Avoid allocating packet buffers unnecessarily.

[meshlink] / src / crypto.c

diff --git a/src/crypto.c b/src/crypto.c
index e3797f8d79d04a0c8e8341786693e2fcc365979a..3244a0b4628bdd2e6ddb6f49dbf1a0c30fab17ad 100644 (file)
--- a/src/crypto.c
+++ b/src/crypto.c
@@ -28,9 +28,14 @@
 static int random_fd = -1;
 
 void crypto_init(void) {
+       assert(random_fd == -1);
+
        random_fd = open("/dev/urandom", O_RDONLY);
-       if(random_fd < 0)
+
+       if(random_fd < 0) {
                random_fd = open("/dev/random", O_RDONLY);
+       }
+
        if(random_fd < 0) {
                fprintf(stderr, "Could not open source of random numbers: %s\n", strerror(errno));
                abort();
@@ -38,19 +43,30 @@ void crypto_init(void) {
 }
 
 void crypto_exit(void) {
+       assert(random_fd != -1);
+
        close(random_fd);
+       random_fd = -1;
 }
 
 void randomize(void *out, size_t outlen) {
+       assert(outlen);
+
+       char *ptr = out;
+
        while(outlen) {
-               size_t len = read(random_fd, out, outlen);
+               size_t len = read(random_fd, ptr, outlen);
+
                if(len <= 0) {
-                       if(errno == EAGAIN || errno == EINTR)
+                       if(errno == EAGAIN || errno == EINTR) {
                                continue;
+                       }
+
                        fprintf(stderr, "Could not read random numbers: %s\n", strerror(errno));
                        abort();
                }
-               out += len;
+
+               ptr += len;
                outlen -= len;
        }
 }
@@ -72,6 +88,8 @@ void crypto_exit(void) {
 }
 
 void randomize(void *out, size_t outlen) {
+       assert(outlen);
+
        if(!CryptGenRandom(prov, outlen, out)) {
                fprintf(stderr, "CryptGenRandom() failed\n");
                abort();