fix: return tty size in container_inspect_linux.go

In the output of podman inspect, there is a field for the container's TTY size (ConsoleSize), which Podman presently only returns [0,0].
This PR updates the console size field for containers with terminal enabled.
For cases where there is an issue with getting the size, suitable debug information is given, no update happens and default [0,0] is returned.
This implementation is only for Linux systems.
For FreeBSD, the console size is not implemented yet so, adds a todo for that.

Fixes: #28368

Signed-off-by: Priyansh Sao <saopriyansh06@gmail.com>

Author: priyanshsao

libpod/container_inspect.go

@@ -630,12 +630,6 @@ func (c *Container) generateInspectContainerHostConfig(ctrSpec *spec.Spec, named
 		}
 	}
 
-	// Terminal size
-	// We can't actually get this for now...
-	// So default to something sane.
-	// TODO: Populate this.
-	hostConfig.ConsoleSize = []uint{0, 0}
-
 	return hostConfig, nil
 }
 

libpod/container_inspect_freebsd.go

@@ -24,5 +24,11 @@ func (c *Container) platformInspectContainerHostConfig(ctrSpec *spec.Spec, hostC
 		return err
 	}
 
+	// Console size
+	// We can't actually get this for now...
+	// So default to something sane.
+	// TODO: Populate this.
+	hostConfig.ConsoleSize = []uint{0, 0}
+
 	return nil
 }

libpod/container_inspect_linux.go

@@ -4,6 +4,7 @@ package libpod
 
 import (
 	"fmt"
+	"os"
 	"sort"
 	"strings"
 
@@ -14,6 +15,7 @@ import (
 	"go.podman.io/podman/v6/libpod/define"
 	"go.podman.io/podman/v6/pkg/util"
 	"go.podman.io/storage/types"
+	"golang.org/x/term"
 )
 
 func (c *Container) platformInspectContainerHostConfig(ctrSpec *spec.Spec, hostConfig *define.InspectContainerHostConfig) error {
@@ -306,6 +308,29 @@ func (c *Container) platformInspectContainerHostConfig(ctrSpec *spec.Spec, hostC
 		return err
 	}
 
+	// ConsoleSize.
+	// Default to [0,0] if we can't get it for some reason,
+	// or if the container doesn't have a TTY.
+	hostConfig.ConsoleSize = []uint{0, 0}
+
+	if c.Terminal() {
+		procPath := fmt.Sprintf("/proc/%d/fd/0", c.state.PID)
+
+		f, err := os.Open(procPath)
+		if err != nil {
+			logrus.Debugf("unable to get console size for container %s: %v", c.ID(), err)
+		} else {
+			defer f.Close()
+
+			width, height, err := term.GetSize(int(f.Fd()))
+			if err != nil {
+				logrus.Debugf("could not get terminal size: %v", err)
+			} else {
+				hostConfig.ConsoleSize = []uint{uint(width), uint(height)}
+			}
+		}
+	}
+
 	return nil
 }