JPH06332720A - Signal control method - Google Patents

Abstract

PURPOSE:To continue a processing in a dangerous area, and to prevent a system down by setting a flag to indicate that the processing of a process is moved to the processing of the dangerous area, and blocking a signal for moving the process to an interruption processing. CONSTITUTION:At the time of executing the processing in the dangerous area, a process 12A preliminarily declares the start of the processing in the dangerous area. At the time of declaring the start of the processing in the dangerous area, the process 12A sets ON the critical flag of a process management table 13 assigned to its own process 12A. Next, the set of the signals to be blocked is designated as factors, and a 'sigsetmask' system control is issued. When the system control is issued, the signal to the process 12A is blocked, and the processing can be continued. When the processing in the dangerous area is ended, the critical flag of the process management table 13 assigned to its own process 12A is turned OFF.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal (software interrupt) control method in an online system.

[0002]

2. Description of the Related Art As an operating system for online systems, U which is an operating system for TSS developed by AT & T Bell Laboratories, USA
NIX is known.

In this UNIX, the transaction processing system on UNIX is important because it is necessary to maintain consistency between operations of a plurality of databases in one transaction.

Regarding the transaction processing system on UNIX, Nikkei Computer October 7, 1991
It is described on pages 91 to 106 of Nikkei (Nikkei BP).

By the way, in this transaction processing system, various signals (software interrupts) are provided to notify the process that some event is occurring.

[0006]

However, regarding a signal control method in the case where a signal is generated while processing is being executed in a dangerous area, for example, while a process is re-establishing a chain of management information, , Not specified.

Therefore, if a signal arrives at the process and control is passed to the interrupt process while the process is executing the process in the dangerous area, the process is terminated by the default operation of the signal and the data is processed. There is a problem that the system can be down because of the inconsistency of.

For signals and dangerous areas, U
NIX Network Programming (W. Richard.
Page 54 of Stevens, published by Toppan)
It is described on page 5.

It is an object of the present invention to provide a signal control method capable of preventing the system from going down by continuing the processing in the dangerous area even if a signal arrives.

[0010]

SUMMARY OF THE INVENTION The above object is to set a flag indicating that the process is to move to the dangerous area when the process moves to the dangerous area, and to block the signal that causes the process to move to the interrupt process. This is accomplished by resetting the flag and unblocking the signal after processing in the hazardous area is complete.

[0011]

According to the above means, the flag for blocking the signal is set in advance before the process starts the processing in the dangerous area. As a result, even if a signal occurs during execution of processing in the dangerous area, control is not passed to interrupt processing for the signal, so that processing in the dangerous area can be continued.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an online system to which the present invention is applied. An electronic computer 10 has an online control program 11 for performing transaction control according to a request from a terminal system (not shown). A plurality of business programs (processes) 12A to 12C that perform transaction processing and a process management table 13 that stores information for each process are provided.

FIG. 2 shows an example of the information stored in the process management table 13, in which only the fields necessary for the process to execute processing in the dangerous area are shown.

Process ID 21 ... Used when a process finds a process management table assigned to itself.

Critical flag 22 ... A flag indicating whether or not a process is executing a process in a dangerous area.

Signal mask 23 indicates a blocked signal, and is composed of a bit string for the number of signals to be blocked, and the bit corresponding to the blocked signal is set to "ON".

FIG. 3 is a flow chart showing the flow when the process 12A executes processing in the dangerous area, for example.
Before executing the processing in the dangerous area, the process 12A declares that the processing is started in the dangerous area (steps 31 and 32).

After that, the processing in the dangerous area is executed (step 33), and when the processing in the dangerous area is finished, it is declared that the processing in the dangerous area is finished and the processing is finished (step 34, 35).

FIG. 4 is a flow chart showing the contents of the processing for the processing start declaration in the dangerous area.
The critical flag 22 (initial value OFF) of the process management table 13 assigned to the own process 12A is set to ON (steps 41 and 42).

When the flag 22 is ON, it indicates that the process 12A is executing the process in the dangerous area.

Next, the "sigsetmask" system call is issued by specifying the set of signals to be blocked as an argument (step 43). By issuing this system call, the signal to the process 12A is blocked, and the processing can be continued.

Next, the return value of the "sigsetmask" system call is set in the signal mask 23 of the process management table 13 (step 44).

FIG. 5 is a flow chart showing the contents of the processing for the processing end declaration in the dangerous area. Since the processing in the dangerous area has already been completed, the process management table 13 assigned to the own process 12A. Turns off the critical flag 22 (steps 51, 5).
2).

Next, using the value of the signal mask 23 of the process management table 13 as an argument, "sigsetmask" is set.
Issue a "system call" to unblock the signal.

The "sigsetmask" system call is described on page 226 of the manual "HI-UX / WE2 Reference 2 (HITACH)".

[0027]

As is apparent from the above description, according to the present invention, when the processing of the process shifts to the dangerous area, a flag indicating that is set, and the process shifts to the interrupt processing by this flag. Since the signal is blocked and the flag is reset after the processing in the dangerous area is finished and the signal is unblocked, even if the signal arrives while the process is executing the processing in the dangerous area, It is possible to continue the processing in the dangerous area and prevent the system from going down.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an online system to which the present invention is applied.

FIG. 2 is an explanatory diagram showing an example of contents of a process management table.

FIG. 3 is a flowchart showing a flow when a process performs processing in a dangerous area.

FIG. 4 is a flowchart showing a process for a process start declaration in a dangerous area.

FIG. 5 is a flowchart showing a process for a process end declaration in a dangerous area.

[Explanation of symbols]

10 ... Computer, 11 ... Online control program,
12A to 12C ... Business program, 13 ... Process management table, 22 ... Critical flag.

Claims (1)

[Claims] 1. When the processing of a process shifts to a dangerous area, a flag indicating that is set, a signal for shifting the process to an interrupt processing is blocked by this flag, and after the processing in the dangerous area ends. A signal control method comprising resetting the flag and canceling the block for the signal.