From 317b8e71a5f6d5a50fd3551bff14c03e79798a93 Mon Sep 17 00:00:00 2001
From: Guilherme Janczak <guilherme.janczak@yandex.com>
Date: Tue, 30 Jan 2024 07:56:03 +0000
Subject: [PATCH] Delete old /dev/urandom backend for arc4random

HaikuOS doesn't need it anymore.
---
 docs/CHANGELOG.md                       |  4 +-
 docs/CONTRIBUTING.md                    |  5 +--
 src/stdlib/arc4random_buf_dev_urandom.c | 59 -------------------------
 src/stdlib/meson.build                  | 40 +++++++----------
 4 files changed, 20 insertions(+), 88 deletions(-)
 delete mode 100644 src/stdlib/arc4random_buf_dev_urandom.c

diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 768ecfe..a8b1a0b 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -18,6 +18,8 @@ Changes in libobsd master:
 - Add closefrom()
 - Include io.h in unistd.h on Windows to expose io.h's POSIX functions
 - Add C++ support
-- add timespeccmp(), timespecsub(), and other timeval/timespec macros from
+- Add timespeccmp(), timespecsub(), and other timeval/timespec macros from
   sys/time.h
+- Delete old /dev/urandom backend for arc4random now that HaikuOS doesn't need
+  it anymore
 
diff --git a/docs/CONTRIBUTING.md b/docs/CONTRIBUTING.md
index f6c4f12..02a0977 100644
--- a/docs/CONTRIBUTING.md
+++ b/docs/CONTRIBUTING.md
@@ -1,5 +1,5 @@
 <!--
-Copyright (c) 2022-2023 Guilherme Janczak <guilherme.janczak@yandex.com>
+Copyright (c) 2022-2024 Guilherme Janczak <guilherme.janczak@yandex.com>
 
 Permission to use, copy, modify, and distribute this software for any
 purpose with or without fee is hereby granted, provided that the above
@@ -39,8 +39,7 @@ Every subdirectory under *src/* is named after a header. *stdlib/* for
 subdirectory belong to that header. Instead of piling up `#ifdef`s, I've chosen
 to split each "backend" that implements a function into its own file.
 
-Feature detection is used unless something is impossible to detect. For
-instance, there is some manual checking for Haiku.
+Feature detection is used unless something is impossible to detect.
 
 I don't intend to implement deprecated functions like `rindex()`, or silly
 functions like `getbsize()`. I trust the underlying platform, if it is buggy, fix
diff --git a/src/stdlib/arc4random_buf_dev_urandom.c b/src/stdlib/arc4random_buf_dev_urandom.c
deleted file mode 100644
index 4454f41..0000000
--- a/src/stdlib/arc4random_buf_dev_urandom.c
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Copyright (c) 2022 Guilherme Janczak <guilherme.janczak@yandex.com>
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-
-#include <errno.h>
-#include <fcntl.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-/* Haiku doesn't have a proper programming API for generating random numbers, so
- * it's impossible to provide the semantics of arc4random_buf(). We'll
- * approximate them with /dev/urandom.
- */
-void
-arc4random_buf(void *_buf, size_t nbytes)
-{
-	int errnum;
-	int fd;
-	unsigned char *buf = _buf;
-	ssize_t nr;
-	size_t unr;
-	errnum = errno;
-
-	while ((fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC)) == -1) {
-		if (errno == EINTR)
-			continue;
-		abort();
-	}
-
-	while (nbytes > 0) {
-		nr = read(fd, buf, nbytes);
-		if (nr == -1) {
-			if (errno == EINTR)
-				continue;
-			abort();
-		} else if (nr == 0) {
-			abort(); /* /dev/urandom should never EOF. */
-		}
-
-		unr = nr;
-		buf += unr;
-		nbytes -= unr;
-	}
-
-	close(fd);
-	errno = errnum;
-}
diff --git a/src/stdlib/meson.build b/src/stdlib/meson.build
index a180531..e467985 100644
--- a/src/stdlib/meson.build
+++ b/src/stdlib/meson.build
@@ -1,4 +1,4 @@
-# Copyright (c) 2022 Guilherme Janczak <guilherme.janczak@yandex.com>
+# Copyright (c) 2022, 2024 Guilherme Janczak <guilherme.janczak@yandex.com>
 #
 # Permission to use, copy, modify, and distribute this software for any
 # purpose with or without fee is hereby granted, provided that the above
@@ -39,33 +39,23 @@ foreach func, info : stdlib
 endforeach
 
 if stdlib['arc4random_buf'][2]
-  arc4random_backends = {
-    'getrandom': ['arc4random_buf_getrandom.c', '#include <sys/random.h>'],
-    'BCryptGenRandom': ['arc4random_buf_BCryptGenRandom.c',
-                        '''#include <windows.h>
-                        #include <bcrypt.h>'''],
-
-  }
-
-  if host_machine.system() == 'emscripten'
-    stdlib += {'arc4random_buf': ['arc4random_buf_emscripten.c',
-                                  'arc4random.3', true]}
-  elif host_machine.system() == 'haiku'
-    stdlib += {'arc4random_buf': ['arc4random_buf_dev_urandom.c',
-                                  'arc4random.3', true]}
-  endif
-
   bcrypt_dep = cc.find_library('bcrypt', required: false)
-  if bcrypt_dep.found()
+  bcrypt_pref = '''#include <windows.h>\n#include <bcrypt.h>'''
+  impl = ''
+  if bcrypt_dep.found() and cc.has_function('BCryptGenRandom',
+                                           prefix: bcrypt_pref,
+                                           dependencies: bcrypt_dep)
     deps += bcrypt_dep
+    impl = 'arc4random_buf_BCryptGenRandom.c'
+  elif host_machine.system() == 'emscripten'
+    impl = 'arc4random_buf_emscripten.c'
+  elif cc.has_function('getrandom', args: args,
+                       prefix: '#include <sys/random.h>')
+    impl = 'arc4random_buf_getrandom.c'
+  endif
+  if impl != ''
+    stdlib += {'arc4random_buf': [impl, 'arc4random.3', true]}
   endif
-  foreach func, info : arc4random_backends
-    if cc.has_function(func, args: args, prefix: info[1],
-                       dependencies: deps)
-      stdlib += {'arc4random_buf': [info[0], 'arc4random.3', true]}
-      break
-    endif
-  endforeach
 endif
 
 stdlib_pragma = [] # daemon() needs stdlib_pragma early