#include "pthread_impl.h"
#include "libc.h"
#include "dynlink.h"
+#include "malloc_impl.h"
static void error(const char *, ...);
Phdr *phdr;
int phnum;
size_t phentsize;
- int refcnt;
Sym *syms;
Elf_Symndx *hashtab;
uint32_t *ghashtab;
int16_t *versym;
char *strings;
+ struct dso *syms_next, *lazy_next;
+ size_t *lazy, lazy_cnt;
unsigned char *map;
size_t map_len;
dev_t dev;
ino_t ino;
- signed char global;
char relocated;
char constructed;
char kernel_mapped;
struct tls_module tls;
size_t tls_id;
size_t relro_start, relro_end;
- void **new_dtv;
+ uintptr_t *new_dtv;
unsigned char *new_tls;
volatile int new_dtv_idx, new_tls_idx;
struct td_index *td_index;
struct dso *dso;
};
-int __init_tp(void *);
-void __init_libc(char **, char *);
-void *__copy_tls(unsigned char *);
-
-__attribute__((__visibility__("hidden")))
-const char *__libc_get_version(void);
-
static struct builtin_tls {
char c;
struct pthread pt;
static size_t *saved_addends, *apply_addends_to;
static struct dso ldso;
-static struct dso *head, *tail, *fini_head;
+static struct dso *head, *tail, *fini_head, *syms_tail, *lazy_head;
static char *env_path, *sys_path;
static unsigned long long gencnt;
static int runtime;
static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
static struct fdpic_loadmap *app_loadmap;
static struct fdpic_dummy_loadmap app_dummy_loadmap;
+static struct dso *const nodeps_dummy;
struct debug *_dl_debug_addr = &debug;
-__attribute__((__visibility__("hidden")))
-void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
+extern hidden int __malloc_replaced;
+
+hidden void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
-__attribute__((__visibility__("hidden")))
-extern void (*const __init_array_end)(void), (*const __fini_array_end)(void);
+extern hidden void (*const __init_array_end)(void), (*const __fini_array_end)(void);
weak_alias(__init_array_start, __init_array_end);
weak_alias(__fini_array_start, __fini_array_end);
for (j=0; v-p->loadmap->segs[j].p_vaddr >= p->loadmap->segs[j].p_memsz; j++);
return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
}
+static void *laddr_pg(const struct dso *p, size_t v)
+{
+ size_t j=0;
+ size_t pgsz = PAGE_SIZE;
+ if (!p->loadmap) return p->base + v;
+ for (j=0; ; j++) {
+ size_t a = p->loadmap->segs[j].p_vaddr;
+ size_t b = a + p->loadmap->segs[j].p_memsz;
+ a &= -pgsz;
+ b += pgsz-1;
+ b &= -pgsz;
+ if (v-a<b-a) break;
+ }
+ return (void *)(v - p->loadmap->segs[j].p_vaddr + p->loadmap->segs[j].addr);
+}
#define fpaddr(p, v) ((void (*)())&(struct funcdesc){ \
laddr(p, v), (p)->got })
#else
#define laddr(p, v) (void *)((p)->base + (v))
+#define laddr_pg(p, v) laddr(p, v)
#define fpaddr(p, v) ((void (*)())laddr(p, v))
#endif
static struct symdef find_sym(struct dso *dso, const char *s, int need_def)
{
- uint32_t h = 0, gh, gho, *ght;
- size_t ghm = 0;
+ uint32_t h = 0, gh = gnu_hash(s), gho = gh / (8*sizeof(size_t)), *ght;
+ size_t ghm = 1ul << gh % (8*sizeof(size_t));
struct symdef def = {0};
- for (; dso; dso=dso->next) {
+ for (; dso; dso=dso->syms_next) {
Sym *sym;
- if (!dso->global) continue;
if ((ght = dso->ghashtab)) {
- if (!ghm) {
- gh = gnu_hash(s);
- int maskbits = 8 * sizeof ghm;
- gho = gh / maskbits;
- ghm = 1ul << gh % maskbits;
- }
sym = gnu_lookup_filtered(gh, ght, dso, s, gho, ghm);
} else {
if (!h) h = sysv_hash(s);
continue;
if (!(1<<(sym->st_info&0xf) & OK_TYPES)) continue;
if (!(1<<(sym->st_info>>4) & OK_BINDS)) continue;
-
- if (def.sym && sym->st_info>>4 == STB_WEAK) continue;
def.sym = sym;
def.dso = dso;
- if (sym->st_info>>4 == STB_GLOBAL) break;
+ break;
}
return def;
}
-__attribute__((__visibility__("hidden")))
-ptrdiff_t __tlsdesc_static(), __tlsdesc_dynamic();
-
static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stride)
{
unsigned char *base = dso->base;
if (skip_relative && IS_RELATIVE(rel[1], dso->syms)) continue;
type = R_TYPE(rel[1]);
