scripts/split-include.c

   1 /*
   2  * split-include.c
   3  *
   4  * Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.
   5  * This is a C version of syncdep.pl by Werner Almesberger.
   6  *
   7  * This program takes autoconf.h as input and outputs a directory full
   8  * of one-line include files, merging onto the old values.
   9  *
  10  * Think of the configuration options as key-value pairs.  Then there
  11  * are five cases:
  12  *
  13  *    key      old value   new value   action
  14  *
  15  *    KEY-1    VALUE-1     VALUE-1     leave file alone
  16  *    KEY-2    VALUE-2A    VALUE-2B    write VALUE-2B into file
  17  *    KEY-3    -           VALUE-3     write VALUE-3  into file
  18  *    KEY-4    VALUE-4     -           write an empty file
  19  *    KEY-5    (empty)     -           leave old empty file alone
  20  */
  21
  22 #include <sys/stat.h>
  23 #include <sys/types.h>
  24
  25 #include <ctype.h>
  26 #include <errno.h>
  27 #include <fcntl.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32
  33 #define ERROR_EXIT(strExit)                                             \
  34     {                                                                   \
  35         const int errnoSave = errno;                                    \
  36         fprintf(stderr, "%s: ", str_my_name);                           \
  37         errno = errnoSave;                                              \
  38         perror((strExit));                                              \
  39         exit(1);                                                        \
  40     }
  41
  42
  43
  44 int main(int argc, const char * argv [])
  45 {
  46     const char * str_my_name;
  47     const char * str_file_autoconf;
  48     const char * str_dir_config;
  49
  50     FILE * fp_config;
  51     FILE * fp_target;
  52     FILE * fp_find;
  53
  54     int buffer_size;
  55
  56     char * line;
  57     char * old_line;
  58     char * list_target;
  59     char * ptarget;
  60
  61     struct stat stat_buf;
  62
  63     /* Check arg count. */
  64     if (argc != 3)
  65     {
  66         fprintf(stderr, "%s: wrong number of arguments.\n", argv[0]);
  67         exit(1);
  68     }
  69
  70     str_my_name       = argv[0];
  71     str_file_autoconf = argv[1];
  72     str_dir_config    = argv[2];
  73
  74     /* Find a buffer size. */
  75     if (stat(str_file_autoconf, &stat_buf) != 0)
  76         ERROR_EXIT(str_file_autoconf);
  77     buffer_size = 2 * stat_buf.st_size + 4096;
  78
  79     /* Allocate buffers. */
  80     if ( (line        = malloc(buffer_size)) == NULL
  81     ||   (old_line    = malloc(buffer_size)) == NULL
  82     ||   (list_target = malloc(buffer_size)) == NULL )
  83         ERROR_EXIT(str_file_autoconf);
  84
  85     /* Open autoconfig file. */
  86     if ((fp_config = fopen(str_file_autoconf, "r")) == NULL)
  87         ERROR_EXIT(str_file_autoconf);
  88
  89     /* Make output directory if needed. */
  90     if (stat(str_dir_config, &stat_buf) != 0)
  91     {
  92         if (mkdir(str_dir_config, 0755) != 0)
  93             ERROR_EXIT(str_dir_config);
  94     }
  95
  96     /* Change to output directory. */
  97     if (chdir(str_dir_config) != 0)
  98         ERROR_EXIT(str_dir_config);
  99
 100     /* Put initial separator into target list. */
 101     ptarget = list_target;
 102     *ptarget++ = '\n';
 103
 104     /* Read config lines. */
 105     while (fgets(line, buffer_size, fp_config))
 106     {
 107         const char * str_config;
 108         int is_same;
 109         int itarget;
 110
 111         if (line[0] != '#')
 112             continue;
 113         if ((str_config = strstr(line, "CONFIG_")) == NULL)
 114             continue;
 115
 116         /* Make the output file name. */
 117         str_config += sizeof("CONFIG_") - 1;
 118         for (itarget = 0; !isspace(str_config[itarget]); itarget++)
 119         {
 120             char c = str_config[itarget];
 121             if (isupper(c)) c = tolower(c);
 122             if (c == '_')   c = '/';
 123             ptarget[itarget] = c;
 124         }
 125         ptarget[itarget++] = '.';
 126         ptarget[itarget++] = 'h';
 127         ptarget[itarget++] = '\0';
 128
 129         /* Check for existing file. */
 130         is_same = 0;
 131         if ((fp_target = fopen(ptarget, "r")) != NULL)
 132         {
 133             fgets(old_line, buffer_size, fp_target);
 134             if (fclose(fp_target) != 0)
 135                 ERROR_EXIT(ptarget);
 136             if (!strcmp(line, old_line))
 137                 is_same = 1;
 138         }
 139
 140         if (!is_same)
 141         {
 142             /* Auto-create directories. */
 143             int islash;
 144             for (islash = 0; islash < itarget; islash++)
 145             {
 146                 if (ptarget[islash] == '/')
 147                 {
 148                     ptarget[islash] = '\0';
 149                     if (stat(ptarget, &stat_buf) != 0
 150                     &&  mkdir(ptarget, 0755)     != 0)
 151                         ERROR_EXIT( ptarget );
 152                     ptarget[islash] = '/';
 153                 }
 154             }
 155
 156             /* Write the file. */
 157             if ((fp_target = fopen(ptarget, "w" )) == NULL)
 158                 ERROR_EXIT(ptarget);
 159             fputs(line, fp_target);
 160             if (ferror(fp_target) || fclose(fp_target) != 0)
 161                 ERROR_EXIT(ptarget);
 162         }
 163
 164         /* Update target list */
 165         ptarget += itarget;
 166         *(ptarget-1) = '\n';
 167     }
 168
 169     /*
 170      * Close autoconfig file.
 171      * Terminate the target list.
 172      */
 173     if (fclose(fp_config) != 0)
 174         ERROR_EXIT(str_file_autoconf);
 175     *ptarget = '\0';
 176
 177     /*
 178      * Fix up existing files which have no new value.
 179      * This is Case 4 and Case 5.
 180      *
 181      * I re-read the tree and filter it against list_target.
 182      * This is crude.  But it avoids data copies.  Also, list_target
 183      * is compact and contiguous, so it easily fits into cache.
 184      *
 185      * Notice that list_target contains strings separated by \n,
 186      * with a \n before the first string and after the last.
 187      * fgets gives the incoming names a terminating \n.
 188      * So by having an initial \n, strstr will find exact matches.
 189      */
 190
 191     fp_find = popen("find * -type f -print", "r");
 192     if (fp_find == 0)
 193         ERROR_EXIT( "find" );
 194
 195     line[0] = '\n';
 196     while (fgets(line+1, buffer_size, fp_find))
 197     {
 198         if (strstr(list_target, line) == NULL)
 199         {
 200             /*
 201              * This is an old file with no CONFIG_* flag in autoconf.h.
 202              */
 203
 204             /* First strip the \n. */
 205             line[strlen(line)-1] = '\0';
 206
 207             /* Grab size. */
 208             if (stat(line+1, &stat_buf) != 0)
 209                 ERROR_EXIT(line);
 210
 211             /* If file is not empty, make it empty and give it a fresh date. */
 212             if (stat_buf.st_size != 0)
 213             {
 214                 if ((fp_target = fopen(line+1, "w")) == NULL)
 215                     ERROR_EXIT(line);
 216                 if (fclose(fp_target) != 0)
 217                     ERROR_EXIT(line);
 218             }
 219         }
 220     }
 221
 222     if (pclose(fp_find) != 0)
 223         ERROR_EXIT("find");
 224
 225     return 0;
 226 }