1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * "Optimize" a list of dependencies as spit out by gcc -MD
4 * for the build framework.
5 *
6 * Original author:
7 * Copyright 2002 by Kai Germaschewski <kai.germaschewski@gmx.de>
8 *
9 * This code has been borrowed from kbuild's fixdep (scripts/basic/fixdep.c),
10 * Please check it for detailed explanation. This fixdep borow only the
11 * base transformation of dependecies without the CONFIG mangle.
12 */
13
14 #include <sys/types.h>
15 #include <sys/stat.h>
16 #include <sys/mman.h>
17 #include <unistd.h>
18 #include <fcntl.h>
19 #include <string.h>
20 #include <stdlib.h>
21 #include <stdio.h>
22 #include <limits.h>
23
24 char *target;
25 char *depfile;
26 char *cmdline;
27
28 static void usage(void)
29 {
30 fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
31 exit(1);
32 }
33
34 /*
35 * Print out the commandline prefixed with cmd_<target filename> :=
36 */
37 static void print_cmdline(void)
38 {
39 printf("cmd_%s := %s\n\n", target, cmdline);
40 }
41
42 /*
43 * Important: The below generated source_foo.o and deps_foo.o variable
44 * assignments are parsed not only by make, but also by the rather simple
45 * parser in scripts/mod/sumversion.c.
46 */
47 static void parse_dep_file(void *map, size_t len)
48 {
49 char *m = map;
50 char *end = m + len;
51 char *p;
52 char s[PATH_MAX];
53 int is_target, has_target = 0;
54 int saw_any_target = 0;
55 int is_first_dep = 0;
56
57 while (m < end) {
58 /* Skip any "white space" */
59 while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
60 m++;
61 /* Find next "white space" */
62 p = m;
63 while (p < end && *p != ' ' && *p != '\\' && *p != '\n')
64 p++;
65 /* Is the token we found a target name? */
66 is_target = (*(p-1) == ':');
67 /* Don't write any target names into the dependency file */
68 if (is_target) {
69 /* The /next/ file is the first dependency */
70 is_first_dep = 1;
71 has_target = 1;
72 } else if (has_target) {
73 /* Save this token/filename */
74 memcpy(s, m, p-m);
75 s[p - m] = 0;
76
77 /*
78 * Do not list the source file as dependency,
79 * so that kbuild is not confused if a .c file
80 * is rewritten into .S or vice versa. Storing
81 * it in source_* is needed for modpost to
82 * compute srcversions.
83 */
84 if (is_first_dep) {
85 /*
86 * If processing the concatenation of
87 * multiple dependency files, only
88 * process the first target name, which
89 * will be the original source name,
90 * and ignore any other target names,
91 * which will be intermediate temporary
92 * files.
93 */
94 if (!saw_any_target) {
95 saw_any_target = 1;
96 printf("source_%s := %s\n\n",
97 target, s);
98 printf("deps_%s := \\\n",
99 target);
100 }
101 is_first_dep = 0;
102 } else
103 printf(" %s \\\n", s);
104 }
105 /*
106 * Start searching for next token immediately after the first
107 * "whitespace" character that follows this token.
108 */
109 m = p + 1;
110 }
111
112 if (!saw_any_target) {
113 fprintf(stderr, "fixdep: parse error; no targets found\n");
114 exit(1);
115 }
116
117 printf("\n%s: $(deps_%s)\n\n", target, target);
118 printf("$(deps_%s):\n", target);
119 }
120
121 static void print_deps(void)
122 {
123 struct stat st;
124 int fd;
125 void *map;
126
127 fd = open(depfile, O_RDONLY);
128 if (fd < 0) {
129 fprintf(stderr, "fixdep: error opening depfile: ");
130 perror(depfile);
131 exit(2);
132 }
133 if (fstat(fd, &st) < 0) {
134 fprintf(stderr, "fixdep: error fstat'ing depfile: ");
135 perror(depfile);
136 exit(2);
137 }
138 if (st.st_size == 0) {
139 fprintf(stderr, "fixdep: %s is empty\n", depfile);
140 close(fd);
141 return;
142 }
143 map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
144 if ((long) map == -1) {
145 perror("fixdep: mmap");
146 close(fd);
147 return;
148 }
149
150 parse_dep_file(map, st.st_size);
151
152 munmap(map, st.st_size);
153
154 close(fd);
155 }
156
157 int main(int argc, char **argv)
158 {
159 if (argc != 4)
160 usage();
161
162 depfile = argv[1];
163 target = argv[2];
164 cmdline = argv[3];
165
166 print_cmdline();
167 print_deps();
168
169 return 0;
170 }