if (type == REL_NONE) continue;
- sym_index = R_SYM(rel[1]);
reloc_addr = laddr(dso, rel[0]);
+
+ if (stride > 2) {
+ addend = rel[2];
+ } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
+ addend = 0;
+ } else if (reuse_addends) {
+ /* Save original addend in stage 2 where the dso
+ * chain consists of just ldso; otherwise read back
+ * saved addend since the inline one was clobbered. */
+ if (head==&ldso)
+ saved_addends[save_slot] = *reloc_addr;
+ addend = saved_addends[save_slot++];
+ } else {
+ addend = *reloc_addr;
+ }
+
+ sym_index = R_SYM(rel[1]);
if (sym_index) {
sym = syms + sym_index;
name = strings + sym->st_name;
- ctx = type==REL_COPY ? head->next : head;
+ ctx = type==REL_COPY ? head->syms_next : head;
def = (sym->st_info&0xf) == STT_SECTION
? (struct symdef){ .dso = dso, .sym = sym }
: find_sym(ctx, name, type==REL_PLT);
if (!def.sym && (sym->st_shndx != SHN_UNDEF
|| sym->st_info>>4 != STB_WEAK)) {
+ if (dso->lazy && (type==REL_PLT || type==REL_GOT)) {
+ dso->lazy[3*dso->lazy_cnt+0] = rel[0];
+ dso->lazy[3*dso->lazy_cnt+1] = rel[1];
+ dso->lazy[3*dso->lazy_cnt+2] = addend;
+ dso->lazy_cnt++;
+ continue;
+ }
error("Error relocating %s: %s: symbol not found",
dso->name, name);
if (runtime) longjmp(*rtld_fail, 1);
def.dso = dso;
}
- if (stride > 2) {
- addend = rel[2];
- } else if (type==REL_GOT || type==REL_PLT|| type==REL_COPY) {
- addend = 0;
- } else if (reuse_addends) {
- /* Save original addend in stage 2 where the dso
- * chain consists of just ldso; otherwise read back
- * saved addend since the inline one was clobbered. */
- if (head==&ldso)
- saved_addends[save_slot] = *reloc_addr;
- addend = saved_addends[save_slot++];
- } else {
- addend = *reloc_addr;
- }
-
sym_val = def.sym ? (size_t)laddr(def.dso, def.sym->st_value) : 0;
tls_val = def.sym ? def.sym->st_value : 0;
+ if ((type == REL_TPOFF || type == REL_TPOFF_NEG)
+ && runtime && def.dso->tls_id > static_tls_cnt) {
+ error("Error relocating %s: %s: initial-exec TLS "
+ "resolves to dynamic definition in %s",
+ dso->name, name, def.dso->name);
+ longjmp(*rtld_fail, 1);
+ }
+
switch(type) {
case REL_NONE:
break;
#endif
case REL_TLSDESC:
if (stride<3) addend = reloc_addr[1];
- if (runtime && def.dso->tls_id >= static_tls_cnt) {
+ if (runtime && def.dso->tls_id > static_tls_cnt) {
struct td_index *new = malloc(sizeof *new);
if (!new) {
error(
new->next = dso->td_index;
dso->td_index = new;
new->args[0] = def.dso->tls_id;
- new->args[1] = tls_val + addend;
+ new->args[1] = tls_val + addend - DTP_OFFSET;
reloc_addr[0] = (size_t)__tlsdesc_dynamic;
reloc_addr[1] = (size_t)new;
} else {
+ addend;
#endif
}
+#ifdef TLSDESC_BACKWARDS
+ /* Some archs (32-bit ARM at least) invert the order of
+ * the descriptor members. Fix them up here. */
+ size_t tmp = reloc_addr[0];
+ reloc_addr[0] = reloc_addr[1];
+ reloc_addr[1] = tmp;
+#endif
break;
default:
error("Error relocating %s: unsupported relocation type %d",
}
}
+static void redo_lazy_relocs()
+{
+ struct dso *p = lazy_head, *next;
+ lazy_head = 0;
+ for (; p; p=next) {
+ next = p->lazy_next;
+ size_t size = p->lazy_cnt*3*sizeof(size_t);
+ p->lazy_cnt = 0;
+ do_relocs(p, p->lazy, size, 3);
+ if (p->lazy_cnt) {
+ p->lazy_next = lazy_head;
+ lazy_head = p;
+ } else {
+ free(p->lazy);
+ p->lazy = 0;
+ p->lazy_next = 0;
+ }
+ }
+}
+
/* A huge hack: to make up for the wastefulness of shared libraries
* needing at least a page of dirty memory even if they have no global
* data, we reclaim the gaps at the beginning and end of writable maps
- * and "donate" them to the heap by setting up minimal malloc
- * structures and then freeing them. */
+ * and "donate" them to the heap. */
static void reclaim(struct dso *dso, size_t start, size_t end)
{
- size_t *a, *z;
if (start >= dso->relro_start && start < dso->relro_end) start = dso->relro_end;
if (end >= dso->relro_start && end < dso->relro_end) end = dso->relro_start;
