[427] | 1 | /////////////////////////////////////////////////////////////////////////////////////// |
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| 2 | // File : init.c |
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| 3 | // Date : January 2018 |
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| 4 | // Author : Alain Greiner |
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| 5 | /////////////////////////////////////////////////////////////////////////////////////// |
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| 6 | // This single thread application implement the "init" process for ALMOS-MKH. |
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[434] | 7 | // It uses the fork/exec syscalls to create N KSH child processes |
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| 8 | // (one child process per user terminal). |
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| 9 | // It includes the hard_config.h file to get th NB_TXT_CHANNELS parameter. |
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| 10 | // |
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| 11 | // TODO : Register the PIDs for all KSH[i] in a ksh_pid[] array. |
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| 12 | // Then calls the wait() function to block, and reactivate any child KSH process |
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| 13 | // that has been deleted, using a new fork/exec. |
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[427] | 14 | /////////////////////////////////////////////////////////////////////////////////////// |
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| 15 | |
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| 16 | #include <hard_config.h> |
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| 17 | |
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| 18 | #include <stdlib.h> |
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| 19 | #include <stdio.h> |
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| 20 | #include <pthread.h> |
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| 21 | |
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[434] | 22 | #define DELAY_BETWEEN_FORK 100000 |
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[427] | 23 | |
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| 24 | ////////// |
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| 25 | int main() |
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| 26 | { |
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| 27 | int i; |
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[434] | 28 | int ret_fork; // fork return value |
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| 29 | int ret_exec; // fork return value |
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| 30 | int received_pid; // pid received from the wait syscall |
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| 31 | int status; // used by the wait syscall |
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[427] | 32 | char string[64]; |
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| 33 | |
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| 34 | // check number of TXT channels |
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| 35 | assert( NB_TXT_CHANNELS > 1 ); |
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| 36 | |
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| 37 | // create the KSH processes (one per user terminal) |
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[434] | 38 | for( i = 1 ; i < NB_TXT_CHANNELS ; i++ ) |
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[427] | 39 | { |
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| 40 | |
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[434] | 41 | snprintf( string , 64 , "@@@ before fork / iter = %d\n" , i ); |
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| 42 | display_string( string ); |
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[427] | 43 | |
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[434] | 44 | // INIT process fork process CHILD[i] |
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| 45 | ret_fork = fork(); |
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| 46 | |
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| 47 | snprintf( string , 64 , "@@@ after fork / iter = %d / ret_fork = %d\n" , i , ret_fork ); |
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| 48 | display_string( string ); |
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| 49 | |
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| 50 | if( ret_fork< 0 ) // error in fork |
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[427] | 51 | { |
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[434] | 52 | // INIT display error message on TXT0 terminal |
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| 53 | snprintf( string , 64 , "init cannot fork child[%d]\n" , i ); |
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[427] | 54 | display_string( string ); |
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| 55 | |
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[434] | 56 | // INIT exit |
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| 57 | exit( 0 ); |
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[427] | 58 | } |
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[434] | 59 | else if( ret_fork == 0 ) // we are in CHILD[i] process |
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[427] | 60 | { |
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[434] | 61 | // CHILD[i] process exec process KSH[i] |
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| 62 | ret_exec = exec( "/bin/user/ksh.elf" , NULL , NULL ); |
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| 63 | |
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| 64 | if ( ret_exec ) // error in exec |
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[427] | 65 | { |
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| 66 | // display error message on TXT0 terminal |
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[434] | 67 | snprintf( string , 64 , "child[%d] cannot exec ksh[%d]\n" , i , i ); |
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| 68 | display_string( string ); |
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[427] | 69 | |
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[434] | 70 | // CHILD[i] exit |
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| 71 | // exit( 0 ); |
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[427] | 72 | } |
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| 73 | } |
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[434] | 74 | else // we are in INIT process |
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| 75 | { |
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| 76 | // INIT display CHILD[i] process PID |
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| 77 | snprintf( string , 64 , "INIT forked CHILD[%d] / pid = %x\n", i , ret_fork ); |
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| 78 | display_string( string ); |
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[427] | 79 | |
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[434] | 80 | // INIT delay |
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| 81 | int x; |
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| 82 | for( x=0 ; x<DELAY_BETWEEN_FORK ; x++) asm volatile ("nop"); |
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| 83 | |
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| 84 | /* |
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| 85 | // INIT wait exec completion by CHILD[i] |
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| 86 | while( 1 ) |
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| 87 | { |
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| 88 | // get terminating process PID |
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| 89 | received_pid = wait( &status ); |
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| 90 | |
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| 91 | if( received_pid == ret_fork ) break; |
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| 92 | else |
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| 93 | { |
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| 94 | snprintf( string , 64 , |
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| 95 | "expected_pid %d / received_pid %d" , ret_fork , received_pid ); |
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| 96 | display_string( string ); |
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| 97 | } |
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| 98 | } |
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| 99 | |
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| 100 | */ |
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| 101 | // INIT display string on kernel TXT0 |
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| 102 | snprintf( string , 64 , "INIT created KSH[%d]\n", i ); |
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| 103 | display_string( string ); |
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[427] | 104 | // @@@ |
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| 105 | display_process( 0 ); |
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| 106 | display_sched( 0 , 0 ); |
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| 107 | // @@@ |
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[434] | 108 | } |
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[427] | 109 | |
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[434] | 110 | } |
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| 111 | |
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[427] | 112 | // This blocking loop is only for debug, because KSH[i] processes |
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[434] | 113 | // should never be killed, and INIT should never return from the wait() function. |
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[427] | 114 | while( 1 ) |
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| 115 | { |
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| 116 | // block on child process termination |
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[434] | 117 | received_pid = wait( &status ); |
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[427] | 118 | |
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[434] | 119 | // display string to report unexpected KSH process termination |
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| 120 | snprintf( string , 64 , "KSH process %x unexpectedly terminated" , received_pid ); |
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[427] | 121 | display_string( string ); |
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| 122 | } |
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| 123 | |
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| 124 | } // end main() |
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| 125 | |
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