env: Allow returning errors from hdelete_r()

At present this function returns 1 on success and 0 on failure. But in
the latter case it provides no indication of what went wrong.

If an attempt is made to delete a non-existent variable, the caller may
want to ignore this error. This happens when setting a non-existent
variable to "", for example.

Update the function to return 0 on success and a useful error code on
failure. Add a function comment too.

Make sure that env_set() does not return an error if it is deleting a
variable that doesn't exist. We could update env_set() to return useful
error numbers also, but that is beyond the scope of this change.

Signed-off-by: Simon Glass <sjg@chromium.org>
wip

diff --git a/cmd/nvedit.c b/cmd/nvedit.c
index 7fce723800d618c5a50d37cbe1ec520a73b5d669..d0d2eca904729089802a3a62b4e7922bf4f6e450 100644 (file)
--- a/cmd/nvedit.c
+++ b/cmd/nvedit.c
@@ -266,7 +266,9 @@ static int _do_env_set(int flag, int argc, char *const argv[], int env_flag)
        /* Delete only ? */
        if (argc < 3 || argv[2] == NULL) {
                int rc = hdelete_r(name, &env_htab, env_flag);
-               return !rc;
+
+               /* If the variable didn't exist, don't report an error */
+               return rc && rc != -ENOENT ? 1 : 0;
        }
 
        /*
@@ -895,7 +897,7 @@ static int do_env_delete(struct cmd_tbl *cmdtp, int flag,
        while (--argc > 0) {
                char *name = *++argv;
 
-               if (!hdelete_r(name, &env_htab, env_flag))
+               if (hdelete_r(name, &env_htab, env_flag))
                        ret = 1;
        }
 

diff --git a/include/search.h b/include/search.h
index e56843c26fdab07973b93c37c7501e64b00bd963..d0bb44388e19041b5d20f0398a4630a937743b9a 100644 (file)
--- a/include/search.h
+++ b/include/search.h
@@ -80,7 +80,16 @@ int hsearch_r(struct env_entry item, enum env_action action,
 int hmatch_r(const char *match, int last_idx, struct env_entry **retval,
             struct hsearch_data *htab);
 
-/* Search and delete entry matching "key" in internal hash table. */
+/**
+ * hdelete_r() - Search and delete entry in internal hash table
+ *
+ * @key: Name of entry to delete
+ * @htab: Hash table
+ * @flag: Flags to use (H_...)
+ * @return 0 on success, -ENOENT if not found, -EPERM if the hash table callback
+ *     rejected changing the variable, -EINVAL if the hash table refused to
+ *     delete the variable
+ */
 int hdelete_r(const char *key, struct hsearch_data *htab, int flag);
 
 ssize_t hexport_r(struct hsearch_data *htab, const char sep, int flag,

diff --git a/lib/hashtable.c b/lib/hashtable.c
index 7c08f5c8055151b9c57577b8e273cbc4a9ddc239..ff5ff7263949f532d7792deb70677df7ab3f65a7 100644 (file)
--- a/lib/hashtable.c
+++ b/lib/hashtable.c
@@ -472,7 +472,7 @@ int hdelete_r(const char *key, struct hsearch_data *htab, int flag)
        idx = hsearch_r(e, ENV_FIND, &ep, htab, 0);
        if (idx == 0) {
                __set_errno(ESRCH);
-               return 0;       /* not found */
+               return -ENOENT; /* not found */
        }
 
        /* Check for permission */
@@ -481,7 +481,7 @@ int hdelete_r(const char *key, struct hsearch_data *htab, int flag)
                debug("change_ok() rejected deleting variable "
                        "%s, skipping it!\n", key);
                __set_errno(EPERM);
-               return 0;
+               return -EPERM;
        }
 
        /* If there is a callback, call it */
@@ -490,12 +490,12 @@ int hdelete_r(const char *key, struct hsearch_data *htab, int flag)
                debug("callback() rejected deleting variable "
                        "%s, skipping it!\n", key);
                __set_errno(EINVAL);
-               return 0;
+               return -EINVAL;
        }
 
        _hdelete(key, htab, ep, idx);
 
-       return 1;
+       return 0;
 }
 
 #if !(defined(CONFIG_SPL_BUILD) && !defined(CONFIG_SPL_SAVEENV))
@@ -917,7 +917,7 @@ int himport_r(struct hsearch_data *htab,
                        if (!drop_var_from_set(name, nvars, localvars))
                                continue;
 
-                       if (hdelete_r(name, htab, flag) == 0)
+                       if (hdelete_r(name, htab, flag))
                                debug("DELETE ERROR ##############################\n");
 
                        continue;
@@ -979,7 +979,7 @@ int himport_r(struct hsearch_data *htab,
                 * b) if the variable was not present in current env, we notify
                 *    it might be a typo
                 */
-               if (hdelete_r(localvars[i], htab, flag) == 0)
+               if (hdelete_r(localvars[i], htab, flag))
                        printf("WARNING: '%s' neither in running nor in imported env!\n", localvars[i]);
                else
                        printf("WARNING: '%s' not in imported env, deleting it!\n", localvars[i]);

diff --git a/test/env/hashtable.c b/test/env/hashtable.c
index 339cc19ba14a0ef3fd2af82f892345c0f06ff966..70102f9121c271d00b851ed074ac9f4df11472f9 100644 (file)
--- a/test/env/hashtable.c
+++ b/test/env/hashtable.c
@@ -80,7 +80,7 @@ static int htab_create_delete(struct unit_test_state *uts,
                ut_asserteq_str(key, ritem->key);
                ut_asserteq_str(key, ritem->data);
 
-               ut_asserteq(1, hdelete_r(key, htab, 0));
+               ut_asserteq(0, hdelete_r(key, htab, 0));
        }
 
        return 0;