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moby--moby/pkg/mount/mounter_freebsd.go
Kir Kolyshkin 6533136961 pkg/mount: wrap mount/umount errors
The errors returned from Mount and Unmount functions are raw
syscall.Errno errors (like EPERM or EINVAL), which provides
no context about what has happened and why.

Similar to os.PathError type, introduce mount.Error type
with some context. The error messages will now look like this:

> mount /tmp/mount-tests/source:/tmp/mount-tests/target, flags: 0x1001: operation not permitted

or

> mount tmpfs:/tmp/mount-test-source-516297835: operation not permitted

Before this patch, it was just

> operation not permitted

[v2: add Cause()]
[v3: rename MountError to Error, document Cause()]
[v4: fixes; audited all users]
[v5: make Error type private; changes after @cpuguy83 reviews]

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2018-12-10 20:07:02 -08:00

59 lines
1.2 KiB
Go

package mount // import "github.com/docker/docker/pkg/mount"
/*
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/_iovec.h>
#include <sys/mount.h>
#include <sys/param.h>
*/
import "C"
import (
"strings"
"syscall"
"unsafe"
)
func allocateIOVecs(options []string) []C.struct_iovec {
out := make([]C.struct_iovec, len(options))
for i, option := range options {
out[i].iov_base = unsafe.Pointer(C.CString(option))
out[i].iov_len = C.size_t(len(option) + 1)
}
return out
}
func mount(device, target, mType string, flag uintptr, data string) error {
isNullFS := false
xs := strings.Split(data, ",")
for _, x := range xs {
if x == "bind" {
isNullFS = true
}
}
options := []string{"fspath", target}
if isNullFS {
options = append(options, "fstype", "nullfs", "target", device)
} else {
options = append(options, "fstype", mType, "from", device)
}
rawOptions := allocateIOVecs(options)
for _, rawOption := range rawOptions {
defer C.free(rawOption.iov_base)
}
if errno := C.nmount(&rawOptions[0], C.uint(len(options)), C.int(flag)); errno != 0 {
return &mountError{
op: "mount",
source: device,
target: target,
flags: flag,
err: syscall.Errno(errno),
}
}
return nil
}