rizin/librz/parse/p/parse_x86_pseudo.c

// SPDX-FileCopyrightText: 2009-2020 nibble <nibble.ds@gmail.com>
// SPDX-FileCopyrightText: 2009-2020 pancake <pancake@nopcode.org>
// SPDX-License-Identifier: LGPL-3.0-only

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <rz_lib.h>
#include <rz_util.h>
#include <rz_analysis.h>
#include <rz_parse.h>
// 16 bit examples
//    0x0001f3a4      9a67620eca       call word 0xca0e:0x6267
//    0x0001f41c      eabe76de12       jmp word 0x12de:0x76be [2]
//    0x0001f56a      ea7ed73cd3       jmp word 0xd33c:0xd77e [6]
static int replace(int argc, char *argv[], char *newstr) {
#define MAXPSEUDOOPS 10
	int i, j, k, d;
	char ch;
	struct {
		char *op;
		char *str;
		int args[MAXPSEUDOOPS]; // XXX can't use flex arrays, all unused will be 0
	} ops[] = {
		{ "adc", "# += #", { 1, 2 } },
		{ "add", "# += #", { 1, 2 } },
		{ "and", "# &= #", { 1, 2 } },
		{ "call", "# ()", { 1 } },
		{ "cmove", "if (!var) # = #", { 1, 2 } },
		{ "cmovl", "if (var < 0) # = #", { 1, 2 } },
		{ "cmp", "var = # - #", { 1, 2 } },
		{ "cmpsq", "var = # - #", { 1, 2 } },
		{ "cmpsb", "while (CX != 0) { var = *(DS*16 + SI) - *(ES*16 + DI); SI++; DI++; CX--; if (!var) break; }", { 0 } },
		{ "cmpsw", "while (CX != 0) { var = *(DS*16 + SI) - *(ES*16 + DI); SI+=4; DI+=4; CX--; if (!var) break; }", { 0 } },
		{ "dec", "#--", { 1 } },
		{ "div", "# /= #", { 1, 2 } },
		{ "fabs", "abs(#)", { 1 } },
		{ "fadd", "# = # + #", { 1, 1, 2 } },
		{ "fcomp", "var = # - #", { 1, 2 } },
		{ "fcos", "# = cos(#)", { 1, 1 } },
		{ "fdiv", "# = # / #", { 1, 1, 2 } },
		{ "fiadd", "# = # / #", { 1, 1, 2 } },
		{ "ficom", "var = # - #", { 1, 2 } },
		{ "fidiv", "# = # / #", { 1, 1, 2 } },
		{ "fidiv", "# = # * #", { 1, 1, 2 } },
		{ "fisub", "# = # - #", { 1, 1, 2 } },
		{ "fnul", "# = # * #", { 1, 1, 2 } },
		{ "fnop", " ", { 0 } },
		{ "frndint", "# = (int) #", { 1, 1 } },
		{ "fsin", "# = sin(#)", { 1, 1 } },
		{ "fsqrt", "# = sqrt(#)", { 1, 1 } },
		{ "fsub", "# = # - #", { 1, 1, 2 } },
		{ "fxch", "#,# = #,#", { 1, 2, 2, 1 } },
		{ "idiv", "# /= #", { 1, 2 } },
		{ "imul", "# = # * #", { 1, 2, 3 } },
		{ "in", "# = io[#]", { 1, 2 } },
		{ "inc", "#++", { 1 } },
		{ "ja", "if (((unsigned) var) > 0) goto #", { 1 } },
		{ "jb", "if (((unsigned) var) < 0) goto #", { 1 } },
		{ "jbe", "if (((unsigned) var) <= 0) goto #", { 1 } },
		{ "je", "if (!var) goto #", { 1 } },
		{ "jg", "if (var > 0) goto #", { 1 } },
		{ "jge", "if (var >= 0) goto #", { 1 } },
		{ "jle", "if (var <= 0) goto #", { 1 } },
		{ "jmp", "goto #", { 1 } },
		{ "jne", "if (var) goto #", { 1 } },
		{ "lea", "# = #", { 1, 2 } },
		{ "mov", "# = #", { 1, 2 } },
		{ "movabs", "# = #", { 1, 2 } },
		{ "movq", "# = #", { 1, 2 } },
		{ "movaps", "# = #", { 1, 2 } },
		{ "movups", "# = #", { 1, 2 } },
		{ "movsd", "# = #", { 1, 2 } },
		{ "movsx", "# = #", { 1, 2 } },
		{ "movsxd", "# = #", { 1, 2 } },
		{ "movzx", "# = #", { 1, 2 } },
		{ "movntdq", "# = #", { 1, 2 } },
		{ "movnti", "# = #", { 1, 2 } },
		{ "movntpd", "# = #", { 1, 2 } },
		{ "pcmpeqb", "# == #", { 1, 2 } },

