source: trunk/user/init/init.c @ 581

Last change on this file since 581 was 581, checked in by alain, 2 years ago

1) Improve the busylock debug infrastructure.
2) introduce a non-distributed, but portable implementation for the pthread_barrier.

File size: 6.1 KB
Line 
1///////////////////////////////////////////////////////////////////////////////////////
2// File   :  init.c
3// Date   :  January 2018
4// Author :  Alain Greiner
5///////////////////////////////////////////////////////////////////////////////////////
6// 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).
9// Then calls the wait() function to block, and reactivate any child KSH process
10// that has been deleted, using a new fork/exec.
11// It includes the hard_config.h file to get th NB_TXT_CHANNELS parameter.
12///////////////////////////////////////////////////////////////////////////////////////
13
14#include <hard_config.h>
15#include <unistd.h>
16#include <stdlib.h>
17#include <stdio.h>
18#include <pthread.h>
19#include <almosmkh.h>
20#include <hal_macros.h>
21#include <sys/wait.h>
22
23#define DEBUG_PROCESS_INIT    1
24
25// TODO improve the get_config() syscall to return nb_txt_channels
26// and avoid the hard_config include [AG]
27
28// TODO introduce a communication channel between INIT and KSH
29// to allow KSH to signal INIT the exec completion.
30
31////////////////
32int main( void )
33{
34    int           i;
35    int           ret_fork;      // fork return value 
36    int           ret_exec;      // exec return value 
37    int           rcv_pid;       // pid received from the wait syscall
38    int           status;        // used by the wait syscall
39    char          string[64];    // log messages on kernel TXT0
40
41#if DEBUG_PROCESS_INIT
42display_string("[INIT] process enters");
43#endif
44
45    // check number of TXT channels
46    if( NB_TXT_CHANNELS < 2 )
47    {
48        printf("\n[ERROR] in init process : number of TXT channels must be larger than 1\n");
49        exit( EXIT_FAILURE );
50    }
51
52    // create the KSH processes (one per user terminal)
53    for( i = 1 ; i <  NB_TXT_CHANNELS ; i++ )
54    {
55        // INIT process fork process CHILD[i]
56        ret_fork = fork();
57
58        if( ret_fork < 0 )   // error in fork
59        {
60            // INIT display error message 
61            snprintf( string , 64 , "[INIT ERROR] cannot fork child[%d] => suicide" , i );
62            display_string( string );
63
64            // INIT suicide
65            exit( 0 );
66        }
67        else if( ret_fork == 0 )                    // we are in CHILD[i] process
68        {
69            // CHILD[i] process exec process KSH[i]
70            ret_exec = execve( "/bin/user/ksh.elf" , NULL , NULL ); 
71
72            if ( ret_exec )   // error in exec             
73            {
74                // CHILD[i] display error message
75                snprintf( string , 64 , 
76                "[INIT ERROR] CHILD[%d] cannot exec KSH / ret_exec = %d" , i , ret_exec );
77                display_string( string );
78            }
79        }
80        else                                      // we are in INIT process
81        {
82            // INIT display CHILD[i] process PID
83            snprintf( string , 64 , "[INIT] created KSH[%d] / pid = %x", i , ret_fork ); 
84            display_string( string );
85        }
86    } 
87 
88#if DEBUG_PROCESS_INIT
89{
90    unsigned int  x_size;        // number of clusters in a row
91    unsigned int  y_size;        // number of clusters in a column
92    unsigned int  ncores;        // number of cores per cluster
93    unsigned int  x;             // cluster x coordinate
94    unsigned int  y;             // cluster y coordinate
95    unsigned int  cxy;           // cluster identifier
96    unsigned int  lid;           // core local index
97
98    // get hardware config
99    get_config( &x_size , &y_size , &ncores );
100
101    // INIT displays processes and threads in all clusters
102    for( x = 0 ; x < x_size ; x++ )
103    {
104        for( y = 0 ; y < x_size ; y++ )
105        {
106            cxy = HAL_CXY_FROM_XY( x , y );
107            display_cluster_processes( cxy );
108            for( lid = 0 ; lid < ncores ; lid++ )
109            { 
110                display_sched( cxy , lid );
111            }
112        }
113    }
114}
115#endif
116
117    // This loop detects the termination of the KSH[i] processes,
118    // and recreate a new KSH[i] process when required.
119    while( 1 )
120    {
121        // block on child processes termination
122        rcv_pid = wait( &status );
123
124        if( WIFSTOPPED( status ) )                         // stopped => unblock it
125        {
126            // display string to report unexpected KSH process block
127            snprintf( string , 64 , "[INIT] KSH process %x stopped => unblock it" , rcv_pid );
128            display_string( string ); 
129
130            // TODO : unblock KSH [AG]
131
132        }  // end KSH stopped handling
133
134        if( WIFSIGNALED( status ) || WIFEXITED( status ) )  // killed => recreate it
135        {
136            // display string to report KSH process termination
137            snprintf( string , 64 , "[INIT] KSH process %x terminated => recreate", rcv_pid );
138            display_string( string ); 
139
140            // INIT process fork a new CHILD process
141            ret_fork = fork();
142
143            if( ret_fork < 0 )                          // error in fork
144            {
145                // INIT display error message
146                snprintf( string , 64 , "[INIT ERROR] cannot fork child => suicide");
147                display_string( string );
148
149                // INIT suicide
150                exit( 0 );
151            }
152            else if( ret_fork == 0 )                    // we are in CHILD process
153            {
154                // CHILD process exec process KSH
155                ret_exec = execve( "/bin/user/ksh.elf" , NULL , NULL ); 
156
157                if ( ret_exec )   // error in exec             
158                {
159                    // CHILD display error message on TXT0 terminal
160                    snprintf( string , 64 , "[INIT ERROR] CHILD cannot exec KSH" );
161                    display_string( string );
162                }
163            }
164            else                                       // we are in INIT process
165            {
166                // INIT display new KSH process PID
167                snprintf( string , 64 , "[INIT] re-created KSH / pid = %x", ret_fork ); 
168                display_string( string );
169            }
170        } // end KSH kill handling
171
172    }  // end while waiting KSH[i] termination
173
174} // end main()
175
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