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GUACAMOLE-637: Correctly handle string lengths as size_t (unsigned).

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This commit is contained in:
Michael Jumper 2019-01-06 15:03:54 -08:00
parent 068f33aaef
commit 258946cd88
1 changed files with 26 additions and 6 deletions
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32
src/libguac/string.c
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@ -22,6 +22,26 @@
#include <stddef.h> #include <stddef.h>
#include <string.h> #include <string.h>
/**
* Returns the space remaining in a buffer assuming that the given number of
* bytes have already been written. If the number of bytes exceeds the size
* of the buffer, zero is returned.
*
* @param n
* The size of the buffer in bytes.
*
* @param length
* The number of bytes which have been written to the buffer so far. If
* the routine writing the bytes will automatically truncate its writes,
* this value may exceed the size of the buffer.
*
* @return
* The number of bytes remaining in the buffer. This value will always
* be non-negative. If the number of bytes written already exceeds the
* size of the buffer, zero will be returned.
*/
#define REMAINING(n, length) (((n) < (length)) ? 0 : ((n) - (length)))
size_t guac_strlcpy(char* restrict dest, const char* restrict src, size_t n) { size_t guac_strlcpy(char* restrict dest, const char* restrict src, size_t n) {
#ifdef HAVE_STRLCPY #ifdef HAVE_STRLCPY
@ -31,7 +51,7 @@ size_t guac_strlcpy(char* restrict dest, const char* restrict src, size_t n) {
size_t length = strlen(src); size_t length = strlen(src);
/* Copy nothing if there is no space */ /* Copy nothing if there is no space */
if (n <= 0) if (n == 0)
return length; return length;
/* Calculate length of the string which will be copied */ /* Calculate length of the string which will be copied */
@ -55,8 +75,8 @@ size_t guac_strlcat(char* restrict dest, const char* restrict src, size_t n) {
#ifdef HAVE_STRLCPY #ifdef HAVE_STRLCPY
return strlcat(dest, src, n); return strlcat(dest, src, n);
#else #else
int length = strnlen(dest, n); size_t length = strnlen(dest, n);
return length + guac_strlcpy(dest + length, src, n - length); return length + guac_strlcpy(dest + length, src, REMAINING(n, length));
#endif #endif
} }
@ -64,7 +84,7 @@ size_t guac_strlcat(char* restrict dest, const char* restrict src, size_t n) {
size_t guac_strljoin(char* restrict dest, const char* restrict const* elements, size_t guac_strljoin(char* restrict dest, const char* restrict const* elements,
int nmemb, const char* restrict delim, size_t n) { int nmemb, const char* restrict delim, size_t n) {
int length = 0; size_t length = 0;
const char* restrict const* current = elements; const char* restrict const* current = elements;
/* If no elements are provided, nothing to do but ensure the destination /* If no elements are provided, nothing to do but ensure the destination
@ -77,8 +97,8 @@ size_t guac_strljoin(char* restrict dest, const char* restrict const* elements,
/* Copy all remaining elements, separated by delimiter */ /* Copy all remaining elements, separated by delimiter */
for (current++; nmemb > 1; current++, nmemb--) { for (current++; nmemb > 1; current++, nmemb--) {
length += guac_strlcat(dest + length, delim, n - length); length += guac_strlcat(dest + length, delim, REMAINING(n, length));
length += guac_strlcat(dest + length, *current, n - length); length += guac_strlcat(dest + length, *current, REMAINING(n, length));
} }
return length; return length;