asmsh/src/shell_cmds.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"

const asmsh_cmd_t *asmsh_cmd_match(const char *text, int tlen)
{
	for(const asmsh_cmd_t *cmd=asmsh_CMDS; cmd->str; cmd++)
	{
		const int clen = strlen(cmd->str);
		if(cmd->sm && tlen >= cmd->sm && tlen < clen)
		{
			if(!strncmp(cmd->str, text, tlen))
			{
				return cmd;
			}
			continue;
		}
		else if(tlen != clen) { continue; }
		else
		{
			int cmp = strncmp(text, cmd->str, tlen);
			if(cmp < 0)
			{
				break;
			}
			else if(!cmp)
			{
				return cmd;
			}
		}
	}
	return NULL;
}


asmsh_cmd_args_t *asmsh_cmd_parse(const char *cmd)
{
	asmsh_cmd_args_t *ret;
	int cmdlen, err, argno;
	const char *ptr, *arg;

	if(!cmd || !*cmd) { return NULL; }
	if (*cmd != '.') { return NULL; }

	if(!(ret = malloc(sizeof(*ret))))
	{
		asmsh_log_fatal("Unable to allocate command");
		return NULL;
	}
	bzero(ret, sizeof(*ret));

	cmdlen=0;
	for(ptr=cmd; *ptr && *ptr != ' ' && *ptr != '\t' && *ptr != '\n'; ptr++)
	{
		cmdlen++;
	}
	if(cmdlen > ASMSH_CMD_MAXLEN)
	{
		asmsh_log_error("Invalid command"); //TODO printf command
		err=EINVAL;
		goto err;
	}
	strncpy(ret->cmd, cmd, cmdlen);
	ret->cmd[cmdlen] = '\0';
	// lstrip white chars
	for(; *ptr && (*ptr == ' ' || *ptr == '\t' || *ptr == '\n'); ptr++);
	if(!*ptr)
	{
		// end of command
		ret->args[0] = NULL;
		return ret;
	}
	arg = ptr;
	argno=0;
	do
	{
		int arglen = 0;
		for(; *ptr && *ptr != ' ' && *ptr != '\t' && *ptr != '\n'; ptr++)
		{
			arglen++;
		}
		ret->args[argno] = strndup(arg, arglen);
		if(!ret->args[argno])
		{
			asmsh_log_error("strndup args failed");
			err=errno;
			goto err;
		}
		argno++;
		if(argno >= ASMSH_CMD_MAXARG)
		{
			//too many arguments
			asmsh_log_error("too many arguments");
			err=EINVAL;
			goto err;
		}
		// lstrip white chars
		for(; *ptr && (*ptr == ' ' || *ptr == '\t' || *ptr == '\n'); ptr++);
		arg=ptr;
	}while(*ptr);

	ret->argc = argno;
	ret->args[argno] = NULL;
	return ret;
err:
	for(char **p=ret->args; *p; p++) { free(*p); }
	errno = err;
	free(ret);
	return NULL;
}


void asmsh_cmd_args_free(asmsh_cmd_args_t *args)
{
	if(!args) { return; }
	for(char **a=args->args; *a; a++)
	{
		free(*a);
	}
	free(args);
}


int asmsh_cmd_bcode_(asmsh_t *sh, char *argbuf, int bufsz, int argc, char **args)
{
	asmsh_bytecode_t bcode;
	char _buf[256], *buf;
	char code[256];
	const char *instr;
	int ret;

	if(!argbuf)
	{
		buf=_buf;
		bufsz=256;
	}
	else
	{
		buf=argbuf;
	}

	if(argc == 0)
	{
		if(sh->last_instr == NULL)
		{
			asmsh_log_error("No instruction compiled yet");
			return -1;
		}
		bcode = sh->last_bcode;
		instr = sh->last_instr;
	}
	else
	{
		char **arg;
		int sz = 0;
		for(arg=args;*arg;arg++)
		{
			sz+=snprintf(code+sz, 255-sz, "%s", *arg);
			if(*(arg+1))
			{
				code[sz] = ' ';
				sz++;
			}
		}
		code[sz]='\0';
		if(asmsh_asmc_compile(sh->cctx, code, &bcode) < 0)
		{
			return -1;
		}
		instr = code;
	}

