2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 * Dynamic linker for ELF.
31 * John Polstra <jdp@polstra.com>.
35 #error "GCC is needed to compile this file"
38 #include <sys/param.h>
55 #define END_SYM "_end"
56 #define PATH_RTLD "/usr/libexec/ld-elf.so.1"
59 typedef void (*func_ptr_type)();
62 * This structure provides a reentrant way to keep a list of objects and
63 * check which ones have already been processed in some way.
65 typedef struct Struct_DoneList {
66 const Obj_Entry **objs; /* Array of object pointers */
67 unsigned int num_alloc; /* Allocated size of the array */
68 unsigned int num_used; /* Number of array slots used */
72 * Function declarations.
74 static const char *basename(const char *);
75 static void die(void);
76 static void digest_dynamic(Obj_Entry *);
77 static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *);
78 static Obj_Entry *dlcheck(void *);
79 static bool donelist_check(DoneList *, const Obj_Entry *);
80 static char *find_library(const char *, const Obj_Entry *);
81 static const char *gethints(void);
82 static void init_dag(Obj_Entry *);
83 static void init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *);
84 static void init_rtld(caddr_t);
85 static void initlist_add_neededs(Needed_Entry *needed, Objlist *list);
86 static void initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail,
88 static bool is_exported(const Elf_Sym *);
89 static void linkmap_add(Obj_Entry *);
90 static void linkmap_delete(Obj_Entry *);
91 static int load_needed_objects(Obj_Entry *);
92 static int load_preload_objects(void);
93 static Obj_Entry *load_object(char *);
94 static void lock_check(void);
95 static Obj_Entry *obj_from_addr(const void *);
96 static void objlist_call_fini(Objlist *);
97 static void objlist_call_init(Objlist *);
98 static void objlist_clear(Objlist *);
99 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
100 static void objlist_init(Objlist *);
101 static void objlist_push_head(Objlist *, Obj_Entry *);
102 static void objlist_push_tail(Objlist *, Obj_Entry *);
103 static void objlist_remove(Objlist *, Obj_Entry *);
104 static void objlist_remove_unref(Objlist *);
105 static int relocate_objects(Obj_Entry *, bool);
106 static void rtld_exit(void);
107 static char *search_library_path(const char *, const char *);
108 static void set_program_var(const char *, const void *);
109 static const Elf_Sym *symlook_default(const char *, unsigned long hash,
110 const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt);
111 static const Elf_Sym *symlook_list(const char *, unsigned long,
112 Objlist *, const Obj_Entry **, bool in_plt, DoneList *);
113 static void trace_loaded_objects(Obj_Entry *obj);
114 static void unload_object(Obj_Entry *);
115 static void unref_dag(Obj_Entry *);
117 void r_debug_state(struct r_debug*, struct link_map*);
118 void xprintf(const char *, ...);
123 static char *error_message; /* Message for dlerror(), or NULL */
124 struct r_debug r_debug; /* for GDB; */
125 static bool trust; /* False for setuid and setgid programs */
126 static char *ld_bind_now; /* Environment variable for immediate binding */
127 static char *ld_debug; /* Environment variable for debugging */
128 static char *ld_library_path; /* Environment variable for search path */
129 static char *ld_preload; /* Environment variable for libraries to
131 static char *ld_tracing; /* Called from ldd to print libs */
132 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
133 static Obj_Entry **obj_tail; /* Link field of last object in list */
134 static Obj_Entry *obj_main; /* The main program shared object */
135 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
136 static unsigned int obj_count; /* Number of objects in obj_list */
138 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
139 STAILQ_HEAD_INITIALIZER(list_global);
140 static Objlist list_main = /* Objects loaded at program startup */
141 STAILQ_HEAD_INITIALIZER(list_main);
142 static Objlist list_fini = /* Objects needing fini() calls */
143 STAILQ_HEAD_INITIALIZER(list_fini);
145 static LockInfo lockinfo;
147 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
149 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
151 extern Elf_Dyn _DYNAMIC;
152 #pragma weak _DYNAMIC
155 * These are the functions the dynamic linker exports to application
156 * programs. They are the only symbols the dynamic linker is willing
157 * to export from itself.
159 static func_ptr_type exports[] = {
160 (func_ptr_type) &_rtld_error,
161 (func_ptr_type) &dlclose,
162 (func_ptr_type) &dlerror,
163 (func_ptr_type) &dlopen,
164 (func_ptr_type) &dlsym,
165 (func_ptr_type) &dladdr,
166 (func_ptr_type) &dllockinit,
171 * Global declarations normally provided by crt1. The dynamic linker is
172 * not built with crt1, so we have to provide them ourselves.
178 * Fill in a DoneList with an allocation large enough to hold all of
179 * the currently-loaded objects. Keep this as a macro since it calls
180 * alloca and we want that to occur within the scope of the caller.
182 #define donelist_init(dlp) \
183 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
184 assert((dlp)->objs != NULL), \
185 (dlp)->num_alloc = obj_count, \
191 lockinfo.rlock_acquire(lockinfo.thelock);
192 atomic_incr_int(&lockinfo.rcount);
199 lockinfo.wlock_acquire(lockinfo.thelock);
200 atomic_incr_int(&lockinfo.wcount);
207 atomic_decr_int(&lockinfo.rcount);
208 lockinfo.rlock_release(lockinfo.thelock);
214 atomic_decr_int(&lockinfo.wcount);
215 lockinfo.wlock_release(lockinfo.thelock);
219 * Main entry point for dynamic linking. The first argument is the
220 * stack pointer. The stack is expected to be laid out as described
221 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
222 * Specifically, the stack pointer points to a word containing
223 * ARGC. Following that in the stack is a null-terminated sequence
224 * of pointers to argument strings. Then comes a null-terminated
225 * sequence of pointers to environment strings. Finally, there is a
226 * sequence of "auxiliary vector" entries.
