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af03975dc1
Stopped working on self_spawn() - going to finish clone() syscall first. Arch-specific clone() library call that does ipc() and cloned child setup. - Need to finish thread_create() that satisfy clone() necessities. i.e. setting up its stack. Question: Does the pager (and thus the microkernel) have to explicitly set SP_USR? Once the call is known to be successful, the library could set it.
86 lines
1.8 KiB
C
86 lines
1.8 KiB
C
/*
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* l4/posix glue for fork()
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*
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* Copyright (C) 2008 Bahadir Balban
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <l4lib/arch/syscalls.h>
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#include <l4lib/arch/syslib.h>
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#include <l4lib/ipcdefs.h>
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#include <l4lib/utcb.h>
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#include <l4/macros.h>
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#include INC_GLUE(memory.h)
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static inline int l4_fork(void)
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{
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int err;
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/* Call pager with open() request. Check ipc error. */
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if ((err = l4_sendrecv(PAGER_TID, PAGER_TID, L4_IPC_TAG_FORK)) < 0) {
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printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, err);
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return err;
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}
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/* Check if syscall itself was successful */
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if ((err = l4_get_retval()) < 0) {
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printf("%s: OPEN Error: %d.\n", __FUNCTION__, err);
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return err;
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}
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return err;
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}
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int fork(void)
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{
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int ret = l4_fork();
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/* If error, return positive error code */
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if (ret < 0) {
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errno = -ret;
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return -1;
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}
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/* If we're a child, we need to initialise the utcb page */
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if (ret == 0)
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utcb_init();
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return ret;
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}
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extern int arch_clone(int, int);
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int clone(int (*fn)(void *), void *child_stack, int flags, void *arg, ...)
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{
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/* Set up the child stack */
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unsigned int *stack = child_stack;
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int ret;
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/* First word of new stack is arg */
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stack[-1] = (unsigned long)arg;
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/* Second word of new stack is function address */
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stack[-2] = (unsigned long)fn;
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/* Write the tag */
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l4_set_tag(L4_IPC_TAG_CLONE);
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/* Write the args as in usual ipc */
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write_mr(L4SYS_ARG0, flags);
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write_mr(L4SYS_ARG1, (unsigned long)child_stack);
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/* Perform an ipc but with different return logic. See implementation. */
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if ((ret = arch_clone(PAGER_TID, PAGER_TID)) < 0) {
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printf("%s: L4 IPC Error: %d.\n", __FUNCTION__, ret);
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return ret;
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}
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if ((ret = l4_get_retval()) < 0) {
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printf("%s: CLONE Error: %d.\n", __FUNCTION__, ret);
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return ret;
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}
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return ret;
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}
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