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 void errmsg_restore(char *);
81 static char *errmsg_save(void);
82 static char *find_library(const char *, const Obj_Entry *);
83 static const char *gethints(void);
84 static void init_dag(Obj_Entry *);
85 static void init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *);
86 static void init_rtld(caddr_t);
87 static void initlist_add_neededs(Needed_Entry *needed, Objlist *list);
88 static void initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail,
90 static bool is_exported(const Elf_Sym *);
91 static void linkmap_add(Obj_Entry *);
92 static void linkmap_delete(Obj_Entry *);
93 static int load_needed_objects(Obj_Entry *);
94 static int load_preload_objects(void);
95 static Obj_Entry *load_object(char *);
96 static void lock_check(void);
97 static Obj_Entry *obj_from_addr(const void *);
98 static void objlist_call_fini(Objlist *);
99 static void objlist_call_init(Objlist *);
100 static void objlist_clear(Objlist *);
101 static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
102 static void objlist_init(Objlist *);
103 static void objlist_push_head(Objlist *, Obj_Entry *);
104 static void objlist_push_tail(Objlist *, Obj_Entry *);
105 static void objlist_remove(Objlist *, Obj_Entry *);
106 static void objlist_remove_unref(Objlist *);
107 static int relocate_objects(Obj_Entry *, bool);
108 static void rtld_exit(void);
109 static char *search_library_path(const char *, const char *);
110 static void set_program_var(const char *, const void *);
111 static const Elf_Sym *symlook_default(const char *, unsigned long hash,
112 const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt);
113 static const Elf_Sym *symlook_list(const char *, unsigned long,
114 Objlist *, const Obj_Entry **, bool in_plt, DoneList *);
115 static void trace_loaded_objects(Obj_Entry *obj);
116 static void unload_object(Obj_Entry *);
117 static void unref_dag(Obj_Entry *);
119 void r_debug_state(struct r_debug*, struct link_map*);
120 void xprintf(const char *, ...);
125 static char *error_message; /* Message for dlerror(), or NULL */
126 struct r_debug r_debug; /* for GDB; */
127 static bool trust; /* False for setuid and setgid programs */
128 static char *ld_bind_now; /* Environment variable for immediate binding */
129 static char *ld_debug; /* Environment variable for debugging */
130 static char *ld_library_path; /* Environment variable for search path */
131 static char *ld_preload; /* Environment variable for libraries to
133 static char *ld_tracing; /* Called from ldd to print libs */
134 static Obj_Entry *obj_list; /* Head of linked list of shared objects */
135 static Obj_Entry **obj_tail; /* Link field of last object in list */
136 static Obj_Entry *obj_main; /* The main program shared object */
137 static Obj_Entry obj_rtld; /* The dynamic linker shared object */
138 static unsigned int obj_count; /* Number of objects in obj_list */
140 static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */
141 STAILQ_HEAD_INITIALIZER(list_global);
142 static Objlist list_main = /* Objects loaded at program startup */
143 STAILQ_HEAD_INITIALIZER(list_main);
144 static Objlist list_fini = /* Objects needing fini() calls */
145 STAILQ_HEAD_INITIALIZER(list_fini);
147 static LockInfo lockinfo;
149 static Elf_Sym sym_zero; /* For resolving undefined weak refs. */
151 #define GDB_STATE(s,m) r_debug.r_state = s; r_debug_state(&r_debug,m);
153 extern Elf_Dyn _DYNAMIC;
154 #pragma weak _DYNAMIC
157 * These are the functions the dynamic linker exports to application
158 * programs. They are the only symbols the dynamic linker is willing
159 * to export from itself.
161 static func_ptr_type exports[] = {
162 (func_ptr_type) &_rtld_error,
163 (func_ptr_type) &dlclose,
164 (func_ptr_type) &dlerror,
165 (func_ptr_type) &dlopen,
166 (func_ptr_type) &dlsym,
167 (func_ptr_type) &dladdr,
168 (func_ptr_type) &dllockinit,
173 * Global declarations normally provided by crt1. The dynamic linker is
174 * not built with crt1, so we have to provide them ourselves.
180 * Fill in a DoneList with an allocation large enough to hold all of
181 * the currently-loaded objects. Keep this as a macro since it calls
182 * alloca and we want that to occur within the scope of the caller.
184 #define donelist_init(dlp) \
185 ((dlp)->objs = alloca(obj_count * sizeof (dlp)->objs[0]), \
186 assert((dlp)->objs != NULL), \
187 (dlp)->num_alloc = obj_count, \
193 lockinfo.rlock_acquire(lockinfo.thelock);
194 atomic_incr_int(&lockinfo.rcount);
201 lockinfo.wlock_acquire(lockinfo.thelock);
202 atomic_incr_int(&lockinfo.wcount);
209 atomic_decr_int(&lockinfo.rcount);
210 lockinfo.rlock_release(lockinfo.thelock);
216 atomic_decr_int(&lockinfo.wcount);
217 lockinfo.wlock_release(lockinfo.thelock);
221 * Main entry point for dynamic linking. The first argument is the
222 * stack pointer. The stack is expected to be laid out as described
223 * in the SVR4 ABI specification, Intel 386 Processor Supplement.
224 * Specifically, the stack pointer points to a word containing
225 * ARGC. Following that in the stack is a null-terminated sequence
226 * of pointers to argument strings. Then comes a null-terminated
227 * sequence of pointers to environment strings. Finally, there is a
228 * sequence of "auxiliary vector" entries.
230 * The second argument points to a place to store the dynamic linker's
231 * exit procedure pointer and the third to a place to store the main
234 * The return value is the main program's entry point.
237 _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
239 Elf_Auxinfo *aux_info[AT_COUNT];
248 Obj_Entry **preload_tail;
252 * On entry, the dynamic linker itself has not been relocated yet.
253 * Be very careful not to reference any global data until after
254 * init_rtld has returned. It is OK to reference file-scope statics
255 * and string constants, and to call static and global functions.
