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exec: Use check_elf_image()

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This allows exec to recover if an error should occur when loading the executable.

Thus, the calling process will be notified instead of killed.
This commit is contained in:
apio 2022-10-12 18:43:48 +02:00
parent 1a54342454
commit 8a7ddfca80
1 changed files with 18 additions and 22 deletions
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40
kernel/src/sys/exec.cpp
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@ -26,6 +26,18 @@ void sys_exec(Context* context, const char* pathname)
return; return;
} }
if (program->type == VFS_DIRECTORY)
{
context->rax = -EISDIR;
return;
}
if (ELFLoader::check_elf_image(program) < 0)
{
context->rax = -EINVAL; // FIXME: Should be ENOEXEC.
return;
}
uint64_t allocated_stack = (uint64_t)MemoryManager::get_pages(TASK_PAGES_IN_STACK, MAP_READ_WRITE | MAP_USER); uint64_t allocated_stack = (uint64_t)MemoryManager::get_pages(TASK_PAGES_IN_STACK, MAP_READ_WRITE | MAP_USER);
if (!allocated_stack) if (!allocated_stack)
{ {
@ -33,28 +45,6 @@ void sys_exec(Context* context, const char* pathname)
return; return;
} }
char* kpathname = strdup(
pathname); // Since we are going to free the original task's memory, we cannot use anything coming from it.
// FIXME: This should be done later, but since there is a very high chance that loading the executed program's
// ELF image will overwrite ours, we have to do it here.
ELFLoader::release_elf_image(Scheduler::current_task()->image);
// FIXME: Check the ELF image is valid before loading it into memory. This will allow us to first check, then free
// the previous image, then load, which should reduce the chances of loading failing to almost zero.
ELFImage* image = ELFLoader::load_elf_from_filesystem(kpathname);
if (!image)
{
MemoryManager::release_pages((void*)allocated_stack, TASK_PAGES_IN_STACK);
Scheduler::current_task()->image = nullptr;
kfree(kpathname);
kerrorln("exec(): ERROR: Failed to load program. Previous program has already been freed, thus cannot "
"return to it.");
return Scheduler::task_exit(context, -255);
}
kfree(kpathname);
Interrupts::disable(); Interrupts::disable();
ASSERT(!Interrupts::are_enabled()); // This part is pretty sensitive. ASSERT(!Interrupts::are_enabled()); // This part is pretty sensitive.
@ -63,6 +53,12 @@ void sys_exec(Context* context, const char* pathname)
// At this point, pretty much nothing can fail. // At this point, pretty much nothing can fail.
ELFLoader::release_elf_image(Scheduler::current_task()->image);
ELFImage* image = ELFLoader::load_elf_from_vfs(program);
ASSERT(image); // If check_elf_image succeeded, load_elf_from_vfs MUST succeed, unless something has gone terribly
// wrong.
MemoryManager::release_pages((void*)task->allocated_stack, TASK_PAGES_IN_STACK); MemoryManager::release_pages((void*)task->allocated_stack, TASK_PAGES_IN_STACK);
task->allocated_stack = allocated_stack; task->allocated_stack = allocated_stack;