From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/10428 Path: news.gmane.org!.POSTED!not-for-mail From: Natanael Copa Newsgroups: gmane.linux.lib.musl.general Subject: [PATCH] use dynamic buffer for getmntent Date: Thu, 8 Sep 2016 19:07:31 +0200 Message-ID: <20160908170731.30407-1-ncopa@alpinelinux.org> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1473354484 8307 195.159.176.226 (8 Sep 2016 17:08:04 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 8 Sep 2016 17:08:04 +0000 (UTC) Cc: Natanael Copa To: musl@lists.openwall.com Original-X-From: musl-return-10441-gllmg-musl=m.gmane.org@lists.openwall.com Thu Sep 08 19:08:00 2016 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1bi2nt-0001Rh-UY for gllmg-musl@m.gmane.org; Thu, 08 Sep 2016 19:07:58 +0200 Original-Received: (qmail 13918 invoked by uid 550); 8 Sep 2016 17:07:56 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 13880 invoked from network); 8 Sep 2016 17:07:51 -0000 X-Mailer: git-send-email 2.10.0 Xref: news.gmane.org gmane.linux.lib.musl.general:10428 Archived-At: 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 --- 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 #include +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