258 /* Find the auxiliary vector on the stack. */
261 sp += argc + 1; /* Skip over arguments and NULL terminator */
263 while (*sp++ != 0) /* Skip over environment, and NULL terminator */
265 aux = (Elf_Auxinfo *) sp;
267 /* Digest the auxiliary vector. */
268 for (i = 0; i < AT_COUNT; i++)
270 for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
271 if (auxp->a_type < AT_COUNT)
272 aux_info[auxp->a_type] = auxp;
275 /* Initialize and relocate ourselves. */
276 assert(aux_info[AT_BASE] != NULL);
277 init_rtld((caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
279 __progname = obj_rtld.path;
280 argv0 = argv[0] != NULL ? argv[0] : "(null)";
283 trust = geteuid() == getuid() && getegid() == getgid();
285 ld_bind_now = getenv("LD_BIND_NOW");
287 ld_debug = getenv("LD_DEBUG");
288 ld_library_path = getenv("LD_LIBRARY_PATH");
289 ld_preload = getenv("LD_PRELOAD");
291 ld_tracing = getenv("LD_TRACE_LOADED_OBJECTS");
293 if (ld_debug != NULL && *ld_debug != '\0')
295 dbg("%s is initialized, base address = %p", __progname,
296 (caddr_t) aux_info[AT_BASE]->a_un.a_ptr);
297 dbg("RTLD dynamic = %p", obj_rtld.dynamic);
298 dbg("RTLD pltgot = %p", obj_rtld.pltgot);
301 * Load the main program, or process its program header if it is
304 if (aux_info[AT_EXECFD] != NULL) { /* Load the main program. */
305 int fd = aux_info[AT_EXECFD]->a_un.a_val;
306 dbg("loading main program");
307 obj_main = map_object(fd, argv0, NULL);
309 if (obj_main == NULL)
311 } else { /* Main program already loaded. */
312 const Elf_Phdr *phdr;
316 dbg("processing main program's program header");
317 assert(aux_info[AT_PHDR] != NULL);
318 phdr = (const Elf_Phdr *) aux_info[AT_PHDR]->a_un.a_ptr;
319 assert(aux_info[AT_PHNUM] != NULL);
320 phnum = aux_info[AT_PHNUM]->a_un.a_val;
321 assert(aux_info[AT_PHENT] != NULL);
322 assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr));
323 assert(aux_info[AT_ENTRY] != NULL);
324 entry = (caddr_t) aux_info[AT_ENTRY]->a_un.a_ptr;
325 if ((obj_main = digest_phdr(phdr, phnum, entry, argv0)) == NULL)
329 obj_main->path = xstrdup(argv0);
330 obj_main->mainprog = true;
333 * Get the actual dynamic linker pathname from the executable if
334 * possible. (It should always be possible.) That ensures that
335 * gdb will find the right dynamic linker even if a non-standard
338 if (obj_main->interp != NULL &&
339 strcmp(obj_main->interp, obj_rtld.path) != 0) {
341 obj_rtld.path = xstrdup(obj_main->interp);
344 digest_dynamic(obj_main);
346 linkmap_add(obj_main);
347 linkmap_add(&obj_rtld);
349 /* Link the main program into the list of objects. */
350 *obj_tail = obj_main;
351 obj_tail = &obj_main->next;
353 obj_main->refcount++;
354 /* Make sure we don't call the main program's init and fini functions. */
355 obj_main->init = obj_main->fini = NULL;
357 /* Initialize a fake symbol for resolving undefined weak references. */
358 sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
359 sym_zero.st_shndx = SHN_ABS;
361 dbg("loading LD_PRELOAD libraries");
362 if (load_preload_objects() == -1)
364 preload_tail = obj_tail;
366 dbg("loading needed objects");
367 if (load_needed_objects(obj_main) == -1)
370 /* Make a list of all objects loaded at startup. */
371 for (obj = obj_list; obj != NULL; obj = obj->next)
372 objlist_push_tail(&list_main, obj);
374 if (ld_tracing) { /* We're done */
375 trace_loaded_objects(obj_main);
379 if (relocate_objects(obj_main,
380 ld_bind_now != NULL && *ld_bind_now != '\0') == -1)
383 dbg("doing copy relocations");
384 if (do_copy_relocations(obj_main) == -1)
387 dbg("initializing key program variables");
388 set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : "");
389 set_program_var("environ", env);
391 dbg("initializing thread locks");
392 lockdflt_init(&lockinfo);
393 lockinfo.thelock = lockinfo.lock_create(lockinfo.context);
395 /* Make a list of init functions to call. */
396 objlist_init(&initlist);
397 initlist_add_objects(obj_list, preload_tail, &initlist);
399 r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */
401 objlist_call_init(&initlist);
403 objlist_clear(&initlist);
406 dbg("transferring control to program entry point = %p", obj_main->entry);
408 /* Return the exit procedure and the program entry point. */
409 *exit_proc = rtld_exit;
411 return (func_ptr_type) obj_main->entry;
415 _rtld_bind(Obj_Entry *obj, Elf_Word reloff)
419 const Obj_Entry *defobj;
425 rel = (const Elf_Rel *) ((caddr_t) obj->pltrel + reloff);
427 rel = (const Elf_Rel *) ((caddr_t) obj->pltrela + reloff);
429 where = (Elf_Addr *) (obj->relocbase + rel->r_offset);
430 def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, true);
434 target = (Elf_Addr)(defobj->relocbase + def->st_value);
436 dbg("\"%s\" in \"%s\" ==> %p in \"%s\"",
437 defobj->strtab + def->st_name, basename(obj->path),
438 (void *)target, basename(defobj->path));
440 reloc_jmpslot(where, target);
446 * Error reporting function. Use it like printf. If formats the message
447 * into a buffer, and sets things up so that the next call to dlerror()
448 * will return the message.
451 _rtld_error(const char *fmt, ...)
453 static char buf[512];
457 vsnprintf(buf, sizeof buf, fmt, ap);
463 * Return a dynamically-allocated copy of the current error message, if any.
