1 // SPDX-License-Identifier: LGPL-2.1+
3 * This implementation is based on code from uClibc-0.9.30.3 but was
4 * modified and extended for use within U-Boot.
6 * Copyright (C) 2010-2013 Wolfgang Denk <wd@denx.de>
8 * Original license header:
10 * Copyright (C) 1993, 1995, 1996, 1997, 2002 Free Software Foundation, Inc.
11 * This file is part of the GNU C Library.
12 * Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1993.
18 #ifdef USE_HOSTCC /* HOST build */
25 # define debug(fmt,args...) printf(fmt ,##args)
27 # define debug(fmt,args...)
30 #else /* U-Boot build */
32 # include <linux/string.h>
33 # include <linux/ctype.h>
36 #ifndef CONFIG_ENV_MIN_ENTRIES /* minimum number of entries */
37 #define CONFIG_ENV_MIN_ENTRIES 64
39 #ifndef CONFIG_ENV_MAX_ENTRIES /* maximum number of entries */
40 #define CONFIG_ENV_MAX_ENTRIES 512
44 #define USED_DELETED -1
46 #include <env_callback.h>
47 #include <env_flags.h>
52 * [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
53 * [Knuth] The Art of Computer Programming, part 3 (6.4)
57 * The reentrant version has no static variables to maintain the state.
58 * Instead the interface of all functions is extended to take an argument
59 * which describes the current status.
62 typedef struct _ENTRY
{
68 static void _hdelete(const char *key
, struct hsearch_data
*htab
, ENTRY
*ep
,
76 * For the used double hash method the table size has to be a prime. To
77 * correct the user given table size we need a prime test. This trivial
78 * algorithm is adequate because
79 * a) the code is (most probably) called a few times per program run and
80 * b) the number is small because the table must fit in the core
82 static int isprime(unsigned int number
)
84 /* no even number will be passed */
87 while (div
* div
< number
&& number
% div
!= 0)
90 return number
% div
!= 0;
94 * Before using the hash table we must allocate memory for it.
95 * Test for an existing table are done. We allocate one element
96 * more as the found prime number says. This is done for more effective
97 * indexing as explained in the comment for the hsearch function.
98 * The contents of the table is zeroed, especially the field used
102 int hcreate_r(size_t nel
, struct hsearch_data
*htab
)
104 /* Test for correct arguments. */
110 /* There is still another table active. Return with error. */
111 if (htab
->table
!= NULL
)
114 /* Change nel to the first prime number not smaller as nel. */
115 nel
|= 1; /* make odd */
116 while (!isprime(nel
))
122 /* allocate memory and zero out */
123 htab
->table
= (_ENTRY
*) calloc(htab
->size
+ 1, sizeof(_ENTRY
));
124 if (htab
->table
== NULL
)
127 /* everything went alright */
137 * After using the hash table it has to be destroyed. The used memory can
138 * be freed and the local static variable can be marked as not used.
141 void hdestroy_r(struct hsearch_data
*htab
)
145 /* Test for correct arguments. */
151 /* free used memory */
152 for (i
= 1; i
<= htab
->size
; ++i
) {
153 if (htab
->table
[i
].used
> 0) {
154 ENTRY
*ep
= &htab
->table
[i
].entry
;
156 free((void *)ep
->key
);
162 /* the sign for an existing table is an value != NULL in htable */
171 * This is the search function. It uses double hashing with open addressing.
172 * The argument item.key has to be a pointer to an zero terminated, most
173 * probably strings of chars. The function for generating a number of the
174 * strings is simple but fast. It can be replaced by a more complex function
175 * like ajw (see [Aho,Sethi,Ullman]) if the needs are shown.
177 * We use an trick to speed up the lookup. The table is created by hcreate
178 * with one more element available. This enables us to use the index zero
179 * special. This index will never be used because we store the first hash
180 * index in the field used where zero means not used. Every other value
181 * means used. The used field can be used as a first fast comparison for
182 * equality of the stored and the parameter value. This helps to prevent
183 * unnecessary expensive calls of strcmp.
