eal: add getline() function for Windows

Message ID 1746477607-14961-1-git-send-email-andremue@linux.microsoft.com (mailing list archive)
State New
Delegated to: Thomas Monjalon
Headers
Series eal: add getline() function for Windows |

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Commit Message

Andre Muezerie May 5, 2025, 8:40 p.m. UTC
Existing DPDK code uses getline(), which is a POSIX function and is
not available in the Windows APIs.

Instead of rewriting it or coming up with some other replacement, this
patch makes use of the implementation provided by NetBSD to make it
possible to compile code dependent on getline on Windows.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 lib/eal/windows/getline.c         | 61 +++++++++++++++++++++++++++++++
 lib/eal/windows/include/getline.h | 28 ++++++++++++++
 lib/eal/windows/meson.build       |  1 +
 license/exceptions.txt            |  2 +
 4 files changed, 92 insertions(+)
 create mode 100644 lib/eal/windows/getline.c
 create mode 100644 lib/eal/windows/include/getline.h
  

Comments

Stephen Hemminger May 20, 2025, 5:14 p.m. UTC | #1
On Mon,  5 May 2025 13:40:07 -0700
Andre Muezerie <andremue@linux.microsoft.com> wrote:

> Existing DPDK code uses getline(), which is a POSIX function and is
> not available in the Windows APIs.
> 
> Instead of rewriting it or coming up with some other replacement, this
> patch makes use of the implementation provided by NetBSD to make it
> possible to compile code dependent on getline on Windows.
> 
> Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>

Not sure, are BSD-2 and BSD-3 compatible?
Getting license exception approved requires going through the governing board
which can take up to 6 months.
  
Andre Muezerie May 21, 2025, 12:35 a.m. UTC | #2
On Tue, May 20, 2025 at 10:14:33AM -0700, Stephen Hemminger wrote:
> On Mon,  5 May 2025 13:40:07 -0700
> Andre Muezerie <andremue@linux.microsoft.com> wrote:
> 
> > Existing DPDK code uses getline(), which is a POSIX function and is
> > not available in the Windows APIs.
> > 
> > Instead of rewriting it or coming up with some other replacement, this
> > patch makes use of the implementation provided by NetBSD to make it
> > possible to compile code dependent on getline on Windows.
> > 
> > Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
> 
> Not sure, are BSD-2 and BSD-3 compatible?
> Getting license exception approved requires going through the governing board
> which can take up to 6 months.

Hi Stephen, I would appreciate some guidance here.

My understanding is that in general, BSD-2 licensed code can be used in BSD-3
licensed projects, as long as the BSD-2 license is retained in the original
 (BSD-2) files.

I do see that BSD-2 was listed in the exception table (for getopt function). It's
not clear to me why it needed to be listed as an exception, but if that was
needed, it indicates that the same should be done for getline(). Is that not
the case?
  
Thomas Monjalon May 21, 2025, 7 a.m. UTC | #3
21/05/2025 02:35, Andre Muezerie:
> On Tue, May 20, 2025 at 10:14:33AM -0700, Stephen Hemminger wrote:
> > On Mon,  5 May 2025 13:40:07 -0700
> > Andre Muezerie <andremue@linux.microsoft.com> wrote:
> > 
> > > Existing DPDK code uses getline(), which is a POSIX function and is
> > > not available in the Windows APIs.
> > > 
> > > Instead of rewriting it or coming up with some other replacement, this
> > > patch makes use of the implementation provided by NetBSD to make it
> > > possible to compile code dependent on getline on Windows.
> > > 
> > > Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
> > 
> > Not sure, are BSD-2 and BSD-3 compatible?
> > Getting license exception approved requires going through the governing board
> > which can take up to 6 months.
> 
> Hi Stephen, I would appreciate some guidance here.
> 
> My understanding is that in general, BSD-2 licensed code can be used in BSD-3
> licensed projects, as long as the BSD-2 license is retained in the original
>  (BSD-2) files.
> 
> I do see that BSD-2 was listed in the exception table (for getopt function). It's
> not clear to me why it needed to be listed as an exception, but if that was
> needed, it indicates that the same should be done for getline(). Is that not
> the case?

No matter the compatibility agreed or not in courts,
if the licence is different we note it as an exception,
so it is crystal clear for users of DPDK.
We don't want to have any surprise and we avoid exceptions,
that's why the Governing Board has to accept it.
  

