Message-ID: <20180310105659.7e34lk4kvcbl64lg@gmail.com>
Date:   Sat, 10 Mar 2018 00:56:59 -1000
From:   Joey Pabalinas <joeypabalinas@...il.com>
To:     linux-kbuild@...r.kernel.org
Cc:     Ulf Magnusson <ulfalizer@...il.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-kernel@...r.kernel.org,
        Joey Pabalinas <joeypabalinas@...il.com>
Subject: [PATCH v2] scripts/kconfig: cleanup symbol handling code

Many of the variable names in scripts/kconfig/symbol.c are
far too terse to the point of not at all identifying _what_
they are actually used for (`p` and `l` as a couple examples),
and overall there is a large amount of code that could use
some cleaning up.

Give more explicit names to these variables, fix a couple cases
where different variables were sharing the same name and shadowing
each other, and overall cleanup a bit of the messiness in
sym_expand_string_value() and sym_escape_string_value()
while maintaining equivalent program behavior.

Suggested-by: Ulf Magnusson <ulfalizer@...il.com>
Signed-off-by: Joey Pabalinas <joeypabalinas@...il.com>

 1 file changed, 69 insertions(+), 61 deletions(-)

diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index 2220bc4b051bd914e3..9ee32ddb44e193719c 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -5,8 +5,8 @@
 
 #include <ctype.h>
 #include <stdlib.h>
-#include <string.h>
 #include <regex.h>
+#include <linux/string.h>
 #include <sys/utsname.h>
 
 #include "lkc.h"
@@ -337,7 +337,7 @@ void sym_calc_value(struct symbol *sym)
 {
 	struct symbol_value newval, oldval;
 	struct property *prop;
-	struct expr *e;
+	struct expr *expr;
 
 	if (!sym)
 		return;
@@ -469,7 +469,7 @@ void sym_calc_value(struct symbol *sym)
 		struct symbol *choice_sym;
 
 		prop = sym_get_choice_prop(sym);
-		expr_list_for_each_sym(prop->expr, e, choice_sym) {
+		expr_list_for_each_sym(prop->expr, expr, choice_sym) {
 			if ((sym->flags & SYMBOL_WRITE) &&
 			    choice_sym->visible != no)
 				choice_sym->flags |= SYMBOL_WRITE;
@@ -899,94 +899,100 @@ struct symbol *sym_find(const char *name)
  * name to be expanded shall be prefixed by a '$'. Unknown symbol expands to
  * the empty string.
  */
-char *sym_expand_string_value(const char *in)
+char *sym_expand_string_value(const char *src)
 {
-	const char *src;
-	char *res;
-	size_t reslen;
+	const char *in;
+	char *res, *out;
+	size_t res_len, src_len;
 
 	/*
-	 * Note: 'in' might come from a token that's about to be
+	 * Note: 'src' might come from a token that'src about to be
 	 * freed, so make sure to always allocate a new string
 	 */
-	reslen = strlen(in) + 1;
-	res = xmalloc(reslen);
-	res[0] = '\0';
+	res_len = strlen(src) + 1;
+	res = xmalloc(res_len);
+	out = res;
 
-	while ((src = strchr(in, '$'))) {
+	while ((in = strchr(src, '$'))) {
 		char *p, name[SYMBOL_MAXLENGTH];
-		const char *symval = "";
+		const char *sym_val = "";
 		struct symbol *sym;
-		size_t newlen;
+		size_t new_len, sym_len;
 
-		strncat(res, in, src - in);
-		src++;
+		strscpy(out, src, in - src);
+		out += in - src;
+		in++;
 
 		p = name;
-		while (isalnum(*src) || *src == '_')
-			*p++ = *src++;
+		while (isalnum(*in) || *in == '_')
+			*p++ = *in++;
 		*p = '\0';
 
 		sym = sym_find(name);
 		if (sym != NULL) {
 			sym_calc_value(sym);
-			symval = sym_get_string_value(sym);
+			sym_val = sym_get_string_value(sym);
 		}
 
-		newlen = strlen(res) + strlen(symval) + strlen(src) + 1;
-		if (newlen > reslen) {
-			reslen = newlen;
-			res = xrealloc(res, reslen);
+		sym_len = strlen(sym_val);
+		new_len = sym_len + strlen(res) + strlen(in) + 1;
+		if (new_len > res_len) {
+			res_len = new_len;
+			res = xrealloc(res, res_len);
 		}
 
