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274 volume VI os16 Script e sorgenti del kernel 275 « 1750019 | proc_table[pid].wakeup_timer--; 1750020 | if (proc_table[pid].wakeup_timer == 0) 1750021 | { 1750022 | proc_table[pid].status = PROC_READY; 1750023 | } 1750024 | } 1750025 | } 1750026 | } 1750027 | previous_time = current_time; 1750028 |} 104.9.11 kernel/proc/proc_scheduler.c Si veda la sezione 103.8.11. 1760001 |#include 1760002 |#include 1760003 |#include 1760004 |//---------------------------------------------------------------------- 1760005 |extern uint16_t _ksp; 1760006 |//---------------------------------------------------------------------- 1760007 |void 1760008 |proc_scheduler (uint16_t *sp, segment_t *segment_d) 1760009 |{ 1760010 | // 1760011 | // The process is identified from the data and stack segment. 1760012 | // 1760013 | pid_t prev; 1760014 | pid_t next; 1760015 | // 1760016 | static unsigned long int previous_clock; 1760017 | unsigned long int current_clock; 1760018 | // 1760019 | // Check if current data segments are right. 1760020 | // 1760021 | if (es () != ds () || ss () != ds ()) 1760022 | { 1760023 | k_printf ("\n"); 1760024 | k_printf ("Kernel panic: ES, DS, SS are different!\n"); 1760025 | k_exit (0); 1760026 | } 1760027 | // 1760028 | // Search the data segment inside the process table. 1760029 | // Must be done here, because the subsequent call to 1760030 | // proc_sch_signals() will remove the segment numbers 1760031 | // from a zombie process. 1760032 | // 1760033 | prev = proc_find (*segment_d); 1760034 | // 1760035 | // Take care of sleeping processes: wake up if sleeping time 1760036 | // elapsed. 1760037 | // 1760038 | proc_sch_timers (); 1760039 | // 1760040 | // Take care of pending signals. 1760041 | // 1760042 | proc_sch_signals (); 1760043 | // 1760044 | // Take care input from terminals. 1760045 | // 1760046 | proc_sch_terminals (); 1760047 | // 1760048 | // Update the CPU time usage. 1760049 | // 1760050 | current_clock = k_clock (); 1760051 | proc_table[prev].usage += current_clock - previous_clock; 1760052 | previous_clock = current_clock; 1760053 | // 1760054 | // Scan for a next process. 1760055 | // 1760056 | for (next = prev+1; next != prev; next++) 1760057 | { 1760058 | if (next >= PROCESS_MAX) 1760059 | { 1760060 | next = -1; // At the next loop, ‘next’ will be zero. 1760061 | continue; 1760062 | } 1760063 | if (proc_table[next].status == PROC_EMPTY) 1760064 | { 1760065 | continue; 1760066 | } 1760067 | else if (proc_table[next].status == PROC_CREATED) 1760068 | { 1760069 | continue; 1760070 | } 1760071 | else if (proc_table[next].status == PROC_READY) 1760072 | { 1760073 | if (proc_table[prev].status == PROC_RUNNING) 1760074 | { 1760075 | proc_table[prev].status = PROC_READY; 1760076 | } 1760077 | proc_table[prev].sp = *sp; 1760078 | proc_table[next].status = PROC_RUNNING; 1760079 | proc_table[next].ret = 0; 1760080 | *segment_d = proc_table[next].segment_d; 1760081 | *sp = proc_table[next].sp; 1760082 | break; 1760083 | } 1760084 | else if (proc_table[next].status == PROC_RUNNING) 1760085 | { 1760086 | if (proc_table[prev].status == PROC_RUNNING) 1760087 | { 1760088 | k_printf ("Kernel alert: process %i ", prev); 1760089 | k_printf ("and %i \"running\"!\r", next); 1760090 | proc_table[prev].status = PROC_READY; 1760091 | } 1760092 | proc_table[prev].sp = *sp; 1760093 | proc_table[next].status = PROC_RUNNING; 1760094 | proc_table[next].ret = 0; 1760095 | *segment_d = proc_table[next].segment_d; 1760096 | *sp = proc_table[next].sp; 1760097 | break; 1760098 | } 1760099 | else if (proc_table[next].status == PROC_SLEEPING) 1760100 | { 1760101 | continue; 1760102 | } 1760103 | else if (proc_table[next].status == PROC_ZOMBIE) 1760104 | { 1760105 | continue; 1760106 | } 1760107 | } 1760108 | // 1760109 | // Check again if the next process is set to running, otherwise set 1760110 | // the kernel to such value! 1760111 | // 1760112 | next = proc_find (*segment_d); 1760113 | if (proc_table[next].status != PROC_RUNNING) 1760114 | { 1760115 | proc_table[0].status = PROC_RUNNING; 1760116 | *segment_d = proc_table[0].segment_d; 1760117 | *sp = proc_table[0].sp; 1760118 | } 1760119 | // 1760120 | // Save kernel stack pointer. 1760121 | // 1760122 | _ksp = proc_table[0].sp; 1760123 | // 1760124 | // At the end, must inform the PIC 1, with message «EOI». 