update

Author: adambenhassen

src/runtime/cgo.go

@@ -20,7 +20,6 @@ import "unsafe"
 //go:linkname _cgo_pthread_key_created _cgo_pthread_key_created
 //go:linkname _cgo_bindm _cgo_bindm
 //go:linkname _cgo_getstackbound _cgo_getstackbound
-//go:linkname _cgo_is_musl _cgo_is_musl
 
 var (
 	_cgo_init                     unsafe.Pointer
@@ -33,7 +32,6 @@ var (
 	_cgo_pthread_key_created      unsafe.Pointer
 	_cgo_bindm                    unsafe.Pointer
 	_cgo_getstackbound            unsafe.Pointer
-	_cgo_is_musl                  unsafe.Pointer
 )
 
 // iscgo is set to true by the runtime/cgo package

src/runtime/cgo/callbacks.go

@@ -151,10 +151,3 @@ var _cgo_yield unsafe.Pointer
 var x_cgo_getstackbound byte
 var _cgo_getstackbound = &x_cgo_getstackbound
 
-// x_cgo_is_musl is set to 1 if the C library is musl.
-
-//go:cgo_import_static x_cgo_is_musl
-//go:linkname x_cgo_is_musl x_cgo_is_musl
-//go:linkname _cgo_is_musl _cgo_is_musl
-var x_cgo_is_musl byte
-var _cgo_is_musl = &x_cgo_is_musl

src/runtime/cgo/callbacks_musl_linux.go

@@ -0,0 +1,17 @@
+// Copyright 2016 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.
+
+//go:build linux
+
+package cgo
+
+import _ "unsafe" // for go:linkname
+
+// x_cgo_is_musl is set to 1 if the C library is musl.
+
+//go:cgo_import_static x_cgo_is_musl
+//go:linkname x_cgo_is_musl x_cgo_is_musl
+//go:linkname _cgo_is_musl _cgo_is_musl
+var x_cgo_is_musl byte
+var _cgo_is_musl = &x_cgo_is_musl

src/runtime/cgo/gcc_libinit.c

@@ -17,7 +17,6 @@
 #include <stdlib.h>
 #include <string.h> // strerror
 #include <time.h>
-#include <limits.h>
 #include "libcgo.h"
 #include "libcgo_unix.h"
 

src/runtime/cgo/gcc_linux.c

@@ -64,14 +64,4 @@ threadentry(void *v)
 
 	crosscall1(ts.fn, setg_gcc, ts.g);
 	return nil;
-}
-
-// x_cgo_is_musl reports whether the C library is musl.
-int
-x_cgo_is_musl() {
-	#if defined(__GLIBC__) || defined(__UCLIBC__)
-		return 0;
-	#else
-		return 1;
-	#endif
-}
+}

src/runtime/cgo/gcc_linux_amd64.c

@@ -90,13 +90,3 @@ threadentry(void *v)
 	crosscall1(ts.fn, setg_gcc, (void*)ts.g);
 	return nil;
 }
-
-// x_cgo_is_musl reports whether the C library is musl.
-int
-x_cgo_is_musl() {
-	#if defined(__GLIBC__) || defined(__UCLIBC__)
-		return 0;
-	#else
-		return 1;
-	#endif
-}

src/runtime/cgo/gcc_linux_arm64.c

@@ -86,13 +86,3 @@ x_cgo_init(G *g, void (*setg)(void*), void **tlsg, void **tlsbase)
 		x_cgo_inittls(tlsg, tlsbase);
 	}
 }
-
-// x_cgo_is_musl reports whether the C library is musl.
-int
-x_cgo_is_musl() {
-	#if defined(__GLIBC__) || defined(__UCLIBC__)
-		return 0;
-	#else
-		return 1;
-	#endif
-}

src/runtime/cgo/gcc_musl_linux.c

@@ -0,0 +1,14 @@
+// Copyright 2009 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.
+
+//go:build linux
+
+// x_cgo_is_musl reports whether the C library is musl.
+int x_cgo_is_musl() {
+	#if defined(__GLIBC__) || defined(__UCLIBC__)
+		return 0;
+	#else
+		return 1;
+	#endif
+}

src/runtime/cgo_musl_linux.go

@@ -0,0 +1,12 @@
+// Copyright 2015 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.
+
+//go:build linux
+
+package runtime
+
+import "unsafe"
+
+//go:linkname _cgo_is_musl _cgo_is_musl
+var _cgo_is_musl unsafe.Pointer

src/runtime/os_linux.go

@@ -233,8 +233,8 @@ var auxvreadbuf [128]uintptr
 func sysargs(argc int32, argv **byte) {
 	n := argc + 1
 
-	// auxv on argv is not available on musl library/archive. avoid for musl.
-	if !((islibrary || isarchive) && GOOS == "linux" && isMusl()) {
+	// auxv on argv is not available on musl library/archive.
+	if !libmusl {
 		// skip over argv, envp to get to auxv
 		for argv_index(argv, n) != nil {
 			n++
@@ -360,6 +360,11 @@ func readRandom(r []byte) int {
 }
 
 func goenvs() {
+	if libmusl {
+		// Read envs from /proc/self/environ instead
+		envs = readNullTerminatedStringsFromFile(procEnviron)
+		return
+	}
 	goenvs_unix()
 }
 