185 * This implementation differs from the standard library version of
186 * this function in a number of ways:
188 * - While the standard version does not make any assumptions about
189 * the type of the stored data objects at all, this implementation
190 * works with NUL terminated strings only.
191 * - Instead of storing just pointers to the original objects, we
192 * create local copies so the caller does not need to care about the
194 * - The standard implementation does not provide a way to update an
195 * existing entry. This version will create a new entry or update an
196 * existing one when both "action == ENTER" and "item.data != NULL".
197 * - Instead of returning 1 on success, we return the index into the
198 * internal hash table, which is also guaranteed to be positive.
199 * This allows us direct access to the found hash table slot for
200 * example for functions like hdelete().
203 int hmatch_r(const char *match
, int last_idx
, ENTRY
** retval
,
204 struct hsearch_data
*htab
)
207 size_t key_len
= strlen(match
);
209 for (idx
= last_idx
+ 1; idx
< htab
->size
; ++idx
) {
210 if (htab
->table
[idx
].used
<= 0)
212 if (!strncmp(match
, htab
->table
[idx
].entry
.key
, key_len
)) {
213 *retval
= &htab
->table
[idx
].entry
;
224 * Compare an existing entry with the desired key, and overwrite if the action
225 * is ENTER. This is simply a helper function for hsearch_r().
227 static inline int _compare_and_overwrite_entry(ENTRY item
, ACTION action
,
228 ENTRY
**retval
, struct hsearch_data
*htab
, int flag
,
229 unsigned int hval
, unsigned int idx
)
231 if (htab
->table
[idx
].used
== hval
232 && strcmp(item
.key
, htab
->table
[idx
].entry
.key
) == 0) {
233 /* Overwrite existing value? */
234 if ((action
== ENTER
) && (item
.data
!= NULL
)) {
235 /* check for permission */
236 if (htab
->change_ok
!= NULL
&& htab
->change_ok(
237 &htab
->table
[idx
].entry
, item
.data
,
238 env_op_overwrite
, flag
)) {
239 debug("change_ok() rejected setting variable "
240 "%s, skipping it!\n", item
.key
);
246 /* If there is a callback, call it */
247 if (htab
->table
[idx
].entry
.callback
&&
248 htab
->table
[idx
].entry
.callback(item
.key
,
249 item
.data
, env_op_overwrite
, flag
)) {
250 debug("callback() rejected setting variable "
251 "%s, skipping it!\n", item
.key
);
257 free(htab
->table
[idx
].entry
.data
);
258 htab
->table
[idx
].entry
.data
= strdup(item
.data
);
259 if (!htab
->table
[idx
].entry
.data
) {
265 /* return found entry */
266 *retval
= &htab
->table
[idx
].entry
;
273 int hsearch_r(ENTRY item
, ACTION action
, ENTRY
** retval
,
274 struct hsearch_data
*htab
, int flag
)
278 unsigned int len
= strlen(item
.key
);
280 unsigned int first_deleted
= 0;
283 /* Compute an value for the given string. Perhaps use a better method. */
286 while (count
-- > 0) {
288 hval
+= item
.key
[count
];
292 * First hash function:
293 * simply take the modul but prevent zero.
299 /* The first index tried. */
302 if (htab
->table
[idx
].used
) {
304 * Further action might be required according to the
309 if (htab
->table
[idx
].used
== USED_DELETED
313 ret
= _compare_and_overwrite_entry(item
, action
, retval
, htab
,
319 * Second hash function:
320 * as suggested in [Knuth]
322 hval2
= 1 + hval
% (htab
->size
- 2);
326 * Because SIZE is prime this guarantees to
327 * step through all available indices.
