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). Alternative: Use a GNU autoconf macro to detect which version is in use. However, this requires moving the allocations and post-processing logic from Go to C. Signed-off-by: Sören Tempel <soe...@soeren-tempel.net> --- Changes since v1: Fixed a typo in the Makefile. libgo/Makefile.am | 1 + libgo/Makefile.in | 6 +++++- libgo/go/syscall/errstr.go | 9 +++------ libgo/go/syscall/errstr_glibc.go | 34 -------------------------------- libgo/runtime/go-strerror.c | 30 ++++++++++++++++++++++++++++ 5 files changed, 39 insertions(+), 41 deletions(-) delete mode 100644 libgo/go/syscall/errstr_glibc.go create mode 100644 libgo/runtime/go-strerror.c diff --git a/libgo/Makefile.am b/libgo/Makefile.am index b03e6553..207d5a98 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/Makefile.in b/libgo/Makefile.in index 16ed62a8..0407e09c 100644 --- a/libgo/Makefile.in +++ b/libgo/Makefile.in @@ -247,7 +247,7 @@ am__objects_4 = runtime/aeshash.lo runtime/go-assert.lo \ runtime/go-fieldtrack.lo runtime/go-matherr.lo \ runtime/go-memclr.lo runtime/go-memmove.lo \ runtime/go-memequal.lo runtime/go-nanotime.lo \ - runtime/go-now.lo runtime/go-nosys.lo \ + runtime/go-now.lo runtime/go-nosys.lo runtime/go-strerror.lo \ runtime/go-reflect-call.lo runtime/go-setenv.lo \ runtime/go-signal.lo runtime/go-unsafe-pointer.lo \ runtime/go-unsetenv.lo runtime/go-unwind.lo \ @@ -917,6 +917,7 @@ 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 \ @@ -1390,6 +1391,8 @@ runtime/go-now.lo: runtime/$(am__dirstamp) \ runtime/$(DEPDIR)/$(am__dirstamp) runtime/go-nosys.lo: runtime/$(am__dirstamp) \ runtime/$(DEPDIR)/$(am__dirstamp) +runtime/go-strerror.lo: runtime/$(am__dirstamp) \ + runtime/$(DEPDIR)/$(am__dirstamp) runtime/go-reflect-call.lo: runtime/$(am__dirstamp) \ runtime/$(DEPDIR)/$(am__dirstamp) runtime/go-setenv.lo: runtime/$(am__dirstamp) \ @@ -1453,6 +1456,7 @@ distclean-compile: @AMDEP_TRUE@@am__include@ @am__quote@runtime/$(DEPDIR)/go-memmove.Plo@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@runtime/$(DEPDIR)/go-nanotime.Plo@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@runtime/$(DEPDIR)/go-nosys.Plo@am__quote@ +@AMDEP_TRUE@@am__include@ @am__quote@runtime/$(DEPDIR)/go-strerror.Plo@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@runtime/$(DEPDIR)/go-now.Plo@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@runtime/$(DEPDIR)/go-reflect-call.Plo@am__quote@ @AMDEP_TRUE@@am__include@ @am__quote@runtime/$(DEPDIR)/go-setenv.Plo@am__quote@ diff --git a/libgo/go/syscall/errstr.go b/libgo/go/syscall/errstr.go index 59f7a82c..6cc73853 100644 --- a/libgo/go/syscall/errstr.go +++ b/libgo/go/syscall/errstr.go @@ -4,18 +4,15 @@ // 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 +//sysnb strerror_go(errnum int, buf []byte) (err Errno) +//strerror_go(errnum _C_int, buf *byte, buflen Size_t) _C_int func Errstr(errnum int) string { for len := 128; ; len *= 2 { b := make([]byte, len) - errno := strerror_r(errnum, b) + errno := strerror_go(errnum, b) if errno == 0 { i := 0 for b[i] != 0 { diff --git a/libgo/go/syscall/errstr_glibc.go b/libgo/go/syscall/errstr_glibc.go deleted file mode 100644 index 03a327db..00000000 --- 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 00000000..9c769cf8 --- /dev/null +++ b/libgo/runtime/go-strerror.c @@ -0,0 +1,30 @@ +/* go-strerror.c -- wrapper around XSI-compliant strerror_r(3). + + 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(3): 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). */ + +// Force selection of XSI-compliant strerror_r(3) on glibc. +#define XOPEN_SOURCE 600 +#undef _GNU_SOURCE +#include <string.h> + +#ifndef HAVE_STRERROR_R +// Provided by go-nosys.c if not provided by libc itself. +extern int strerror_r (int errnum, char *buf, size_t buflen); +#endif + +int +strerror_go (int errnum, char *buf, size_t buflen) +{ + // Always call the XSI-compliant version of strerror_r(3). + return strerror_r (errnum, buf, buflen); +}