Merge pull request goplus#828 from luoliwoshang/os/errno

os:fix os.Errno 's nil pointer derefer in linux

_demo/checkfile/demo.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+func main() {
+	tempDir := os.TempDir()
+	noexist := filepath.Join(tempDir, "noexist.txt")
+
+	if _, err := os.Stat(noexist); err != nil {
+		if os.IsNotExist(err) {
+			fmt.Println("noexist:", err.Error())
+		} else {
+			fmt.Println("exist,other err:", err.Error())
+		}
+	}
+
+	if _, err := os.Open(noexist); err != nil {
+		if os.IsNotExist(err) {
+			fmt.Println("noexist:", err.Error())
+		} else {
+			fmt.Println("exist,other err:", err.Error())
+		}
+	}
+}

c/os/_os/os.c

@@ -1,4 +1,5 @@
 #include <stdlib.h>
+#include <errno.h>
 
 int llgoClearenv() {
 	extern char **environ;
@@ -7,3 +8,5 @@ int llgoClearenv() {
 	}
 	return 0;
 }
+
+int llgoErrno() { return errno; }

c/os/os.go

@@ -70,8 +70,8 @@ type (
 	StatT = syscall.Stat_t
 )
 
-//go:linkname Errno errno
-var Errno c.Int
+//go:linkname Errno C.llgoErrno
+func Errno() c.Int
 
 //go:linkname Umask C.umask
 func Umask(cmask ModeT) ModeT

c/os/os_linux.go

@@ -21,7 +21,8 @@ package os
 import "C"
 
 const (
-	LLGoPackage = "decl"
+	LLGoFiles   = "_os/os.c"
+	LLGoPackage = "link"
 )
 
 //go:linkname Clearenv C.clearenv

internal/build/_overlay/net/textproto/textproto.go

@@ -108,7 +108,7 @@ func (conn *cConn) Read(p []byte) (n int, err error) {
 	for n < len(p) {
 		result := os.Read(conn.socketFd, unsafe.Pointer(&p[n:][0]), uintptr(len(p)-n))
 		if result < 0 {
-			if os.Errno == c.Int(syscall.EINTR) {
+			if os.Errno() == c.Int(syscall.EINTR) {
 				continue
 			}
 			return n, errors.New("read error")
@@ -128,7 +128,7 @@ func (conn *cConn) Write(p []byte) (n int, err error) {
 	for n < len(p) {
 		result := os.Write(conn.socketFd, unsafe.Pointer(&p[n:][0]), uintptr(len(p)-n))
 		if result < 0 {
-			if os.Errno == c.Int(syscall.EINTR) {
+			if os.Errno() == c.Int(syscall.EINTR) {
 				continue
 			}
 			return n, errors.New("write error")
@@ -151,7 +151,7 @@ func (conn *cConn) Close() error {
 	conn.closed = true
 	result := os.Close(conn.socketFd)
 	if result < 0 {
-		return errors.New(c.GoString(c.Strerror(os.Errno)))
+		return errors.New(c.GoString(c.Strerror(os.Errno())))
 	}
 	return nil
 }

internal/lib/os/os.go

@@ -183,7 +183,7 @@ func Getwd() (dir string, err error) {
 	if wd != nil {
 		return c.GoString(wd), nil
 	}
-	return "", syscall.Errno(os.Errno)
+	return "", syscall.Errno(os.Errno())
 }
 
 // TODO(xsw):

internal/lib/os/types.go

@@ -33,7 +33,7 @@ func (f *File) write(b []byte) (int, error) {
 	if ret >= 0 {
 		return int(ret), nil
 	}
-	return 0, syscall.Errno(os.Errno)
+	return 0, syscall.Errno(os.Errno())
 }
 
 /* TODO(xsw):
@@ -56,7 +56,7 @@ func (f *File) read(b []byte) (int, error) {
 	if ret == 0 {
 		return 0, io.EOF
 	}
-	return 0, syscall.Errno(os.Errno)
+	return 0, syscall.Errno(os.Errno())
 }
 
