1/* Storage management for the chain of loaded shared objects.
2 Copyright (C) 1995-2017 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <string.h>
21#include <stdlib.h>
22#include <unistd.h>
23#include <ldsodefs.h>
24
25#include <assert.h>
26
27
28/* Add the new link_map NEW to the end of the namespace list. */
29void
30internal_function
31_dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)
32{
33 /* We modify the list of loaded objects. */
34 __rtld_lock_lock_recursive (GL(dl_load_write_lock));
35
36 if (GL(dl_ns)[nsid]._ns_loaded != NULL)
37 {
38 struct link_map *l = GL(dl_ns)[nsid]._ns_loaded;
39 while (l->l_next != NULL)
40 l = l->l_next;
41 new->l_prev = l;
42 /* new->l_next = NULL; Would be necessary but we use calloc. */
43 l->l_next = new;
44 }
45 else
46 GL(dl_ns)[nsid]._ns_loaded = new;
47 ++GL(dl_ns)[nsid]._ns_nloaded;
48 new->l_serial = GL(dl_load_adds);
49 ++GL(dl_load_adds);
50
51 __rtld_lock_unlock_recursive (GL(dl_load_write_lock));
52}
53
54
55/* Allocate a `struct link_map' for a new object being loaded,
56 and enter it into the _dl_loaded list. */
57struct link_map *
58internal_function
59_dl_new_object (char *realname, const char *libname, int type,
60 struct link_map *loader, int mode, Lmid_t nsid)
61{
62 size_t libname_len = strlen (libname) + 1;
63 struct link_map *new;
64 struct libname_list *newname;
65#ifdef SHARED
66 /* We create the map for the executable before we know whether we have
67 auditing libraries and if yes, how many. Assume the worst. */
68 unsigned int naudit = GLRO(dl_naudit) ?: ((mode & __RTLD_OPENEXEC)
69 ? DL_NNS : 0);
70 size_t audit_space = naudit * sizeof (new->l_audit[0]);
71#else
72# define audit_space 0
73#endif
74
75 new = (struct link_map *) calloc (sizeof (*new) + audit_space
76 + sizeof (struct link_map *)
77 + sizeof (*newname) + libname_len, 1);
78 if (new == NULL)
79 return NULL;
80
81 new->l_real = new;
82 new->l_symbolic_searchlist.r_list = (struct link_map **) ((char *) (new + 1)
83 + audit_space);
84
85 new->l_libname = newname
86 = (struct libname_list *) (new->l_symbolic_searchlist.r_list + 1);
87 newname->name = (char *) memcpy (newname + 1, libname, libname_len);
88 /* newname->next = NULL; We use calloc therefore not necessary. */
89 newname->dont_free = 1;
90
91 /* When we create the executable link map, or a VDSO link map, we start
92 with "" for the l_name. In these cases "" points to ld.so rodata
93 and won't get dumped during core file generation. Therefore to assist
94 gdb and to create more self-contained core files we adjust l_name to
95 point at the newly allocated copy (which will get dumped) instead of
96 the ld.so rodata copy. */
97 new->l_name = *realname ? realname : (char *) newname->name + libname_len - 1;
98 new->l_type = type;
99 /* If we set the bit now since we know it is never used we avoid
100 dirtying the cache line later. */
101 if ((GLRO(dl_debug_mask) & DL_DEBUG_UNUSED) == 0)
102 new->l_used = 1;
103 new->l_loader = loader;
104#if NO_TLS_OFFSET != 0
105 new->l_tls_offset = NO_TLS_OFFSET;
106#endif
107 new->l_ns = nsid;
108
109#ifdef SHARED
110 for (unsigned int cnt = 0; cnt < naudit; ++cnt)
111 {
112 new->l_audit[cnt].cookie = (uintptr_t) new;
113 /* new->l_audit[cnt].bindflags = 0; */
114 }
115#endif
116
117 /* new->l_global = 0; We use calloc therefore not necessary. */
118
119 /* Use the 'l_scope_mem' array by default for the 'l_scope'
120 information. If we need more entries we will allocate a large
121 array dynamically. */
122 new->l_scope = new->l_scope_mem;
123 new->l_scope_max = sizeof (new->l_scope_mem) / sizeof (new->l_scope_mem[0]);
124
125 /* Counter for the scopes we have to handle. */
126 int idx = 0;
127
128 if (GL(dl_ns)[nsid]._ns_loaded != NULL)
129 /* Add the global scope. */
130 new->l_scope[idx++] = &GL(dl_ns)[nsid]._ns_loaded->l_searchlist;
131
132 /* If we have no loader the new object acts as it. */
133 if (loader == NULL)
134 loader = new;
135 else
136 /* Determine the local scope. */
137 while (loader->l_loader != NULL)
138 loader = loader->l_loader;
139
140 /* Insert the scope if it isn't the global scope we already added. */
141 if (idx == 0 || &loader->l_searchlist != new->l_scope[0])
142 {
143 if ((mode & RTLD_DEEPBIND) != 0 && idx != 0)
144 {
145 new->l_scope[1] = new->l_scope[0];
146 idx = 0;
147 }
148
149 new->l_scope[idx] = &loader->l_searchlist;
150 }
151
152 new->l_local_scope[0] = &new->l_searchlist;
153
154 /* Don't try to find the origin for the main map which has the name "". */
155 if (realname[0] != '\0')
156 {
157 size_t realname_len = strlen (realname) + 1;
158 char *origin;
159 char *cp;
160
161 if (realname[0] == '/')
162 {
163 /* It is an absolute path. Use it. But we have to make a
164 copy since we strip out the trailing slash. */
165 cp = origin = (char *) malloc (realname_len);
166 if (origin == NULL)
167 {
168 origin = (char *) -1;
169 goto out;
170 }
171 }
172 else
173 {
174 size_t len = realname_len;
175 char *result = NULL;
176
177 /* Get the current directory name. */
178 origin = NULL;
179 do
180 {
181 char *new_origin;
182
183 len += 128;
184 new_origin = (char *) realloc (origin, len);
185 if (new_origin == NULL)
186 /* We exit the loop. Note that result == NULL. */
187 break;
188 origin = new_origin;
189 }
190 while ((result = __getcwd (origin, len - realname_len)) == NULL
191 && errno == ERANGE);
192
193 if (result == NULL)
194 {
195 /* We were not able to determine the current directory.
196 Note that free(origin) is OK if origin == NULL. */
197 free (origin);
198 origin = (char *) -1;
199 goto out;
200 }
201
202 /* Find the end of the path and see whether we have to add a
203 slash. We could use rawmemchr but this need not be
204 fast. */
205 cp = (strchr) (origin, '\0');
206 if (cp[-1] != '/')
207 *cp++ = '/';
208 }
209
210 /* Add the real file name. */
211 cp = __mempcpy (cp, realname, realname_len);
212
213 /* Now remove the filename and the slash. Leave the slash if
214 the name is something like "/foo". */
215 do
216 --cp;
217 while (*cp != '/');
218
219 if (cp == origin)
220 /* Keep the only slash which is the first character. */
221 ++cp;
222 *cp = '\0';
223
224 out:
225 new->l_origin = origin;
226 }
227
228 return new;
229}
230