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-rw-r--r--internal/syscallcompat/emulate.go193
-rw-r--r--internal/syscallcompat/sys_darwin.go184
2 files changed, 213 insertions, 164 deletions
diff --git a/internal/syscallcompat/emulate.go b/internal/syscallcompat/emulate.go
new file mode 100644
index 0000000..6cb0ea0
--- /dev/null
+++ b/internal/syscallcompat/emulate.go
@@ -0,0 +1,193 @@
+package syscallcompat
+
+import (
+ "os"
+ "path/filepath"
+ "sync"
+ "syscall"
+
+ "golang.org/x/sys/unix"
+)
+
+var chdirMutex sync.Mutex
+
+// emulateOpenat emulates the syscall for platforms that don't have it
+// in the kernel (darwin).
+func emulateOpenat(dirfd int, path string, flags int, mode uint32) (int, error) {
+ chdirMutex.Lock()
+ defer chdirMutex.Unlock()
+ if !filepath.IsAbs(path) {
+ // Save the old working directory
+ oldWd, err := os.Getwd()
+ if err != nil {
+ return -1, err
+ }
+ // Chdir to target directory
+ err = syscall.Fchdir(dirfd)
+ if err != nil {
+ return -1, err
+ }
+ // Chdir back at the end
+ defer os.Chdir(oldWd)
+ }
+ return syscall.Open(path, flags, mode)
+}
+
+// emulateRenameat emulates the syscall for platforms that don't have it
+// in the kernel (darwin).
+func emulateRenameat(olddirfd int, oldpath string, newdirfd int, newpath string) error {
+ chdirMutex.Lock()
+ defer chdirMutex.Unlock()
+ // Unless both paths are absolute we have to save the old working dir and
+ // Chdir(oldWd) back to it in the end. If we error out before the first
+ // chdir, Chdir(oldWd) is unneccassary but does no harm.
+ if !filepath.IsAbs(oldpath) || !filepath.IsAbs(newpath) {
+ oldWd, err := os.Getwd()
+ if err != nil {
+ return err
+ }
+ defer os.Chdir(oldWd)
+ }
+ // Make oldpath absolute
+ oldpath, err := dirfdAbs(olddirfd, oldpath)
+ if err != nil {
+ return err
+ }
+ // Make newpath absolute
+ newpath, err = dirfdAbs(newdirfd, newpath)
+ if err != nil {
+ return err
+ }
+ return syscall.Rename(oldpath, newpath)
+}
+
+// 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
+ }
+ defer syscall.Fchdir(cwd)
+ if (flags & unix.AT_REMOVEDIR) != 0 {
+ return syscall.Rmdir(path)
+ } else {
+ return syscall.Unlink(path)
+ }
+}
+
+// emulateMknodat emulates the syscall for platforms that don't have it
+// in the kernel (darwin).
+func emulateMknodat(dirfd int, path string, mode uint32, dev int) error {
+ chdirMutex.Lock()
+ defer chdirMutex.Unlock()
+ if !filepath.IsAbs(path) {
+ oldWd, err := os.Getwd()
+ if err != nil {
+ return err
+ }
+ defer os.Chdir(oldWd)
+ }
+ path, err := dirfdAbs(dirfd, path)
+ if err != nil {
+ return err
+ }
+ return syscall.Mknod(path, mode, dev)
+}
+
+// dirfdAbs transforms the dirfd-relative "path" to an absolute one. If the
+// path is not already absolute, this function will change the working
+// directory. The caller has to chdir back.
+func dirfdAbs(dirfd int, path string) (string, error) {
+ if filepath.IsAbs(path) {
+ return path, nil
+ }
+ err := syscall.Fchdir(dirfd)
+ if err != nil {
+ return "", err
+ }
+ wd, err := os.Getwd()
+ if err != nil {
+ return "", err
+ }
+ return filepath.Join(wd, path), nil
+}
+
+// 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
+ }
+ defer syscall.Fchdir(cwd)
+ return syscall.Chmod(path, mode)
+}
+
+// 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
+ }
+ 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
+ }
+ 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
+ }
+ defer syscall.Fchdir(cwd)
+ return syscall.Mkdir(path, mode)
+}
diff --git a/internal/syscallcompat/sys_darwin.go b/internal/syscallcompat/sys_darwin.go
index 39a225f..6238940 100644
--- a/internal/syscallcompat/sys_darwin.go
+++ b/internal/syscallcompat/sys_darwin.go
@@ -2,12 +2,7 @@ package syscallcompat
import (
"log"
- "os"
- "path/filepath"
- "sync"
"syscall"
-
- "golang.org/x/sys/unix"
)
// Sorry, fallocate is not available on OSX at all and
@@ -22,185 +17,46 @@ func Fallocate(fd int, mode uint32, off int64, len int64) error {
return syscall.EOPNOTSUPP
}
-var chdirMutex sync.Mutex
-
-// Poor man's Openat
-func Openat(dirfd int, path string, flags int, mode uint32) (int, error) {
- chdirMutex.Lock()
- defer chdirMutex.Unlock()
- if !filepath.IsAbs(path) {
- // Save the old working directory
- oldWd, err := os.Getwd()
- if err != nil {
- return -1, err
- }
- // Chdir to target directory
- err = syscall.Fchdir(dirfd)
- if err != nil {
- return -1, err
- }
- // Chdir back at the end
- defer os.Chdir(oldWd)
+// Dup3 is not available on Darwin, so we use Dup2 instead.
