Squashed 'third_party/elfutils/' content from commit 555e15e
Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/libelf/elf_strptr.c b/libelf/elf_strptr.c
new file mode 100644
index 0000000..e72a3a3
--- /dev/null
+++ b/libelf/elf_strptr.c
@@ -0,0 +1,240 @@
+/* Return string pointer from string section.
+ Copyright (C) 1998-2002, 2004, 2008, 2009, 2015 Red Hat, Inc.
+ This file is part of elfutils.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 1998.
+
+ This file is free software; you can redistribute it and/or modify
+ it under the terms of either
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at
+ your option) any later version
+
+ or
+
+ * the GNU General Public License as published by the Free
+ Software Foundation; either version 2 of the License, or (at
+ your option) any later version
+
+ or both in parallel, as here.
+
+ elfutils 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 for more details.
+
+ You should have received copies of the GNU General Public License and
+ the GNU Lesser General Public License along with this program. If
+ not, see <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <libelf.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+#include "libelfP.h"
+
+
+static void *
+get_zdata (Elf_Scn *strscn)
+{
+ size_t zsize, zalign;
+ void *zdata = __libelf_decompress_elf (strscn, &zsize, &zalign);
+ if (zdata == NULL)
+ return NULL;
+
+ strscn->zdata_base = zdata;
+ strscn->zdata_size = zsize;
+ strscn->zdata_align = zalign;
+
+ return zdata;
+}
+
+static bool validate_str (const char *str, size_t from, size_t to)
+{
+#if HAVE_DECL_MEMRCHR
+ return memrchr (&str[from], '\0', to - from) != NULL;
+#else
+ do {
+ if (to <= from)
+ return false;
+
+ to--;
+ } while (str[to]);
+
+ return true;
+#endif
+}
+
+char *
+elf_strptr (Elf *elf, size_t idx, size_t offset)
+{
+ if (elf == NULL)
+ return NULL;
+
+ if (elf->kind != ELF_K_ELF)
+ {
+ __libelf_seterrno (ELF_E_INVALID_HANDLE);
+ return NULL;
+ }
+
+ rwlock_rdlock (elf->lock);
+
+ char *result = NULL;
+ Elf_Scn *strscn;
+
+ /* Find the section in the list. */
+ Elf_ScnList *runp = (elf->class == ELFCLASS32
+ || (offsetof (struct Elf, state.elf32.scns)
+ == offsetof (struct Elf, state.elf64.scns))
+ ? &elf->state.elf32.scns : &elf->state.elf64.scns);
+ while (1)
+ {
+ if (idx < runp->max)
+ {
+ if (idx < runp->cnt)
+ strscn = &runp->data[idx];
+ else
+ {
+ __libelf_seterrno (ELF_E_INVALID_INDEX);
+ goto out;
+ }
+ break;
+ }
+
+ idx -= runp->max;
+
+ runp = runp->next;
+ if (runp == NULL)
+ {
+ __libelf_seterrno (ELF_E_INVALID_INDEX);
+ goto out;
+ }
+ }
+
+ size_t sh_size = 0;
+ if (elf->class == ELFCLASS32)
+ {
+ Elf32_Shdr *shdr = strscn->shdr.e32 ?: __elf32_getshdr_rdlock (strscn);
+ if (unlikely (shdr->sh_type != SHT_STRTAB))
+ {
+ /* This is no string section. */
+ __libelf_seterrno (ELF_E_INVALID_SECTION);
+ goto out;
+ }
+
+ if ((shdr->sh_flags & SHF_COMPRESSED) == 0)
+ sh_size = shdr->sh_size;
+ else
+ {
+ if (strscn->zdata_base == NULL && get_zdata (strscn) == NULL)
+ goto out;
+ sh_size = strscn->zdata_size;
+ }
+
+ if (unlikely (offset >= sh_size))
+ {
+ /* The given offset is too big, it is beyond this section. */
+ __libelf_seterrno (ELF_E_OFFSET_RANGE);
+ goto out;
+ }
+ }
+ else
+ {
+ Elf64_Shdr *shdr = strscn->shdr.e64 ?: __elf64_getshdr_rdlock (strscn);
+ if (unlikely (shdr->sh_type != SHT_STRTAB))
+ {
+ /* This is no string section. */
+ __libelf_seterrno (ELF_E_INVALID_SECTION);
+ goto out;
+ }
+
+ if ((shdr->sh_flags & SHF_COMPRESSED) == 0)
+ sh_size = shdr->sh_size;
+ else
+ {
+ if (strscn->zdata_base == NULL && get_zdata (strscn) == NULL)
+ goto out;
+ sh_size = strscn->zdata_size;
+ }
+
+ if (unlikely (offset >= sh_size))
+ {
+ /* The given offset is too big, it is beyond this section. */
+ __libelf_seterrno (ELF_E_OFFSET_RANGE);
+ goto out;
+ }
+ }
+
+ if (strscn->rawdata_base == NULL && ! strscn->data_read)
+ {
+ rwlock_unlock (elf->lock);
+ rwlock_wrlock (elf->lock);
+ if (strscn->rawdata_base == NULL && ! strscn->data_read
+ /* Read the section data. */
+ && __libelf_set_rawdata_wrlock (strscn) != 0)
+ goto out;
+ }
+
+ if (unlikely (strscn->zdata_base != NULL))
+ {
+ /* Make sure the string is NUL terminated. Start from the end,
+ which very likely is a NUL char. */
+ if (likely (validate_str (strscn->zdata_base, offset, sh_size)))
+ result = &strscn->zdata_base[offset];
+ else
+ __libelf_seterrno (ELF_E_INVALID_INDEX);
+ }
+ else if (likely (strscn->data_list_rear == NULL))
+ {
+ // XXX The above is currently correct since elf_newdata will
+ // make sure to convert the rawdata into the datalist if
+ // necessary. But it would be more efficient to keep the rawdata
+ // unconverted and only then iterate over the rest of the (newly
+ // added data) list. Note that when the ELF file is mmapped
+ // rawdata_base can be set while rawdata.d hasn't been
+ // initialized yet (when data_read is zero). So we cannot just
+ // look at the rawdata.d.d_size.
+
+ /* Make sure the string is NUL terminated. Start from the end,
+ which very likely is a NUL char. */
+ if (likely (validate_str (strscn->rawdata_base, offset, sh_size)))
+ result = &strscn->rawdata_base[offset];
+ else
+ __libelf_seterrno (ELF_E_INVALID_INDEX);
+ }
+ else
+ {
+ /* This is a file which is currently created. Use the list of
+ data blocks. */
+ struct Elf_Data_List *dl = &strscn->data_list;
+ while (dl != NULL)
+ {
+ if (offset >= (size_t) dl->data.d.d_off
+ && offset < dl->data.d.d_off + dl->data.d.d_size)
+ {
+ /* Make sure the string is NUL terminated. Start from
+ the end, which very likely is a NUL char. */
+ if (likely (validate_str ((char *) dl->data.d.d_buf,
+ offset - dl->data.d.d_off,
+ dl->data.d.d_size)))
+ result = ((char *) dl->data.d.d_buf
+ + (offset - dl->data.d.d_off));
+ else
+ __libelf_seterrno (ELF_E_INVALID_INDEX);
+ break;
+ }
+
+ dl = dl->next;
+ }
+ }
+
+ out:
+ rwlock_unlock (elf->lock);
+
+ return result;
+}
+INTDEF(elf_strptr)