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|
package helper
import (
"errors"
"io"
"os"
"os/exec"
"git.ophivana.moe/security/fortify/internal/proc"
)
type pipes struct {
args io.WriterTo
statP [2]*os.File
argsP [2]*os.File
ready chan error
cmd *exec.Cmd
}
func (p *pipes) pipe() error {
if p.statP[0] != nil || p.statP[1] != nil ||
p.argsP[0] != nil || p.argsP[1] != nil {
panic("attempted to pipe twice")
}
if p.args == nil {
panic("attempted to pipe without args")
}
// create pipes
if pr, pw, err := os.Pipe(); err != nil {
return err
} else {
p.argsP[0], p.argsP[1] = pr, pw
}
// create status pipes if ready signal is requested
if p.ready != nil {
if pr, pw, err := os.Pipe(); err != nil {
return err
} else {
p.statP[0], p.statP[1] = pr, pw
}
}
return nil
}
// calls pipe to create pipes and sets them up as ExtraFiles, returning their fd
func (p *pipes) prepareCmd(cmd *exec.Cmd) (argsFd, statFd int, err error) {
argsFd, statFd = -1, -1
if err = p.pipe(); err != nil {
return
}
// save a reference of cmd for future use
p.cmd = cmd
argsFd = int(proc.ExtraFile(cmd, p.argsP[0]))
if p.ready != nil {
statFd = int(proc.ExtraFile(cmd, p.statP[1]))
}
return
}
func (p *pipes) readyWriteArgs() error {
statsP, argsP := p.statP[0], p.argsP[1]
// write arguments and close args pipe
if _, err := p.args.WriteTo(argsP); err != nil {
if err1 := p.cmd.Process.Kill(); err1 != nil {
// should be unreachable
panic(err1.Error())
}
return err
} else {
if err = argsP.Close(); err != nil {
if err1 := p.cmd.Process.Kill(); err1 != nil {
// should be unreachable
panic(err1.Error())
}
return err
}
}
if p.ready != nil {
// monitor stat pipe
go func() {
n, err := statsP.Read(make([]byte, 1))
switch n {
case -1:
if err1 := p.cmd.Process.Kill(); err1 != nil {
// should be unreachable
panic(err1.Error())
}
// ensure error is not nil
if err == nil {
err = ErrStatusFault
}
p.ready <- err
case 0:
// ensure error is not nil
if err == nil {
err = ErrStatusRead
}
p.ready <- err
case 1:
p.ready <- nil
default:
panic("unreachable") // unexpected read count
}
}()
}
return nil
}
func (p *pipes) mustClosePipes() {
if err := p.argsP[0].Close(); err != nil && !errors.Is(err, os.ErrClosed) {
// unreachable
panic(err.Error())
}
if err := p.argsP[1].Close(); err != nil && !errors.Is(err, os.ErrClosed) {
// unreachable
panic(err.Error())
}
if p.ready != nil {
if err := p.statP[0].Close(); err != nil && !errors.Is(err, os.ErrClosed) {
// unreachable
panic(err.Error())
}
if err := p.statP[1].Close(); err != nil && !errors.Is(err, os.ErrClosed) {
// unreachable
panic(err.Error())
}
}
}
func (p *pipes) closeStatus() error {
if p.ready == nil {
panic("attempted to close helper with no status pipe")
}
return p.statP[0].Close()
}
|
