Hello All,
This mail is in reference to one of the tasks mentioned in 'Contribute/BiteSizedTasks' in QEMU wiki, under 'API conversion' which states to introduce a better alternative to strncpy function. I've drafted and tested below implementation for the same. Before proceeding with any changes in QEMU code can you all please go through it and suggest changes/corrections if required.
/* This function is introduced in place of strncpy(), it asserts if destination
* is large enough to fit strlen(source)+1 bytes and guarantees null termination
* in destination string.
*
* char source[], is expecting a pointer to the source where data should be copied
* from.
*
* char destination[], is expecting a pointer to the destination where data should
* be copied to.
*
* size_t destination_size, is expecting size of destination.
* In case of char[], sizeof() function can be used to find the size.
* In case of char *, provide value which was passed to malloc() function for
* memory allocation.
*/
char *qemu_strncpy(char destination[], char source[], size_t destination_size)
{
/* Looping through the array and copying the characters from
* source to destination.
*/
for (int i = 0; i < strlen(source); i++) {
destination[i] = source[i];
/* Check if value of i is equal to the second last index
* of destination array and if condition is true, mark last
* index as NULL and break from the loop.
*/
if (i == (destination_size - 2)) {
destination[destination_size - 1] = '\0';
break;
}
}
return destination;
}
/* This function is introduced in place of strncpy(), it asserts if destination
* is large enough to fit strlen(source) bytes and does not guarantee null
* termination in destination string.
*
* char source[], is expecting a pointer to the source where data should be copied
* from.
*
* char destination[], is expecting a pointer to the destination where data should
* be copied to.
*
* size_t destination_size, is expecting size of destination.
* In case of char[], sizeof() function can be used to find the size.
* In case of char *, provide value which was passed to malloc() function for
* memory allocation.
*/
char *qemu_strncpy_nonul(char destination[], char source[], size_t destination_size)
{
/* Looping through the array and copying the characters from
* source to destination.
*/
for (int i = 0; i < strlen(source); i++) {
destination[i] = source[i];
/* Check if value of i is equal to the last index
* of the destination array and if condition is true,
* break from the loop.
*/
if (i == (destination_size - 1)) {
break;
}
}
return destination;
}
Regards,
Chetan P.