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Kernel: add basic support for environment variables 

exec functions will search files from PATH
This commit is contained in:
Bananymous 2023-06-05 21:53:37 +03:00
parent 6aff459e1c
commit 064ce568c2
5 changed files with 137 additions and 37 deletions
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8
kernel/include/kernel/Process.h
View File

@ -27,7 +27,7 @@ namespace Kernel
public:
using entry_t = Thread::entry_t;
struct userspace_entry_t
struct userspace_info_t
{
uintptr_t entry { 0 };
int argc { 0 };
@ -49,7 +49,7 @@ namespace Kernel
pid_t pid() const { return m_pid; }
static BAN::ErrorOr<LibELF::ELF*> load_elf_for_exec(BAN::StringView);
static BAN::ErrorOr<LibELF::ELF*> load_elf_for_exec(BAN::StringView file_path, const BAN::String& cwd, const BAN::Vector<BAN::StringView>& path_env);
BAN::ErrorOr<Process*> fork(uintptr_t rsp, uintptr_t rip);
BAN::ErrorOr<void> exec(BAN::StringView path, const char* const* argv, const char* const* envp);
@ -87,7 +87,7 @@ namespace Kernel
PageTable& page_table() { return m_page_table ? *m_page_table : PageTable::kernel(); }
const userspace_entry_t& userspace_entry() const { return m_userspace_entry; }
const userspace_info_t& userspace_info() const { return m_userspace_info; }
private:
Process(pid_t);
@ -132,7 +132,7 @@ namespace Kernel
BAN::Vector<BAN::UniqPtr<FixedWidthAllocator>> m_fixed_width_allocators;
BAN::UniqPtr<GeneralAllocator> m_general_allocator;
userspace_entry_t m_userspace_entry;
userspace_info_t m_userspace_info;
ExitStatus m_exit_status;
BAN::UniqPtr<PageTable> m_page_table;

111
kernel/kernel/Process.cpp
View File

@ -46,7 +46,7 @@ namespace Kernel
BAN::ErrorOr<Process*> Process::create_userspace(BAN::StringView path)
{
auto* elf = TRY(load_elf_for_exec(path));
auto* elf = TRY(load_elf_for_exec(path, "/"sv, {}));
auto* process = create_process();
MUST(process->m_working_directory.push_back('/'));
@ -55,19 +55,28 @@ namespace Kernel
process->load_elf(*elf);
char** argv = nullptr;
char** envp = nullptr;
{
PageTableScope _(process->page_table());
argv = (char**)MUST(process->allocate(sizeof(char**) * 2));
argv[0] = (char*)MUST(process->allocate(path.size() + 1));
memcpy(argv[0], path.data(), path.size());
argv[0][path.size()] = '\0';
argv[1] = nullptr;
BAN::StringView env1 = "PATH=/bin:/usr/bin"sv;
envp = (char**)MUST(process->allocate(sizeof(char**) * 2));
envp[0] = (char*)MUST(process->allocate(env1.size() + 1));
memcpy(envp[0], env1.data(), env1.size());
envp[0][env1.size()] = '\0';
envp[1] = nullptr;
}
process->m_userspace_entry.argc = 1;
process->m_userspace_entry.argv = argv;
process->m_userspace_entry.envp = (char**)0x69696969;
process->m_userspace_entry.entry = elf->file_header_native().e_entry;
process->m_userspace_info.argc = 1;
process->m_userspace_info.argv = argv;
process->m_userspace_info.envp = envp;
process->m_userspace_info.entry = elf->file_header_native().e_entry;
delete elf;
@ -155,9 +164,54 @@ namespace Kernel
return {};
}
BAN::ErrorOr<LibELF::ELF*> Process::load_elf_for_exec(BAN::StringView path)
BAN::ErrorOr<LibELF::ELF*> Process::load_elf_for_exec(BAN::StringView file_path, const BAN::String& cwd, const BAN::Vector<BAN::StringView>& path_env)
{
auto elf_or_error = LibELF::ELF::load_from_file(path);
if (file_path.empty())
return BAN::Error::from_errno(ENOENT);
BAN::String absolute_path;
if (file_path.front() == '/')
{
// We have an absolute path
TRY(absolute_path.append(file_path));
}
else if (file_path.front() == '.' || file_path.contains('/'))
{
// We have a relative path
TRY(absolute_path.append(cwd));
TRY(absolute_path.push_back('/'));
TRY(absolute_path.append(file_path));
}
else
{
// We have neither relative or absolute path,
// search from PATH environment
for (auto path_part : path_env)
{
if (path_part.empty())
continue;
if (path_part.front() != '/')
{
TRY(absolute_path.append(cwd));
TRY(absolute_path.push_back('/'));
}
TRY(absolute_path.append(path_part));
TRY(absolute_path.push_back('/'));
TRY(absolute_path.append(file_path));
if (!VirtualFileSystem::get().file_from_absolute_path(absolute_path, true).is_error())
break;
absolute_path.clear();
}
if (absolute_path.empty())
return BAN::Error::from_errno(ENOENT);
}
auto elf_or_error = LibELF::ELF::load_from_file(absolute_path);
if (elf_or_error.is_error())
{
if (elf_or_error.error().get_error_code() == EINVAL)
@ -195,7 +249,7 @@ namespace Kernel
forked->m_open_files = m_open_files;
forked->m_userspace_entry = m_userspace_entry;
forked->m_userspace_info = m_userspace_info;
for (auto* mapped_range : m_mapped_ranges)
MUST(forked->m_mapped_ranges.push_back(mapped_range->clone(forked->page_table())));
@ -219,16 +273,19 @@ namespace Kernel
BAN::ErrorOr<void> Process::exec(BAN::StringView path, const char* const* argv, const char* const* envp)
{
BAN::Vector<BAN::String> str_argv;
while (argv && *argv)
if (str_argv.emplace_back(*argv++).is_error())
return BAN::Error::from_errno(ENOMEM);
for (int i = 0; argv && argv[i]; i++)
TRY(str_argv.emplace_back(argv[i]));
BAN::Vector<BAN::StringView> path_env;
BAN::Vector<BAN::String> str_envp;
while (envp && *envp)
if (str_envp.emplace_back(*envp++).is_error())
return BAN::Error::from_errno(ENOMEM);
for (int i = 0; envp && envp[i]; i++)
{
TRY(str_envp.emplace_back(envp[i]));
if (strncmp(envp[i], "PATH=", 5) == 0)
path_env = TRY(BAN::StringView(envp[i]).substring(5).split(':'));
}
auto* elf = TRY(load_elf_for_exec(path));
auto* elf = TRY(load_elf_for_exec(path, TRY(working_directory()), path_env));
LockGuard lock_guard(m_lock);
@ -243,7 +300,7 @@ namespace Kernel
load_elf(*elf);
m_userspace_entry.entry = elf->file_header_native().e_entry;
m_userspace_info.entry = elf->file_header_native().e_entry;
delete elf;
@ -252,17 +309,27 @@ namespace Kernel
{
PageTableScope _(page_table());
m_userspace_entry.argv = (char**)MUST(allocate(sizeof(char**) * (str_argv.size() + 1)));
m_userspace_info.argv = (char**)MUST(allocate(sizeof(char**) * (str_argv.size() + 1)));
for (size_t i = 0; i < str_argv.size(); i++)
{
m_userspace_entry.argv[i] = (char*)MUST(allocate(str_argv[i].size() + 1));
memcpy(m_userspace_entry.argv[i], str_argv[i].data(), str_argv[i].size());
m_userspace_entry.argv[i][str_argv[i].size()] = '\0';
m_userspace_info.argv[i] = (char*)MUST(allocate(str_argv[i].size() + 1));
memcpy(m_userspace_info.argv[i], str_argv[i].data(), str_argv[i].size());
m_userspace_info.argv[i][str_argv[i].size()] = '\0';
}
m_userspace_entry.argv[str_argv.size()] = nullptr;
m_userspace_info.argv[str_argv.size()] = nullptr;
m_userspace_info.envp = (char**)MUST(allocate(sizeof(char**) * (str_envp.size() + 1)));
for (size_t i = 0; i < str_envp.size(); i++)
{
m_userspace_info.envp[i] = (char*)MUST(allocate(str_envp[i].size() + 1));
memcpy(m_userspace_info.envp[i], str_envp[i].data(), str_envp[i].size());
m_userspace_info.envp[i][str_envp[i].size()] = '\0';
}
m_userspace_info.envp[str_envp.size()] = nullptr;
}
m_userspace_entry.argc = str_argv.size();
m_userspace_info.argc = str_argv.size();
// NOTE: These must be manually cleared since this function won't return after this point
str_argv.clear();