		{ "movdqu", "# = #", { 1, 2 } },
		{ "movdqa", "# = #", { 1, 2 } },
		{ "pextrb", "# = (byte) # [#]", { 1, 2, 3 } },
		{ "palignr", "# = # align #", { 1, 2, 3 } },
		{ "pxor", "# ^= #", { 1, 2 } },
		{ "xorps", "# ^= #", { 1, 2 } },
		{ "mul", "# = # * #", { 1, 2, 3 } },
		{ "mulss", "# = # * #", { 1, 2, 3 } },
		{ "neg", "# ~= #", { 1, 1 } },
		{ "nop", "", { 0 } },
		{ "not", "# = !#", { 1, 1 } },
		{ "or", "# |= #", { 1, 2 } },
		{ "out", "io[#] = #", { 1, 2 } },
		{ "pop", "pop #", { 1 } },
		{ "push", "push #", { 1 } },
		{ "ret", "return", { 0 } },
		{ "sal", "# <<= #", { 1, 2 } },
		{ "sar", "# >>= #", { 1, 2 } },
		{ "sete", "# = e", { 1 } },
		{ "setne", "# = ne", { 1 } },
		{ "shl", "# <<<= #", { 1, 2 } },
		{ "shld", "# <<<= #", { 1, 2 } },
		{ "sbb", "# = # - #", { 1, 1, 2 } },
		{ "shr", "# >>>= #", { 1, 2 } },
		{ "shlr", "# >>>= #", { 1, 2 } },
		//{ "strd",  "# = # - #", {1, 2, 3}},
		{ "sub", "# -= #", { 1, 2 } },
		{ "swap", "var = #; # = #; # = var", { 1, 1, 2, 2 } },
		{ "test", "var = # & #", { 1, 2 } },
		{ "xchg", "#,# = #,#", { 1, 2, 2, 1 } },
		{ "xadd", "#,# = #,#+#", { 1, 2, 2, 1, 2 } },
		{ "xor", "# ^= #", { 1, 2 } },
		{ NULL }
	};

	if (argc > 2 && !strcmp(argv[0], "xor")) {
		if (!strcmp(argv[1], argv[2])) {
			argv[0] = "mov";
			argv[2] = "0";
		}
	}
	for (i = 0; ops[i].op != NULL; i++) {
		if (!strcmp(ops[i].op, argv[0])) {
			if (newstr != NULL) {
				d = 0;
				j = 0;
				ch = ops[i].str[j];
				for (j = 0, k = 0; ch != '\0'; j++, k++) {
					ch = ops[i].str[j];
					if (ch == '#') {
						if (d >= MAXPSEUDOOPS) {
							// XXX Shouldn't ever happen...
							continue;
						}
						int idx = ops[i].args[d];
						d++;
						if (idx <= 0) {
							// XXX Shouldn't ever happen...
							continue;
						}
						const char *w = argv[idx];
						if (w != NULL) {
							strcpy(newstr + k, w);
							k += strlen(w) - 1;
						}
					} else {
						newstr[k] = ch;
					}
				}
				newstr[k] = '\0';
			}
			return true;
		}
	}