330 idx
= htab
->size
+ idx
- hval2
;
335 * If we visited all entries leave the loop
341 if (htab
->table
[idx
].used
== USED_DELETED
345 /* If entry is found use it. */
346 ret
= _compare_and_overwrite_entry(item
, action
, retval
,
347 htab
, flag
, hval
, idx
);
351 while (htab
->table
[idx
].used
!= USED_FREE
);
354 /* An empty bucket has been found. */
355 if (action
== ENTER
) {
357 * If table is full and another entry should be
358 * entered return with error.
360 if (htab
->filled
== htab
->size
) {
368 * create copies of item.key and item.data
373 htab
->table
[idx
].used
= hval
;
374 htab
->table
[idx
].entry
.key
= strdup(item
.key
);
375 htab
->table
[idx
].entry
.data
= strdup(item
.data
);
376 if (!htab
->table
[idx
].entry
.key
||
377 !htab
->table
[idx
].entry
.data
) {
385 /* This is a new entry, so look up a possible callback */
386 env_callback_init(&htab
->table
[idx
].entry
);
387 /* Also look for flags */
388 env_flags_init(&htab
->table
[idx
].entry
);
390 /* check for permission */
391 if (htab
->change_ok
!= NULL
&& htab
->change_ok(
392 &htab
->table
[idx
].entry
, item
.data
, env_op_create
, flag
)) {
393 debug("change_ok() rejected setting variable "
394 "%s, skipping it!\n", item
.key
);
395 _hdelete(item
.key
, htab
, &htab
->table
[idx
].entry
, idx
);
401 /* If there is a callback, call it */
402 if (htab
->table
[idx
].entry
.callback
&&
403 htab
->table
[idx
].entry
.callback(item
.key
, item
.data
,
404 env_op_create
, flag
)) {
405 debug("callback() rejected setting variable "
406 "%s, skipping it!\n", item
.key
);
407 _hdelete(item
.key
, htab
, &htab
->table
[idx
].entry
, idx
);
413 /* return new entry */
414 *retval
= &htab
->table
[idx
].entry
;
429 * The standard implementation of hsearch(3) does not provide any way
430 * to delete any entries from the hash table. We extend the code to
434 static void _hdelete(const char *key
, struct hsearch_data
*htab
, ENTRY
*ep
,
437 /* free used ENTRY */
438 debug("hdelete: DELETING key \"%s\"\n", key
);
439 free((void *)ep
->key
);
443 htab
->table
[idx
].used
= USED_DELETED
;
448 int hdelete_r(const char *key
, struct hsearch_data
*htab
, int flag
)
453 debug("hdelete: DELETE key \"%s\"\n", key
);
457 idx
= hsearch_r(e
, FIND
, &ep
, htab
, 0);
460 return 0; /* not found */
463 /* Check for permission */
464 if (htab
->change_ok
!= NULL
&&
465 htab
->change_ok(ep
, NULL
, env_op_delete
, flag
)) {
466 debug("change_ok() rejected deleting variable "
467 "%s, skipping it!\n", key
);
472 /* If there is a callback, call it */
473 if (htab
->table
[idx
].entry
.callback
&&
474 htab
->table
[idx
].entry
.callback(key
, NULL
, env_op_delete
, flag
)) {
475 debug("callback() rejected deleting variable "
476 "%s, skipping it!\n", key
);
481 _hdelete(key
, htab
, ep
, idx
);
486 #if !(defined(CONFIG_SPL_BUILD) && !defined(CONFIG_SPL_SAVEENV))
492 * Export the data stored in the hash table in linearized form.
494 * Entries are exported as "name=value" strings, separated by an
495 * arbitrary (non-NUL, of course) separator character. This allows to
496 * use this function both when formatting the U-Boot environment for
497 * external storage (using '\0' as separator), but also when using it
498 * for the "printenv" command to print all variables, simply by using
499 * as '\n" as separator. This can also be used for new features like
500 * exporting the environment data as text file, including the option
501 * for later re-import.
503 * The entries in the result list will be sorted by ascending key
506 * If the separator character is different from NUL, then any
507 * separator characters and backslash characters in the values will
508 * be escaped by a preceding backslash in output. This is needed for
509 * example to enable multi-line values, especially when the output
510 * shall later be parsed (for example, for re-import).
