Implements a .breakpoint command

Makefile.am

@@ -1,8 +1,9 @@
 bin_PROGRAMS = asmsh child
 
 libcheck_asmsh_a_SOURCES = mmap_parse.c asm_env.c breakpoints.c compile.c logger.c \
-			   completion.c shell.c shell_cmds.c shell_sym.c \
-			   history.c
+			   completion.c history.c \
+			   shell.c shell_cmds.c shell_sym.c \
+			   shell_cmd_breakpoint.c
 
 asmsh_SOURCES = asmsh.c $(libcheck_asmsh_a_SOURCES)
 child_SOURCES = child.s

asm_env.c

@@ -39,6 +39,8 @@ asmsh_env_t* asmsh_env(const char *childpath)
 	}
 	child_mmap_init(&(res->mmap));
 
+	asmsh_brk_init(&res->brks);
+
 	res->childpath = NULL;
 	if(childpath && (res->childpath = strdup(childpath)) == NULL)
 	{
@@ -86,6 +88,7 @@ void asmsh_env_free(asmsh_env_t *asmenv)
 		free(asmenv->mmap.maps);
 	}
 	kill(asmenv->pid, SIGKILL);
+	asmsh_brk_free(&asmenv->brks);
 	free(asmenv->childpath);
 	free(asmenv);
 }

asm_env.h

@@ -27,6 +27,7 @@
 
 #include "mmap_parse.h"
 #include "compile.h"
+#include "breakpoints.h"
 
 ///! Initial size of the child's memory map with PROT_EXEC permission
 #define ASMSH_CHILD_TEXT_MAP_SZ 0x1000 // defined in child.s
@@ -56,6 +57,10 @@ struct asmsh_env_s
 	/** Pointer on current write addr in child's map */
 	unsigned char *txt_map_ptr;
 
+	/** List of breakpoints addresses in child's memory */
+	asmsh_brk_t brks;
+
+	/** @todo check & delete useless properties */
 	/** Pointer on the next addr where we should write some
 	 *  compiled bytecode */
 	unsigned char *code_write_ptr;

asmsh.h

@@ -8,7 +8,7 @@ A shell designed to run assembly (for the moment only x86_64 is supported).
 A simple programm is spawned by the shell, and each instructions are runned in the
 subprocess environment.
 
-@section UI
+@section man_ui USER INTERFACE
 
 For the moment, the UI is implemented using GNU readline with basic support for
 completion (using tab).
@@ -16,6 +16,9 @@ completion (using tab).
 The prompt is composed like "asmsh@RIPVAL > " where RIPVAL is the RIP register (
 Instruction Pointer ) value in hexadecimal.
 
+Other readline(3) features are available like up arrow to display previous commands,
+C^R for history search, etc.
+
 @section INSTRUCTIONS
 
 The shell uses the GNU as compiler from binutils, the instructions syntax
@@ -109,12 +112,13 @@ asmsh@0x7f6e312e5022 >
 @section TODO TODOLIST
 
 @todo Implement breakpoints
+@todo Implement command for memory read/dump
 @todo Implement symbols for jumps
+@todo Add support for label declarations & references
 @todo Implement write without exec
 @todo Implement function declaration
-@todo Implement command for memory read/dump
 @todo Add switch between intel's & AT&T's syntaxes.
-@todo Add support for label declarations & references
+@todo Rationalise commands argument parsing
 
