main/musl: fix for getmntent

ref #5703

1 files changed, 66 insertions, 0 deletions

diff --git a/main/musl/0001-use-dynamic-buffer-for-getmntent.patch b/main/musl/0001-use-dynamic-buffer-for-getmntent.patch
new file mode 100644
index 0000000000..12feaa8266
--- /dev/null
+++ b/main/musl/0001-use-dynamic-buffer-for-getmntent.patch
@@ -0,0 +1,66 @@
+From c0dd2db34a8a5d51699406a90a4f87cb3129d5a1 Mon Sep 17 00:00:00 2001
+From: Natanael Copa <ncopa@alpinelinux.org>
+Date: Thu, 8 Sep 2016 09:06:22 +0200
+Subject: [PATCH] use dynamic buffer for getmntent
+
+overlayfs may have fairly long lines so we use getline to allocate a
+buffer dynamically. The buffer will be allocated on first use, expand as
+needed, but will never be free'ed.
+
+Downstream bug: http://bugs.alpinelinux.org/issues/5703
+
+Signed-off-by: Natanael Copa <ncopa@alpinelinux.org>
+---
+ src/misc/mntent.c | 16 ++++++++++++----
+ 1 file changed, 12 insertions(+), 4 deletions(-)
+
+diff --git a/src/misc/mntent.c b/src/misc/mntent.c
+index a16d652..722a030 100644
+--- a/src/misc/mntent.c
++++ b/src/misc/mntent.c
+@@ -3,6 +3,11 @@
+ #include <mntent.h>
+ #include <errno.h>
+ 
++static char *internal_buf = NULL;
++static size_t internal_bufsize = 0;
++
++#define SENTINEL (char *)&internal_buf
++
+ FILE *setmntent(const char *name, const char *mode)
+ {
+ 	return fopen(name, mode);
+@@ -16,13 +21,17 @@ int endmntent(FILE *f)
+ 
+ struct mntent *getmntent_r(FILE *f, struct mntent *mnt, char *linebuf, int buflen)
+ {
+-	int cnt, n[8];
++	int cnt, n[8], use_internal = (linebuf == SENTINEL);
+ 
+ 	mnt->mnt_freq = 0;
+ 	mnt->mnt_passno = 0;
+ 
+ 	do {
+-		fgets(linebuf, buflen, f);
++		if (use_internal) {
++			getline(&internal_buf, &internal_bufsize, f);
++			linebuf = internal_buf;
++		} else
++			fgets(linebuf, buflen, f);
+ 		if (feof(f) || ferror(f)) return 0;
+ 		if (!strchr(linebuf, '\n')) {
+ 			fscanf(f, "%*[^\n]%*[\n]");
+@@ -49,9 +58,8 @@ struct mntent *getmntent_r(FILE *f, struct mntent *mnt, char *linebuf, int bufle
+ 
+ struct mntent *getmntent(FILE *f)
+ {
+-	static char linebuf[256];
+ 	static struct mntent mnt;
+-	return getmntent_r(f, &mnt, linebuf, sizeof linebuf);
++	return getmntent_r(f, &mnt, SENTINEL, 0);
+ }
+ 
+ int addmntent(FILE *f, const struct mntent *mnt)
+-- 
+2.10.0
+