1 files changed, 106 insertions, 0 deletions
diff --git a/lib/libc/gen/elf_utils.c b/lib/libc/gen/elf_utils.c
new file mode 100644
index 000000000000..3714a0dc42b5
--- /dev/null
+++ b/lib/libc/gen/elf_utils.c
@@ -0,0 +1,106 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2010 Konstantin Belousov <kib@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/auxv.h>
+#include <sys/mman.h>
+#include <sys/resource.h>
+#include <sys/sysctl.h>
+
+#include <machine/tls.h>
+
+#include <link.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "libc_private.h"
+
+void __pthread_map_stacks_exec(void);
+
+int
+__elf_phdr_match_addr(struct dl_phdr_info *phdr_info, void *addr)
+{
+	const Elf_Phdr *ph;
+	int i;
+
+	for (i = 0; i < phdr_info->dlpi_phnum; i++) {
+		ph = &phdr_info->dlpi_phdr[i];
+		if (ph->p_type != PT_LOAD)
+			continue;
+
+		/* ELFv1 ABI for powerpc64 passes function descriptor
+		 * pointers around, not function pointers.  The function
+		 * descriptors live in .opd, which is a non-executable segment.
+		 * The PF_X check would therefore make all address checks fail,
+		 * causing a crash in some instances.  Don't skip over
+		 * non-executable segments in the ELFv1 powerpc64 case.
+		 */
+#if !defined(__powerpc64__) || (defined(_CALL_ELF) && _CALL_ELF == 2)
+		if ((ph->p_flags & PF_X) == 0)
+			continue;
+#endif
+
+		if (phdr_info->dlpi_addr + ph->p_vaddr <= (uintptr_t)addr &&
+		    (uintptr_t)addr < phdr_info->dlpi_addr +
+		    ph->p_vaddr + ph->p_memsz)
+			break;
+	}
+	return (i != phdr_info->dlpi_phnum);
+}
+
+void
+__libc_map_stacks_exec(void)
+{
+	int mib[2];
+	struct rlimit rlim;
+	u_long usrstack, stacksz;
+	size_t len;
+	
+	if (_elf_aux_info(AT_USRSTACKBASE, &usrstack, sizeof(usrstack)) != 0) {
+		mib[0] = CTL_KERN;
+		mib[1] = KERN_USRSTACK;
+		len = sizeof(usrstack);
+		if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) == -1)
+			return;
+	}
+	if (_elf_aux_info(AT_USRSTACKLIM, &stacksz, sizeof(stacksz)) != 0) {
+		if (getrlimit(RLIMIT_STACK, &rlim) == -1)
+			return;
+		stacksz = rlim.rlim_cur;
+	}
+	mprotect((void *)(uintptr_t)(usrstack - stacksz), stacksz,
+	    _rtld_get_stack_prot());
+}
+
+#pragma weak __pthread_map_stacks_exec
+void
+__pthread_map_stacks_exec(void)
+{
+
+	((void (*)(void))__libc_interposing[INTERPOS_map_stacks_exec])();
+}