512 * There are several options how the result buffer is handled:
516 * NULL 0 A string of sufficient length will be allocated.
517 * NULL >0 A string of the size given will be
518 * allocated. An error will be returned if the size is
519 * not sufficient. Any unused bytes in the string will
521 * !NULL 0 The user-supplied buffer will be used. No length
522 * checking will be performed, i. e. it is assumed that
523 * the buffer size will always be big enough. DANGEROUS.
524 * !NULL >0 The user-supplied buffer will be used. An error will
525 * be returned if the size is not sufficient. Any unused
526 * bytes in the string will be '\0'-padded.
529 static int cmpkey(const void *p1
, const void *p2
)
531 ENTRY
*e1
= *(ENTRY
**) p1
;
532 ENTRY
*e2
= *(ENTRY
**) p2
;
534 return (strcmp(e1
->key
, e2
->key
));
537 static int match_string(int flag
, const char *str
, const char *pat
, void *priv
)
539 switch (flag
& H_MATCH_METHOD
) {
541 if (strcmp(str
, pat
) == 0)
545 if (strstr(str
, pat
))
551 struct slre
*slrep
= (struct slre
*)priv
;
553 if (slre_match(slrep
, str
, strlen(str
), NULL
))
559 printf("## ERROR: unsupported match method: 0x%02x\n",
560 flag
& H_MATCH_METHOD
);
566 static int match_entry(ENTRY
*ep
, int flag
,
567 int argc
, char * const argv
[])
572 for (arg
= 0; arg
< argc
; ++arg
) {
576 if (slre_compile(&slre
, argv
[arg
]) == 0) {
577 printf("Error compiling regex: %s\n", slre
.err_str
);
581 priv
= (void *)&slre
;
583 if (flag
& H_MATCH_KEY
) {
584 if (match_string(flag
, ep
->key
, argv
[arg
], priv
))
587 if (flag
& H_MATCH_DATA
) {
588 if (match_string(flag
, ep
->data
, argv
[arg
], priv
))
595 ssize_t
hexport_r(struct hsearch_data
*htab
, const char sep
, int flag
,
596 char **resp
, size_t size
,
597 int argc
, char * const argv
[])
599 ENTRY
*list
[htab
->size
];
604 /* Test for correct arguments. */
605 if ((resp
== NULL
) || (htab
== NULL
)) {
610 debug("EXPORT table = %p, htab.size = %d, htab.filled = %d, size = %lu\n",
611 htab
, htab
->size
, htab
->filled
, (ulong
)size
);
614 * search used entries,
615 * save addresses and compute total length
617 for (i
= 1, n
= 0, totlen
= 0; i
<= htab
->size
; ++i
) {
619 if (htab
->table
[i
].used
> 0) {
620 ENTRY
*ep
= &htab
->table
[i
].entry
;
621 int found
= match_entry(ep
, flag
, argc
, argv
);
623 if ((argc
> 0) && (found
== 0))
626 if ((flag
& H_HIDE_DOT
) && ep
->key
[0] == '.')
