exec: change exec.PathError to exec.Error
There were two issues:
1) It might not be a path error, it might be 'permission denied'.
2) The concept of $PATH is Unix-specific.
R=alex.brainman, rsc, r, mattn.jp
CC=golang-dev
https://golang.org/cl/4530096
diff --git a/src/pkg/exec/exec.go b/src/pkg/exec/exec.go
index 9582458..c6a5e06 100644
--- a/src/pkg/exec/exec.go
+++ b/src/pkg/exec/exec.go
@@ -14,14 +14,15 @@
"strconv"
)
-// PathError records the name of a binary that was not
-// found on the current $PATH.
-type PathError struct {
- Name string
+// Error records the name of a binary that failed to be be executed
+// and the reason it failed.
+type Error struct {
+ Name string
+ Error os.Error
}
-func (e *PathError) String() string {
- return "command " + strconv.Quote(e.Name) + " not found in $PATH"
+func (e *Error) String() string {
+ return "exec: " + strconv.Quote(e.Name) + ": " + e.Error.String()
}
// Cmd represents an external command being prepared or run.
@@ -32,8 +33,8 @@
// value.
Path string
- // Args is the command line arguments, including the command as Args[0].
- // If Args is empty, Run uses {Path}.
+ // Args holds command line arguments, including the command as Args[0].
+ // If the Args field is empty or nil, Run uses {Path}.
//
// In typical use, both Path and Args are set by calling Command.
Args []string
@@ -44,7 +45,7 @@
// Dir specifies the working directory of the command.
// If Dir is the empty string, Run runs the command in the
- // process's current directory.
+ // calling process's current directory.
Dir string
// Stdin specifies the process's standard input.
@@ -81,7 +82,7 @@
// resolve the path to a complete name if possible. Otherwise it uses
// name directly.
//
-// The returned Cmd's Args is constructed from the command name
+// The returned Cmd's Args field is constructed from the command name
// followed by the elements of arg, so arg should not include the
// command name itself. For example, Command("echo", "hello")
func Command(name string, arg ...string) *Cmd {
@@ -97,7 +98,7 @@
}
// interfaceEqual protects against panics from doing equality tests on
-// two interface with non-comparable underlying types
+// two interfaces with non-comparable underlying types
func interfaceEqual(a, b interface{}) bool {
defer func() {
recover()
diff --git a/src/pkg/exec/lp_test.go b/src/pkg/exec/lp_test.go
index 5408177..77d8e84 100644
--- a/src/pkg/exec/lp_test.go
+++ b/src/pkg/exec/lp_test.go
@@ -22,12 +22,12 @@
if path != "" {
t.Fatalf("LookPath path == %q when err != nil", path)
}
- perr, ok := err.(*PathError)
+ perr, ok := err.(*Error)
if !ok {
- t.Fatal("LookPath error is not a PathError")
+ t.Fatal("LookPath error is not an exec.Error")
}
if perr.Name != name {
- t.Fatalf("want PathError name %q, got %q", name, perr.Name)
+ t.Fatalf("want Error name %q, got %q", name, perr.Name)
}
}
}
diff --git a/src/pkg/exec/lp_unix.go b/src/pkg/exec/lp_unix.go
index 44f8434..3fc3be8 100644
--- a/src/pkg/exec/lp_unix.go
+++ b/src/pkg/exec/lp_unix.go
@@ -9,12 +9,18 @@
"strings"
)
-func canExec(file string) bool {
+// ErrNotFound is the error resulting if a path search failed to find an executable file.
+var ErrNotFound = os.ErrorString("executable file not found in $PATH")
+
+func findExecutable(file string) os.Error {
d, err := os.Stat(file)
if err != nil {
- return false
+ return err
}
- return d.IsRegular() && d.Permission()&0111 != 0
+ if d.IsRegular() && d.Permission()&0111 != 0 {
+ return nil
+ }
+ return os.EPERM
}
// LookPath searches for an executable binary named file
@@ -26,10 +32,11 @@
// but that would not match all the Unix shells.
if strings.Contains(file, "/") {
- if canExec(file) {
+ err := findExecutable(file)
+ if err == nil {
return file, nil
}
- return "", &PathError{file}
+ return "", &Error{file, err}
}
pathenv := os.Getenv("PATH")
for _, dir := range strings.Split(pathenv, ":", -1) {
@@ -37,9 +44,9 @@
// Unix shell semantics: path element "" means "."
dir = "."
}
- if canExec(dir + "/" + file) {
+ if err := findExecutable(dir + "/" + file); err == nil {
return dir + "/" + file, nil
}
}
- return "", &PathError{file}
+ return "", &Error{file, ErrNotFound}
}
diff --git a/src/pkg/exec/lp_windows.go b/src/pkg/exec/lp_windows.go
index d357575..7588610 100644
--- a/src/pkg/exec/lp_windows.go
+++ b/src/pkg/exec/lp_windows.go
@@ -9,15 +9,21 @@
"strings"
)
-func chkStat(file string) bool {
+// ErrNotFound is the error resulting if a path search failed to find an executable file.
+var ErrNotFound = os.ErrorString("executable file not found in %PATH%")
+
+func chkStat(file string) os.Error {
d, err := os.Stat(file)
if err != nil {
- return false
+ return err
}
- return d.IsRegular()
+ if d.IsRegular() {
+ return nil
+ }
+ return os.EPERM
}
-func canExec(file string, exts []string) (string, bool) {
+func findExecutable(file string, exts []string) (string, os.Error) {
if len(exts) == 0 {
return file, chkStat(file)
}
@@ -28,14 +34,14 @@
}
}
for _, e := range exts {
- if f := file + e; chkStat(f) {
- return f, true
+ if f := file + e; chkStat(f) == nil {
+ return f, nil
}
}
- return ``, false
+ return ``, ErrNotFound
}
-func LookPath(file string) (string, os.Error) {
+func LookPath(file string) (f string, err os.Error) {
exts := []string{}
if x := os.Getenv(`PATHEXT`); x != `` {
exts = strings.Split(strings.ToLower(x), `;`, -1)
@@ -46,21 +52,21 @@
}
}
if strings.Contains(file, `\`) || strings.Contains(file, `/`) {
- if f, ok := canExec(file, exts); ok {
- return f, nil
+ if f, err = findExecutable(file, exts); err == nil {
+ return
}
- return ``, &PathError{file}
+ return ``, &Error{file, err}
}
if pathenv := os.Getenv(`PATH`); pathenv == `` {
- if f, ok := canExec(`.\`+file, exts); ok {
- return f, nil
+ if f, err = findExecutable(`.\`+file, exts); err == nil {
+ return
}
} else {
for _, dir := range strings.Split(pathenv, `;`, -1) {
- if f, ok := canExec(dir+`\`+file, exts); ok {
- return f, nil
+ if f, err = findExecutable(dir+`\`+file, exts); err == nil {
+ return
}
}
}
- return ``, &PathError{file}
+ return ``, &Error{file, ErrNotFound}
}
