[U-Boot-Users] [patch #10/11] HUSH parser fixes.

30 Mar 2004

Hello
The following patch fixes various shortcomings in the
hush parser.
1. A new test command was added. This is a simplified
   version of the one in the sh shell.
2. A new exit command was added which terminates the
   current executing script.
3. Handing of $? (exit code of last executed command), was
   wrong. Instead of being evaluated in the proper place
   it was evaluated once at the start of the evaluation.
For example the following script worked like this.
test 1 -eq 2   # set $? to 1
   echo $?        # outputs 1
   test 1 -eq 1   # set $? to 0
   echo $?        # still outputs 1
Now it is fixed.
4. The simplified parser uses '(' and ')' for enclosing variables.
   This caused problems when migrating to hush because hash uses
   '{' and '}'. Modified to accept parentheses too.
Regards
Pantelis
README           |    5 +
 common/command.c |  153 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 common/hush.c    |   93 ++++++++++++++++++++++++++++++---
 3 files changed, 242 insertions(+), 9 deletions(-)
diff -ruNb u-boot-original/README u-boot-parser/README

--- u-boot-original/README	2004-03-30 14:37:28.395972064 +0300
+++ u-boot-parser/README	2004-03-30 15:54:35.451552696 +0300
@@ -1270,6 +1270,11 @@
    	of the backslashes before semicolons and special
    	symbols.
+	Note 2:
+		In order to allow compatibility between the original
+		parser we also allow to enclose variables with '('
+		and ')'. Example $ipaddr = ${ipaddr} = $(ipaddr).
+
 - Default Environment:
    	CONFIG_EXTRA_ENV_SETTINGS
diff -ruNb u-boot-original/common/command.c u-boot-parser/common/command.c
--- u-boot-original/common/command.c	2004-03-30 14:37:28.665931024 +0300
+++ u-boot-parser/common/command.c	2004-03-30 15:37:59.834909432 +0300
@@ -74,6 +74,159 @@
    "    - echo args to console; \c suppresses newline\n"
 );
+#ifdef CFG_HUSH_PARSER
+
+int
+do_test (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+	char **ap;
+	int left, adv, expr, last_expr, neg, last_cmp;
+
+	/* args? */
+	if (argc < 3)
+		return 1;
+
+#if 0
+	{
+		printf("test:");
+		left = 1; 
+		while (argv[left])
+			printf(" %s", argv[left++]);
+	}
+#endif
+	
+	last_expr = 0;
+	left = argc - 1; ap = argv + 1;
+	if (left > 0 && strcmp(ap[0], "!") == 0) {
+		neg = 1;
+		ap++;
+		left--;
+	} else
+		neg = 0;
+
+	expr = -1;
+	last_cmp = -1;
+	last_expr = -1;
+	while (left > 0) {
+
+		if (strcmp(ap[0], "-o") == 0 || strcmp(ap[0], "-a") == 0)
+			adv = 1;
+		else if (strcmp(ap[0], "-z") == 0 || strcmp(ap[0], "-n") == 0)
+			adv = 2;
+		else
+			adv = 3;
+
+		if (left < adv) {
+			expr = 1;
+			break;
+		}
+
+		if (adv == 1) {
+			if (strcmp(ap[0], "-o") == 0) {
+				last_expr = expr;
+				last_cmp = 0;
+			} else if (strcmp(ap[0], "-a") == 0) {
+				last_expr = expr;
+				last_cmp = 1;
+			} else {
+				expr = 1;
+				break;
+			}
+		}
+
+		if (adv == 2) {
+			if (strcmp(ap[0], "-z") == 0)
+				expr = strlen(ap[1]) == 0 ? 0 : 1;
+			else if (strcmp(ap[0], "-n") == 0)
+				expr = strlen(ap[1]) == 0 ? 1 : 0;
+			else {
+				expr = 1;
+				break;
+			}
+
+			if (last_cmp == 0)
+				expr = last_expr || expr;
+			else if (last_cmp == 1)
+				expr = last_expr && expr;
+			last_cmp = -1;
+		}
+
+		if (adv == 3) {
+			if (strcmp(ap[1], "=") == 0)
+				expr = strcmp(ap[0], ap[2]) == 0;
+			else if (strcmp(ap[1], "!=") == 0)