468 return error_message == NULL ? NULL : xstrdup(error_message);
472 * Restore the current error message from a copy which was previously saved
473 * by errmsg_save(). The copy is freed.
476 errmsg_restore(char *saved_msg)
478 if (saved_msg == NULL)
479 error_message = NULL;
481 _rtld_error("%s", saved_msg);
487 basename(const char *name)
489 const char *p = strrchr(name, '/');
490 return p != NULL ? p + 1 : name;
496 const char *msg = dlerror();
504 * Process a shared object's DYNAMIC section, and save the important
505 * information in its Obj_Entry structure.
508 digest_dynamic(Obj_Entry *obj)
511 Needed_Entry **needed_tail = &obj->needed;
512 const Elf_Dyn *dyn_rpath = NULL;
513 int plttype = DT_REL;
515 for (dynp = obj->dynamic; dynp->d_tag != DT_NULL; dynp++) {
516 switch (dynp->d_tag) {
519 obj->rel = (const Elf_Rel *) (obj->relocbase + dynp->d_un.d_ptr);
523 obj->relsize = dynp->d_un.d_val;
527 assert(dynp->d_un.d_val == sizeof(Elf_Rel));
531 obj->pltrel = (const Elf_Rel *)
532 (obj->relocbase + dynp->d_un.d_ptr);
536 obj->pltrelsize = dynp->d_un.d_val;
540 obj->rela = (const Elf_Rela *) (obj->relocbase + dynp->d_un.d_ptr);
544 obj->relasize = dynp->d_un.d_val;
548 assert(dynp->d_un.d_val == sizeof(Elf_Rela));
552 plttype = dynp->d_un.d_val;
553 assert(dynp->d_un.d_val == DT_REL || plttype == DT_RELA);
557 obj->symtab = (const Elf_Sym *)
558 (obj->relocbase + dynp->d_un.d_ptr);
562 assert(dynp->d_un.d_val == sizeof(Elf_Sym));
566 obj->strtab = (const char *) (obj->relocbase + dynp->d_un.d_ptr);
570 obj->strsize = dynp->d_un.d_val;
575 const Elf_Addr *hashtab = (const Elf_Addr *)
576 (obj->relocbase + dynp->d_un.d_ptr);
577 obj->nbuckets = hashtab[0];
578 obj->nchains = hashtab[1];
579 obj->buckets = hashtab + 2;
580 obj->chains = obj->buckets + obj->nbuckets;
586 Needed_Entry *nep = NEW(Needed_Entry);
587 nep->name = dynp->d_un.d_val;
592 needed_tail = &nep->next;
597 obj->pltgot = (Elf_Addr *) (obj->relocbase + dynp->d_un.d_ptr);
605 obj->symbolic = true;
610 * We have to wait until later to process this, because we
611 * might not have gotten the address of the string table yet.
617 /* Not used by the dynamic linker. */
621 obj->init = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr);
625 obj->fini = (InitFunc) (obj->relocbase + dynp->d_un.d_ptr);
629 /* XXX - not implemented yet */
630 dbg("Filling in DT_DEBUG entry");
631 ((Elf_Dyn*)dynp)->d_un.d_ptr = (Elf_Addr) &r_debug;
635 dbg("Ignoring d_tag %d = %#x", dynp->d_tag, dynp->d_tag);
642 if (plttype == DT_RELA) {
643 obj->pltrela = (const Elf_Rela *) obj->pltrel;
645 obj->pltrelasize = obj->pltrelsize;
649 if (dyn_rpath != NULL)
650 obj->rpath = obj->strtab + dyn_rpath->d_un.d_val;
654 * Process a shared object's program header. This is used only for the
655 * main program, when the kernel has already loaded the main program
656 * into memory before calling the dynamic linker. It creates and
657 * returns an Obj_Entry structure.
660 digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path)
663 const Elf_Phdr *phlimit = phdr + phnum;
668 for (ph = phdr; ph < phlimit; ph++) {
669 switch (ph->p_type) {
672 if ((const Elf_Phdr *)ph->p_vaddr != phdr) {
673 _rtld_error("%s: invalid PT_PHDR", path);
676 obj->phdr = (const Elf_Phdr *) ph->p_vaddr;
677 obj->phsize = ph->p_memsz;
681 obj->interp = (const char *) ph->p_vaddr;
686 _rtld_error("%s: too many PT_LOAD segments", path);
689 if (nsegs == 0) { /* First load segment */
690 obj->vaddrbase = trunc_page(ph->p_vaddr);
691 obj->mapbase = (caddr_t) obj->vaddrbase;
692 obj->relocbase = obj->mapbase - obj->vaddrbase;
693 obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) -
695 } else { /* Last load segment */
696 obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) -
703 obj->dynamic = (const Elf_Dyn *) ph->p_vaddr;
708 _rtld_error("%s: too few PT_LOAD segments", path);
717 dlcheck(void *handle)
721 for (obj = obj_list; obj != NULL; obj = obj->next)
722 if (obj == (Obj_Entry *) handle)
725 if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) {
726 _rtld_error("Invalid shared object handle %p", handle);
733 * If the given object is already in the donelist, return true. Otherwise
734 * add the object to the list and return false.
737 donelist_check(DoneList *dlp, const Obj_Entry *obj)
741 for (i = 0; i < dlp->num_used; i++)
742 if (dlp->objs[i] == obj)
745 * Our donelist allocation should always be sufficient. But if
746 * our threads locking isn't working properly, more shared objects
747 * could have been loaded since we allocated the list. That should
748 * never happen, but we'll handle it properly just in case it does.
750 if (dlp->num_used < dlp->num_alloc)
751 dlp->objs[dlp->num_used++] = obj;
756 * Hash function for symbol table lookup. Don't even think about changing
757 * this. It is specified by the System V ABI.
760 elf_hash(const char *name)
762 const unsigned char *p = (const unsigned char *) name;
768 if ((g = h & 0xf0000000) != 0)
776 * Find the library with the given name, and return its full pathname.
