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170ab110 JH |
1 | /* |
2 | * (C) Copyright 2012 | |
3 | * Joe Hershberger, National Instruments, joe.hershberger@ni.com | |
4 | * | |
5 | * See file CREDITS for list of people who contributed to this | |
6 | * project. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License as | |
10 | * published by the Free Software Foundation; either version 2 of | |
11 | * the License, or (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, | |
21 | * MA 02111-1307 USA | |
22 | */ | |
23 | ||
24 | #include <common.h> | |
25 | #include <env_attr.h> | |
26 | #include <errno.h> | |
27 | #include <linux/string.h> | |
28 | #include <malloc.h> | |
29 | ||
30 | /* | |
31 | * Iterate through the whole list calling the callback for each found element. | |
32 | * "attr_list" takes the form: | |
33 | * attributes = [^,:\s]* | |
34 | * entry = name[:attributes] | |
35 | * list = entry[,list] | |
36 | */ | |
37 | int env_attr_walk(const char *attr_list, | |
38 | int (*callback)(const char *name, const char *attributes)) | |
39 | { | |
40 | const char *entry, *entry_end; | |
41 | char *name, *attributes; | |
42 | ||
43 | if (!attr_list) | |
44 | /* list not found */ | |
45 | return 1; | |
46 | ||
47 | entry = attr_list; | |
48 | do { | |
49 | char *entry_cpy = NULL; | |
50 | ||
51 | entry_end = strchr(entry, ENV_ATTR_LIST_DELIM); | |
52 | /* check if this is the last entry in the list */ | |
53 | if (entry_end == NULL) { | |
54 | int entry_len = strlen(entry); | |
55 | ||
56 | if (entry_len) { | |
57 | /* | |
58 | * allocate memory to copy the entry into since | |
59 | * we will need to inject '\0' chars and squash | |
60 | * white-space before calling the callback | |
61 | */ | |
62 | entry_cpy = malloc(entry_len + 1); | |
63 | if (entry_cpy) | |
64 | /* copy the rest of the list */ | |
65 | strcpy(entry_cpy, entry); | |
66 | else | |
67 | return -ENOMEM; | |
68 | } | |
69 | } else { | |
70 | int entry_len = entry_end - entry; | |
71 | ||
72 | if (entry_len) { | |
73 | /* | |
74 | * allocate memory to copy the entry into since | |
75 | * we will need to inject '\0' chars and squash | |
76 | * white-space before calling the callback | |
77 | */ | |
78 | entry_cpy = malloc(entry_len + 1); | |
79 | if (entry_cpy) { | |
80 | /* copy just this entry and null term */ | |
81 | strncpy(entry_cpy, entry, entry_len); | |
82 | entry_cpy[entry_len] = '\0'; | |
83 | } else | |
84 | return -ENOMEM; | |
85 | } | |
86 | } | |
87 | ||
88 | /* check if there is anything to process (e.g. not ",,,") */ | |
89 | if (entry_cpy != NULL) { | |
90 | attributes = strchr(entry_cpy, ENV_ATTR_SEP); | |
91 | /* check if there is a ':' */ | |
92 | if (attributes != NULL) { | |
93 | /* replace the ':' with '\0' to term name */ | |
94 | *attributes++ = '\0'; | |
95 | /* remove white-space from attributes */ | |
96 | attributes = strim(attributes); | |
97 | } | |
98 | /* remove white-space from name */ | |
99 | name = strim(entry_cpy); | |
100 | ||
101 | /* only call the callback if there is a name */ | |
102 | if (strlen(name) != 0) { | |
103 | int retval = 0; | |
104 | ||
105 | retval = callback(name, attributes); | |
106 | if (retval) { | |
107 | free(entry_cpy); | |
108 | return retval; | |
109 | } | |
110 | } | |
111 | } | |
112 | ||
113 | free(entry_cpy); | |
114 | entry = entry_end + 1; | |
115 | } while (entry_end != NULL); | |
116 | ||
117 | return 0; | |
118 | } | |
119 | ||
120 | /* | |
121 | * Search for the last matching string in another string with the option to | |
122 | * start looking at a certain point (i.e. ignore anything beyond that point). | |
123 | */ | |
124 | static char *reverse_strstr(const char *searched, const char *search_for, | |
125 | const char *searched_start) | |
126 | { | |
127 | char *result = NULL; | |
128 | ||
129 | if (*search_for == '\0') | |
130 | return (char *)searched; | |
131 | ||
132 | for (;;) { | |
133 | char *match = strstr(searched, search_for); | |
134 | ||
135 | /* | |
136 | * Stop looking if no new match is found or looking past the | |
137 | * searched_start pointer | |
138 | */ | |
139 | if (match == NULL || (searched_start != NULL && | |
140 | match + strlen(search_for) > searched_start)) | |
141 | break; | |
142 | ||
143 | result = match; | |
144 | searched = match + 1; | |
145 | } | |
146 | ||
147 | return result; | |
148 | } | |
149 | ||
150 | /* | |
151 | * Retrieve the attributes string associated with a single name in the list | |
152 | * There is no protection on attributes being too small for the value | |
153 | */ | |
154 | int env_attr_lookup(const char *attr_list, const char *name, char *attributes) | |
155 | { | |
156 | const char *entry = NULL; | |
157 | ||
158 | if (!attributes) | |
159 | /* bad parameter */ | |
160 | return -1; | |
161 | if (!attr_list) | |
162 | /* list not found */ | |
163 | return 1; | |
164 | ||
165 | entry = reverse_strstr(attr_list, name, NULL); | |
166 | while (entry != NULL) { | |
167 | const char *prevch = entry - 1; | |
168 | const char *nextch = entry + strlen(name); | |
169 | ||
170 | /* Skip spaces */ | |
171 | while (*prevch == ' ') | |
172 | prevch--; | |
173 | while (*nextch == ' ') | |
174 | nextch++; | |
175 | ||
176 | /* check for an exact match */ | |
177 | if ((entry == attr_list || | |
178 | *prevch == ENV_ATTR_LIST_DELIM) && | |
179 | (*nextch == ENV_ATTR_SEP || | |
180 | *nextch == ENV_ATTR_LIST_DELIM || | |
181 | *nextch == '\0')) | |
182 | break; | |
183 | ||
184 | entry = reverse_strstr(attr_list, name, entry); | |
185 | } | |
186 | if (entry != NULL) { | |
187 | int len; | |
188 | ||
189 | /* skip the name */ | |
190 | entry += strlen(name); | |
191 | /* skip spaces */ | |
192 | while (*entry == ' ') | |
193 | entry++; | |
194 | if (*entry != ENV_ATTR_SEP) | |
195 | len = 0; | |
196 | else { | |
197 | const char *delim; | |
198 | static const char delims[] = { | |
199 | ENV_ATTR_LIST_DELIM, ' ', '\0'}; | |
200 | ||
201 | /* skip the attr sep */ | |
202 | entry += 1; | |
203 | /* skip spaces */ | |
204 | while (*entry == ' ') | |
205 | entry++; | |
206 | ||
207 | delim = strpbrk(entry, delims); | |
208 | if (delim == NULL) | |
209 | len = strlen(entry); | |
210 | else | |
211 | len = delim - entry; | |
212 | memcpy(attributes, entry, len); | |
213 | } | |
214 | attributes[len] = '\0'; | |
215 | ||
216 | /* success */ | |
217 | return 0; | |
218 | } | |
219 | ||
220 | /* not found in list */ | |
221 | return 2; | |
222 | } |