228 * The second argument points to a place to store the dynamic linker's
229 * exit procedure pointer and the third to a place to store the main
232 * The return value is the main program's entry point.
235 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
237 Elf_Auxinfo *aux_info[AT_COUNT];
246 Obj_Entry **preload_tail;
250 * On entry, the dynamic linker itself has not been relocated yet.
251 * Be very careful not to reference any global data until after
252 * init_rtld has returned. It is OK to reference file-scope statics
253 * and string constants, and to call static and global functions.
256 /* Find the auxiliary vector on the stack. */
259 sp += argc + 1; /* Skip over arguments and NULL terminator */
261 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
263 aux = (Elf_Auxinfo *) sp;
265 /* Digest the auxiliary vector. */
266 for (i = 0; i < AT_COUNT; i++)
268 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
269 if (auxp->a_type < AT_COUNT)
270 aux_info[auxp->a_type] = auxp;
273 /* Initialize and relocate ourselves. */
274 assert(aux_info[AT_BASE] != NULL);
275 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
277 __progname = obj_rtld.path;
278 argv0 = argv[0] != NULL ? argv[0] : "(null)";
281 trust = geteuid() == getuid() && getegid() == getgid();
283 ld_bind_now = getenv("LD_BIND_NOW");
285 ld_debug = getenv("LD_DEBUG");
286 ld_library_path = getenv("LD_LIBRARY_PATH");
287 ld_preload = getenv("LD_PRELOAD");
289 ld_tracing = getenv("LD_TRACE_LOADED_OBJECTS");
291 if (ld_debug != NULL && *ld_debug != '\0')
293 dbg("%s is initialized, base address = %p", __progname,
294 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
295 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
296 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
299 * Load the main program, or process its program header if it is
302 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
303 int fd = aux_info[AT_EXECFD]->a_un.a_val;
304 dbg("loading main program");
305 obj_main = map_object(fd, argv0, NULL);
307 if (obj_main == NULL)
309 } else { /* Main program already loaded. */
310 const Elf_Phdr *phdr;
314 dbg("processing main program's program header");
315 assert(aux_info[AT_PHDR] != NULL);
316 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
317 assert(aux_info[AT_PHNUM] != NULL);
318 phnum = aux_info[AT_PHNUM]->a_un.a_val;
319 assert(aux_info[AT_PHENT] != NULL);
320 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
321 assert(aux_info[AT_ENTRY] != NULL);
322 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
323 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
327 obj_main->path = xstrdup(argv0);
328 obj_main->mainprog = true;
331 * Get the actual dynamic linker pathname from the executable if
332 * possible. (It should always be possible.) That ensures that
333 * gdb will find the right dynamic linker even if a non-standard
336 if (obj_main->interp != NULL &&
337 strcmp(obj_main->interp, obj_rtld.path) != 0) {
339 obj_rtld.path = xstrdup(obj_main->interp);
342 digest_dynamic(obj_main);
344 linkmap_add(obj_main);
345 linkmap_add(&obj_rtld);
347 /* Link the main program into the list of objects. */
348 *obj_tail = obj_main;
349 obj_tail = &obj_main->next;
351 obj_main->refcount++;
352 /* Make sure we don't call the main program's init and fini functions. */
353 obj_main->init = obj_main->fini = NULL;
355 /* Initialize a fake symbol for resolving undefined weak references. */
356 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
357 sym_zero.st_shndx = SHN_ABS;
359 dbg("loading LD_PRELOAD libraries");
360 if (load_preload_objects() == -1)
362 preload_tail = obj_tail;
364 dbg("loading needed objects");
365 if (load_needed_objects(obj_main) == -1)
368 /* Make a list of all objects loaded at startup. */
369 for (obj = obj_list; obj != NULL; obj = obj->next)
370 objlist_push_tail(&list_main, obj);
372 if (ld_tracing) { /* We're done */
373 trace_loaded_objects(obj_main);
377 if (relocate_objects(obj_main,
378 ld_bind_now != NULL && *ld_bind_now != '\0') == -1)
381 dbg("doing copy relocations");
382 if (do_copy_relocations(obj_main) == -1)
385 dbg("initializing key program variables");
386 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
387 set_program_var("environ", env);
389 dbg("initializing thread locks");
390 lockdflt_init(&lockinfo);
391 lockinfo.thelock = lockinfo.lock_create(lockinfo.context);
393 /* Make a list of init functions to call. */
394 objlist_init(&initlist);
395 initlist_add_objects(obj_list, preload_tail, &initlist);
397 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
399 objlist_call_init(&initlist);
401 objlist_clear(&initlist);
404 dbg("transferring control to program entry point = %p", obj_main->entry);
406 /* Return the exit procedure and the program entry point. */
407 *exit_proc = rtld_exit;
409 return (func_ptr_type) obj_main->entry;
413 _rtld_bind(Obj_Entry *obj, Elf_Word reloff)
417 const Obj_Entry *defobj;
423 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
425 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
427 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
428 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true);
432 target = (Elf_Addr)(defobj->relocbase + def->st_value);
434 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
435 defobj->strtab + def->st_name, basename(obj->path),
436 (void *)target, basename(defobj->path));
438 reloc_jmpslot(where, target);
444 * Error reporting function. Use it like printf. If formats the message
445 * into a buffer, and sets things up so that the next call to dlerror()
446 * will return the message.
