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path: root/modutils/modutils.c (plain)
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1/*
2 * Common modutils related functions for busybox
3 *
4 * Copyright (C) 2008 by Timo Teras <timo.teras@iki.fi>
5 *
6 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
7 */
8#include "modutils.h"
9
10#include <sys/syscall.h>
11
12#define init_module(mod, len, opts) syscall(__NR_init_module, mod, len, opts)
13#if defined(__NR_finit_module)
14# define finit_module(fd, uargs, flags) syscall(__NR_finit_module, fd, uargs, flags)
15#endif
16#define delete_module(mod, flags) syscall(__NR_delete_module, mod, flags)
17
18static module_entry *helper_get_module(module_db *db, const char *module, int create)
19{
20 char modname[MODULE_NAME_LEN];
21 struct module_entry *e;
22 unsigned i, hash;
23
24 filename2modname(module, modname);
25
26 hash = 0;
27 for (i = 0; modname[i]; i++)
28 hash = ((hash << 5) + hash) + modname[i];
29 hash %= MODULE_HASH_SIZE;
30
31 for (e = db->buckets[hash]; e; e = e->next)
32 if (strcmp(e->modname, modname) == 0)
33 return e;
34 if (!create)
35 return NULL;
36
37 e = xzalloc(sizeof(*e));
38 e->modname = xstrdup(modname);
39 e->next = db->buckets[hash];
40 db->buckets[hash] = e;
41 IF_DEPMOD(e->dnext = e->dprev = e;)
42
43 return e;
44}
45module_entry* FAST_FUNC moddb_get(module_db *db, const char *module)
46{
47 return helper_get_module(db, module, 0);
48}
49module_entry* FAST_FUNC moddb_get_or_create(module_db *db, const char *module)
50{
51 return helper_get_module(db, module, 1);
52}
53
54void FAST_FUNC moddb_free(module_db *db)
55{
56 module_entry *e, *n;
57 unsigned i;
58
59 for (i = 0; i < MODULE_HASH_SIZE; i++) {
60 for (e = db->buckets[i]; e; e = n) {
61 n = e->next;
62 free(e->name);
63 free(e->modname);
64 free(e);
65 }
66 }
67}
68
69void FAST_FUNC replace(char *s, char what, char with)
70{
71 while (*s) {
72 if (what == *s)
73 *s = with;
74 ++s;
75 }
76}
77
78char* FAST_FUNC replace_underscores(char *s)
79{
80 replace(s, '-', '_');
81 return s;
82}
83
84int FAST_FUNC string_to_llist(char *string, llist_t **llist, const char *delim)
85{
86 char *tok;
87 int len = 0;
88
89 while ((tok = strsep(&string, delim)) != NULL) {
90 if (tok[0] == '\0')
91 continue;
92 llist_add_to_end(llist, xstrdup(tok));
93 len += strlen(tok);
94 }
95 return len;
96}
97
98char* FAST_FUNC filename2modname(const char *filename, char *modname)
99{
100 char local_modname[MODULE_NAME_LEN];
101 int i;
102 const char *from;
103
104 if (filename == NULL)
105 return NULL;
106 if (modname == NULL)
107 modname = local_modname;
108 // Disabled since otherwise "modprobe dir/name" would work
109 // as if it is "modprobe name". It is unclear why
110 // 'basenamization' was here in the first place.
111 //from = bb_get_last_path_component_nostrip(filename);
112 from = filename;
113 for (i = 0; i < (MODULE_NAME_LEN-1) && from[i] != '\0' && from[i] != '.'; i++)
114 modname[i] = (from[i] == '-') ? '_' : from[i];
115 modname[i] = '\0';
116
117 if (modname == local_modname)
118 return xstrdup(modname);
119
120 return modname;
121}
122
123char* FAST_FUNC parse_cmdline_module_options(char **argv, int quote_spaces)
124{
125 char *options;
126 int optlen;
127
128 options = xzalloc(1);
129 optlen = 0;
130 while (*++argv) {
131 const char *fmt;
132 const char *var;
133 const char *val;
134
135 var = *argv;
136 options = xrealloc(options, optlen + 2 + strlen(var) + 2);
137 fmt = "%.*s%s ";
138 val = strchrnul(var, '=');
139 if (quote_spaces) {
140 /*
141 * modprobe (module-init-tools version 3.11.1) compat:
142 * quote only value:
143 * var="val with spaces", not "var=val with spaces"
144 * (note: var *name* is not checked for spaces!)
