/* Storage management for the chain of loaded shared objects. Copyright (C) 1995-2017 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ #include <errno.h> #include <string.h> #include <stdlib.h> #include <unistd.h> #include <ldsodefs.h> #include <assert.h> /* Add the new link_map NEW to the end of the namespace list. */ void internal_function _dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid) { /* We modify the list of loaded objects. */ __rtld_lock_lock_recursive (GL(dl_load_write_lock)); if (GL(dl_ns)[nsid]._ns_loaded != NULL) { struct link_map *l = GL(dl_ns)[nsid]._ns_loaded; while (l->l_next != NULL) l = l->l_next; new->l_prev = l; /* new->l_next = NULL; Would be necessary but we use calloc. */ l->l_next = new; } else GL(dl_ns)[nsid]._ns_loaded = new; ++GL(dl_ns)[nsid]._ns_nloaded; new->l_serial = GL(dl_load_adds); ++GL(dl_load_adds); __rtld_lock_unlock_recursive (GL(dl_load_write_lock)); } /* Allocate a `struct link_map' for a new object being loaded, and enter it into the _dl_loaded list. */ struct link_map * internal_function _dl_new_object (char *realname, const char *libname, int type, struct link_map *loader, int mode, Lmid_t nsid) { size_t libname_len = strlen (libname) + 1; struct link_map *new; struct libname_list *newname; #ifdef SHARED /* We create the map for the executable before we know whether we have auditing libraries and if yes, how many. Assume the worst. */ unsigned int naudit = GLRO(dl_naudit) ?: ((mode & __RTLD_OPENEXEC) ? DL_NNS : 0); size_t audit_space = naudit * sizeof (new->l_audit[0]); #else # define audit_space 0 #endif new = (struct link_map *) calloc (sizeof (*new) + audit_space + sizeof (struct link_map *) + sizeof (*newname) + libname_len, 1); if (new == NULL) return NULL; new->l_real = new; new->l_symbolic_searchlist.r_list = (struct link_map **) ((char *) (new + 1) + audit_space); new->l_libname = newname = (struct libname_list *) (new->l_symbolic_searchlist.r_list + 1); newname->name = (char *) memcpy (newname + 1, libname, libname_len); /* newname->next = NULL; We use calloc therefore not necessary. */ newname->dont_free = 1; /* When we create the executable link map, or a VDSO link map, we start with "" for the l_name. In these cases "" points to ld.so rodata and won't get dumped during core file generation. Therefore to assist gdb and to create more self-contained core files we adjust l_name to point at the newly allocated copy (which will get dumped) instead of the ld.so rodata copy. */ new->l_name = *realname ? realname : (char *) newname->name + libname_len - 1; new->l_type = type; /* If we set the bit now since we know it is never used we avoid dirtying the cache line later. */ if ((GLRO(dl_debug_mask) & DL_DEBUG_UNUSED) == 0) new->l_used = 1; new->l_loader = loader; #if NO_TLS_OFFSET != 0 new->l_tls_offset = NO_TLS_OFFSET; #endif new->l_ns = nsid; #ifdef SHARED for (unsigned int cnt = 0; cnt < naudit; ++cnt) { new->l_audit[cnt].cookie = (uintptr_t) new; /* new->l_audit[cnt].bindflags = 0; */ } #endif /* new->l_global = 0; We use calloc therefore not necessary. */ /* Use the 'l_scope_mem' array by default for the 'l_scope' information. If we need more entries we will allocate a large array dynamically. */ new->l_scope = new->l_scope_mem; new->l_scope_max = sizeof (new->l_scope_mem) / sizeof (new->l_scope_mem[0]); /* Counter for the scopes we have to handle. */ int idx = 0; if (GL(dl_ns)[nsid]._ns_loaded != NULL) /* Add the global scope. */ new->l_scope[idx++] = &GL(dl_ns)[nsid]._ns_loaded->l_searchlist; /* If we have no loader the new object acts as it. */ if (loader == NULL) loader = new; else /* Determine the local scope. */ while (loader->l_loader != NULL) loader = loader->l_loader; /* Insert the scope if it isn't the global scope we already added. */ if (idx == 0 || &loader->l_searchlist != new->l_scope[0]) { if ((mode & RTLD_DEEPBIND) != 0 && idx != 0) { new->l_scope[1] = new->l_scope[0]; idx = 0; } new->l_scope[idx] = &loader->l_searchlist; } new->l_local_scope[0] = &new->l_searchlist; /* Don't try to find the origin for the main map which has the name "". */ if (realname[0] != '\0') { size_t realname_len = strlen (realname) + 1; char *origin; char *cp; if (realname[0] == '/') { /* It is an absolute path. Use it. But we have to make a copy since we strip out the trailing slash. */ cp = origin = (char *) malloc (realname_len); if (origin == NULL) { origin = (char *) -1; goto out; } } else { size_t len = realname_len; char *result = NULL; /* Get the current directory name. */ origin = NULL; do { char *new_origin; len += 128; new_origin = (char *) realloc (origin, len); if (new_origin == NULL) /* We exit the loop. Note that result == NULL. */ break; origin = new_origin; } while ((result = __getcwd (origin, len - realname_len)) == NULL && errno == ERANGE); if (result == NULL) { /* We were not able to determine the current directory. Note that free(origin) is OK if origin == NULL. */ free (origin); origin = (char *) -1; goto out; } /* Find the end of the path and see whether we have to add a slash. We could use rawmemchr but this need not be fast. */ cp = (strchr) (origin, '\0'); if (cp[-1] != '/') *cp++ = '/'; } /* Add the real file name. */ cp = __mempcpy (cp, realname, realname_len); /* Now remove the filename and the slash. Leave the slash if the name is something like "/foo". */ do --cp; while (*cp != '/'); if (cp == origin) /* Keep the only slash which is the first character. */ ++cp; *cp = '\0'; out: new->l_origin = origin; } return new; }