449 _rtld_error(const char *fmt, ...)
451 static char buf[512];
455 vsnprintf(buf, sizeof buf, fmt, ap);
461 basename(const char *name)
463 const char *p = strrchr(name, '/');
464 return p != NULL ? p + 1 : name;
470 const char *msg = dlerror();
478 * Process a shared object's DYNAMIC section, and save the important
479 * information in its Obj_Entry structure.
482 digest_dynamic(Obj_Entry *obj)
485 Needed_Entry **needed_tail = &obj->needed;
486 const Elf_Dyn *dyn_rpath = NULL;
487 int plttype = DT_REL;
489 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
490 switch (dynp->d_tag) {
493 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
497 obj->relsize = dynp->d_un.d_val;
501 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
505 obj->pltrel = (const Elf_Rel *)
506 (obj->relocbase + dynp->d_un.d_ptr);
510 obj->pltrelsize = dynp->d_un.d_val;
514 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
518 obj->relasize = dynp->d_un.d_val;
522 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
526 plttype = dynp->d_un.d_val;
527 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
531 obj->symtab = (const Elf_Sym *)
532 (obj->relocbase + dynp->d_un.d_ptr);
536 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
540 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
544 obj->strsize = dynp->d_un.d_val;
549 const Elf_Addr *hashtab = (const Elf_Addr *)
550 (obj->relocbase + dynp->d_un.d_ptr);
551 obj->nbuckets = hashtab[0];
552 obj->nchains = hashtab[1];
553 obj->buckets = hashtab + 2;
554 obj->chains = obj->buckets + obj->nbuckets;
560 Needed_Entry *nep = NEW(Needed_Entry);
561 nep->name = dynp->d_un.d_val;
566 needed_tail = &nep->next;
571 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
579 obj->symbolic = true;
584 * We have to wait until later to process this, because we
585 * might not have gotten the address of the string table yet.
591 /* Not used by the dynamic linker. */
595 obj->init = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr);
599 obj->fini = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr);
603 /* XXX - not implemented yet */
604 dbg("Filling in DT_DEBUG entry");
605 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
609 dbg("Ignoring d_tag %d = %#x", dynp->d_tag, dynp->d_tag);
616 if (plttype == DT_RELA) {
617 obj->pltrela = (const Elf_Rela *) obj->pltrel;
619 obj->pltrelasize = obj->pltrelsize;
623 if (dyn_rpath != NULL)
624 obj->rpath = obj->strtab + dyn_rpath->d_un.d_val;
628 * Process a shared object's program header. This is used only for the
629 * main program, when the kernel has already loaded the main program
630 * into memory before calling the dynamic linker. It creates and
631 * returns an Obj_Entry structure.
634 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
637 const Elf_Phdr *phlimit = phdr + phnum;
642 for (ph = phdr; ph < phlimit; ph++) {
643 switch (ph->p_type) {
646 if ((const Elf_Phdr *)ph->p_vaddr != phdr) {
647 _rtld_error("%s: invalid PT_PHDR", path);
650 obj->phdr = (const Elf_Phdr *) ph->p_vaddr;
651 obj->phsize = ph->p_memsz;
655 obj->interp = (const char *) ph->p_vaddr;
660 _rtld_error("%s: too many PT_LOAD segments", path);
663 if (nsegs == 0) { /* First load segment */
664 obj->vaddrbase = trunc_page(ph->p_vaddr);
665 obj->mapbase = (caddr_t) obj->vaddrbase;
666 obj->relocbase = obj->mapbase - obj->vaddrbase;
667 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
669 } else { /* Last load segment */
670 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
677 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr;
682 _rtld_error("%s: too few PT_LOAD segments", path);
691 dlcheck(void *handle)
695 for (obj = obj_list; obj != NULL; obj = obj->next)
696 if (obj == (Obj_Entry *) handle)
699 if (obj == NULL || obj->dl_refcount == 0) {
700 _rtld_error("Invalid shared object handle %p", handle);
707 * If the given object is already in the donelist, return true. Otherwise
708 * add the object to the list and return false.
711 donelist_check(DoneList *dlp, const Obj_Entry *obj)
715 for (i = 0; i < dlp->num_used; i++)
716 if (dlp->objs[i] == obj)
719 * Our donelist allocation should always be sufficient. But if
720 * our threads locking isn't working properly, more shared objects
721 * could have been loaded since we allocated the list. That should
722 * never happen, but we'll handle it properly just in case it does.
724 if (dlp->num_used < dlp->num_alloc)
725 dlp->objs[dlp->num_used++] = obj;
730 * Hash function for symbol table lookup. Don't even think about changing
731 * this. It is specified by the System V ABI.
734 elf_hash(const char *name)
736 const unsigned char *p = (const unsigned char *) name;
742 if ((g = h & 0xf0000000) != 0)
750 * Find the library with the given name, and return its full pathname.
751 * The returned string is dynamically allocated. Generates an error
752 * message and returns NULL if the library cannot be found.
754 * If the second argument is non-NULL, then it refers to an already-
755 * loaded shared object, whose library search path will be searched.