4
kernel/kernel/Thread.cpp
View File

@ -130,8 +130,8 @@ namespace Kernel
static entry_t entry_trampoline(
[](void*)
{
const auto& entry = Process::current().userspace_entry();
thread_userspace_trampoline(Thread::current().rsp(), entry.entry, entry.argc, entry.argv, entry.envp);
const auto& info = Process::current().userspace_info();
thread_userspace_trampoline(Thread::current().rsp(), info.entry, info.argc, info.argv, info.envp);
ASSERT_NOT_REACHED();
}
);

42
libc/unistd.cpp
View File

@ -206,9 +206,49 @@ int execl(const char* pathname, const char* arg0, ...)
return execv(pathname, argv);
}
int execle(const char* pathname, const char* arg0, ...)
{
va_list ap;
int argc = 0;
if (arg0)
{
va_start(ap, arg0);
argc = 1;
while (va_arg(ap, const char*))
argc++;
va_end(ap);
}
char** argv = (char**)malloc(sizeof(char*) * (argc + 1));
if (argv == nullptr)
{
errno = ENOMEM;
return -1;
}
char** envp = nullptr;
va_start(ap, arg0);
argv[0] = (char*)arg0;
for (int i = 1; i < argc; i++)
argv[i] = va_arg(ap, char*);
argv[argc] = nullptr;
envp = va_arg(ap, char**);
va_end(ap);
return execve(pathname, argv, envp);
}
int execv(const char* pathname, char* const argv[])
{
return syscall(SYS_EXEC, pathname, argv, nullptr);
return execve(pathname, argv, environ);
}
int execve(const char* pathname, char* const argv[], char* const envp[])
{
return syscall(SYS_EXEC, pathname, argv, envp);
}
pid_t fork(void)

9
userspace/Shell/main.cpp
View File

@ -43,13 +43,6 @@ int execute_command(BAN::StringView command)
}
else
{
struct stat stat_buf;
if (stat(args.front(), &stat_buf) == -1)
{
fprintf(stderr, "command not found: %s\n", args.front());
return 1;
}
pid_t pid = fork();
if (pid == 0)
{
@ -60,7 +53,7 @@ int execute_command(BAN::StringView command)
}
if (pid == -1)
{
perror("fork()");
perror("fork");
return 1;
}
int status;