	/* TODO: this is slow */
	if (newstr) {
		newstr[0] = '\0';
		for (i = 0; i < argc; i++) {
			strcat(newstr, argv[i]);
			strcat(newstr, (i == 0 || i == argc - 1) ? " " : ",");
		}
	}
	return false;
}

static bool parse(RzParse *p, const char *data, RzStrBuf *sb) {
	char w0[256], w1[256], w2[256], w3[256];
	char str[1024] = { 0 };
	int i;
	size_t len = strlen(data);
	int sz = 32;
	char *buf, *ptr, *optr, *end;
	if (len >= sizeof(w0) || sz >= sizeof(w0)) {
		return false;
	}
	// strdup can be slow here :?
	if (!(buf = strdup(data))) {
		return false;
	}
	*w0 = *w1 = *w2 = *w3 = '\0';
	if (*buf) {
		end = buf + strlen(buf);
		ptr = strchr(buf, ' ');
		if (!ptr) {
			ptr = strchr(buf, '\t');
		}
		if (!ptr) {
			ptr = end;
		}
		*ptr = '\0';
		if (ptr != end) {
			for (++ptr; *ptr == ' '; ptr++) {
				;
			}
		}
		rz_str_ncpy(w0, buf, sizeof(w0));
		rz_str_ncpy(w1, ptr, sizeof(w1));
		optr = ptr;
		ptr = strchr(ptr, ',');
		if (ptr) {
			*ptr = '\0';
			for (++ptr; *ptr == ' '; ptr++) {
				;
			}
			rz_str_ncpy(w1, optr, sizeof(w1));
			rz_str_ncpy(w2, ptr, sizeof(w2));
			optr = ptr;
			ptr = strchr(ptr, ',');
			if (ptr) {
				*ptr = '\0';
				for (++ptr; *ptr == ' '; ptr++) {
					;
				}
				rz_str_ncpy(w2, optr, sizeof(w2));
				rz_str_ncpy(w3, ptr, sizeof(w3));
			}
		}
	}
	char *wa[] = { w0, w1, w2, w3 };
	int nw = 0;
	for (i = 0; i < 4; i++) {
		if (wa[i][0] != '\0') {
			nw++;
		}
	}
	/* TODO: interpretation of memory location fails*/
	// ensure imul & mul interpretations works
	if (strstr(w0, "mul")) {
		if (nw == 2) {
			rz_str_ncpy(wa[3], wa[1], sizeof(w3));

			switch (wa[3][0]) {
			case 'q':
			case 'r': // qword, r..
				rz_str_ncpy(wa[1], "rax", sizeof(w1));
				rz_str_ncpy(wa[2], "rax", sizeof(w2));
				break;
			case 'd':
			case 'e': // dword, e..
				if (strlen(wa[3]) > 2) {
					rz_str_ncpy(wa[1], "eax", sizeof(w1));
					rz_str_ncpy(wa[2], "eax", sizeof(w2));
				}
				break;
			default: // .x, .p, .i or word
				if (wa[3][1] == 'x' || wa[3][1] == 'p' ||
					wa[3][1] == 'i' || wa[3][0] == 'w') {
					rz_str_ncpy(wa[1], "ax", sizeof(w1));
					rz_str_ncpy(wa[2], "ax", sizeof(w2));
				} else { // byte and lowest 8 bit registers
					rz_str_ncpy(wa[1], "al", sizeof(w1));
					rz_str_ncpy(wa[2], "al", sizeof(w2));
				}
				break;
			}
		} else if (nw == 3) {
			rz_str_ncpy(wa[3], wa[2], sizeof(w3));
			rz_str_ncpy(wa[2], wa[1], sizeof(w2));
		}

		replace(nw, wa, str);

