Move the server's backup manifest code to a separate file.
authorRobert Haas <rhaas@postgresql.org>
Mon, 20 Apr 2020 18:37:38 +0000 (14:37 -0400)
committerRobert Haas <rhaas@postgresql.org>
Mon, 20 Apr 2020 18:38:15 +0000 (14:38 -0400)
basebackup.c is already a pretty big and complicated file, so it
makes more sense to keep the backup manifest support routines
in a separate file, for clarity and ease of maintenance.

Discussion: http://postgr.es/m/CA+TgmoavRak5OdP76P8eJExDYhPEKWjMb0sxW7dF01dWFgE=uA@mail.gmail.com

src/backend/replication/Makefile
src/backend/replication/backup_manifest.c [new file with mode: 0644]
src/backend/replication/basebackup.c
src/include/replication/backup_manifest.h [new file with mode: 0644]

index fd08f093e1db5b94f028258c886967abe51a7e16..a0381e52f3139b5244c44b527dc8161ab89bf3dd 100644 (file)
@@ -15,6 +15,7 @@ include $(top_builddir)/src/Makefile.global
 override CPPFLAGS := -I. -I$(srcdir) $(CPPFLAGS)
 
 OBJS = \
+   backup_manifest.o \
    basebackup.o \
    repl_gram.o \
    slot.o \
diff --git a/src/backend/replication/backup_manifest.c b/src/backend/replication/backup_manifest.c
new file mode 100644 (file)
index 0000000..8aead70
--- /dev/null
@@ -0,0 +1,375 @@
+/*-------------------------------------------------------------------------
+ *
+ * backup_manifest.c
+ *   code for generating and sending a backup manifest
+ *
+ * Portions Copyright (c) 2010-2020, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *   src/backend/replication/backup_manifest.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/timeline.h"
+#include "libpq/libpq.h"
+#include "libpq/pqformat.h"
+#include "mb/pg_wchar.h"
+#include "replication/backup_manifest.h"
+#include "utils/builtins.h"
+#include "utils/json.h"
+
+/*
+ * Does the user want a backup manifest?
+ *
+ * It's simplest to always have a manifest_info object, so that we don't need
+ * checks for NULL pointers in too many places. However, if the user doesn't
+ * want a manifest, we set manifest->buffile to NULL.
+ */
+static inline bool
+IsManifestEnabled(manifest_info *manifest)
+{
+   return (manifest->buffile != NULL);
+}
+
+/*
+ * Convenience macro for appending data to the backup manifest.
+ */
+#define AppendToManifest(manifest, ...) \
+   { \
+       char *_manifest_s = psprintf(__VA_ARGS__);  \
+       AppendStringToManifest(manifest, _manifest_s);  \
+       pfree(_manifest_s); \
+   }
+
+/*
+ * Initialize state so that we can construct a backup manifest.
+ *
+ * NB: Although the checksum type for the data files is configurable, the
+ * checksum for the manifest itself always uses SHA-256. See comments in
+ * SendBackupManifest.
+ */
+void
+InitializeManifest(manifest_info *manifest, manifest_option want_manifest,
+                  pg_checksum_type manifest_checksum_type)
+{
+   if (want_manifest == MANIFEST_OPTION_NO)
+       manifest->buffile = NULL;
+   else
+       manifest->buffile = BufFileCreateTemp(false);
+   manifest->checksum_type = manifest_checksum_type;
+   pg_sha256_init(&manifest->manifest_ctx);
+   manifest->manifest_size = UINT64CONST(0);
+   manifest->force_encode = (want_manifest == MANIFEST_OPTION_FORCE_ENCODE);
+   manifest->first_file = true;
+   manifest->still_checksumming = true;
+
+   if (want_manifest != MANIFEST_OPTION_NO)
+       AppendToManifest(manifest,
+                        "{ \"PostgreSQL-Backup-Manifest-Version\": 1,\n"
+                        "\"Files\": [");
+}
+
+/*
+ * Append a cstring to the manifest.
+ */
+void
+AppendStringToManifest(manifest_info *manifest, char *s)
+{
+   int         len = strlen(s);
+   size_t      written;
+
+   Assert(manifest != NULL);
+   if (manifest->still_checksumming)
+       pg_sha256_update(&manifest->manifest_ctx, (uint8 *) s, len);
+   written = BufFileWrite(manifest->buffile, s, len);
+   if (written != len)
+       ereport(ERROR,
+               (errcode_for_file_access(),
+                errmsg("could not write to temporary file: %m")));
+   manifest->manifest_size += len;
+}
+
+/*
+ * Add an entry to the backup manifest for a file.
