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Re: [PATCH] Do not depend on non-POSIX features
- From: Mark Wielaard <mjw at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Wed, 12 Oct 2016 16:22:02 +0200
- Subject: Re: [PATCH] Do not depend on non-POSIX features
Hi,
I am no fan of redefining/open coding things which reasonable can be
expected to be provided through normal GNU system headers/libs. But
these seem fairly minor. However if there are larger changes needed we
should probably pull in the relevant gnulib modules.
I added ChangeLog entries and moved the powerof2 redefinition to
system.h since that is included by all files that use it. Does the
attached patch work on your setup?
Thanks,
Mark
From 4e850b5e8618ac46bddb7c003a4168cb62f03f4f Mon Sep 17 00:00:00 2001
From: Akihiko Odaki <akihiko.odaki.4i@stu.hosei.ac.jp>
Date: Tue, 11 Oct 2016 23:10:07 +0900
Subject: [PATCH] Do not depend on some non-POSIX features.
Define/open code memrchr, rawmemchr, powerof2 and TEMP_FAILURE_RETRY if
not available through system headers.
Signed-off-by: Akihiko Odaki <akihiko.odaki.4i@stu.hosei.ac.jp>
Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
ChangeLog | 4 ++++
configure.ac | 3 +++
lib/ChangeLog | 7 +++++++
lib/fixedsizehash.h | 6 ++++++
lib/system.h | 16 ++++++++++++++++
libelf/ChangeLog | 8 ++++++++
libelf/elf_getarsym.c | 8 ++++++++
libelf/elf_strptr.c | 30 ++++++++++++++++++++++--------
8 files changed, 74 insertions(+), 8 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 07e8f57..8d61572 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2015-10-11 Akihiko Odaki <akihiko.odaki.4i@stu.hosei.ac.jp>
+
+ * configure.ac: Add memrchr, rawmemchr and powerof2 checks.
+
2016-08-04 Mark Wielaard <mjw@redhat.com>
* configure.ac: Set version to 0.167.
diff --git a/configure.ac b/configure.ac
index e5503f1..feb2ed5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -245,6 +245,9 @@ zip_LIBS="$LIBS"
LIBS="$save_LIBS"
AC_SUBST([zip_LIBS])
+AC_CHECK_DECLS([memrchr rawmemchr])
+AC_CHECK_DECLS(powerof2, , , [#include <sys/param.h>])
+
AC_CHECK_LIB([stdc++], [__cxa_demangle], [dnl
AC_DEFINE([USE_DEMANGLE], [1], [Defined if demangling is enabled])])
AM_CONDITIONAL(DEMANGLE, test "x$ac_cv_lib_stdcpp___cxa_demangle" = "xyes")
diff --git a/lib/ChangeLog b/lib/ChangeLog
index 88c71c9..afb18b1 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,5 +1,12 @@
2015-10-11 Akihiko Odaki <akihiko.odaki.4i@stu.hosei.ac.jp>
+ * fixedsizehash.h (CONCAT): Use __CONCAT when available.
+ * system.h: Include config.h and errno.h.
+ (powerof2): Define if not already defined.
+ (TEMP_FAILURE_RETRY): Define when not yet defined.
+
+2015-10-11 Akihiko Odaki <akihiko.odaki.4i@stu.hosei.ac.jp>
+
* Makefile.am (noinst_HEADERS): Add libeu.h.
* color.c: Remove system.h include, add libeu.h include.
* crc32_file.c: Likewise.