757 * The search order is:
758 * rpath in the referencing file
764 find_library(const char *name, const Obj_Entry *refobj)
768 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
769 if (name[0] != '/' && !trust) {
770 _rtld_error("Absolute pathname required for shared object \"%s\"",
774 return xstrdup(name);
777 dbg(" Searching for \"%s\"", name);
779 if ((refobj != NULL &&
780 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
781 (pathname = search_library_path(name, ld_library_path)) != NULL ||
782 (pathname = search_library_path(name, gethints())) != NULL ||
783 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
786 _rtld_error("Shared object \"%s\" not found", name);
791 * Given a symbol number in a referencing object, find the corresponding
792 * definition of the symbol. Returns a pointer to the symbol, or NULL if
793 * no definition was found. Returns a pointer to the Obj_Entry of the
794 * defining object via the reference parameter DEFOBJ_OUT.
797 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
798 const Obj_Entry **defobj_out, bool in_plt)
802 const Obj_Entry *defobj;
806 ref = refobj->symtab + symnum;
807 name = refobj->strtab + ref->st_name;
808 hash = elf_hash(name);
811 def = symlook_default(name, hash, refobj, &defobj, in_plt);
814 * If we found no definition and the reference is weak, treat the
815 * symbol as having the value zero.
817 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
823 *defobj_out = defobj;
825 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
830 * Return the search path from the ldconfig hints file, reading it if
831 * necessary. Returns NULL if there are problems with the hints file,
832 * or if the search path there is empty.
841 struct elfhints_hdr hdr;
844 /* Keep from trying again in case the hints file is bad. */
847 if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1)
849 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
850 hdr.magic != ELFHINTS_MAGIC ||
855 p = xmalloc(hdr.dirlistlen + 1);
856 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
857 read(fd, p, hdr.dirlistlen + 1) != hdr.dirlistlen + 1) {
865 return hints[0] != '\0' ? hints : NULL;
869 init_dag(Obj_Entry *root)
873 donelist_init(&donelist);
874 init_dag1(root, root, &donelist);
878 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
880 const Needed_Entry *needed;
882 if (donelist_check(dlp, obj))
884 objlist_push_tail(&obj->dldags, root);
885 objlist_push_tail(&root->dagmembers, obj);
886 for (needed = obj->needed; needed != NULL; needed = needed->next)
887 if (needed->obj != NULL)
888 init_dag1(root, needed->obj, dlp);
892 * Initialize the dynamic linker. The argument is the address at which
893 * the dynamic linker has been mapped into memory. The primary task of
894 * this function is to relocate the dynamic linker.
897 init_rtld(caddr_t mapbase)
900 * Conjure up an Obj_Entry structure for the dynamic linker.
902 * The "path" member is supposed to be dynamically-allocated, but we
903 * aren't yet initialized sufficiently to do that. Below we will
904 * replace the static version with a dynamically-allocated copy.
906 obj_rtld.path = PATH_RTLD;
907 obj_rtld.rtld = true;
908 obj_rtld.mapbase = mapbase;
910 obj_rtld.relocbase = mapbase;
912 if (&_DYNAMIC != 0) {
913 obj_rtld.dynamic = rtld_dynamic(&obj_rtld);
914 digest_dynamic(&obj_rtld);
915 assert(obj_rtld.needed == NULL);
916 assert(!obj_rtld.textrel);
919 * Temporarily put the dynamic linker entry into the object list, so
920 * that symbols can be found.
922 obj_list = &obj_rtld;
923 obj_tail = &obj_rtld.next;
926 relocate_objects(&obj_rtld, true);
929 /* Make the object list empty again. */
931 obj_tail = &obj_list;
934 /* Replace the path with a dynamically allocated copy. */
935 obj_rtld.path = xstrdup(obj_rtld.path);
937 r_debug.r_brk = r_debug_state;
938 r_debug.r_state = RT_CONSISTENT;
942 * Add the init functions from a needed object list (and its recursive
943 * needed objects) to "list". This is not used directly; it is a helper
944 * function for initlist_add_objects(). The write lock must be held
945 * when this function is called.
948 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
950 /* Recursively process the successor needed objects. */
951 if (needed->next != NULL)
952 initlist_add_neededs(needed->next, list);
954 /* Process the current needed object. */
955 if (needed->obj != NULL)
956 initlist_add_objects(needed->obj, &needed->obj->next, list);
960 * Scan all of the DAGs rooted in the range of objects from "obj" to
961 * "tail" and add their init functions to "list". This recurses over
962 * the DAGs and ensure the proper init ordering such that each object's
963 * needed libraries are initialized before the object itself. At the
964 * same time, this function adds the objects to the global finalization
965 * list "list_fini" in the opposite order. The write lock must be
966 * held when this function is called.
969 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
973 obj->init_done = true;
975 /* Recursively process the successor objects. */
976 if (&obj->next != tail)
977 initlist_add_objects(obj->next, tail, list);
979 /* Recursively process the needed objects. */
980 if (obj->needed != NULL)
981 initlist_add_neededs(obj->needed, list);
983 /* Add the object to the init list. */
984 if (obj->init != NULL)
985 objlist_push_tail(list, obj);
987 /* Add the object to the global fini list in the reverse order. */
988 if (obj->fini != NULL)
989 objlist_push_head(&list_fini, obj);
993 is_exported(const Elf_Sym *def)
996 const func_ptr_type *p;
998 value = (func_ptr_type)(obj_rtld.relocbase + def->st_value);
999 for (p = exports; *p != NULL; p++)
1006 * Given a shared object, traverse its list of needed objects, and load
1007 * each of them. Returns 0 on success. Generates an error message and
1008 * returns -1 on failure.
