diff --git a/src/internal/dynlink.h b/src/internal/dynlink.h
index 53661d6..8621d2d 100644
--- a/src/internal/dynlink.h
+++ b/src/internal/dynlink.h
@@ -51,7 +51,7 @@ enum {
#define AUX_CNT 32
#define DYN_CNT 32
-typedef void (*stage2_func)(unsigned char *);
+typedef void (*stage2_func)(unsigned char *, size_t *);
typedef _Noreturn void (*stage3_func)(size_t *);
#endif
diff --git a/src/ldso/dlstart.c b/src/ldso/dlstart.c
index 5f84465..6af5037 100644
--- a/src/ldso/dlstart.c
+++ b/src/ldso/dlstart.c
@@ -56,12 +56,15 @@ void _dlstart_c(size_t *sp, size_t *dynv)
for (i=0; i<local_cnt; i++) got[i] += (size_t)base;
}
- size_t *rel, rel_size;
+ size_t *rel, rel_size, symbolic_rel_cnt=0;
rel = (void *)(base+dyn[DT_REL]);
rel_size = dyn[DT_RELSZ];
for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t)) {
- if (!IS_RELATIVE(rel[1])) continue;
+ if (!IS_RELATIVE(rel[1])) {
+ symbolic_rel_cnt++;
+ continue;
+ }
size_t *rel_addr = (void *)(base + rel[0]);
*rel_addr += (size_t)base;
}
@@ -74,6 +77,16 @@ void _dlstart_c(size_t *sp, size_t *dynv)
*rel_addr = (size_t)base + rel[2];
}
+ /* Prepare storage for stages 2 to save clobbered REL
+ * addends so they can be reused in stage 3. There should
+ * be very few. If something goes wrong and there are a
+ * huge number, pass a null pointer to trigger stage 2
+ * to abort instead of risking stack overflow. */
+ int too_many_addends = symbolic_rel_cnt > 4096;
+ size_t naddends = too_many_addends ? 1 : symbolic_rel_cnt;
+ size_t addends[naddends];
+ size_t *paddends = too_many_addends ? 0 : addends;
+
const char *strings = (void *)(base + dyn[DT_STRTAB]);
const Sym *syms = (void *)(base + dyn[DT_SYMTAB]);
@@ -84,7 +97,7 @@ void _dlstart_c(size_t *sp, size_t *dynv)
&& s[3]=='l' && s[4]=='s' && s[5]=='2' && !s[6])
break;
}
- ((stage2_func)(base + syms[i].st_value))(base);
+ ((stage2_func)(base + syms[i].st_value))(base, paddends);
/* Call dynamic linker stage-3, __dls3 */
for (i=0; ;i++) {
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 93595a0..bfc1c96 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -74,7 +74,6 @@ struct dso {
volatile int new_dtv_idx, new_tls_idx;
struct td_index *td_index;
struct dso *fini_next;
- int rel_early_relative, rel_update_got;
char *shortname;
char buf[];
};
@@ -98,6 +97,7 @@ static struct builtin_tls {
static struct dso ldso;
static struct dso *head, *tail, *fini_head;
+static size_t *saved_addends;
static char *env_path, *sys_path;
static unsigned long long gencnt;
static int runtime;
@@ -256,9 +256,19 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
size_t sym_val;
size_t tls_val;
size_t addend;
+ int skip_relative = 0, reuse_addends = 0, save_slot = 0;
+
+ if (dso == &ldso) {
+ size_t dyn[DYN_CNT];
+ decode_vec(ldso.dynv, dyn, DYN_CNT);
+ /* Only ldso's REL table needs addend saving/reuse. */
+ if (rel == (size_t *)(ldso.base+dyn[DT_REL]))
+ reuse_addends = 1;
+ skip_relative = 1;
+ }
for (; rel_size; rel+=stride, rel_size-=stride*sizeof(size_t)) {
- if (dso->rel_early_relative && IS_RELATIVE(rel[1])) continue;
+ if (skip_relative && IS_RELATIVE(rel[1])) continue;
type = R_TYPE(rel[1]);
sym_index = R_SYM(rel[1]);
reloc_addr = (void *)(base + rel[0]);
@@ -280,12 +290,20 @@ static void do_relocs(struct dso *dso, size_t *rel, size_t rel_size, size_t stri
def.dso = dso;
}
- int gotplt = (type == REL_GOT || type == REL_PLT);
- if (dso->rel_update_got && !gotplt && stride==2) continue;
-
- addend = stride>2 ? rel[2]
- : gotplt || type==REL_COPY ? 0
- : *reloc_addr;
+ 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)def.dso->base+def.sym->st_value : 0;
tls_val = def.sym ? def.sym->st_value : 0;
@@ -879,7 +897,7 @@ static void do_mips_relocs(struct dso *p, size_t *got)
size_t i, j, rel[2];
unsigned char *base = p->base;
i=0; search_vec(p->dynv, &i, DT_MIPS_LOCAL_GOTNO);
- if (p->rel_early_relative) {
+ if (p==&ldso) {
got += i;
} else {
while (i--) *got++ += (size_t)base;
@@ -1116,16 +1134,16 @@ static void update_tls_size()
* linker itself, but some of the relocations performed may need to be
* replaced later due to copy relocations in the main program. */
-void __dls2(unsigned char *base)
+void __dls2(unsigned char *base, size_t *addends)
{
Ehdr *ehdr = (void *)base;
+ if (!(saved_addends = addends)) a_crash();
ldso.base = base;
ldso.name = ldso.shortname = "libc.so";
ldso.global = 1;
ldso.phnum = ehdr->e_phnum;
ldso.phdr = (void *)(base + ehdr->e_phoff);
ldso.phentsize = ehdr->e_phentsize;
- ldso.rel_early_relative = 1;
kernel_mapped_dso(&ldso);
decode_dyn(&ldso);
@@ -1133,7 +1151,6 @@ void __dls2(unsigned char *base)
reloc_all(&ldso);
ldso.relocated = 0;
- ldso.rel_update_got = 1;
}
/* Stage 3 of the dynamic linker is called with the dynamic linker/libc