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git.ipfire.org Git - thirdparty/e2fsprogs.git/blob - util/subst.c
2 * subst.c --- substitution program
4 * Subst is used as a quicky program to do @ substitutions
17 #include <sys/types.h>
22 #ifdef HAVE_SYS_TIME_H
37 struct subst_entry
*next
;
40 static struct subst_entry
*subst_table
= 0;
42 static int add_subst(char *name
, char *value
)
44 struct subst_entry
*ent
= 0;
46 ent
= (struct subst_entry
*) malloc(sizeof(struct subst_entry
));
49 ent
->name
= (char *) malloc(strlen(name
)+1);
52 ent
->value
= (char *) malloc(strlen(value
)+1);
55 strcpy(ent
->name
, name
);
56 strcpy(ent
->value
, value
);
57 ent
->next
= subst_table
;
68 static struct subst_entry
*fetch_subst_entry(char *name
)
70 struct subst_entry
*ent
;
72 for (ent
= subst_table
; ent
; ent
= ent
->next
) {
73 if (strcmp(name
, ent
->name
) == 0)
80 * Given the starting and ending position of the replacement name,
81 * check to see if it is valid, and pull it out if it is.
83 static char *get_subst_symbol(const char *begin
, size_t len
, char prefix
)
85 static char replace_name
[128];
92 if (len
> sizeof(replace_name
)-2)
94 memcpy(start
, begin
, len
);
98 * The substitution variable must all be in the of [0-9A-Za-z_].
99 * If it isn't, this must be an invalid symbol name.
101 for (cp
= start
; *cp
; cp
++) {
102 if (!(*cp
>= 'a' && *cp
<= 'z') &&
103 !(*cp
>= 'A' && *cp
<= 'Z') &&
104 !(*cp
>= '0' && *cp
<= '9') &&
108 return (replace_name
);
111 static void replace_string(char *begin
, char *end
, char *newstr
)
113 int replace_len
, len
;
115 replace_len
= strlen(newstr
);
117 if (replace_len
== 0)
118 memmove(begin
, end
+1, strlen(end
)+1);
119 else if (replace_len
!= len
+1)
120 memmove(end
+(replace_len
-len
-1), end
,
122 memcpy(begin
, newstr
, replace_len
);
125 static void substitute_line(char *line
)
127 char *ptr
, *name_ptr
, *end_ptr
;
128 struct subst_entry
*ent
;
133 * Expand all @FOO@ substitutions
137 name_ptr
= strchr(ptr
, '@');
140 if (*(++name_ptr
) == '@') {
142 * Handle tytso@@mit.edu --> tytso@mit.edu
144 memmove(name_ptr
-1, name_ptr
, strlen(name_ptr
)+1);
148 end_ptr
= strchr(name_ptr
, '@');
151 len
= end_ptr
- name_ptr
;
152 replace_name
= get_subst_symbol(name_ptr
, len
, 0);
157 ent
= fetch_subst_entry(replace_name
);
159 fprintf(stderr
, "Unfound expansion: '%s'\n",
165 fprintf(stderr
, "Replace name = '%s' with '%s'\n",
166 replace_name
, ent
->value
);
169 replace_string(ptr
, end_ptr
, ent
->value
);
170 if ((ent
->value
[0] == '@') &&
171 (strlen(replace_name
) == strlen(ent
->value
)-2) &&
172 !strncmp(replace_name
, ent
->value
+1,
173 strlen(ent
->value
)-2))
174 /* avoid an infinite loop */
175 ptr
+= strlen(ent
->value
);
178 * Now do a second pass to expand ${FOO}
182 name_ptr
= strchr(ptr
, '$');
185 if (*(++name_ptr
) != '{') {
190 end_ptr
= strchr(name_ptr
, '}');
193 len
= end_ptr
- name_ptr
;
194 replace_name
= get_subst_symbol(name_ptr
, len
, '$');
199 ent
= fetch_subst_entry(replace_name
);
205 fprintf(stderr
, "Replace name = '%s' with '%s'\n",
206 replace_name
, ent
->value
);
209 replace_string(ptr
, end_ptr
, ent
->value
);
213 static void parse_config_file(FILE *f
)
219 memset(line
, 0, sizeof(line
));
220 if (fgets(line
, sizeof(line
), f
) == NULL
)
223 * Strip newlines and comments.
