fix build warnings
[qemu/aliguori-queue.git] / linux-user / envlist.c
blobe13c2d3e1402a55c3b396aace7a26cc19cd9dc19
1 #include <sys/queue.h>
3 #include <assert.h>
4 #include <errno.h>
5 #include <stdlib.h>
6 #include <string.h>
7 #include <unistd.h>
9 #include "envlist.h"
11 struct envlist_entry {
12 const char *ev_var; /* actual env value */
13 LIST_ENTRY(envlist_entry) ev_link;
16 struct envlist {
17 LIST_HEAD(, envlist_entry) el_entries; /* actual entries */
18 size_t el_count; /* number of entries */
21 static int envlist_parse(envlist_t *envlist,
22 const char *env, int (*)(envlist_t *, const char *));
25 * Allocates new envlist and returns pointer to that or
26 * NULL in case of error.
28 envlist_t *
29 envlist_create(void)
31 envlist_t *envlist;
33 if ((envlist = malloc(sizeof (*envlist))) == NULL)
34 return (NULL);
36 LIST_INIT(&envlist->el_entries);
37 envlist->el_count = 0;
39 return (envlist);
43 * Releases given envlist and its entries.
45 void
46 envlist_free(envlist_t *envlist)
48 struct envlist_entry *entry;
50 assert(envlist != NULL);
52 while (envlist->el_entries.lh_first != NULL) {
53 entry = envlist->el_entries.lh_first;
54 LIST_REMOVE(entry, ev_link);
56 free((char *)entry->ev_var);
57 free(entry);
59 free(envlist);
63 * Parses comma separated list of set/modify environment
64 * variable entries and updates given enlist accordingly.
66 * For example:
67 * envlist_parse(el, "HOME=foo,SHELL=/bin/sh");
69 * inserts/sets environment variables HOME and SHELL.
71 * Returns 0 on success, errno otherwise.
73 int
74 envlist_parse_set(envlist_t *envlist, const char *env)
76 return (envlist_parse(envlist, env, &envlist_setenv));
80 * Parses comma separated list of unset environment variable
81 * entries and removes given variables from given envlist.
83 * Returns 0 on success, errno otherwise.
85 int
86 envlist_parse_unset(envlist_t *envlist, const char *env)
88 return (envlist_parse(envlist, env, &envlist_unsetenv));
92 * Parses comma separated list of set, modify or unset entries
93 * and calls given callback for each entry.
95 * Returns 0 in case of success, errno otherwise.
97 static int
98 envlist_parse(envlist_t *envlist, const char *env,
99 int (*callback)(envlist_t *, const char *))
101 char *tmpenv, *envvar;
102 char *envsave = NULL;
104 assert(callback != NULL);
106 if ((envlist == NULL) || (env == NULL))
107 return (EINVAL);
110 * We need to make temporary copy of the env string
111 * as strtok_r(3) modifies it while it tokenizes.
113 if ((tmpenv = strdup(env)) == NULL)
114 return (errno);
116 envvar = strtok_r(tmpenv, ",", &envsave);
117 while (envvar != NULL) {
118 if ((*callback)(envlist, envvar) != 0) {
119 free(tmpenv);
120 return (errno);
122 envvar = strtok_r(NULL, ",", &envsave);
125 free(tmpenv);
126 return (0);
130 * Sets environment value to envlist in similar manner
131 * than putenv(3).
133 * Returns 0 in success, errno otherwise.
136 envlist_setenv(envlist_t *envlist, const char *env)
138 struct envlist_entry *entry = NULL;
139 const char *eq_sign;
140 size_t envname_len;
142 if ((envlist == NULL) || (env == NULL))
143 return (EINVAL);
145 /* find out first equals sign in given env */
146 if ((eq_sign = strchr(env, '=')) == NULL)
147 return (EINVAL);
148 envname_len = eq_sign - env + 1;
151 * If there already exists variable with given name
152 * we remove and release it before allocating a whole
153 * new entry.
155 for (entry = envlist->el_entries.lh_first; entry != NULL;
156 entry = entry->ev_link.le_next) {
157 if (strncmp(entry->ev_var, env, envname_len) == 0)
158 break;
161 if (entry != NULL) {
162 LIST_REMOVE(entry, ev_link);
163 free((char *)entry->ev_var);
164 free(entry);
165 } else {
166 envlist->el_count++;
169 if ((entry = malloc(sizeof (*entry))) == NULL)
170 return (errno);
171 if ((entry->ev_var = strdup(env)) == NULL) {
172 free(entry);
173 return (errno);
175 LIST_INSERT_HEAD(&envlist->el_entries, entry, ev_link);
177 return (0);
181 * Removes given env value from envlist in similar manner
182 * than unsetenv(3). Returns 0 in success, errno otherwise.
185 envlist_unsetenv(envlist_t *envlist, const char *env)
187 struct envlist_entry *entry;
188 size_t envname_len;
190 if ((envlist == NULL) || (env == NULL))
191 return (EINVAL);
193 /* env is not allowed to contain '=' */
194 if (strchr(env, '=') != NULL)
195 return (EINVAL);
198 * Find out the requested entry and remove
199 * it from the list.
201 envname_len = strlen(env);
202 for (entry = envlist->el_entries.lh_first; entry != NULL;
203 entry = entry->ev_link.le_next) {
204 if (strncmp(entry->ev_var, env, envname_len) == 0)
205 break;
207 if (entry != NULL) {
208 LIST_REMOVE(entry, ev_link);
209 free((char *)entry->ev_var);
210 free(entry);
212 envlist->el_count--;
214 return (0);
218 * Returns given envlist as array of strings (in same form that
219 * global variable environ is). Caller must free returned memory
220 * by calling free(3) for each element and for the array. Returned
221 * array and given envlist are not related (no common references).
223 * If caller provides count pointer, number of items in array is
224 * stored there. In case of error, NULL is returned and no memory
225 * is allocated.
227 char **
228 envlist_to_environ(const envlist_t *envlist, size_t *count)
230 struct envlist_entry *entry;
231 char **env, **penv;
233 penv = env = malloc((envlist->el_count + 1) * sizeof (char *));
234 if (env == NULL)
235 return (NULL);
237 for (entry = envlist->el_entries.lh_first; entry != NULL;
238 entry = entry->ev_link.le_next) {
239 *(penv++) = strdup(entry->ev_var);
241 *penv = NULL; /* NULL terminate the list */
243 if (count != NULL)
244 *count = envlist->el_count;
246 return (env);