1760125 | // 1760126 | out_8 (0x20, 0x20); 1760127 |} 104.9.12 kernel/proc/proc_sig_chld.c Si veda la sezione 103.8.12. 1770001 |#include 1770002 |//---------------------------------------------------------------------- 1770003 |void 1770004 |proc_sig_chld (pid_t parent, int sig) 1770005 |{ 1770006 | pid_t child; 1770007 | // 1770008 | // Please note that ‘sig’ should be SIGCHLD and nothing else. 1770009 | // So, the following test, means to verify if the parent process 1770010 | // has received a SIGCHLD already. 1770011 | // 1770012 | if (proc_sig_status (parent, sig)) 1770013 | { 1770014 | if ( (!proc_sig_ignore (parent, sig)) 1770015 | && (proc_table[parent].status == PROC_SLEEPING) 1770016 | && (proc_table[parent].wakeup_events & WAKEUP_EVENT_SIGNAL) 1770017 | && (proc_table[parent].wakeup_signal == sig)) 1770018 | { 1770019 | // 1770020 | // The signal is not ignored from the parent process; 1770021 | // the parent process is sleeping; 1770022 | // the parent process is waiting for a signal; 1770023 | // the parent process is waiting for current signal. 1770024 | // So, just wake it up. 1770025 | // 1770026 | proc_table[parent].status = PROC_READY; 1770027 | proc_table[parent].wakeup_events ^= WAKEUP_EVENT_SIGNAL; 1770028 | proc_table[parent].wakeup_signal = 0; 1770029 | } 1770030 | else 1770031 | { 1770032 | // 1770033 | // All other cases, means to remove all dead children. 1770034 | // 1770035 | for (child = 1; child < PROCESS_MAX; child++) 1770036 | { 1770037 | if ( proc_table[child].ppid == parent 1770038 | && proc_table[child].status == PROC_ZOMBIE) 1770039 | { 1770040 | proc_available (child); 1770041 | } 1770042 | } 1770043 | } 1770044 | proc_sig_off (parent, sig); 1770045 | } 1770046 |} 104.9.13 kernel/proc/proc_sig_cont.c Si veda la sezione 103.8.13. 1780001 |#include 1780002 |//---------------------------------------------------------------------- 1780003 |void 1780004 |proc_sig_cont (pid_t pid, int sig) 1780005 |{ 1780006 | // 1780007 | // The value for argument ‘sig’ should be SIGCONT. 1780008 | // 1780009 | if (proc_sig_status (pid, sig)) 1780010 | { 1780011 | if (proc_sig_ignore (pid, sig)) 1780012 | { 1780013 | proc_sig_off (pid, sig); 1780014 | } 1780015 | else 1780016 | { 1780017 | proc_table[pid].status = PROC_READY; 1780018 | proc_sig_off (pid, sig); 1780019 | } 1780020 | } 1780021 |} 104.9.14 kernel/proc/proc_sig_core.c Si veda la sezione 103.8.14. 1790001 |#include 1790002 |//---------------------------------------------------------------------- 1790003 |void 1790004 |proc_sig_core (pid_t pid, int sig) 1790005 |{ « « «
276 volume VI os16 Script e sorgenti del kernel 277 « « « « 1790006 | addr_t address_i; 1790007 | addr_t address_d; 1790008 | size_t size_i; 1790009 | size_t size_d; 1790010 | // 1790011 | if (proc_sig_status (pid, sig)) 1790012 | { 1790013 | if (proc_sig_ignore (pid, sig)) 1790014 | { 1790015 | proc_sig_off (pid, sig); 1790016 | } 1790017 | else 1790018 | { 1790019 | // 1790020 | // Save process addresses and sizes (might be useful if 1790021 | // we want to try to exit the process before core dump. 1790022 | // 1790023 | address_i = proc_table[pid].address_i; 1790024 | address_d = proc_table[pid].address_d; 1790025 | size_i = proc_table[pid].size_i; 1790026 | size_d = proc_table[pid].size_d; 1790027 | // 1790028 | // Core dump: the process who formally writes the file 1790029 | // is the terminating one. 1790030 | // 1790031 | if (address_d == address_i) 1790032 | { 1790033 | proc_dump_memory (pid, address_i, size_i, "core"); 1790034 | } 1790035 | else 1790036 | { 1790037 | proc_dump_memory (pid, address_i, size_i, "core.i"); 1790038 | proc_dump_memory (pid, address_d, size_d, "core.d"); 1790039 | } 1790040 | // 1790041 | // The signal, translated to negative, is returned (but 1790042 | // the effective value received by the application will 1790043 | // be cutted, leaving only the low 8 bit). 1790044 | // 1790045 | proc_sys_exit (pid, -sig); 1790046 | } 1790047 | } 1790048 |} 104.9.15 kernel/proc/proc_sig_ignore.c Si veda la sezione 103.8.15. 1800001 |#include 1800002 |//---------------------------------------------------------------------- 1800003 |int 1800004 |proc_sig_ignore (pid_t pid, int sig) 1800005 |{ 1800006 | unsigned long int flag = 1L
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