145 */
146 if (*val) { /* has var=val format. skip '=' */
147 val++;
148 if (strchr(val, ' '))
149 fmt = "%.*s\"%s\" ";
150 }
151 }
152 optlen += sprintf(options + optlen, fmt, (int)(val - var), var, val);
153 }
154 /* Remove trailing space. Disabled */
155 /* if (optlen != 0) options[optlen-1] = '\0'; */
156 return options;
157}
158
159#if ENABLE_FEATURE_INSMOD_TRY_MMAP
160void* FAST_FUNC try_to_mmap_module(const char *filename, size_t *image_size_p)
161{
162 /* We have user reports of failure to load 3MB module
163 * on a 16MB RAM machine. Apparently even a transient
164 * memory spike to 6MB during module load
165 * is too big for that system. */
166 void *image;
167 struct stat st;
168 int fd;
169
170 fd = xopen(filename, O_RDONLY);
171 fstat(fd, &st);
172 image = NULL;
173 /* st.st_size is off_t, we can't just pass it to mmap */
174 if (st.st_size <= *image_size_p) {
175 size_t image_size = st.st_size;
176 image = mmap(NULL, image_size, PROT_READ, MAP_PRIVATE, fd, 0);
177 if (image == MAP_FAILED) {
178 image = NULL;
179 } else if (*(uint32_t*)image != SWAP_BE32(0x7f454C46)) {
180 /* No ELF signature. Compressed module? */
181 munmap(image, image_size);
182 image = NULL;
183 } else {
184 /* Success. Report the size */
185 *image_size_p = image_size;
186 }
187 }
188 close(fd);
189 return image;
190}
191#endif
192
193/* Return:
194 * 0 on success,
195 * -errno on open/read error,
196 * errno on init_module() error
197 */
198int FAST_FUNC bb_init_module(const char *filename, const char *options)
199{
200 size_t image_size;
201 char *image;
202 int rc;
203 bool mmaped;
204
205 if (!options)
206 options = "";
207
208//TODO: audit bb_init_module_24 to match error code convention
209#if ENABLE_FEATURE_2_4_MODULES
210 if (get_linux_version_code() < KERNEL_VERSION(2,6,0))
211 return bb_init_module_24(filename, options);
212#endif
213
214 /*
215 * First we try finit_module if available. Some kernels are configured
216 * to only allow loading of modules off of secure storage (like a read-
217 * only rootfs) which needs the finit_module call. If it fails, we fall
218 * back to normal module loading to support compressed modules.
219 */
220# ifdef __NR_finit_module
221 {
222 int fd = open(filename, O_RDONLY | O_CLOEXEC);
223 if (fd >= 0) {
224 rc = finit_module(fd, options, 0) != 0;
225 close(fd);
226 if (rc == 0)
227 return rc;
228 }
229 }
230# endif
231
232 image_size = INT_MAX - 4095;
233 mmaped = 0;
234 image = try_to_mmap_module(filename, &image_size);
235 if (image) {
236 mmaped = 1;
237 } else {
238 errno = ENOMEM; /* may be changed by e.g. open errors below */
239 image = xmalloc_open_zipped_read_close(filename, &image_size);
240 if (!image)
241 return -errno;
242 }
243
244 errno = 0;
245 init_module(image, image_size, options);
246 rc = errno;
247 if (mmaped)
248 munmap(image, image_size);
249 else
250 free(image);
251 return rc;
252}
253
254int FAST_FUNC bb_delete_module(const char *module, unsigned int flags)
255{
256 errno = 0;
257 delete_module(module, flags);
258 return errno;
259}
260
261/* Note: not suitable for delete_module() errnos.
262 * For them, probably only EWOULDBLOCK needs explaining:
263 * "Other modules depend on us". So far we don't do such
264 * translation and don't use moderror() for removal errors.
265 */
266const char* FAST_FUNC moderror(int err)
267{
268 switch (err) {
269 case -1: /* btw: it's -EPERM */
270 return "no such module";
271 case ENOEXEC:
272 return "invalid module format";
273 case ENOENT:
274 return "unknown symbol in module, or unknown parameter";
275 case ESRCH:
276 return "module has wrong symbol version";
277 case ENOSYS:
278 return "kernel does not support requested operation";
279 }
280 if (err < 0) /* should always be */
281 err = -err;
282 return strerror(err);
283}
284
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