Exec: use ErrorConmonRead

Before, we were using -1 as a bogus value in podman to signify something went wrong when reading from a conmon pipe. However, conmon uses negative values to indicate the runtime failed, and return the runtime's exit code.

instead, we should use a bogus value that is actually bogus. Define that value in the define package as MinInt32 (-1<< 31 - 1), which is outside of the range of possible pids (-1 << 31)

Signed-off-by: Peter Hunt <pehunt@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/libpod/define/exec_codes.go b/libpod/define/exec_codes.go
index f94616b33..c2ec08666 100644
--- a/libpod/define/exec_codes.go
+++ b/libpod/define/exec_codes.go
@@ -1,6 +1,7 @@
 package define
 
 import (
+	"math"
 	"strings"
 
 	"github.com/pkg/errors"
@@ -17,6 +18,11 @@ const (
 	ExecErrorCodeCannotInvoke = 126
 	// ExecErrorCodeNotFound is the error code to return when a command cannot be found
 	ExecErrorCodeNotFound = 127
+	// ErrorConmonRead is a bogus value that can neither be a valid PID or exit code. It is
+	// used because conmon will send a negative value when sending a PID back over a pipe FD
+	// to signify something went wrong in the runtime. We need to differentiate between that
+	// value and a failure on the podman side of reading that value. Thus, we use ErrorConmonRead
+	ErrorConmonRead = math.MinInt32 - 1
 )
 
 // TranslateExecErrorToExitCode takes an error and checks whether it