From 57ba83ddd33d8ed5e8cee6a35f6ee780532a7a0d Mon Sep 17 00:00:00 2001
From: Daan De Meyer <daan.j.demeyer@gmail.com>
Date: Tue, 25 Jan 2022 11:50:40 +0000
Subject: [PATCH] journal: Only move to objects when necessary

Conflict:don't modify journal_file_read_object because 117e2112 isn't merged;
don't modify generic_array_get because 8d801e35cb isn't merged; adapt context
Reference:https://github.com/systemd/systemd/commit/ded10e3a5f4c9a9fca9a57f5feb7e77db4155dbd

Let's make sure we only move to objects when it's required. If "ret"
is NULL, the caller isn't interested in the actual object and the
function being called shouldn't move to it unless it has to
inspect/modify the object itself.
---
 src/libsystemd/sd-journal/journal-file.c | 99 +++++++++--------------
 1 file changed, 39 insertions(+), 60 deletions(-)

diff --git a/src/libsystemd/sd-journal/journal-file.c b/src/libsystemd/sd-journal/journal-file.c
index e3e926b..efc5018 100644
--- a/src/libsystemd/sd-journal/journal-file.c
+++ b/src/libsystemd/sd-journal/journal-file.c
@@ -931,7 +931,6 @@ int journal_file_move_to_object(JournalFile *f, ObjectType type, uint64_t offset
         uint64_t s;
 
         assert(f);
-        assert(ret);
 
         /* Objects may only be located at multiple of 64 bit */
         if (!VALID64(offset))
@@ -986,7 +985,9 @@ int journal_file_move_to_object(JournalFile *f, ObjectType type, uint64_t offset
         if (r < 0)
                 return r;
 
-        *ret = o;
+        if (ret)
+                *ret = o;
+
         return 0;
 }
 
@@ -1584,19 +1585,11 @@ static int journal_file_append_field(
 
         hash = journal_file_hash_data(f, field, size);
 
-        r = journal_file_find_field_object_with_hash(f, field, size, hash, &o, &p);
+        r = journal_file_find_field_object_with_hash(f, field, size, hash, ret, ret_offset);
         if (r < 0)
                 return r;
-        if (r > 0) {
-
-                if (ret)
-                        *ret = o;
-
-                if (ret_offset)
-                        *ret_offset = p;
-
+        if (r > 0)
                 return 0;
-        }
 
         osize = offsetof(Object, field.payload) + size;
         r = journal_file_append_object(f, OBJECT_FIELD, osize, &o, &p);
@@ -1610,20 +1603,20 @@ static int journal_file_append_field(
         if (r < 0)
                 return r;
 
-        /* The linking might have altered the window, so let's
-         * refresh our pointer */
-        r = journal_file_move_to_object(f, OBJECT_FIELD, p, &o);
-        if (r < 0)
-                return r;
+        /* The linking might have altered the window, so let's only pass the offset to hmac which will
+         * move to the object again if needed. */
 
 #if HAVE_GCRYPT
-        r = journal_file_hmac_put_object(f, OBJECT_FIELD, o, p);
+        r = journal_file_hmac_put_object(f, OBJECT_FIELD, NULL, p);
         if (r < 0)
                 return r;
 #endif
 
-        if (ret)
-                *ret = o;
+        if (ret) {
+                r = journal_file_move_to_object(f, OBJECT_FIELD, p, ret);
+                if (r < 0)
+                        return r;
+        }
 
         if (ret_offset)
                 *ret_offset = p;
@@ -1647,19 +1640,11 @@ static int journal_file_append_data(
 
         hash = journal_file_hash_data(f, data, size);
 
-        r = journal_file_find_data_object_with_hash(f, data, size, hash, &o, &p);
+        r = journal_file_find_data_object_with_hash(f, data, size, hash, ret, ret_offset);
         if (r < 0)
                 return r;
-        if (r > 0) {
-
-                if (ret)
-                        *ret = o;
-
-                if (ret_offset)
-                        *ret_offset = p;
-
+        if (r > 0)
                 return 0;
-        }
 
         osize = offsetof(Object, data.payload) + size;
         r = journal_file_append_object(f, OBJECT_DATA, osize, &o, &p);
@@ -1693,17 +1678,16 @@ static int journal_file_append_data(
         if (r < 0)
                 return r;
 
