+# endif
+}
+# endif /* defined(OPENSSL_RAND_SEED_GETRANDOM) */
+
+# if defined(OPENSSL_RAND_SEED_DEVRANDOM)
+static const char *random_device_paths[] = { DEVRANDOM };
+static struct random_device {
+ int fd;
+ dev_t dev;
+ ino_t ino;
+ mode_t mode;
+ dev_t rdev;
+} random_devices[OSSL_NELEM(random_device_paths)];
+static int keep_random_devices_open = 1;
+
+# if defined(__linux) && defined(DEVRANDOM_WAIT) \
+ && defined(OPENSSL_RAND_SEED_GETRANDOM)
+static void *shm_addr;
+
+# if !defined(FIPS_MODULE)
+static void cleanup_shm(void)
+{
+ shmdt(shm_addr);
+}
+# endif
+
+/*
+ * Ensure that the system randomness source has been adequately seeded.
+ * This is done by having the first start of libcrypto, wait until the device
+ * /dev/random becomes able to supply a byte of entropy. Subsequent starts
+ * of the library and later reseedings do not need to do this.
+ */
+static int wait_random_seeded(void)
+{
+ static int seeded = OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID < 0;
+ static const int kernel_version[] = { DEVRANDOM_SAFE_KERNEL };
+ int kernel[2];
+ int shm_id, fd, r;
+ char c, *p;
+ struct utsname un;
+ fd_set fds;
+
+ if (!seeded) {
+ /* See if anything has created the global seeded indication */
+ if ((shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1, 0)) == -1) {
+ /*
+ * Check the kernel's version and fail if it is too recent.
+ *
+ * Linux kernels from 4.8 onwards do not guarantee that
+ * /dev/urandom is properly seeded when /dev/random becomes
+ * readable. However, such kernels support the getentropy(2)
+ * system call and this should always succeed which renders
+ * this alternative but essentially identical source moot.
+ */
+ if (uname(&un) == 0) {
+ kernel[0] = atoi(un.release);
+ p = strchr(un.release, '.');
+ kernel[1] = p == NULL ? 0 : atoi(p + 1);
+ if (kernel[0] > kernel_version[0]
+ || (kernel[0] == kernel_version[0]
+ && kernel[1] >= kernel_version[1])) {
+ return 0;
+ }
+ }
+ /* Open /dev/random and wait for it to be readable */
+ if ((fd = open(DEVRANDOM_WAIT, O_RDONLY)) != -1) {
+ if (DEVRANDM_WAIT_USE_SELECT && fd < FD_SETSIZE) {
+ FD_ZERO(&fds);
+ FD_SET(fd, &fds);
+ while ((r = select(fd + 1, &fds, NULL, NULL, NULL)) < 0
+ && errno == EINTR);
+ } else {
+ while ((r = read(fd, &c, 1)) < 0 && errno == EINTR);
+ }
+ close(fd);
+ if (r == 1) {
+ seeded = 1;
+ /* Create the shared memory indicator */
+ shm_id = shmget(OPENSSL_RAND_SEED_DEVRANDOM_SHM_ID, 1,
+ IPC_CREAT | S_IRUSR | S_IRGRP | S_IROTH);
+ }
+ }
+ }
+ if (shm_id != -1) {
+ seeded = 1;
+ /*
+ * Map the shared memory to prevent its premature destruction.
+ * If this call fails, it isn't a big problem.
+ */
+ shm_addr = shmat(shm_id, NULL, SHM_RDONLY);
+# ifndef FIPS_MODULE
+ /* TODO 3.0: The FIPS provider doesn't have OPENSSL_atexit */
+ if (shm_addr != (void *)-1)
+ OPENSSL_atexit(&cleanup_shm);
+# endif
+ }
+ }
+ return seeded;
+}
+# else /* defined __linux && DEVRANDOM_WAIT && OPENSSL_RAND_SEED_GETRANDOM */
+static int wait_random_seeded(void)
+{
+ return 1;
+}
+# endif
+
+/*
+ * Verify that the file descriptor associated with the random source is
+ * still valid. The rationale for doing this is the fact that it is not
+ * uncommon for daemons to close all open file handles when daemonizing.
+ * So the handle might have been closed or even reused for opening
+ * another file.
+ */
+static int check_random_device(struct random_device * rd)
+{
+ struct stat st;
+
+ return rd->fd != -1
+ && fstat(rd->fd, &st) != -1
+ && rd->dev == st.st_dev
+ && rd->ino == st.st_ino
+ && ((rd->mode ^ st.st_mode) & ~(S_IRWXU | S_IRWXG | S_IRWXO)) == 0
+ && rd->rdev == st.st_rdev;