777 * The returned string is dynamically allocated. Generates an error
778 * message and returns NULL if the library cannot be found.
780 * If the second argument is non-NULL, then it refers to an already-
781 * loaded shared object, whose library search path will be searched.
783 * The search order is:
784 * rpath in the referencing file
790 find_library(const char *name, const Obj_Entry *refobj)
794 if (strchr(name, '/') != NULL) { /* Hard coded pathname */
795 if (name[0] != '/' && !trust) {
796 _rtld_error("Absolute pathname required for shared object \"%s\"",
800 return xstrdup(name);
803 dbg(" Searching for \"%s\"", name);
805 if ((refobj != NULL &&
806 (pathname = search_library_path(name, refobj->rpath)) != NULL) ||
807 (pathname = search_library_path(name, ld_library_path)) != NULL ||
808 (pathname = search_library_path(name, gethints())) != NULL ||
809 (pathname = search_library_path(name, STANDARD_LIBRARY_PATH)) != NULL)
812 _rtld_error("Shared object \"%s\" not found", name);
817 * Given a symbol number in a referencing object, find the corresponding
818 * definition of the symbol. Returns a pointer to the symbol, or NULL if
819 * no definition was found. Returns a pointer to the Obj_Entry of the
820 * defining object via the reference parameter DEFOBJ_OUT.
823 find_symdef(unsigned long symnum, const Obj_Entry *refobj,
824 const Obj_Entry **defobj_out, bool in_plt)
828 const Obj_Entry *defobj;
832 ref = refobj->symtab + symnum;
833 name = refobj->strtab + ref->st_name;
834 hash = elf_hash(name);
837 def = symlook_default(name, hash, refobj, &defobj, in_plt);
840 * If we found no definition and the reference is weak, treat the
841 * symbol as having the value zero.
843 if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) {
849 *defobj_out = defobj;
851 _rtld_error("%s: Undefined symbol \"%s\"", refobj->path, name);
856 * Return the search path from the ldconfig hints file, reading it if
857 * necessary. Returns NULL if there are problems with the hints file,
858 * or if the search path there is empty.
867 struct elfhints_hdr hdr;
870 /* Keep from trying again in case the hints file is bad. */
873 if ((fd = open(_PATH_ELF_HINTS, O_RDONLY)) == -1)
875 if (read(fd, &hdr, sizeof hdr) != sizeof hdr ||
876 hdr.magic != ELFHINTS_MAGIC ||
881 p = xmalloc(hdr.dirlistlen + 1);
882 if (lseek(fd, hdr.strtab + hdr.dirlist, SEEK_SET) == -1 ||
883 read(fd, p, hdr.dirlistlen + 1) != hdr.dirlistlen + 1) {
891 return hints[0] != '\0' ? hints : NULL;
895 init_dag(Obj_Entry *root)
899 donelist_init(&donelist);
900 init_dag1(root, root, &donelist);
904 init_dag1(Obj_Entry *root, Obj_Entry *obj, DoneList *dlp)
906 const Needed_Entry *needed;
908 if (donelist_check(dlp, obj))
910 objlist_push_tail(&obj->dldags, root);
911 objlist_push_tail(&root->dagmembers, obj);
912 for (needed = obj->needed; needed != NULL; needed = needed->next)
913 if (needed->obj != NULL)
914 init_dag1(root, needed->obj, dlp);
918 * Initialize the dynamic linker. The argument is the address at which
919 * the dynamic linker has been mapped into memory. The primary task of
920 * this function is to relocate the dynamic linker.
923 init_rtld(caddr_t mapbase)
926 * Conjure up an Obj_Entry structure for the dynamic linker.
928 * The "path" member is supposed to be dynamically-allocated, but we
929 * aren't yet initialized sufficiently to do that. Below we will
930 * replace the static version with a dynamically-allocated copy.
932 obj_rtld.path = PATH_RTLD;
933 obj_rtld.rtld = true;
934 obj_rtld.mapbase = mapbase;
936 obj_rtld.relocbase = mapbase;
938 if (&_DYNAMIC != 0) {
939 obj_rtld.dynamic = rtld_dynamic(&obj_rtld);
940 digest_dynamic(&obj_rtld);
941 assert(obj_rtld.needed == NULL);
942 assert(!obj_rtld.textrel);
945 * Temporarily put the dynamic linker entry into the object list, so
946 * that symbols can be found.
948 obj_list = &obj_rtld;
949 obj_tail = &obj_rtld.next;
952 relocate_objects(&obj_rtld, true);
955 /* Make the object list empty again. */
957 obj_tail = &obj_list;
960 /* Replace the path with a dynamically allocated copy. */
961 obj_rtld.path = xstrdup(obj_rtld.path);
963 r_debug.r_brk = r_debug_state;
964 r_debug.r_state = RT_CONSISTENT;
968 * Add the init functions from a needed object list (and its recursive
969 * needed objects) to "list". This is not used directly; it is a helper
970 * function for initlist_add_objects(). The write lock must be held
971 * when this function is called.
974 initlist_add_neededs(Needed_Entry *needed, Objlist *list)
976 /* Recursively process the successor needed objects. */
977 if (needed->next != NULL)
978 initlist_add_neededs(needed->next, list);
980 /* Process the current needed object. */
981 if (needed->obj != NULL)
982 initlist_add_objects(needed->obj, &needed->obj->next, list);
986 * Scan all of the DAGs rooted in the range of objects from "obj" to
987 * "tail" and add their init functions to "list". This recurses over
988 * the DAGs and ensure the proper init ordering such that each object's
989 * needed libraries are initialized before the object itself. At the
990 * same time, this function adds the objects to the global finalization
991 * list "list_fini" in the opposite order. The write lock must be
992 * held when this function is called.
