Cygwin User’s Guide Cygwin User’s Guide Copyright © 1998, 1999, 2000, 2001, 2002, 2003 Red Hat, Inc. Table of Contents 1. Cygwin Overview...................................................................................................................................1 1.1. What is it? ...................................................................................................................................1 1.2. Quick Start Guide for those more experienced with Windows...................................................1 1.3. Quick Start Guide for those more experienced with UNIX........................................................2 1.4. Are the Cygwin tools free software?...........................................................................................2 1.5. A brief history of the Cygwin project .........................................................................................3 1.6. Highlights of Cygwin Functionality ...........................................................................................3 1.6.1. Introduction ....................................................................................................................3 1.6.2. Supporting both Windows NT and 9x ............................................................................4 1.6.3. Permissions and Security................................................................................................4 1.6.4. File Access......................................................................................................................5 1.6.5. Text Mode vs. Binary Mode...........................................................................................6 1.6.6. ANSI C Library ..............................................................................................................6 1.6.7. Process Creation .............................................................................................................7 1.6.8. Signals ............................................................................................................................7 1.6.9. Sockets............................................................................................................................8 1.6.10. Select ............................................................................................................................8 2. Setting Up Cygwin ...............................................................................................................................10 2.1. Internet Setup ............................................................................................................................10 2.1.1. Download Source .........................................................................................................10 2.1.2. Selecting an Install Directory .......................................................................................11 2.1.3. Local Package Directory ..............................................................................................11 2.1.4. Connection Method ......................................................................................................11 2.1.5. Choosing Mirrors..........................................................................................................11 2.1.6. Choosing Packages.......................................................................................................12 2.1.7. Download and Installation Progress.............................................................................12 2.1.8. Icons .............................................................................................................................13 2.1.9. Post-Install Scripts........................................................................................................13 2.1.10. Troubleshooting..........................................................................................................13 2.2. Environment Variables ..............................................................................................................13 2.3. Changing Cygwin’s Maximum Memory ..................................................................................14 2.4. NT security and usage of ntsec...............................................................................................15 2.4.1. NT security ...................................................................................................................16 2.4.2. Process privileges .........................................................................................................18 2.4.3. File permissions............................................................................................................18 2.4.4. NT SIDs in Cygwin......................................................................................................20 2.4.5. The mapping leak .........................................................................................................22 2.4.6. The ACL API................................................................................................................24 2.4.7. New setuid concept.......................................................................................................24 2.4.8. Switching User Context................................................................................................27 2.4.9. Special values of user and group ids ............................................................................27 2.5. Customizing bash......................................................................................................................28 iii 3. Using Cygwin .......................................................................................................................................30 3.1. Mapping path names .................................................................................................................30 3.1.1. Introduction ..................................................................................................................30 3.1.2. The Cygwin Mount Table.............................................................................................30 3.1.3. Additional Path-related Information.............................................................................31 3.2. Text and Binary modes..............................................................................................................32 3.2.1. The Issue.......................................................................................................................32 3.2.2. The default Cygwin behavior .......................................................................................32 3.2.3. Example........................................................................................................................33 3.2.4. Binary or text? ..............................................................................................................34 3.2.5. Programming ................................................................................................................34 3.3. File permissions ........................................................................................................................35 3.4. Special filenames.......................................................................................................................35 3.4.1. DOS devices .................................................................................................................35 3.4.2. POSIX devices..............................................................................................................35 3.4.3. The .exe extension ........................................................................................................37 3.4.4. The /proc filesystem .....................................................................................................38 3.4.5. The @pathnames ..........................................................................................................38 3.5. The CYGWIN environment variable ........................................................................................39 3.6. Cygserver ..................................................................................................................................41 3.6.1. What is Cygserver?.......................................................................................................41 3.6.2. Cygserver command line options .................................................................................41 3.6.3. How to start Cygserver .................................................................................................44 3.6.4. How to use the Cygserver services...............................................................................44 3.6.5. The Cygserver configuration file ..................................................................................45 3.7. Cygwin Utilities ........................................................................................................................45 3.7.1. cygcheck .......................................................................................................................46 3.7.2. cygpath .........................................................................................................................47 3.7.3. dumper..........................................................................................................................49