Imported Upstream version 0.8.13upstream

1 files changed, 150 insertions, 0 deletions

diff --git a/lib/strptr.c b/lib/strptr.c
new file mode 100644
index 0000000..30e217e
--- /dev/null
+++ b/lib/strptr.c
@@ -0,0 +1,150 @@
+/*
+ * strptr.c - implementation of the elf_strptr(3) function.
+ * Copyright (C) 1995 - 2007 Michael Riepe
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+#include <private.h>
+
+#ifndef lint
+static const char rcsid[] = "@(#) $Id: strptr.c,v 1.12 2008/05/23 08:15:35 michael Exp $";
+#endif /* lint */
+
+char*
+elf_strptr(Elf *elf, size_t section, size_t offset) {
+    Elf_Data *data;
+    Elf_Scn *scn;
+    size_t n;
+    char *s;
+
+    if (!elf) {
+	return NULL;
+    }
+    elf_assert(elf->e_magic == ELF_MAGIC);
+    if (!(scn = elf_getscn(elf, section))) {
+	return NULL;
+    }
+    if (scn->s_index == SHN_UNDEF) {
+	seterr(ERROR_NOSTRTAB);
+	return NULL;
+    }
+    /*
+     * checking the section header is more appropriate
+     */
+    if (elf->e_class == ELFCLASS32) {
+	if (scn->s_shdr32.sh_type != SHT_STRTAB) {
+	    seterr(ERROR_NOSTRTAB);
+	    return NULL;
+	}
+    }
+#if __LIBELF64
+    else if (elf->e_class == ELFCLASS64) {
+	if (scn->s_shdr64.sh_type != SHT_STRTAB) {
+	    seterr(ERROR_NOSTRTAB);
+	    return NULL;
+	}
+    }
+#endif /* __LIBELF64 */
+    else if (valid_class(elf->e_class)) {
+	seterr(ERROR_UNIMPLEMENTED);
+	return NULL;
+    }
+    else {
+	seterr(ERROR_UNKNOWN_CLASS);
+	return NULL;
+    }
+    /*
+     * Find matching buffer
+     */
+    n = 0;
+    data = NULL;
+    if (elf->e_elf_flags & ELF_F_LAYOUT) {
+	/*
+	 * Programmer is responsible for d_off
+	 * Note: buffers may be in any order!
+	 */
+	while ((data = elf_getdata(scn, data))) {
+	    n = data->d_off;
+	    if (offset >= n && offset - n < data->d_size) {
+		/*
+		 * Found it
+		 */
+		break;
+	    }
+	}
+    }
+    else {
+	/*
+	 * Calculate offsets myself
+	 */
+	while ((data = elf_getdata(scn, data))) {
+	    if (data->d_align > 1) {
+		n += data->d_align - 1;
+		n -= n % data->d_align;
+	    }
+	    if (offset < n) {
+		/*
+		 * Invalid offset: points into a hole
+		 */
+		seterr(ERROR_BADSTROFF);
+		return NULL;
+	    }
+	    if (offset - n < data->d_size) {
+		/*
+		 * Found it
+		 */
+		break;
+	    }
+	    n += data->d_size;
+	}
+    }
+    if (data == NULL) {
+	/*
+	 * Not found
+	 */
+	seterr(ERROR_BADSTROFF);
+	return NULL;
+    }
+    if (data->d_buf == NULL) {
+	/*
+	 * Buffer is NULL (usually the programmers' fault)
+	 */
+	seterr(ERROR_NULLBUF);
+	return NULL;
+    }
+    offset -= n;
+    s = (char*)data->d_buf;
+    if (!(_elf_sanity_checks & SANITY_CHECK_STRPTR)) {
+	return s + offset;
+    }
+    /*
+     * Perform extra sanity check
+     */
+    for (n = offset; n < data->d_size; n++) {
+	if (s[n] == '\0') {
+	    /*
+	     * Return properly NUL terminated string
+	     */
+	    return s + offset;
+	}
+    }
+    /*
+     * String is not NUL terminated
+     * Return error to avoid SEGV in application
+     */
+    seterr(ERROR_UNTERM);
+    return NULL;
+}