995 initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
999 obj->init_done = true;
1001 /* Recursively process the successor objects. */
1002 if (&obj->next != tail)
1003 initlist_add_objects(obj->next, tail, list);
1005 /* Recursively process the needed objects. */
1006 if (obj->needed != NULL)
1007 initlist_add_neededs(obj->needed, list);
1009 /* Add the object to the init list. */
1010 if (obj->init != NULL)
1011 objlist_push_tail(list, obj);
1013 /* Add the object to the global fini list in the reverse order. */
1014 if (obj->fini != NULL)
1015 objlist_push_head(&list_fini, obj);
1019 is_exported(const Elf_Sym *def)
1021 func_ptr_type value;
1022 const func_ptr_type *p;
1024 value = (func_ptr_type)(obj_rtld.relocbase + def->st_value);
1025 for (p = exports; *p != NULL; p++)
1032 * Given a shared object, traverse its list of needed objects, and load
1033 * each of them. Returns 0 on success. Generates an error message and
1034 * returns -1 on failure.
1037 load_needed_objects(Obj_Entry *first)
1041 for (obj = first; obj != NULL; obj = obj->next) {
1042 Needed_Entry *needed;
1044 for (needed = obj->needed; needed != NULL; needed = needed->next) {
1045 const char *name = obj->strtab + needed->name;
1046 char *path = find_library(name, obj);
1049 if (path == NULL && !ld_tracing)
1053 needed->obj = load_object(path);
1054 if (needed->obj == NULL && !ld_tracing)
1055 return -1; /* XXX - cleanup */
1064 load_preload_objects(void)
1066 char *p = ld_preload;
1067 static const char delim[] = " \t:;";
1072 p += strspn(p, delim);
1073 while (*p != '\0') {
1074 size_t len = strcspn(p, delim);
1080 if ((path = find_library(p, NULL)) == NULL)
1082 if (load_object(path) == NULL)
1083 return -1; /* XXX - cleanup */
1086 p += strspn(p, delim);
1092 * Load a shared object into memory, if it is not already loaded. The
1093 * argument must be a string allocated on the heap. This function assumes
1094 * responsibility for freeing it when necessary.
1096 * Returns a pointer to the Obj_Entry for the object. Returns NULL
1100 load_object(char *path)
1106 for (obj = obj_list->next; obj != NULL; obj = obj->next)
1107 if (strcmp(obj->path, path) == 0)
1111 * If we didn't find a match by pathname, open the file and check
1112 * again by device and inode. This avoids false mismatches caused
1113 * by multiple links or ".." in pathnames.
1115 * To avoid a race, we open the file and use fstat() rather than
1119 if ((fd = open(path, O_RDONLY)) == -1) {
1120 _rtld_error("Cannot open \"%s\"", path);
1123 if (fstat(fd, &sb) == -1) {
1124 _rtld_error("Cannot fstat \"%s\"", path);
1128 for (obj = obj_list->next; obj != NULL; obj = obj->next) {
1129 if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) {
1136 if (obj == NULL) { /* First use of this object, so we must map it in */
1137 dbg("loading \"%s\"", path);
1138 obj = map_object(fd, path, &sb);
1146 digest_dynamic(obj);
1149 obj_tail = &obj->next;
1151 linkmap_add(obj); /* for GDB */
1153 dbg(" %p .. %p: %s", obj->mapbase,
1154 obj->mapbase + obj->mapsize - 1, obj->path);
1156 dbg(" WARNING: %s has impure text", obj->path);
1165 * Check for locking violations and die if one is found.
1172 rcount = lockinfo.rcount;
1173 wcount = lockinfo.wcount;
1174 assert(rcount >= 0);
1175 assert(wcount >= 0);
1176 if (wcount > 1 || (wcount != 0 && rcount != 0)) {
1177 _rtld_error("Application locking error: %d readers and %d writers"
1178 " in dynamic linker. See DLLOCKINIT(3) in manual pages.",
1185 obj_from_addr(const void *addr)
1187 unsigned long endhash;
1190 endhash = elf_hash(END_SYM);
1191 for (obj = obj_list; obj != NULL; obj = obj->next) {
1192 const Elf_Sym *endsym;
1194 if (addr < (void *) obj->mapbase)
1196 if ((endsym = symlook_obj(END_SYM, endhash, obj, true)) == NULL)
1197 continue; /* No "end" symbol?! */
1198 if (addr < (void *) (obj->relocbase + endsym->st_value))
1205 * Call the finalization functions for each of the objects in "list"
1206 * which are unreferenced. All of the objects are expected to have
1207 * non-NULL fini functions.
1210 objlist_call_fini(Objlist *list)
1216 * Preserve the current error message since a fini function might
1217 * call into the dynamic linker and overwrite it.
1219 saved_msg = errmsg_save();
1220 STAILQ_FOREACH(elm, list, link) {
1221 if (elm->obj->refcount == 0) {
1222 dbg("calling fini function for %s", elm->obj->path);
1223 (*elm->obj->fini)();
1226 errmsg_restore(saved_msg);
1230 * Call the initialization functions for each of the objects in
1231 * "list". All of the objects are expected to have non-NULL init
1235 objlist_call_init(Objlist *list)
1241 * Preserve the current error message since an init function might
1242 * call into the dynamic linker and overwrite it.
1244 saved_msg = errmsg_save();
1245 STAILQ_FOREACH(elm, list, link) {
1246 dbg("calling init function for %s", elm->obj->path);
1247 (*elm->obj->init)();
1249 errmsg_restore(saved_msg);
1253 objlist_clear(Objlist *list)
1257 while (!STAILQ_EMPTY(list)) {
1258 elm = STAILQ_FIRST(list);
1259 STAILQ_REMOVE_HEAD(list, link);
1264 static Objlist_Entry *
1265 objlist_find(Objlist *list, const Obj_Entry *obj)
1269 STAILQ_FOREACH(elm, list, link)
1270 if (elm->obj == obj)
1276 objlist_init(Objlist *list)
1282 objlist_push_head(Objlist *list, Obj_Entry *obj)
1286 elm = NEW(Objlist_Entry);
1288 STAILQ_INSERT_HEAD(list, elm, link);
1292 objlist_push_tail(Objlist *list, Obj_Entry *obj)
1296 elm = NEW(Objlist_Entry);
1298 STAILQ_INSERT_TAIL(list, elm, link);
1302 objlist_remove(Objlist *list, Obj_Entry *obj)
1306 if ((elm = objlist_find(list, obj)) != NULL) {
1307 STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link);
1313 * Remove all of the unreferenced objects from "list".