- start = start + 6*sizeof(size_t)-1 & -4*sizeof(size_t);
- end = (end & -4*sizeof(size_t)) - 2*sizeof(size_t);
- if (start>end || end-start < 4*sizeof(size_t)) return;
- a = laddr(dso, start);
- z = laddr(dso, end);
- a[-2] = 1;
- a[-1] = z[0] = end-start + 2*sizeof(size_t) | 1;
- z[1] = 1;
- free(a);
+ if (start >= end) return;
+ char *base = laddr_pg(dso, start);
+ __malloc_donate(base, base+(end-start));
}
static void reclaim_gaps(struct dso *dso)
Phdr *ph = dso->phdr;
size_t phcnt = dso->phnum;
- if (DL_FDPIC) return; // FIXME
for (; phcnt--; ph=(void *)((char *)ph+dso->phentsize)) {
if (ph->p_type!=PT_LOAD) continue;
if ((ph->p_flags&(PF_R|PF_W))!=(PF_R|PF_W)) continue;
} else if (ph->p_type == PT_GNU_RELRO) {
dso->relro_start = ph->p_vaddr & -PAGE_SIZE;
dso->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
+ } else if (ph->p_type == PT_GNU_STACK) {
+ if (!runtime && ph->p_memsz > __default_stacksize) {
+ __default_stacksize =
+ ph->p_memsz < DEFAULT_STACK_MAX ?
+ ph->p_memsz : DEFAULT_STACK_MAX;
+ }
}
if (ph->p_type != PT_LOAD) continue;
nsegs++;
dso->phnum = eh->e_phnum;
dso->phentsize = eh->e_phentsize;
}
- /* Reuse the existing mapping for the lowest-address LOAD */
- if ((ph->p_vaddr & -PAGE_SIZE) == addr_min && !DL_NOMMU_SUPPORT)
- continue;
this_min = ph->p_vaddr & -PAGE_SIZE;
this_max = ph->p_vaddr+ph->p_memsz+PAGE_SIZE-1 & -PAGE_SIZE;
off_start = ph->p_offset & -PAGE_SIZE;
prot = (((ph->p_flags&PF_R) ? PROT_READ : 0) |
((ph->p_flags&PF_W) ? PROT_WRITE: 0) |
((ph->p_flags&PF_X) ? PROT_EXEC : 0));
- if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
- goto error;
- if (ph->p_memsz > ph->p_filesz) {
+ /* Reuse the existing mapping for the lowest-address LOAD */
+ if ((ph->p_vaddr & -PAGE_SIZE) != addr_min || DL_NOMMU_SUPPORT)
+ if (mmap_fixed(base+this_min, this_max-this_min, prot, MAP_PRIVATE|MAP_FIXED, fd, off_start) == MAP_FAILED)
+ goto error;
+ if (ph->p_memsz > ph->p_filesz && (ph->p_flags&PF_W)) {
size_t brk = (size_t)base+ph->p_vaddr+ph->p_filesz;
size_t pgbrk = brk+PAGE_SIZE-1 & -PAGE_SIZE;
memset((void *)brk, 0, pgbrk-brk & PAGE_SIZE-1);
dso->base = base;
dso->dynv = laddr(dso, dyn);
if (dso->tls.size) dso->tls.image = laddr(dso, tls_image);
- if (!runtime) reclaim_gaps(dso);
free(allocated_buf);
return map;
noexec:
origin = p->name;
}
t = strrchr(origin, '/');
- l = t ? t-origin : 0;
+ if (t) {
+ l = t-origin;
+ } else {
+ /* Normally p->name will always be an absolute or relative
+ * pathname containing at least one '/' character, but in the
+ * case where ldso was invoked as a command to execute a
+ * program in the working directory, app.name may not. Fix. */
+ origin = ".";
+ l = 1;
+ }
+ /* Disallow non-absolute origins for suid/sgid/AT_SECURE. */
+ if (libc.secure && *origin != '/')
+ return 0;
p->rpath = malloc(strlen(p->rpath_orig) + n*l + 1);
if (!p->rpath) return -1;
if (!ldso.prev) {
tail->next = &ldso;
ldso.prev = tail;
- tail = ldso.next ? ldso.next : &ldso;
+ tail = &ldso;
}
return &ldso;
}
/* Search for the name to see if it's already loaded */
for (p=head->next; p; p=p->next) {
if (p->shortname && !strcmp(p->shortname, name)) {
- p->refcnt++;
return p;
}
}
if (!p->shortname && pathname != name)
p->shortname = strrchr(p->name, '/')+1;
close(fd);
- p->refcnt++;
return p;
}
}
close(fd);
if (!map) return 0;
+ /* Avoid the danger of getting two versions of libc mapped into the
+ * same process when an absolute pathname was used. The symbols
+ * checked are chosen to catch both musl and glibc, and to avoid
+ * false positives from interposition-hack libraries. */
+ decode_dyn(&temp_dso);
+ if (find_sym(&temp_dso, "__libc_start_main", 1).sym &&
+ find_sym(&temp_dso, "stdin", 1).sym) {
+ unmap_library(&temp_dso);
+ return load_library("libc.so", needed_by);
+ }
+ /* Past this point, if we haven't reached runtime yet, ldso has
+ * committed either to use the mapped library or to abort execution.