	} else if (strstr(w0, "lea")) {
		rz_str_replace_char(w2, '[', 0);
		rz_str_replace_char(w2, ']', 0);
		replace(nw, wa, str);
	} else if ((strstr(w1, "ax") || strstr(w1, "ah") || strstr(w1, "al")) && !p->retleave_asm) {
		if (!(p->retleave_asm = (char *)malloc(sz))) {
			return false;
		}
		rz_snprintf(p->retleave_asm, sz, "return %s", w2);
		replace(nw, wa, str);
	} else if ((strstr(w0, "leave") && p->retleave_asm) || (strstr(w0, "pop") && strstr(w1, "bp"))) {
		rz_str_ncpy(wa[0], " ", 2);
		rz_str_ncpy(wa[1], " ", 2);
		replace(nw, wa, str);
	} else if (strstr(w0, "ret") && p->retleave_asm) {
		rz_str_ncpy(str, p->retleave_asm, sz);
		RZ_FREE(p->retleave_asm);
	} else if (p->retleave_asm) {
		RZ_FREE(p->retleave_asm);
		replace(nw, wa, str);
	} else {
		replace(nw, wa, str);
	}
	free(buf);
	rz_strbuf_set(sb, str);
	return true;
}

static void parse_localvar(RzParse *p, char *newstr, size_t newstr_len, const char *var, const char *reg, char sign, const char *ireg, bool att) {
	RzStrBuf *sb = rz_strbuf_new("");
	if (att) {
		if (p->localvar_only) {
			if (ireg) {
				rz_strbuf_setf(sb, "(%%%s)", ireg);
			}
			snprintf(newstr, newstr_len - 1, "%s%s", var, rz_strbuf_get(sb));
		} else {
			if (ireg) {
				rz_strbuf_setf(sb, ", %%%s", ireg);
			}
			snprintf(newstr, newstr_len - 1, "%s(%%%s%s)", var, reg, rz_strbuf_get(sb));
		}
	} else {
		if (ireg) {
			rz_strbuf_setf(sb, " + %s", ireg);
		}
		if (p->localvar_only) {
			snprintf(newstr, newstr_len - 1, "%s%s", var, rz_strbuf_get(sb));
		} else {
			snprintf(newstr, newstr_len - 1, "%s%s %c %s", reg, rz_strbuf_get(sb), sign, var);
		}
	}
	rz_strbuf_free(sb);
}

static inline void mk_reg_str(const char *regname, int delta, bool sign, bool att, const char *ireg, char *dest, int len) {
	RzStrBuf *sb = rz_strbuf_new("");
	if (att) {
		if (ireg) {
			rz_strbuf_setf(sb, ", %%%s", ireg);
		}
		if (delta == 0) {
			snprintf(dest, len - 1, "(%%%s%s)", regname, rz_strbuf_get(sb));
		} else if (delta < 10) {
			snprintf(dest, len - 1, "%s%d(%%%s%s)", sign ? "" : "-", delta, regname, rz_strbuf_get(sb));
		} else {
			snprintf(dest, len - 1, "%s0x%x(%%%s%s)", sign ? "" : "-", delta, regname, rz_strbuf_get(sb));
		}
	} else {
		if (ireg) {
			rz_strbuf_setf(sb, " + %s", ireg);
		}
		if (delta == 0) {
			snprintf(dest, len - 1, "%s%s", regname, rz_strbuf_get(sb));
		} else if (delta < 10) {
			snprintf(dest, len - 1, "%s%s %c %d", regname, rz_strbuf_get(sb), sign ? '+' : '-', delta);
		} else {
			snprintf(dest, len - 1, "%s%s %c 0x%x", regname, rz_strbuf_get(sb), sign ? '+' : '-', delta);
		}
	}
	rz_strbuf_free(sb);
}

