From d3cef27b10ec91b14c917f52ff0d4550d81327f6 Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Thu, 19 Oct 2023 12:51:38 -0500
Subject: [PATCH] Switch yes to writev() a redundant iovec to produce output in
 bigger chunks, speeding it up from megabytes to gigabytes.

Also, move #include uio.h from dd.c to toys.h (it's posix, and has a second
user now), and fnmatch.h moved into portability.h for horrible glibc
sequencing reasons so remove second NOP #include of the same header.
---
 toys.h           |  2 +-
 toys/other/yes.c | 34 +++++++++++++++++++++++++---------
 toys/posix/dd.c  |  1 -
 3 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/toys.h b/toys.h
index 49b02ffb..bde3d90d 100644
--- a/toys.h
+++ b/toys.h
@@ -13,7 +13,6 @@
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
-#include <fnmatch.h>
 #include <grp.h>
 #include <inttypes.h>
 #include <limits.h>
@@ -37,6 +36,7 @@
 #include <sys/statvfs.h>
 #include <sys/time.h>
 #include <sys/times.h>
+#include <sys/uio.h>
 #include <sys/utsname.h>
 #include <sys/wait.h>
 #include <syslog.h>
diff --git a/toys/other/yes.c b/toys/other/yes.c
index 8edba0ae..6e7887ee 100644
--- a/toys/other/yes.c
+++ b/toys/other/yes.c
@@ -2,7 +2,7 @@
  *
  * Copyright 2007 Rob Landley <rob@landley.net>
 
-USE_YES(NEWTOY(yes, NULL, TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_LINEBUF))
+USE_YES(NEWTOY(yes, 0, TOYFLAG_USR|TOYFLAG_BIN))
 
 config YES
   bool "yes"
@@ -17,13 +17,29 @@ config YES
 
 void yes_main(void)
 {
-  for (;;) {
-    int i;
-    for (i=0; toys.optargs[i]; i++) {
-      if (i) xputc(' ');
-      xprintf("%s", toys.optargs[i]);
-    }
-    if (!i) xputc('y');
-    xputc('\n');
+  struct iovec *iov = (void *)toybuf;
+  char *out, *ss;
+  long len, ll, i, j;
+
+  // Collate command line arguments into one string, or repeated "y\n".
+  for (len = i = 0; toys.optargs[i]; i++) len += strlen(toys.optargs[i]) + 1;
+  ss = out = xmalloc(len ? : 128);
+  if (!i) for (i = 0; i<64; i++) {
+    *ss++ = 'y';
+    *ss++ = '\n';
+  } else {
+    for (i = 0; toys.optargs[i]; i++)
+      ss += sprintf(ss, " %s"+!i, toys.optargs[i]);
+    *ss++ = '\n';
+  }
+
+  // Populate a redundant iovec[] outputting the same string many times
+  for (i = ll = 0; i<sizeof(toybuf)/sizeof(*iov); i++) {
+    iov[i].iov_base = out;
+    ll += (iov[i].iov_len = ss-out);
   }
+
+  // Writev the output until stdout stops accepting it
+  for (;;) for (len = 0; len<ll; len += j)
+    if (0>(j = writev(1, iov, i))) perror_exit(0);
 }
diff --git a/toys/posix/dd.c b/toys/posix/dd.c
index 4c9670e7..7fc721fc 100644
--- a/toys/posix/dd.c
+++ b/toys/posix/dd.c
@@ -40,7 +40,6 @@ config DD
 
 #define FOR_dd
 #include "toys.h"
-#include <sys/uio.h>
 
 GLOBALS(
   // Display fields
-- 
2.39.2