75 lines
1.6 KiB
C
75 lines
1.6 KiB
C
#include <kernel/process.h>
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#include <kernel/scheduler.h>
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#include <kernel/devices/earlyterm.h>
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#include <kernel/util/atomic.h>
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pid_t sys_waitpid(pid_t pid, int *wstatus, int options)
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{
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extern struct process *process_current;
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struct process **proc;
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pid_t ret;
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// Check useless wait
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if (process_current->child == NULL) {
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earlyterm_write("waitpid: no child\n");
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DBG_WAIT;
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return (-1);
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}
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//TODO: handle options
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(void)options;
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// Wait util one of its children specified by PID
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// has changed state
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while (1)
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{
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// Start atomic operation
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atomic_start();
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// Find childs to check
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proc = &process_current->child;
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while (*proc != NULL)
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{
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// Check terminated child
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if ((*proc)->sched_task->status == SCHED_TASK_ZOMBIE &&
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((pid < -1 && (*proc)->pgid == -pid)
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|| pid == -1
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|| (pid == 0 && (*proc)->pgid == process_current->pgid)
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|| (pid > 0 && (*proc)->pid == pid)))
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{
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// Change the child process state
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// @note: internal address used to determine if
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// the process is alive or not
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(*proc)->parent = (void*)0xdeadbeef;
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// Get the child process PID and stat_loc
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ret = (*proc)->pid;
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*wstatus = (*proc)->__stat_loc;
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// Remove process form the child list
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*proc = (*proc)->sibling;
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// Stop atomic operation and return
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atomic_stop();
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return (ret);
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}
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// Get next child process
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proc = &(*proc)->sibling;
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}
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// Force process to sleep
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// TODO:
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// * Force schedule !!
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// * change the niciess of the process !!
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// * wait SIGCHLD !!!!
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//
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// Stop atomic operation and wait
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atomic_stop();
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__asm__ volatile ("sleep; nop");
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}
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// Error
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return (-1);
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}
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