static bool subvar(RzParse *p, RzAnalysisFunction *f, RzAnalysisOp *op, char *data, char *str, int len) {
	const ut64 addr = op->addr;
	const int oplen = op->size;
	RzList *bpargs, *spargs;
	RzAnalysis *analysis = p->analb.analysis;
	RzListIter *bpargiter, *spiter;
	char oldstr[64], newstr[64];
	char *tstr = strdup(data);
	if (!tstr) {
		return false;
	}

	bool att = strchr(data, '%');

	if (p->subrel) {
		if (att) {
			char *rip = (char *)rz_str_casestr(tstr, "(%rip)");
			if (rip) {
				*rip = 0;
				char *pre = tstr;
				char *pos = rip + 6;
				char *word = rip;
				while (word > tstr && *word != ' ') {
					word--;
				}

				if (word > tstr) {
					*word++ = 0;
					*rip = 0;
					st64 n = rz_num_math(NULL, word);
					ut64 repl_num = oplen + addr + n;
					char *tstr_new = rz_str_newf("%s 0x%08" PFMT64x "%s", pre, repl_num, pos);
					*rip = '(';
					free(tstr);
					tstr = tstr_new;
				}
			}
		} else {
			char *rip = (char *)rz_str_casestr(tstr, "[rip");
			if (rip) {
				char *ripend = strchr(rip + 3, ']');
				const char *plus = strchr(rip, '+');
				const char *neg = strchr(rip, '-');
				char *tstr_new;
				ut64 repl_num = oplen + addr;

				if (!ripend) {
					ripend = "]";
				}
				if (plus) {
					repl_num += rz_num_get(NULL, plus + 1);
				}
				if (neg) {
					repl_num -= rz_num_get(NULL, neg + 1);
				}

				rip[1] = '\0';
				tstr_new = rz_str_newf("%s0x%08" PFMT64x "%s", tstr, repl_num, ripend);
				free(tstr);
				tstr = tstr_new;
			}
		}
	}

	if (!p->varlist) {
		free(tstr);
		return false;
	}
	bpargs = p->varlist(f, RZ_ANALYSIS_VAR_KIND_BPV);
	spargs = p->varlist(f, RZ_ANALYSIS_VAR_KIND_SPV);
	/* Iterate over stack pointer arguments/variables */
	bool ucase = *tstr >= 'A' && *tstr <= 'Z';
	if (ucase && tstr[1]) {
		ucase = tstr[1] >= 'A' && tstr[1] <= 'Z';
	}
	const char *ireg = op->ireg;
	RzAnalysisVarField *bparg, *sparg;
	rz_list_foreach (spargs, spiter, sparg) {
		char sign = '+';
		st64 delta = p->get_ptr_at
			? p->get_ptr_at(f, sparg->delta, addr)
			: ST64_MAX;
		if (delta == ST64_MAX && sparg->field) {
			delta = sparg->delta;
		} else if (delta == ST64_MAX) {
			continue;
		}
		if (delta < 0) {
			sign = '-';
			delta = -delta;
		}
		const char *reg = NULL;
		if (p->get_reg_at) {
			reg = p->get_reg_at(f, sparg->delta, addr);
		}
		if (!reg) {
			reg = analysis->reg->name[RZ_REG_NAME_SP];
		}
		mk_reg_str(reg, delta, sign == '+', att, ireg, oldstr, sizeof(oldstr));