+				expr = strcmp(ap[0], ap[2]) != 0;
+			else if (strcmp(ap[1], ">") == 0)
+				expr = strcmp(ap[0], ap[2]) > 0;
+			else if (strcmp(ap[1], "<") == 0)
+				expr = strcmp(ap[0], ap[2]) < 0;
+			else if (strcmp(ap[1], "-eq") == 0)
+				expr = simple_strtol(ap[0], NULL, 10) == simple_strtol(ap[2], NULL, 10);
+			else if (strcmp(ap[1], "-ne") == 0)
+				expr = simple_strtol(ap[0], NULL, 10) != simple_strtol(ap[2], NULL, 10);
+			else if (strcmp(ap[1], "-lt") == 0)
+				expr = simple_strtol(ap[0], NULL, 10) < simple_strtol(ap[2], NULL, 10);
+			else if (strcmp(ap[1], "-le") == 0)
+				expr = simple_strtol(ap[0], NULL, 10) <= simple_strtol(ap[2], NULL, 10);
+			else if (strcmp(ap[1], "-gt") == 0)
+				expr = simple_strtol(ap[0], NULL, 10) > simple_strtol(ap[2], NULL, 10);
+			else if (strcmp(ap[1], "-ge") == 0)
+				expr = simple_strtol(ap[0], NULL, 10) >= simple_strtol(ap[2], NULL, 10);
+			else {
+				expr = 1;
+				break;
+			}
+
+			if (last_cmp == 0)
+				expr = last_expr || expr;
+			else if (last_cmp == 1)
+				expr = last_expr && expr;
+			last_cmp = -1;
+		}
+
+		ap += adv; left -= adv;
+	}
+
+	if (neg)
+		expr = !expr;
+
+	expr = !expr;
+
+#if 0
+	printf(": returns %d\n", expr);
+#endif
+
+	return expr;
+}
+
+U_BOOT_CMD(
+	test,	CFG_MAXARGS,	1,	do_test,
+ 	"test    - minimal test like /bin/sh\n",
+ 	"[args..]\n"
+	"    - test functionality\n"
+);
+
+int
+do_exit (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+	int r;
+
+	r = 0;
+	if (argc > 1)
+		r = simple_strtoul(argv[1], NULL, 10);
+
+	return -r - 2;
+}
+
+U_BOOT_CMD(
+	exit,	2,	1,	do_exit,
+ 	"exit    - exit script\n",
+	"    - exit functionality\n"
+);
+
+
+#endif
+
 /*
  * Use puts() instead of printf() to avoid printf buffer overflow
  * for long help messages
diff -ruNb u-boot-original/common/hush.c u-boot-parser/common/hush.c
--- u-boot-original/common/hush.c	2004-03-30 14:37:28.669930416 +0300
+++ u-boot-parser/common/hush.c	2004-03-30 15:37:59.850907000 +0300
@@ -290,6 +290,7 @@
 unsigned int global_argc;
 #endif
 unsigned int last_return_code;
+int nesting_level;
 #ifndef __U_BOOT__
 extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
 #endif
@@ -416,7 +417,9 @@
 static int b_addchr(o_string *o, int ch);
 static void b_reset(o_string *o);
 static int b_addqchr(o_string *o, int ch, int quote);
+#ifndef __U_BOOT__
 static int b_adduint(o_string *o, unsigned int i);
+#endif
 /*  in_str manipulations: */
 static int static_get(struct in_str *i);
 static int static_peek(struct in_str *i);
@@ -936,6 +939,7 @@
    return p + 1;
 }
+#ifndef __U_BOOT__
 static int b_adduint(o_string *o, unsigned int i)
 {
    int r;
@@ -944,6 +948,7 @@
    do r=b_addchr(o, *p++); while (r==0 && *p);
    return r;
 }
+#endif
static int static_get(struct in_str *i)
 {
@@ -1921,6 +1926,10 @@
    	}
    	last_return_code=rcode;
 #else
+		if (rcode < -1) {
+			last_return_code = -rcode - 2;
+			return -2;	/* exit */
+		}
    	last_return_code=(rcode == 0) ? 0 : 1;
 #endif
 #ifndef __U_BOOT__
@@ -2145,6 +2154,10 @@
 }
 #endif
+#ifdef __U_BOOT__
+static char *get_dollar_var(char ch);
+#endif
+
 /* This is used to get/check local shell variables */
 static char *get_local_var(const char *s)
 {
@@ -2152,6 +2165,12 @@
if (!s)
    	return NULL;
+
+#ifdef __U_BOOT__
+	if (*s == '$')
+		return get_dollar_var(s[1]);
+#endif
+
    for (cur = top_vars; cur; cur=cur->next)
    	if(strcmp(cur->name, s)==0)
