Avoid undefined behaviour with the ctype(3) functions.

fix https://github.com/pkgconf/pkgconf/issues/291

As defined in the C standard:

        In all cases the argument is an int, the value of which shall
        be representable as an unsigned char or shall equal the value
        of the macro EOF.  If the argument has any other value, the
        behavior is undefined.

This is because they're designed to work with the int values returned
by getc or fgetc; they need extra work to handle a char value.

If EOF is -1 (as it almost always is), with 8-bit bytes, the allowed
inputs to the ctype(3) functions are:

        {-1, 0, 1, 2, 3, ..., 255}.

However, on platforms where char is signed, such as x86 with the
usual ABI, code like

        char *ptr = ...;
        ... isspace(*ptr) ...

may pass in values in the range:

        {-128, -127, -126, ..., -2, -1, 0, 1, ..., 127}.

This has two problems:

1. Inputs in the set {-128, -127, -126, ..., -2} are forbidden.

2. The non-EOF byte 0xff is conflated with the value EOF = -1, so
   even though the input is not forbidden, it may give the wrong
   answer.

Casting char to unsigned int first before passing the result to
ctype(3) doesn't help: inputs like -128 are unchanged by this cast,
because (on a two's-complement machine with 32-bit int and unsigned
int), converting the signed char with integer value -128 to unsigned
int gives integer value 2^32 - 128 = 0xffffff80, which is out of
range, and which is converted in int back to -128, which is also out
of range.

It is necessary to cast char inputs to unsigned char first; you can
then cast to unsigned int if you like but there's no need because the
functions will always convert the argument to int by definition.  So
the above fragment needs to be:

        char *ptr = ...;
        ... isspace((unsigned char)*ptr) ...

This patch changes unsigned int casts to unsigned char casts, and
adds unsigned char casts where they are missing.

cli/bomtool/main.c

@@ -309,7 +309,7 @@ main(int argc, char *argv[])
 		if (maximum_package_count > 0 && pkgq.length > maximum_package_count)
 			break;
 
-		while (isspace((unsigned int)package[0]))
+		while (isspace((unsigned char)package[0]))
 			package++;
 
 		/* skip empty packages */

cli/main.c

@@ -407,7 +407,8 @@ apply_env(pkgconf_client_t *client, pkgconf_pkg_t *world, void *env_prefix_p, in
 	char workbuf[PKGCONF_ITEM_SIZE];
 
 	for (it = want_env_prefix; *it != '\0'; it++)
-		if (!isalpha(*it) && !isdigit(*it))
+		if (!isalpha((unsigned char)*it) &&
+		    !isdigit((unsigned char)*it))
 			return false;
 
 	snprintf(workbuf, sizeof workbuf, "%s_CFLAGS", want_env_prefix);
@@ -1327,7 +1328,7 @@ cleanup3:
 		if (maximum_package_count > 0 && pkgq.length > maximum_package_count)
 			break;
 
-		while (isspace((unsigned int)package[0]))
+		while (isspace((unsigned char)package[0]))
 			package++;
 
 		/* skip empty packages */

libpkgconf/argvsplit.c

@@ -108,7 +108,7 @@ pkgconf_argv_split(const char *src, int *argc, char ***argv)
 			else
 				*dst_iter++ = *src_iter;
 		}
-		else if (isspace((unsigned int)*src_iter))
+		else if (isspace((unsigned char)*src_iter))
 		{
 			if ((*argv)[argc_count] != NULL)
 			{

libpkgconf/dependency.c

@@ -329,11 +329,11 @@ pkgconf_dependency_parse_str(pkgconf_client_t *client, pkgconf_list_t *deplist_h
 			break;
 
 		case INSIDE_MODULE_NAME:
-			if (isspace((unsigned int)*ptr))
+			if (isspace((unsigned char)*ptr))
 			{
 				const char *sptr = ptr;
 
-				while (*sptr && isspace((unsigned int)*sptr))
+				while (*sptr && isspace((unsigned char)*sptr))
 					sptr++;
 
 				if (*sptr == '\0')
@@ -397,7 +397,7 @@ pkgconf_dependency_parse_str(pkgconf_client_t *client, pkgconf_list_t *deplist_h
 			break;
 
 		case AFTER_OPERATOR:
-			if (!isspace((unsigned int)*ptr))
+			if (!isspace((unsigned char)*ptr))
 			{
 				vstart = ptr;
 				state = INSIDE_VERSION;

libpkgconf/libpkgconf.h

@@ -249,7 +249,7 @@ PKGCONF_API pkgconf_cross_personality_t *pkgconf_cross_personality_default(void)
 PKGCONF_API pkgconf_cross_personality_t *pkgconf_cross_personality_find(const char *triplet);
 PKGCONF_API void pkgconf_cross_personality_deinit(pkgconf_cross_personality_t *personality);
 
-#define PKGCONF_IS_MODULE_SEPARATOR(c) ((c) == ',' || isspace ((unsigned int)(c)))
+#define PKGCONF_IS_MODULE_SEPARATOR(c) ((c) == ',' || isspace ((unsigned char)(c)))
 #define PKGCONF_IS_OPERATOR_CHAR(c) ((c) == '<' || (c) == '>' || (c) == '!' || (c) == '=')
 