@@ -370,6 +375,7 @@ func goenvs() {
 //go:nosplit
 //go:nowritebarrierrec
 func libpreinit() {
+	libmusl = asmcgocall(_cgo_is_musl, nil) == 1
 	initsig(true)
 }
 

src/runtime/proc.go

@@ -728,13 +728,21 @@ const (
 	_GoidCacheBatch = 16
 )
 
-// cpuinit sets up CPU feature flags and calls internal/cpu.Initialize. env should be the complete
-// value of the GODEBUG environment variable.
-func cpuinit(env string) {
+// cpuinit sets up CPU feature flags and calls internal/cpu.Initialize. 
+func cpuinit() {
 	switch GOOS {
 	case "aix", "darwin", "ios", "dragonfly", "freebsd", "netbsd", "openbsd", "illumos", "solaris", "linux":
 		cpu.DebugOptions = true
 	}
+
+	// find GODEBUG in envs
+	var env string // env should be the complete value of the GODEBUG environment variable.
+	for _, value := range envs {
+		if stringslite.HasPrefix(value, "GODEBUG=") {
+			env = value
+			break
+		}
+	}
 	cpu.Initialize(env)
 
 	// Support cpu feature variables are used in code generated by the compiler
@@ -753,49 +761,6 @@ func cpuinit(env string) {
 	}
 }
 
-// getGodebugEarly extracts the environment variable GODEBUG from the environment on
-// Unix-like operating systems and returns it. This function exists to extract GODEBUG
-// early before much of the runtime is initialized.
-func getGodebugEarly() string {
-	const prefix = "GODEBUG="
-	var env string
-	switch GOOS {
-	case "aix", "darwin", "ios", "dragonfly", "freebsd", "netbsd", "openbsd", "illumos", "solaris", "linux":
-		// Similar to goenv_unix but extracts the environment value for
-		// GODEBUG directly.
-		// TODO(moehrmann): remove when general goenvs() can be called before cpuinit()
-
-		// If the binary is an archive or a library, the operating system is Linux,
-		// and the system uses Musl, then read the environment variables from the
-		// /proc/self/environ file. Iterate over each null-terminated string read
-		// from the file. If any string has the specified prefix, return that string.
-		if (isarchive || islibrary) && GOOS == "linux" && isMusl() {
-			for _, value := range readNullTerminatedStringsFromFile(procEnviron) {
-				if stringslite.HasPrefix(value, prefix) {
-					return value
-				}
-			}
-			return env
-		}
-
-		n := int32(0)
-		for argv_index(argv, argc+1+n) != nil {
-			n++
-		}
-
-		for i := int32(0); i < n; i++ {
-			p := argv_index(argv, argc+1+i)
-			s := unsafe.String(p, findnull(p))
-
-			if stringslite.HasPrefix(s, prefix) {
-				env = gostring(p)[len(prefix):]
-				break
-			}
-		}
-	}
-	return env
-}
-
 // The bootstrap sequence is:
 //
 //	call osinit
@@ -841,10 +806,10 @@ func schedinit() {
 	moduledataverify()
 	stackinit()
 	mallocinit()
-	godebug := getGodebugEarly()
-	cpuinit(godebug) // must run before alginit
-	randinit()       // must run before alginit, mcommoninit
-	alginit()        // maps, hash, rand must not be used before this call
+	goenvs()
+	cpuinit()  // must run before alginit
+	randinit() // must run before alginit, mcommoninit
+	alginit()  // maps, hash, rand must not be used before this call
 	mcommoninit(gp.m, -1)
 	modulesinit()   // provides activeModules
 	typelinksinit() // uses maps, activeModules
@@ -855,7 +820,6 @@ func schedinit() {
 	initSigmask = gp.m.sigmask
 
 	goargs()
-	goenvs()
 	secure()
 	checkfds()
 	parsedebugvars()

src/runtime/runtime1.go

@@ -59,11 +59,6 @@ var (
 	argv **byte
 )
 
-// isMusl reports whether the Go program is linked with musl libc.
-func isMusl() bool {
-	return asmcgocall(_cgo_is_musl, nil) == 1
-}
-
 // nosplit for use in linux startup sysargs.
 //
 //go:nosplit
@@ -83,7 +78,7 @@ func goargs() {
 	}
 
 	// musl-linux library: Read argv from /proc/self/cmdline instead
-	if (isarchive || islibrary) && GOOS == "linux" && isMusl() {
+	if libmusl {
 		argslice = readNullTerminatedStringsFromFile(procCmdline)
 		return
 	}
@@ -95,12 +90,6 @@ func goargs() {
 }
 
 func goenvs_unix() {
-	// musl-linux library: Read envs from /proc/self/environ instead
-	if (isarchive || islibrary) && GOOS == "linux" && isMusl() {
-		envs = readNullTerminatedStringsFromFile(procEnviron)
-		return
-	}
-
 	// TODO(austin): ppc64 in dynamic linking mode doesn't
 	// guarantee env[] will immediately follow argv. Might cause
 	// problems.

src/runtime/runtime2.go

@@ -1248,6 +1248,9 @@ var (
 	isarchive bool // -buildmode=c-archive
 )
 
+// libmusl is set if the Go archive/library is linked against linux musl libc.
+var libmusl bool  // set by os_linux libpreinit
+
 // Must agree with internal/buildcfg.FramePointerEnabled.
 const framepointer_enabled = GOARCH == "amd64" || GOARCH == "arm64"