--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.hotspot.agent/macosx/native/libsaproc/salibelf.c	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2003, 2006, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "salibelf.h"
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+extern void print_debug(const char*,...);
+
+// ELF file parsing helpers. Note that we do *not* use libelf here.
+int read_elf_header(int fd, ELF_EHDR* ehdr) {
+   if (pread(fd, ehdr, sizeof (ELF_EHDR), 0) != sizeof (ELF_EHDR) ||
+            memcmp(&ehdr->e_ident[EI_MAG0], ELFMAG, SELFMAG) != 0 ||
+            ehdr->e_version != EV_CURRENT) {
+        return 0;
+   }
+   return 1;
+}
+
+bool is_elf_file(int fd) {
+   ELF_EHDR ehdr;
+   return read_elf_header(fd, &ehdr);
+}
+
+// read program header table of an ELF file
+ELF_PHDR* read_program_header_table(int fd, ELF_EHDR* hdr) {
+   ELF_PHDR* phbuf = 0;
+   // allocate memory for program header table
+   size_t nbytes = hdr->e_phnum * hdr->e_phentsize;
+
+   if ((phbuf = (ELF_PHDR*) malloc(nbytes)) == NULL) {
+      print_debug("can't allocate memory for reading program header table\n");
+      return NULL;
+   }
+
+   if (pread(fd, phbuf, nbytes, hdr->e_phoff) != nbytes) {
+      print_debug("ELF file is truncated! can't read program header table\n");
+      free(phbuf);
+      return NULL;
+   }
+
+   return phbuf;
+}
+
+// read section header table of an ELF file
+ELF_SHDR* read_section_header_table(int fd, ELF_EHDR* hdr) {
+   ELF_SHDR* shbuf = 0;
+   // allocate memory for section header table
+   size_t nbytes = hdr->e_shnum * hdr->e_shentsize;
+
+   if ((shbuf = (ELF_SHDR*) malloc(nbytes)) == NULL) {
+      print_debug("can't allocate memory for reading section header table\n");
+      return NULL;
+   }
+
+   if (pread(fd, shbuf, nbytes, hdr->e_shoff) != nbytes) {
+      print_debug("ELF file is truncated! can't read section header table\n");
+      free(shbuf);
+      return NULL;
+   }
+
+   return shbuf;
+}
+
+// read a particular section's data
+void* read_section_data(int fd, ELF_EHDR* ehdr, ELF_SHDR* shdr) {
+  void *buf = NULL;
+  if (shdr->sh_type == SHT_NOBITS || shdr->sh_size == 0) {
+     return buf;
+  }
+  if ((buf = calloc(shdr->sh_size, 1)) == NULL) {
+     print_debug("can't allocate memory for reading section data\n");
+     return NULL;
+  }
+  if (pread(fd, buf, shdr->sh_size, shdr->sh_offset) != shdr->sh_size) {
+     free(buf);
+     print_debug("section data read failed\n");
+     return NULL;
+  }
+  return buf;
+}
+
+uintptr_t find_base_address(int fd, ELF_EHDR* ehdr) {
+  uintptr_t baseaddr = (uintptr_t)-1;
+  int cnt;
+  ELF_PHDR *phbuf, *phdr;
+
+  // read program header table
+  if ((phbuf = read_program_header_table(fd, ehdr)) == NULL) {
+    goto quit;
+  }
+
+  // the base address of a shared object is the lowest vaddr of
+  // its loadable segments (PT_LOAD)
+  for (phdr = phbuf, cnt = 0; cnt < ehdr->e_phnum; cnt++, phdr++) {
+    if (phdr->p_type == PT_LOAD && phdr->p_vaddr < baseaddr) {
+      baseaddr = phdr->p_vaddr;
+    }
+  }
+
+quit:
+  if (phbuf) free(phbuf);
+  return baseaddr;
+}