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Date: Thu, 8 Sep 2016 19:07:31 +0200
From: Natanael Copa <ncopa@...inelinux.org>
To: musl@...ts.openwall.com
Cc: Natanael Copa <ncopa@...inelinux.org>
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@...inelinux.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
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