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authorSebastian Lackner2017-11-30 21:13:46 +0100
committerrfjakob2017-12-01 09:41:52 +0100
commitf30522a0c14218ad236831d1c229968ea46ec8aa (patch)
tree97e0008ca9d302b5ee5f65800b006da5fd169fb0 /internal/syscallcompat/emulate.go
parent9bcde0c09e96e17ed7092aa5fa5f6bfc89372a8d (diff)
syscallcompat: Fix syscall emulation for absolute paths
For absolute paths, the file descriptor should be ignored. In such a case there is also no need to hold the lock or change the working directory.
Diffstat (limited to 'internal/syscallcompat/emulate.go')
-rw-r--r--internal/syscallcompat/emulate.go120
1 files changed, 65 insertions, 55 deletions
diff --git a/internal/syscallcompat/emulate.go b/internal/syscallcompat/emulate.go
index 3af45f8..0aca28e 100644
--- a/internal/syscallcompat/emulate.go
+++ b/internal/syscallcompat/emulate.go
@@ -64,18 +64,20 @@ func emulateRenameat(olddirfd int, oldpath string, newdirfd int, newpath string)
// emulateUnlinkat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateUnlinkat(dirfd int, path string, flags int) (err error) {
- chdirMutex.Lock()
- defer chdirMutex.Unlock()
- cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
- if err != nil {
- return err
- }
- defer syscall.Close(cwd)
- err = syscall.Fchdir(dirfd)
- if err != nil {
- return err
+ if !filepath.IsAbs(path) {
+ chdirMutex.Lock()
+ defer chdirMutex.Unlock()
+ cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
+ if err != nil {
+ return err
+ }
+ defer syscall.Close(cwd)
+ err = syscall.Fchdir(dirfd)
+ if err != nil {
+ return err
+ }
+ defer syscall.Fchdir(cwd)
}
- defer syscall.Fchdir(cwd)
if (flags & unix.AT_REMOVEDIR) != 0 {
return syscall.Rmdir(path)
} else {
@@ -123,18 +125,20 @@ func dirfdAbs(dirfd int, path string) (string, error) {
// emulateFchmodat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateFchmodat(dirfd int, path string, mode uint32, flags int) (err error) {
- chdirMutex.Lock()
- defer chdirMutex.Unlock()
- cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
- if err != nil {
- return err
- }
- defer syscall.Close(cwd)
- err = syscall.Fchdir(dirfd)
- if err != nil {
- return err
+ if !filepath.IsAbs(path) {
+ chdirMutex.Lock()
+ defer chdirMutex.Unlock()
+ cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
+ if err != nil {
+ return err
+ }
+ defer syscall.Close(cwd)
+ err = syscall.Fchdir(dirfd)
+ if err != nil {
+ return err
+ }
+ defer syscall.Fchdir(cwd)
}
- defer syscall.Fchdir(cwd)
// We also don't have Lchmod, so emulate it (poorly).
if flags&unix.AT_SYMLINK_NOFOLLOW != 0 {
fi, err := os.Lstat(path)
@@ -151,53 +155,59 @@ func emulateFchmodat(dirfd int, path string, mode uint32, flags int) (err error)
// emulateFchownat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateFchownat(dirfd int, path string, uid int, gid int, flags int) (err error) {
- chdirMutex.Lock()
- defer chdirMutex.Unlock()
- cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
- if err != nil {
- return err
- }
- defer syscall.Close(cwd)
- err = syscall.Fchdir(dirfd)
- if err != nil {
- return err
+ if !filepath.IsAbs(path) {
+ chdirMutex.Lock()
+ defer chdirMutex.Unlock()
+ cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
+ if err != nil {
+ return err
+ }
+ defer syscall.Close(cwd)
+ err = syscall.Fchdir(dirfd)
+ if err != nil {
+ return err
+ }
+ defer syscall.Fchdir(cwd)
}
- defer syscall.Fchdir(cwd)
return syscall.Lchown(path, uid, gid)
}
// emulateSymlinkat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateSymlinkat(oldpath string, newdirfd int, newpath string) (err error) {
- chdirMutex.Lock()
- defer chdirMutex.Unlock()
- cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
- if err != nil {
- return err
- }
- defer syscall.Close(cwd)
- err = syscall.Fchdir(newdirfd)
- if err != nil {
- return err
+ if !filepath.IsAbs(newpath) {
+ chdirMutex.Lock()
+ defer chdirMutex.Unlock()
+ cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
+ if err != nil {
+ return err
+ }
+ defer syscall.Close(cwd)
+ err = syscall.Fchdir(newdirfd)
+ if err != nil {
+ return err
+ }
+ defer syscall.Fchdir(cwd)
}
- defer syscall.Fchdir(cwd)
return syscall.Symlink(oldpath, newpath)
}
// emulateMkdirat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateMkdirat(dirfd int, path string, mode uint32) (err error) {
- chdirMutex.Lock()
- defer chdirMutex.Unlock()
- cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
- if err != nil {
- return err
- }
- defer syscall.Close(cwd)
- err = syscall.Fchdir(dirfd)
- if err != nil {
- return err
+ if !filepath.IsAbs(path) {
+ chdirMutex.Lock()
+ defer chdirMutex.Unlock()
+ cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
+ if err != nil {
+ return err
+ }
+ defer syscall.Close(cwd)
+ err = syscall.Fchdir(dirfd)
+ if err != nil {
+ return err
+ }
+ defer syscall.Fchdir(cwd)
}
- defer syscall.Fchdir(cwd)
return syscall.Mkdir(path, mode)
}