From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 27 Sep 2023 19:55:21 +0000 (+0900)
Subject: sd-journal: make journal_file_next_entry() always return the nearest entry object
X-Git-Tag: v255-rc1~315^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=77db35bf10c39861a81a5c35aeff1260342f68d2;p=thirdparty%2Fsystemd.git

sd-journal: make journal_file_next_entry() always return the nearest entry object

Previously, if the input offset 'p' does not point to an entry object,
the function returns the next of the nearest entry object on
DIRECTION_DOWN, as generic_array_bisect() already returns the nearest
entry object.
---

diff --git a/src/libsystemd/sd-journal/journal-file.c b/src/libsystemd/sd-journal/journal-file.c
index 750f05d80b5..5982938fb92 100644
--- a/src/libsystemd/sd-journal/journal-file.c
+++ b/src/libsystemd/sd-journal/journal-file.c
@@ -3397,7 +3397,8 @@ int journal_file_next_entry(
                 Object **ret_object,
                 uint64_t *ret_offset) {
 
-        uint64_t i, n, ofs;
+        uint64_t i, n, q;
+        Object *o;
         int r;
 
         assert(f);
@@ -3409,38 +3410,53 @@ int journal_file_next_entry(
         if (n <= 0)
                 return 0;
 
+        /* When the input offset 'p' is zero, return the first (or last on DIRECTION_UP) entry. */
         if (p == 0)
-                i = direction == DIRECTION_DOWN ? 0 : n - 1;
-        else {
-                r = generic_array_bisect(f,
+                return generic_array_get(f,
                                          le64toh(f->header->entry_array_offset),
-                                         le64toh(f->header->n_entries),
-                                         p,
-                                         test_object_offset,
-                                         DIRECTION_DOWN,
-                                         NULL, NULL,
-                                         &i);
-                if (r <= 0)
-                        return r;
+                                         direction == DIRECTION_DOWN ? 0 : n - 1,
+                                         direction,
+                                         ret_object, ret_offset);
+
+        /* Otherwise, first find the nearest entry object. */
+        r = generic_array_bisect(f,
+                                 le64toh(f->header->entry_array_offset),
+                                 le64toh(f->header->n_entries),
+                                 p,
+                                 test_object_offset,
+                                 direction,
+                                 ret_object ? &o : NULL, &q, &i);
+        if (r <= 0)
+                return r;
 
-                r = bump_array_index(&i, direction, n);
-                if (r <= 0)
-                        return r;
-        }
+        assert(direction == DIRECTION_DOWN ? p <= q : q <= p);
+
+        /* If the input offset 'p' points to an entry object, generic_array_bisect() should provides
+         * the same offset, and the index needs to be shifted. Otherwise, use the found object as is,
+         * as it is the nearest entry object from the input offset 'p'. */
+
+        if (p != q)
+                goto found;
+
+        r = bump_array_index(&i, direction, n);
+        if (r <= 0)
+                return r;
 
         /* And jump to it */
-        r = generic_array_get(f, le64toh(f->header->entry_array_offset), i, direction, ret_object, &ofs);
+        r = generic_array_get(f, le64toh(f->header->entry_array_offset), i, direction, ret_object ? &o : NULL, &q);
         if (r <= 0)
                 return r;
 
         /* Ensure our array is properly ordered. */
-        if (p > 0 && !check_properly_ordered(ofs, p, direction))
+        if (!check_properly_ordered(q, p, direction))
                 return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG),
-                                       "%s: entry array not properly ordered at entry %" PRIu64,
+                                       "%s: entry array not properly ordered at entry index %" PRIu64,
                                        f->path, i);
-
+found:
+        if (ret_object)
+                *ret_object = o;
         if (ret_offset)
-                *ret_offset = ofs;
+                *ret_offset = q;
 
         return 1;
 }