/* $OpenBSD: library_mquery.c,v 1.13 2003/09/02 15:17:51 drahn Exp $ */ /* * Copyright (c) 2002 Dale Rahn * Copyright (c) 1998 Per Fogelstrom, Opsycon AB * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * */ #define _DYN_LOADER #include #include #include #include #include #include #include #include #include "syscall.h" #include "archdep.h" #include "resolve.h" #include "dir.h" #include "sod.h" #define DEFAULT_PATH "/usr/lib" #define PFLAGS(X) ((((X) & PF_R) ? PROT_READ : 0) | \ (((X) & PF_W) ? PROT_WRITE : 0) | \ (((X) & PF_X) ? PROT_EXEC : 0)) elf_object_t *_dl_tryload_shlib(const char *libname, int type); /* * _dl_match_file() * * This fucntion determines if a given name matches what is specified * in a struct sod. The major must match exactly, and the minor must * be same or larger. * * sodp is updated with the minor if this matches. */ int _dl_match_file(struct sod *sodp, char *name, int namelen) { int match; struct sod lsod; char *lname; lname = name; if (sodp->sod_library) { if (_dl_strncmp(name, "lib", 3)) return 0; lname += 3; } if (_dl_strncmp(lname, (char *)sodp->sod_name, _dl_strlen((char *)sodp->sod_name))) return 0; _dl_build_sod(name, &lsod); match = 0; if ((_dl_strcmp((char *)lsod.sod_name, (char *)sodp->sod_name) == 0) && (lsod.sod_library == sodp->sod_library) && ((sodp->sod_major == -1) || (sodp->sod_major == lsod.sod_major)) && ((sodp->sod_minor == -1) || (lsod.sod_minor >= sodp->sod_minor))) { match = 1; /* return version matched */ sodp->sod_major = lsod.sod_major; sodp->sod_minor = lsod.sod_minor; } _dl_free((char *)lsod.sod_name); return match; } char _dl_hint_store[MAXPATHLEN]; char * _dl_find_shlib(struct sod *sodp, const char *searchpath, int nohints) { char *hint, lp[PATH_MAX + 10], *path; struct dirent *dp; const char *pp; int match, len; DIR *dd; struct sod tsod, bsod; /* transient and best sod */ /* if we are to search default directories, and hints * are not to be used, search the standard path from ldconfig * (_dl_hint_search_path) or use the default path */ if (nohints) goto nohints; if (searchpath == NULL) { /* search 'standard' locations, find any match in the hints */ hint = _dl_findhint((char *)sodp->sod_name, sodp->sod_major, sodp->sod_minor, NULL); if (hint) return hint; } else { /* search hints requesting matches for only * the searchpath directories, */ pp = searchpath; while (pp) { path = lp; while (path < lp + PATH_MAX && *pp && *pp != ':' && *pp != ';') *path++ = *pp++; *path = 0; hint = _dl_findhint((char *)sodp->sod_name, sodp->sod_major, sodp->sod_minor, lp); if (hint != NULL) return hint; if (*pp) /* Try curdir if ':' at end */ pp++; else pp = 0; } } /* * For each directory in the searchpath, read the directory * entries looking for a match to sod. filename compare is * done by _dl_match_file() */ nohints: if (searchpath == NULL) { if (_dl_hint_search_path != NULL) searchpath = _dl_hint_search_path; else searchpath = DEFAULT_PATH; } pp = searchpath; while (pp) { path = lp; while (path < lp + PATH_MAX && *pp && *pp != ':' && *pp != ';') *path++ = *pp++; *path = 0; if ((dd = _dl_opendir(lp)) != NULL) { match = 0; while ((dp = _dl_readdir(dd)) != NULL) { tsod = *sodp; if (_dl_match_file(&tsod, dp->d_name, dp->d_namlen)) { /* * When a match is found, tsod is * updated with the major+minor found. * This version is compared with the * largest so far (kept in bsod), * and saved if larger. */ if (!match || tsod.sod_major == -1 || tsod.sod_major > bsod.sod_major || ((tsod.sod_major == bsod.sod_major) && tsod.sod_minor > bsod.sod_minor)) { bsod = tsod; match = 1; len = _dl_strlcpy( _dl_hint_store, lp, MAXPATHLEN); if (lp[len-1] != '/') { _dl_hint_store[len] = '/'; len++; } _dl_strlcpy( &_dl_hint_store[len], dp->d_name, MAXPATHLEN-len); if (tsod.sod_major == -1) break; } } } _dl_closedir(dd); if (match) { *sodp = bsod; return (_dl_hint_store); } } if (*pp) /* Try curdir if ':' at end */ pp++; else pp = 0; } return NULL; } /* * Load a shared