From 4f0f217c1b6a8c888ff8a1c60d1eb36cbdf14490 Mon Sep 17 00:00:00 2001
From: Nathan Binkert <binkertn@umich.edu>
Date: Sat, 26 May 2007 18:15:22 -0700
Subject: Get rid of GNU libelf and its autoconf nastiness and replace it with
 FreeBSD's implementation

--HG--
extra : convert_revision : ef9c4551b9a6b54b76a89f286ff9804c55790621
---
 ext/libelf/elf_strptr.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 ext/libelf/elf_strptr.c

(limited to 'ext/libelf/elf_strptr.c')

diff --git a/ext/libelf/elf_strptr.c b/ext/libelf/elf_strptr.c
new file mode 100644
index 000000000..b89b0eac7
--- /dev/null
+++ b/ext/libelf/elf_strptr.c
@@ -0,0 +1,131 @@
+/*-
+ * Copyright (c) 2006 Joseph Koshy
+ * 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. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 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 <assert.h>
+#include "gelf.h"
+
+#include "_libelf.h"
+
+/*
+ * Convert an ELF section#,offset pair to a string pointer.
+ */
+
+char *
+elf_strptr(Elf *e, size_t scndx, size_t offset)
+{
+        Elf_Scn *s;
+        Elf_Data *d;
+        size_t alignment, count;
+        GElf_Shdr shdr;
+
+        if (e == NULL || e->e_kind != ELF_K_ELF) {
+                LIBELF_SET_ERROR(ARGUMENT, 0);
+                return (NULL);
+        }
+
+        if ((s = elf_getscn(e, scndx)) == NULL ||
+            gelf_getshdr(s, &shdr) == NULL)
+                return (NULL);
+
+        if (shdr.sh_type != SHT_STRTAB ||
+            offset >= shdr.sh_size) {
+                LIBELF_SET_ERROR(ARGUMENT, 0);
+                return (NULL);
+        }
+
+        d = NULL;
+        if (e->e_flags & ELF_F_LAYOUT) {
+
+                /*
+                 * The application is taking responsibility for the
+                 * ELF object's layout, so we can directly translate
+                 * an offset to a `char *' address using the `d_off'
+                 * members of Elf_Data descriptors.
+                 */
+                while ((d = elf_getdata(s, d)) != NULL) {
+
+                        if (d->d_buf == 0 || d->d_size == 0)
+                                continue;
+
+                        if (d->d_type != ELF_T_BYTE) {
+                                LIBELF_SET_ERROR(DATA, 0);
+                                return (NULL);
+                        }
+
+                        if (offset >= d->d_off &&
+                            offset < d->d_off + d->d_size)
+                                return ((char *) d->d_buf + offset - d->d_off);
+                }
+        } else {
+                /*
+                 * Otherwise, the `d_off' members are not useable and
+                 * we need to compute offsets ourselves, taking into
+                 * account 'holes' in coverage of the section introduced
+                 * by alignment requirements.
+                 */
+                count = (size_t) 0;	/* cumulative count of bytes seen */
+                while ((d = elf_getdata(s, d)) != NULL && count <= offset) {
+
+                        if (d->d_buf == NULL || d->d_size == 0)
+                                continue;
+
+                        if (d->d_type != ELF_T_BYTE) {
+                                LIBELF_SET_ERROR(DATA, 0);
+                                return (NULL);
+                        }
+
+                        if ((alignment = d->d_align) > 1) {
+                                if ((alignment & (alignment - 1)) != 0) {
+                                        LIBELF_SET_ERROR(DATA, 0);
+                                        return (NULL);
+                                }
+                                count = roundup(count, alignment);
+                        }
+
+                        if (offset < count) {
+                                /* offset starts in the 'hole' */
+                                LIBELF_SET_ERROR(ARGUMENT, 0);
+                                return (NULL);
+                        }
+
+                        if (offset < count + d->d_size) {
+                                if (d->d_buf != NULL)
+                                        return ((char *) d->d_buf +
+                                            offset - count);
+                                LIBELF_SET_ERROR(DATA, 0);
+                                return (NULL);
+                        }
+
+                        count += d->d_size;
+                }
+        }
+
+        LIBELF_SET_ERROR(ARGUMENT, 0);
+        return (NULL);
+}
-- 
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