	ret = snprintf(buf, bufsz, "%s = (%2d Bytes) ",
			instr, bcode.size);
	for(int i=0; i<sizeof(bcode.bytes); i++)
	{
		char repr[3] = "..";
		if(i<bcode.size)
		{
			snprintf(repr, 3, "%02x", bcode.bytes[i]);
		}
		repr[2]='\0';
		ret += snprintf(buf+ret, bufsz-ret, "%s%s%s",
				i&&(i%4==0)?" ":"",i==8?" ":"",
				repr);
	}
	buf[ret] = '\0';
	return 0;
}



int asmsh_cmd_quit(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	asmsh_cleanup(sh);
	return 1;
}


int asmsh_cmd_bcode(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	char str[256];
	int ret;

	ret = asmsh_cmd_bcode_(sh, str, 256, args->argc, args->args);
	if(ret)
	{
		return ret;
	}
	printf("%s\n", str);
	return 0;
}


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

	unsigned long addr;

	if(args->argc == 0)
	{
		if(sh->env->labels.syms_sz == 0)
		{
			printf("No label defined...\n");
			asmsh_log_info("Use '.label NAME [addr]' to define a label");
			return 0;
		}
		printf("%3ld labels :\n", sh->env->labels.syms_sz);
		for(size_t i=0; i<sh->env->labels.syms_sz; i++)
		{
			printf("\t%c%s\t %016lx\n",
					ASMSH_LABEL_SYM,
					sh->env->labels.syms[i].name,
					sh->env->labels.syms[i].addr);
		}
		return 0;
	}
	if(args->argc == 1)
	{
		addr = rip;
	}
	else
	{
		if(asmsh_cmd_parse_addr_expr(args, 1, rip, &addr) < 0)
		{
			asmsh_log_addr_expr_usage();
			return -1;
		}
	}

	int ret;
	const char *label = args->args[0];
	if(addr == 0)
	{
		ret = asmsh_symtable_del(&sh->env->labels, label);
		if(ret < 0)
		{
			asmsh_log_perror("Unable to delete label");
			return -1;
		}
		else if(ret > 0)
		{
			asmsh_log_warning("No label '%c%s'",
					ASMSH_LABEL_SYM, label);
			return -1;
		}
		asmsh_log_info("Label '%c%s' deleted", 
				ASMSH_LABEL_SYM, label);
		return 0;
	}
	ret = asmsh_symtable_add(&sh->env->labels, label, addr);
	if(ret < 0)
	{
		asmsh_log_perror("Unable to add label");
		return -1;
	}
	else if(ret > 0)
	{
		asmsh_log_warning("Label '%c%s' updated to %016x",
				ASMSH_LABEL_SYM, label, addr);
		return 0;
	}
	asmsh_log_info("Label '%c%s' %016lx added",
			ASMSH_LABEL_SYM, label, addr);
	return ret;
}


int asmsh_cmd_maps(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	if(asmsh_env_update_maps(sh->env) < 0)
	{
		perror("Unable to update maps info");
		return -1;
	}
	printf("%12s-%-12s perm %-8s %-6s %-10s %s\n", "start", "stop", "offset", "device",
			"inode", "path");
	for(int i=0; i<sh->env->mmap.size; i++)
	{
		const child_mmap_t *m = &sh->env->mmap.maps[i];
		printf("%012llx-%012llx %c%c%c  %08lx  %02lx:%02lx %10lu %s\n",
				(unsigned long long int)m->start,
				(unsigned long long int)m->stop,
				m->perm & PROT_READ ?'r':'-',
				m->perm & PROT_WRITE?'w':'-',
				m->perm & PROT_EXEC ?'x':'-',
				m->offset,
				(m->device & 0xFF00)>>8,
				m->device & 0xFF,
				m->inode,
				m->pathname);
	}
	return 0;
}

int asmsh_cmd_print_regs(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	asmsh_env_t *env = sh->env;
	asmsh_env_update_regs(env);
	struct user_regs_struct *r = &env->regs;
	
