o variable
* assignments are parsed not only by make, but also by the rather simple
* parser in scripts/mod/sumversion.c.
*/
static void parse_dep_file(void *map, size_t len)
{
char *m = map;
char *end = m + len;
char *p;
char s[PATH_MAX];
int is_target, has_target = 0;
int saw_any_target = 0;
int is_first_dep = 0;
while (m < end) {
/* Skip any "white space" */
while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
m++;
/* Find next "white space" */
p = m;
while (p < end && *p != ' ' && *p != '\\' && *p != '\n')
p++;
/* Is the token we found a target name? */
is_target = (*(p-1) == ':');
/* Don't write any target names into the dependency file */
if (is_target) {
/* The /next/ file is the first dependency */
is_first_dep = 1;
has_target = 1;
} else if (has_target) {
/* Save this token/filename */
memcpy(s, m, p-m);
s[p - m] = 0;
/*
* Do not list the source file as dependency,
* so that kbuild is not confused if a .c file
* is rewritten into .S or vice versa. Storing
* it in source_* is needed for modpost to
* compute srcversions.
*/
if (is_first_dep) {
/*
* If processing the concatenation of
* multiple dependency files, only
* process the first target name, which
* will be the original source name,
* and ignore any other target names,
* which will be intermediate temporary
* files.
*/
if (!saw_any_target) {
saw_any_target = 1;
printf("source_%s := %s\n\n",
target, s);
printf("deps_%s := \\\n",
target);
}
is_first_dep = 0;
} else
printf(" %s \\\n", s);
}
/*
* Start searching for next token immediately after the first
* "whitespace" character that follows this token.
*/
m = p + 1;
}
if (!saw_any_target) {
fprintf(stderr, "fixdep: parse error; no targets found\n");
exit(1);
}
printf("\n%s: $(deps_%s)\n\n", target, target);
printf("$(deps_%s):\n", target);
}
static void print_deps(void)
{
struct stat st;
int fd;
void *map;
fd = open(depfile, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "fixdep: error opening depfile: ");
perror(depfile);
exit(2);
}
if (fstat(fd, &st) < 0) {
fprintf(stderr, "fixdep: error fstat'ing depfile: ");
perror(depfile);
exit(2);
}
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);
}
int main(int argc, char **argv)
{
if (argc != 4)
usage();
depfile = argv[1];
target = argv[2];
cmdline = argv[3];
print_cmdline();
print_deps();
return 0;
}