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 } 171