631 totlen
+= strlen(ep
->key
);
634 totlen
+= strlen(ep
->data
);
635 } else { /* check if escapes are needed */
640 /* add room for needed escape chars */
641 if ((*s
== sep
) || (*s
== '\\'))
646 totlen
+= 2; /* for '=' and 'sep' char */
651 /* Pass 1a: print unsorted list */
652 printf("Unsorted: n=%d\n", n
);
653 for (i
= 0; i
< n
; ++i
) {
654 printf("\t%3d: %p ==> %-10s => %s\n",
655 i
, list
[i
], list
[i
]->key
, list
[i
]->data
);
659 /* Sort list by keys */
660 qsort(list
, n
, sizeof(ENTRY
*), cmpkey
);
662 /* Check if the user supplied buffer size is sufficient */
664 if (size
< totlen
+ 1) { /* provided buffer too small */
665 printf("Env export buffer too small: %lu, but need %lu\n",
666 (ulong
)size
, (ulong
)totlen
+ 1);
674 /* Check if the user provided a buffer */
678 memset(res
, '\0', size
);
680 /* no, allocate and clear one */
681 *resp
= res
= calloc(1, size
);
689 * export sorted list of result data
691 for (i
= 0, p
= res
; i
< n
; ++i
) {
702 if ((*s
== sep
) || (*s
== '\\'))
703 *p
++ = '\\'; /* escape */
708 *p
= '\0'; /* terminate result */
720 * Check whether variable 'name' is amongst vars[],
721 * and remove all instances by setting the pointer to NULL
723 static int drop_var_from_set(const char *name
, int nvars
, char * vars
[])
728 /* No variables specified means process all of them */
732 for (i
= 0; i
< nvars
; i
++) {
735 /* If we found it, delete all of them */
736 if (!strcmp(name
, vars
[i
])) {
742 debug("Skipping non-listed variable %s\n", name
);
748 * Import linearized data into hash table.
750 * This is the inverse function to hexport(): it takes a linear list
751 * of "name=value" pairs and creates hash table entries from it.
753 * Entries without "value", i. e. consisting of only "name" or
754 * "name=", will cause this entry to be deleted from the hash table.
756 * The "flag" argument can be used to control the behaviour: when the
757 * H_NOCLEAR bit is set, then an existing hash table will kept, i. e.
758 * new data will be added to an existing hash table; otherwise, if no
759 * vars are passed, old data will be discarded and a new hash table
760 * will be created. If vars are passed, passed vars that are not in
761 * the linear list of "name=value" pairs will be removed from the
762 * current hash table.
764 * The separator character for the "name=value" pairs can be selected,
765 * so we both support importing from externally stored environment
766 * data (separated by NUL characters) and from plain text files
767 * (entries separated by newline characters).
769 * To allow for nicely formatted text input, leading white space
770 * (sequences of SPACE and TAB chars) is ignored, and entries starting
771 * (after removal of any leading white space) with a '#' character are
772 * considered comments and ignored.
774 * [NOTE: this means that a variable name cannot start with a '#'
777 * When using a non-NUL separator character, backslash is used as
778 * escape character in the value part, allowing for example for
781 * In theory, arbitrary separator characters can be used, but only
782 * '\0' and '\n' have really been tested.
785 int himport_r(struct hsearch_data
*htab
,
786 const char *env
, size_t size
, const char sep
, int flag
,
787 int crlf_is_lf
, int nvars
, char * const vars
[])
789 char *data
, *sp
, *dp
, *name
, *value
;
790 char *localvars
[nvars
];
793 /* Test for correct arguments. */
799 /* we allocate new space to make sure we can write to the array */
800 if ((data
= malloc(size
+ 1)) == NULL
) {
801 debug("himport_r: can't malloc %lu bytes\n", (ulong
)size
+ 1);
805 memcpy(data
, env
, size
);
809 /* make a local copy of the list of variables */
811 memcpy(localvars
, vars
, sizeof(vars
[0]) * nvars
);
813 if ((flag
& H_NOCLEAR
) == 0 && !nvars
) {
814 /* Destroy old hash table if one exists */
815 debug("Destroy Hash Table: %p table = %p\n", htab
,
822 * Create new hash table (if needed). The computation of the hash
823 * table size is based on heuristics: in a sample of some 70+
824 * existing systems we found an average size of 39+ bytes per entry
825 * in the environment (for the whole key=value pair). Assuming a
826 * size of 8 per entry (= safety factor of ~5) should provide enough
827 * safety margin for any existing environment definitions and still
828 * allow for more than enough dynamic additions. Note that the
829 * "size" argument is supposed to give the maximum environment size
830 * (CONFIG_ENV_SIZE). This heuristics will result in
831 * unreasonably large numbers (and thus memory footprint) for
832 * big flash environments (>8,000 entries for 64 KB
833 * environment size), so we clip it to a reasonable value.