		if (ucase) {
			rz_str_case(oldstr, true);
		}
		parse_localvar(p, newstr, sizeof(newstr), sparg->name, reg, sign, ireg, att);
		char *ptr = strstr(tstr, oldstr);
		if (ptr && (!att || *(ptr - 1) == ' ')) {
			if (delta == 0) {
				char *end = ptr + strlen(oldstr);
				if (*end != ']' && *end != '\0') {
					continue;
				}
			}
			tstr = rz_str_replace(tstr, oldstr, newstr, 1);
			break;
		} else {
			rz_str_case(oldstr, false);
			ptr = strstr(tstr, oldstr);
			if (ptr && (!att || *(ptr - 1) == ' ')) {
				tstr = rz_str_replace(tstr, oldstr, newstr, 1);
				break;
			}
		}
	}
	/* iterate over base pointer args/vars */
	rz_list_foreach (bpargs, bpargiter, bparg) {
		char sign = '+';
		st64 delta = p->get_ptr_at
			? p->get_ptr_at(f, bparg->delta, addr)
			: ST64_MAX;
		if (delta == ST64_MAX && bparg->field) {
			delta = bparg->delta + f->bp_off;
		} else if (delta == ST64_MAX) {
			continue;
		}
		if (delta < 0) {
			sign = '-';
			delta = -delta;
		}
		const char *reg = NULL;
		if (p->get_reg_at) {
			reg = p->get_reg_at(f, bparg->delta, addr);
		}
		if (!reg) {
			reg = analysis->reg->name[RZ_REG_NAME_BP];
		}
		mk_reg_str(reg, delta, sign == '+', att, ireg, oldstr, sizeof(oldstr));
		if (ucase) {
			rz_str_case(oldstr, true);
		}
		parse_localvar(p, newstr, sizeof(newstr), bparg->name, reg, sign, ireg, att);
		char *ptr = strstr(tstr, oldstr);
		if (ptr && (!att || *(ptr - 1) == ' ')) {
			if (delta == 0) {
				char *end = ptr + strlen(oldstr);
				if (*end != ']' && *end != '\0') {
					continue;
				}
			}
			tstr = rz_str_replace(tstr, oldstr, newstr, 1);
			break;
		} else {
			rz_str_case(oldstr, false);
			ptr = strstr(tstr, oldstr);
			if (ptr && (!att || *(ptr - 1) == ' ')) {
				tstr = rz_str_replace(tstr, oldstr, newstr, 1);
				break;
			}
		}
		// Figure out the first hex digit of the delta to know if we need a leading zero
		st64 delta_first_digit = delta;
		while (delta_first_digit >= 16) {
			delta_first_digit /= 16;
		}
		// Try with trailing-h notation (if using MASM syntax)
		snprintf(oldstr, sizeof(oldstr) - 1, "%s %c %s%xh", reg, sign, delta_first_digit > 9 ? "0" : "", (int)delta);
		if (rz_str_casestr(tstr, oldstr)) {
			tstr = rz_str_replace_icase(tstr, oldstr, newstr, 1, 0);
			break;
		}
		// Try with no spaces
		snprintf(oldstr, sizeof(oldstr) - 1, "[%s%c0x%x]", reg, sign, (int)delta);
		if (strstr(tstr, oldstr) != NULL) {
			tstr = rz_str_replace(tstr, oldstr, newstr, 1);
			break;
		}
	}

	char bp[32];
	if (analysis->reg->name[RZ_REG_NAME_BP]) {
		strncpy(bp, analysis->reg->name[RZ_REG_NAME_BP], sizeof(bp) - 1);
		if (isupper((ut8)*str)) {
			rz_str_case(bp, true);
		}
		bp[sizeof(bp) - 1] = 0;
	} else {
		bp[0] = 0;
	}

	bool ret = true;
	if (len > strlen(tstr)) {
		strcpy(str, tstr);
	} else {
		// TOO BIG STRING CANNOT REPLACE HERE
		ret = false;
	}
	free(tstr);
	rz_list_free(spargs);
	rz_list_free(bpargs);
	return ret;
}

RzParsePlugin rz_parse_plugin_x86_pseudo = {
	.name = "x86.pseudo",
	.desc = "X86 pseudo syntax",
	.parse = &parse,
	.subvar = &subvar,
};

#ifndef RZ_PLUGIN_INCORE
RZ_API RzLibStruct rizin_plugin = {
	.type = RZ_LIB_TYPE_PARSE,
	.data = &rz_parse_plugin_x86_pseudo,
	.version = RZ_VERSION
};
#endif