    		return cur->value;
@@ -2168,12 +2187,19 @@
    int result=0;
    struct variables *cur;
+#ifdef __U_BOOT__
+	/* might be possible! */
+	if (!isalpha(*s))
+		return -1;
+#endif
+
    name=strdup(s);
#ifdef __U_BOOT__
    if (getenv(name) != NULL) {
    	printf ("ERROR: "
    			"There is a global environment variable with the same name.\n");
+		free(name);
    	return -1;
    }
 #endif
@@ -2278,7 +2304,10 @@
static int is_assignment(const char *s)
 {
-	if (s==NULL || !isalpha(*s)) return 0;
+	if (s == NULL)
+		return 0;
+
+	if (!isalpha(*s)) return 0;
    ++s;
    while(isalnum(*s) || *s=='_') ++s;
    return *s=='=';
@@ -2749,15 +2778,35 @@
  * see the bash man page under "Parameter Expansion" */
 static char *lookup_param(char *src)
 {
-	char *p=NULL;
-	if (src) {
+	char *p;
+
+	if (!src)
+		return NULL;
+
    	p = getenv(src);
    	if (!p)
    		p = get_local_var(src);
-	}
+
    return p;
 }
+#ifdef __U_BOOT__
+static char *get_dollar_var(char ch)
+{
+	static char buf[40];
+
+	buf[0] = '\0';
+	switch (ch) {
+		case '?':
+			sprintf(buf, "%u", (unsigned int)last_return_code);
+			break;
+		default:
+			return NULL;
+	}
+	return buf;
+}
+#endif
+
 /* return code: 0 for OK, 1 for syntax error */
 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
 {
@@ -2769,6 +2818,7 @@
 #ifndef __U_BOOT__
    char sep[]=" ";
 #endif
+	char match;
    int ch = input->peek(input);  /* first character after the $ */
    debug_printf("handle_dollar: ch=%c\n",ch);
    if (isalpha(ch)) {
@@ -2799,7 +2849,15 @@
    		break;
 #endif
    	case '?':
+#ifndef __U_BOOT__
    		b_adduint(dest,last_return_code);
+#else
+			ctx->child->sp++;
+			b_addchr(dest, SPECIAL_VAR_SYMBOL);
+			b_addchr(dest, '$');
+			b_addchr(dest, '?');
+			b_addchr(dest, SPECIAL_VAR_SYMBOL);
+#endif
    		advance = 1;
    		break;
 #ifndef __U_BOOT__
@@ -2809,14 +2867,18 @@
    		break;
 #endif
    	case '{':
+#ifdef __U_BOOT__
+		case '(':
+#endif
+			match = ch == '{' ? '}' : ')';
    		b_addchr(dest, SPECIAL_VAR_SYMBOL);
    		ctx->child->sp++;
    		b_getch(input);
    		/* XXX maybe someone will try to escape the '}' */
-			while(ch=b_getch(input),ch!=EOF && ch!='}') {
+			while(ch=b_getch(input),ch!=EOF && ch!=match) {
    			b_addchr(dest,ch);
    		}
-			if (ch != '}') {
+			if (ch != match) {
    			syntax();
    			return 1;
    		}
@@ -2885,8 +2947,10 @@
    	if (input->__promptme == 0) return 1;
 #endif
    	next = (ch == '\n') ? 0 : b_peek(input);
-		debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
-			ch,ch,m,dest->quote);
+
+		debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d - %c\n",
+			ch >= ' ' ? ch : '.',ch,m,dest->quote,ctx->stack == NULL ? '*' : '.');
+
    	if (m==0 || ((m==1 || m==2) && dest->quote)) {
    		b_addqchr(dest, ch, dest->quote);
    	} else {
@@ -3107,7 +3171,18 @@
 #ifndef __U_BOOT__
    		run_list(ctx.list_head);
 #else
-			if (((code = run_list(ctx.list_head)) == -1))
+			code = run_list(ctx.list_head);
+			if (code == -2) {	/* exit */
+				b_free(&temp);
+				code = 0;
+				/* XXX hackish way to not allow exit from main loop */
+				if (inp->peek == file_peek) {
+					printf("exit not allowed from main input shell.\n");
+					continue;
+				}
+				break;
+			}
+			if (code == -1)
    		    flag_repeat = 0;
 #endif
    	} else {

    

[U-Boot-Users] [patch #10/11] HUSH parser fixes.

Pantelis Antoniou