Patch

diff --git a/lib/eal/windows/getline.c b/lib/eal/windows/getline.c
new file mode 100644
index 0000000000..955452b50e
--- /dev/null
+++ b/lib/eal/windows/getline.c
@@ -0,0 +1,61 @@ 
+/* SPDX-License-Identifier: BSD-2-Clause
+ * Copyright (c) 2011 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Christos Zoulas.
+ */
+
+#include <malloc.h>
+
+#include "getline.h"
+
+ssize_t
+getdelim(char **buf, size_t *bufsiz, int delimiter, FILE *fp)
+{
+	char *ptr, *eptr;
+
+	if (*buf == NULL || *bufsiz == 0) {
+		*bufsiz = BUFSIZ;
+		*buf = malloc(*bufsiz);
+		if (buf == NULL)
+			return -1;
+	}
+
+	for (ptr = *buf, eptr = *buf + *bufsiz;;) {
+		int c = fgetc(fp);
+		if (c == -1) {
+			if (feof(fp)) {
+				ssize_t diff = (ssize_t)(ptr - *buf);
+				if (diff != 0) {
+					*ptr = '\0';
+					return diff;
+				}
+			}
+			return -1;
+		}
+		*ptr++ = c;
+		if (c == delimiter) {
+			*ptr = '\0';
+			return ptr - *buf;
+		}
+		if (ptr + 2 >= eptr) {
+			char *nbuf;
+			size_t nbufsiz = *bufsiz * 2;
+			ssize_t d = ptr - *buf;
+			nbuf = realloc(*buf, nbufsiz);
+			if (nbuf == NULL)
+				return -1;
+			*buf = nbuf;
+			*bufsiz = nbufsiz;
+			eptr = nbuf + nbufsiz;
+			ptr = nbuf + d;
+		}
+	}
+}
+
+ssize_t
+getline(char **buf, size_t *bufsiz, FILE *fp)
+{
+	return getdelim(buf, bufsiz, '\n', fp);
+}
diff --git a/lib/eal/windows/include/getline.h b/lib/eal/windows/include/getline.h
new file mode 100644
index 0000000000..2931ce2a02
--- /dev/null
+++ b/lib/eal/windows/include/getline.h
@@ -0,0 +1,28 @@ 
+/* SPDX-License-Identifier: BSD-2-Clause
+ * Copyright (c) 2011 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Christos Zoulas.
+ */
+
+/**
+ * @file
+ * getline compat.
+ *
+ * This module provides getline() and getdelim().
+ */
+
+#pragma once
+
+#include <stdio.h>
+
+#ifndef ssize_t
+#define ssize_t ptrdiff_t
+#endif
+
+ssize_t
+getdelim(char **buf, size_t *bufsiz, int delimiter, FILE *fp);
+
+ssize_t
+getline(char **buf, size_t *bufsiz, FILE *fp);
diff --git a/lib/eal/windows/meson.build b/lib/eal/windows/meson.build
index 7756d417be..c526ede405 100644
--- a/lib/eal/windows/meson.build
+++ b/lib/eal/windows/meson.build
@@ -17,6 +17,7 @@  sources += files(
         'eal_mp.c',
         'eal_thread.c',
         'eal_timer.c',
+        'getline.c',
         'getopt.c',
         'rte_thread.c',
 )
diff --git a/license/exceptions.txt b/license/exceptions.txt
index d12fac2034..2785a4f335 100644
--- a/license/exceptions.txt
+++ b/license/exceptions.txt
@@ -16,4 +16,6 @@  MIT                  | 10/23/2019       | 02/10/2020       | lib/eal/windows/inc
 BSD-2-Clause         | 10/23/2019       | 12/18/2019       | lib/eal/windows/include/getopt.h
 ISC AND BSD-2-Clause | 10/23/2019       | 12/18/2019       | lib/eal/windows/getopt.c
 MIT                  | 10/19/2022       | 10/18/2022       | drivers/net/gve/base/*
+BSD-2-Clause         | XX/XX/XXXX       | XX/XX/XXXX       | lib/eal/windows/include/getline.h
+BSD-2-Clause         | XX/XX/XXXX       | XX/XX/XXXX       | lib/eal/windows/getline.c
 ---------------------------------------------------------------------------------------------------