1011 load_needed_objects(Obj_Entry *first)
1015 for (obj = first; obj != NULL; obj = obj->next) {
1016 Needed_Entry *needed;
1018 for (needed = obj->needed; needed != NULL; needed = needed->next) {
1019 const char *name = obj->strtab + needed->name;
1020 char *path = find_library(name, obj);
1023 if (path == NULL && !ld_tracing)
1027 needed->obj = load_object(path);
1028 if (needed->obj == NULL && !ld_tracing)
1029 return -1; /* XXX - cleanup */
1038 load_preload_objects(void)
1040 char *p = ld_preload;
1041 static const char delim[] = " \t:;";
1046 p += strspn(p, delim);
1047 while (*p != '\0') {
1048 size_t len = strcspn(p, delim);
1054 if ((path = find_library(p, NULL)) == NULL)
1056 if (load_object(path) == NULL)
1057 return -1; /* XXX - cleanup */
1060 p += strspn(p, delim);
1066 * Load a shared object into memory, if it is not already loaded. The
1067 * argument must be a string allocated on the heap. This function assumes
1068 * responsibility for freeing it when necessary.
1070 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1074 load_object(char *path)
1080 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1081 if (strcmp(obj->path, path) == 0)
1085 * If we didn't find a match by pathname, open the file and check
1086 * again by device and inode. This avoids false mismatches caused
1087 * by multiple links or ".." in pathnames.
1089 * To avoid a race, we open the file and use fstat() rather than
1093 if ((fd = open(path, O_RDONLY)) == -1) {
1094 _rtld_error("Cannot open \"%s\"", path);
1097 if (fstat(fd, &sb) == -1) {
1098 _rtld_error("Cannot fstat \"%s\"", path);
1102 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
1103 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) {
1110 if (obj == NULL) { /* First use of this object, so we must map it in */
1111 dbg("loading \"%s\"", path);
1112 obj = map_object(fd, path, &sb);
1120 digest_dynamic(obj);
1123 obj_tail = &obj->next;
1125 linkmap_add(obj); /* for GDB */
1127 dbg(" %p .. %p: %s", obj->mapbase,
1128 obj->mapbase + obj->mapsize - 1, obj->path);
1130 dbg(" WARNING: %s has impure text", obj->path);
1139 * Check for locking violations and die if one is found.
1146 rcount = lockinfo.rcount;
1147 wcount = lockinfo.wcount;
1148 assert(rcount >= 0);
1149 assert(wcount >= 0);
1150 if (wcount > 1 || (wcount != 0 && rcount != 0)) {
1151 _rtld_error("Application locking error: %d readers and %d writers"
1152 " in dynamic linker. See DLLOCKINIT(3) in manual pages.",
1159 obj_from_addr(const void *addr)
1161 unsigned long endhash;
1164 endhash = elf_hash(END_SYM);
1165 for (obj = obj_list; obj != NULL; obj = obj->next) {
1166 const Elf_Sym *endsym;
1168 if (addr < (void *) obj->mapbase)
1170 if ((endsym = symlook_obj(END_SYM, endhash, obj, true)) == NULL)
1171 continue; /* No "end" symbol?! */
1172 if (addr < (void *) (obj->relocbase + endsym->st_value))
1179 * Call the finalization functions for each of the objects in "list"
1180 * which are unreferenced. All of the objects are expected to have
1181 * non-NULL fini functions.
1184 objlist_call_fini(Objlist *list)
1188 STAILQ_FOREACH(elm, list, link) {
1189 if (elm->obj->refcount == 0) {
1190 dbg("calling fini function for %s", elm->obj->path);
1191 (*elm->obj->fini)();
1197 * Call the initialization functions for each of the objects in
1198 * "list". All of the objects are expected to have non-NULL init
1202 objlist_call_init(Objlist *list)
1206 STAILQ_FOREACH(elm, list, link) {
1207 dbg("calling init function for %s", elm->obj->path);
1208 (*elm->obj->init)();
1213 objlist_clear(Objlist *list)
1217 while (!STAILQ_EMPTY(list)) {
1218 elm = STAILQ_FIRST(list);
1219 STAILQ_REMOVE_HEAD(list, link);
1224 static Objlist_Entry *
1225 objlist_find(Objlist *list, const Obj_Entry *obj)
1229 STAILQ_FOREACH(elm, list, link)
1230 if (elm->obj == obj)
1236 objlist_init(Objlist *list)
1242 objlist_push_head(Objlist *list, Obj_Entry *obj)
1246 elm = NEW(Objlist_Entry);
1248 STAILQ_INSERT_HEAD(list, elm, link);
1252 objlist_push_tail(Objlist *list, Obj_Entry *obj)
1256 elm = NEW(Objlist_Entry);
1258 STAILQ_INSERT_TAIL(list, elm, link);
1262 objlist_remove(Objlist *list, Obj_Entry *obj)
1266 if ((elm = objlist_find(list, obj)) != NULL) {
1267 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1273 * Remove all of the unreferenced objects from "list".
