blob: 64baca5a10a7e65df63fd7d4f7b097fa23f4be12 [file] [log] [blame]
Joe Hershberger170ab112012-12-11 22:16:24 -06001/*
2 * (C) Copyright 2012
3 * Joe Hershberger, National Instruments, joe.hershberger@ni.com
4 *
Wolfgang Denk1a459662013-07-08 09:37:19 +02005 * SPDX-License-Identifier: GPL-2.0+
Joe Hershberger170ab112012-12-11 22:16:24 -06006 */
7
Joe Hershberger30fd4fad2012-12-11 22:16:32 -06008#ifdef USE_HOSTCC /* Eliminate "ANSI does not permit..." warnings */
9#include <stdint.h>
10#include <stdio.h>
11#include <linux/linux_string.h>
12#else
Joe Hershberger170ab112012-12-11 22:16:24 -060013#include <common.h>
Joe Hershberger30fd4fad2012-12-11 22:16:32 -060014#endif
15
Joe Hershberger170ab112012-12-11 22:16:24 -060016#include <env_attr.h>
17#include <errno.h>
18#include <linux/string.h>
19#include <malloc.h>
20
21/*
22 * Iterate through the whole list calling the callback for each found element.
23 * "attr_list" takes the form:
24 * attributes = [^,:\s]*
25 * entry = name[:attributes]
26 * list = entry[,list]
27 */
28int env_attr_walk(const char *attr_list,
29 int (*callback)(const char *name, const char *attributes))
30{
31 const char *entry, *entry_end;
32 char *name, *attributes;
33
34 if (!attr_list)
35 /* list not found */
36 return 1;
37
38 entry = attr_list;
39 do {
40 char *entry_cpy = NULL;
41
42 entry_end = strchr(entry, ENV_ATTR_LIST_DELIM);
43 /* check if this is the last entry in the list */
44 if (entry_end == NULL) {
45 int entry_len = strlen(entry);
46
47 if (entry_len) {
48 /*
49 * allocate memory to copy the entry into since
50 * we will need to inject '\0' chars and squash
51 * white-space before calling the callback
52 */
53 entry_cpy = malloc(entry_len + 1);
54 if (entry_cpy)
55 /* copy the rest of the list */
56 strcpy(entry_cpy, entry);
57 else
58 return -ENOMEM;
59 }
60 } else {
61 int entry_len = entry_end - entry;
62
63 if (entry_len) {
64 /*
65 * allocate memory to copy the entry into since
66 * we will need to inject '\0' chars and squash
67 * white-space before calling the callback
68 */
69 entry_cpy = malloc(entry_len + 1);
70 if (entry_cpy) {
71 /* copy just this entry and null term */
72 strncpy(entry_cpy, entry, entry_len);
73 entry_cpy[entry_len] = '\0';
74 } else
75 return -ENOMEM;
76 }
77 }
78
79 /* check if there is anything to process (e.g. not ",,,") */
80 if (entry_cpy != NULL) {
81 attributes = strchr(entry_cpy, ENV_ATTR_SEP);
82 /* check if there is a ':' */
83 if (attributes != NULL) {
84 /* replace the ':' with '\0' to term name */
85 *attributes++ = '\0';
86 /* remove white-space from attributes */
87 attributes = strim(attributes);
88 }
89 /* remove white-space from name */
90 name = strim(entry_cpy);
91
92 /* only call the callback if there is a name */
93 if (strlen(name) != 0) {
94 int retval = 0;
95
96 retval = callback(name, attributes);
97 if (retval) {
98 free(entry_cpy);
99 return retval;
100 }
101 }
102 }
103
104 free(entry_cpy);
105 entry = entry_end + 1;
106 } while (entry_end != NULL);
107
108 return 0;
109}
110
111/*
112 * Search for the last matching string in another string with the option to
113 * start looking at a certain point (i.e. ignore anything beyond that point).
114 */
115static char *reverse_strstr(const char *searched, const char *search_for,
116 const char *searched_start)
117{
118 char *result = NULL;
119
120 if (*search_for == '\0')
121 return (char *)searched;
122
123 for (;;) {
124 char *match = strstr(searched, search_for);
125
126 /*
127 * Stop looking if no new match is found or looking past the
128 * searched_start pointer
129 */
130 if (match == NULL || (searched_start != NULL &&
131 match + strlen(search_for) > searched_start))
132 break;
133
134 result = match;
135 searched = match + 1;
136 }
137
138 return result;
139}
140
141/*
142 * Retrieve the attributes string associated with a single name in the list
143 * There is no protection on attributes being too small for the value
144 */
145int env_attr_lookup(const char *attr_list, const char *name, char *attributes)
146{
147 const char *entry = NULL;
148
149 if (!attributes)
150 /* bad parameter */
151 return -1;
152 if (!attr_list)
153 /* list not found */
154 return 1;
155
156 entry = reverse_strstr(attr_list, name, NULL);
157 while (entry != NULL) {
158 const char *prevch = entry - 1;
159 const char *nextch = entry + strlen(name);
160
161 /* Skip spaces */
162 while (*prevch == ' ')
163 prevch--;
164 while (*nextch == ' ')
165 nextch++;
166
167 /* check for an exact match */
168 if ((entry == attr_list ||
169 *prevch == ENV_ATTR_LIST_DELIM) &&
170 (*nextch == ENV_ATTR_SEP ||
171 *nextch == ENV_ATTR_LIST_DELIM ||
172 *nextch == '\0'))
173 break;
174
175 entry = reverse_strstr(attr_list, name, entry);
176 }
177 if (entry != NULL) {
178 int len;
179
180 /* skip the name */
181 entry += strlen(name);
182 /* skip spaces */
183 while (*entry == ' ')
184 entry++;
185 if (*entry != ENV_ATTR_SEP)
186 len = 0;
187 else {
188 const char *delim;
189 static const char delims[] = {
190 ENV_ATTR_LIST_DELIM, ' ', '\0'};
191
192 /* skip the attr sep */
193 entry += 1;
194 /* skip spaces */
195 while (*entry == ' ')
196 entry++;
197
198 delim = strpbrk(entry, delims);
199 if (delim == NULL)
200 len = strlen(entry);
201 else
202 len = delim - entry;
203 memcpy(attributes, entry, len);
204 }
205 attributes[len] = '\0';
206
207 /* success */
208 return 0;
209 }
210
211 /* not found in list */
212 return 2;
213}