fortify/internal/system/tmpfiles.go
Ophestra Umiker 42e0b168e3
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fmsg: produce all output through fmsg
The behaviour of print functions from package fmt is not thread safe. Functions provided by fmsg wrap around Logger methods. This makes prefix much cleaner and makes it easy to deal with future changes to logging.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>
2024-10-21 20:47:02 +09:00

140 lines
3.3 KiB
Go

package system
import (
"errors"
"fmt"
"io"
"os"
"strconv"
"git.ophivana.moe/security/fortify/acl"
"git.ophivana.moe/security/fortify/internal/fmsg"
)
// CopyFile registers an Op that copies path dst from src.
func (sys *I) CopyFile(dst, src string) {
sys.CopyFileType(Process, dst, src)
}
// CopyFileType registers a file copying Op labelled with type et.
func (sys *I) CopyFileType(et Enablement, dst, src string) {
sys.lock.Lock()
sys.ops = append(sys.ops, &Tmpfile{et, tmpfileCopy, dst, src})
sys.lock.Unlock()
sys.UpdatePermType(et, dst, acl.Read)
}
// Link registers an Op that links dst to src.
func (sys *I) Link(oldname, newname string) {
sys.LinkFileType(Process, oldname, newname)
}
// LinkFileType registers a file linking Op labelled with type et.
func (sys *I) LinkFileType(et Enablement, oldname, newname string) {
sys.lock.Lock()
defer sys.lock.Unlock()
sys.ops = append(sys.ops, &Tmpfile{et, tmpfileLink, newname, oldname})
}
// Write registers an Op that writes dst with the contents of src.
func (sys *I) Write(dst, src string) {
sys.WriteType(Process, dst, src)
}
// WriteType registers a file writing Op labelled with type et.
func (sys *I) WriteType(et Enablement, dst, src string) {
sys.lock.Lock()
sys.ops = append(sys.ops, &Tmpfile{et, tmpfileWrite, dst, src})
sys.lock.Unlock()
sys.UpdatePermType(et, dst, acl.Read)
}
const (
tmpfileCopy uint8 = iota
tmpfileLink
tmpfileWrite
)
type Tmpfile struct {
et Enablement
method uint8
dst, src string
}
func (t *Tmpfile) Type() Enablement {
return t.et
}
func (t *Tmpfile) apply(_ *I) error {
switch t.method {
case tmpfileCopy:
fmsg.VPrintln("publishing tmpfile", t)
return fmsg.WrapErrorSuffix(copyFile(t.dst, t.src),
fmt.Sprintf("cannot copy tmpfile %q:", t.dst))
case tmpfileLink:
fmsg.VPrintln("linking tmpfile", t)
return fmsg.WrapErrorSuffix(os.Link(t.src, t.dst),
fmt.Sprintf("cannot link tmpfile %q:", t.dst))
case tmpfileWrite:
fmsg.VPrintln("writing", t)
return fmsg.WrapErrorSuffix(os.WriteFile(t.dst, []byte(t.src), 0600),
fmt.Sprintf("cannot write tmpfile %q:", t.dst))
default:
panic("invalid tmpfile method " + strconv.Itoa(int(t.method)))
}
}
func (t *Tmpfile) revert(_ *I, ec *Criteria) error {
if ec.hasType(t) {
fmsg.VPrintf("removing tmpfile %q", t.dst)
return fmsg.WrapErrorSuffix(os.Remove(t.dst),
fmt.Sprintf("cannot remove tmpfile %q:", t.dst))
} else {
fmsg.VPrintf("skipping tmpfile %q", t.dst)
return nil
}
}
func (t *Tmpfile) Is(o Op) bool {
t0, ok := o.(*Tmpfile)
return ok && t0 != nil && *t == *t0
}
func (t *Tmpfile) Path() string {
if t.method == tmpfileWrite {
return fmt.Sprintf("(%d bytes of data)", len(t.src))
}
return t.src
}
func (t *Tmpfile) String() string {
switch t.method {
case tmpfileCopy:
return fmt.Sprintf("%q from %q", t.dst, t.src)
case tmpfileLink:
return fmt.Sprintf("%q from %q", t.dst, t.src)
case tmpfileWrite:
return fmt.Sprintf("%d bytes of data to %q", len(t.src), t.dst)
default:
panic("invalid tmpfile method " + strconv.Itoa(int(t.method)))
}
}
func copyFile(dst, src string) error {
dstD, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
if err != nil {
return err
}
srcD, err := os.Open(src)
if err != nil {
return errors.Join(err, dstD.Close())
}
_, err = io.Copy(dstD, srcD)
return errors.Join(err, dstD.Close(), srcD.Close())
}