tailieunhanh - Nuclear Power System Simulations and Operation Part 7

Tham khảo tài liệu 'nuclear power system simulations and operation part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Analysis of Error Propagation Between Software Processes 79 with return value equal to -1 which indicates an error and the external variable errno is set appropriately. Many of these are described in the manual pages and can be identified as the failure effect on the local process. However not all failure modes are represented as error cases in the manual pages. We make use of test programs to identify these. Reference Variable Failure mode Parameter shmflg Not specified at all Parameter shmflg Is not one of IPC_CREAT IPC_EXCL SHM_HUGETLB or SHM_NORESERVE Parameter shmflg Is of wrong type Parameter shmflg No permission mode is set Parameter shmflg Access permission is given to all users instead of user only Parameter shmflg Permission mode is write when it should have been read Parameter shmflg Permission mode is read when it should have been write Parameter shmflg Permission mode is set without user access Parameter shmflg IPC_EXCL specified without IPC_CREAT Parameter shmflg Wrong flag specified . IPC_CREAT IPC_EXCL when not intended Table 2. Failure modes for parameter shmflg for the shmget system call A test program is written to execute a failure mode while the failure effect is monitored. Such test programs have the possibility to execute an injected failure mode. Based on such test programs one can determine the effect of failure modes. . the effect for failure mode no permission mode is set was determined to be no processes can access the shared memory segment unless they are privileged. Checking the value of the parameter shmflg to identify whether the permission mode is set is easily done performing static analysis thus this failure mode can be detected in source code. Table 3 shows the complete FMEA for the failure modes related to the shmflg parameter of shmget from Table 2. Similarly the remaining system and library calls are analysed. The failure .