object. Search order is: * If the name contains a '/' use the name exactly as is. (only) * try the LD_LIBRARY_PATH specification (if present) * search hints for match in LD_LIBRARY_PATH dirs * this will only match specific libary version. * search LD_LIBRARY_PATH dirs for match. * this will find largest minor version in first dir found. * check DT_RPATH paths, (if present) * search hints for match in DT_RPATH dirs * this will only match specific libary version. * search DT_RPATH dirs for match. * this will find largest minor version in first dir found. * last look in default search directory, either as specified * by ldconfig or default to '/usr/lib' */ elf_object_t * _dl_load_shlib(const char *libname, elf_object_t *parent, int type, int flags) { int try_any_minor, ignore_hints; struct sod sod, req_sod; elf_object_t *object; char *hint; try_any_minor = 0; ignore_hints = 0; if (_dl_strchr(libname, '/')) { object = _dl_tryload_shlib(libname, type); return(object); } _dl_build_sod(libname, &sod); req_sod = sod; again: /* * No '/' in name. Scan the known places, LD_LIBRARY_PATH first. */ if (_dl_libpath != NULL) { hint = _dl_find_shlib(&req_sod, _dl_libpath, ignore_hints); if (hint != NULL) { if (req_sod.sod_minor < sod.sod_minor) _dl_printf("warning: lib%s.so.%d.%d: " "minor version >= %d expected, " "using it anyway\n", sod.sod_name, sod.sod_major, req_sod.sod_minor, sod.sod_minor); object = _dl_tryload_shlib(hint, type); if (object != NULL) { _dl_free((char *)sod.sod_name); object->obj_flags = flags; return (object); } } } /* * Check DT_RPATH. */ if (parent->dyn.rpath != NULL) { hint = _dl_find_shlib(&req_sod, parent->dyn.rpath, ignore_hints); if (hint != NULL) { if (req_sod.sod_minor < sod.sod_minor) _dl_printf("warning: lib%s.so.%d.%d: " "minor version >= %d expected, " "using it anyway\n", sod.sod_name, sod.sod_major, req_sod.sod_minor, sod.sod_minor); object = _dl_tryload_shlib(hint, type); if (object != NULL) { _dl_free((char *)sod.sod_name); object->obj_flags = flags; return (object); } } } /* check 'standard' locations */ hint = _dl_find_shlib(&req_sod, NULL, ignore_hints); if (hint != NULL) { if (req_sod.sod_minor < sod.sod_minor) _dl_printf("warning: lib%s.so.%d.%d: " "minor version >= %d expected, " "using it anyway\n", sod.sod_name, sod.sod_major, req_sod.sod_minor, sod.sod_minor); object = _dl_tryload_shlib(hint, type); if (object != NULL) { _dl_free((char *)sod.sod_name); object->obj_flags = flags; return(object); } } if (try_any_minor == 0) { try_any_minor = 1; ignore_hints = 1; req_sod.sod_minor = -1; goto again; } _dl_free((char *)sod.sod_name); _dl_errno = DL_NOT_FOUND; return(0); } void _dl_load_list_free(struct load_list *load_list) { struct load_list *next; int align = _dl_pagesz - 1; while (load_list != NULL) { if (load_list->start != NULL) _dl_munmap(load_list->start, ((load_list->size) + align) & ~align); next = load_list->next; _dl_free(load_list); load_list = next; } } void _dl_run_dtors(elf_object_t *object); void _dl_unload_shlib(elf_object_t *object) { if (--object->refcount == 0) { _dl_run_dtors(object); _dl_load_list_free(object->load_list); _dl_remove_object(object); } } elf_object_t * _dl_tryload_shlib(const char *libname, int type) { int libfile, i, align = _dl_pagesz - 1; struct load_list *ld, *lowld = NULL; elf_object_t *object; char hbuf[4096]; Elf_Dyn *dynp = 0; Elf_Ehdr *ehdr; Elf_Phdr *phdp; int off; int size; Elf_Addr load_end = 0; #define ROUND_PG(x) (((x) + align) & ~(align)) #define TRUNC_PG(x) ((x) & ~(align)) object = _dl_lookup_object(libname); if (object) { object->refcount++; return(object); /* Already loaded */ } libfile = _dl_open(libname, O_RDONLY); if (libfile < 0) { _dl_errno = DL_CANT_OPEN; return(0); } _dl_read(libfile, hbuf, sizeof(hbuf)); ehdr = (Elf_Ehdr *)hbuf; if (ehdr->e_ident[0] != ELFMAG0 || ehdr->e_ident[1] != ELFMAG1 || ehdr->e_ident[2] != ELFMAG2 || ehdr->e_ident[3] != ELFMAG3 || ehdr->e_type != ET_DYN || ehdr->e_machine != MACHID) { _dl_close(libfile); _dl_errno = DL_NOT_ELF; return(0); } /* Insertion sort */ #define LDLIST_INSERT(ld) do { \ struct load_list **_ld; \ for (_ld = &lowld; *_ld != NULL; _ld = &(*_ld)->next) \ if ((*_ld)->moff > ld->moff) \ break; \ ld->next = *_ld; \ *_ld = ld; \ } while (0) /* * Alright, we might have a winner! * Figure out how much VM space we need and set up the load * list that we'll use to find free VM space. */ phdp = (Elf_Phdr *)(hbuf + ehdr->e_phoff); for (i = 0; i < ehdr->e_phnum; i++, phdp++) { switch (phdp->p_type) { case PT_LOAD: off = (phdp->p_vaddr & align); size = off + phdp->p_filesz; ld = _dl_malloc(sizeof(struct load_list)); ld->start = NULL; ld->size = size; ld->moff = TRUNC_PG(phdp->p_vaddr); ld->foff = TRUNC_PG(phdp->p_offset); ld->prot = PFLAGS(phdp->p_flags); LDLIST_INSERT(ld); if ((ld->prot & PROT_WRITE) == 0 || ROUND_PG(size) == ROUND_PG(off + phdp->p_memsz)) break; /* This phdr has a zfod section */ ld = _dl_malloc(sizeof(struct load_list)); ld->start = NULL; ld->size = ROUND_PG(off + phdp->p_memsz) - ROUND_PG(size); ld->moff = TRUNC_PG(phdp->p_vaddr) + ROUND_PG(size); ld->foff = -1; ld->prot = PFLAGS(phdp->p_flags); LDLIST_INSERT(ld); break; case PT_DYNAMIC: dynp = (Elf_Dyn *)phdp->p_vaddr; break; default: break; } } #define LOFF ((Elf_Addr)lowld->start - lowld->moff) retry: for (ld = lowld; ld != NULL; ld = ld->next) { off_t foff; int fd, flags; /* * We don't want to provide the fd/off hint for anything * but the first mapping, all other might have * cache-incoherent aliases and will cause this code to * loop forever. */ if (ld == lowld) { fd = libfile; foff = ld->foff; flags = 0; } else { fd = -1; foff = 0; flags = MAP_FIXED; } ld->start = (void *)(LOFF + ld->moff); /* * Magic here. * The first mquery is done with MAP_FIXED to see if * the mapping we want is free. If it's not, we redo the * mquery without MAP_FIXED to get the next free mapping, * adjust the base mapping address to match this free mapping * and restart the process again. */ ld->start = _dl_mquery(ld->start, ROUND_PG(ld->size), ld->prot, flags, fd, foff); if (_dl_check_error(ld->start)) { ld->start = (void *)(LOFF + ld->moff); ld->start = _dl_mquery(ld->start, ROUND_PG(ld->size), ld->prot, flags & ~MAP_FIXED, fd, foff); if (_dl_check_error(ld->start)) goto fail; } if (ld->start != (void *)(LOFF + ld->moff)) { lowld->start = ld->start - ld->moff + lowld->moff; goto retry; } /* * XXX - we need some kind of boundary condition here, * or fix mquery to not run into the stack */ } for (ld = lowld; ld != NULL; ld = ld->next) { off_t foff; int fd, flags; void *res; if (ld->foff < 0) { fd = -1; foff = 0; flags = MAP_FIXED|MAP_PRIVATE|MAP_ANON; } else { fd = libfile; foff = ld->foff; flags = MAP_FIXED|MAP_PRIVATE; } res = _dl_mmap(ld->start, ROUND_PG(ld->size), ld->prot, flags, fd, foff); if (_dl_check_error((long)res)) goto fail; /* Zero out everything past the EOF */ if ((ld->prot & PROT_WRITE) != 0 && (ld->size & align) != 0) _dl_memset((char *)ld->start + ld->size, 0, _dl_pagesz - (ld->size & align)); load_end = (Elf_Addr)ld->start + ROUND_PG(ld->size); } _dl_close(libfile); dynp = (Elf_Dyn *)((unsigned long)dynp + LOFF); object = _dl_finalize_object(libname, dynp, 0, type, (Elf_Addr)lowld->start, LOFF); if (object) { object->load_size = (Elf_Addr)load_end - (Elf_Addr)lowld->start; object->load_list = lowld; } else { _dl_load_list_free(lowld); } return(object); fail: _dl_printf("%s: rtld mmap failed mapping %s.\n", _dl_progname, libname); _dl_close(libfile); _dl_errno = DL_CANT_MMAP; _dl_load_list_free(lowld); return(0); } void _dl_link_sub(elf_object_t *dep, elf_object_t *p) { struct dep_node *n; n = _dl_malloc(sizeof *n); if (n == NULL) _dl_exit(5); n->data = dep; n->next_sibling = NULL; if (p->first_child) { p->last_child->next_sibling = n; p->last_child = n; } else p->first_child = p->last_child = n; DL_DEB(("linking dep %s as child of %s\n", dep->load_name, p->load_name)); }