[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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| 22 | ////////// |
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| 23 | int main() |
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| 24 | { |
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| 25 | int i; |
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[434] | 26 | int ret_fork; // fork return value |
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| 27 | int ret_exec; // fork return value |
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[436] | 28 | int rcv_pid; // pid received from the wait syscall |
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[434] | 29 | int status; // used by the wait syscall |
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[427] | 30 | char string[64]; |
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| 31 | |
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| 32 | // check number of TXT channels |
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| 33 | assert( NB_TXT_CHANNELS > 1 ); |
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| 34 | |
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| 35 | // create the KSH processes (one per user terminal) |
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[434] | 36 | for( i = 1 ; i < NB_TXT_CHANNELS ; i++ ) |
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[427] | 37 | { |
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[434] | 38 | // INIT process fork process CHILD[i] |
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| 39 | ret_fork = fork(); |
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| 40 | |
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[436] | 41 | if( ret_fork < 0 ) // error in fork |
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[427] | 42 | { |
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[434] | 43 | // INIT display error message on TXT0 terminal |
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[436] | 44 | snprintf( string , 64 , "INIT cannot fork child[%d]" , i ); |
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[427] | 45 | display_string( string ); |
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| 46 | |
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[436] | 47 | // INIT suicide |
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[434] | 48 | exit( 0 ); |
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[427] | 49 | } |
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[434] | 50 | else if( ret_fork == 0 ) // we are in CHILD[i] process |
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[427] | 51 | { |
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[434] | 52 | // CHILD[i] process exec process KSH[i] |
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| 53 | ret_exec = exec( "/bin/user/ksh.elf" , NULL , NULL ); |
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| 54 | |
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| 55 | if ( ret_exec ) // error in exec |
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[427] | 56 | { |
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[436] | 57 | // CHILD[i] display error message on TXT0 terminal |
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[435] | 58 | snprintf( string , 64 , |
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[436] | 59 | "CHILD[%d] cannot exec KSH[%d] / ret_exec = %d" , i , i , ret_exec ); |
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[434] | 60 | display_string( string ); |
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[427] | 61 | } |
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| 62 | } |
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[434] | 63 | else // we are in INIT process |
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| 64 | { |
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| 65 | // INIT display CHILD[i] process PID |
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[436] | 66 | snprintf( string , 64 , "INIT created KSH[%d] / pid = %x", i , ret_fork ); |
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[434] | 67 | display_string( string ); |
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| 68 | } |
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| 69 | } |
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| 70 | |
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[435] | 71 | // This loop detects the termination of the KSH[i] processes, |
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[436] | 72 | // and recreate a new KSH[i] process when required. |
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[427] | 73 | while( 1 ) |
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| 74 | { |
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[435] | 75 | // block on child processes termination |
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[436] | 76 | rcv_pid = wait( &status ); |
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[427] | 77 | |
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[435] | 78 | if( WIFSTOPPED( status ) ) // stopped => unblock it |
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| 79 | { |
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| 80 | // display string to report unexpected KSH process block |
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[436] | 81 | snprintf( string , 64 , "KSH process %x stopped => unblock it" , rcv_pid ); |
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[435] | 82 | display_string( string ); |
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| 83 | |
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[436] | 84 | // TODO : unblock KSH |
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[435] | 85 | |
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[436] | 86 | } // end KSH stopped handling |
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| 87 | |
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[435] | 88 | if( WIFSIGNALED( status ) || WIFEXITED( status ) ) // killed => recreate it |
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| 89 | { |
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| 90 | // display string to report unexpected KSH process termination |
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[436] | 91 | snprintf( string , 64 , "KSH process %x terminated => recreate KSH", rcv_pid ); |
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[435] | 92 | display_string( string ); |
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[436] | 93 | |
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| 94 | // INIT process fork a new CHILD process |
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| 95 | ret_fork = fork(); |
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| 96 | |
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| 97 | if( ret_fork < 0 ) // error in fork |
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| 98 | { |
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| 99 | // INIT display error message on TXT0 terminal |
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| 100 | snprintf( string , 64 , "INIT cannot fork child"); |
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| 101 | display_string( string ); |
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| 102 | |
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| 103 | // INIT suicide |
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| 104 | exit( 0 ); |
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| 105 | } |
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| 106 | else if( ret_fork == 0 ) // we are in CHILD process |
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| 107 | { |
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| 108 | // CHILD process exec process KSH |
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| 109 | ret_exec = exec( "/bin/user/ksh.elf" , NULL , NULL ); |
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| 110 | |
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| 111 | if ( ret_exec ) // error in exec |
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| 112 | { |
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| 113 | // CHILD display error message on TXT0 terminal |
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| 114 | snprintf( string , 64 , "CHILD cannot exec KSH" ); |
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| 115 | display_string( string ); |
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| 116 | } |
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| 117 | } |
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| 118 | else // we are in INIT process |
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| 119 | { |
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| 120 | // INIT display new CHILD process PID |
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| 121 | snprintf( string , 64 , "INIT forked CHILD / pid = %x", ret_fork ); |
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| 122 | display_string( string ); |
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| 123 | } |
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| 124 | } // end KSH kill handling |
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[427] | 125 | } |
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| 126 | |
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| 127 | } // end main() |
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| 128 | |
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