userspace: Rewrite everything

Everything.

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

Userspace/libc/interpreter/helper.c

@@ -0,0 +1,131 @@
+/*
+	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>
+#include <sys/types.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <errno.h>
+
+#include "elf.h"
+#include "misc.h"
+
+void *memset(void *s, int c, size_t n)
+{
+	uint8_t *p = s;
+	while (n--)
+		*p++ = c;
+	return s;
+}
+
+void *memcpy(void *dest, const void *src, size_t n)
+{
+	uint8_t *d = dest;
+	const uint8_t *s = src;
+	while (n--)
+		*d++ = *s++;
+	return dest;
+}
+
+size_t strlen(const char *s)
+{
+	const char *p = s;
+	while (*p)
+		p++;
+	return p - s;
+}
+
+char *strcpy(char *dest, const char *src)
+{
+	char *d = dest;
+	while ((*d++ = *src++))
+		;
+	return dest;
+}
+
+int strcmp(const char *l, const char *r)
+{
+	while (*l && *l == *r)
+	{
+		l++;
+		r++;
+	}
+	return *l - *r;
+}
+
+char *strcat(char *dest, const char *src)
+{
+	char *d = dest;
+	while (*d)
+		d++;
+	while ((*d++ = *src++))
+		;
+	return dest;
+}
+
+unsigned long elf_hash(const unsigned char *name)
+{
+	unsigned long hash = 0, high;
+	while (*name)
+	{
+		hash = (hash << 4) + *name++;
+		if ((high = hash & 0xF0000000))
+			hash ^= high >> 24;
+		hash &= ~high;
+	}
+	return hash;
+}
+
+uint32_t gnu_hash(const char *name)
+{
+	uint32_t hash = 5381;
+	for (; *name; name++)
+	{
+		hash = (hash << 5) + hash + (unsigned char)(*name); // hash * 33 + c
+	}
+	return hash;
+}
+
+Elf64_Sym *find_symbol(const char *name, uint32_t *hash_table, Elf64_Sym *symtab, const char *strtab)
+{
+	/* Symbol Hash Table
+	|-------------------|
+	|      nbucket      |
+	|-------------------|
+	|      nchain       |
+	|-------------------|
+	|     bucket[0]     |
+	|      . . .        |
+	|bucket[nbucket - 1]|
+	|-------------------|
+	|     chain[0]      |
+	|      . . .        |
+	| chain[nchain - 1] |
+	|-------------------|
+	*/
+	unsigned long h = elf_hash(name);		  // or gnu_hash(name)
+	unsigned long bucket = h % hash_table[0]; // hash_table[0] = nbucket
+
+	for (unsigned long i = hash_table[2 + bucket];
+		 i != STN_UNDEF;
+		 i = hash_table[2 + hash_table[0] + i])
+	{
+		if (!strcmp(&strtab[symtab[i].st_name], name))
+			return &symtab[i];
+	}
+	return NULL;
+}