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Kernel: Pass process arguments directly on the stack.

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Get rid of the convoluted get_arguments and get_environment syscalls.
This patch also adds a simple /bin/env that just prints its environment.
This commit is contained in:
Andreas Kling 2019-02-22 01:55:22 +01:00
parent e969419202
commit 6d3e12899b
9 changed files with 59 additions and 66 deletions
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84
Kernel/Process.cpp
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@ -223,9 +223,6 @@ Process* Process::fork(RegisterDump& regs)
dbgprintf("fork: child=%p\n", child);
#endif
child->m_initial_arguments = m_initial_arguments;
child->m_initial_environment = m_initial_environment;
for (auto& region : m_regions) {
#ifdef FORK_DEBUG
dbgprintf("fork: cloning Region{%p} \"%s\" L%x\n", region.ptr(), region->name.characters(), region->laddr().get());
@ -426,8 +423,46 @@ void Process::make_userspace_stack(Vector<String> arguments, Vector<String> envi
m_stack_top3 = region->laddr().offset(default_userspace_stack_size).get();
m_tss.esp = m_stack_top3;
m_initial_arguments = move(arguments);
m_initial_environment = move(environment);
char* stack_base = (char*)region->laddr().get();
int argc = arguments.size();
char** argv = (char**)stack_base;
char** env = argv + arguments.size() + 1;
char* bufptr = stack_base + (sizeof(char*) * (arguments.size() + 1)) + (sizeof(char*) * (environment.size() + 1));
size_t total_blob_size = 0;
for (auto& a : arguments)
total_blob_size += a.length() + 1;
for (auto& e : environment)
total_blob_size += e.length() + 1;
size_t total_meta_size = sizeof(char*) * (arguments.size() + 1) + sizeof(char*) * (environment.size() + 1);
// FIXME: It would be better if this didn't make us panic.
ASSERT((total_blob_size + total_meta_size) < default_userspace_stack_size);
for (size_t i = 0; i < arguments.size(); ++i) {
argv[i] = bufptr;
memcpy(bufptr, arguments[i].characters(), arguments[i].length());
bufptr += arguments[i].length();
*(bufptr++) = '\0';
printf("argv[%u] = %p (%s)\n", i, argv[i], argv[i]);
}
argv[arguments.size()] = nullptr;
for (size_t i = 0; i < environment.size(); ++i) {
env[i] = bufptr;
memcpy(bufptr, environment[i].characters(), environment[i].length());
bufptr += environment[i].length();
*(bufptr++) = '\0';
printf("env[%u] = %p (%s)\n", i, env[i], env[i]);
}
env[environment.size()] = nullptr;
// NOTE: The stack needs to be 16-byte aligned.
push_value_on_stack((dword)env);
push_value_on_stack((dword)argv);
push_value_on_stack((dword)argc);
push_value_on_stack(0);
}
int Process::exec(String path, Vector<String> arguments, Vector<String> environment)
@ -529,45 +564,6 @@ Process* Process::create_user_process(const String& path, uid_t uid, gid_t gid,
return process;
}
int Process::sys$get_environment(char*** environ)
{
auto* region = allocate_region(LinearAddress(), PAGE_SIZE, "environ");
if (!region)
return -ENOMEM;
MM.map_region(*this, *region);
char* envpage = (char*)region->laddr().get();
*environ = (char**)envpage;
char* bufptr = envpage + (sizeof(char*) * (m_initial_environment.size() + 1));
for (size_t i = 0; i < m_initial_environment.size(); ++i) {
(*environ)[i] = bufptr;
memcpy(bufptr, m_initial_environment[i].characters(), m_initial_environment[i].length());
bufptr += m_initial_environment[i].length();
*(bufptr++) = '\0';
}
(*environ)[m_initial_environment.size()] = nullptr;
return 0;
}
int Process::sys$get_arguments(int* argc, char*** argv)
{
auto* region = allocate_region(LinearAddress(), PAGE_SIZE, "argv");
if (!region)
return -ENOMEM;
MM.map_region(*this, *region);
char* argpage = (char*)region->laddr().get();
*argc = m_initial_arguments.size();
*argv = (char**)argpage;
char* bufptr = argpage + (sizeof(char*) * (m_initial_arguments.size() + 1));
for (size_t i = 0; i < m_initial_arguments.size(); ++i) {
(*argv)[i] = bufptr;
memcpy(bufptr, m_initial_arguments[i].characters(), m_initial_arguments[i].length());
bufptr += m_initial_arguments[i].length();
*(bufptr++) = '\0';
}
(*argv)[m_initial_arguments.size()] = nullptr;
return 0;
}
Process* Process::create_kernel_process(String&& name, void (*e)())
{
auto* process = new Process(move(name), (uid_t)0, (gid_t)0, (pid_t)0, Ring0);