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1 Introduction 2 Ground Rules Building a File System 3 File Systems 4 File Content Data Structure 5 Allocation Cluster Manager 6 Exceptions and Emancipation 7 Base Classes, Testing, and More 8 File Meta Data 9 Native File Class 10 Our File System 11 Allocation Table 12 File System Support Code 13 Initializing the File System 14 Contiguous Files 15 Rebuilding the File System 16 Native File System Support Methods 17 Lookups, Wildcards, and Unicode, Oh My 18 Finishing the File System Class The Init Program 19 Hardware Abstraction and UOS Architecture 20 Init Command Mode 21 Using Our File System 22 Hardware and Device Lists 23 Fun with Stores: Partitions 24 Fun with Stores: RAID 25 Fun with Stores: RAM Disks 26 Init wrap-up The Executive 27 Overview of The Executive 28 Starting the Kernel 29 The Kernel 30 Making a Store Bootable 31 The MMC 32 The HMC 33 Loading the components 34 Using the File Processor 35 Symbols and the SSC 36 The File Processor and Device Management 37 The File Processor and File System Management 38 Finishing Executive Startup Users and Security 39 Introduction to Users and Security 40 More Fun With Stores: File Heaps 41 File Heaps, part 2 42 SysUAF 43 TUser 44 SysUAF API Terminal I/O 45 Shells and UCL 46 UOS API, the Application Side 47 UOS API, the Executive Side 48 I/O Devices 49 Streams 50 Terminal Output Filters 51 The TTerminal Class 52 Handles 53 Putting it All Together 54 Getting Terminal Input 55 QIO 56 Cooking Terminal Input 57 Putting it all together, part 2 58 Quotas and I/O UCL 59 UCL Basics 60 Symbol Substitution 61 Command execution 62 Command execution, part 2 63 Command Abbreviation 64 ASTs 65 Expressions, Part 1 66 Expressions, Part 2: Support code 67 Expressions, part 3: Parsing 68 SYS_GETJPIW and SYS_TRNLNM 69 Expressions, part 4: Evaluation UCL Lexical Functions 70 PROCESS_SCAN 71 PROCESS_SCAN, Part 2 72 TProcess updates 73 Unicode revisted 74 Lexical functions: F$CONTEXT 75 Lexical functions: F$PID 76 Lexical Functions: F$CUNITS 77 Lexical Functions: F$CVSI and F$CVUI 78 UOS Date and Time Formatting 79 Lexical Functions: F$CVTIME 80 LIB_CVTIME 81 Date/Time Contexts 82 SYS_GETTIM, LIB_Get_Timestamp, SYS_ASCTIM, and LIB_SYS_ASCTIM 83 Lexical Functions: F$DELTA_TIME 84 Lexical functions: F$DEVICE 85 SYS_DEVICE_SCAN 86 Lexical functions: F$DIRECTORY 87 Lexical functions: F$EDIT and F$ELEMENT 88 Lexical functions: F$ENVIRONMENT 89 SYS_GETUAI 90 Lexical functions: F$EXTRACT and F$IDENTIFIER 91 LIB_FAO and LIB_FAOL 92 LIB_FAO and LIB_FAOL, part 2 93 Lexical functions: F$FAO 94 File Processing Structures 95 Lexical functions: F$FILE_ATTRIBUTES 96 SYS_DISPLAY 97 Lexical functions: F$GETDVI 98 Parse_GetDVI 99 GetDVI 100 GetDVI, part 2 101 GetDVI, part 3 102 Lexical functions: F$GETJPI 103 GETJPI 104 Lexical functions: F$GETSYI 105 GETSYI 106 Lexical functions: F$INTEGER, F$LENGTH, F$LOCATE, and F$MATCH_WILD 107 Lexical function: F$PARSE 108 FILESCAN 109 SYS_PARSE 110 Lexical Functions: F$MODE, F$PRIVILEGE, and F$PROCESS 111 File Lookup Service 112 Lexical Functions: F$SEARCH 113 SYS_SEARCH 114 F$SETPRV and SYS_SETPRV 115 Lexical Functions: F$STRING, F$TIME, and F$TYPE 116 More on symbols 117 Lexical Functions: F$TRNLNM 118 SYS_TRNLNM, Part 2 119 Lexical functions: F$UNIQUE, F$USER, and F$VERIFY 120 Lexical functions: F$MESSAGE 121 TUOS_File_Wrapper 122 OPEN, CLOSE, and READ system services UCL Commands 123 WRITE 124 Symbol assignment 125 The @ command 126 @ and EXIT 127 CRELNT system service 128 DELLNT system service 129 IF...THEN...ELSE 130 Comments, labels, and GOTO 131 GOSUB and RETURN 132 CALL, SUBROUTINE, and ENDSUBROUTINE 133 ON, SET {NO}ON, and error handling 134 INQUIRE 135 SYS_WRITE Service 136 OPEN 137 CLOSE 138 DELLNM system service 139 READ 140 Command Recall 141 RECALL 142 RUN 143 LIB_RUN 144 The Data Stream Interface 145 Preparing for execution 