build system overhaul

scripts/basic/split-include.c

@@ -0,0 +1,226 @@
+/*
+ * 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)
+	    continue;
+
+	/* Make the output file name. */
+	str_config += sizeof("CONFIG_") - 1;
+	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)
+	{
+	    fgets(old_line, buffer_size, fp_target);
+	    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)
+		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;
+}