-		strcat(res, symval);
-		in = src;
+		strscpy(out, sym_val, sym_len);
+		out += sym_len;
+		src = in;
 	}
-	strcat(res, in);
+	src_len = strlen(src);
+	strscpy(out, src, src_len);
+	out += src_len;
+	*out = '\0';
 
 	return res;
 }
 
-const char *sym_escape_string_value(const char *in)
+const char *sym_escape_string_value(const char *src)
 {
-	const char *p;
-	size_t reslen;
-	char *res;
-	size_t l;
+	const char *in;
+	size_t res_len, in_len;
+	char *res, *out;
 
-	reslen = strlen(in) + strlen("\"\"") + 1;
+	res_len = strlen(src) + strlen("\"\"") + 1;
 
-	p = in;
+	in = src;
 	for (;;) {
-		l = strcspn(p, "\"\\");
-		p += l;
+		in_len = strcspn(in, "\"\\");
+		in += in_len;
 
-		if (p[0] == '\0')
+		if (*in == '\0')
 			break;
 
-		reslen++;
-		p++;
+		res_len++;
+		in++;
 	}
 
-	res = xmalloc(reslen);
-	res[0] = '\0';
+	res = xmalloc(res_len);
+	out = res;
+	*out++ = '\"';
 
-	strcat(res, "\"");
-
-	p = in;
+	in = src;
 	for (;;) {
-		l = strcspn(p, "\"\\");
-		strncat(res, p, l);
-		p += l;
+		in_len = strcspn(in, "\"\\");
+		strscpy(out, in, in_len);
+		in += in_len;
+		out += in_len;
 
-		if (p[0] == '\0')
+		if (*in == '\0')
 			break;
 
-		strcat(res, "\\");
-		strncat(res, p++, 1);
+		*out++ = '\\';
+		*out++ = *in++;
 	}
+	*out++ = '\"';
+	*out = '\0';
 
-	strcat(res, "\"");
 	return res;
 }
 
@@ -1014,8 +1020,8 @@ static int sym_rel_comp(const void *sym1, const void *sym2)
 	 * exactly; if this is the case, we can't decide which comes first,
 	 * and we fallback to sorting alphabetically.
 	 */
-	exact1 = (s1->eo - s1->so) == strlen(s1->sym->name);
-	exact2 = (s2->eo - s2->so) == strlen(s2->sym->name);
+	exact1 = (s1->eo - s1->so) == (off_t)strlen(s1->sym->name);
+	exact2 = (s2->eo - s2->so) == (off_t)strlen(s2->sym->name);
 	if (exact1 && !exact2)
 		return -1;
 	if (!exact1 && exact2)
@@ -1390,31 +1396,33 @@ const char *prop_get_type_name(enum prop_type type)
 	return "unknown";
 }
 
-static void prop_add_env(const char *env)
+static void prop_add_env(const char *env_key)
 {
 	struct symbol *sym, *sym2;
 	struct property *prop;
-	char *p;
+	char *env_val;
 
 	sym = current_entry->sym;
 	sym->flags |= SYMBOL_AUTO;
 	for_all_properties(sym, prop, P_ENV) {
 		sym2 = prop_get_symbol(prop);
-		if (strcmp(sym2->name, env))
+		if (strcmp(sym2->name, env_key))
 			menu_warn(current_entry, "redefining environment symbol from %s",
 				  sym2->name);
 		return;
 	}
 
 	prop = prop_alloc(P_ENV, sym);
-	prop->expr = expr_alloc_symbol(sym_lookup(env, SYMBOL_CONST));
+	prop->expr = expr_alloc_symbol(sym_lookup(env_key, SYMBOL_CONST));
 
 	sym_env_list = expr_alloc_one(E_LIST, sym_env_list);
 	sym_env_list->right.sym = sym;
+	env_val = getenv(env_key);
 
-	p = getenv(env);
-	if (p)
-		sym_add_default(sym, p);
-	else
-		menu_warn(current_entry, "environment variable %s undefined", env);
+	if (likely(env_val)) {
+		sym_add_default(sym, env_val);
+		return;
+	}
+
+	menu_warn(current_entry, "environment variable %s undefined", env_key);
 }
-- 
2.16.2

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