225 cp
= strchr(line
, '\n');
228 cp
= strchr(line
, '#');
232 * Skip trailing and leading whitespace
234 for (cp
= line
+ strlen(line
) - 1; cp
>= line
; cp
--) {
235 if (*cp
== ' ' || *cp
== '\t')
241 while (*cp
&& isspace(*cp
))
250 * Ignore future extensions
255 * Parse substitutions
257 for (cp
= ptr
; *cp
; cp
++)
261 for (cp
++; *cp
; cp
++)
265 printf("Substitute: '%s' for '%s'\n", ptr
, cp
? cp
: "<NULL>");
272 * Return 0 if the files are different, 1 if the files are the same.
274 static int compare_file(FILE *old_f
, FILE *new_f
)
276 char oldbuf
[2048], newbuf
[2048], *oldcp
, *newcp
;
280 oldcp
= fgets(oldbuf
, sizeof(oldbuf
), old_f
);
281 newcp
= fgets(newbuf
, sizeof(newbuf
), new_f
);
282 if (!oldcp
&& !newcp
) {
286 if (!oldcp
|| !newcp
|| strcmp(oldbuf
, newbuf
)) {
296 int main(int argc
, char **argv
)
301 FILE *in
, *out
, *old
= NULL
;
302 char *outfn
= NULL
, *newfn
= NULL
;
304 int adjust_timestamp
= 0;
307 struct timeval tv
[2];
309 while ((c
= getopt (argc
, argv
, "f:tv")) != EOF
) {
312 in
= fopen(optarg
, "r");
317 parse_config_file(in
);
327 fprintf(stderr
, "%s: [-f config-file] [file]\n",
333 in
= fopen(argv
[optind
], "r");
335 perror(argv
[optind
]);
343 outfn
= argv
[optind
];
344 newfn
= (char *) malloc(strlen(outfn
)+20);
346 fprintf(stderr
, "Memory error! Exiting.\n");
349 strcpy(newfn
, outfn
);
350 strcat(newfn
, ".new");
351 fd
= open(newfn
, O_CREAT
|O_TRUNC
|O_RDWR
, 0444);
356 out
= fdopen(fd
, "w+");
362 fd
= open(outfn
, O_RDONLY
);
364 /* save the original atime, if possible */
365 if (fstat(fd
, &stbuf
) == 0) {
366 #if HAVE_STRUCT_STAT_ST_ATIM
367 tv
[0].tv_sec
= stbuf
.st_atim
.tv_sec
;
368 tv
[0].tv_usec
= stbuf
.st_atim
.tv_nsec
/ 1000;
370 tv
[0].tv_sec
= stbuf
.st_atime
;
375 old
= fdopen(fd
, "r");
385 if (fgets(line
, sizeof(line
), in
) == NULL
)
387 substitute_line(line
);
394 if (old
&& compare_file(old
, out
)) {
396 printf("No change, keeping %s.\n", outfn
);
397 if (adjust_timestamp
) {
399 printf("Updating modtime for %s\n", outfn
);
400 if (gettimeofday(&tv
[1], NULL
) < 0) {
401 perror("gettimeofday");
407 printf("Using original atime\n");
409 if (futimes(fileno(old
), tv
) < 0)
412 if (utimes(outfn
, tv
) < 0)
417 if (unlink(newfn
) < 0)
421 printf("Creating or replacing %s.\n", outfn
);
426 if (rename(newfn
, outfn
) < 0) {