Kernel: Expose command line and environment to /proc

kernel/include/kernel/FS/ProcFS/Inode.h

@@ -20,11 +20,11 @@ namespace Kernel
 		Process& m_process;
 	};
 
-	class ProcMemInode final : public RamInode
+	class ProcROInode final : public RamInode
 	{
 	public:
-		static BAN::ErrorOr<BAN::RefPtr<ProcMemInode>> create(Process&, RamFileSystem&, mode_t, uid_t, gid_t);
+		static BAN::ErrorOr<BAN::RefPtr<ProcROInode>> create(Process&, size_t (Process::*callback)(off_t, void*, size_t) const, RamFileSystem&, mode_t, uid_t, gid_t);
-		~ProcMemInode() = default;
+		~ProcROInode() = default;
 
 	protected:
 		virtual BAN::ErrorOr<size_t> read_impl(off_t, void*, size_t) override;
@@ -35,10 +35,11 @@ namespace Kernel
 		virtual bool has_data_impl() const override										{ return true; }
 
 	private:
-		ProcMemInode(Process&, RamFileSystem&, const FullInodeInfo&);
+		ProcROInode(Process&, size_t (Process::*)(off_t, void*, size_t) const, RamFileSystem&, const FullInodeInfo&);
 	
 	private:
 		Process& m_process;
+		size_t (Process::*m_callback)(off_t, void*, size_t) const;
 	};
 
 }

kernel/include/kernel/Process.h

@@ -139,7 +139,9 @@ namespace Kernel
 
 		PageTable& page_table() { return m_page_table ? *m_page_table : PageTable::kernel(); }
 
-		void get_meminfo(proc_meminfo_t*) const;
+		size_t proc_meminfo(off_t offset, void* buffer, size_t buffer_size) const;
+		size_t proc_cmdline(off_t offset, void* buffer, size_t buffer_size) const;
+		size_t proc_environ(off_t offset, void* buffer, size_t buffer_size) const;
 
 		bool is_userspace() const { return m_is_userspace; }
 		const userspace_info_t& userspace_info() const { return m_userspace_info; }
@@ -192,6 +194,9 @@ namespace Kernel
 		vaddr_t m_signal_handlers[_SIGMAX + 1] { };
 		uint64_t m_signal_pending_mask { 0 };
 
+		BAN::Vector<BAN::String> m_cmdline;
+		BAN::Vector<BAN::String> m_environ;
+
 		bool m_is_userspace { false };
 		userspace_info_t m_userspace_info;
 		ExitStatus m_exit_status;

kernel/kernel/FS/ProcFS/Inode.cpp

@@ -12,7 +12,9 @@ namespace Kernel
 			return BAN::Error::from_errno(ENOMEM);
 		auto inode = BAN::RefPtr<ProcPidInode>::adopt(inode_ptr);
 
-		TRY(inode->add_inode("meminfo"sv, MUST(ProcMemInode::create(process, fs, 0755, 0, 0))));
+		TRY(inode->add_inode("meminfo"sv, MUST(ProcROInode::create(process, &Process::proc_meminfo, fs, 0755, 0, 0))));
+		TRY(inode->add_inode("cmdline"sv, MUST(ProcROInode::create(process, &Process::proc_cmdline, fs, 0755, 0, 0))));
+		TRY(inode->add_inode("environ"sv, MUST(ProcROInode::create(process, &Process::proc_environ, fs, 0755, 0, 0))));
 
 		return inode;
 	}
@@ -23,36 +25,30 @@ namespace Kernel
 	{
 	}
 
-	BAN::ErrorOr<BAN::RefPtr<ProcMemInode>> ProcMemInode::create(Process& process, RamFileSystem& fs, mode_t mode, uid_t uid, gid_t gid)
+	BAN::ErrorOr<BAN::RefPtr<ProcROInode>> ProcROInode::create(Process& process, size_t (Process::*callback)(off_t, void*, size_t) const, RamFileSystem& fs, mode_t mode, uid_t uid, gid_t gid)
 	{
 		FullInodeInfo inode_info(fs, mode, uid, gid);
 
-		auto* inode_ptr = new ProcMemInode(process, fs, inode_info);
+		auto* inode_ptr = new ProcROInode(process, callback, fs, inode_info);
 		if (inode_ptr == nullptr)
 			return BAN::Error::from_errno(ENOMEM);
-		return BAN::RefPtr<ProcMemInode>::adopt(inode_ptr);
+		return BAN::RefPtr<ProcROInode>::adopt(inode_ptr);
 	}
 
-	ProcMemInode::ProcMemInode(Process& process, RamFileSystem& fs, const FullInodeInfo& inode_info)
+	ProcROInode::ProcROInode(Process& process, size_t (Process::*callback)(off_t, void*, size_t) const, RamFileSystem& fs, const FullInodeInfo& inode_info)
 		: RamInode(fs, inode_info)
 		, m_process(process)
+		, m_callback(callback)
 	{
 		m_inode_info.mode |= Inode::Mode::IFREG;
 	}
 