 #define PKGCONF_PKG_PKGF_NONE				0x0000

libpkgconf/parser.c

@@ -44,7 +44,7 @@ pkgconf_parser_parse(FILE *f, void *data, const pkgconf_parser_operand_func_t *o
 		lineno++;
 
 		p = readbuf;
-		while (*p && isspace((unsigned int)*p))
+		while (*p && isspace((unsigned char)*p))
 			p++;
 		if (*p && p != readbuf)
 		{
@@ -53,13 +53,14 @@ pkgconf_parser_parse(FILE *f, void *data, const pkgconf_parser_operand_func_t *o
 			warned_key_whitespace = true;
 		}
 		key = p;
-		while (*p && (isalpha((unsigned int)*p) || isdigit((unsigned int)*p) || *p == '_' || *p == '.'))
+		while (*p && (isalpha((unsigned char)*p) || isdigit((unsigned char)*p) || *p == '_' || *p == '.'))
 			p++;
 
-		if (!isalpha((unsigned int)*key) && !isdigit((unsigned int)*p))
+		if (!isalpha((unsigned char)*key) &&
+		    !isdigit((unsigned char)*p))
 			continue;
 
-		while (*p && isspace((unsigned int)*p))
+		while (*p && isspace((unsigned char)*p))
 		{
 			if (!warned_key_whitespace)
 			{
@@ -80,12 +81,12 @@ pkgconf_parser_parse(FILE *f, void *data, const pkgconf_parser_operand_func_t *o
 			p++;
 		}
 
-		while (*p && isspace((unsigned int)*p))
+		while (*p && isspace((unsigned char)*p))
 			p++;
 
 		value = p;
 		p = value + (strlen(value) - 1);
-		while (*p && isspace((unsigned int) *p) && p > value)
+		while (*p && isspace((unsigned char) *p) && p > value)
 		{
 			if (!warned_value_whitespace && op == '=')
 			{

libpkgconf/personality.c

@@ -148,7 +148,7 @@ valid_triplet(const char *triplet)
 	const char *c = triplet;
 
 	for (; *c; c++)
-		if (!isalnum(*c) && *c != '-' && *c != '_')
+		if (!isalnum((unsigned char)*c) && *c != '-' && *c != '_')
 			return false;
 
 	return true;

libpkgconf/pkg.c

@@ -857,9 +857,9 @@ pkgconf_compare_version(const char *a, const char *b)
 
 	while (*one || *two)
 	{
-		while (*one && !isalnum((unsigned int)*one) && *one != '~')
+		while (*one && !isalnum((unsigned char)*one) && *one != '~')
 			one++;
-		while (*two && !isalnum((unsigned int)*two) && *two != '~')
+		while (*two && !isalnum((unsigned char)*two) && *two != '~')
 			two++;
 
 		if (*one == '~' || *two == '~')
@@ -880,22 +880,22 @@ pkgconf_compare_version(const char *a, const char *b)
 		str1 = one;
 		str2 = two;
 
-		if (isdigit((unsigned int)*str1))
+		if (isdigit((unsigned char)*str1))
 		{
-			while (*str1 && isdigit((unsigned int)*str1))
+			while (*str1 && isdigit((unsigned char)*str1))
 				str1++;
 
-			while (*str2 && isdigit((unsigned int)*str2))
+			while (*str2 && isdigit((unsigned char)*str2))
 				str2++;
 
 			isnum = true;
 		}
 		else
 		{
-			while (*str1 && isalpha((unsigned int)*str1))
+			while (*str1 && isalpha((unsigned char)*str1))
 				str1++;
 
-			while (*str2 && isalpha((unsigned int)*str2))
+			while (*str2 && isalpha((unsigned char)*str2))
 				str2++;
 
 			isnum = false;

libpkgconf/win-dirent.h

@@ -912,7 +912,7 @@ static int strverscmp(const char *a, const char *b)
 
 	/* Count backwards and find the leftmost digit */
 	j = i;
-	while (j > 0 && isdigit(a[j-1])) {
+	while (j > 0 && isdigit((unsigned char)a[j-1])) {
 		--j;
 	}
 
@@ -924,23 +924,24 @@ static int strverscmp(const char *a, const char *b)
 		}
 
 		/* String with more digits is smaller, e.g 002 < 01 */
-		if (isdigit(a[j])) {
-			if (!isdigit(b[j])) {
+		if (isdigit((unsigned char)a[j])) {
+			if (!isdigit((unsigned char)b[j])) {
 				return -1;
 			}
-		} else if (isdigit(b[j])) {
+		} else if ((unsigned char)isdigit(b[j])) {
 			return 1;
 		}
-	} else if (isdigit(a[j]) && isdigit(b[j])) {
+	} else if ((unsigned char)isdigit(a[j]) &&
+	    isdigit((unsigned char)b[j])) {
 		/* Numeric comparison */
 		size_t k1 = j;
 		size_t k2 = j;
 
 		/* Compute number of digits in each string */
-		while (isdigit(a[k1])) {
+		while (isdigit((unsigned char)a[k1])) {
 			k1++;
 		}
-		while (isdigit(b[k2])) {
+		while (isdigit((unsigned char)b[k2])) {
 			k2++;
 		}
 

tests/lib1/utf8.pc

@@ -0,0 +1,10 @@
+prefix=/tëst
+exec_prefix=${prefix}
+libdir=${prefix}/lib
+includedir=${prefix}/include
+
+Name: utf8
+Description: Library installed in a prefix with UTF-8
+Version: 0
+Libs: -L${libdir} -lutf8
+Cflags: -I${includedir}