diff options
Diffstat (limited to 'proc.c')
-rw-r--r-- | proc.c | 257 |
1 files changed, 131 insertions, 126 deletions
@@ -17,53 +17,18 @@ int nextpid = 1; extern void forkret(void); extern void trapret(void); +static void wakeup1(void *chan); + void pinit(void) { initlock(&ptable.lock, "ptable"); } -//PAGEBREAK: 36 -// Print a process listing to console. For debugging. -// Runs when user types ^P on console. -// No lock to avoid wedging a stuck machine further. -void -procdump(void) -{ - static char *states[] = { - [UNUSED] "unused", - [EMBRYO] "embryo", - [SLEEPING] "sleep ", - [RUNNABLE] "runble", - [RUNNING] "run ", - [ZOMBIE] "zombie" - }; - int i; - struct proc *p; - char *state; - uint pc[10]; - - for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){ - if(p->state == UNUSED) - continue; - if(p->state >= 0 && p->state < NELEM(states) && states[p->state]) - state = states[p->state]; - else - state = "???"; - cprintf("%d %s %s", p->pid, state, p->name); - if(p->state == SLEEPING){ - getcallerpcs((uint*)p->context->ebp+2, pc); - for(i=0; i<10 && pc[i] != 0; i++) - cprintf(" %p", pc[i]); - } - cprintf("\n"); - } -} - - //PAGEBREAK: 32 // Look in the process table for an UNUSED proc. -// If found, change state to EMBRYO and return it. +// If found, change state to EMBRYO and initialize +// state required to run in the kernel. // Otherwise return 0. static struct proc* allocproc(void) @@ -95,7 +60,7 @@ found: p->tf = (struct trapframe*)sp; // Set up new context to start executing at forkret, - // which returns to trapret (see below). + // which returns to trapret. sp -= 4; *(uint*)sp = (uint)trapret; @@ -103,6 +68,7 @@ found: p->context = (struct context*)sp; memset(p->context, 0, sizeof *p->context); p->context->eip = (uint)forkret; + return p; } @@ -116,12 +82,10 @@ userinit(void) p = allocproc(); initproc = p; - if (!(p->pgdir = setupkvm())) + if((p->pgdir = setupkvm()) == 0) panic("userinit: out of memory?"); - if (!allocuvm(p->pgdir, 0x0, (int)_binary_initcode_size)) - panic("userinit: out of memory?"); - inituvm(p->pgdir, 0x0, _binary_initcode_start, (int)_binary_initcode_size); - p->sz = PGROUNDUP((int)_binary_initcode_size); + inituvm(p->pgdir, _binary_initcode_start, (int)_binary_initcode_size); + p->sz = PGSIZE; memset(p->tf, 0, sizeof(*p->tf)); p->tf->cs = (SEG_UCODE << 3) | DPL_USER; p->tf->ds = (SEG_UDATA << 3) | DPL_USER; @@ -142,14 +106,17 @@ userinit(void) int growproc(int n) { + uint sz; + + sz = proc->sz; if(n > 0){ - if (!allocuvm(proc->pgdir, (char *)proc->sz, n)) + if((sz = allocuvm(proc->pgdir, sz, sz + n)) == 0) return -1; } else if(n < 0){ - if (!deallocuvm(proc->pgdir, (char *)(proc->sz + n), 0 - n)) + if((sz = deallocuvm(proc->pgdir, sz, sz + n)) == 0) return -1; } - proc->sz += n; + proc->sz = sz; switchuvm(proc); return 0; } @@ -168,7 +135,7 @@ fork(void) return -1; // Copy process state from p. - if (!(np->pgdir = copyuvm(proc->pgdir, proc->sz))) { + if((np->pgdir = copyuvm(proc->pgdir, proc->sz)) == 0){ kfree(np->kstack); np->kstack = 0; np->state = UNUSED; @@ -192,6 +159,92 @@ fork(void) return pid; } +// Exit the current process. Does not return. +// An exited process remains in the zombie state +// until its parent calls wait() to find out it exited. +void +exit(void) +{ + struct proc *p; + int fd; + + if(proc == initproc) + panic("init exiting"); + + // Close all open files. + for(fd = 0; fd < NOFILE; fd++){ + if(proc->ofile[fd]){ + fileclose(proc->ofile[fd]); + proc->ofile[fd] = 0; + } + } + + iput(proc->cwd); + proc->cwd = 0; + + acquire(&ptable.lock); + + // Parent might be sleeping in wait(). + wakeup1(proc->parent); + + // Pass abandoned children to init. + for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){ + if(p->parent == proc){ + p->parent = initproc; + if(p->state == ZOMBIE) + wakeup1(initproc); + } + } + + // Jump into the scheduler, never to return. + proc->state = ZOMBIE; + sched(); + panic("zombie exit"); +} + +// Wait for a child process to exit and return its pid. +// Return -1 if this process has no children. +int +wait(void) +{ + struct proc *p; + int havekids, pid; + + acquire(&ptable.lock); + for(;;){ + // Scan through table looking for zombie children. + havekids = 0; + for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){ + if(p->parent != proc) + continue; + havekids = 1; + if(p->state == ZOMBIE){ + // Found one. + pid = p->pid; + kfree(p->kstack); + p->kstack = 0; + freevm(p->pgdir); + p->state = UNUSED; + p->pid = 0; + p->parent = 0; + p->name[0] = 0; + p->killed = 0; + release(&ptable.lock); + return pid; + } + } + + // No point waiting if we don't have any children. + if(!havekids || proc->killed){ + release(&ptable.lock); + return -1; + } + + // Wait for children to exit. (See wakeup1 call in proc_exit.) + sleep(proc, &ptable.lock); //DOC: wait-sleep + } +} + //PAGEBREAK: 42 // Per-CPU process scheduler. // Each CPU calls scheduler() after setting itself up. @@ -356,89 +409,41 @@ kill(int pid) return -1; } -// Exit the current process. Does not return. -// An exited process remains in the zombie state -// until its parent calls wait() to find out it exited. +//PAGEBREAK: 36 +// Print a process listing to console. For debugging. +// Runs when user types ^P on console. +// No lock to avoid wedging a stuck machine further. void -exit(void) +procdump(void) { + static char *states[] = { + [UNUSED] "unused", + [EMBRYO] "embryo", + [SLEEPING] "sleep ", + [RUNNABLE] "runble", + [RUNNING] "run ", + [ZOMBIE] "zombie" + }; + int i; struct proc *p; - int fd; - - if(proc == initproc) - panic("init exiting"); - - // Close all open files. - for(fd = 0; fd < NOFILE; fd++){ - if(proc->ofile[fd]){ - fileclose(proc->ofile[fd]); - proc->ofile[fd] = 0; - } - } - - iput(proc->cwd); - proc->cwd = 0; - - acquire(&ptable.lock); - - // Parent might be sleeping in wait(). - wakeup1(proc->parent); - - // Pass abandoned children to init. + char *state; + uint pc[10]; + for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){ - if(p->parent == proc){ - p->parent = initproc; - if(p->state == ZOMBIE) - wakeup1(initproc); + if(p->state == UNUSED) + continue; + if(p->state >= 0 && p->state < NELEM(states) && states[p->state]) + state = states[p->state]; + else + state = "???"; + cprintf("%d %s %s", p->pid, state, p->name); + if(p->state == SLEEPING){ + getcallerpcs((uint*)p->context->ebp+2, pc); + for(i=0; i<10 && pc[i] != 0; i++) + cprintf(" %p", pc[i]); } + cprintf("\n"); } - - // Jump into the scheduler, never to return. - proc->state = ZOMBIE; - sched(); - panic("zombie exit"); } -// Wait for a child process to exit and return its pid. -// Return -1 if this process has no children. -int -wait(void) -{ - struct proc *p; - int havekids, pid; - - acquire(&ptable.lock); - for(;;){ - // Scan through table looking for zombie children. - havekids = 0; - for(p = ptable.proc; p < &ptable.proc[NPROC]; p++){ - if(p->parent != proc) - continue; - havekids = 1; - if(p->state == ZOMBIE){ - // Found one. - pid = p->pid; - kfree(p->kstack); - p->kstack = 0; - freevm(p->pgdir); - p->state = UNUSED; - p->pid = 0; - p->parent = 0; - p->name[0] = 0; - p->killed = 0; - release(&ptable.lock); - return pid; - } - } - - // No point waiting if we don't have any children. - if(!havekids || proc->killed){ - release(&ptable.lock); - return -1; - } - - // Wait for children to exit. (See wakeup1 call in proc_exit.) - sleep(proc, &ptable.lock); //DOC: wait-sleep - } -} |