internal/acl: skip superfluous acl_set_file

This slightly reduces startup latency.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 65 insertions, 22 deletions

diff --git a/internal/acl/libacl-helper.c b/internal/acl/libacl-helper.c
index 259dfb2b..065c1928 100644
--- a/internal/acl/libacl-helper.c
+++ b/internal/acl/libacl-helper.c
@@ -4,18 +4,22 @@
 #include <stdlib.h>
 #include <sys/acl.h>
 
-int hakurei_acl_update_file_by_uid(const char *path_p, uid_t uid,
-                                   acl_perm_t *perms, size_t plen) {
-    int ret;
+enum hakurei_acl_status hakurei_update_acl(
+    const char *path_p,
+    uid_t uid,
+    acl_perm_t perms) {
+    enum hakurei_acl_status ret;
+
     bool v;
     int i;
-    acl_t acl;
+    acl_t acl, acl_d = NULL;
     acl_entry_t entry;
     acl_tag_t tag_type;
     void *qualifier_p;
     acl_permset_t permset;
+    acl_perm_t has_perms;
 
-    ret = -1; /* acl_get_file */
+    ret = HAKUREI_ACL_GET_FILE;
     acl = acl_get_file(path_p, ACL_TYPE_ACCESS);
     if (acl == NULL)
         goto out;
@@ -23,13 +27,13 @@ int hakurei_acl_update_file_by_uid(const char *path_p, uid_t uid,
     /* prune entries by uid */
     for (i = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry); i == 1;
          i = acl_get_entry(acl, ACL_NEXT_ENTRY, &entry)) {
-        ret = -2; /* acl_get_tag_type */
+        ret = HAKUREI_ACL_GET_TAG_TYPE;
         if (acl_get_tag_type(entry, &tag_type) != 0)
             goto out;
         if (tag_type != ACL_USER)
             continue;
 
-        ret = -3; /* acl_get_qualifier */
+        ret = HAKUREI_ACL_GET_QUALIFIER;
         qualifier_p = acl_get_qualifier(entry);
         if (qualifier_p == NULL)
             goto out;
@@ -39,52 +43,91 @@ int hakurei_acl_update_file_by_uid(const char *path_p, uid_t uid,
         if (!v)
             continue;
 
-        ret = -4; /* acl_delete_entry */
+        ret = HAKUREI_ACL_GET_PERMSET;
+        if (acl_get_permset(entry, &permset) != 0)
+            goto out;
+
+        if (perms == 0)
+            goto delete;
+
+        /* this is quite ugly, but the standard makes it impossible to directly
+         * obtain these bits */
+        has_perms = 0;
+#define COPY_PERM_BIT(perm)              \
+    do {                                 \
+        ret = HAKUREI_ACL_GET_PERM;      \
+        i = acl_get_perm(permset, perm); \
+        if (i < 0)                       \
+            goto out;                    \
+        if (i > 0)                       \
+            has_perms |= perm;           \
+    } while (0)
+        COPY_PERM_BIT(ACL_READ);
+        COPY_PERM_BIT(ACL_WRITE);
+        COPY_PERM_BIT(ACL_EXECUTE);
+
+        if (perms == has_perms) {
+            ret = HAKUREI_ACL_DUP;
+            acl_d = acl_dup(acl);
+            if (acl_d == NULL)
+                goto out;
+
+            ret = HAKUREI_ACL_CALC_MASK;
+            if (acl_calc_mask(&acl_d) != 0)
+                goto out;
+
+            ret = HAKUREI_ACL_OK;
+            if (acl_cmp(acl, acl_d) == 0)
+                goto out;
+        }
+
+    delete:
+        ret = HAKUREI_ACL_DELETE_ENTRY;
         if (acl_delete_entry(acl, entry) != 0)
             goto out;
     }
 
-    if (plen == 0)
+    if (perms == 0)
         goto set;
 
-    ret = -5; /* acl_create_entry */
+    ret = HAKUREI_ACL_CREATE_ENTRY;
     if (acl_create_entry(&acl, &entry) != 0)
         goto out;
 
-    ret = -6; /* acl_get_permset */
+    ret = HAKUREI_ACL_GET_PERMSET;
     if (acl_get_permset(entry, &permset) != 0)
         goto out;
 
-    ret = -7; /* acl_add_perm */
-    for (i = 0; i < plen; i++) {
-        if (acl_add_perm(permset, perms[i]) != 0)
-            goto out;
-    }
+    ret = HAKUREI_ACL_ADD_PERM;
+    if (acl_add_perm(permset, perms) != 0)
+        goto out;
 
-    ret = -8; /* acl_set_tag_type */
+    ret = HAKUREI_ACL_SET_TAG_TYPE;
     if (acl_set_tag_type(entry, ACL_USER) != 0)
         goto out;
 
-    ret = -9; /* acl_set_qualifier */
+    ret = HAKUREI_ACL_SET_QUALIFIER;
     if (acl_set_qualifier(entry, (void *)&uid) != 0)
         goto out;
 
 set:
-    ret = -10; /* acl_calc_mask */
+    ret = HAKUREI_ACL_CALC_MASK;
     if (acl_calc_mask(&acl) != 0)
         goto out;
 
-    ret = -11; /* acl_valid */
+    ret = HAKUREI_ACL_VALID;
     if (acl_valid(acl) != 0)
         goto out;
 
-    ret = -12; /* acl_set_file */
+    ret = HAKUREI_ACL_SET_FILE;
     if (acl_set_file(path_p, ACL_TYPE_ACCESS, acl) == 0)
-        ret = 0;
+        ret = HAKUREI_ACL_OK;
 
 out:
     free((void *)path_p);
     if (acl != NULL)
         acl_free((void *)acl);
+    if (acl_d != NULL)
+        acl_free((void *)acl_d);
     return ret;
 }