Attachment 153231 Details for Bug 115631 – Patch

[patch] Patch

atexit-dclose.diff (text/plain), 4.37 KB, created by Pedro F. Giffuni on 2015-02-20 18:45:37 UTC

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Creator: Pedro F. Giffuni

Created: 2015-02-20 18:45:37 UTC

Size: 4.37 KB

patch

obsolete

>Index: lib/libc/stdlib/atexit.h
>===================================================================
>--- lib/libc/stdlib/atexit.h	(revision 279068)
>+++ lib/libc/stdlib/atexit.h	(working copy)
>@@ -34,3 +34,23 @@
> #define	ATEXIT_SIZE	32
> 
> void __cxa_finalize(void *dso);
>+
>+#define	ATEXIT_FN_EMPTY	0
>+#define	ATEXIT_FN_STD	1
>+#define	ATEXIT_FN_CXA	2
>+
>+struct atexit {
>+	struct atexit *next;			/* next in list */
>+	int ind;				/* next index in this table */
>+	struct atexit_fn {
>+		int fn_type;			/* ATEXIT_? from above */
>+		union {
>+			void (*std_func)(void);
>+			void (*cxa_func)(void *);
>+		} fn_ptr;			/* function pointer */
>+		void *fn_arg;			/* argument for CXA callback */
>+		void *fn_dso;			/* shared module handle */
>+	} fns[ATEXIT_SIZE];			/* the table itself */
>+};
>+
>+extern struct atexit *__atexit;		/* points to head of LIFO stack */
>Index: libexec/rtld-elf/Makefile
>===================================================================
>--- libexec/rtld-elf/Makefile	(revision 279068)
>+++ libexec/rtld-elf/Makefile	(working copy)
>@@ -8,6 +8,7 @@
> MK_SSP=		no
> 
> PROG?=		ld-elf.so.1
>+CFLAGS+=	-I${.CURDIR:H:H}/lib/libc/stdlib	# atexit.h
> SRCS=		rtld_start.S \
> 		reloc.c rtld.c rtld_lock.c rtld_printf.c map_object.c \
> 		malloc.c xmalloc.c debug.c libmap.c
>Index: libexec/rtld-elf/rtld.c
>===================================================================
>--- libexec/rtld-elf/rtld.c	(revision 279068)
>+++ libexec/rtld-elf/rtld.c	(working copy)
>@@ -57,6 +57,7 @@
> #include <string.h>
> #include <unistd.h>
> 
>+#include "atexit.h"	/* Not a centrally installed header. Yet? */
> #include "debug.h"
> #include "rtld.h"
> #include "libmap.h"
>@@ -123,6 +124,7 @@
>     Obj_Entry *rtldobj, int flags, RtldLockState *lockstate);
> static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj,
>     int flags, RtldLockState *lockstate);
>+static const char *addr_to_name(const Obj_Entry *, const void *);
> static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int,
>     RtldLockState *);
> static int resolve_objects_ifunc(Obj_Entry *first, bool bind_now,
>@@ -2706,6 +2708,54 @@
>     return (p);
> }
> 
>+/*
>+ * Check if the object being dlclose-d holds a function registered
>+ * via atexit() or __cxa_atexit(). If it does, formulate a descriptive
>+ * error message and return 1. Otherwise return 0 to allow the object
>+ * to be closed/unloaded.
>+ */
>+static int
>+check_atexit(const Obj_Entry *root)
>+{
>+	static const struct atexit	*__atexit;
>+	const struct atexit	*p;
>+	int	n;
>+
>+	if (__atexit == NULL)
>+		__atexit = (struct atexit *)get_program_var_addr("__atexit");
>+
>+	for (p = __atexit; p; p = p->next) {
>+		for (n = p->ind; --n >= 0;) {
>+			void	*addr;
>+			switch (p->fns[n].fn_type) {
>+			case ATEXIT_FN_CXA:
>+				if (p->fns[n].fn_dso == root)
>+					continue;
>+				addr = p->fns[n].fn_ptr.cxa_func;
>+				break;
>+			case ATEXIT_FN_STD:
>+				addr = p->fns[n].fn_ptr.std_func;
>+				break;
>+			default:
>+				continue;
>+			}
>+			if (addr > (void *)root->mapbase &&
>+			    addr < (void *)root->mapbase + root->mapsize) {
>+				const char *name = addr_to_name(root, addr);
>+
>+				_rtld_error("shared object %s provides "
>+				    "%satexit-registered function %p (%s)",
>+				    root->path,
>+				    p->fns[n].fn_type == ATEXIT_FN_STD ?
>+					"an " : "a __cxa_",
>+				    addr, name ? name : "static?");
>+				return 1;
>+			}
>+		}
>+	}
>+	return 0;
>+}
>+
> int
> dlclose(void *handle)
> {
>@@ -2714,7 +2764,7 @@
> 
>     wlock_acquire(rtld_bind_lock, &lockstate);
>     root = dlcheck(handle);
>-    if (root == NULL) {
>+    if (root == NULL || check_atexit(root)) {
> 	lock_release(rtld_bind_lock, &lockstate);
> 	return -1;
>     }
>@@ -3986,6 +4036,34 @@
> 	return (ESRCH);
> }
> 
>+/*
>+ * If the addr-specified symbol exists in obj's symbol-table,
>+ * return its name. Otherwise, return NULL. Searches through
>+ * the entire symbol table, but we don't care, because it is
>+ * not called often.
>+ */
>+static const char *
>+addr_to_name(const Obj_Entry *obj, const void *addr)
>+{
>+	unsigned long symnum, bucket;
>+	if (obj->buckets == NULL)
>+		return NULL;
>+
>+	for (bucket = 0; bucket < obj->nbuckets; bucket++) {
>+		for (symnum = obj->buckets[bucket];
>+		    symnum != STN_UNDEF && symnum < obj->nchains;
>+		    symnum = obj->chains[symnum]) {
>+			const Elf_Sym *symp;
>+
>+			symp  = obj->symtab + symnum;
>+			if (symp->st_value + obj->relocbase == addr)
>+				return obj->strtab + symp->st_name;
>+		}
>+	}
>+
>+	return NULL;
>+}
>+
> static void
> trace_loaded_objects(Obj_Entry *obj)
> {

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Attachments on bug 115631: 153231