comment potentially-confusing use of struct crypt_data type

diff --git a/src/crypt/crypt.c b/src/crypt/crypt.c
index f1e310f..4650073 100644 (file)
--- a/src/crypt/crypt.c
+++ b/src/crypt/crypt.c
@@ -5,7 +5,12 @@ char *__crypt_r(const char *, const char *, struct crypt_data *);
 
 char *crypt(const char *key, const char *salt)
 {
 
 char *crypt(const char *key, const char *salt)
 {

-       /* Note: update this size when we add more hash types */
+       /* This buffer is sufficiently large for all
+        * currently-supported hash types. It needs to be updated if
+        * longer hashes are added. The cast to struct crypt_data * is
+        * purely to meet the public API requirements of the crypt_r
+        * function; the implementation of crypt_r uses the object
+        * purely as a char buffer. */

        static char buf[128];
        return __crypt_r(key, salt, (struct crypt_data *)buf);
 }
        static char buf[128];
        return __crypt_r(key, salt, (struct crypt_data *)buf);
 }

diff --git a/src/crypt/crypt_r.c b/src/crypt/crypt_r.c
index 3257e8b..5982c4c 100644 (file)
--- a/src/crypt/crypt_r.c
+++ b/src/crypt/crypt_r.c
@@ -11,6 +11,10 @@ char *__crypt_sha512(const char *, const char *, char *);
 
 char *__crypt_r(const char *key, const char *salt, struct crypt_data *data)
 {
 
 char *__crypt_r(const char *key, const char *salt, struct crypt_data *data)
 {

+       /* Per the crypt_r API, the caller has provided a pointer to
+        * struct crypt_data; however, this implementation does not
+        * use the structure to store any internal state, and treats
+        * it purely as a char buffer for storing the result. */

        char *output = (char *)data;
        if (salt[0] == '$' && salt[1] && salt[2]) {
                if (salt[1] == '1' && salt[2] == '$')
        char *output = (char *)data;
        if (salt[0] == '$' && salt[1] && salt[2]) {
                if (salt[1] == '1' && salt[2] == '$')