summaryrefslogtreecommitdiff
path: root/src/drivers/vpd/lib_vpd.h
blob: 7a7566b234671a497e2d2445458f98d23e6c6320 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
/*
 * Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 *
 */

#ifndef __LIB_VPD__
#define __LIB_VPD__

#include <inttypes.h>

enum {
	VPD_OK = 0,
	VPD_FAIL,
};

enum {
	VPD_TYPE_TERMINATOR = 0,
	VPD_TYPE_STRING,
	VPD_TYPE_INFO                = 0xfe,
	VPD_TYPE_IMPLICIT_TERMINATOR = 0xff,
};

enum {
	VPD_AS_LONG_AS = -1,
};

enum {  /* export_type */
	VPD_EXPORT_KEY_VALUE = 1,
	VPD_EXPORT_VALUE,
	VPD_EXPORT_AS_PARAMETER,
};

/* Callback for decodeVpdString to invoke. */
typedef int VpdDecodeCallback(const uint8_t *key, int32_t key_len,
                              const uint8_t *value, int32_t value_len,
                              void *arg);

/* Container data types */
struct StringPair {
	uint8_t *key;
	uint8_t *value;
	int pad_len;
	int filter_out;  /* TRUE means not exported. */
	struct StringPair *next;
};

struct PairContainer {
	struct StringPair *first;
};


/***********************************************************************
 * Encode and decode VPD entries
 ***********************************************************************/

/* Encodes the len into multiple bytes with the following format.
 *
 *    7   6 ............ 0
 *  +----+------------------+
 *  |More|      Length      |  ...
 *  +----+------------------+
 *
 * The encode_buf points to the actual position we are going to store.
 * encoded_len will return the exact bytes we encoded in this function.
 * Returns fail if the buffer is not long enough.
 */
int encodeLen(
    const int32_t len,
    uint8_t *encode_buf,
    const int32_t max_len,
    int32_t *encoded_len);

/* Given an encoded string, this functions decodes the length field which varies
 * from 1 byte to many bytes.
 *
 * The in points the actual byte going to be decoded. The *length returns
 * the decoded length field. The number of consumed bytes will be stroed in
 * decoded_len.
 *
 * Returns VPD_FAIL if more bit is 1, but actually reaches the end of string.
 */
int decodeLen(
    const int32_t max_len,
    const uint8_t *in,
    int32_t *length,
    int32_t *decoded_len);


/* Encodes the terminator.
 * When calling, the output_buf should point to the start of buffer while
 * *generated_len should contain how many bytes exist in buffer now.
 * After return, *generated_len would be plused the number of bytes generated
 * in this function.
 */
int encodeVpdTerminator(
    const int max_buffer_len,
    uint8_t *output_buf,
    int *generated_len);

/* Encodes the given type/key/value pair into buffer.
 *
 * The pad_value_len is used to control the output value length.
 * When pad_value_len > 0, the value is outputted into fixed length (pad \0
 *                         if the value is shorter). Truncated if too long.
 *      pad_value_len == VPD_NO_LIMIT, output the value as long as possible.
 * This is useful when we want to fix the structure layout at beginning.
 *
 * The encoded string will be stored in output_buf. If it is longer than
 * max_buffer_len, this function returns fail. If the buffer is long enough,
 * the generated_len will be updated.
 *
 * When calling, the output_buf should point to the start of buffer while
 * *generated_len should contain how many bytes exist in buffer now.
 * After return, *generated_len would be plused the number of bytes generated
 * in this function.
 *
 * The initial value of *generated_len can be non-zero, so that this value
 * can be used between multiple calls to encodeVpd2Pair().
 */
int encodeVpdString(
    const uint8_t *key,
    const uint8_t *value,
    const int pad_value_len,
    const int max_buffer_len,
    uint8_t *output_buf,
    int *generated_len);


/* Given the encoded string, this function invokes callback with extracted
 * (key, value). The *consumed will be plused the number of bytes consumed in
 * this function.
 *
 * The input_buf points to the first byte of the input buffer.
 *
 * The *consumed starts from 0, which is actually the next byte to be decoded.
 * It can be non-zero to be used in multiple calls.
 *
 * If one entry is successfully decoded, sends it to callback and returns the
 * result.
 */
int decodeVpdString(
    const int32_t max_len,
    const uint8_t *input_buf,
    int32_t *consumed,
    VpdDecodeCallback callback,
    void *callback_arg);

/***********************************************************************
 * Container helpers
 ***********************************************************************/
void initContainer(struct PairContainer *container);

struct StringPair *findString(struct PairContainer *container,
                              const uint8_t *key,
                              struct StringPair ***prev_next);

/* If key is already existed in container, its value will be replaced.
 * If not existed, creates new entry in container.
 */
void setString(struct PairContainer *container,
               const uint8_t *key,
               const uint8_t *value,
               const int pad_len);

/* merge all entries in src into dst. If key is duplicate, overwrite it.
 */
void mergeContainer(struct PairContainer *dst,
                    const struct PairContainer *src);

/* subtract src from dst.
*/
int subtractContainer(struct PairContainer *dst,
                      const struct PairContainer *src);

/* Given a container, encode its all entries into the buffer.
 */
int encodeContainer(const struct PairContainer *container,
                    const int max_buf_len,
                    uint8_t *buf,
                    int *generated);

/* Given a VPD blob, decode its entries and push into container.
 */
int decodeToContainer(struct PairContainer *container,
                      const int32_t max_len,
                      const uint8_t *input_buf,
                      int32_t *consumed);

/* Set filter for exporting functions.
 * If filter is NULL, resets the filter so that everything can be exported.
 */
int setContainerFilter(struct PairContainer *container,
                       const uint8_t *filter);

/*
 * Remove a key.
 * Returns VPD_OK if deleted successfully. Otherwise, VPD_FAIL.
 */
int deleteKey(struct PairContainer *container,
              const uint8_t *key);

/*
 * Returns number of pairs in container.
 */
int lenOfContainer(const struct PairContainer *container);

/*
 * Export the container content with human-readable text.
 *
 * The buf points to the first byte of buffer and *generated contains the number
 * of bytes already existed in buffer.
 *
 * Afterward, the *generated will be plused on exact bytes this function has
 * generated.
 */
int exportContainer(const int export_type,
                    const struct PairContainer *container,
                    const int max_buf_len,
                    uint8_t *buf,
                    int *generated);

void destroyContainer(struct PairContainer *container);

#endif  /* __LIB_VPD__ */