shared: add random-util.[ch]

Signed-off-by: Anthony G. Basile <blueness@gentoo.org>

1 files changed, 12 insertions, 102 deletions

diff --git a/src/shared/util.c b/src/shared/util.c
index d22ab8631f..0b04411f82 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -70,6 +70,7 @@
 #include "fileio.h"
 #include "virt.h"
 #include "process-util.h"
+#include "random-util.h"
 
 /* Put this test here for a lack of better place */
 assert_cc(EAGAIN == EWOULDBLOCK);
@@ -719,6 +720,17 @@ ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
         return n;
 }
 
+int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll) {
+        ssize_t n;
+
+        n = loop_read(fd, buf, nbytes, do_poll);
+        if (n < 0)
+                return n;
+        if ((size_t) n != nbytes)
+                return -EIO;
+        return 0;
+}
+
 char* dirname_malloc(const char *path) {
         char *d, *dir, *dir2;
 
@@ -737,108 +749,6 @@ char* dirname_malloc(const char *path) {
         return dir;
 }
 
-int dev_urandom(void *p, size_t n) {
-        static int have_syscall = -1;
-        int r, fd;
-        ssize_t k;
-
-        /* Gathers some randomness from the kernel. This call will
-         * never block, and will always return some data from the
-         * kernel, regardless if the random pool is fully initialized
-         * or not. It thus makes no guarantee for the quality of the
-         * returned entropy, but is good enough for or usual usecases
-         * of seeding the hash functions for hashtable */
-
-        /* Use the getrandom() syscall unless we know we don't have
-         * it, or when the requested size is too large for it. */
-        if (have_syscall != 0 || (size_t) (int) n != n) {
-                r = getrandom(p, n, GRND_NONBLOCK);
-                if (r == (int) n) {
-                        have_syscall = true;
-                        return 0;
-                }
-
-                if (r < 0) {
-                        if (errno == ENOSYS)
-                                /* we lack the syscall, continue with
-                                 * reading from /dev/urandom */
-                                have_syscall = false;
-                        else if (errno == EAGAIN)
-                                /* not enough entropy for now. Let's
-                                 * remember to use the syscall the
-                                 * next time, again, but also read
-                                 * from /dev/urandom for now, which
-                                 * doesn't care about the current
-                                 * amount of entropy.  */
-                                have_syscall = true;
-                        else
-                                return -errno;
-                } else
-                        /* too short read? */
-                        return -EIO;
-        }
-
-        fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
-        if (fd < 0)
-                return errno == ENOENT ? -ENOSYS : -errno;
-
-        k = loop_read(fd, p, n, true);
-        safe_close(fd);
-
-        if (k < 0)
-                return (int) k;
-        if ((size_t) k != n)
-                return -EIO;
-
-        return 0;
-}
-
-void initialize_srand(void) {
-        static bool srand_called = false;
-        unsigned x;
-#ifdef HAVE_SYS_AUXV_H
-        void *auxv;
-#endif
-
-        if (srand_called)
-                return;
-
-        x = 0;
-
-#ifdef HAVE_SYS_AUXV_H
-        /* The kernel provides us with a bit of entropy in auxv, so
-         * let's try to make use of that to seed the pseudo-random
-         * generator. It's better than nothing... */
-
-        auxv = (void*) getauxval(AT_RANDOM);
-        if (auxv)
-                x ^= *(unsigned*) auxv;
-#endif
-
-        x ^= (unsigned) now(CLOCK_REALTIME);
-        x ^= (unsigned) gettid();
-
-        srand(x);
-        srand_called = true;
-}
-
-void random_bytes(void *p, size_t n) {
-        uint8_t *q;
-        int r;
-
-        r = dev_urandom(p, n);
-        if (r >= 0)
-                return;
-
-        /* If some idiot made /dev/urandom unavailable to us, he'll
-         * get a PRNG instead. */
-
-        initialize_srand();
-
-        for (q = p; q < (uint8_t*) p + n; q ++)
-                *q = rand();
-}
-
 _pure_ static int is_temporary_fs(struct statfs *s) {
         assert(s);