1/*
  2 * "Optimize" a list of dependencies as spit out by gcc -MD
  3 * for the build framework.
  4 *
  5 * Original author:
  6 *   Copyright    2002 by Kai Germaschewski  <kai.germaschewski@gmx.de>
  7 *
  8 * This code has been borrowed from kbuild's fixdep (scripts/basic/fixdep.c),
  9 * Please check it for detailed explanation. This fixdep borow only the
 10 * base transformation of dependecies without the CONFIG mangle.
 11 */
 12
 13#include <sys/types.h>
 14#include <sys/stat.h>
 15#include <sys/mman.h>
 16#include <unistd.h>
 17#include <fcntl.h>
 18#include <string.h>
 19#include <stdlib.h>
 20#include <stdio.h>
 21#include <limits.h>
 22
 23char *target;
 24char *depfile;
 25char *cmdline;
 26
 27static void usage(void)
 28{
 29	fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
 30	exit(1);
 31}
 32
 33/*
 34 * Print out the commandline prefixed with cmd_<target filename> :=
 35 */
 36static void print_cmdline(void)
 37{
 38	printf("cmd_%s := %s\n\n", target, cmdline);
 39}
 40
 41/*
 42 * Important: The below generated source_foo.o and deps_foo.o variable
 43 * assignments are parsed not only by make, but also by the rather simple
 44 * parser in scripts/mod/sumversion.c.
 45 */
 46static void parse_dep_file(void *map, size_t len)
 47{
 48	char *m = map;
 49	char *end = m + len;
 50	char *p;
 51	char s[PATH_MAX];
 52	int is_target;
 53	int saw_any_target = 0;
 54	int is_first_dep = 0;
 55
 56	while (m < end) {
 57		/* Skip any "white space" */
 58		while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
 59			m++;
 60		/* Find next "white space" */
 61		p = m;
 62		while (p < end && *p != ' ' && *p != '\\' && *p != '\n')
 63			p++;
 64		/* Is the token we found a target name? */
 65		is_target = (*(p-1) == ':');
 66		/* Don't write any target names into the dependency file */
 67		if (is_target) {
 68			/* The /next/ file is the first dependency */
 69			is_first_dep = 1;
 70		} else {
 71			/* Save this token/filename */
 72			memcpy(s, m, p-m);
 73			s[p - m] = 0;
 74
 75			/*
 76			 * Do not list the source file as dependency,
 77			 * so that kbuild is not confused if a .c file
 78			 * is rewritten into .S or vice versa. Storing
 79			 * it in source_* is needed for modpost to
 80			 * compute srcversions.
 81			 */
 82			if (is_first_dep) {
 83				/*
 84				 * If processing the concatenation of
 85				 * multiple dependency files, only
 86				 * process the first target name, which
 87				 * will be the original source name,
 88				 * and ignore any other target names,
 89				 * which will be intermediate temporary
 90				 * files.
 91				 */
 92				if (!saw_any_target) {
 93					saw_any_target = 1;
 94					printf("source_%s := %s\n\n",
 95						target, s);
 96					printf("deps_%s := \\\n",
 97						target);
 98				}
 99				is_first_dep = 0;
100			} else
101				printf("  %s \\\n", s);
102		}
103		/*
104		 * Start searching for next token immediately after the first
105		 * "whitespace" character that follows this token.
106		 */
107		m = p + 1;
108	}
109
110	if (!saw_any_target) {
111		fprintf(stderr, "fixdep: parse error; no targets found\n");
112		exit(1);
113	}
114
115	printf("\n%s: $(deps_%s)\n\n", target, target);
116	printf("$(deps_%s):\n", target);
117}
118
119static void print_deps(void)
120{
121	struct stat st;
122	int fd;
123	void *map;
124
125	fd = open(depfile, O_RDONLY);
126	if (fd < 0) {
127		fprintf(stderr, "fixdep: error opening depfile: ");
128		perror(depfile);
129		exit(2);
130	}
131	if (fstat(fd, &st) < 0) {
132		fprintf(stderr, "fixdep: error fstat'ing depfile: ");
133		perror(depfile);
134		exit(2);
135	}
136	if (st.st_size == 0) {
137		fprintf(stderr, "fixdep: %s is empty\n", depfile);
138		close(fd);
139		return;
140	}
141	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
142	if ((long) map == -1) {
143		perror("fixdep: mmap");
144		close(fd);
145		return;
146	}
147
148	parse_dep_file(map, st.st_size);
149
150	munmap(map, st.st_size);
151
152	close(fd);
153}
154
155int main(int argc, char **argv)
156{
157	if (argc != 4)
158		usage();
159
160	depfile = argv[1];
161	target  = argv[2];
162	cmdline = argv[3];
163
164	print_cmdline();
165	print_deps();
166
167	return 0;
168}