From 98a4bd2b9fa6f4f74265d6b645edefc91ad57a48 Mon Sep 17 00:00:00 2001
From: hippoz <10706925-hippoz@users.noreply.gitlab.com>
Date: Tue, 17 Jan 2023 23:04:48 +0200
Subject: [PATCH] don't open urandom for hello

---
 server.c | 45 ++++++++++++++++++++++++++++++---------------
 server.h |  1 +
 2 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/server.c b/server.c
index 0cc5e28..880ab3c 100644
--- a/server.c
+++ b/server.c
@@ -33,7 +33,8 @@ uint64_t hashmap_hash(const char *bytes, size_t bytes_n, size_t map_len)
 void bus_free(bus_t *s)
 {
     if (!s) return;
-    if (s->sock_fd) close(s->sock_fd);
+    if (s->sock_fd >= 0) close(s->sock_fd);
+    if (s->urandom_fd >= 0) close(s->urandom_fd);
     // freeing all clients will also free all matches and names
     for (int i = 0; i < BUS_MAX_CLIENTS; i++) {
         bus_client_remove(s, i);
@@ -48,10 +49,17 @@ bus_t *bus_create(const char *socket_path)
         return NULL;
     }
 
+    s->urandom_fd = -1;
+    s->sock_fd = -1;
+
+    s->urandom_fd = open("/dev/urandom", 0);
+    if (s->urandom_fd < 0) {
+        goto defer_fail;
+    }
+
     s->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
     if (s->sock_fd == -1) {
-        free(s);
-        return NULL;
+        goto defer_fail;
     }
 
     struct sockaddr_un name;
@@ -61,15 +69,19 @@ bus_t *bus_create(const char *socket_path)
 
     unlink(socket_path);
 
+    int flags = fcntl(s->sock_fd, F_GETFL, 0);
+    if (flags < 0) {
+        goto defer_fail;
+    }
+    if (fcntl(s->sock_fd, F_SETFL, flags | O_NONBLOCK) < 0) {
+        goto defer_fail;
+    }
+
     if (bind(s->sock_fd, (const struct sockaddr *)&name, sizeof(name)) == -1) {
-        close(s->sock_fd);
-        free(s);
-        return NULL;
+        goto defer_fail;
     }
     if (listen(s->sock_fd, BUS_BACKLOG) == -1) {
-        close(s->sock_fd);
-        free(s);
-        return NULL;
+        goto defer_fail;
     }
 
     for (int i = 0; i < BUS_MAX_CLIENTS; i++) {
@@ -100,6 +112,13 @@ bus_t *bus_create(const char *socket_path)
     s->fd_num = BUS_MAX_CLIENTS + 1;
 
     return s;
+defer_fail:
+    if (s) {
+        if (s->urandom_fd >= 0) close(s->urandom_fd);
+        if (s->sock_fd >= 0) close(s->sock_fd);
+        free(s);
+    }
+    return NULL;
 }
 
 int bus_client_add(bus_t *s, int fd)
@@ -198,14 +217,10 @@ int bus_client_assign_unique_name(bus_t *s, int i)
         return -1;
     }
     uint32_t id = 0;
-    FILE *urandom_file = fopen("/dev/urandom", "rb");
-    if (!urandom_file) {
+
+    if (read(s->urandom_fd, &id, sizeof(uint32_t)) != sizeof(uint32_t)) {
         return -1;
     }
-    if (fread(&id, 1, sizeof(uint32_t), urandom_file) != sizeof(uint32_t)) {
-        return -1;
-    }
-    fclose(urandom_file);
 
     char *name = malloc(sizeof(char) * 16);
     if (!name) {
diff --git a/server.h b/server.h
index 3d45b21..cae57f1 100644
--- a/server.h
+++ b/server.h
@@ -49,6 +49,7 @@ typedef struct bus {
     int fd_num;
     int names_count;
     int clients_count;
+    int urandom_fd;
     bus_client_t clients[BUS_MAX_CLIENTS];
     bus_name_t names[BUS_MAX_NAMES];
     struct pollfd fds[BUS_MAX_CLIENTS + 1];