146 EOJ and LOGOUT 147 SYS_DELPROC and LIB_GET_FOREIGN CUSPs and utilities 148 The I/O Queue 149 Timers 150 Logging in, part one 151 Logging in, part 2 152 System configuration 153 SET NODE utility 154 UUI 155 SETTERM utility 156 SETTERM utility, part 2 157 SETTERM utility, part 3 158 AUTHORIZE utility 159 AUTHORIZE utility, UI 160 AUTHORIZE utility, Access Restrictions 161 AUTHORIZE utility, Part 4 162 AUTHORIZE utility, Reporting 163 AUTHORIZE utility, Part 6 164 Authentication 165 Hashlib 166 Authenticate, Part 7 167 Logging in, part 3 168 DAY_OF_WEEK, CVT_FROM_INTERNAL_TIME, and SPAWN 169 DAY_OF_WEEK and CVT_FROM_INTERNAL_TIME 170 LIB_SPAWN 171 CREPRC 172 CREPRC, Part 2 173 COPY 174 COPY, part 2 175 COPY, part 3 176 COPY, part 4 177 LIB_Get_Default_File_Protection and LIB_Substitute_Wildcards 178 CREATESTREAM, STREAMNAME, and Set_Contiguous 179 Help Files 180 LBR Services 181 LBR Services, Part 2 182 LIBRARY utility 183 LIBRARY utility, Part 2 184 FS Services 185 FS Services, Part 2 186 Implementing Help 187 HELP 188 HELP, Part 2 189 DMG_Get_Key and LIB_Put_Formatted_Output 190 LIBRARY utility, Part 3 191 Shutting Down UOS 192 SHUTDOWN 193 WAIT 194 SETIMR 195 WAITFR and Scheduling 196 REPLY, OPCOM, and Mailboxes 197 REPLY utility 198 Mailboxes 199 BRKTHRU 200 OPCOM 201 Mailbox Services 202 Mailboxes, Part 2 203 DEFINE 204 CRELNM 205 DISABLE 206 STOP 207 OPCCRASH and SHUTDOWN 208 APPEND Glossary/Index Downloads |
CREPRC In the last article, we reviewed code that called the CREPRC system service. In this article, we will document it. CREPRC Creates a subprocess or detached process on behalf of the current process.
Format SYS_CREPRC pidadr, image, input, output, error, prvadr, quota, prcnam, baspri, uic, mbxunt, stsflg, itmlst, node, home_rad
Arguments pidadr
image
input
output
error
prvadr
quota
prcnam
baspri
uic
mbxunt
stsflg
itmlst
node
home_rad
Description This service returns creates a subprocess or detached process on behalf of the calling process. A subprocess can be created only on the current node, but a detached process can be created on the current node or another node. Subprocesses are children of the calling process, while detached processes are independent processes. Subprocesses are automatically terminated when the parent process terminates.
Condition Values Returned SS_NORMAL Normal completion of service. A couple things we need to note about this service. We are leaving the handling of remote nodes until we discuss clusters. Resource Affinity Domains (RADs) is something that we will cover in the future (if at all). Mailboxes will be discussed in the future as well. The PRC_M_NOPASSWORD and PRC_M_NOUAF flags affect the operation of the LOGIN CUSP, and we will address them in a future article. Note also that not all quotas are available to set. That is because some quotas are specific to users rather than processes. The PRC_M_TRUSTED, PRC_M_NONRANDOM, and PRC_M_CLONE_SYMBOLS flags are not found in CREPRC on VMS, but are used in LIB$SPAWN. We incorporate them here because the handling of these options ought to be done in the executive rather than Starlet. For instance, a process shouldn't even be created for a captive account, except under certain circumstances. If we don't check for that here, a program spawning a subprocess can get around the restriction by directly calling CREPRC instead of LIB_SPAWN if we were to limit the check to LIB_SPAWN. Also, the default process name should be set on process creation instead of some time thereafter. Finally, the cloning of the symbol table is done far more efficiently in the USC rather than having Starlet do it after the fact - and process creation is already a relatively expensive operation. In the next article, we will look at the code for the SYS_CREPRC service.
Copyright © 2023 by Alan Conroy. This article may be copied in whole or in part as long as this copyright is included. |