On Tue, Nov 29, 2022 at 9:54 AM <soe...@soeren-tempel.net> wrote:
>
> From: Sören Tempel <soe...@soeren-tempel.net>
>
> On glibc, there are two versions of strerror_r: An XSI-compliant and a
> GNU-specific version. The latter is only available on glibc. In order
> to avoid duplicating the post-processing code of error messages, this
> commit provides a separate strerror_go symbol which always refers to the
> XSI-compliant version of strerror_r (even on glibc) by selectively
> undefining the corresponding feature test macro.
>
> Previously, gofrontend assumed that the GNU-specific version of
> strerror_r was always available on Linux (which isn't the case when
> using a musl as a libc, for example). This commit thereby improves
> compatibility with Linux systems that are not using glibc.
>
> Tested on x86_64 Alpine Linux Edge and Arch Linux (glibc 2.36).
Thanks. I committed a version of this, as attached.
Ian
b6c6a3d64f2e4e9347733290aca3c75898c44b2e
diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index 7e531c3f90b..984d8324004 100644
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-5e658f4659c551330ea68f5667e4f951b218f32d
+fef6aa3c1678cdbe7dca454b2cebb369d8ba81bf
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.
diff --git a/libgo/Makefile.am b/libgo/Makefile.am
index b03e6553e90..207d5a98127 100644
--- a/libgo/Makefile.am
+++ b/libgo/Makefile.am
@@ -465,6 +465,7 @@ runtime_files = \
runtime/go-nanotime.c \
runtime/go-now.c \
runtime/go-nosys.c \
+ runtime/go-strerror.c \
runtime/go-reflect-call.c \
runtime/go-setenv.c \
runtime/go-signal.c \
diff --git a/libgo/go/syscall/errstr.go b/libgo/go/syscall/errstr.go
index 59f7a82c6d7..9f688e2a0c7 100644
--- a/libgo/go/syscall/errstr.go
+++ b/libgo/go/syscall/errstr.go
@@ -4,23 +4,19 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
-//go:build !hurd && !linux
-// +build !hurd,!linux
-
package syscall
-//sysnb strerror_r(errnum int, buf []byte) (err Errno)
-//strerror_r(errnum _C_int, buf *byte, buflen Size_t) _C_int
+import "internal/bytealg"
+
+//extern go_strerror
+func go_strerror(_C_int, *byte, Size_t) _C_int
func Errstr(errnum int) string {
- for len := 128; ; len *= 2 {
- b := make([]byte, len)
- errno := strerror_r(errnum, b)
+ for size := 128; ; size *= 2 {
+ b := make([]byte, size)
+ errno := go_strerror(_C_int(errnum), &b[0], Size_t(len(b)))
if errno == 0 {
- i := 0
- for b[i] != 0 {
- i++
- }
+ i := bytealg.IndexByte(b, 0)
// Lowercase first letter: Bad -> bad, but
// STREAM -> STREAM.
if i > 1 && 'A' <= b[0] && b[0] <= 'Z' && 'a' <= b[1]
&& b[1] <= 'z' {
@@ -29,7 +25,7 @@ func Errstr(errnum int) string {
return string(b[:i])
}
if errno != ERANGE {
- return "errstr failure"
+ return "strerror_r failure"
}
}
}
diff --git a/libgo/go/syscall/errstr_glibc.go b/libgo/go/syscall/errstr_glibc.go
deleted file mode 100644
index 03a327dbc90..00000000000
--- a/libgo/go/syscall/errstr_glibc.go
+++ /dev/null
@@ -1,34 +0,0 @@
-// errstr_glibc.go -- GNU/Linux and GNU/Hurd specific error strings.
-
-// Copyright 2010 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// We use this rather than errstr.go because on GNU/Linux sterror_r
-// returns a pointer to the error message, and may not use buf at all.
-
-//go:build hurd || linux
-// +build hurd linux
-
-package syscall
-
-import "unsafe"
-
-//sysnb strerror_r(errnum int, b []byte) (errstr *byte)
-//strerror_r(errnum _C_int, b *byte, len Size_t) *byte
-
-func Errstr(errnum int) string {
- a := make([]byte, 128)
- p := strerror_r(errnum, a)
- b := (*[1000]byte)(unsafe.Pointer(p))
- i := 0
- for b[i] != 0 {
- i++
- }
- // Lowercase first letter: Bad -> bad, but STREAM -> STREAM.
- if i > 1 && 'A' <= b[0] && b[0] <= 'Z' && 'a' <= b[1] && b[1] <= 'z' {
- c := b[0] + 'a' - 'A'
- return string(c) + string(b[1:i])
- }
- return string(b[:i])
-}
diff --git a/libgo/runtime/go-strerror.c b/libgo/runtime/go-strerror.c
new file mode 100644
index 00000000000..13d1d91df84
--- /dev/null
+++ b/libgo/runtime/go-strerror.c
@@ -0,0 +1,37 @@
+/* go-strerror.c -- wrapper around XSI-compliant strerror_r.
+
+ Copyright 2022 The Go Authors. All rights reserved.
+ Use of this source code is governed by a BSD-style
+ license that can be found in the LICENSE file. */
+
+/* There are two version of strerror_r on GNU/Linux: a GNU-specific
+ and an XSI-compliant version. The former version is only available
+ on glibc. Since glibc 2.13, the XSI-compliant version is also
+ provided by glibc if _GNU_SOURCE is not defined. Since the
+ entirety of gofrontend is compiled with _GNU_SOURCE, this file
+ exists to selectively undefine it and provides an alias to the
+ XSI-compliant version of strerror_r(3). */
+
+#ifdef __linux__
+
+/* Force selection of XSI-compliant strerror_r by glibc. */
+#undef XOPEN_SOURCE
+#define XOPEN_SOURCE 600
+#undef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200112L
+#undef _GNU_SOURCE
+
+#endif /* __linux__ */
+
+#include <string.h>
+
+#ifndef HAVE_STRERROR_R
+// Provided by go-nosys.c if not provided by libc itself.
+extern int strerror_r (int, char *, size_t);
+#endif
+
+int
+go_strerror (int errnum, char *buf, size_t buflen)
+{
+ return strerror_r (errnum, buf, buflen);
+}