-	BAN::ErrorOr<size_t> ProcMemInode::read_impl(off_t offset, void* buffer, size_t buffer_size)
+	BAN::ErrorOr<size_t> ProcROInode::read_impl(off_t offset, void* buffer, size_t buffer_size)
 	{
 		ASSERT(offset >= 0);
 		if ((size_t)offset >= sizeof(proc_meminfo_t))
 			return 0;
-
+		return (m_process.*m_callback)(offset, buffer, buffer_size);
-		proc_meminfo_t meminfo;
-		m_process.get_meminfo(&meminfo);
-
-		size_t bytes = BAN::Math::min<size_t>(buffer_size, sizeof(meminfo) - offset);
-		memcpy(buffer, &meminfo, bytes);
-		
-		return bytes;
 	}
 
 }

kernel/kernel/Process.cpp

@@ -119,6 +119,9 @@ namespace Kernel
 		MUST(process->m_working_directory.push_back('/'));
 		process->m_page_table = BAN::UniqPtr<PageTable>::adopt(MUST(PageTable::create_userspace()));
 
+		TRY(process->m_cmdline.push_back({}));
+		TRY(process->m_cmdline.back().append(path));
+
 		process->m_loadable_elf = TRY(load_elf_for_exec(credentials, path, "/"sv, process->page_table()));
 		process->m_loadable_elf->reserve_address_space();
 
@@ -252,31 +255,77 @@ namespace Kernel
 			thread->set_terminating();
 	}
 
-	void Process::get_meminfo(proc_meminfo_t* out) const
+	size_t Process::proc_meminfo(off_t offset, void* buffer, size_t buffer_size) const
+	{
+		ASSERT(offset >= 0);
+		if ((size_t)offset >= sizeof(proc_meminfo_t))
+			return 0;
+
+		proc_meminfo_t meminfo;
+		meminfo.page_size = PAGE_SIZE;
+		meminfo.virt_pages = 0;
+		meminfo.phys_pages = 0;
+
 		{
 			LockGuard _(m_lock);
-
-		out->page_size = PAGE_SIZE;
-		out->virt_pages = 0;
-		out->phys_pages = 0;
-
 			for (auto* thread : m_threads)
 			{
-			out->virt_pages += thread->virtual_page_count();
+				meminfo.virt_pages += thread->virtual_page_count();
-			out->phys_pages += thread->physical_page_count();
+				meminfo.phys_pages += thread->physical_page_count();
 			}
 			for (auto& region : m_mapped_regions)
 			{
-			out->virt_pages += region->virtual_page_count();
+				meminfo.virt_pages += region->virtual_page_count();
-			out->phys_pages += region->physical_page_count();
+				meminfo.phys_pages += region->physical_page_count();
 			}
 			if (m_loadable_elf)
 			{
-			out->virt_pages += m_loadable_elf->virtual_page_count();
+				meminfo.virt_pages += m_loadable_elf->virtual_page_count();
-			out->phys_pages += m_loadable_elf->physical_page_count();
+				meminfo.phys_pages += m_loadable_elf->physical_page_count();
 			}
 		}
 
+		size_t bytes = BAN::Math::min<size_t>(sizeof(proc_meminfo_t) - offset, buffer_size);
+		memcpy(buffer, (uint8_t*)&meminfo + offset, bytes);
+		return bytes;
+	}
+
+	static size_t read_from_vec_of_str(const BAN::Vector<BAN::String>& container, size_t start, void* buffer, size_t buffer_size)
+	{
+		size_t offset = 0;
+		size_t written = 0;
+		for (const auto& elem : container)
+		{
+			if (start < offset + elem.size() + 1)
+			{
+				size_t elem_offset = 0;
+				if (offset < start)
+					elem_offset = start - offset;
+
+				size_t bytes = BAN::Math::min<size_t>(elem.size() + 1 - elem_offset, buffer_size - written);
+				memcpy((uint8_t*)buffer + written, elem.data() + elem_offset, bytes);
+
+				written += bytes;
+				if (written >= buffer_size)
+					break;
+			}
+			offset += elem.size() + 1;
+		}
+		return written;
+	}
+
+	size_t Process::proc_cmdline(off_t offset, void* buffer, size_t buffer_size) const
+	{
+		LockGuard _(m_lock);
+		return read_from_vec_of_str(m_cmdline, offset, buffer, buffer_size);
+	}
+
+	size_t Process::proc_environ(off_t offset, void* buffer, size_t buffer_size) const
+	{
+		LockGuard _(m_lock);
+		return read_from_vec_of_str(m_environ, offset, buffer, buffer_size);
+	}
+
 	BAN::ErrorOr<long> Process::sys_exit(int status)
 	{
 		exit(status, 0);
@@ -464,6 +513,9 @@ namespace Kernel
 			
 			m_userspace_info.argc = str_argv.size();
 
+			m_cmdline = BAN::move(str_argv);
+			m_environ = BAN::move(str_envp);
+
 			asm volatile("cli");
 		}