+ * Unmapping is not possible, so we can safely reclaim gaps. */
+ if (!runtime) reclaim_gaps(&temp_dso);
+
/* Allocate storage for the new DSO. When there is TLS, this
* storage must include a reservation for all pre-existing
* threads to obtain copies of both the new TLS, and an
return 0;
}
memcpy(p, &temp_dso, sizeof temp_dso);
- decode_dyn(p);
p->dev = st.st_dev;
p->ino = st.st_ino;
- p->refcnt = 1;
p->needed_by = needed_by;
p->name = p->buf;
strcpy(p->name, pathname);
}
}
}
+ if (!*deps) *deps = (struct dso **)&nodeps_dummy;
}
static void load_preload(char *s)
}
}
-static void make_global(struct dso *p)
+static void add_syms(struct dso *p)
{
- for (; p; p=p->next) p->global = 1;
+ if (!p->syms_next && syms_tail != p) {
+ syms_tail->syms_next = p;
+ syms_tail = p;
+ }
+}
+
+static void revert_syms(struct dso *old_tail)
+{
+ struct dso *p, *next;
+ /* Chop off the tail of the list of dsos that participate in
+ * the global symbol table, reverting them to RTLD_LOCAL. */
+ for (p=old_tail; p; p=next) {
+ next = p->syms_next;
+ p->syms_next = 0;
+ }
+ syms_tail = old_tail;
}
static void do_mips_relocs(struct dso *p, size_t *got)
} else if (ph->p_type == PT_GNU_RELRO) {
p->relro_start = ph->p_vaddr & -PAGE_SIZE;
p->relro_end = (ph->p_vaddr + ph->p_memsz) & -PAGE_SIZE;
+ } else if (ph->p_type == PT_GNU_STACK) {
+ if (!runtime && ph->p_memsz > __default_stacksize) {
+ __default_stacksize =
+ ph->p_memsz < DEFAULT_STACK_MAX ?
+ ph->p_memsz : DEFAULT_STACK_MAX;
+ }
}
if (ph->p_type != PT_LOAD) continue;
if (ph->p_vaddr < min_addr)
{
}
-__attribute__((__visibility__("hidden")))
-void *__tls_get_new(size_t *v)
+hidden void *__tls_get_new(tls_mod_off_t *v)
{
pthread_t self = __pthread_self();
/* Block signals to make accessing new TLS async-signal-safe */
sigset_t set;
__block_all_sigs(&set);
- if (v[0]<=(size_t)self->dtv[0]) {
+ if (v[0] <= self->dtv[0]) {
__restore_sigs(&set);
- return (char *)self->dtv[v[0]]+v[1]+DTP_OFFSET;
+ return (void *)(self->dtv[v[0]] + v[1]);
}
/* This is safe without any locks held because, if the caller
struct dso *p;
for (p=head; p->tls_id != v[0]; p=p->next);
- /* Get new DTV space from new DSO if needed */
- if (v[0] > (size_t)self->dtv[0]) {
- void **newdtv = p->new_dtv +
- (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
- memcpy(newdtv, self->dtv,
- ((size_t)self->dtv[0]+1) * sizeof(void *));
- newdtv[0] = (void *)v[0];
- self->dtv = self->dtv_copy = newdtv;
- }
+ /* Get new DTV space from new DSO */
+ uintptr_t *newdtv = p->new_dtv +
+ (v[0]+1)*a_fetch_add(&p->new_dtv_idx,1);
+ memcpy(newdtv, self->dtv, (self->dtv[0]+1) * sizeof(uintptr_t));
+ newdtv[0] = v[0];
+ self->dtv = self->dtv_copy = newdtv;
/* Get new TLS memory from all new DSOs up to the requested one */
unsigned char *mem;
* a_fetch_add(&p->new_tls_idx,1);
mem += ((uintptr_t)p->tls.image - (uintptr_t)mem)
& (p->tls.align-1);
- self->dtv[p->tls_id] = mem;
+ self->dtv[p->tls_id] = (uintptr_t)mem + DTP_OFFSET;
memcpy(mem, p->tls.image, p->tls.len);
if (p->tls_id == v[0]) break;
}
* linker itself, but some of the relocations performed may need to be
* replaced later due to copy relocations in the main program. */
-__attribute__((__visibility__("hidden")))
-void __dls2(unsigned char *base, size_t *sp)
+hidden void __dls2(unsigned char *base, size_t *sp)
{
if (DL_FDPIC) {
void *p1 = (void *)sp[-2];