834 * On the other hand we need to add some more entries for free
835 * space when importing very small buffers. Both boundaries can
836 * be overwritten in the board config file if needed.
840 int nent
= CONFIG_ENV_MIN_ENTRIES
+ size
/ 8;
842 if (nent
> CONFIG_ENV_MAX_ENTRIES
)
843 nent
= CONFIG_ENV_MAX_ENTRIES
;
845 debug("Create Hash Table: N=%d\n", nent
);
847 if (hcreate_r(nent
, htab
) == 0) {
855 return 1; /* everything OK */
858 /* Remove Carriage Returns in front of Line Feeds */
859 unsigned ignored_crs
= 0;
860 for(;dp
< data
+ size
&& *dp
; ++dp
) {
862 dp
< data
+ size
- 1 && *(dp
+1) == '\n')
865 *(dp
-ignored_crs
) = *dp
;
870 /* Parse environment; allow for '\0' and 'sep' as separators */
874 /* skip leading white space */
878 /* skip comment lines */
880 while (*dp
&& (*dp
!= sep
))
887 for (name
= dp
; *dp
!= '=' && *dp
&& *dp
!= sep
; ++dp
)
890 /* deal with "name" and "name=" entries (delete var) */
891 if (*dp
== '\0' || *(dp
+ 1) == '\0' ||
892 *dp
== sep
|| *(dp
+ 1) == sep
) {
895 *dp
++ = '\0'; /* terminate name */
897 debug("DELETE CANDIDATE: \"%s\"\n", name
);
898 if (!drop_var_from_set(name
, nvars
, localvars
))
901 if (hdelete_r(name
, htab
, flag
) == 0)
902 debug("DELETE ERROR ##############################\n");
906 *dp
++ = '\0'; /* terminate name */
908 /* parse value; deal with escapes */
909 for (value
= sp
= dp
; *dp
&& (*dp
!= sep
); ++dp
) {
910 if ((*dp
== '\\') && *(dp
+ 1))
914 *sp
++ = '\0'; /* terminate value */
918 debug("INSERT: unable to use an empty key\n");
924 /* Skip variables which are not supposed to be processed */
925 if (!drop_var_from_set(name
, nvars
, localvars
))
928 /* enter into hash table */
932 hsearch_r(e
, ENTER
, &rv
, htab
, flag
);
934 printf("himport_r: can't insert \"%s=%s\" into hash table\n",
937 debug("INSERT: table %p, filled %d/%d rv %p ==> name=\"%s\" value=\"%s\"\n",
938 htab
, htab
->filled
, htab
->size
,
940 } while ((dp
< data
+ size
) && *dp
); /* size check needed for text */
941 /* without '\0' termination */
942 debug("INSERT: free(data = %p)\n", data
);
945 if (flag
& H_NOCLEAR
)
948 /* process variables which were not considered */
949 for (i
= 0; i
< nvars
; i
++) {
950 if (localvars
[i
] == NULL
)
953 * All variables which were not deleted from the variable list
954 * were not present in the imported env
955 * This could mean two things:
956 * a) if the variable was present in current env, we delete it
957 * b) if the variable was not present in current env, we notify
960 if (hdelete_r(localvars
[i
], htab
, flag
) == 0)
961 printf("WARNING: '%s' neither in running nor in imported env!\n", localvars
[i
]);
963 printf("WARNING: '%s' not in imported env, deleting it!\n", localvars
[i
]);
967 debug("INSERT: done\n");
968 return 1; /* everything OK */
976 * Walk all of the entries in the hash, calling the callback for each one.
977 * this allows some generic operation to be performed on each element.
979 int hwalk_r(struct hsearch_data
*htab
, int (*callback
)(ENTRY
*))
984 for (i
= 1; i
<= htab
->size
; ++i
) {
985 if (htab
->table
[i
].used
> 0) {
986 retval
= callback(&htab
->table
[i
].entry
);