From 666d4aacfd91d8c0447a1e4f8d44d50a3fe40198 Mon Sep 17 00:00:00 2001
Message-Id: <666d4aacfd91d8c0447a1e4f8d44d50a3fe40198@dist-git>
From: Michal Privoznik <mprivozn@redhat.com>
Date: Tue, 23 Oct 2018 11:40:58 +0100
Subject: [PATCH] virfile: Take symlink into account in virFileIsSharedFixFUSE

RHEL-7.7: https://bugzilla.redhat.com/show_bug.cgi?id=1640465
RHEL-7.6.z: https://bugzilla.redhat.com/show_bug.cgi?id=1641798
RHEL-8.0: https://bugzilla.redhat.com/show_bug.cgi?id=1634782

Weirdly enough, there can be symlinks in the path we are trying
to fix. If it is the case our clever algorithm that finds matches
against mount table won't work. Canonicalize path at the
beginning then.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
(cherry picked from commit c0790e3a09f57da0bd25c7eac4a35ed6e7e9e858)
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
---
 cfg.mk              |  2 +-
 src/util/virfile.c  | 15 +++++++++++++--
 tests/virfilemock.c | 33 ++++++++++++++++++++++++++++++++-
 tests/virfiletest.c |  1 +
 4 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/cfg.mk b/cfg.mk
index 6bebd0ad9f..e3e94bf6f0 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -1216,7 +1216,7 @@ exclude_file_name_regexp--sc_prohibit_select = \
 	^cfg\.mk$$
 
 exclude_file_name_regexp--sc_prohibit_canonicalize_file_name = \
-  ^cfg\.mk$$
+  ^(cfg\.mk|tests/virfilemock\.c)$$
 
 exclude_file_name_regexp--sc_prohibit_raw_allocation = \
   ^(docs/hacking\.html\.in|src/util/viralloc\.[ch]|examples/.*|tests/(securityselinuxhelper|(vircgroup|nss)mock|commandhelper)\.c|tools/wireshark/src/packet-libvirt\.c)$$
diff --git a/src/util/virfile.c b/src/util/virfile.c
index e1dee7633a..716b55d770 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -3549,9 +3549,19 @@ virFileIsSharedFixFUSE(const char *path,
     char mntbuf[1024];
     char *mntDir = NULL;
     char *mntType = NULL;
+    char *canonPath = NULL;
     size_t maxMatching = 0;
     int ret = -1;
 
+    if (!(canonPath = virFileCanonicalizePath(path))) {
+        virReportSystemError(errno,
+                             _("unable to canonicalize %s"),
+                             path);
+        return -1;
+    }
+
+    VIR_DEBUG("Path canonicalization: %s->%s", path, canonPath);
+
     if (!(f = setmntent(PROC_MOUNTS, "r"))) {
         virReportSystemError(errno,
                              _("Unable to open %s"),
@@ -3563,7 +3573,7 @@ virFileIsSharedFixFUSE(const char *path,
         const char *p;
         size_t len = strlen(mb.mnt_dir);
 
-        if (!(p = STRSKIP(path, mb.mnt_dir)))
+        if (!(p = STRSKIP(canonPath, mb.mnt_dir)))
             continue;
 
         if (*(p - 1) != '/' && *p != '/' && *p != '\0')
@@ -3581,12 +3591,13 @@ virFileIsSharedFixFUSE(const char *path,
 
     if (STREQ_NULLABLE(mntType, "fuse.glusterfs")) {
         VIR_DEBUG("Found gluster FUSE mountpoint=%s for path=%s. "
-                  "Fixing shared FS type", mntDir, path);
+                  "Fixing shared FS type", mntDir, canonPath);
         *f_type = GFS2_MAGIC;
     }
 
     ret = 0;
  cleanup:
+    VIR_FREE(canonPath);
     VIR_FREE(mntType);
     VIR_FREE(mntDir);
     endmntent(f);
diff --git a/tests/virfilemock.c b/tests/virfilemock.c
index 822c757380..ae5c8d025a 100644
--- a/tests/virfilemock.c
+++ b/tests/virfilemock.c
@@ -28,11 +28,14 @@
 #endif
 
 #include "virmock.h"
+#include "virstring.h"
+#include "viralloc.h"
 
 #define VIR_FROM_THIS VIR_FROM_NONE
 
 static FILE *(*real_setmntent)(const char *filename, const char *type);
 static int (*real_statfs)(const char *path, struct statfs *buf);
+static char *(*real_canonicalize_file_name)(const char *path);
 
 
 static void
@@ -43,6 +46,7 @@ init_syms(void)
 
     VIR_MOCK_REAL_INIT(setmntent);
     VIR_MOCK_REAL_INIT(statfs);
+    VIR_MOCK_REAL_INIT(canonicalize_file_name);
 }
 
 
@@ -94,6 +98,7 @@ statfs_mock(const char *mtab,
     FILE *f;
     struct mntent mb;
     char mntbuf[1024];
+    char *canonPath = NULL;
     int ret = -1;
 
     if (!(f = real_setmntent(mtab, "r"))) {
@@ -101,10 +106,16 @@ statfs_mock(const char *mtab,
         return -1;
     }
 
+    /* We don't need to do this in callers because real statfs(2)
+     * does that for us. However, in mocked implementation we
+     * need to do this. */
+    if (!(canonPath = canonicalize_file_name(path)))
+        return -1;
+
     while (getmntent_r(f, &mb, mntbuf, sizeof(mntbuf))) {
         int ftype;
 
-        if (STRNEQ(mb.mnt_dir, path))
+        if (STRNEQ(mb.mnt_dir, canonPath))
             continue;
 
         if (STREQ(mb.mnt_type, "nfs") ||
@@ -136,6 +147,7 @@ statfs_mock(const char *mtab,
     }
 
     endmntent(f);
+    VIR_FREE(canonPath);
     return ret;
 }
 
@@ -152,3 +164,22 @@ statfs(const char *path, struct statfs *buf)
 
     return real_statfs(path, buf);
 }
+
+
+char *
+canonicalize_file_name(const char *path)
+{
+    if (getenv("LIBVIRT_MTAB")) {
+        const char *p;
+        char *ret;
+
+        if ((p = STRSKIP(path, "/some/symlink")))
+            ignore_value(virAsprintfQuiet(&ret, "/gluster%s", p));
+        else
+            ignore_value(VIR_STRDUP_QUIET(ret, path));
+
+        return ret;
+    }
+
+    return real_canonicalize_file_name(path);
+}
diff --git a/tests/virfiletest.c b/tests/virfiletest.c
index be4dbf8910..a246d601ba 100644
--- a/tests/virfiletest.c
+++ b/tests/virfiletest.c
@@ -457,6 +457,7 @@ mymain(void)
     DO_TEST_FILE_IS_SHARED_FS_TYPE("mounts3.txt", "/nfs/blah", false);
     DO_TEST_FILE_IS_SHARED_FS_TYPE("mounts3.txt", "/gluster/file", true);
     DO_TEST_FILE_IS_SHARED_FS_TYPE("mounts3.txt", "/gluster/sshfs/file", false);
+    DO_TEST_FILE_IS_SHARED_FS_TYPE("mounts3.txt", "/some/symlink/file", true);
 
     return ret != 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 }
-- 
2.19.2