2 * subst.c --- substitution program
4 * Subst is used as a quicky program to do @ substitutions
14 #include <sys/types.h>
30 struct subst_entry
*next
;
33 struct subst_entry
*subst_table
= 0;
35 static int add_subst(char *name
, char *value
)
37 struct subst_entry
*ent
= 0;
41 ent
= (struct subst_entry
*) malloc(sizeof(struct subst_entry
));
44 ent
->name
= (char *) malloc(strlen(name
)+1);
47 ent
->value
= (char *) malloc(strlen(value
)+1);
50 strcpy(ent
->name
, name
);
51 strcpy(ent
->value
, value
);
52 ent
->next
= subst_table
;
64 static struct subst_entry
*fetch_subst_entry(char *name
)
66 struct subst_entry
*ent
;
68 for (ent
= subst_table
; ent
; ent
= ent
->next
) {
69 if (strcmp(name
, ent
->name
) == 0)
76 * Given the starting and ending position of the replacement name,
77 * check to see if it is valid, and pull it out if it is.
79 static char *get_subst_symbol(const char *begin
, size_t len
, char prefix
)
81 static char replace_name
[128];
88 if (len
> sizeof(replace_name
)-2)
90 memcpy(start
, begin
, len
);
94 * The substitution variable must all be in the of [0-9A-Za-z_].
95 * If it isn't, this must be an invalid symbol name.
97 for (cp
= start
; *cp
; cp
++) {
98 if (!(*cp
>= 'a' && *cp
<= 'z') &&
99 !(*cp
>= 'A' && *cp
<= 'Z') &&
100 !(*cp
>= '0' && *cp
<= '9') &&
104 return (replace_name
);
107 static void replace_string(char *begin
, char *end
, char *newstr
)
109 int replace_len
, len
;
111 replace_len
= strlen(newstr
);
113 if (replace_len
== 0)
114 memmove(begin
, end
+1, strlen(end
)+1);
115 else if (replace_len
!= len
+1)
116 memmove(end
+(replace_len
-len
-1), end
,
118 memcpy(begin
, newstr
, replace_len
);
121 static void substitute_line(char *line
)
123 char *ptr
, *name_ptr
, *end_ptr
;
124 struct subst_entry
*ent
;
129 * Expand all @FOO@ substitutions
133 name_ptr
= strchr(ptr
, '@');
136 if (*(++name_ptr
) == '@') {
138 * Handle tytso@@mit.edu --> tytso@mit.edu
140 memmove(name_ptr
-1, name_ptr
, strlen(name_ptr
)+1);
144 end_ptr
= strchr(name_ptr
, '@');
147 len
= end_ptr
- name_ptr
;
148 replace_name
= get_subst_symbol(name_ptr
, len
, 0);
153 ent
= fetch_subst_entry(replace_name
);
155 fprintf(stderr
, "Unfound expansion: '%s'\n",
161 fprintf(stderr
, "Replace name = '%s' with '%s'\n",
162 replace_name
, ent
->value
);
165 replace_string(ptr
, end_ptr
, ent
->value
);
166 if ((ent
->value
[0] == '@') &&
167 (strlen(replace_name
) == strlen(ent
->value
)-2) &&
168 !strncmp(replace_name
, ent
->value
+1,
169 strlen(ent
->value
)-2))
170 /* avoid an infinite loop */
171 ptr
+= strlen(ent
->value
);
174 * Now do a second pass to expand ${FOO}
178 name_ptr
= strchr(ptr
, '$');
181 if (*(++name_ptr
) != '{') {
186 end_ptr
= strchr(name_ptr
, '}');
189 len
= end_ptr
- name_ptr
;
190 replace_name
= get_subst_symbol(name_ptr
, len
, '$');
195 ent
= fetch_subst_entry(replace_name
);
201 fprintf(stderr
, "Replace name = '%s' with '%s'\n",
202 replace_name
, ent
->value
);
205 replace_string(ptr
, end_ptr
, ent
->value
);
209 static void parse_config_file(FILE *f
)
215 memset(line
, 0, sizeof(line
));
216 if (fgets(line
, sizeof(line
), f
) == NULL
)
219 * Strip newlines and comments.
221 cp
= strchr(line
, '\n');
224 cp
= strchr(line
, '#');
228 * Skip trailing and leading whitespace
230 for (cp
= line
+ strlen(line
) - 1; cp
>= line
; cp
--) {
231 if (*cp
== ' ' || *cp
== '\t')
237 while (*cp
&& isspace(*cp
))
246 * Ignore future extensions
251 * Parse substitutions
253 for (cp
= ptr
; *cp
; cp
++)
257 for (cp
++; *cp
; cp
++)
261 printf("Substitute: '%s' for '%s'\n", ptr
, cp
? cp
: "<NULL>");
268 * Return 0 if the files are different, 1 if the files are the same.
270 static int compare_file(const char *outfn
, const char *newfn
)
273 char oldbuf
[2048], newbuf
[2048], *oldcp
, *newcp
;
276 old_f
= fopen(outfn
, "r");
279 new_f
= fopen(newfn
, "r");
286 oldcp
= fgets(oldbuf
, sizeof(oldbuf
), old_f
);
287 newcp
= fgets(newbuf
, sizeof(newbuf
), new_f
);
288 if (!oldcp
&& !newcp
) {
292 if (!oldcp
|| !newcp
|| strcmp(oldbuf
, newbuf
)) {
304 int main(int argc
, char **argv
)
309 char *outfn
= NULL
, *newfn
= NULL
;
311 int adjust_timestamp
= 0;
315 while ((c
= getopt (argc
, argv
, "f:tv")) != EOF
) {
318 in
= fopen(optarg
, "r");
323 parse_config_file(in
);
333 fprintf(stderr
, "%s: [-f config-file] [file]\n",
339 in
= fopen(argv
[optind
], "r");
341 perror(argv
[optind
]);
349 outfn
= argv
[optind
];
350 newfn
= (char *) malloc(strlen(outfn
)+20);
352 fprintf(stderr
, "Memory error! Exiting.\n");
355 strcpy(newfn
, outfn
);
356 strcat(newfn
, ".new");
357 out
= fopen(newfn
, "w");
368 if (fgets(line
, sizeof(line
), in
) == NULL
)
370 substitute_line(line
);
377 if (compare_file(outfn
, newfn
)) {
379 printf("No change, keeping %s.\n", outfn
);
380 if (adjust_timestamp
) {
381 if (stat(outfn
, &stbuf
) == 0) {
383 printf("Updating modtime for %s\n", outfn
);
384 ut
.actime
= stbuf
.st_atime
;
385 ut
.modtime
= time(0);
386 if (utime(outfn
, &ut
) < 0)
393 printf("Creating or replacing %s.\n", outfn
);
394 rename(newfn
, outfn
);
396 /* set read-only to alert user it is a generated file */
397 if (stat(outfn
, &st
) == 0)
398 chmod(outfn
, st
.st_mode
& ~0222);