busybox/scripts/basic/split-include.c
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   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
  44int 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        /* We found #define CONFIG_foo or #undef CONFIG_foo.
 117         * Make the output file name. */
 118        str_config += sizeof(" CONFIG_") - 1;
 119        for (itarget = 0; !isspace(str_config[itarget]); itarget++)
 120        {
 121            int c = (unsigned char) str_config[itarget];
 122            if (isupper(c)) c = tolower(c);
 123            if (c == '_')   c = '/';
 124            ptarget[itarget] = c;
 125        }
 126        ptarget[itarget++] = '.';
 127        ptarget[itarget++] = 'h';
 128        ptarget[itarget++] = '\0';
 129
 130        /* Check for existing file. */
 131        is_same = 0;
 132        if ((fp_target = fopen(ptarget, "r")) != NULL)
 133        {
 134            if (!fgets(old_line, buffer_size, fp_target))
 135                ERROR_EXIT(ptarget);
 136            if (fclose(fp_target) != 0)
 137                ERROR_EXIT(ptarget);
 138            if (!strcmp(line, old_line))
 139                is_same = 1;
 140        }
 141
 142        if (!is_same)
 143        {
 144            /* Auto-create directories. */
 145            int islash;
 146            for (islash = 0; islash < itarget; islash++)
 147            {
 148                if (ptarget[islash] == '/')
 149                {
 150                    ptarget[islash] = '\0';
 151                    if (stat(ptarget, &stat_buf) != 0
 152                    &&  mkdir(ptarget, 0755)     != 0)
 153                        ERROR_EXIT( ptarget );
 154                    ptarget[islash] = '/';
 155                }
 156            }
 157
 158            /* Write the file. */
 159            if ((fp_target = fopen(ptarget,  "w")) == NULL)
 160                ERROR_EXIT(ptarget);
 161            fputs(line, fp_target);
 162            if (ferror(fp_target) || fclose(fp_target) != 0)
 163                ERROR_EXIT(ptarget);
 164        }
 165
 166        /* Update target list */
 167        ptarget += itarget;
 168        *(ptarget-1) = '\n';
 169    }
 170
 171    /*
 172     * Close autoconfig file.
 173     * Terminate the target list.
 174     */
 175    if (fclose(fp_config) != 0)
 176        ERROR_EXIT(str_file_autoconf);
 177    *ptarget = '\0';
 178
 179    /*
 180     * Fix up existing files which have no new value.
 181     * This is Case 4 and Case 5.
 182     *
 183     * I re-read the tree and filter it against list_target.
 184     * This is crude.  But it avoids data copies.  Also, list_target
 185     * is compact and contiguous, so it easily fits into cache.
 186     *
 187     * Notice that list_target contains strings separated by \n,
 188     * with a \n before the first string and after the last.
 189     * fgets gives the incoming names a terminating \n.
 190     * So by having an initial \n, strstr will find exact matches.
 191     */
 192
 193    fp_find = popen("find * -type f -name \"*.h\" -print", "r");
 194    if (fp_find == 0)
 195        ERROR_EXIT( "find" );
 196
 197    line[0] = '\n';
 198    while (fgets(line+1, buffer_size, fp_find))
 199    {
 200        if (strstr(list_target, line) == NULL)
 201        {
 202            /*
 203             * This is an old file with no CONFIG_* flag in autoconf.h.
 204             */
 205
 206            /* First strip the \n. */
 207            line[strlen(line)-1] = '\0';
 208
 209            /* Grab size. */
 210            if (stat(line+1, &stat_buf) != 0)
 211                ERROR_EXIT(line);
 212
 213            /* If file is not empty, make it empty and give it a fresh date. */
 214            if (stat_buf.st_size != 0)
 215            {
 216                if ((fp_target = fopen(line+1, "w")) == NULL)
 217                    ERROR_EXIT(line);
 218                if (fclose(fp_target) != 0)
 219                    ERROR_EXIT(line);
 220            }
 221        }
 222    }
 223
 224    if (pclose(fp_find) != 0)
 225        ERROR_EXIT("find");
 226
 227    return 0;
 228}
 229