X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=libbb%2Fcopyfd.c;h=921fe3f81005d35063c8fb801cb54a75901586b8;hb=6b0695bb66dd38af4d4671fb2381fa3e1dbfe90c;hp=0976180afd8ab2b45a6625d2dc219607754d5267;hpb=7600eec7325f0bbce1dcbf08e76c1653bf35b397;p=oweals%2Fbusybox.git

diff --git a/libbb/copyfd.c b/libbb/copyfd.c
index 0976180af..921fe3f81 100644
--- a/libbb/copyfd.c
+++ b/libbb/copyfd.c
@@ -4,72 +4,160 @@
  *
  * Copyright (C) 1999-2005 by Erik Andersen <andersen@codepoet.org>
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 
-#include <errno.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-#include "busybox.h"
 #include "libbb.h"
-
-
-#if BUFSIZ < 4096
-#undef BUFSIZ
-#define BUFSIZ 4096
+#if ENABLE_FEATURE_USE_SENDFILE
+# include <sys/sendfile.h>
+#else
+# define sendfile(a,b,c,d) (-1)
 #endif
 
+/*
+ * We were using 0x7fff0000 as sendfile chunk size, but it
+ * was seen to cause largish delays when user tries to ^C a file copy.
+ * Let's use a saner size.
+ * Note: needs to be >= max(CONFIG_FEATURE_COPYBUF_KB),
+ * or else "copy to eof" code will use neddlesly short reads.
+ */
+#define SENDFILE_BIGBUF (16*1024*1024)
 
-static ssize_t bb_full_fd_action(int src_fd, int dst_fd, size_t size)
+/* Used by NOFORK applets (e.g. cat) - must not use xmalloc.
+ * size < 0 means "ignore write errors", used by tar --to-command
+ * size = 0 means "copy till EOF"
+ */
+static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
 {
 	int status = -1;
-	size_t total = 0;
-	RESERVE_CONFIG_BUFFER(buffer,BUFSIZ);
+	off_t total = 0;
+	bool continue_on_write_error = 0;
+	ssize_t sendfile_sz;
+#if CONFIG_FEATURE_COPYBUF_KB > 4
+	char *buffer = buffer; /* for compiler */
+	int buffer_size = 0;
+#else
+	char buffer[CONFIG_FEATURE_COPYBUF_KB * 1024];
+	enum { buffer_size = sizeof(buffer) };
+#endif
 
-	if (src_fd < 0) goto out;
-	while (!size || total < size)
-	{
-		ssize_t wrote, xread;
+	if (size < 0) {
+		size = -size;
+		continue_on_write_error = 1;
+	}
 
-		xread = safe_read(src_fd, buffer,
-				(!size || size - total > BUFSIZ) ? BUFSIZ : size - total);
+	if (src_fd < 0)
+		goto out;
 
-		if (xread > 0) {
-			/* A -1 dst_fd means we need to fake it... */
-			wrote = (dst_fd < 0) ? xread : bb_full_write(dst_fd, buffer, xread);
-			if (wrote < xread) {
-				bb_perror_msg(bb_msg_write_error);
-				break;
+	sendfile_sz = !ENABLE_FEATURE_USE_SENDFILE
+		? 0
+		: SENDFILE_BIGBUF;
+	if (!size) {
+		size = SENDFILE_BIGBUF;
+		status = 1; /* copy until eof */
+	}
+
+	while (1) {
+		ssize_t rd;
+
+		if (sendfile_sz) {
+			rd = sendfile(dst_fd, src_fd, NULL,
+				size > sendfile_sz ? sendfile_sz : size);
+			if (rd >= 0)
+				goto read_ok;
+			sendfile_sz = 0; /* do not try sendfile anymore */
+		}
+#if CONFIG_FEATURE_COPYBUF_KB > 4
+		if (buffer_size == 0) {
+			if (size > 0 && size <= 4 * 1024)
+				goto use_small_buf;
+			/* We want page-aligned buffer, just in case kernel is clever
+			 * and can do page-aligned io more efficiently */
+			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) {
+ use_small_buf:
+				buffer = alloca(4 * 1024);
+				buffer_size = 4 * 1024;
 			}
-			total += wrote;
-		} else if (xread < 0) {
+		}
+#endif
+		rd = safe_read(src_fd, buffer,
+			size > buffer_size ? buffer_size : size);
+		if (rd < 0) {
 			bb_perror_msg(bb_msg_read_error);
 			break;
-		} else if (xread == 0) {
-			/* All done. */
+		}
+ read_ok:
+		if (!rd) { /* eof - all done */
 			status = 0;
 			break;
 		}
+		/* dst_fd == -1 is a fake, else... */
+		if (dst_fd >= 0 && !sendfile_sz) {
+			ssize_t wr = full_write(dst_fd, buffer, rd);
+			if (wr < rd) {
+				if (!continue_on_write_error) {
+					bb_perror_msg(bb_msg_write_error);
+					break;
+				}
+				dst_fd = -1;
+			}
+		}
+		total += rd;
+		if (status < 0) { /* if we aren't copying till EOF... */
+			size -= rd;
+			if (!size) {
+				/* 'size' bytes copied - all done */
+				status = 0;
+				break;
+			}
+		}
 	}
+ out:
 
-out:
-	RELEASE_CONFIG_BUFFER(buffer);
-
-	return status ? status : (ssize_t)total;
+/* some environments don't have munmap(), hide it in #if */
+#if CONFIG_FEATURE_COPYBUF_KB > 4
+	if (buffer_size > 4 * 1024)
+		munmap(buffer, buffer_size);
+#endif
+	return status ? -1 : total;
 }
 
 
-extern int bb_copyfd_size(int fd1, int fd2, const off_t size)
+#if 0
+void FAST_FUNC complain_copyfd_and_die(off_t sz)
+{
+	if (sz != -1)
+		bb_error_msg_and_die("short read");
+	/* if sz == -1, bb_copyfd_XX already complained */
+	xfunc_die();
+}
+#endif
+
+off_t FAST_FUNC bb_copyfd_size(int fd1, int fd2, off_t size)
 {
 	if (size) {
-		return(bb_full_fd_action(fd1, fd2, size));
+		return bb_full_fd_action(fd1, fd2, size);
 	}
-	return(0);
+	return 0;
+}
+
+void FAST_FUNC bb_copyfd_exact_size(int fd1, int fd2, off_t size)
+{
+	off_t sz = bb_copyfd_size(fd1, fd2, size);
+	if (sz == (size >= 0 ? size : -size))
+		return;
+	if (sz != -1)
+		bb_error_msg_and_die("short read");
+	/* if sz == -1, bb_copyfd_XX already complained */
+	xfunc_die();
 }
 
-extern int bb_copyfd_eof(int fd1, int fd2)
+off_t FAST_FUNC bb_copyfd_eof(int fd1, int fd2)
 {
-	return(bb_full_fd_action(fd1, fd2, 0));
+	return bb_full_fd_action(fd1, fd2, 0);
 }