[PATCH] storage: Add support to set{uid,gid} and sticky bit

[Julio Faracco <jcfaracco@xxxxxxxxx>]

This commit add more features to storages that supports setuid, setgid
and sticky bit. This extend some permission levels of volumes when you
run an hypervisor using a specific user that can run but cannot delete
volumes for instance. Additionally, when you create a directory without
`pool-build` command, you cannot import those extra permissions.
Example:

    # mkdir /var/lib/libvirt/images/
    # chmod 0755 /var/lib/libvirt/images/
    # chmod u+s /var/lib/libvirt/images/
    # pool-start default
    # pool-dumpxml default

No setuid from `<mode>0755</mode>`.
Output should expect `<mode>4755</mode>`.

Signed-off-by: Julio Faracco <jcfaracco@xxxxxxxxx>
---
 src/conf/storage_conf.c    | 11 ++++++++---
 src/storage/storage_util.c | 12 ++++++++----
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/conf/storage_conf.c b/src/conf/storage_conf.c
index 252d28cbfb..54e4a60ded 100644
--- a/src/conf/storage_conf.c
+++ b/src/conf/storage_conf.c
@@ -746,7 +746,7 @@ virStorageDefParsePerms(xmlXPathContextPtr ctxt,
     if ((mode = virXPathString("string(./mode)", ctxt))) {
         int tmp;
 
-        if (virStrToLong_i(mode, NULL, 8, &tmp) < 0 || (tmp & ~0777)) {
+        if (virStrToLong_i(mode, NULL, 8, &tmp) < 0 || (tmp & ~07777)) {
             virReportError(VIR_ERR_XML_ERROR, "%s",
                            _("malformed octal mode"));
             goto error;
@@ -1187,9 +1187,14 @@ virStoragePoolDefFormatBuf(virBufferPtr buf,
             def->target.perms.label) {
             virBufferAddLit(buf, "<permissions>\n");
             virBufferAdjustIndent(buf, 2);
-            if (def->target.perms.mode != (mode_t) -1)
-                virBufferAsprintf(buf, "<mode>0%o</mode>\n",
+            if (def->target.perms.mode != (mode_t) -1) {
+                if (def->target.perms.mode & (S_ISUID | S_ISGID | S_ISVTX))
+                    virBufferAsprintf(buf, "<mode>%4o</mode>\n",
                                   def->target.perms.mode);
+                else
+                    virBufferAsprintf(buf, "<mode>0%o</mode>\n",
+                                      def->target.perms.mode);
+            }
             if (def->target.perms.uid != (uid_t) -1)
                 virBufferAsprintf(buf, "<owner>%d</owner>\n",
                                   (int) def->target.perms.uid);
diff --git a/src/storage/storage_util.c b/src/storage/storage_util.c
index c2754dbb93..5352ab9120 100644
--- a/src/storage/storage_util.c
+++ b/src/storage/storage_util.c
@@ -82,6 +82,10 @@ VIR_LOG_INIT("storage.storage_util");
 # define S_IRWXUGO (S_IRWXU | S_IRWXG | S_IRWXO)
 #endif
 
+#ifndef S_IALLUGO
+# define S_IALLUGO (S_ISUID | S_ISGID | S_ISVTX | S_IRWXUGO)
+#endif
+
 /* virStorageBackendNamespaceInit:
  * @poolType: virStoragePoolType
  * @xmlns: Storage Pool specific namespace callback methods
@@ -512,7 +516,7 @@ virStorageBackendCreateExecCommand(virStoragePoolObjPtr pool,
 
         virCommandSetUID(cmd, vol->target.perms->uid);
         virCommandSetGID(cmd, vol->target.perms->gid);
-        virCommandSetUmask(cmd, S_IRWXUGO ^ mode);
+        virCommandSetUmask(cmd, S_IALLUGO ^ mode);
 
         if (virCommandRun(cmd, NULL) == 0) {
             /* command was successfully run, check if the file was created */
@@ -523,7 +527,7 @@ virStorageBackendCreateExecCommand(virStoragePoolObjPtr pool,
                  * If that doesn't match what we expect, then let's try to
                  * re-open the file and attempt to force the mode change.
                  */
-                if (mode != (st.st_mode & S_IRWXUGO)) {
+                if (mode != (st.st_mode & S_IALLUGO)) {
                     VIR_AUTOCLOSE fd = -1;
                     int flags = VIR_FILE_OPEN_FORK | VIR_FILE_OPEN_FORCE_MODE;
 
@@ -569,7 +573,7 @@ virStorageBackendCreateExecCommand(virStoragePoolObjPtr pool,
         goto cleanup;
     }
 
-    if (mode != (st.st_mode & S_IRWXUGO) &&
+    if (mode != (st.st_mode & S_IALLUGO) &&
         chmod(vol->target.path, mode) < 0) {
         virReportSystemError(errno,
                              _("cannot set mode of '%s' to %04o"),
@@ -1825,7 +1829,7 @@ virStorageBackendUpdateVolTargetInfoFD(virStorageSourcePtr target,
 
     if (!target->perms && VIR_ALLOC(target->perms) < 0)
         return -1;
-    target->perms->mode = sb->st_mode & S_IRWXUGO;
+    target->perms->mode = sb->st_mode & S_IALLUGO;
     target->perms->uid = sb->st_uid;
     target->perms->gid = sb->st_gid;
 
-- 
2.20.1