void *p2 = (void *)sp[-1];
if (!p1) {
size_t *auxv, aux[AUX_CNT];
- for (auxv=sp+1+*sp+1; *auxv; auxv++); auxv++;
+ for (auxv=sp+1+*sp+1; *auxv; auxv++);
+ auxv++;
decode_vec(auxv, aux, AUX_CNT);
if (aux[AT_BASE]) ldso.base = (void *)aux[AT_BASE];
else ldso.base = (void *)(aux[AT_PHDR] & -4096);
}
Ehdr *ehdr = (void *)ldso.base;
ldso.name = ldso.shortname = "libc.so";
- ldso.global = 1;
ldso.phnum = ehdr->e_phnum;
ldso.phdr = laddr(&ldso, ehdr->e_phoff);
ldso.phentsize = ehdr->e_phentsize;
ldso.relocated = 0;
- /* Call dynamic linker stage-3, __dls3, looking it up
+ /* Call dynamic linker stage-2b, __dls2b, looking it up
* symbolically as a barrier against moving the address
* load across the above relocation processing. */
+ struct symdef dls2b_def = find_sym(&ldso, "__dls2b", 0);
+ if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls2b_def.sym-ldso.syms])(sp);
+ else ((stage3_func)laddr(&ldso, dls2b_def.sym->st_value))(sp);
+}
+
+/* Stage 2b sets up a valid thread pointer, which requires relocations
+ * completed in stage 2, and on which stage 3 is permitted to depend.
+ * This is done as a separate stage, with symbolic lookup as a barrier,
+ * so that loads of the thread pointer and &errno can be pure/const and
+ * thereby hoistable. */
+
+_Noreturn void __dls2b(size_t *sp)
+{
+ /* Setup early thread pointer in builtin_tls for ldso/libc itself to
+ * use during dynamic linking. If possible it will also serve as the
+ * thread pointer at runtime. */
+ libc.tls_size = sizeof builtin_tls;
+ libc.tls_align = tls_align;
+ if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
+ a_crash();
+ }
+
struct symdef dls3_def = find_sym(&ldso, "__dls3", 0);
if (DL_FDPIC) ((stage3_func)&ldso.funcdescs[dls3_def.sym-ldso.syms])(sp);
else ((stage3_func)laddr(&ldso, dls3_def.sym->st_value))(sp);
size_t aux[AUX_CNT], *auxv;
size_t i;
char *env_preload=0;
+ char *replace_argv0=0;
size_t vdso_base;
int argc = *sp;
char **argv = (void *)(sp+1);
libc.secure = ((aux[0]&0x7800)!=0x7800 || aux[AT_UID]!=aux[AT_EUID]
|| aux[AT_GID]!=aux[AT_EGID] || aux[AT_SECURE]);
- /* Setup early thread pointer in builtin_tls for ldso/libc itself to
- * use during dynamic linking. If possible it will also serve as the
- * thread pointer at runtime. */
- libc.tls_size = sizeof builtin_tls;
- libc.tls_align = tls_align;
- if (__init_tp(__copy_tls((void *)builtin_tls)) < 0) {
- a_crash();
- }
-
/* Only trust user/env if kernel says we're not suid/sgid */
if (!libc.secure) {
env_path = getenv("LD_LIBRARY_PATH");
if (opt[7]=='=') env_preload = opt+8;
else if (opt[7]) *argv = 0;
else if (*argv) env_preload = *argv++;
+ } else if (!memcmp(opt, "argv0", 5)) {
+ if (opt[5]=='=') replace_argv0 = opt+6;
+ else if (opt[5]) *argv = 0;
+ else if (*argv) replace_argv0 = *argv++;
} else {
argv[0] = 0;
}
"Version %s\n"
"Dynamic Program Loader\n"
"Usage: %s [options] [--] pathname%s\n",
- __libc_get_version(), ldname,
+ __libc_version, ldname,
ldd_mode ? "" : " [args]");
_exit(1);
}
dprintf(2, "%s: cannot load %s: %s\n", ldname, argv[0], strerror(errno));
_exit(1);
}
- runtime = 1;
Ehdr *ehdr = (void *)map_library(fd, &app);
if (!ehdr) {
dprintf(2, "%s: %s: Not a valid dynamic program\n", ldname, argv[0]);
_exit(1);
}
- runtime = 0;
close(fd);
ldso.name = ldname;
app.name = argv[0];
libc.tls_head = tls_tail = &app.tls;
app.tls_id = tls_cnt = 1;
