X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ldso%2Fdynlink.c;h=c6216b7c703f1b61b436d90ac77b5ae5f3c457e8;hb=f81e44a0d96c88e052e51982f9fdd6fe0a212b46;hp=9bf6924b8259716f6b312ec4fe96ba0c406fc61b;hpb=376b3c54bba7d235e5a8e2839bb333a826b19636;p=musl

diff --git a/ldso/dynlink.c b/ldso/dynlink.c
index 9bf6924b..c6216b7c 100644
--- a/ldso/dynlink.c
+++ b/ldso/dynlink.c
@@ -133,6 +133,9 @@ static struct dso *const nodeps_dummy;
 
 struct debug *_dl_debug_addr = &debug;
 
+__attribute__((__visibility__("hidden")))
+extern int __malloc_replaced;
+
 __attribute__((__visibility__("hidden")))
 void (*const __init_array_start)(void)=0, (*const __fini_array_start)(void)=0;
 
@@ -158,10 +161,26 @@ static void *laddr(const struct dso *p, size_t v)
 	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
 
@@ -476,23 +495,16 @@ static void redo_lazy_relocs()
 /* 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;
+	void __malloc_donate(char *, char *);
 	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)
@@ -500,7 +512,6 @@ 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;
@@ -1583,8 +1594,9 @@ _Noreturn void __dls3(size_t *sp)
 		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
@@ -1683,6 +1695,12 @@ _Noreturn void __dls3(size_t *sp)
 	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. */