libmount: cleanup strdup() use in context, add reg.test

* don't ignore strdup() result
* cleanup mnt_context_prepare_helper() to have only one return point
  (due to mnt_context_switch_ns())
* add mnt_context_prepare_helper() test program

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libmount/src/context.c b/libmount/src/context.c
index bca0b4ca5568c643322b57ce578f86f340218299..8e1292522354050e4b6cc66b215ef8e371955980 100644 (file)
--- a/libmount/src/context.c
+++ b/libmount/src/context.c
@@ -218,12 +218,12 @@ struct libmnt_context *mnt_copy_context(struct libmnt_context *o)
        n->mtab = o->utab;
        mnt_ref_table(n->utab);
 
-       if (o->tgt_prefix)
-               n->tgt_prefix = strdup(o->tgt_prefix);
-       if (o->helper)
-               n->helper = strdup(o->helper);
-       if (o->orig_user)
-               n->orig_user = strdup(o->orig_user);
+       if (o->tgt_prefix && !(n->tgt_prefix = strdup(o->tgt_prefix)))
+               goto failed;
+       if (o->helper && !(n->helper = strdup(o->helper)))
+               goto failed;
+       if (o->orig_user && !(n->orig_user = strdup(o->orig_user)))
+               goto failed;
 
        n->mountflags = o->mountflags;
        n->mountdata = o->mountdata;
@@ -1880,12 +1880,16 @@ int mnt_context_guess_srcpath_fstype(struct libmnt_context *cxt, char **type)
 {
        int rc = 0;
        struct libmnt_ns *ns_old;
-       const char *dev = mnt_fs_get_srcpath(cxt->fs);
+       const char *dev;
+
+       assert(type);
+       assert(cxt);
 
        *type = NULL;
 
+       dev = mnt_fs_get_srcpath(cxt->fs);
        if (!dev)
-               goto done;
+               return 0;
 
        ns_old = mnt_context_switch_target_ns(cxt);
        if (!ns_old)
@@ -1896,22 +1900,30 @@ int mnt_context_guess_srcpath_fstype(struct libmnt_context *cxt, char **type)
                int ambi = 0;
 
                *type = mnt_get_fstype(dev, &ambi, cache);
-               if (cache && *type)
-                       *type = strdup(*type);
                if (ambi)
                        rc = -MNT_ERR_AMBIFS;
+
+               if (cache && *type) {
+                       *type = strdup(*type);
+                       if (!*type)
+                               rc = -ENOMEM;
+               }
        } else {
                DBG(CXT, ul_debugobj(cxt, "access(%s) failed [%m]", dev));
-               if (strchr(dev, ':') != NULL)
+               if (strchr(dev, ':') != NULL) {
                        *type = strdup("nfs");
-               else if (!strncmp(dev, "//", 2))
+                       if (!*type)
+                               rc = -ENOMEM;
+               } else if (!strncmp(dev, "//", 2)) {
                        *type = strdup("cifs");
+                       if (!*type)
+                               rc = -ENOMEM;
+               }
        }
 
        if (!mnt_context_switch_ns(cxt, ns_old))
                return -MNT_ERR_NAMESPACE;
 
-done:
        return rc;
 }
 
@@ -1973,6 +1985,7 @@ int mnt_context_prepare_helper(struct libmnt_context *cxt, const char *name,
        char search_path[] = FS_SEARCH_PATH;            /* from config.h */
        char *p = NULL, *path;
        struct libmnt_ns *ns_old;
+       int rc = 0;
 
        assert(cxt);
        assert(cxt->fs);
@@ -1995,46 +2008,50 @@ int mnt_context_prepare_helper(struct libmnt_context *cxt, const char *name,
        if (!ns_old)
                return -MNT_ERR_NAMESPACE;
 
+       /* Ignore errors when search in $PATH and do not modify
+        * @rc due to stat() etc.
+        */
        path = strtok_r(search_path, ":", &p);
        while (path) {
                char helper[PATH_MAX];
                struct stat st;
-               int rc;
+               int xrc;
 
-               rc = snprintf(helper, sizeof(helper), "%s/%s.%s",
+               xrc = snprintf(helper, sizeof(helper), "%s/%s.%s",
                                                path, name, type);
                path = strtok_r(NULL, ":", &p);
 
-               if (rc < 0 || (size_t) rc >= sizeof(helper))
+               if (xrc < 0 || (size_t) xrc >= sizeof(helper))
                        continue;
 
-               rc = stat(helper, &st);
+               xrc = stat(helper, &st);
                if (rc == -1 && errno == ENOENT && strchr(type, '.')) {
                        /* If type ends with ".subtype" try without it */
                        char *hs = strrchr(helper, '.');
                        if (hs)
                                *hs = '\0';
-                       rc = stat(helper, &st);
+                       xrc = stat(helper, &st);
                }
 
                DBG(CXT, ul_debugobj(cxt, "%-25s ... %s", helper,
-                                       rc ? "not found" : "found"));
-               if (rc)
+                                       xrc ? "not found" : "found"));
+               if (xrc)
                        continue;
 
-               if (!mnt_context_switch_ns(cxt, ns_old))
-                       return -MNT_ERR_NAMESPACE;
-
-               free(cxt->helper);
-               cxt->helper = strdup(helper);
-               if (!cxt->helper)
-                       return -ENOMEM;
-               return 0;
+               /* success */
+               rc = strdup_to_struct_member(cxt, helper, helper);
+               break;
        }
 
        if (!mnt_context_switch_ns(cxt, ns_old))
-               return -MNT_ERR_NAMESPACE;
-       return 0;
+               rc = -MNT_ERR_NAMESPACE;
+
+       /* make sure helper is not set on error */
+       if (rc) {
+               free(cxt->helper);
+               cxt->helper = NULL;
+       }
+       return rc;
 }
 
 int mnt_context_merge_mflags(struct libmnt_context *cxt)
@@ -3053,6 +3070,32 @@ struct libmnt_ns *mnt_context_switch_target_ns(struct libmnt_context *cxt)
 
 #ifdef TEST_PROGRAM
 
+static int test_search_helper(struct libmnt_test *ts, int argc, char *argv[])
+{
+       struct libmnt_context *cxt;
+       const char *type;
+       int rc;
+
+       if (argc < 2)
+               return -EINVAL;
+
+       cxt = mnt_new_context();
+       if (!cxt)
+               return -ENOMEM;
+
+       type = argv[1];
+
+       mnt_context_get_fs(cxt);                /* just to fill cxt->fs */
+       cxt->flags |= MNT_FL_MOUNTFLAGS_MERGED; /* fake */
+
+       rc = mnt_context_prepare_helper(cxt, "mount", type);
+       printf("helper is: %s\n", cxt->helper ? cxt->helper : "not found");
+
+       mnt_free_context(cxt);
+       return rc;
+}
+
+
 static struct libmnt_lock *lock;
 
 static void lock_fallback(void)
@@ -3258,6 +3301,7 @@ int main(int argc, char *argv[])
        { "--umount", test_umount, "[-t <type>] [-f][-l][-r] <src>|<target>" },
        { "--mount-all", test_mountall,  "[-O <pattern>] [-t <pattern] mount all filesystems from fstab" },
        { "--flags", test_flags,   "[-o <opts>] <spec>" },
+       { "--search-helper", test_search_helper, "<fstype>" },
        { NULL }};
 
        umask(S_IWGRP|S_IWOTH); /* to be compatible with mount(8) */