userspace: Rewrite everything

Everything.

Signed-off-by: EnderIce2 <enderice2@protonmail.com>

Userspace/libc/interpreter/start.c

@@ -0,0 +1,139 @@
+/*
+	This file is part of Fennix C Library.
+
+	Fennix C Library is free software: you can redistribute it and/or
+	modify it under the terms of the GNU General Public License as
+	published by the Free Software Foundation, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix C Library is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix C Library. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <fennix/syscalls.h>
+
+// const char __interp[] __attribute__((section(".interp"))) = "/boot/fennix.elf";
+
+#ifndef LIBC_GIT_COMMIT
+#define LIBC_GIT_COMMIT "0000000000000000000000000000000000000000"
+#endif
+
+#define HEX_DIGIT(c) (((c) >= '0' && (c) <= '9') ? ((c) - '0') : ((c) - 'a' + 10))
+#define CONVERT_TO_BYTE(h, l) ((HEX_DIGIT(h) << 4) | HEX_DIGIT(l))
+#define HASH_BYTES(hex)                 \
+	{CONVERT_TO_BYTE(hex[0], hex[1]),   \
+	 CONVERT_TO_BYTE(hex[2], hex[3]),   \
+	 CONVERT_TO_BYTE(hex[4], hex[5]),   \
+	 CONVERT_TO_BYTE(hex[6], hex[7]),   \
+	 CONVERT_TO_BYTE(hex[8], hex[9]),   \
+	 CONVERT_TO_BYTE(hex[10], hex[11]), \
+	 CONVERT_TO_BYTE(hex[12], hex[13]), \
+	 CONVERT_TO_BYTE(hex[14], hex[15]), \
+	 CONVERT_TO_BYTE(hex[16], hex[17]), \
+	 CONVERT_TO_BYTE(hex[18], hex[19]), \
+	 CONVERT_TO_BYTE(hex[20], hex[21]), \
+	 CONVERT_TO_BYTE(hex[22], hex[23]), \
+	 CONVERT_TO_BYTE(hex[24], hex[25]), \
+	 CONVERT_TO_BYTE(hex[26], hex[27]), \
+	 CONVERT_TO_BYTE(hex[28], hex[29]), \
+	 CONVERT_TO_BYTE(hex[30], hex[31]), \
+	 CONVERT_TO_BYTE(hex[32], hex[33]), \
+	 CONVERT_TO_BYTE(hex[34], hex[35]), \
+	 CONVERT_TO_BYTE(hex[36], hex[37]), \
+	 CONVERT_TO_BYTE(hex[38], hex[39])}
+
+/* These are declared in GNU ld */
+enum
+{
+	NT_FNX_ABI_TAG = 1,
+	NT_FNX_VERSION = 2,
+	NT_FNX_BUILD_ID = 3,
+	NT_FNX_ARCH = 4
+};
+
+typedef struct Elf_Nhdr
+{
+	__UINT32_TYPE__ n_namesz;
+	__UINT32_TYPE__ n_descsz;
+	__UINT32_TYPE__ n_type;
+	char n_name[];
+} __attribute__((packed)) Elf_Nhdr;
+
+const struct
+{
+	Elf_Nhdr header;
+	char name[4];
+	__UINT32_TYPE__ desc[4];
+} __abi_tag __attribute__((aligned(4), section(".note.ABI-tag"))) = {
+	.header = {
+		.n_namesz = 4,							 /* "FNX" + '\0' */
+		.n_descsz = sizeof(__UINT32_TYPE__) * 4, /* Description Size */
+		.n_type = NT_FNX_ABI_TAG,				 /* Type */
+	},
+	.name = "FNX",
+	.desc = {0, 0, 0, 0},
+};
+
+const struct
+{
+	Elf_Nhdr header;
+	char name[4];
+	__UINT8_TYPE__ desc[20];
+} __build_id __attribute__((aligned(4), section(".note.build-id"))) = {
+	.header = {
+		.n_namesz = 4,							 /* "FNX" + '\0' */
+		.n_descsz = sizeof(__UINT8_TYPE__) * 20, /* Description Size */
+		.n_type = NT_FNX_BUILD_ID,				 /* Type */
+	},
+	.name = "FNX",
+	.desc = HASH_BYTES(LIBC_GIT_COMMIT),
+};
+
+void __init_print_buffer();
+void __fini_print_buffer();
+
+__attribute__((naked, used, no_stack_protector)) void _start()
+{
+	__asm__(
+		"xorq %rbp, %rbp\n" /* Clear rbp */
+
+		"push %rdi\n"
+		"push %rsi\n"
+		"push %rdx\n"
+		"push %rcx\n"
+		"push %r8\n"
+		"push %r9\n"
+
+		"call __init_print_buffer\n" /* Call __init_print_buffer */
+		"call _dl_preload\n"		 /* Call _dl_preload */
+		"movl %eax, %edi\n"			 /* Move return value to edi */
+		"cmp $0, %edi\n"			 /* Check if return value is 0 */
+		"jne _exit\n"				 /* If not, jump to _exit */
+
+		"pop %r9\n"
+		"pop %r8\n"
+		"pop %rcx\n"
+		"pop %rdx\n"
+		"pop %rsi\n"
+		"pop %rdi\n"
+
+		"call main\n"		/* Call _dl_main */
+		"movl %eax, %edi\n" /* Move return value to edi */
+		"call _exit\n");	/* Call _exit */
+}
+
+__attribute__((no_stack_protector)) _Noreturn void _exit(int status)
+{
+	__fini_print_buffer();
+	call_exit(status);
+	/* At this point, the program *SHOULD* have exited. */
+	__asm__("ud2\n");
+	__builtin_unreachable();
+}
+
+__attribute__((no_stack_protector)) _Noreturn void _Exit(int status) { _exit(status); }