diff options
Diffstat (limited to 'libexec/rtld-aout')
| -rw-r--r-- | libexec/rtld-aout/Makefile | 9 | ||||
| -rw-r--r-- | libexec/rtld-aout/rtld.c | 732 |
2 files changed, 474 insertions, 267 deletions
diff --git a/libexec/rtld-aout/Makefile b/libexec/rtld-aout/Makefile index 4177f6b..13c8de8 100644 --- a/libexec/rtld-aout/Makefile +++ b/libexec/rtld-aout/Makefile @@ -1,13 +1,12 @@ -# $Id: Makefile,v 1.23 1997/02/22 15:46:46 peter Exp $ - +# $Id: Makefile,v 1.24 1997/04/16 11:31:32 bde Exp $ PROG= ld.so -SRCS= mdprologue.S rtld.c malloc.c shlib.c md.c support.c sbrk.c +SRCS= mdprologue.S rtld.c shlib.c md.c support.c MAN1= rtld.1 LDDIR?= $(.CURDIR)/.. # As there is relocation going on behind GCC's back, don't cache function addresses. PICFLAG=-fpic -fno-function-cse -CFLAGS+=-I$(LDDIR) -I$(.CURDIR) -I$(LDDIR)/$(MACHINE) $(PICFLAG) -DRTLD -LDFLAGS+=-nostdlib -Wl,-Bshareable -Wl,-Bsymbolic -Wl,-assert -Wl,nosymbolic +CFLAGS+=-I$(LDDIR) -I$(.CURDIR) -I$(LDDIR)/$(MACHINE) $(PICFLAG) -DRTLD -Wall +LDFLAGS+=-nostdlib -Wl,-Bshareable,-Bsymbolic,-assert,nosymbolic ASFLAGS+=-k DPADD+= ${LIBC:S/c.a/c_pic.a/} ${LIBC:S/c.a/gcc_pic.a/} LDADD+= -lc_pic -lgcc_pic diff --git a/libexec/rtld-aout/rtld.c b/libexec/rtld-aout/rtld.c index e3debe5..efe912b 100644 --- a/libexec/rtld-aout/rtld.c +++ b/libexec/rtld-aout/rtld.c @@ -27,7 +27,7 @@ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * - * $Id: rtld.c,v 1.48 1997/08/19 23:33:45 nate Exp $ + * $Id: rtld.c,v 1.49 1997/09/18 13:55:45 phk Exp $ */ #include <sys/param.h> @@ -199,26 +199,31 @@ struct so_map *link_map_head; struct so_map *link_map_tail; struct rt_symbol *rt_symbol_head; -static void *__dlopen __P((char *, int)); +static void *__dlopen __P((const char *, int)); static int __dlclose __P((void *)); -static void *__dlsym __P((void *, char *)); -static char *__dlerror __P((void)); +static void *__dlsym __P((void *, const char *)); +static const char *__dlerror __P((void)); static void __dlexit __P((void)); -static void *__dlsym3 __P((void *, char *, void *)); +static void *__dlsym3 __P((void *, const char *, void *)); static struct ld_entry ld_entry = { __dlopen, __dlclose, __dlsym, __dlerror, __dlexit, __dlsym3 }; void xprintf __P((char *, ...)); -static struct so_map *map_object __P(( char *, +static struct so_map *map_object __P(( const char *, struct sod *, struct so_map *)); static int map_preload __P((void)); static int map_sods __P((struct so_map *)); -static int reloc_and_init __P((struct so_map *, int)); +static int reloc_dag __P((struct so_map *, int)); static void unmap_object __P((struct so_map *, int)); -static struct so_map *alloc_link_map __P(( char *, struct sod *, +static struct so_map *alloc_link_map __P(( const char *, struct sod *, + struct so_map *, caddr_t, + struct _dynamic *)); +static void init_link_map __P(( struct so_map *, + struct somap_private *, + const char *, struct sod *, struct so_map *, caddr_t, struct _dynamic *)); static void free_link_map __P((struct so_map *)); @@ -227,8 +232,10 @@ static inline int check_text_reloc __P(( struct relocation_info *, caddr_t)); static int reloc_map __P((struct so_map *, int)); static void reloc_copy __P((struct so_map *)); -static void init_object __P((struct so_map *)); +static void init_dag __P((struct so_map *)); static void init_sods __P((struct so_list *)); +static void init_internal_malloc __P((struct _dynamic *)); +static void init_external_malloc __P((void)); static int call_map __P((struct so_map *, char *)); static char *findhint __P((char *, int, int *)); static char *rtfindlib __P((char *, int, int)); @@ -236,9 +243,12 @@ static char *rtfindfile __P((char *)); void binder_entry __P((void)); long binder __P((jmpslot_t *)); static struct nzlist *lookup __P((char *, struct so_map **, int)); -static inline struct rt_symbol *lookup_rts __P((char *)); -static struct rt_symbol *enter_rts __P((char *, long, int, caddr_t, - long, struct so_map *)); +static