OSProcess 2.6 Author: David T. Lewis Previous released version: 2.5 Corresponding CommandShell version: 1.5 Solaris VM builders see "known bugs" below

Changes in 2.6 since 2.5: - Various changes to support CommandShell version 1.5. - Added nonBlocking mode to InternalPipe, and made InternalPipe behave more like an OSPipe. Added SUnit tests to verify pipe behavior.

OSProcess provides access to the external operating system from Squeak. A plugin is provided for Unix (and Linux) systems. OSProcess can be loaded on any platform, and placeholder classes are provided in the OSProcess hierarchy for other operating systems (Windows, Mac, OS/2, RiscOS), but support for these systems is not yet implemented.

You can: - Open a inspector on the operating system process in which Squeak is running (OSProcess thisOSProcess). - Read or write on the stdin, stdout, and stderr streams. - Access the command line, and get or set environment variables. - Fork and exec external programs, with control of the command line, environment, and stdin/stdout/stderr. - Open an inspector on a child operating system process created from Squeak, with run state and exit status of the child updated asynchronously. - Run an external command: OSProcess command: 'xeyes' - Connect directly to input and outputs of external commands: (ConnectedUnixProcess command: 'ls -l *') output - Create pipes and connect them to external processes. - Execute external command pipelines from Squeak: ((ConnectedUnixProcess command: 'ps') | 'grep squeak' | 'cut -c16-100') output - Fork an exact clone of the current running Squeak image (no image file) with parent and child Squeak processes proceeding from the same point in memory (UnixProcess forkSqueak). - Fork a Squeak using the disk based image (UnixProcess squeak). - Start a headless Squeak from the running Squeak image, giving it an expression to evaluate: (UnixProcess forkHeadlessSqueakAndDoThenQuit: [UnixProcess command: 'echo hello world']) - Tell the running image to go headless (UnixProcess decapitate), and reconnected the image with a window (UnixProcess recapitate). - Move the display to another computer on the network: (UnixProcess displayOnXServer: 'someOtherComputer') - Restart the VM on the fly (UnixProcess restartVirtualMachine). - Rebuild the VM, and restart Squeak with the new VM if the build was successful (UnixProcess makeVM). - Start your Swiki in a headless background process: (UnixProcess startSwiki: 'myswiki' onPort: 8081 loggingTo: 'log.txt')

OSProcessV2-6.cs is the main change set for OSProcess. OSProcess-sUnit-V2-6.cs contains SUnit tests (not required).

See the separate CommandShell change set for a Unix shell window which uses OSProcess.

The classes in OSProcess are:

Object OSProcess ExternalOSProcess ExternalMacOSProcess ExternalOS2Process ExternalRiscOSProcess ExternalUnixProcess ConnectedUnixProcess ExternalWindowsOSProcess ThisOSProcess MacProcess OS2Process RiscOSProcess UnixProcess WindowsProcess Stream OSPipe InternalPipe OSProcessAccessor MacOSProcessAccessor OS2OSProcessAccessor RiscOSProcessAccessor UnixOSProcessAccessor WindowsOSProcessAccessor InterpreterPlugin UnixOSProcessPlugin UnixOSProcessPluginDynamicThisSession UnixOSProcessPluginInterpreterGetThisSession UnixOSProcessPluginStaticThisSession

Known bugs in this version: - Forking a child Squeak, as in UnixProcess>>forkSqueak, results in two instances of Squeak which share a single changes file. This has no practical impact if one or the other of the Squeak processes exits without doing very much, but it would probably result in a corrupted changes file if both Squeak instances do a lot of changes. I am leaving this as is for now, since a quick fix would require one of the Squeaks to save itself under an different image name. - The connectToXDisplay method is probably dangerous from a security perspective. - UnixOSProcessAccessor>>primitiveEnsetEnv uses the function unsetenv(), which is not available on Solaris (and possibly other systems). I do not know the portable equivalent of unsetenv(), so for now Solaris users will need to comment out the call to unsetenv() and rebuild the plugin. Other than failing the SUnit tests, commenting the function out has little practical impact.