Changeset 434 for trunk/user/init


Ignore:
Timestamp:
Feb 14, 2018, 3:41:31 PM (4 years ago)
Author:
alain
Message:

blap

File:
1 edited

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Added
Removed
  • trunk/user/init/init.c

    r427 r434  
    55///////////////////////////////////////////////////////////////////////////////////////
    66// This single thread application implement the "init" process for ALMOS-MKH.
    7 // - It uses the fork/exec syscalls to create N KSH child processes
    8 //   (one child process per user terminal), and register the corresponding PIDs
    9 //   in the ksh_pid[] array. Then it calls the wait() function to block.
    10 // - It is reactivated when any child KSH process is terminated by a SIGKILL signal,
    11 //   or stopped by a SIGSTOP signal. In case of SIGKILL, it scan all registered KSH
    12 //   processes and re-creates each killed KSH process, using a new fork/exec.
    13 // It includes the hard_config.h file to get the NB_TXT_CHANNELS parameter.
     7// It uses the fork/exec syscalls to create N KSH child processes
     8// (one child process per user terminal).
     9// It includes the hard_config.h file to get th NB_TXT_CHANNELS parameter.
     10//
     11// TODO : Register the PIDs for all KSH[i] in a ksh_pid[] array.
     12// Then calls the wait() function to block, and reactivate any child KSH process
     13// that has been deleted, using a new fork/exec.
    1414///////////////////////////////////////////////////////////////////////////////////////
    1515
     
    2020#include <pthread.h>
    2121
    22 #define NB_KSH  (NB_TXT_CHANNELS - 1)
    23 
     22#define DELAY_BETWEEN_FORK 100000
    2423
    2524//////////
     
    2726{
    2827    int     i;
    29     int     ret;           // fork return value 
    30     int     child_pid;
    31     int     status;        // used by the wait function
     28    int     ret_fork;      // fork return value 
     29    int     ret_exec;      // fork return value 
     30    int     received_pid;  // pid received from the wait syscall
     31    int     status;        // used by the wait syscall
    3232    char    string[64];
    3333
     
    3636
    3737    // create the KSH processes (one per user terminal)
    38     for( i = 0 ; i <  NB_KSH ; i++ )
     38    for( i = 1 ; i <  NB_TXT_CHANNELS ; i++ )
    3939    {
    40         // INIT process fork process CHILD
    41         ret = fork();
    4240
    43         if( ret < 0 )                            // error in fork
     41snprintf( string , 64 , "@@@ before fork / iter = %d\n" , i );
     42display_string( string );
     43
     44        // INIT process fork process CHILD[i]
     45        ret_fork = fork();
     46
     47snprintf( string , 64 , "@@@ after fork / iter = %d / ret_fork = %d\n" , i , ret_fork );
     48display_string( string );
     49
     50        if( ret_fork< 0 )   // error in fork
    4451        {
    45             // display error message on TXT0 terminal
    46             display_string( "init process cannot fork\n" );
    47 
    48             // INIT process exit
    49             exit( 1 );
    50         }
    51         else if( ret > 0 )                     // we are in INIT process
    52         {
    53             // INIT display string on kernel TXT0
    54             snprintf( string , 64 , "INIT created KSH[%d]\n" , i );
     52            // INIT display error message on TXT0 terminal
     53            snprintf( string , 64 , "init cannot fork child[%d]\n" , i );
    5554            display_string( string );
    5655
    57             // INIT process deschedule
    58             pthread_yield();
     56            // INIT exit
     57            exit( 0 );
    5958        }
    60         else                                   // we are in CHILD process
     59        else if( ret_fork == 0 )                    // we are in CHILD[i] process
    6160        {
    62             // CHILD process exec process KSH
    63             if ( exec( "/bin/user/ksh.elf" , NULL , NULL ) )  // CHILD failure
     61            // CHILD[i] process exec process KSH[i]
     62            ret_exec = exec( "/bin/user/ksh.elf" , NULL , NULL );
     63
     64            if ( ret_exec )   // error in exec             
    6465            {
    6566                // display error message on TXT0 terminal
    66                 display_string( "child process cannot exec process ksh\n" );
     67                snprintf( string , 64 , "child[%d] cannot exec ksh[%d]\n" , i , i );
     68                display_string( string );
    6769
    68                 // CHILD process exit
    69                 exit( 1 );
    70             }
    71             else                                             // child success
    72             {
    73                 // CHILD process deschedule
    74                 pthread_yield();
     70                // CHILD[i] exit
     71                // exit( 0 );
    7572            }
    7673        }
    77     }
     74        else                                      // we are in INIT process
     75        {
     76             // INIT display CHILD[i] process PID
     77             snprintf( string , 64 , "INIT forked CHILD[%d] / pid = %x\n", i , ret_fork );
     78             display_string( string );
    7879
     80             // INIT delay
     81             int     x;
     82             for( x=0 ; x<DELAY_BETWEEN_FORK ; x++) asm volatile ("nop");
     83
     84/*
     85             // INIT wait exec completion by CHILD[i]
     86             while( 1 )
     87             {
     88                 // get terminating process PID
     89                 received_pid = wait( &status );
     90
     91                 if( received_pid == ret_fork ) break;
     92                 else
     93                 {
     94                     snprintf( string , 64 ,
     95                     "expected_pid %d / received_pid %d" , ret_fork , received_pid  );
     96                     display_string( string );
     97                 }
     98             }
     99
     100*/
     101             // INIT display string on kernel TXT0
     102             snprintf( string , 64 , "INIT created KSH[%d]\n", i );
     103             display_string( string );
    79104// @@@
    80 display_string( "@@@  INIT process created all KSH processes\n" );
    81105display_process( 0 );
    82106display_sched( 0 , 0 );
    83107// @@@
     108        }
     109
     110    }
    84111
    85112    // This blocking loop is only for debug, because KSH[i] processes
    86     // should never be killed, and INIT should never exit the wait() function.
     113    // should never be killed, and INIT should never return from the wait() function.
    87114    while( 1 )
    88115    {
    89116        // block on child process termination
    90         child_pid = wait( &status );
     117        received_pid = wait( &status );
    91118
    92         // build a string to report unexpected KSH process termination
    93         snprintf( string , 64 , "KSH process %x unexpectedly terminated" , child_pid );
    94 
    95         // display string on kernel TXT0 (INIT has no TXT terminal)
     119        // display string to report unexpected KSH process termination
     120        snprintf( string , 64 , "KSH process %x unexpectedly terminated" , received_pid );
    96121        display_string( string );
    97122    }
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