busybox/scripts/basic/split-include.c

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2006-10-05 15:47:08 +05:30
/*
* split-include.c
*
* Copyright abandoned, Michael Chastain, <mailto:mec@shout.net>.
* This is a C version of syncdep.pl by Werner Almesberger.
*
* This program takes autoconf.h as input and outputs a directory full
* of one-line include files, merging onto the old values.
*
* Think of the configuration options as key-value pairs. Then there
* are five cases:
*
* key old value new value action
*
* KEY-1 VALUE-1 VALUE-1 leave file alone
* KEY-2 VALUE-2A VALUE-2B write VALUE-2B into file
* KEY-3 - VALUE-3 write VALUE-3 into file
* KEY-4 VALUE-4 - write an empty file
* KEY-5 (empty) - leave old empty file alone
*/
#include <sys/stat.h>
#include <sys/types.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define ERROR_EXIT(strExit) \
{ \
const int errnoSave = errno; \
fprintf(stderr, "%s: ", str_my_name); \
errno = errnoSave; \
perror((strExit)); \
exit(1); \
}
int main(int argc, const char * argv [])
{
const char * str_my_name;
const char * str_file_autoconf;
const char * str_dir_config;
FILE * fp_config;
FILE * fp_target;
FILE * fp_find;
int buffer_size;
char * line;
char * old_line;
char * list_target;
char * ptarget;
struct stat stat_buf;
/* Check arg count. */
if (argc != 3)
{
fprintf(stderr, "%s: wrong number of arguments.\n", argv[0]);
exit(1);
}
str_my_name = argv[0];
str_file_autoconf = argv[1];
str_dir_config = argv[2];
/* Find a buffer size. */
if (stat(str_file_autoconf, &stat_buf) != 0)
ERROR_EXIT(str_file_autoconf);
buffer_size = 2 * stat_buf.st_size + 4096;
/* Allocate buffers. */
if ( (line = malloc(buffer_size)) == NULL
|| (old_line = malloc(buffer_size)) == NULL
|| (list_target = malloc(buffer_size)) == NULL )
ERROR_EXIT(str_file_autoconf);
/* Open autoconfig file. */
if ((fp_config = fopen(str_file_autoconf, "r")) == NULL)
ERROR_EXIT(str_file_autoconf);
/* Make output directory if needed. */
if (stat(str_dir_config, &stat_buf) != 0)
{
if (mkdir(str_dir_config, 0755) != 0)
ERROR_EXIT(str_dir_config);
}
/* Change to output directory. */
if (chdir(str_dir_config) != 0)
ERROR_EXIT(str_dir_config);
/* Put initial separator into target list. */
ptarget = list_target;
*ptarget++ = '\n';
/* Read config lines. */
while (fgets(line, buffer_size, fp_config))
{
const char * str_config;
int is_same;
int itarget;
if (line[0] != '#')
continue;
if ((str_config = strstr(line, " CONFIG_")) == NULL)
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continue;
/* We found #define CONFIG_foo or #undef CONFIG_foo.
* Make the output file name. */
str_config += sizeof(" CONFIG_") - 1;
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for (itarget = 0; !isspace(str_config[itarget]); itarget++)
{
int c = (unsigned char) str_config[itarget];
if (isupper(c)) c = tolower(c);
if (c == '_') c = '/';
ptarget[itarget] = c;
}
ptarget[itarget++] = '.';
ptarget[itarget++] = 'h';
ptarget[itarget++] = '\0';
/* Check for existing file. */
is_same = 0;
if ((fp_target = fopen(ptarget, "r")) != NULL)
{
if (!fgets(old_line, buffer_size, fp_target))
ERROR_EXIT(ptarget);
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if (fclose(fp_target) != 0)
ERROR_EXIT(ptarget);
if (!strcmp(line, old_line))
is_same = 1;
}
if (!is_same)
{
/* Auto-create directories. */
int islash;
for (islash = 0; islash < itarget; islash++)
{
if (ptarget[islash] == '/')
{
ptarget[islash] = '\0';
if (stat(ptarget, &stat_buf) != 0
&& mkdir(ptarget, 0755) != 0)
ERROR_EXIT( ptarget );
ptarget[islash] = '/';
}
}
/* Write the file. */
if ((fp_target = fopen(ptarget, "w")) == NULL)
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ERROR_EXIT(ptarget);
fputs(line, fp_target);
if (ferror(fp_target) || fclose(fp_target) != 0)
ERROR_EXIT(ptarget);
}
/* Update target list */
ptarget += itarget;
*(ptarget-1) = '\n';
}
/*
* Close autoconfig file.
* Terminate the target list.
*/
if (fclose(fp_config) != 0)
ERROR_EXIT(str_file_autoconf);
*ptarget = '\0';
/*
* Fix up existing files which have no new value.
* This is Case 4 and Case 5.
*
* I re-read the tree and filter it against list_target.
* This is crude. But it avoids data copies. Also, list_target
* is compact and contiguous, so it easily fits into cache.
*
* Notice that list_target contains strings separated by \n,
* with a \n before the first string and after the last.
* fgets gives the incoming names a terminating \n.
* So by having an initial \n, strstr will find exact matches.
*/
fp_find = popen("find * -type f -name \"*.h\" -print", "r");
if (fp_find == 0)
ERROR_EXIT( "find" );
line[0] = '\n';
while (fgets(line+1, buffer_size, fp_find))
{
if (strstr(list_target, line) == NULL)
{
/*
* This is an old file with no CONFIG_* flag in autoconf.h.
*/
/* First strip the \n. */
line[strlen(line)-1] = '\0';
/* Grab size. */
if (stat(line+1, &stat_buf) != 0)
ERROR_EXIT(line);
/* If file is not empty, make it empty and give it a fresh date. */
if (stat_buf.st_size != 0)
{
if ((fp_target = fopen(line+1, "w")) == NULL)
ERROR_EXIT(line);
if (fclose(fp_target) != 0)
ERROR_EXIT(line);
}
}
}
if (pclose(fp_find) != 0)
ERROR_EXIT("find");
return 0;
}