1276 objlist_remove_unref(Objlist *list)
1281 STAILQ_INIT(&newlist);
1282 while (!STAILQ_EMPTY(list)) {
1283 elm = STAILQ_FIRST(list);
1284 STAILQ_REMOVE_HEAD(list, link);
1285 if (elm->obj->refcount == 0)
1288 STAILQ_INSERT_TAIL(&newlist, elm, link);
1294 * Relocate newly-loaded shared objects. The argument is a pointer to
1295 * the Obj_Entry for the first such object. All objects from the first
1296 * to the end of the list of objects are relocated. Returns 0 on success,
1300 relocate_objects(Obj_Entry *first, bool bind_now)
1304 for (obj = first; obj != NULL; obj = obj->next) {
1305 if (obj != &obj_rtld)
1306 dbg("relocating \"%s\"", obj->path);
1307 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
1308 obj->symtab == NULL || obj->strtab == NULL) {
1309 _rtld_error("%s: Shared object has no run-time symbol table",
1315 /* There are relocations to the write-protected text segment. */
1316 if (mprotect(obj->mapbase, obj->textsize,
1317 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
1318 _rtld_error("%s: Cannot write-enable text segment: %s",
1319 obj->path, strerror(errno));
1324 /* Process the non-PLT relocations. */
1325 if (reloc_non_plt(obj, &obj_rtld))
1328 if (obj->textrel) { /* Re-protected the text segment. */
1329 if (mprotect(obj->mapbase, obj->textsize,
1330 PROT_READ|PROT_EXEC) == -1) {
1331 _rtld_error("%s: Cannot write-protect text segment: %s",
1332 obj->path, strerror(errno));
1337 /* Process the PLT relocations. */
1338 if (reloc_plt(obj) == -1)
1340 /* Relocate the jump slots if we are doing immediate binding. */
1342 if (reloc_jmpslots(obj) == -1)
1347 * Set up the magic number and version in the Obj_Entry. These
1348 * were checked in the crt1.o from the original ElfKit, so we
1349 * set them for backward compatibility.
1351 obj->magic = RTLD_MAGIC;
1352 obj->version = RTLD_VERSION;
1354 /* Set the special PLT or GOT entries. */
1362 * Cleanup procedure. It will be called (by the atexit mechanism) just
1363 * before the process exits.
1372 /* Clear all the reference counts so the fini functions will be called. */
1373 for (obj = obj_list; obj != NULL; obj = obj->next)
1376 objlist_call_fini(&list_fini);
1377 /* No need to remove the items from the list, since we are exiting. */
1381 search_library_path(const char *name, const char *path)
1383 size_t namelen = strlen(name);
1384 const char *p = path;
1389 p += strspn(p, ":;");
1390 while (*p != '\0') {
1391 size_t len = strcspn(p, ":;");
1393 if (*p == '/' || trust) {
1395 const char *dir = p;
1396 size_t dirlen = len;
1398 pathname = xmalloc(dirlen + 1 + namelen + 1);
1399 strncpy(pathname, dir, dirlen);
1400 pathname[dirlen] = '/';
1401 strcpy(pathname + dirlen + 1, name);
1403 dbg(" Trying \"%s\"", pathname);
1404 if (access(pathname, F_OK) == 0) /* We found it */
1410 p += strspn(p, ":;");
1417 dlclose(void *handle)
1422 root = dlcheck(handle);
1428 /* Unreference the object and its dependencies. */
1429 root->dl_refcount--;
1432 if (root->refcount == 0) {
1434 * The object is no longer referenced, so we must unload it.
1435 * First, call the fini functions with no locks held.
1438 objlist_call_fini(&list_fini);
1440 objlist_remove_unref(&list_fini);
1442 /* Finish cleaning up the newly-unreferenced objects. */
1443 GDB_STATE(RT_DELETE,&root->linkmap);
1444 unload_object(root);
1445 GDB_STATE(RT_CONSISTENT,NULL);
1454 char *msg = error_message;
1455 error_message = NULL;
1460 * This function is deprecated and has no effect.
1463 dllockinit(void *context,
1464 void *(*lock_create)(void *context),
1465 void (*rlock_acquire)(void *lock),
1466 void (*wlock_acquire)(void *lock),
1467 void (*lock_release)(void *lock),
1468 void (*lock_destroy)(void *lock),
1469 void (*context_destroy)(void *context))
1471 static void *cur_context;
1472 static void (*cur_context_destroy)(void *);
1474 /* Just destroy the context from the previous call, if necessary. */
1475 if (cur_context_destroy != NULL)
1476 cur_context_destroy(cur_context);
1477 cur_context = context;
1478 cur_context_destroy = context_destroy;
1482 dlopen(const char *name, int mode)
1484 Obj_Entry **old_obj_tail;
1488 objlist_init(&initlist);
1491 GDB_STATE(RT_ADD,NULL);
1493 old_obj_tail = obj_tail;
1499 char *path = find_library(name, obj_main);
1501 obj = load_object(path);
1506 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
1507 objlist_push_tail(&list_global, obj);
1508 mode &= RTLD_MODEMASK;
1509 if (*old_obj_tail != NULL) { /* We loaded something new. */
1510 assert(*old_obj_tail == obj);
1512 if (load_needed_objects(obj) == -1 ||
1513 (init_dag(obj), relocate_objects(obj, mode == RTLD_NOW)) == -1) {
1516 if (obj->refcount == 0)
1520 /* Make list of init functions to call. */
1521 initlist_add_objects(obj, &obj->next, &initlist);
1526 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
1528 /* Call the init functions with no locks held. */
1530 objlist_call_init(&initlist);
1532 objlist_clear(&initlist);
1538 dlsym(void *handle, const char *name)
1540 const Obj_Entry *obj;
1543 const Obj_Entry *defobj;
1545 hash = elf_hash(name);
1550 if (handle == NULL || handle == RTLD_NEXT || handle == RTLD_DEFAULT) {
1553 retaddr = __builtin_return_address(0); /* __GNUC__ only */
1554 if ((obj = obj_from_addr(retaddr)) == NULL) {
1555 _rtld_error("Cannot determine caller's shared object");
1559 if (handle == NULL) { /* Just the caller's shared object. */
1560 def = symlook_obj(name, hash, obj, true);
1562 } else if (handle == RTLD_NEXT) { /* Objects after caller's */
1563 while ((obj = obj->next) != NULL) {
1564 if ((def = symlook_obj(name, hash, obj, true)) != NULL) {
1570 assert(handle == RTLD_DEFAULT);
1571 def = symlook_default(name, hash, obj, &defobj, true);
1574 if ((obj = dlcheck(handle)) == NULL) {
1579 if (obj->mainprog) {
1582 /* Search main program and all libraries loaded by it. */
1583 donelist_init(&donelist);
1584 def = symlook_list(name, hash, &list_main, &defobj, true,
1588 * XXX - This isn't correct. The search should include the whole
1589 * DAG rooted at the given object.