diff --git a/lib/fixedsizehash.h b/lib/fixedsizehash.h
index 18921a4..dac2a5f 100644
--- a/lib/fixedsizehash.h
+++ b/lib/fixedsizehash.h
@@ -34,7 +34,13 @@
#include <system.h>
+#ifdef __CONCAT
#define CONCAT(t1,t2) __CONCAT (t1,t2)
+#else
+#define STROF(t2) t2
+#define CONCAT_EXPANDED(t1,t2) t1 ## t2
+#define CONCAT(t1,t2) CONCAT_EXPANDED(t1,t2)
+#endif
/* Before including this file the following macros must be defined:
diff --git a/lib/system.h b/lib/system.h
index ec387c3..3a3a073 100644
--- a/lib/system.h
+++ b/lib/system.h
@@ -29,7 +29,12 @@
#ifndef LIB_SYSTEM_H
#define LIB_SYSTEM_H 1
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
#include <argp.h>
+#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/param.h>
@@ -59,6 +64,9 @@
#define MIN(m, n) ((m) < (n) ? (m) : (n))
#endif
+#ifndef HAVE_DECL_POWEROF2
+#define powerof2(x) (((x) & ((x) - 1)) == 0)
+#endif
/* A special gettext function we use if the strings are too short. */
#define sgettext(Str) \
@@ -67,6 +75,14 @@
#define gettext_noop(Str) Str
+#ifndef TEMP_FAILURE_RETRY
+#define TEMP_FAILURE_RETRY(expression) \
+ ({ ssize_t __res; \
+ do \
+ __res = expression; \
+ while (__res == -1 && errno == EINTR); \
+ __res; });
+#endif
static inline ssize_t __attribute__ ((unused))
pwrite_retry (int fd, const void *buf, size_t len, off_t off)
diff --git a/libelf/ChangeLog b/libelf/ChangeLog
index cf672bf..35af786 100644
--- a/libelf/ChangeLog
+++ b/libelf/ChangeLog
@@ -1,5 +1,13 @@
2015-10-11 Akihiko Odaki <akihiko.odaki.4i@stu.hosei.ac.jp>
+ * elf_getarsym.c (elf_getarsym): Open code rawmemchr when not
+ available.
+ * elf_strptr.c: Include stdbool.h.
+ (validate_str): New function.
+ (elf_strptr): Use validate_str instead of memrchr.
+
+2015-10-11 Akihiko Odaki <akihiko.odaki.4i@stu.hosei.ac.jp>
+
* elf32_updatefile.c: Remove sys/param.h include.
* elf32_updatenull.c: Likewise. Add system.h include.
* elf_begin.c: Remove sys/param.h.
diff --git a/libelf/elf_getarsym.c b/libelf/elf_getarsym.c
index 65c67cc..d5f0ba4 100644
--- a/libelf/elf_getarsym.c
+++ b/libelf/elf_getarsym.c
@@ -297,7 +297,15 @@ elf_getarsym (Elf *elf, size_t *ptr)
arsym[cnt].as_off = (*u32)[cnt];
arsym[cnt].as_hash = _dl_elf_hash (str_data);
+#if HAVE_DECL_RAWMEMCHR
str_data = rawmemchr (str_data, '\0') + 1;
+#else
+ char c;
+ do {
+ c = *str_data;
+ str_data++;
+ } while (c);
+#endif
}
/* At the end a special entry. */
diff --git a/libelf/elf_strptr.c b/libelf/elf_strptr.c
index ea21045..e72a3a3 100644
--- a/libelf/elf_strptr.c
+++ b/libelf/elf_strptr.c
@@ -32,6 +32,7 @@
#endif
#include <libelf.h>
+#include <stdbool.h>
#include <stddef.h>
#include "libelfP.h"
@@ -52,6 +53,22 @@ get_zdata (Elf_Scn *strscn)
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)
{
@@ -166,8 +183,7 @@ elf_strptr (Elf *elf, size_t idx, size_t offset)
{
/* Make sure the string is NUL terminated. Start from the end,
which very likely is a NUL char. */
- if (likely (memrchr (&strscn->zdata_base[offset],
- '\0', sh_size - offset) != NULL))
+ if (likely (validate_str (strscn->zdata_base, offset, sh_size)))
result = &strscn->zdata_base[offset];
else
__libelf_seterrno (ELF_E_INVALID_INDEX);
@@ -185,8 +201,7 @@ elf_strptr (Elf *elf, size_t idx, size_t offset)
/* Make sure the string is NUL terminated. Start from the end,
which very likely is a NUL char. */
- if (likely (memrchr (&strscn->rawdata_base[offset],
- '\0', sh_size - offset) != NULL))
+ if (likely (validate_str (strscn->rawdata_base, offset, sh_size)))
result = &strscn->rawdata_base[offset];
else
__libelf_seterrno (ELF_E_INVALID_INDEX);
@@ -203,10 +218,9 @@ elf_strptr (Elf *elf, size_t idx, size_t offset)
{
/* Make sure the string is NUL terminated. Start from
the end, which very likely is a NUL char. */
- if (likely (memrchr ((char *) dl->data.d.d_buf
- + (offset - dl->data.d.d_off), '\0',
- (dl->data.d.d_size
- - (offset - dl->data.d.d_off))) != NULL))
+ 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
--
1.8.3.1