inline struct rt_symbol *lookup_rts __P((char *, unsigned long)); +static struct nzlist *lookup_in_obj __P((char *, unsigned long, + struct so_map *, int)); +static struct rt_symbol *enter_rts __P((char *, unsigned long, long, int, + caddr_t, long, struct so_map *)); +static void *sym_addr __P((char *)); static void die __P((void)); static void generror __P((char *, ...)); static int maphints __P((void)); @@ -248,6 +258,23 @@ static void rt_readenv __P((void)); static int hinthash __P((char *, int)); int rtld __P((int, struct crt_ldso *, struct _dynamic *)); +/* + * Compute a hash value for symbol tables. Don't change this -- the + * algorithm is dictated by the way the linker builds the symbol + * tables in the shared objects. + */ +static inline unsigned long +sym_hash(s) + const char *s; +{ + unsigned long h; + + h = 0; + while (*s != '\0') + h = (h << 1) + *s++; + return h & 0x7fffffffUL; +} + static inline int strcmp (register const char *s1, register const char *s2) { @@ -319,6 +346,9 @@ struct _dynamic *dp; else crtp->crt_dp->d_entry = &ld_entry; /* _DYNAMIC */ + /* Initialize our internal malloc package. */ + init_internal_malloc(crtp->crt_dp); + /* Setup out (private) environ variable */ environ = crtp->crt_ep; @@ -380,10 +410,21 @@ struct _dynamic *dp; crtp->crt_dp->d_un.d_sdt->sdt_loaded = link_map_head->som_next; - /* Relocate and initialize all mapped objects */ - if(reloc_and_init(main_map, ld_bind_now != NULL) == -1) /* Failed */ + /* Relocate all mapped objects. */ + if(reloc_dag(main_map, ld_bind_now != NULL) == -1) /* Failed */ die(); + /* + * Switch to the same malloc that the program uses. We do + * this before initializing the loaded objects, because their + * initialization functions may well call malloc, and it won't + * work right until we have set it up. + */ + init_external_malloc(); + + /* Initialize all mapped objects. */ + init_dag(main_map); + ddp = crtp->crt_dp->d_debug; ddp->dd_cc = rt_symbol_head; if (ddp->dd_in_debugger) { @@ -513,9 +554,9 @@ ld_trace(smp) * ADDR is the address at which the object has been mapped. DP is a pointer * to its _dynamic structure. */ - static struct so_map * +static struct so_map * alloc_link_map(path, sodp, parent, addr, dp) - char *path; + const char *path; struct sod *sodp; struct so_map *parent; caddr_t addr; @@ -523,25 +564,16 @@ alloc_link_map(path, sodp, parent, addr, dp) { struct so_map *smp; struct somap_private *smpp; - size_t smp_size; #ifdef DEBUG /* { */ xprintf("alloc_link_map: \"%s\" at %p\n", path, addr); #endif /* } */ - /* - * Allocate so_map and private area with a single malloc. Round - * up the size of so_map so the private area is aligned. - */ - smp_size = ((((sizeof(struct so_map)) + sizeof (void *) - 1) / - sizeof (void *)) * sizeof (void *)); - - smp = (struct so_map *)xmalloc(smp_size + - sizeof (struct somap_private)); - smpp = (struct somap_private *) (((caddr_t) smp) + smp_size); + smp = (struct so_map *)xmalloc(sizeof(struct so_map)); + smpp = (struct somap_private *)xmalloc(sizeof(struct somap_private)); + init_link_map(smp, smpp, path, sodp, parent, addr, dp); /* Link the new entry into the list of link maps */ - smp->som_next = NULL; smpp->spd_prev = link_map_tail; if(link_map_tail == NULL) /* First link map entered into list */ link_map_head = link_map_tail = smp; @@ -550,31 +582,41 @@ alloc_link_map(path, sodp, parent, addr, dp) link_map_tail = smp; } + return smp; +} + +/* + * Initialize a link map entry that has already been allocated. + */ +static void +init_link_map(smp, smpp, path, sodp, parent, addr, dp) + struct so_map *smp; + struct somap_private *smpp; + const char *path; + struct sod *sodp; + struct so_map *parent; + caddr_t addr; + struct _dynamic *dp; +{ + memset(smp, 0, sizeof *smp); + memset(smpp, 0, sizeof *smpp); + smp->som_spd = (caddr_t)smpp; smp->som_addr = addr; smp->som_path = path ? strdup(path) : NULL; smp->som_sod = sodp; smp->som_dynamic = dp; - smp->som_spd = (caddr_t)smpp; - - smpp->spd_refcount = 0; - smpp->spd_flags = 0; smpp->spd_parent = parent; - smpp->spd_children = NULL; - smpp->a_text = 0; - smpp->a_data = 0; - smpp->a_bss = 0; #ifdef SUN_COMPAT smpp->spd_offset = (addr==0 && dp && dp->d_version==LD_VERSION_SUN) ? PAGSIZ : 0; #endif - return smp; } /* * Remove the specified link map entry from the list of link maps, and free * the associated storage. */ - static void +static void free_link_map(smp) struct so_map *smp; { @@ -594,7 +636,9 @@ free_link_map(smp) else /* Update back link of next entry */ LM_PRIVATE(smp->som_next)->spd_prev = smpp->spd_prev; - free(smp->som_path); + if (smp->som_path != NULL) + free(smp->som_path); + free(smpp); free(smp); } @@ -617,9 +661,9 @@ free_link_map(smp) * If the operation failed, the return value is NULL. In that case, an * error message can be retrieved by calling dlerror(). */ - static struct so_map * +static struct so_map * map_object(path, sodp, parent) - char *path; + const char *path; struct sod *sodp; struct so_map *parent; { @@ -821,7 +865,7 @@ map_preload __P((void)) { * Returns 0 on success. Returns -1 on failure. In that case, an error * message can be retrieved by calling dlerror(). */ - static int +static int map_sods(parent) struct so_map *parent; { @@ -872,7 +916,7 @@ map_sods(parent) */ (void)alloc_link_map(NULL, sodp, parent, 0, 0); } else if (ld_ignore_missing_objects) { - char *msg; + const char *msg; /* * Call __dlerror() even it we're not going to use * the message, in order to clear the saved message. @@ -915,12 +959,12 @@ map_sods(parent) } /* - * Relocate and initialize the tree of shared objects rooted at the given - * link map entry. Returns 0 on success, or -1 on failure. On failure, - * an error message can be retrieved via dlerror(). + * Relocate the DAG of shared objects rooted at the given link map + * entry. Returns 0 on success, or -1 on failure. On failure, an + * error message can be retrieved via dlerror(). */ - static int -reloc_and_init(root, bind_now) +static int +reloc_dag(root, bind_now) struct so_map *root; int bind_now; { @@ -957,35 +1001,6 @@ reloc_and_init(root, bind_now) reloc_copy(smp); } - /* - * Call any object initialization routines. - * - * Here, the order is very important, and we cannot simply loop - * over the newly-loaded objects as we did before. Rather, we - * have to initialize the tree of new objects depth-first, and - * process the sibling objects at each level in reverse order - * relative to the dependency list. - * - * Here is the reason we initialize depth-first. If an object - * depends on one or more other objects, then the objects it - * depends on should be initialized first, before the parent - * object itself. For it is possible that the parent's - * initialization routine will need the services provided by the - * objects it depends on -- and those objects had better already - * be initialized. - * - * We initialize the objects at each level of the tree in reverse - * order for a similar reason. When an object is linked with - * several libraries, it is common for routines in the earlier - * libraries to call routines in the later libraries. So, again, - * the later libraries need to be initialized first. - * - * The upshot of these rules is that we have to use recursion to - * get the libraries initialized in the best order. But the - * recursion is never likely to be very deep. - */ - init_object(root); - return 0; } @@ -1009,7 +1024,7 @@ reloc_and_init(root, bind_now) * anything goes wrong, we consider it an internal error, and report * it with err(). */ - static void +static void unmap_object(smp, keep) struct so_map *smp; int keep; @@ -1218,7 +1233,7 @@ reloc_map(smp, bind_now) relocation -= (long)smp->som_addr; if (RELOC_COPY_P(r) && src_map) { - (void)enter_rts(sym, + (void)enter_rts(sym, sym_hash(sym), (long)addr, N_DATA + N_EXT, src_map->som_addr + np->nz_value, @@ -1252,7 +1267,7 @@ reloc_map(smp, bind_now) return 0; } - static void +static void reloc_copy(smp) struct so_map *smp; { @@ -1266,8 +1281,11 @@ reloc_copy(smp) } } - static void -init_object(smp) +/* + * Initialize the DAG of shared objects rooted at the given object. + */ +static void +init_dag(smp) struct so_map *smp; { struct somap_private *smpp = LM_PRIVATE(smp); @@ -1284,7 +1302,7 @@ init_object(smp) } } - static void +static void init_sods(solp) struct so_list *solp; { @@ -1293,7 +1311,7 @@ init_sods(solp) init_sods(solp->sol_next); /* Initialize the first element of the list */ - init_object(solp->sol_map); + init_dag(solp->sol_map); } @@ -1304,7 +1322,7 @@ init_sods(solp) * Returns 0 on success, or -1 if the symbol was not found. Failure is not * necessarily an error condition, so no error message is generated. */ - static int +static int call_map(smp, sym) struct so_map *smp; char *sym; @@ -1329,69 +1347,46 @@ call_map(smp, sym) static struct rt_symbol *rt_symtab[RTC_TABSIZE]; /* - * Compute hash value for run-time symbol table + * Look up a symbol in the run-time common symbol table. For efficiency, + * the symbol's hash value must be passed in too. */ - static inline int -hash_string(key) - char *key; -{ - register char *cp; - register int k; - - cp = key; - k = 0; - while (*cp) - k = (((k << 1) + (k >> 14)) ^ (*cp++)) & 0x3fff; - - return k; -} - -/* - * Lookup KEY in the run-time common symbol table. - */ - - static inline struct rt_symbol * -lookup_rts(key) - char *key; +static inline struct rt_symbol * +lookup_rts(name, hash) + char *name; + unsigned long hash; { - register int hashval; register struct rt_symbol *rtsp; - /* Determine which bucket. */ - - hashval = hash_string(key) % RTC_TABSIZE; - - /* Search the bucket. */ - - for (rtsp = rt_symtab[hashval]; rtsp; rtsp = rtsp->rt_link) - if (strcmp(key, rtsp->rt_sp->nz_name) == 0) + for (rtsp = rt_symtab[hash % RTC_TABSIZE]; rtsp; rtsp = rtsp->rt_link) + if (strcmp(name, rtsp->rt_sp->nz_name) == 0) return rtsp; return NULL; } - static struct rt_symbol * -enter_rts(name, value, type, srcaddr, size, smp) +/* + * Enter a symbol into the run-time common symbol table. For efficiency, + * the symbol's hash value must be passed in too. + */ +static struct rt_symbol * +enter_rts(name, hash, value, type, srcaddr, size, smp) char *name; - long value; - int type; - caddr_t srcaddr; - long size; + unsigned long hash; + long value; + int type; + caddr_t srcaddr; + long size; struct so_map *smp; { - register int hashval; register struct rt_symbol *rtsp, **rpp; - /* Determine which bucket */ - hashval = hash_string(name) % RTC_TABSIZE; - /* Find end of bucket */ - for (rpp = &rt_symtab[hashval]; *rpp; rpp = &(*rpp)->rt_link) + for (rpp = &rt_symtab[hash % RTC_TABSIZE]; *rpp; rpp = &(*rpp)->rt_link) continue; /* Allocate new common symbol */ - rtsp = (struct rt_symbol *)malloc(sizeof(struct rt_symbol)); - rtsp->rt_sp = (struct nzlist *)malloc(sizeof(struct nzlist)); + rtsp = (struct rt_symbol *)xmalloc(sizeof(struct rt_symbol)); + rtsp->rt_sp = (struct nzlist *)xmalloc(sizeof(struct nzlist)); rtsp->rt_sp->nz_name = strdup(name); rtsp->rt_sp->nz_value = value; rtsp->rt_sp->nz_type = type; @@ -1412,140 +1407,193 @@ enter_rts(name, value, type, srcaddr, size, smp) /* * Lookup NAME in the link maps. The link map producing a definition - * is returned in SRC_MAP. If SRC_MAP is not NULL on entry the search is - * confined to that map. If STRONG is set, the symbol returned must - * have a proper type (used by binder()). + * is returned in SRC_MAP. If SRC_MAP is not NULL on entry the search + * is confined to that map. + * + * REAL_DEF_ONLY is a boolean which specifies whether certain special + * symbols for functions should satisfy the lookup or not. The + * reasons behind it are somewhat complicated. They are motivated + * by the scenario in which the address of a single function is + * taken from several shared objects. The address should come out + * the same in