+ */
+void
+AddFileToManifest(manifest_info *manifest, const char *spcoid,
+                 const char *pathname, size_t size, pg_time_t mtime,
+                 pg_checksum_context *checksum_ctx)
+{
+   char        pathbuf[MAXPGPATH];
+   int         pathlen;
+   StringInfoData buf;
+
+   if (!IsManifestEnabled(manifest))
+       return;
+
+   /*
+    * If this file is part of a tablespace, the pathname passed to this
+    * function will be relative to the tar file that contains it. We want the
+    * pathname relative to the data directory (ignoring the intermediate
+    * symlink traversal).
+    */
+   if (spcoid != NULL)
+   {
+       snprintf(pathbuf, sizeof(pathbuf), "pg_tblspc/%s/%s", spcoid,
+                pathname);
+       pathname = pathbuf;
+   }
+
+   /*
+    * Each file's entry needs to be separated from any entry that follows by a
+    * comma, but there's no comma before the first one or after the last one.
+    * To make that work, adding a file to the manifest starts by terminating
+    * the most recently added line, with a comma if appropriate, but does not
+    * terminate the line inserted for this file.
+    */
+   initStringInfo(&buf);
+   if (manifest->first_file)
+   {
+       appendStringInfoString(&buf, "\n");
+       manifest->first_file = false;
+   }
+   else
+       appendStringInfoString(&buf, ",\n");
+
+   /*
+    * Write the relative pathname to this file out to the manifest. The
+    * manifest is always stored in UTF-8, so we have to encode paths that are
+    * not valid in that encoding.
+    */
+   pathlen = strlen(pathname);
+   if (!manifest->force_encode &&
+       pg_verify_mbstr(PG_UTF8, pathname, pathlen, true))
+   {
+       appendStringInfoString(&buf, "{ \"Path\": ");
+       escape_json(&buf, pathname);
+       appendStringInfoString(&buf, ", ");
+   }
+   else
+   {
+       appendStringInfoString(&buf, "{ \"Encoded-Path\": \"");
+       enlargeStringInfo(&buf, 2 * pathlen);
+       buf.len += hex_encode((char *) pathname, pathlen,
+                             &buf.data[buf.len]);
+       appendStringInfoString(&buf, "\", ");
+   }
+
+   appendStringInfo(&buf, "\"Size\": %zu, ", size);
+
+   /*
+    * Convert last modification time to a string and append it to the
+    * manifest. Since it's not clear what time zone to use and since time
+    * zone definitions can change, possibly causing confusion, use GMT
+    * always.
+    */
+   appendStringInfoString(&buf, "\"Last-Modified\": \"");
+   enlargeStringInfo(&buf, 128);
+   buf.len += pg_strftime(&buf.data[buf.len], 128, "%Y-%m-%d %H:%M:%S %Z",
+                          pg_gmtime(&mtime));
+   appendStringInfoString(&buf, "\"");
+
+   /* Add checksum information. */
+   if (checksum_ctx->type != CHECKSUM_TYPE_NONE)
+   {
+       uint8       checksumbuf[PG_CHECKSUM_MAX_LENGTH];
+       int         checksumlen;
+
+       checksumlen = pg_checksum_final(checksum_ctx, checksumbuf);
+
+       appendStringInfo(&buf,
+                        ", \"Checksum-Algorithm\": \"%s\", \"Checksum\": \"",
+                        pg_checksum_type_name(checksum_ctx->type));
+       enlargeStringInfo(&buf, 2 * checksumlen);
+       buf.len += hex_encode((char *) checksumbuf, checksumlen,
+                             &buf.data[buf.len]);
+       appendStringInfoString(&buf, "\"");
+   }
+
+   /* Close out the object. */
+   appendStringInfoString(&buf, " }");
+
+   /* OK, add it to the manifest. */
+   AppendStringToManifest(manifest, buf.data);
+
+   /* Avoid leaking memory. */
+   pfree(buf.data);
+}
+
+/*
+ * Add information about the WAL that will need to be replayed when restoring
+ * this backup to the manifest.