 /* TODO(xsw):

internal/lib/syscall/exec_libc2.go

@@ -264,14 +264,14 @@ func forkAndExecInChild(argv0 *c.Char, argv, envv **c.Char, chroot, dir *c.Char,
 			// dup2(i, i) won't clear close-on-exec flag on Linux,
 			// probably not elsewhere either.
 			if ret := os.Fcntl(c.Int(fd[i]), syscall.F_SETFD, 0); ret < 0 {
-				err1 = Errno(os.Errno)
+				err1 = Errno(os.Errno())
 				goto childerror
 			}
 			continue
 		}
 		// The new fd is created NOT close-on-exec,
 		if ret := os.Dup2(c.Int(fd[i]), c.Int(i)); ret < 0 {
-			err1 = Errno(os.Errno)
+			err1 = Errno(os.Errno())
 			goto childerror
 		}
 	}

internal/lib/syscall/syscall.go

@@ -62,15 +62,15 @@ func Getcwd(buf []byte) (n int, err error) {
 	if ret != nil {
 		return int(c.Strlen(ret)), nil
 	}
-	return 0, Errno(os.Errno)
+	return 0, Errno(os.Errno())
 }
 
 func Getwd() (string, error) {
 	wd := os.Getcwd(c.Alloca(os.PATH_MAX), os.PATH_MAX)
 	if wd != nil {
 		return c.GoString(wd), nil
 	}
-	return "", Errno(os.Errno)
+	return "", Errno(os.Errno())
 }
 
 func Getpid() (pid int) {
@@ -90,47 +90,47 @@ func fork() (uintptr, Errno) {
 	if ret >= 0 {
 		return uintptr(ret), Errno(0)
 	}
-	return 0, Errno(os.Errno)
+	return 0, Errno(os.Errno())
 }
 
 func wait4(pid int, wstatus *c.Int, options int, rusage *syscall.Rusage) (wpid int, err error) {
 	ret := os.Wait4(os.PidT(pid), wstatus, c.Int(options), rusage)
 	if ret >= 0 {
 		return int(ret), nil
 	}
-	return 0, Errno(os.Errno)
+	return 0, Errno(os.Errno())
 }
 
 func Open(path string, mode int, perm uint32) (fd int, err error) {
 	ret := os.Open(c.AllocaCStr(path), c.Int(mode), os.ModeT(perm))
 	if ret >= 0 {
 		return int(ret), nil
 	}
-	return 0, Errno(os.Errno)
+	return 0, Errno(os.Errno())
 }
 
 func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
 	ret := os.Lseek(c.Int(fd), os.OffT(offset), c.Int(whence))
 	if ret >= 0 {
 		return int64(ret), nil
 	}
-	return -1, Errno(os.Errno)
+	return -1, Errno(os.Errno())
 }
 
 func Read(fd int, p []byte) (n int, err error) {
 	ret := os.Read(c.Int(fd), unsafe.Pointer(unsafe.SliceData(p)), uintptr(len(p)))
 	if ret >= 0 {
 		return ret, nil // TODO(xsw): confirm err == nil (not io.EOF) when ret == 0
 	}
-	return 0, Errno(os.Errno)
+	return 0, Errno(os.Errno())
 }
 
 func readlen(fd int, buf *byte, nbuf int) (n int, err error) {
 	ret := os.Read(c.Int(fd), unsafe.Pointer(buf), uintptr(nbuf))
 	if ret >= 0 {
 		return ret, nil // TODO(xsw): confirm err == nil (not io.EOF) when ret == 0
 	}
-	return 0, Errno(os.Errno)
+	return 0, Errno(os.Errno())
 }
 
 func Close(fd int) (err error) {
@@ -148,15 +148,15 @@ func Lstat(path string, stat *Stat_t) (err error) {
 	if ret == 0 {
 		return nil
 	}
-	return Errno(os.Errno)
+	return Errno(os.Errno())
 }
 
 func Stat(path string, stat *Stat_t) (err error) {
 	ret := os.Stat(c.AllocaCStr(path), stat)
 	if ret == 0 {
 		return nil
 	}
-	return Errno(os.Errno)
+	return Errno(os.Errno())
 }
 
 func Pipe(p []int) (err error) {

internal/lib/syscall/syscall_bsd.go

@@ -466,7 +466,7 @@ func SysctlUint32(name string) (value uint32, err error) {
 	n := uintptr(4)
 	ret := os.Sysctlbyname(c.AllocaCStr(name), unsafe.Pointer(&value), &n, nil, 0)
 	if ret != 0 {
-		err = Errno(os.Errno)
+		err = Errno(os.Errno())
 	}
 	return
 }