#ifdef TLS_ABOVE_TP
- app.tls.offset = 0;
- tls_offset = app.tls.size
+ app.tls.offset = GAP_ABOVE_TP;
+ app.tls.offset += -GAP_ABOVE_TP & (app.tls.align-1);
+ tls_offset = app.tls.offset + app.tls.size
+ ( -((uintptr_t)app.tls.image + app.tls.size)
& (app.tls.align-1) );
#else
#endif
tls_align = MAXP2(tls_align, app.tls.align);
}
- app.global = 1;
decode_dyn(&app);
if (DL_FDPIC) {
makefuncdescs(&app);
argv[-3] = (void *)app.loadmap;
}
- /* Attach to vdso, if provided by the kernel */
- if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR)) {
+ /* Initial dso chain consists only of the app. */
+ head = tail = syms_tail = &app;
+
+ /* Donate unused parts of app and library mapping to malloc */
+ reclaim_gaps(&app);
+ reclaim_gaps(&ldso);
+
+ /* Load preload/needed libraries, add symbols to global namespace. */
+ if (env_preload) load_preload(env_preload);
+ load_deps(&app);
+ for (struct dso *p=head; p; p=p->next)
+ add_syms(p);
+
+ /* Attach to vdso, if provided by the kernel, last so that it does
+ * not become part of the global namespace. */
+ if (search_vec(auxv, &vdso_base, AT_SYSINFO_EHDR) && vdso_base) {
Ehdr *ehdr = (void *)vdso_base;
Phdr *phdr = vdso.phdr = (void *)(vdso_base + ehdr->e_phoff);
vdso.phnum = ehdr->e_phnum;
}
vdso.name = "";
vdso.shortname = "linux-gate.so.1";
- vdso.global = 1;
vdso.relocated = 1;
decode_dyn(&vdso);
- vdso.prev = &ldso;
- ldso.next = &vdso;
+ vdso.prev = tail;
+ tail->next = &vdso;
+ tail = &vdso;
}
- /* Initial dso chain consists only of the app. */
- head = tail = &app;
-
- /* Donate unused parts of app and library mapping to malloc */
- reclaim_gaps(&app);
- reclaim_gaps(&ldso);
-
- /* Load preload/needed libraries, add their symbols to the global
- * namespace, and perform all remaining relocations. */
- if (env_preload) load_preload(env_preload);
- load_deps(&app);
- make_global(&app);
-
for (i=0; app.dynv[i]; i+=2) {
if (!DT_DEBUG_INDIRECT && app.dynv[i]==DT_DEBUG)
app.dynv[i+1] = (size_t)&debug;
if (ldso_fail) _exit(127);
if (ldd_mode) _exit(0);
+ /* Determine if malloc was interposed by a replacement implementation
+ * so that calloc and the memalign family can harden against the
+ * possibility of incomplete replacement. */
+ if (find_sym(head, "malloc", 1).dso != &ldso)
+ __malloc_replaced = 1;
+
/* Switch to runtime mode: any further failures in the dynamic
* linker are a reportable failure rather than a fatal startup
* error. */
debug.state = 0;
_dl_debug_state();
+ if (replace_argv0) argv[0] = replace_argv0;
+
errno = 0;
CRTJMP((void *)aux[AT_ENTRY], argv-1);
for(;;);
}
+static void prepare_lazy(struct dso *p)
+{
+ size_t dyn[DYN_CNT], n, flags1=0;
+ decode_vec(p->dynv, dyn, DYN_CNT);
+ search_vec(p->dynv, &flags1, DT_FLAGS_1);
+ if (dyn[DT_BIND_NOW] || (dyn[DT_FLAGS] & DF_BIND_NOW) || (flags1 & DF_1_NOW))
+ return;
+ n = dyn[DT_RELSZ]/2 + dyn[DT_RELASZ]/3 + dyn[DT_PLTRELSZ]/2 + 1;
+ if (NEED_MIPS_GOT_RELOCS) {
+ size_t j=0; search_vec(p->dynv, &j, DT_MIPS_GOTSYM);
+ size_t i=0; search_vec(p->dynv, &i, DT_MIPS_SYMTABNO);
+ n += i-j;
+ }
+ p->lazy = calloc(n, 3*sizeof(size_t));
+ if (!p->lazy) {
+ error("Error preparing lazy relocation for %s: %m", p->name);
+ longjmp(*rtld_fail, 1);
+ }
+ p->lazy_next = lazy_head;
+ lazy_head = p;
+}
+
void *dlopen(const char *file, int mode)
{
- struct dso *volatile p, *orig_tail, *next;