 @section AUTHOR
 Written by Yann Weber <yann.weber@members.fsf.org>

shell_cmd_breakpoint.c

@@ -0,0 +1,279 @@
+/* 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);
+
+/** 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);
+
+/** Parse a breakpoint address expression
+ *
+ * An expression must be of the form A [OP B] with A and B
+ * an integer or '.' for current RIP value and OP one of + or -
+ *
+ * @param asmsh_cmd_args_t* The breakpoint command argument list
+ * @param int The first argument of the address expression
+ * @param const unsigned long RIP value
+ * @param unsigned long* A pointer on the result address
+ *
+ * @returns -1 on error and 0 if ok
+ */
+static int parse_addr_expr(asmsh_cmd_args_t *args, int first,
+		const unsigned long rip,  unsigned long *addr);
+
+/** Utility function for @ref parse_addr_expr() that parse an expression value.
+ *
+ * An expression can be . for rip value or an unsigned long, possibly in hex, etc
+ * @param const char* The value
+ * @param unsigned long The value of RIP
+ * @param unsigned long* A pointer on the result
+ * @return -1 on error else 0
+ */
+static int addr_expr_val(const char *val, unsigned long rip, unsigned long *res);
+
+
+void log_brk_usage()
+{
+	asmsh_log_info("Available commands are : add, a, del, d, rm, list, ls, l");
+}
+
+void log_expr_usage()
+{
+	asmsh_log_info("Bad argument, expected an expression of the form A + B or A - B with A and B an integer or '.' (for current RIP value)");
+}
+
+
+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)
+		{
+			log_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], "add") == 0)
+	{
+		if((ret = brk_add(sh, args, 1)) < 0)
+		{
+			log_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_add(asmsh_t *sh, asmsh_cmd_args_t *args, int expr_first)
+{
+	const unsigned long rip = sh->env->regs.rip;
+
+	unsigned long addr;
+
+	if(parse_addr_expr(args, expr_first, rip, &addr) < 0)
+	{
+		return -1;
+	}
+
+	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 -1;
+	}
+	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(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;
+}
+
+static int addr_expr_val(const char *val, unsigned long rip, unsigned long *res)
+{
+	if(strcmp(".", val) == 0)
+	{
+		*res = rip;
+		return 0;
+	}
+
+	char *endptr;
+	errno = 0;
+	*res = strtoul(val, &endptr, 0);
+	if(errno != 0)
+	{
+		return -1;
+	}
+	else if(*endptr != '\0')
+	{
+		errno = EINVAL;
+		return -1;
+	}
+	return 0;
+}
+
+static int parse_addr_expr(asmsh_cmd_args_t *args, int first,
+		const unsigned long rip, unsigned long *addr)
+{
+	char * const * argv = args->args + first;
+	const int argc = args->argc - first;
+
+	unsigned long val[2];
+
+	switch(argc)
+	{
+		case 0:
+			*addr = rip;
+			break;
+		case 1:
+			if(addr_expr_val(argv[0], rip, addr) < 0)
+			{
+				int err = errno;
+				asmsh_log_error("Invalid expression value '%s': %s",
+						argv[0], strerror(errno));
+				errno = err;
+				return -1;
+			}
+			break;
+		case 3:
+
+			for(int i=0; i<2; i++)
+			{
+				const char *arg = i ? argv[2]:argv[0];
+				if(addr_expr_val(arg, rip, &val[i]) < 0)
+				{
+
+					asmsh_log_error("Invalid value '%s' in expression '%s %s %s' : %s",
+							arg,
+							argv[0], argv[1], argv[2],
+							strerror(errno));
+					return -1;
+				}
+			}
+
+			const char operator = strlen(argv[1]) == 1 ? argv[1][0]: '\0';
+			switch(operator)
+			{
+				case '+':
+					*addr = val[0] + val[1];
+					break;
+				case '-':
+					*addr = val[0] - val[1];
+					break;
+				default:
+					asmsh_log_error("Invalid operator '%s' in expression '%s %s %s'",
+							argv[1],
+							argv[0], argv[1], argv[2]);
+					return -1;
+			}
+			break;
+		default:
+			//USAGE !
+			asmsh_log_error("Unexexpected argument count for an expression. Expecting one of 0, 1 or 3 but got %d", argc);
+			return -1;
+	}
+	return 0;
+}

shell_cmds.h

@@ -91,6 +91,9 @@ const char *asmsh_cmd_help(asmsh_t *sh);
 // Quit the shell
 int asmsh_cmd_quit(asmsh_t *sh, asmsh_cmd_args_t *args);
 
+// Defined in @file shell_cmd_breakpoint.c
+int asmsh_cmd_breakpoint(asmsh_t *sh, asmsh_cmd_args_t *args);
+
 // Print an instruction bytecode 
 int asmsh_cmd_bcode_(asmsh_t *sh, char *buf, int bufsz, int argc, char **args);
 int asmsh_cmd_bcode(asmsh_t *sh, asmsh_cmd_args_t *args);
@@ -116,6 +119,9 @@ int asmsh_cmd_help_(asmsh_t *sh, asmsh_cmd_args_t *args);
  * The list of shell commands
  */
 static const asmsh_cmd_t asmsh_CMDS[] = {
+	{".breakpoint", asmsh_cmd_breakpoint, 3,
+	 ".br(eakpoint)", "[addr]",
+	 "Set a breakpoint"},
 	{".bytecode", asmsh_cmd_bcode, 2,
 	 ".b(ytecode)", "",
 	 "display last instruction bytecode"},