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authorNatanael Copa <ncopa@alpinelinux.org>2016-09-08 19:07:31 +0200
committerRich Felker <dalias@aerifal.cx>2016-10-20 01:20:27 -0400
commit05973dc3bbc1aca9b3c8347de6879ed72147ab3b (patch)
treecb2504eebdf2f05acf895cca5cb7076b39da02de /src
parent167dfe9672c116b315e72e57a55c7769f180dffa (diff)
downloadmusl-05973dc3bbc1aca9b3c8347de6879ed72147ab3b.tar.gz
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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>
Diffstat (limited to 'src')
-rw-r--r--src/misc/mntent.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/src/misc/mntent.c b/src/misc/mntent.c
index a16d6525..eabb8200 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;
+static size_t internal_bufsize;
+
+#define SENTINEL (char *)&internal_buf
+
 FILE *setmntent(const char *name, const char *mode)
 {
 	return fopen(name, mode);
@@ -16,13 +21,18 @@ 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 +59,8 @@ 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)