#define FLG(b, l) ( (r->eflags & (1<<b))?l:'-' )

	printf("rax: %016llx rbx: %016llx rcx: %016llx rdx: %016llx\n\
rbp: %016llx rsi: %016llx rdi: %016llx rsp: %016llx\n\
 r8: %016llx  r9: %016llx r10: %016llx r11: %016llx\n\
r12: %016llx r13: %016llx r14: %016llx r15: %016llx\n\
rip: %016llx flg: %016llx\n\
cs: %04llx ds: %04llx es: %04llx fs:%04llx gs: %04llx ss:%04llx\n\
flags: %c%c%c%c|%c%c%c\n\
       ODSZ|APC\n\
",	r->rax, r->rbx, r->rcx, r->rdx,\
	r->rbp, r->rsi, r->rdi, r->rsp,\
	r->r8, r->r9, r->r10, r->r11,\
	r->r12, r->r13, r->r14, r->r15,\
	r->rip, r->eflags,\
	r->cs, r->ds, r->es, r->fs, r->gs, r->ss,
	FLG(11,'O'), FLG(10, 'D'), FLG(7, 'S'), FLG(6, 'Z'),
	FLG(4, 'A'), FLG(2, 'P'), FLG(0, 'C'));

#undef FLG
	return 0;
}


int asmsh_cmd_step(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	int ret, status;
	ret = asmsh_env_step(sh->env, &status);

	if(ret > 1)
	{
		return status;
	}
	return ret;
}


int asmsh_cmd_syscalls(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	const int sz = sizeof(syscall_infos)/sizeof(*syscall_infos);
	int printed;
	char buf[512];

	printed = 0;
	for(int i=0; i<sz; i++)
	{
		int ret = snprintf(buf, 512, "%3d 0x%03x %20s ",
			syscall_infos[i].nr,
			syscall_infos[i].nr,
			syscall_infos[i].name);
		buf[ret] = '\0';
		printed += ret;
		if(printed > 80)
		{
			printf("\n");
			printed = ret;
		}
		printf("%s", buf);
	}
	printf("\n");
	return 0;
}


int asmsh_cmd_run(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	int ret, status;
	ret = asmsh_env_run(sh->env, &status);
	if(ret < 0)
	{
		perror("Unable to run as expected");
		asmsh_log_fatal("Error while child runs...");
		return -1;
	}
	else if(ret > 0)
	{
		return 1+WEXITSTATUS(status);
	}
	return 0;
}


int asmsh_cmd_reset(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	char *childpath = sh->child_path?strdup(sh->child_path):NULL;
	asmsh_cleanup(sh);
	int ret = asmsh_init(sh, childpath)<0?2:0;
	if(childpath) { free(childpath); }
	return ret;
}

// Display CPU flag resister values
int asmsh_cmd_flags(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	printf("Flags :\n");
#define printFLG(name, b) printf(" (%2d)%16s : %d\n", b, name,\
		(sh->env->regs.eflags & (1<<b))?1:0);
	printFLG("Overflow", 11);
	printFLG("Direction", 10);
	printFLG("Sign", 7);
	printFLG("Zero", 6);
	printFLG("Auxiliary carry", 4);
	printFLG("Parity", 2);
	printFLG("Carry", 0);
#undef printFLG
#define EFLG(b,n) ((sh->env->regs.eflags & (1<<b))?n:'-')
	printf("%c%c%c%c %c%c%c\n",
			EFLG(11,'O'), EFLG(10, 'D'), EFLG(7,'S'), EFLG(6,'Z'),
			EFLG(4,'A'), EFLG(2, 'P'), EFLG(0, 'C'));
	return 0;
}

// Print help (command list + help)
int asmsh_cmd_help_(asmsh_t *sh, asmsh_cmd_args_t *args)
{
	char buf[4096], abuf[64];
	int ret;

	ret = snprintf(buf, 4096, "Available commands :\n");
	for(const asmsh_cmd_t *cmd = asmsh_CMDS; cmd->str; cmd++)
	{
		snprintf(abuf, 64, "%s %s", cmd->sms, cmd->usage);
		ret += snprintf(buf+ret, 4096-ret, "  %-18s : %s\n", 
				abuf, cmd->desc);
	}
	dprintf(2, "%s", buf);
	return 0;
}