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	/* Make the output file name. */
117	str_config += sizeof("CONFIG_") - 1;
118	for (itarget = 0; !isspace(str_config[itarget]); itarget++)
119	{
120	    int c = (unsigned char) 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 -name \"*.h\" -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}
227