-#if HAVE_GCRYPT
-        r = journal_file_hmac_put_object(f, OBJECT_DATA, o, p);
+        /* The linking might have altered the window, so let's refresh our pointer. */
+        r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
         if (r < 0)
                 return r;
-#endif
 
-        /* The linking might have altered the window, so let's
-         * refresh our pointer */
-        r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
+#if HAVE_GCRYPT
+        r = journal_file_hmac_put_object(f, OBJECT_DATA, o, p);
         if (r < 0)
                 return r;
+#endif
 
         if (!data)
                 eq = NULL;
@@ -2307,20 +2290,15 @@ static int generic_array_get_plus_one(
                 uint64_t i,
                 Object **ret, uint64_t *ret_offset) {
 
-        Object *o;
-
         assert(f);
 
         if (i == 0) {
                 int r;
 
-                r = journal_file_move_to_object(f, OBJECT_ENTRY, extra, &o);
+                r = journal_file_move_to_object(f, OBJECT_ENTRY, extra, ret);
                 if (r < 0)
                         return r;
 
-                if (ret)
-                        *ret = o;
-
                 if (ret_offset)
                         *ret_offset = extra;
 
@@ -2349,7 +2327,7 @@ static int generic_array_bisect(
 
         uint64_t a, p, t = 0, i = 0, last_p = 0, last_index = UINT64_MAX;
         bool subtract_one = false;
-        Object *o, *array = NULL;
+        Object *array = NULL;
         int r;
         ChainCacheItem *ci;
 
@@ -2537,12 +2515,11 @@ found:
         else
                 p = le64toh(array->entry_array.items[i]);
 
-        r = journal_file_move_to_object(f, OBJECT_ENTRY, p, &o);
-        if (r < 0)
-                return r;
-
-        if (ret)
-                *ret = o;
+        if (ret) {
+                r = journal_file_move_to_object(f, OBJECT_ENTRY, p, ret);
+                if (r < 0)
+                        return r;
+        }
 
         if (ret_offset)
                 *ret_offset = p;
@@ -2567,7 +2544,6 @@ static int generic_array_bisect_plus_one(
 
         int r;
         bool step_back = false;
-        Object *o;
 
         assert(f);
         assert(test_object);
@@ -2610,12 +2586,11 @@ static int generic_array_bisect_plus_one(
         return r;
 
 found:
-        r = journal_file_move_to_object(f, OBJECT_ENTRY, extra, &o);
-        if (r < 0)
-                return r;
-
-        if (ret)
-                *ret = o;
+        if (ret) {
+                r = journal_file_move_to_object(f, OBJECT_ENTRY, extra, ret);
+                if (r < 0)
+                        return r;
+        }
 
         if (ret_offset)
                 *ret_offset = extra;
@@ -3088,7 +3063,6 @@ int journal_file_move_to_entry_by_monotonic_for_data(
          * exists in both bisection arrays */
 
         for (;;) {
-                Object *qo;
                 uint64_t p, q;
 
                 r = journal_file_move_to_object(f, OBJECT_DATA, data_offset, &d);
@@ -3117,14 +3091,18 @@ int journal_file_move_to_entry_by_monotonic_for_data(
                                                   p,
                                                   test_object_offset,
                                                   direction,
-                                                  &qo, &q, NULL);
+                                                  NULL, &q, NULL);
 
                 if (r <= 0)
                         return r;
 
                 if (p == q) {
-                        if (ret)
-                                *ret = qo;
+                        if (ret) {
+                                r = journal_file_move_to_object(f, OBJECT_ENTRY, q, ret);
+                                if (r < 0)
+                                        return r;
+                        }
+
                         if (ret_offset)
                                 *ret_offset = q;
 
-- 
2.23.0