acl: implement Update in C

The original implementation was effectively just writing C in Go.

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

1 files changed, 69 insertions, 0 deletions

diff --git a/acl/acl-update.c b/acl/acl-update.c
new file mode 100644
index 00000000..1d83c15d
--- /dev/null
+++ b/acl/acl-update.c
@@ -0,0 +1,69 @@
+#include "acl-update.h"
+#include <stdlib.h>
+#include <stdbool.h>
+#include <sys/acl.h>
+#include <acl/libacl.h>
+
+int f_acl_update_file_by_uid(const char *path_p, uid_t uid, acl_perm_t *perms, size_t plen) {
+    int ret = -1;
+    bool v;
+    int i;
+    acl_t acl;
+    acl_entry_t entry;
+    acl_tag_t tag_type;
+    void *qualifier_p;
+    acl_permset_t permset;
+
+    acl = acl_get_file(path_p, ACL_TYPE_ACCESS);
+    if (acl == NULL)
+        goto out;
+
+    // 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)) {
+        if (acl_get_tag_type(entry, &tag_type) != 0)
+            return -1;
+        if (tag_type != ACL_USER)
+            continue;
+
+        qualifier_p = acl_get_qualifier(entry);
+        if (qualifier_p == NULL)
+            return -1;
+        v = *(uid_t *)qualifier_p == uid;
+        acl_free(qualifier_p);
+
+        if (!v)
+            continue;
+
+        acl_delete_entry(acl, entry);
+    }
+
+    if (plen == 0)
+        goto set;
+
+    if (acl_create_entry(&acl, &entry) != 0)
+        goto out;
+    if (acl_get_permset(entry, &permset) != 0)
+        goto out;
+    for (i = 0; i < plen; i++) {
+        if (acl_add_perm(permset, perms[i]) != 0)
+            goto out;
+    }
+    if (acl_set_tag_type(entry, ACL_USER) != 0)
+        goto out;
+    if (acl_set_qualifier(entry, (void *)&uid) != 0)
+        goto out;
+
+set:
+    if (acl_calc_mask(&acl) != 0)
+        goto out;
+    if (acl_valid(acl) != 0)
+        goto out;
+    if (acl_set_file(path_p, ACL_TYPE_ACCESS, acl) == 0)
+        ret = 0;
+
+out:
+    free((void *)path_p);
+    if (acl != NULL)
+        acl_free((void *)acl);
+    return ret;
+}