tools/build/fixdep.c

   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
  23 char *target;
  24 char *depfile;
  25 char *cmdline;
  26
  27 static 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  */
  36 static 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  */
  46 static 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
 119 static 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
 155 int 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 }