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/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/exec.h>
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <vm/vm.h>
#include <vm/map.h>
#include <vm/physmem.h>
#include <machine/pcb.h>
#include <string.h>
/*
* Release the memory of the old stack
*
* @td: Target thread.
*/
static void
release_stack(struct proc *td)
{
struct pcb *pcbp = &td->pcb;
uintptr_t base = td->stack_base;
if (base >= VM_HIGHER_HALF) {
base -= VM_HIGHER_HALF;
vm_free_frame(base, PROC_STACK_PAGES);
} else {
vm_unmap(pcbp->addrsp, base, PROC_STACK_SIZE);
vm_free_frame(base, PROC_STACK_PAGES);
}
}
int
execve(struct proc *td, const struct execve_args *args)
{
int error;
struct exec_prog prog;
struct pcb *pcbp = &td->pcb;
uintptr_t stack_top, stack;
if (td == NULL || args == NULL)
return -EINVAL;
if ((error = elf64_load(args->pathname, td, &prog)) != 0)
return error;
/* Mark the thread as running exec */
td->flags |= PROC_EXEC;
/* Create the new stack */
stack = vm_alloc_frame(PROC_STACK_PAGES);
if (stack == 0) {
elf_unload(td, &prog);
return -ENOMEM;
}
/* Release the old stack if it exists */
if (td->stack_base != 0)
release_stack(td);
/* Save program state */
memcpy(&td->exec, &prog, sizeof(td->exec));
/* Set new stack and map it to userspace */
td->stack_base = stack;
vm_map(pcbp->addrsp, td->stack_base, td->stack_base,
(PROT_READ | PROT_WRITE | PROT_USER), PROC_STACK_SIZE);
prog.argp = args->argv;
prog.envp = args->envp;
stack_top = td->stack_base + (PROC_STACK_SIZE - 1);
/* Setup registers and stack */
md_td_stackinit(td, (void *)(stack_top + VM_HIGHER_HALF), &prog);
setregs(td, &prog, stack_top);
/* Done, reset flags and start the user thread */
td->flags &= ~PROC_EXEC;
md_td_kick(td);
}
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