asmsh/src/shell_cmd_breakpoint.c

/* Copyright Yann Weber <asmsh@yannweb.net>
   This file is part of asmsh.

   asmsh 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 any later version.
   
   asmsh 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 asmsh. If not, see <https://www.gnu.org/licenses/>.
*/
#include "shell_cmds.h"

/** Add a breakpoint
 * @param asmsh_t* The shell
 * @param asmsh_cmd_args_t* The command arguments
 * @param int The first argument of the expression
 * @return -1 on error else 0
 */
static int brk_add(asmsh_t *sh, asmsh_cmd_args_t *args, int expr_first);

/** Remove a breakpoint
 * @param asmsh_t* The shell
 * @param asmsh_cmd_args_t* The command arguments
 * @param int The first argument of the expression
 * @return -1 on error else 0
 */
static int brk_del(asmsh_t *sh, asmsh_cmd_args_t *args, int expr_first);

/** Add a breakpoint after an instruction
 * @param asmsh_t* The shell
 * @param asmsh_cmd_args_t* The command arguments
 * @param int The first argument of the expression
 * @return -1 on error else 0
 */
static int brk_after(asmsh_t *sh, asmsh_cmd_args_t *args, int first);

/** List all breakpoints
 * @param asmsh_t* The shell
 * @param asmsh_cmd_args_t* The command arguments
 * @param int The first argument of the expression
 * @return -1 on error else 0
 * @todo add filters arguments
 */
static int brk_ls(asmsh_t *sh, asmsh_cmd_args_t *args, int expr_first);

/** Add a breakpoint and display a message about it
 * @param asmsh_t The shell
 * @param unsigned long The breakpoint address
 * @returns 0 if no error or if allready exist else -1
 */
static int brk_add_or_err(asmsh_t *sh, unsigned long addr);


void log_brk_usage()
{
	asmsh_log_info("Available commands are :");
	asmsh_log_info("\tadd [addr_expr]");
	asmsh_log_info("\t\tAdd a new breakpoint (optionnal/implicit)");
	asmsh_log_info("\tdel|d addr_expr");
	asmsh_log_info("\t\tDelete a breakpoint");
	asmsh_log_info("\tafter|a INSTRUCTION");
	asmsh_log_info("\t\tAdd a new breakpoint after an instruction");
	asmsh_log_info("\tlist|ls|l");
	asmsh_log_info("\t\tList existing breakpoints");
	asmsh_log_addr_expr_usage();
}


int asmsh_cmd_breakpoint(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	int ret;

	if(args->argc == 0 || args->args[0][0] == '.' || \
			(args->args[0][0] >= '0' && args->args[0][0] <= '9'))
	{
		if((ret = brk_add(sh, args, 0)) < 0)
		{
			asmsh_log_addr_expr_usage();
		}
		return ret;
	}
	// At least 1 arg, 1st arg chr is not in [0-9] nor is '.'
	// Looking for specific commands argument
	if(strcmp(args->args[0], "a") == 0 || \
			strcmp(args->args[0], "after") == 0)
	{
		return brk_after(sh, args, 1);
	}
	else if(strcmp(args->args[0], "add") == 0)
	{
		if((ret = brk_add(sh, args, 1)) < 0)
		{
			asmsh_log_addr_expr_usage();
		}
		return ret;
	}
	else if(strcmp(args->args[0], "d") == 0 || \
			strcmp(args->args[0], "del") == 0 || \
			strcmp(args->args[0], "rm") == 0)
	{
		ret = brk_del(sh, args, 1);
		return ret;
	}
	else if(strcmp(args->args[0], "list") == 0 || \
			strcmp(args->args[0], "ls") == 0 || \
			strcmp(args->args[0], "l") == 0)
	{
		ret = brk_ls(sh, args, 1);
		return ret;
	}
	else
	{
		asmsh_log_error("Unrecognized action '%s'", args->args[0]);
		log_brk_usage();
	}
	return -1;
}

static int brk_after(asmsh_t *sh, asmsh_cmd_args_t *args, int first)
{
	asmsh_bytecode_t bcode;
	size_t sz;
	sz = 0;
	for(int i=1; i<args->argc; i++)
	{
		sz += strlen(args->args[i]) + 1;
	}
	char instr[sz];
	char *iptr = instr;
	for(int i=1; i<args->argc; i++)
	{
		iptr += sprintf(iptr, "%s ", args->args[i]);
	}
	instr[sz-1] = '\0';

	if(asmsh_asmc_compile(sh->cctx, instr, &bcode) < 0 ||\
			asmsh_env_write_code(sh->env, &bcode) < 0)
	{
		asmsh_log_perror("Unable to add breakpoint");
		return -1;
	}
	if(brk_add_or_err(sh, sh->env->regs.rip + bcode.size) < 0)
	{
		return -1;
	}

	int status;
	int ret = asmsh_env_step(sh->env, &status);

	return ret;
}

static int brk_add(asmsh_t *sh, asmsh_cmd_args_t *args, int expr_first)
{
	const unsigned long rip = sh->env->regs.rip;

	unsigned long addr;

	if(asmsh_cmd_parse_addr_expr(args, expr_first, rip, &addr) < 0)
	{
		return -1;
	}
	return brk_add_or_err(sh, addr);
}

static int brk_add_or_err(asmsh_t *sh, unsigned long addr)
{
	int ret = asmsh_brk_add(&sh->env->brks, addr);
	if(ret < 0)
	{
		int err = errno;
		asmsh_log_error("Unable to set breakpoint @ %016lX : %s",
				addr, strerror(errno));
		errno = err;
		return -1;
	}
	else if(ret > 0)
	{
		asmsh_log_warning("Breakpoint @ %016lX allready set", addr);
		return 0;
	}
	asmsh_log_info("Set breakpoint @ %016lX", addr);
	return 0;
}

static int brk_del(asmsh_t *sh, asmsh_cmd_args_t *args, int expr_first)
{
	const unsigned long rip = sh->env->regs.rip;

	unsigned long addr;

	if(asmsh_cmd_parse_addr_expr(args, expr_first, rip, &addr) < 0)
	{
		return -1;
	}

	int ret = asmsh_brk_del(&sh->env->brks, addr);
	if(ret < 0)
	{
		int err = errno;
		asmsh_log_error("Unable to remove breakpoint @ %016lX : %s",
				addr, strerror(errno));
		errno = err;
		return -1;
	}
	else if(ret > 0)
	{
		asmsh_log_warning("Breakpoint @ %016lX do not exists", addr);
		return -1;
	}
	asmsh_log_info("Removed breakpoint @ %016lX", addr);
	return 0;
}


static int brk_ls(asmsh_t *sh, asmsh_cmd_args_t *args, int expr_first)
{
	for(size_t i=0; i<sh->env->brks.sz; i++)
	{
		printf("0x%016lx\n", sh->env->brks.addrs[i]);
	}
	printf("%ld breakpoints\n", sh->env->brks.sz);
	return 0;
}