From 27b5b58381dfebb32315f78410694ba6b6551b8e Mon Sep 17 00:00:00 2001 From: Yann Sionneau Date: Mon, 19 Oct 2020 08:09:54 +0200 Subject: hasmntopt: better option matching Previous implementation was respecting the man page description of what the function should do. Also the function does not seem to be defined by POSIX. But... to be really useful the function needs to handle option matching and not just substring matching. This is copy pasted from glibc. This fixes issue reported by https://github.com/wbx-github/uclibc-ng/issues/8 that can happen for instance there: https://github.com/frida/glib/blob/master/gio/gunixmounts.c#L622 Signed-off-by: Yann Sionneau --- libc/misc/mntent/mntent.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'libc') diff --git a/libc/misc/mntent/mntent.c b/libc/misc/mntent/mntent.c index 608f84c1a..610e35af6 100644 --- a/libc/misc/mntent/mntent.c +++ b/libc/misc/mntent/mntent.c @@ -1,5 +1,6 @@ /* * Copyright (C) 2000-2006 Erik Andersen + * Copyright (C) 1995-2020 Free Software Foundation, Inc. * * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball. */ @@ -92,9 +93,25 @@ int addmntent(FILE * filep, const struct mntent *mnt) mnt->mnt_type, mnt->mnt_opts, mnt->mnt_freq, mnt->mnt_passno) < 0 ? 1 : 0); } -char *hasmntopt(const struct mntent *mnt, const char *opt) +/* Search MNT->mnt_opts for an option matching OPT. + Returns the address of the substring, or null if none found. */ +char *hasmntopt (const struct mntent *mnt, const char *opt) { - return strstr(mnt->mnt_opts, opt); + const size_t optlen = strlen(opt); + char *rest = mnt->mnt_opts, *p; + + while ((p = strstr(rest, opt)) != NULL) { + if ((p == rest || p[-1] == ',') + && (p[optlen] == '\0' || p[optlen] == '=' || p[optlen] == ',')) + return p; + + rest = strchr(p, ','); + if (rest == NULL) + break; + ++rest; + } + + return NULL; } FILE *setmntent(const char *name, const char *mode) -- cgit v1.2.3