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