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, has_target = 0;
  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                         has_target = 1;
  71                 } else if (has_target) {
  72                         /* Save this token/filename */
  73                         memcpy(s, m, p-m);
  74                         s[p - m] = 0;
  75
  76                         /*
  77                          * Do not list the source file as dependency,
  78                          * so that kbuild is not confused if a .c file
  79                          * is rewritten into .S or vice versa. Storing
  80                          * it in source_* is needed for modpost to
  81                          * compute srcversions.
  82                          */
  83                         if (is_first_dep) {
  84                                 /*
  85                                  * If processing the concatenation of
  86                                  * multiple dependency files, only
  87                                  * process the first target name, which
  88                                  * will be the original source name,
  89                                  * and ignore any other target names,
  90                                  * which will be intermediate temporary
  91                                  * files.
  92                                  */
  93                                 if (!saw_any_target) {
  94                                         saw_any_target = 1;
  95                                         printf("source_%s := %s\n\n",
  96                                                 target, s);
  97                                         printf("deps_%s := \\\n",
  98                                                 target);
  99                                 }
 100                                 is_first_dep = 0;
 101                         } else
 102                                 printf("  %s \\\n", s);
 103                 }
 104                 /*
 105                  * Start searching for next token immediately after the first
 106                  * "whitespace" character that follows this token.
 107                  */
 108                 m = p + 1;
 109         }
 110
 111         if (!saw_any_target) {
 112                 fprintf(stderr, "fixdep: parse error; no targets found\n");
 113                 exit(1);
 114         }
 115
 116         printf("\n%s: $(deps_%s)\n\n", target, target);
 117         printf("$(deps_%s):\n", target);
 118 }
 119
 120 static void print_deps(void)
 121 {
 122         struct stat st;
 123         int fd;
 124         void *map;
 125
 126         fd = open(depfile, O_RDONLY);
 127         if (fd < 0) {
 128                 fprintf(stderr, "fixdep: error opening depfile: ");
 129                 perror(depfile);
 130                 exit(2);
 131         }
 132         if (fstat(fd, &st) < 0) {
 133                 fprintf(stderr, "fixdep: error fstat'ing depfile: ");
 134                 perror(depfile);
 135                 exit(2);
 136         }
 137         if (st.st_size == 0) {
 138                 fprintf(stderr, "fixdep: %s is empty\n", depfile);
 139                 close(fd);
 140                 return;
 141         }
 142         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 143         if ((long) map == -1) {
 144                 perror("fixdep: mmap");
 145                 close(fd);
 146                 return;
 147         }
 148
 149         parse_dep_file(map, st.st_size);
 150
 151         munmap(map, st.st_size);
 152
 153         close(fd);
 154 }
 155
 156 int main(int argc, char **argv)
 157 {
 158         if (argc != 4)
 159                 usage();
 160
 161         depfile = argv[1];
 162         target  = argv[2];
 163         cmdline = argv[3];
 164
 165         print_cmdline();
 166         print_deps();
 167
 168         return 0;
 169 }