all cases, because the application code might decide + * to use it in comparisons. To make this work, the linker creates + * a symbol entry for the function in the main executable, with a + * type of N_UNDF+N_EXT, an N_AUX of AUX_FUNC, and a value that + * refers to the PLT entry for the function in the main executable. + * If REAL_DEF_ONLY is false, then this kind of special symbol is + * considered a "definition" when lookup up the symbol. Since the + * main executable is at the beginning of the shared object search + * list, the result is that references from all shared objects will + * resolve to the main program's PLT entry, and thus the function + * addresses will compare equal as they should. + * + * When relocating the PLT entry itself, we obviously must match + * only the true defining symbol for the function. In that case, we + * set REAL_DEF_ONLY to true, which disables matching the special + * N_UNDF+N_EXT entries. + * + * It is not so clear how to set this flag for a lookup done from + * dlsym. If the lookup specifies a particular shared object other + * than the main executable, the flag makes no difference -- only the + * true definition will be matched. (That is because the special + * symbols are only present in the main executable, which will not + * be searched.) But when the lookup is over all the shared objects + * (i.e., dlsym's "fd" parameter is NULL), then the flag does have an + * effect. We elect to match only the true definition even in that + * case. + * + * The upshot of all this is the following rule of thumb: Set + * REAL_DEF_ONLY in all cases except when processing a non-PLT + * relocation. */ - static struct nzlist * -lookup(name, src_map, strong) +static struct nzlist * +lookup(name, src_map, real_def_only) char *name; struct so_map **src_map; /* IN/OUT */ - int strong; + int real_def_only; { - long common_size = 0; - struct so_map *smp; - struct rt_symbol *rtsp; + unsigned long hash; - if ((rtsp = lookup_rts(name)) != NULL) - return rtsp->rt_sp; + hash = sym_hash(name); - /* - * Search all maps for a definition of NAME - */ - for (smp = link_map_head; smp; smp = smp->som_next) { - int buckets; - long hashval; - struct rrs_hash *hp; - char *cp; - struct nzlist *np; - - /* Some local caching */ - long symbolbase; - struct rrs_hash *hashbase; - char *stringbase; - int symsize; - - if (*src_map && smp != *src_map) - continue; + if (*src_map != NULL) /* Look in just one specific object */ + return lookup_in_obj(name, hash, *src_map, real_def_only); + else { /* Search runtime symbols and all loaded objects */ + unsigned long common_size; + struct so_map *smp; + struct rt_symbol *rtsp; + struct nzlist *np; - if ((buckets = LD_BUCKETS(smp->som_dynamic)) == 0) - continue; - - if (LM_PRIVATE(smp)->spd_flags & RTLD_RTLD) - continue; + if ((rtsp = lookup_rts(name, hash)) != NULL) + return rtsp->rt_sp; -restart: - /* - * Compute bucket in which the symbol might be found. - */ - for (hashval = 0, cp = name; *cp; cp++) - hashval = (hashval << 1) + *cp; - - hashval = (hashval & 0x7fffffff) % buckets; - - hashbase = LM_HASH(smp); - hp = hashbase + hashval; - if (hp->rh_symbolnum == -1) - /* Nothing in this bucket */ - continue; - - symbolbase = (long)LM_SYMBOL(smp, 0); - stringbase = LM_STRINGS(smp); - symsize = LD_VERSION_NZLIST_P(smp->som_dynamic->d_version)? - sizeof(struct nzlist) : - sizeof(struct nlist); - while (hp) { - np = (struct nzlist *) - (symbolbase + hp->rh_symbolnum * symsize); - cp = stringbase + np->nz_strx; - if (strcmp(cp, name) == 0) - break; - if (hp->rh_next == 0) - hp = NULL; - else - hp = hashbase + hp->rh_next; - } - if (hp == NULL) - /* Nothing in this bucket */ - continue; - - /* - * We have a symbol with the name we're looking for. - */ - if (np->nz_type == N_INDR+N_EXT) { - /* - * Next symbol gives the aliased name. Restart - * search with new name and confine to this map. - */ - name = stringbase + (++np)->nz_strx; - *src_map = smp; - goto restart; - } - - if (np->nz_value == 0) - /* It's not a definition */ - continue; - - if (np->nz_type == N_UNDF+N_EXT && np->nz_value != 0) { - if (np->nz_other == AUX_FUNC) { - /* It's a weak function definition */ - if (strong) - continue; - } else { - /* It's a common, note value and continue search */ + common_size = 0; + for (smp = link_map_head; smp; smp = smp->som_next) { + if (LM_PRIVATE(smp)->spd_flags & RTLD_RTLD) + continue; + np = lookup_in_obj(name, hash, smp, real_def_only); + if (np == NULL) + continue; + /* We know that np->nz_value > 0 at this point. */ + if (np->nz_type == N_UNDF+N_EXT && + N_AUX(&np->nlist) != AUX_FUNC) { /* Common */ if (common_size < np->nz_value) common_size = np->nz_value; continue; } + + /* We found the symbol definition. */ + *src_map = smp; + return np; } + if (common_size > 0) { /* It is a common symbol. */ + void *mem; - *src_map = smp; - return np; + mem = memset(xmalloc(common_size), 0, common_size); + rtsp = enter_rts(name, hash, (long)mem, N_UNDF + N_EXT, + 0, common_size, NULL); + return rtsp->rt_sp; + } + + /* No definition was found for the symbol. */ + return NULL; } +} - if (common_size == 0) - /* Not found */ +/* + * Lookup a symbol in one specific shared object. The hash + * value is passed in for efficiency. For an explanation of the + * "real_def_only" flag, see the comment preceding the "lookup" + * function. + */ +static struct nzlist * +lookup_in_obj(name, hash, smp, real_def_only) + char *name; + unsigned long hash; + struct so_map *smp; + int real_def_only; +{ + unsigned long buckets; + struct rrs_hash *hp; + char *cp; + struct nzlist *np; + char *symbolbase; + struct rrs_hash *hashbase; + char *stringbase; + size_t symsize; + + if ((buckets = LD_BUCKETS(smp->som_dynamic)) == 0) + return NULL; + + hashbase = LM_HASH(smp); + +restart: + hp = &hashbase[hash % buckets]; + if (hp->rh_symbolnum == -1) return NULL; + symbolbase = (char *)LM_SYMBOL(smp, 0); + stringbase = LM_STRINGS(smp); + symsize = LD_VERSION_NZLIST_P(smp->som_dynamic->d_version)? + sizeof(struct nzlist) : sizeof(struct nlist); + for ( ; ; ) { + np = (struct nzlist *)(symbolbase + hp->rh_symbolnum*symsize); + cp = stringbase + np->nz_strx; + if (strcmp(cp, name) == 0) + break; + if (hp->rh_next == 0) /* End of hash chain */ + return NULL; + hp = hashbase + hp->rh_next; + } + /* - * It's a common, enter into run-time common symbol table. + * We have a symbol with the name we're looking for. */ - rtsp = enter_rts(name, (long)calloc(1, common_size), - N_UNDF + N_EXT, 0, common_size, NULL); + if (np->nz_type == N_INDR+N_EXT) { + /* + * Next symbol gives the aliased name. Restart + * search with new name. + */ + name = stringbase + (++np)->nz_strx; + hash = sym_hash(name); + goto restart; + } -#if DEBUG - xprintf("Allocating common: %s size %d at %#x\n", name, common_size, - rtsp->rt_sp->nz_value); -#endif + if (np->nz_value == 0) /* It's not a definition */ + return NULL; + + if (real_def_only) /* Don't match special function symbols. */ + if (np->nz_type == N_UNDF+N_EXT && + N_AUX(&np->nlist) == AUX_FUNC) + return NULL; + + return np; +} - return rtsp->rt_sp; +/* + * Return the value of a symbol in the user's program. This is used + * internally for a few symbols which must exist. If the requested + * symbol is not found, this simply exits with a fatal error. + */ +static void * +sym_addr(name) + char *name; +{ + struct so_map *smp; + struct nzlist *np; + + smp = NULL; + np = lookup(name, &smp, 1); + if (np == NULL) + errx(1, "Program has no symbol \"%s\"", name); + return ((smp == NULL) ? NULL : smp->som_addr) + np->nz_value; } /* * This routine is called from the jumptable to resolve * procedure calls to shared objects. */ - long +long binder(jsp) jmpslot_t *jsp; { @@ -1565,7 +1613,7 @@ binder(jsp) } if (smp == NULL) - errx(1, "Call to binder from unknown location: %#x\n", jsp); + errx(1, "Call to binder from unknown location: %p\n", jsp); index = jsp->reloc_index & JMPSLOT_RELOC_MASK; @@ -1575,7 +1623,7 @@ binder(jsp) np = lookup(sym, &src_map, 1); if (np == NULL) - errx(1, "Undefined symbol \"%s\" called from %s:%s at %#x", + errx(1, "Undefined symbol \"%s\" called from %s:%s at %p", sym, main_progname, smp->som_path, jsp); /* Fixup jmpslot so future calls transfer directly to target */ @@ -1600,7 +1648,7 @@ static char *hstrtab; * Map the hints file into memory, if it is not already mapped. Returns * 0 on success, or -1 on failure. */ - static int +static int maphints __P((void)) { static int hints_bad; /* TRUE if hints are unusable */ @@ -1657,7 +1705,7 @@ maphints __P((void)) /* * Unmap the hints file, if it is currently mapped. */ - static void +static void unmaphints() { if (hheader != NULL) { @@ -1666,7 +1714,7 @@ unmaphints() } } - int +int hinthash(cp, vmajor) char *cp; int vmajor; @@ -1694,7 +1742,7 @@ hinthash(cp, vmajor) * * Returns NULL if the library cannot be found. */ - static char * +static char * findhint(name, major, minorp) char *name; int major; @@ -1748,7 +1796,7 @@ findhint(name, major, minorp) * * Returns NULL if the library cannot be found. */ - static char * +static char * rtfindlib(name, major, minor) char *name; int major, minor; @@ -1794,7 +1842,7 @@ rtfindlib(name, major, minor) * * Returns NULL if the library cannot be found. */ - static char * +static char * rtfindfile(name) char *name; { @@ -1839,10 +1887,10 @@ static char dlerror_buf [DLERROR_BUF_SIZE]; static char *dlerror_msg = NULL; - static void * +static void * __dlopen(path, mode) - char *path; - int mode; + const char *path; + int mode; { struct so_map *old_tail = link_map_tail; struct so_map *smp; @@ -1862,8 +1910,9 @@ __dlopen(path, mode) /* Relocate and initialize all newly-mapped objects */ if(link_map_tail != old_tail) { /* We have mapped some new objects */ - if(reloc_and_init(smp, bind_now) == -1) /* Failed */ + if(reloc_dag(smp, bind_now) == -1) /* Failed */ return NULL; + init_dag(smp); } unmaphints(); @@ -1872,7 +1921,7 @@ __dlopen(path, mode) return smp; } - static int +static int __dlclose(fd) void *fd; { @@ -1902,10 +1951,10 @@ __dlclose(fd) * it. It can still be called by old executables that were linked with * old versions of crt0. */ - static void * +static void * __dlsym(fd, sym) - void *fd; - char *sym; + void *fd; + const char *sym; { if (fd == RTLD_NEXT) { generror("RTLD_NEXT not supported by this version of" @@ -1915,7 +1964,7 @@ __dlsym(fd, sym) return __dlsym3(fd, sym, NULL); } - static void * +static void * resolvesym(fd, sym, retaddr) void *fd; char *sym; @@ -1975,11 +2024,11 @@ resolvesym(fd, sym, retaddr) return (void *)addr; } - static void * +static void * __dlsym3(fd, sym, retaddr) - void *fd; - char *sym; - void *retaddr; + void *fd; + const char *sym; + void *retaddr; { void *result; @@ -1993,7 +2042,7 @@ __dlsym3(fd, sym, retaddr) */ if (result == NULL) { /* Prepend an underscore and try again */ - char *newsym = malloc(strlen(sym) + 2); + char *newsym = xmalloc(strlen(sym) + 2); newsym[0] = '_'; strcpy(&newsym[1], sym); @@ -2003,10 +2052,10 @@ __dlsym3(fd, sym, retaddr) return result; } - static char * +static const char * __dlerror __P((void)) { - char *err; + const char *err; err = dlerror_msg; dlerror_msg = NULL; /* Next call will return NULL */ @@ -2014,7 +2063,7 @@ __dlerror __P((void)) return err; } - static void +static void __dlexit __P((void)) { #ifdef DEBUG @@ -2030,7 +2079,7 @@ xprintf("__dlexit called\n"); static void die __P((void)) { - char *msg; + const char *msg; fprintf(stderr, "ld.so failed"); if ((msg = __dlerror()) != NULL) @@ -2146,3 +2195,162 @@ rt_readenv() } } } + +/* + * Malloc implementation for use within the dynamic linker. At first + * we do a simple allocation using sbrk. After the user's program + * has been loaded, we switch to using whatever malloc functions are + * defined there. + */ + +/* Symbols related to the sbrk and brk implementations. */ +#define CURBRK_SYM "curbrk" +#define MINBRK_SYM "minbrk" +#define END_SYM "_end" + +/* Symbols related to malloc. */ +#define FREE_SYM "_free" +#define MALLOC_SYM "_malloc" +#define REALLOC_SYM "_realloc" + +/* Hooks into the implementation of sbrk and brk. */ +extern char *curbrk __asm__(CURBRK_SYM); +extern char *minbrk __asm__(MINBRK_SYM); + +/* Pointers to the user program's malloc functions. */ +static void *(*p_malloc) __P((size_t)); +static void *(*p_realloc) __P((void *, size_t)); +static void (*p_free) __P((void *)); + +/* Upper limit of the memory allocated by our internal malloc. */ +static char *rtld_alloc_lev; + +/* + * Set up the internal malloc so that it will take its memory from the + * main program's sbrk arena. + */ +static void +init_internal_malloc(dp) + struct _dynamic *dp; +{ + struct so_map tmp_map; + struct somap_private map_private; + struct nzlist *np; + + /* + * Before anything calls sbrk or brk, we have to initialize + * its idea of the current break level to the main program's + * "_end" symbol, rather than that of the dynamic linker. In + * order to do that, we need to look up the value of the main + * program's "_end" symbol. We set up a temporary link map + * entry for the main program so that we can do the lookup. + */ + init_link_map(&tmp_map, &map_private, NULL, NULL, NULL, NULL, dp); + np = lookup_in_obj(END_SYM, sym_hash(END_SYM), &tmp_map, 1); + if (np == NULL) + errx(1, "Main program has no symbol \"%s\"", END_SYM); + rtld_alloc_lev = curbrk = minbrk = (char *)np->nz_value; +} + +/* + * Set things up so that the dynamic linker can use the program's + * malloc functions. + */ +static void +init_external_malloc __P((void)) +{ + /* + * Patch the program's idea of the current break address to + * what it really is as a result of the allocations we have + * already done. + */ + *(char **)(sym_addr(CURBRK_SYM)) = curbrk; + + /* + * Set up pointers to the program's allocation functions, so + * that we can use them from now on. + */ + p_malloc = (void *(*)(size_t))(sym_addr(MALLOC_SYM)); + p_free = (void (*)(void *))(sym_addr(FREE_SYM)); + p_realloc = (void *(*)(void *, size_t))(sym_addr(REALLOC_SYM)); +} + +void * +malloc(size) + size_t size; +{ + char *p; + + /* If we are far enough along, we can use the system malloc. */ + if (p_malloc != NULL) + return (*p_malloc)(size); + + /* + * Otherwise we use our simple built-in malloc. We get the + * memory from brk() in increments of one page. We store the + * allocated size in the first word, so that realloc can be + * made to work. + */ + if (rtld_alloc_lev == NULL) + errx(1, "Internal error: internal malloc called before" + " being initialized"); + + p = (char *)ALIGN(rtld_alloc_lev); + rtld_alloc_lev = p + sizeof(size_t) + size; + + if (rtld_alloc_lev > curbrk) { /* Get memory from system */ + char *newbrk; + + newbrk = (char *) + roundup2((unsigned long)rtld_alloc_lev, PAGSIZ); + if (brk(newbrk) == (char *)-1) + return NULL; + } + + *(size_t *)p = size; + return p + sizeof(size_t); +} + +void * +realloc(ptr, size) + void *ptr; + size_t size; +{ + size_t old_size; + void *new_ptr; + + if (ptr == NULL) + return malloc(size); + + /* + * If we are far enough along, and if the memory originally came + * from the system malloc, we can use the system realloc. + */ + if (p_realloc != NULL && (char *)ptr >= rtld_alloc_lev) + return (*p_realloc)(ptr, size); + + old_size = *((size_t *)ptr - 1); + if (old_size >= size) /* Not expanding the region */ + return ptr; + + new_ptr = malloc(size); + if (new_ptr != NULL) + memcpy(new_ptr, ptr, old_size); + return new_ptr; +} + +void +free(ptr) + void *ptr; +{ + if (ptr == NULL) + return; + + /* + * If we are far enough along, and if the memory originally came + * from the system malloc, we can use the system free. Otherwise + * we can't free the memory and we just let it go to waste. + */ + if (p_free != NULL && (char *)ptr >= rtld_alloc_lev) + (*p_free)(ptr); +} |