1591 def = symlook_obj(name, hash, obj, true);
1598 return defobj->relocbase + def->st_value;
1601 _rtld_error("Undefined symbol \"%s\"", name);
1607 dladdr(const void *addr, Dl_info *info)
1609 const Obj_Entry *obj;
1612 unsigned long symoffset;
1615 obj = obj_from_addr(addr);
1617 _rtld_error("No shared object contains address");
1621 info->dli_fname = obj->path;
1622 info->dli_fbase = obj->mapbase;
1623 info->dli_saddr = (void *)0;
1624 info->dli_sname = NULL;
1627 * Walk the symbol list looking for the symbol whose address is
1628 * closest to the address sent in.
1630 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
1631 def = obj->symtab + symoffset;
1634 * For skip the symbol if st_shndx is either SHN_UNDEF or
1637 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
1641 * If the symbol is greater than the specified address, or if it
1642 * is further away from addr than the current nearest symbol,
1645 symbol_addr = obj->relocbase + def->st_value;
1646 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
1649 /* Update our idea of the nearest symbol. */
1650 info->dli_sname = obj->strtab + def->st_name;
1651 info->dli_saddr = symbol_addr;
1654 if (info->dli_saddr == addr)
1662 linkmap_add(Obj_Entry *obj)
1664 struct link_map *l = &obj->linkmap;
1665 struct link_map *prev;
1667 obj->linkmap.l_name = obj->path;
1668 obj->linkmap.l_addr = obj->mapbase;
1669 obj->linkmap.l_ld = obj->dynamic;
1671 /* GDB needs load offset on MIPS to use the symbols */
1672 obj->linkmap.l_offs = obj->relocbase;
1675 if (r_debug.r_map == NULL) {
1681 * Scan to the end of the list, but not past the entry for the
1682 * dynamic linker, which we want to keep at the very end.
1684 for (prev = r_debug.r_map;
1685 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
1686 prev = prev->l_next)
1689 /* Link in the new entry. */
1691 l->l_next = prev->l_next;
1692 if (l->l_next != NULL)
1693 l->l_next->l_prev = l;
1698 linkmap_delete(Obj_Entry *obj)
1700 struct link_map *l = &obj->linkmap;
1702 if (l->l_prev == NULL) {
1703 if ((r_debug.r_map = l->l_next) != NULL)
1704 l->l_next->l_prev = NULL;
1708 if ((l->l_prev->l_next = l->l_next) != NULL)
1709 l->l_next->l_prev = l->l_prev;
1713 * Function for the debugger to set a breakpoint on to gain control.
1715 * The two parameters allow the debugger to easily find and determine
1716 * what the runtime loader is doing and to whom it is doing it.
1718 * When the loadhook trap is hit (r_debug_state, set at program
1719 * initialization), the arguments can be found on the stack:
1721 * +8 struct link_map *m
1722 * +4 struct r_debug *rd
1726 r_debug_state(struct r_debug* rd, struct link_map *m)
1731 * Set a pointer variable in the main program to the given value. This
1732 * is used to set key variables such as "environ" before any of the
1733 * init functions are called.
1736 set_program_var(const char *name, const void *value)
1738 const Obj_Entry *obj;
1741 hash = elf_hash(name);
1742 for (obj = obj_main; obj != NULL; obj = obj->next) {
1745 if ((def = symlook_obj(name, hash, obj, false)) != NULL) {
1748 addr = (const void **)(obj->relocbase + def->st_value);
1749 dbg("\"%s\": *%p <-- %p", name, addr, value);
1757 * Given a symbol name in a referencing object, find the corresponding
1758 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1759 * no definition was found. Returns a pointer to the Obj_Entry of the
1760 * defining object via the reference parameter DEFOBJ_OUT.
