source: trunk/user/init/init.c @ 468

Last change on this file since 468 was 457, checked in by alain, 6 years ago

This version modifies the exec syscall and fixes a large number of small bugs.
The version number has been updated (0.1)

File size: 6.5 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 <sys/wait.h>
21
22#define DEBUG_PROCESS_INIT    0
23
24// TODO make the cxy computation portable
25// and avoid this TSAR specific define [AG]
26
27#define CXY_FROM_XY( x , y )  ((x<<4) + y)
28
29// TODO improve the get_config() syscall to return nb_txt_channels
30// and avoid the hard_config include [AG]
31
32//////////
33int main()
34{
35    int           i;
36    int           ret_fork;      // fork return value 
37    int           ret_exec;      // exec return value 
38    int           rcv_pid;       // pid received from the wait syscall
39    int           status;        // used by the wait syscall
40    char          string[64];    // log messages on kernel TXT0
41
42    // check number of TXT channels
43    if( NB_TXT_CHANNELS < 2 )
44    {
45        printf("\n[ERROR] in init process : number of TXT channels must be larger than 1\n");
46        exit( EXIT_FAILURE );
47    }
48
49    // create the KSH processes (one per user terminal)
50    for( i = 1 ; i <  NB_TXT_CHANNELS ; i++ )
51    {
52
53#if DEBUG_PROCESS_INIT
54snprintf( string , 64 , "[INIT] start child[%d] creation" , i );
55display_string( string );
56#endif
57
58        // INIT process fork process CHILD[i]
59        ret_fork = fork();
60
61        if( ret_fork < 0 )   // error in fork
62        {
63            // INIT display error message 
64            snprintf( string , 64 , "[INIT ERROR] cannot fork child[%d] => suicide" , i );
65            display_string( string );
66
67            // INIT suicide
68            exit( 0 );
69        }
70        else if( ret_fork == 0 )                    // we are in CHILD[i] process
71        {
72            // CHILD[i] process exec process KSH[i]
73            ret_exec = execve( "/bin/user/ksh.elf" , NULL , NULL ); 
74
75            if ( ret_exec )   // error in exec             
76            {
77                // CHILD[i] display error message
78                snprintf( string , 64 , 
79                "[INIT ERROR] CHILD[%d] cannot exec KSH / ret_exec = %d" , i , ret_exec );
80                display_string( string );
81            }
82        }
83        else                                      // we are in INIT process
84        {
85            // INIT display CHILD[i] process PID
86            snprintf( string , 64 , "[INIT] created KSH[%d] / pid = %x", i , ret_fork ); 
87            display_string( string );
88        }
89    } 
90 
91#if DEBUG_PROCESS_INIT
92unsigned int  x_size;        // number of clusters in a row
93unsigned int  y_size;        // number of clusters in a column
94unsigned int  ncores;        // number of cores per cluster
95unsigned int  x;             // cluster x coordinate
96unsigned int  y;             // cluster y coordinate
97unsigned int  cxy;           // cluster identifier
98unsigned int  lid;           // core local index
99
100// get hardware config
101get_config( &x_size , &y_size , &ncores );
102   
103// INIT displays processes and threads in all clusters
104for( x = 0 ; x < x_size ; x++ )
105{
106    for( y = 0 ; y < y_size ; y++ )
107    {
108        cxy = CXY_FROM_XY( x , y );
109        display_cluster_processes( cxy );
110        for( lid = 0 ; lid < ncores ; lid++ )
111        { 
112            display_sched( cxy , lid );
113        }
114    }
115}
116#endif
117
118    // This loop detects the termination of the KSH[i] processes,
119    // and recreate a new KSH[i] process when required.
120    while( 1 )
121    {
122        // block on child processes termination
123        rcv_pid = wait( &status );
124
125        if( WIFSTOPPED( status ) )                         // stopped => unblock it
126        {
127            // display string to report unexpected KSH process block
128            snprintf( string , 64 , "[INIT] KSH process %x stopped => unblock it" , rcv_pid );
129            display_string( string ); 
130
131            // TODO : unblock KSH [AG]
132
133        }  // end KSH stopped handling
134
135        if( WIFSIGNALED( status ) || WIFEXITED( status ) )  // killed => recreate it
136        {
137            // display string to report KSH process termination
138            snprintf( string , 64 , "[INIT] KSH process %x terminated => recreate", rcv_pid );
139            display_string( string ); 
140
141            // INIT process fork a new CHILD process
142            ret_fork = fork();
143
144            if( ret_fork < 0 )                          // error in fork
145            {
146                // INIT display error message
147                snprintf( string , 64 , "[INIT ERROR] cannot fork child => suicide");
148                display_string( string );
149
150                // INIT suicide
151                exit( 0 );
152            }
153            else if( ret_fork == 0 )                    // we are in CHILD process
154            {
155                // CHILD process exec process KSH
156                ret_exec = execve( "/bin/user/ksh.elf" , NULL , NULL ); 
157
158                if ( ret_exec )   // error in exec             
159                {
160                    // CHILD display error message on TXT0 terminal
161                    snprintf( string , 64 , "[INIT ERROR] CHILD cannot exec KSH" );
162                    display_string( string );
163                }
164            }
165            else                                       // we are in INIT process
166            {
167                // INIT display new KSH process PID
168                snprintf( string , 64 , "[INIT] re-created KSH / pid = %x", ret_fork ); 
169                display_string( string );
170            }
171        } // end KSH kill handling
172
173#if DEBUG_PROCESS_INIT
174
175        // INIT displays processes and threads in all clusters
176        for( x = 0 ; x < x_size ; x++ )
177        {
178            for( y = 0 ; y < y_size ; y++ )
179            {
180                cxy = CXY_FROM_XY( x , y );
181                display_cluster_processes( cxy );
182                for( lid = 0 ; lid < ncores ; lid++ )
183                { 
184                    display_sched( cxy , lid );
185                }
186            }
187        }
188
189#endif
190
191    }  // end while waiting KSH[i] termination
192
193} // end main()
194
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