+func Dup3(oldfd int, newfd int, flags int) (err error) {
+ if flags != 0 {
+ log.Panic("darwin does not support dup3 flags")
}
- return syscall.Open(path, flags, mode)
+ return syscall.Dup2(oldfd, newfd)
}
-// Poor man's Renameat
-func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) error {
- chdirMutex.Lock()
- defer chdirMutex.Unlock()
- // Unless both paths are absolute we have to save the old working dir and
- // Chdir(oldWd) back to it in the end. If we error out before the first
- // chdir, Chdir(oldWd) is unneccassary but does no harm.
- if !filepath.IsAbs(oldpath) || !filepath.IsAbs(newpath) {
- oldWd, err := os.Getwd()
- if err != nil {
- return err
- }
- defer os.Chdir(oldWd)
- }
- // Make oldpath absolute
- oldpath, err := dirfdAbs(olddirfd, oldpath)
- if err != nil {
- return err
- }
- // Make newpath absolute
- newpath, err = dirfdAbs(newdirfd, newpath)
- if err != nil {
- return err
- }
- return syscall.Rename(oldpath, newpath)
-}
+////////////////////////////////////////////////////////
+//// Emulated Syscalls (see emulate.go) ////////////////
+////////////////////////////////////////////////////////
-// Poor man's Unlinkat
-func Unlinkat(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
- }
- defer syscall.Fchdir(cwd)
- if (flags & unix.AT_REMOVEDIR) != 0 {
- return syscall.Rmdir(path)
- } else {
- return syscall.Unlink(path)
- }
+func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error) {
+ return emulateOpenat(dirfd, path, flags, mode)
}
-// Poor man's Mknodat
-func Mknodat(dirfd int, path string, mode uint32, dev int) error {
- chdirMutex.Lock()
- defer chdirMutex.Unlock()
- if !filepath.IsAbs(path) {
- oldWd, err := os.Getwd()
- if err != nil {
- return err
- }
- defer os.Chdir(oldWd)
- }
- path, err := dirfdAbs(dirfd, path)
- if err != nil {
- return err
- }
- return syscall.Mknod(path, mode, dev)
+func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error) {
+ return emulateRenameat(olddirfd, oldpath, newdirfd, newpath)
}
-// dirfdAbs transforms the dirfd-relative "path" to an absolute one. If the
-// path is not already absolute, this function will change the working
-// directory. The caller has to chdir back.
-func dirfdAbs(dirfd int, path string) (string, error) {
- if filepath.IsAbs(path) {
- return path, nil
- }
- err := syscall.Fchdir(dirfd)
- if err != nil {
- return "", err
- }
- wd, err := os.Getwd()
- if err != nil {
- return "", err
- }
- return filepath.Join(wd, path), nil
+func Unlinkat(dirfd int, path string, flags int) (err error) {
+ return emulateUnlinkat(dirfd, path, flags)
}
-// Dup3 is not available on Darwin, so we use Dup2 instead.
-func Dup3(oldfd int, newfd int, flags int) (err error) {
- if flags != 0 {
- log.Panic("darwin does not support dup3 flags")
- }
- return syscall.Dup2(oldfd, newfd)
+func Mknodat(dirfd int, path string, mode uint32, dev int) (err error) {
+ return emulateMknodat(dirfd, path, mode, dev)
}
-// Poor man's Fchmodat.
func Fchmodat(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
- }
- defer syscall.Fchdir(cwd)
- return syscall.Chmod(path, mode)
+ return emulateFchmodat(dirfd, path, mode, flags)
}
-// Poor man's Fchownat.
func Fchownat(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
- }
- defer syscall.Fchdir(cwd)
- return syscall.Lchown(path, uid, gid)
+ return emulateFchownat(dirfd, path, uid, gid, flags)
}
-// Poor man's Symlinkat.
func Symlinkat(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
- }
- defer syscall.Fchdir(cwd)
- return syscall.Symlink(oldpath, newpath)
+ return emulateSymlinkat(oldpath, newdirfd, newpath)
}
-// Poor man's Mkdirat.
func Mkdirat(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
- }
- defer syscall.Fchdir(cwd)
- return syscall.Mkdir(path, mode)
+ return emulateMkdirat(dirfd, path, mode)
}