1762 static const Elf_Sym *
1763 symlook_default(const char *name, unsigned long hash,
1764 const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt)
1768 const Elf_Sym *symp;
1769 const Obj_Entry *obj;
1770 const Obj_Entry *defobj;
1771 const Objlist_Entry *elm;
1774 donelist_init(&donelist);
1776 /* Look first in the referencing object if linked symbolically. */
1777 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
1778 symp = symlook_obj(name, hash, refobj, in_plt);
1785 /* Search all objects loaded at program start up. */
1786 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
1787 symp = symlook_list(name, hash, &list_main, &obj, in_plt, &donelist);
1789 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
1795 /* Search all dlopened DAGs containing the referencing object. */
1796 STAILQ_FOREACH(elm, &refobj->dldags, link) {
1797 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
1799 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt,
1802 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
1808 /* Search all RTLD_GLOBAL objects. */
1809 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
1810 symp = symlook_list(name, hash, &list_global, &obj, in_plt, &donelist);
1812 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
1819 * Search the dynamic linker itself, and possibly resolve the
1820 * symbol from there. This is how the application links to
1821 * dynamic linker services such as dlopen. Only the values listed
1822 * in the "exports" array can be resolved from the dynamic linker.
1824 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
1825 symp = symlook_obj(name, hash, &obj_rtld, in_plt);
1826 if (symp != NULL && is_exported(symp)) {
1833 *defobj_out = defobj;
1837 static const Elf_Sym *
1838 symlook_list(const char *name, unsigned long hash, Objlist *objlist,
1839 const Obj_Entry **defobj_out, bool in_plt, DoneList *dlp)
1841 const Elf_Sym *symp;
1843 const Obj_Entry *defobj;
1844 const Objlist_Entry *elm;
1848 STAILQ_FOREACH(elm, objlist, link) {
1849 if (donelist_check(dlp, elm->obj))
1851 if ((symp = symlook_obj(name, hash, elm->obj, in_plt)) != NULL) {
1852 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
1855 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
1861 *defobj_out = defobj;
1866 * Search the symbol table of a single shared object for a symbol of
1867 * the given name. Returns a pointer to the symbol, or NULL if no
1868 * definition was found.
1870 * The symbol's hash value is passed in for efficiency reasons; that
1871 * eliminates many recomputations of the hash value.
1874 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj,
1877 if (obj->buckets != NULL) {
1878 unsigned long symnum = obj->buckets[hash % obj->nbuckets];
1880 while (symnum != STN_UNDEF) {
1881 const Elf_Sym *symp;
1884 if (symnum >= obj->nchains)
1885 return NULL; /* Bad object */
1886 symp = obj->symtab + symnum;
1887 strp = obj->strtab + symp->st_name;
1889 if (strcmp(name, strp) == 0)
1890 return symp->st_shndx != SHN_UNDEF ||
1891 (!in_plt && symp->st_value != 0 &&
1892 ELF_ST_TYPE(symp->st_info) == STT_FUNC) ? symp : NULL;
1894 symnum = obj->chains[symnum];
1901 trace_loaded_objects(Obj_Entry *obj)
1903 char *fmt1, *fmt2, *fmt, *main_local;
1906 if ((main_local = getenv("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
1909 if ((fmt1 = getenv("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
1910 fmt1 = "\t%o => %p (%x)\n";
1912 if ((fmt2 = getenv("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
1913 fmt2 = "\t%o (%x)\n";
1915 for (; obj; obj = obj->next) {
1916 Needed_Entry *needed;
1920 for (needed = obj->needed; needed; needed = needed->next) {
1921 if (needed->obj != NULL) {
1922 if (needed->obj->traced)
1924 needed->obj->traced = true;
1925 path = needed->obj->path;
1929 name = (char *)obj->strtab + needed->name;
1930 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
1932 fmt = is_lib ? fmt1 : fmt2;
1933 while ((c = *fmt++) != '\0') {
1959 printf("%s", main_local);
1962 printf("%s", obj_main->path);
1969 printf("%d", sodp->sod_major);
1972 printf("%d", sodp->sod_minor);
1979 printf("%p", needed->obj ? needed->obj->mapbase : 0);
1991 * Unload a dlopened object and its dependencies from memory and from
1992 * our data structures. It is assumed that the DAG rooted in the
1993 * object has already been unreferenced, and that the object has a
1994 * reference count of 0.
1997 unload_object(Obj_Entry *root)
2003 assert(root->refcount == 0);
2005 /* Remove the DAG from all objects' DAG lists. */
2006 STAILQ_FOREACH(elm, &root->dagmembers , link)
2007 objlist_remove(&elm->obj->dldags, root);
2009 /* Remove the DAG from the RTLD_GLOBAL list. */
2010 objlist_remove(&list_global, root);
2012 /* Unmap all objects that are no longer referenced. */
2013 linkp = &obj_list->next;
2014 while ((obj = *linkp) != NULL) {
2015 if (obj->refcount == 0) {
2016 dbg("unloading \"%s\"", obj->path);
2017 munmap(obj->mapbase, obj->mapsize);
2018 linkmap_delete(obj);
2029 unref_dag(Obj_Entry *root)
2031 const Needed_Entry *needed;
2033 assert(root->refcount != 0);
2035 if (root->refcount == 0)
2036 for (needed = root->needed; needed != NULL; needed = needed->next)
2037 if (needed->obj != NULL)
2038 unref_dag(needed->obj);
2042 * Non-mallocing printf, for use by malloc itself.
2043 * XXX - This doesn't belong in this module.
2046 xprintf(const char *fmt, ...)
2052 vsprintf(buf, fmt, ap);
2053 (void)write(1, buf, strlen(buf));