+ struct dso *volatile p, *orig_tail, *orig_syms_tail, *orig_lazy_head, *next;
struct tls_module *orig_tls_tail;
size_t orig_tls_cnt, orig_tls_offset, orig_tls_align;
size_t i;
orig_tls_cnt = tls_cnt;
orig_tls_offset = tls_offset;
orig_tls_align = tls_align;
+ orig_lazy_head = lazy_head;
+ orig_syms_tail = syms_tail;
orig_tail = tail;
noload = mode & RTLD_NOLOAD;
rtld_fail = &jb;
if (setjmp(*rtld_fail)) {
/* Clean up anything new that was (partially) loaded */
- if (p && p->deps) for (i=0; p->deps[i]; i++)
- if (p->deps[i]->global < 0)
- p->deps[i]->global = 0;
+ revert_syms(orig_syms_tail);
for (p=orig_tail->next; p; p=next) {
next = p->next;
while (p->td_index) {
free(p->funcdescs);
if (p->rpath != p->rpath_orig)
free(p->rpath);
- free(p->deps);
+ if (p->deps != &nodeps_dummy)
+ free(p->deps);
unmap_library(p);
free(p);
}
if (!orig_tls_tail) libc.tls_head = 0;
tls_tail = orig_tls_tail;
+ if (tls_tail) tls_tail->next = 0;
tls_cnt = orig_tls_cnt;
tls_offset = orig_tls_offset;
tls_align = orig_tls_align;
+ lazy_head = orig_lazy_head;
tail = orig_tail;
tail->next = 0;
p = 0;
}
/* First load handling */
- if (!p->deps) {
+ int first_load = !p->deps;
+ if (first_load) {
load_deps(p);
- if (p->deps) for (i=0; p->deps[i]; i++)
- if (!p->deps[i]->global)
- p->deps[i]->global = -1;
- if (!p->global) p->global = -1;
+ if (!p->relocated && (mode & RTLD_LAZY)) {
+ prepare_lazy(p);
+ for (i=0; p->deps[i]; i++)
+ if (!p->deps[i]->relocated)
+ prepare_lazy(p->deps[i]);
+ }
+ }
+ if (first_load || (mode & RTLD_GLOBAL)) {
+ /* Make new symbols global, at least temporarily, so we can do
+ * relocations. If not RTLD_GLOBAL, this is reverted below. */
+ add_syms(p);
+ for (i=0; p->deps[i]; i++)
+ add_syms(p->deps[i]);
+ }
+ if (first_load) {
reloc_all(p);
- if (p->deps) for (i=0; p->deps[i]; i++)
- if (p->deps[i]->global < 0)
- p->deps[i]->global = 0;
- if (p->global < 0) p->global = 0;
}
- if (mode & RTLD_GLOBAL) {
- if (p->deps) for (i=0; p->deps[i]; i++)
- p->deps[i]->global = 1;
- p->global = 1;
- }
+ /* If RTLD_GLOBAL was not specified, undo any new additions
+ * to the global symbol table. This is a nop if the library was
+ * previously loaded and already global. */
+ if (!(mode & RTLD_GLOBAL))
+ revert_syms(orig_syms_tail);
+
+ /* Processing of deferred lazy relocations must not happen until
+ * the new libraries are committed; otherwise we could end up with
+ * relocations resolved to symbol definitions that get removed. */
+ redo_lazy_relocs();
update_tls_size();
_dl_debug_state();
return p;
}
-__attribute__((__visibility__("hidden")))
-int __dl_invalid_handle(void *h)
+hidden int __dl_invalid_handle(void *h)
{
struct dso *p;
for (p=head; p; p=p->next) if (h==p) return 0;
return p;
}
} else {
+ Phdr *ph = p->phdr;
+ size_t phcnt = p->phnum;
+ size_t entsz = p->phentsize;
+ size_t base = (size_t)p->base;
+ for (; phcnt--; ph=(void *)((char *)ph+entsz)) {
+ if (ph->p_type != PT_LOAD) continue;
+ if (a-base-ph->p_vaddr < ph->p_memsz)
+ return p;
+ }
if (a-(size_t)p->map < p->map_len)
- return p;
+ return 0;
}
}
return 0;
}
-void *__tls_get_addr(size_t *);
-
static void *do_dlsym(struct dso *p, const char *s, void *ra)
{
size_t i;
struct symdef def = find_sym(p, s, 0);
if (!def.sym) goto failed;
if ((def.sym->st_info&0xf) == STT_TLS)
- return __tls_get_addr((size_t []){def.dso->tls_id, def.sym->st_value});
