[SLOF] [PATCH slof 02/13] libc: Compile with -Wextra

[Thomas Huth]

On 27/01/2021 09.57, Alexey Kardashevskiy wrote:
> -Wextra enables a bunch of rather useful checks which this fixes.
> 
> Signed-off-by: Alexey Kardashevskiy <aik at ozlabs.ru>
> ---
>   lib/libc/stdio/vsnprintf.c | 15 ++++++++-------
>   lib/libc/string/memmove.c  |  2 +-
>   2 files changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/lib/libc/stdio/vsnprintf.c b/lib/libc/stdio/vsnprintf.c
> index 21dd04dfe46f..1a44301f74da 100644
> --- a/lib/libc/stdio/vsnprintf.c
> +++ b/lib/libc/stdio/vsnprintf.c
> @@ -25,15 +25,15 @@ static int
>   print_str_fill(char **buffer, size_t bufsize, char *sizec,
>   					const char *str, char c)
>   {
> -	int i, sizei, len;
> +	unsigned i, sizei, len;
>   	char *bstart = *buffer;
>   
>   	sizei = strtoul(sizec, NULL, 10);
>   	len = strlen(str);
>   	if (sizei > len) {
>   		for (i = 0;
> -			(i < (sizei - len)) && ((*buffer - bstart) < bufsize);
> -									i++) {
> +			(i < (sizei - len)) && ((*buffer - bstart) < (int)bufsize);

bufsize is of type size_t, so the correct way to cast would be "(ssize_t)" 
instead of "(int)", I think.
Maybe it would also be worth the effort to introduce a new local variable a la:

  ssize_t sbufsize = (ssize_t)bufsize;

so that you don't have to do the cast again and again all over the place?

  Thomas


> +			i++) {
>   			**buffer = c;
>   			*buffer += 1;
>   		}
> @@ -47,7 +47,7 @@ print_str(char **buffer, size_t bufsize, const char *str)
>   	char *bstart = *buffer;
>   	size_t i;
>   
> -	for (i = 0; (i < strlen(str)) && ((*buffer - bstart) < bufsize); i++) {
> +	for (i = 0; (i < strlen(str)) && ((*buffer - bstart) < (int)bufsize); i++) {
>   		**buffer = str[i];
>   		*buffer += 1;
>   	}
> @@ -112,7 +112,7 @@ print_fill(char **buffer, size_t bufsize, char *sizec, unsigned long size,
>    	len = print_intlen(size, base) + optlen;
>   	if (sizei > len) {
>   		for (i = 0;
> -			(i < (sizei - len)) && ((*buffer - bstart) < bufsize);
> +			(i < (sizei - len)) && ((*buffer - bstart) < (int)bufsize);
>   									i++) {
>   			**buffer = c;
>   			*buffer += 1;
> @@ -143,7 +143,7 @@ print_format(char **buffer, size_t bufsize, const char *format, void *var)
>   		form++;
>   	}
>   
> -	while ((*form != '\0') && ((*buffer - start) < bufsize)) {
> +	while ((*form != '\0') && ((*buffer - start) < (int)bufsize)) {
>   		switch(*form) {
>   			case 'u':
>   			case 'd':
> @@ -163,6 +163,7 @@ print_format(char **buffer, size_t bufsize, const char *format, void *var)
>   				break;
>   			case 'X':
>   				upper = true;
> +				/* fallthrough */
>   			case 'x':
>   				sizec[i] = '\0';
>   				value = (unsigned long) var & convert[length_mod];
> @@ -260,7 +261,7 @@ vsnprintf(char *buffer, size_t bufsize, const char *format, va_list arg)
>   	/* Leave one space for NULL character */
>   	bufsize--;
>   
> -	while(*ptr != '\0' && (buffer - bstart) < bufsize)
> +	while(*ptr != '\0' && (buffer - bstart) < (int)bufsize)
>   	{
>   		if(*ptr == '%') {
>   			char formstr[20];
> diff --git a/lib/libc/string/memmove.c b/lib/libc/string/memmove.c
> index 3acf1a973bbe..9d0962847296 100644
> --- a/lib/libc/string/memmove.c
> +++ b/lib/libc/string/memmove.c
> @@ -18,7 +18,7 @@ memmove(void *dest, const void *src, size_t n)
>   {
>   	char *cdest;
>   	const char *csrc;
> -	int i;
> +	size_t i;
>   
>   	/* Do the buffers overlap in a bad way? */
>   	if (src < dest && src + n >= dest) {
>