1316 objlist_remove_unref(Objlist *list)
1321 STAILQ_INIT(&newlist);
1322 while (!STAILQ_EMPTY(list)) {
1323 elm = STAILQ_FIRST(list);
1324 STAILQ_REMOVE_HEAD(list, link);
1325 if (elm->obj->refcount == 0)
1328 STAILQ_INSERT_TAIL(&newlist, elm, link);
1334 * Relocate newly-loaded shared objects. The argument is a pointer to
1335 * the Obj_Entry for the first such object. All objects from the first
1336 * to the end of the list of objects are relocated. Returns 0 on success,
1340 relocate_objects(Obj_Entry *first, bool bind_now)
1344 for (obj = first; obj != NULL; obj = obj->next) {
1345 if (obj != &obj_rtld)
1346 dbg("relocating \"%s\"", obj->path);
1347 if (obj->nbuckets == 0 || obj->nchains == 0 || obj->buckets == NULL ||
1348 obj->symtab == NULL || obj->strtab == NULL) {
1349 _rtld_error("%s: Shared object has no run-time symbol table",
1355 /* There are relocations to the write-protected text segment. */
1356 if (mprotect(obj->mapbase, obj->textsize,
1357 PROT_READ|PROT_WRITE|PROT_EXEC) == -1) {
1358 _rtld_error("%s: Cannot write-enable text segment: %s",
1359 obj->path, strerror(errno));
1364 /* Process the non-PLT relocations. */
1365 if (reloc_non_plt(obj, &obj_rtld))
1368 if (obj->textrel) { /* Re-protected the text segment. */
1369 if (mprotect(obj->mapbase, obj->textsize,
1370 PROT_READ|PROT_EXEC) == -1) {
1371 _rtld_error("%s: Cannot write-protect text segment: %s",
1372 obj->path, strerror(errno));
1377 /* Process the PLT relocations. */
1378 if (reloc_plt(obj) == -1)
1380 /* Relocate the jump slots if we are doing immediate binding. */
1382 if (reloc_jmpslots(obj) == -1)
1387 * Set up the magic number and version in the Obj_Entry. These
1388 * were checked in the crt1.o from the original ElfKit, so we
1389 * set them for backward compatibility.
1391 obj->magic = RTLD_MAGIC;
1392 obj->version = RTLD_VERSION;
1394 /* Set the special PLT or GOT entries. */
1402 * Cleanup procedure. It will be called (by the atexit mechanism) just
1403 * before the process exits.
1412 /* Clear all the reference counts so the fini functions will be called. */
1413 for (obj = obj_list; obj != NULL; obj = obj->next)
1416 objlist_call_fini(&list_fini);
1417 /* No need to remove the items from the list, since we are exiting. */
1421 search_library_path(const char *name, const char *path)
1423 size_t namelen = strlen(name);
1424 const char *p = path;
1429 p += strspn(p, ":;");
1430 while (*p != '\0') {
1431 size_t len = strcspn(p, ":;");
1433 if (*p == '/' || trust) {
1435 const char *dir = p;
1436 size_t dirlen = len;
1438 pathname = xmalloc(dirlen + 1 + namelen + 1);
1439 strncpy(pathname, dir, dirlen);
1440 pathname[dirlen] = '/';
1441 strcpy(pathname + dirlen + 1, name);
1443 dbg(" Trying \"%s\"", pathname);
1444 if (access(pathname, F_OK) == 0) /* We found it */
1450 p += strspn(p, ":;");
1457 dlclose(void *handle)
1462 root = dlcheck(handle);
1468 /* Unreference the object and its dependencies. */
1469 root->dl_refcount--;
1472 if (root->refcount == 0) {
1474 * The object is no longer referenced, so we must unload it.
1475 * First, call the fini functions with no locks held.
1478 objlist_call_fini(&list_fini);
1480 objlist_remove_unref(&list_fini);
1482 /* Finish cleaning up the newly-unreferenced objects. */
1483 GDB_STATE(RT_DELETE,&root->linkmap);
1484 unload_object(root);
1485 GDB_STATE(RT_CONSISTENT,NULL);
1494 char *msg = error_message;
1495 error_message = NULL;
1500 * This function is deprecated and has no effect.
1503 dllockinit(void *context,
1504 void *(*lock_create)(void *context),
1505 void (*rlock_acquire)(void *lock),
1506 void (*wlock_acquire)(void *lock),
1507 void (*lock_release)(void *lock),
1508 void (*lock_destroy)(void *lock),
1509 void (*context_destroy)(void *context))
1511 static void *cur_context;
1512 static void (*cur_context_destroy)(void *);
1514 /* Just destroy the context from the previous call, if necessary. */
1515 if (cur_context_destroy != NULL)
1516 cur_context_destroy(cur_context);
1517 cur_context = context;
1518 cur_context_destroy = context_destroy;
1522 dlopen(const char *name, int mode)
1524 Obj_Entry **old_obj_tail;
1528 objlist_init(&initlist);
1531 GDB_STATE(RT_ADD,NULL);
1533 old_obj_tail = obj_tail;
1539 char *path = find_library(name, obj_main);
1541 obj = load_object(path);
1546 if (mode & RTLD_GLOBAL && objlist_find(&list_global, obj) == NULL)
1547 objlist_push_tail(&list_global, obj);
1548 mode &= RTLD_MODEMASK;
1549 if (*old_obj_tail != NULL) { /* We loaded something new. */
1550 assert(*old_obj_tail == obj);
1552 if (load_needed_objects(obj) == -1 ||
1553 (init_dag(obj), relocate_objects(obj, mode == RTLD_NOW)) == -1) {
1556 if (obj->refcount == 0)
1560 /* Make list of init functions to call. */
1561 initlist_add_objects(obj, &obj->next, &initlist);
1566 GDB_STATE(RT_CONSISTENT,obj ? &obj->linkmap : NULL);
1568 /* Call the init functions with no locks held. */
1570 objlist_call_init(&initlist);
1572 objlist_clear(&initlist);
1578 dlsym(void *handle, const char *name)
1580 const Obj_Entry *obj;
1583 const Obj_Entry *defobj;
1585 hash = elf_hash(name);
1590 if (handle == NULL || handle == RTLD_NEXT || handle == RTLD_DEFAULT) {
1593 retaddr = __builtin_return_address(0); /* __GNUC__ only */
1594 if ((obj = obj_from_addr(retaddr)) == NULL) {
1595 _rtld_error("Cannot determine caller's shared object");
1599 if (handle == NULL) { /* Just the caller's shared object. */
1600 def = symlook_obj(name, hash, obj, true);
1602 } else if (handle == RTLD_NEXT) { /* Objects after caller's */
1603 while ((obj = obj->next) != NULL) {
1604 if ((def = symlook_obj(name, hash, obj, true)) != NULL) {
1610 assert(handle == RTLD_DEFAULT);
1611 def = symlook_default(name, hash, obj, &defobj, true);
1614 if ((obj = dlcheck(handle)) == NULL) {
1619 if (obj->mainprog) {
1622 /* Search main program and all libraries loaded by it. */
1623 donelist_init(&donelist);
1624 def = symlook_list(name, hash, &list_main, &defobj, true,
1628 * XXX - This isn't correct. The search should include the whole
1629 * DAG rooted at the given object.
