xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame] | 1 | /* Storage management for the chain of loaded shared objects. |
| 2 | Copyright (C) 1995-2016 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. */ |
| 29 | void |
| 30 | internal_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. */ |
| 57 | struct link_map * |
| 58 | internal_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 | } |