+ return __tls_get_addr((tls_mod_off_t []){def.dso->tls_id, def.sym->st_value-DTP_OFFSET});
if (DL_FDPIC && (def.sym->st_info&0xf) == STT_FUNC)
return def.dso->funcdescs + (def.sym - def.dso->syms);
return laddr(def.dso, def.sym->st_value);
sym = sysv_lookup(s, h, p);
}
if (sym && (sym->st_info&0xf) == STT_TLS)
- return __tls_get_addr((size_t []){p->tls_id, sym->st_value});
+ return __tls_get_addr((tls_mod_off_t []){p->tls_id, sym->st_value-DTP_OFFSET});
if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
return p->funcdescs + (sym - p->syms);
if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
return laddr(p, sym->st_value);
- if (p->deps) for (i=0; p->deps[i]; i++) {
+ for (i=0; p->deps[i]; i++) {
if ((ght = p->deps[i]->ghashtab)) {
if (!gh) gh = gnu_hash(s);
sym = gnu_lookup(gh, ght, p->deps[i], s);
sym = sysv_lookup(s, h, p->deps[i]);
}
if (sym && (sym->st_info&0xf) == STT_TLS)
- return __tls_get_addr((size_t []){p->deps[i]->tls_id, sym->st_value});
+ return __tls_get_addr((tls_mod_off_t []){p->deps[i]->tls_id, sym->st_value-DTP_OFFSET});
if (DL_FDPIC && sym && sym->st_shndx && (sym->st_info&0xf) == STT_FUNC)
return p->deps[i]->funcdescs + (sym - p->deps[i]->syms);
if (sym && sym->st_value && (1<<(sym->st_info&0xf) & OK_TYPES))
return 0;
}
-int dladdr(const void *addr, Dl_info *info)
+int dladdr(const void *addr_arg, Dl_info *info)
{
+ size_t addr = (size_t)addr_arg;
struct dso *p;
Sym *sym, *bestsym;
uint32_t nsym;
char *strings;
- void *best = 0;
+ size_t best = 0;
+ size_t besterr = -1;
pthread_rwlock_rdlock(&lock);
- p = addr2dso((size_t)addr);
+ p = addr2dso(addr);
pthread_rwlock_unlock(&lock);
if (!p) return 0;
nsym = count_syms(p);
if (DL_FDPIC) {
- size_t idx = ((size_t)addr-(size_t)p->funcdescs)
+ size_t idx = (addr-(size_t)p->funcdescs)
/ sizeof(*p->funcdescs);
if (idx < nsym && (sym[idx].st_info&0xf) == STT_FUNC) {
- best = p->funcdescs + idx;
+ best = (size_t)(p->funcdescs + idx);
bestsym = sym + idx;
+ besterr = 0;
}
}
if (sym->st_value
&& (1<<(sym->st_info&0xf) & OK_TYPES)
&& (1<<(sym->st_info>>4) & OK_BINDS)) {
- void *symaddr = laddr(p, sym->st_value);
- if (symaddr > addr || symaddr < best)
+ size_t symaddr = (size_t)laddr(p, sym->st_value);
+ if (symaddr > addr || symaddr <= best)
continue;
best = symaddr;
bestsym = sym;
+ besterr = addr - symaddr;
if (addr == symaddr)
break;
}
}
- if (!best) return 0;
-
- if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
- best = p->funcdescs + (bestsym - p->syms);
+ if (bestsym && besterr > bestsym->st_size-1) {
+ best = 0;
+ bestsym = 0;
+ }
info->dli_fname = p->name;
- info->dli_fbase = p->base;
+ info->dli_fbase = p->map;
+
+ if (!best) {
+ info->dli_sname = 0;
+ info->dli_saddr = 0;
+ return 1;
+ }
+
+ if (DL_FDPIC && (bestsym->st_info&0xf) == STT_FUNC)
+ best = (size_t)(p->funcdescs + (bestsym - p->syms));
info->dli_sname = strings + bestsym->st_name;
- info->dli_saddr = best;
+ info->dli_saddr = (void *)best;
return 1;
}
-__attribute__((__visibility__("hidden")))
-void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
+hidden void *__dlsym(void *restrict p, const char *restrict s, void *restrict ra)
{
void *res;
pthread_rwlock_rdlock(&lock);
return ret;
}
-__attribute__((__visibility__("hidden")))
-void __dl_vseterr(const char *, va_list);
-
static void error(const char *fmt, ...)
{
va_list ap;
projects / musl / blobdiff