1631 def = symlook_obj(name, hash, obj, true);
1638 return defobj->relocbase + def->st_value;
1641 _rtld_error("Undefined symbol \"%s\"", name);
1647 dladdr(const void *addr, Dl_info *info)
1649 const Obj_Entry *obj;
1652 unsigned long symoffset;
1655 obj = obj_from_addr(addr);
1657 _rtld_error("No shared object contains address");
1661 info->dli_fname = obj->path;
1662 info->dli_fbase = obj->mapbase;
1663 info->dli_saddr = (void *)0;
1664 info->dli_sname = NULL;
1667 * Walk the symbol list looking for the symbol whose address is
1668 * closest to the address sent in.
1670 for (symoffset = 0; symoffset < obj->nchains; symoffset++) {
1671 def = obj->symtab + symoffset;
1674 * For skip the symbol if st_shndx is either SHN_UNDEF or
1677 if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON)
1681 * If the symbol is greater than the specified address, or if it
1682 * is further away from addr than the current nearest symbol,
1685 symbol_addr = obj->relocbase + def->st_value;
1686 if (symbol_addr > addr || symbol_addr < info->dli_saddr)
1689 /* Update our idea of the nearest symbol. */
1690 info->dli_sname = obj->strtab + def->st_name;
1691 info->dli_saddr = symbol_addr;
1694 if (info->dli_saddr == addr)
1702 linkmap_add(Obj_Entry *obj)
1704 struct link_map *l = &obj->linkmap;
1705 struct link_map *prev;
1707 obj->linkmap.l_name = obj->path;
1708 obj->linkmap.l_addr = obj->mapbase;
1709 obj->linkmap.l_ld = obj->dynamic;
1711 /* GDB needs load offset on MIPS to use the symbols */
1712 obj->linkmap.l_offs = obj->relocbase;
1715 if (r_debug.r_map == NULL) {
1721 * Scan to the end of the list, but not past the entry for the
1722 * dynamic linker, which we want to keep at the very end.
1724 for (prev = r_debug.r_map;
1725 prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap;
1726 prev = prev->l_next)
1729 /* Link in the new entry. */
1731 l->l_next = prev->l_next;
1732 if (l->l_next != NULL)
1733 l->l_next->l_prev = l;
1738 linkmap_delete(Obj_Entry *obj)
1740 struct link_map *l = &obj->linkmap;
1742 if (l->l_prev == NULL) {
1743 if ((r_debug.r_map = l->l_next) != NULL)
1744 l->l_next->l_prev = NULL;
1748 if ((l->l_prev->l_next = l->l_next) != NULL)
1749 l->l_next->l_prev = l->l_prev;
1753 * Function for the debugger to set a breakpoint on to gain control.
1755 * The two parameters allow the debugger to easily find and determine
1756 * what the runtime loader is doing and to whom it is doing it.
1758 * When the loadhook trap is hit (r_debug_state, set at program
1759 * initialization), the arguments can be found on the stack:
1761 * +8 struct link_map *m
1762 * +4 struct r_debug *rd
1766 r_debug_state(struct r_debug* rd, struct link_map *m)
1771 * Set a pointer variable in the main program to the given value. This
1772 * is used to set key variables such as "environ" before any of the
1773 * init functions are called.
1776 set_program_var(const char *name, const void *value)
1778 const Obj_Entry *obj;
1781 hash = elf_hash(name);
1782 for (obj = obj_main; obj != NULL; obj = obj->next) {
1785 if ((def = symlook_obj(name, hash, obj, false)) != NULL) {
1788 addr = (const void **)(obj->relocbase + def->st_value);
1789 dbg("\"%s\": *%p <-- %p", name, addr, value);
1797 * Given a symbol name in a referencing object, find the corresponding
1798 * definition of the symbol. Returns a pointer to the symbol, or NULL if
1799 * no definition was found. Returns a pointer to the Obj_Entry of the
1800 * defining object via the reference parameter DEFOBJ_OUT.
