From 4c139229611631a3497c224a61107b6b6918e3bf Mon Sep 17 00:00:00 2001
From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Sun, 2 Dec 2007 03:27:42 +0000
Subject: Introduce FEATURE_COPYBUF_KB. People who want smaller stack at any
cost may use it to reduce cp's stack usage (FEATURE_COPYBUF_KB=1). Desktop
people may get faster copy of big files (FEATURE_COPYBUF_KB=32 is ~30% faster
than 4kb)
---
libbb/Config.in | 10 ++++++++++
libbb/copyfd.c | 32 ++++++++++++++++++++++++--------
2 files changed, 34 insertions(+), 8 deletions(-)
diff --git a/libbb/Config.in b/libbb/Config.in
index 5055015cf..6bbeffb43 100644
--- a/libbb/Config.in
+++ b/libbb/Config.in
@@ -110,6 +110,16 @@ config FEATURE_EDITING_FANCY_PROMPT
Setting this option allows for prompts to use things like \w and
\$ and escape codes.
+config FEATURE_COPYBUF_KB
+ int "Copy buffer size, in kilobytes"
+ range 1 1024
+ default 4
+ help
+ Size of buffer used by cp, mv, install etc.
+ Buffers which are 4 kb or less will be allocated on stack.
+ Bigger buffers will be allocated with mmap, with fallback to 4 kb
+ stack buffer if mmap fails.
+
config MONOTONIC_SYSCALL
bool "Use clock_gettime(CLOCK_MONOTONIC) syscall"
default y
diff --git a/libbb/copyfd.c b/libbb/copyfd.c
index 3255e424a..ed383ae28 100644
--- a/libbb/copyfd.c
+++ b/libbb/copyfd.c
@@ -9,31 +9,42 @@
#include "libbb.h"
-#if BUFSIZ < 4096
-#undef BUFSIZ
-#define BUFSIZ 4096
-#endif
-
/* Used by NOFORK applets (e.g. cat) - must not use xmalloc */
static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
{
int status = -1;
off_t total = 0;
- char buffer[BUFSIZ];
+#if CONFIG_FEATURE_COPYBUF_KB <= 4
+ char buffer[CONFIG_FEATURE_COPYBUF_KB * 1024];
+ enum { buffer_size = sizeof(buffer) };
+#else
+ char *buffer;
+ int buffer_size;
+
+ buffer = mmap(NULL, CONFIG_FEATURE_COPYBUF_KB * 1024,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANON,
+ /* ignored: */ -1, 0);
+ buffer_size = CONFIG_FEATURE_COPYBUF_KB * 1024;
+ if (buffer == MAP_FAILED) {
+ buffer = alloca(4 * 1024);
+ buffer_size = 4 * 1024;
+ }
+#endif
if (src_fd < 0)
goto out;
if (!size) {
- size = BUFSIZ;
+ size = buffer_size;
status = 1; /* copy until eof */
}
while (1) {
ssize_t rd;
- rd = safe_read(src_fd, buffer, size > BUFSIZ ? BUFSIZ : size);
+ rd = safe_read(src_fd, buffer, size > buffer_size ? buffer_size : size);
if (!rd) { /* eof - all done */
status = 0;
@@ -62,6 +73,11 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
}
}
out:
+
+#if CONFIG_FEATURE_COPYBUF_KB > 4
+ if (buffer_size != 4 * 1024)
+ munmap(buffer, buffer_size);
+#endif
return status ? -1 : total;
}
--
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