Add missing comment for the offset argument of tokenize. Add error checko on the offset.

libc/inc/string.h

@@ -174,6 +174,7 @@ char *strtok_r(char *str, const char *delim, char **saveptr);
 /// parsed token in buffer. The pointer `string` will be modified.
 /// @param string cursor used to parse the string, it will be modified.
 /// @param separators the list of separators we are using.
+/// @param offset the offset character from which we start extracting the next token.
 /// @param buffer the buffer where we save the parsed token.
 /// @param buflen the length of the buffer.
 /// @return 1 if we still have things to parse, 0 if we finished parsing.

libc/inc/sys/unistd.h

@@ -61,7 +61,7 @@ int unlink(const char *path);
 int symlink(const char *linkname, const char *path);
 
 /// @brief Read the symbolic link, if present.
-/// @param file the file for which we want to read the symbolic link information.
+/// @param path the file for which we want to read the symbolic link information.
 /// @param buffer the buffer where we will store the symbolic link path.
 /// @param bufsize the size of the buffer.
 /// @return The number of read characters on success, -1 otherwise and errno is set to indicate the error.

libc/src/string.c

@@ -221,7 +221,7 @@ char *strpbrk(const char *string, const char *control)
 int tokenize(const char *string, char *separators, size_t *offset, char *buffer, ssize_t buflen)
 {
     // If we reached the end of the parsed string, stop.
-    if (string[*offset] == 0) {
+    if ((*offset >= buflen) || (string[*offset] == 0)) {
         return 0;
     }
     // Keep copying character until we either reach 1) the end of the buffer, 2) a
@@ -238,7 +238,8 @@ int tokenize(const char *string, char *separators, size_t *offset, char *buffer,
         }
         // Save the character.
         *buffer = string[*offset];
-        // Advance the offset, decrese the available size in the buffer, and advance the buffer.
+        // Advance the offset, decrese the available size in the buffer, and advance
+        // the buffer.
         ++(*offset), --buflen, ++buffer;
     } while ((buflen > 0) && (string[*offset] != 0));
     // Close the buffer.

mentos/src/klib/string.c

@@ -221,7 +221,7 @@ char *strpbrk(const char *string, const char *control)
 int tokenize(const char *string, char *separators, size_t *offset, char *buffer, ssize_t buflen)
 {
     // If we reached the end of the parsed string, stop.
-    if (string[*offset] == 0) {
+    if ((*offset >= buflen) || (string[*offset] == 0)) {
         return 0;
     }
     // Keep copying character until we either reach 1) the end of the buffer, 2) a