1802 static const Elf_Sym *
1803 symlook_default(const char *name, unsigned long hash,
1804 const Obj_Entry *refobj, const Obj_Entry **defobj_out, bool in_plt)
1808 const Elf_Sym *symp;
1809 const Obj_Entry *obj;
1810 const Obj_Entry *defobj;
1811 const Objlist_Entry *elm;
1814 donelist_init(&donelist);
1816 /* Look first in the referencing object if linked symbolically. */
1817 if (refobj->symbolic && !donelist_check(&donelist, refobj)) {
1818 symp = symlook_obj(name, hash, refobj, in_plt);
1825 /* Search all objects loaded at program start up. */
1826 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
1827 symp = symlook_list(name, hash, &list_main, &obj, in_plt, &donelist);
1829 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
1835 /* Search all dlopened DAGs containing the referencing object. */
1836 STAILQ_FOREACH(elm, &refobj->dldags, link) {
1837 if (def != NULL && ELF_ST_BIND(def->st_info) != STB_WEAK)
1839 symp = symlook_list(name, hash, &elm->obj->dagmembers, &obj, in_plt,
1842 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
1848 /* Search all RTLD_GLOBAL objects. */
1849 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
1850 symp = symlook_list(name, hash, &list_global, &obj, in_plt, &donelist);
1852 (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK)) {
1859 * Search the dynamic linker itself, and possibly resolve the
1860 * symbol from there. This is how the application links to
1861 * dynamic linker services such as dlopen. Only the values listed
1862 * in the "exports" array can be resolved from the dynamic linker.
1864 if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) {
1865 symp = symlook_obj(name, hash, &obj_rtld, in_plt);
1866 if (symp != NULL && is_exported(symp)) {
1873 *defobj_out = defobj;
1877 static const Elf_Sym *
1878 symlook_list(const char *name, unsigned long hash, Objlist *objlist,
1879 const Obj_Entry **defobj_out, bool in_plt, DoneList *dlp)
1881 const Elf_Sym *symp;
1883 const Obj_Entry *defobj;
1884 const Objlist_Entry *elm;
1888 STAILQ_FOREACH(elm, objlist, link) {
1889 if (donelist_check(dlp, elm->obj))
1891 if ((symp = symlook_obj(name, hash, elm->obj, in_plt)) != NULL) {
1892 if (def == NULL || ELF_ST_BIND(symp->st_info) != STB_WEAK) {
1895 if (ELF_ST_BIND(def->st_info) != STB_WEAK)
1901 *defobj_out = defobj;
1906 * Search the symbol table of a single shared object for a symbol of
1907 * the given name. Returns a pointer to the symbol, or NULL if no
1908 * definition was found.
1910 * The symbol's hash value is passed in for efficiency reasons; that
1911 * eliminates many recomputations of the hash value.
1914 symlook_obj(const char *name, unsigned long hash, const Obj_Entry *obj,
1917 if (obj->buckets != NULL) {
1918 unsigned long symnum = obj->buckets[hash % obj->nbuckets];
1920 while (symnum != STN_UNDEF) {
1921 const Elf_Sym *symp;
1924 if (symnum >= obj->nchains)
1925 return NULL; /* Bad object */
1926 symp = obj->symtab + symnum;
1927 strp = obj->strtab + symp->st_name;
1929 if (strcmp(name, strp) == 0)
1930 return symp->st_shndx != SHN_UNDEF ||
1931 (!in_plt && symp->st_value != 0 &&
1932 ELF_ST_TYPE(symp->st_info) == STT_FUNC) ? symp : NULL;
1934 symnum = obj->chains[symnum];
1941 trace_loaded_objects(Obj_Entry *obj)
1943 char *fmt1, *fmt2, *fmt, *main_local;
1946 if ((main_local = getenv("LD_TRACE_LOADED_OBJECTS_PROGNAME")) == NULL)
1949 if ((fmt1 = getenv("LD_TRACE_LOADED_OBJECTS_FMT1")) == NULL)
1950 fmt1 = "\t%o => %p (%x)\n";
1952 if ((fmt2 = getenv("LD_TRACE_LOADED_OBJECTS_FMT2")) == NULL)
1953 fmt2 = "\t%o (%x)\n";
1955 for (; obj; obj = obj->next) {
1956 Needed_Entry *needed;
1960 for (needed = obj->needed; needed; needed = needed->next) {
1961 if (needed->obj != NULL) {
1962 if (needed->obj->traced)
1964 needed->obj->traced = true;
1965 path = needed->obj->path;
1969 name = (char *)obj->strtab + needed->name;
1970 is_lib = strncmp(name, "lib", 3) == 0; /* XXX - bogus */
1972 fmt = is_lib ? fmt1 : fmt2;
1973 while ((c = *fmt++) != '\0') {
1999 printf("%s", main_local);
2002 printf("%s", obj_main->path);
2009 printf("%d", sodp->sod_major);
2012 printf("%d", sodp->sod_minor);
2019 printf("%p", needed->obj ? needed->obj->mapbase : 0);
2031 * Unload a dlopened object and its dependencies from memory and from
2032 * our data structures. It is assumed that the DAG rooted in the
2033 * object has already been unreferenced, and that the object has a
2034 * reference count of 0.
2037 unload_object(Obj_Entry *root)
2043 assert(root->refcount == 0);
2045 /* Remove the DAG from all objects' DAG lists. */
2046 STAILQ_FOREACH(elm, &root->dagmembers , link)
2047 objlist_remove(&elm->obj->dldags, root);
2049 /* Remove the DAG from the RTLD_GLOBAL list. */
2050 objlist_remove(&list_global, root);
2052 /* Unmap all objects that are no longer referenced. */
2053 linkp = &obj_list->next;
2054 while ((obj = *linkp) != NULL) {
2055 if (obj->refcount == 0) {
2056 dbg("unloading \"%s\"", obj->path);
2057 munmap(obj->mapbase, obj->mapsize);
2058 linkmap_delete(obj);
2069 unref_dag(Obj_Entry *root)
2071 const Needed_Entry *needed;
2073 if (root->refcount == 0)
2076 if (root->refcount == 0)
2077 for (needed = root->needed; needed != NULL; needed = needed->next)
2078 if (needed->obj != NULL)
2079 unref_dag(needed->obj);
2083 * Non-mallocing printf, for use by malloc itself.
2084 * XXX - This doesn't belong in this module.
2087 xprintf(const char *fmt, ...)
2093 vsprintf(buf, fmt, ap);
2094 (void)write(1, buf, strlen(buf));