+ */
+void
+AddWALInfoToManifest(manifest_info *manifest, XLogRecPtr startptr,
+                    TimeLineID starttli, XLogRecPtr endptr, TimeLineID endtli)
+{
+   List       *timelines;
+   ListCell   *lc;
+   bool        first_wal_range = true;
+   bool        found_start_timeline = false;
+
+   if (!IsManifestEnabled(manifest))
+       return;
+
+   /* Terminate the list of files. */
+   AppendStringToManifest(manifest, "\n],\n");
+
+   /* Read the timeline history for the ending timeline. */
+   timelines = readTimeLineHistory(endtli);
+
+   /* Start a list of LSN ranges. */
+   AppendStringToManifest(manifest, "\"WAL-Ranges\": [\n");
+
+   foreach(lc, timelines)
+   {
+       TimeLineHistoryEntry *entry = lfirst(lc);
+       XLogRecPtr  tl_beginptr;
+
+       /*
+        * We only care about timelines that were active during the backup.
+        * Skip any that ended before the backup started. (Note that if
+        * entry->end is InvalidXLogRecPtr, it means that the timeline has not
+        * yet ended.)
+        */
+       if (!XLogRecPtrIsInvalid(entry->end) && entry->end < startptr)
+           continue;
+
+       /*
+        * Because the timeline history file lists newer timelines before
+        * older ones, the first timeline we encounter that is new enough to
+        * matter ought to match the ending timeline of the backup.
+        */
+       if (first_wal_range && endtli != entry->tli)
+           ereport(ERROR,
+                   errmsg("expected end timeline %u but found timeline %u",
+                          starttli, entry->tli));
+
+       if (!XLogRecPtrIsInvalid(entry->begin))
+           tl_beginptr = entry->begin;
+       else
+       {
+           tl_beginptr = startptr;
+
+           /*
+            * If we reach a TLI that has no valid beginning LSN, there can't
+            * be any more timelines in the history after this point, so we'd
+            * better have arrived at the expected starting TLI. If not,
+            * something's gone horribly wrong.
+            */
+           if (starttli != entry->tli)
+               ereport(ERROR,
+                       errmsg("expected start timeline %u but found timeline %u",
+                              starttli, entry->tli));
+       }
+
+       AppendToManifest(manifest,
+                        "%s{ \"Timeline\": %u, \"Start-LSN\": \"%X/%X\", \"End-LSN\": \"%X/%X\" }",
+                        first_wal_range ? "" : ",\n",
+                        entry->tli,
+                        (uint32) (tl_beginptr >> 32), (uint32) tl_beginptr,
+                        (uint32) (endptr >> 32), (uint32) endptr);
+
+       if (starttli == entry->tli)
+       {
+           found_start_timeline = true;
+           break;
+       }
+
+       endptr = entry->begin;
+       first_wal_range = false;
+   }
+
+   /*
+    * The last entry in the timeline history for the ending timeline should
+    * be the ending timeline itself. Verify that this is what we observed.
+    */
+   if (!found_start_timeline)
+       ereport(ERROR,
+               errmsg("start timeline %u not found history of timeline %u",
+                      starttli, endtli));
+
+   /* Terminate the list of WAL ranges. */
+   AppendStringToManifest(manifest, "\n],\n");
+}
+
+/*
+ * Finalize the backup manifest, and send it to the client.
+ */
+void
+SendBackupManifest(manifest_info *manifest)
+{
+   StringInfoData protobuf;
+   uint8       checksumbuf[PG_SHA256_DIGEST_LENGTH];
+   char        checksumstringbuf[PG_SHA256_DIGEST_STRING_LENGTH];
+   size_t      manifest_bytes_done = 0;
+
+   if (!IsManifestEnabled(manifest))
+       return;
+
+   /*
+    * Append manifest checksum, so that the problems with the manifest itself
+    * can be detected.
+    *
+    * We always use SHA-256 for this, regardless of what algorithm is chosen
+    * for checksumming the files.  If we ever want to make the checksum
+    * algorithm used for the manifest file variable, the client will need a
+    * way to figure out which algorithm to use as close to the beginning of
+    * the manifest file as possible, to avoid having to read the whole thing
+    * twice.
+    */
+   manifest->still_checksumming = false;
+   pg_sha256_final(&manifest->manifest_ctx, checksumbuf);
+   AppendStringToManifest(manifest, "\"Manifest-Checksum\": \"");
+   hex_encode((char *) checksumbuf, sizeof checksumbuf, checksumstringbuf);
+   checksumstringbuf[PG_SHA256_DIGEST_STRING_LENGTH - 1] = '\0';
+   AppendStringToManifest(manifest, checksumstringbuf);
+   AppendStringToManifest(manifest, "\"}\n");
+
+   /*
+    * We've written all the data to the manifest file.  Rewind the file so
+    * that we can read it all back.
+    */
+   if (BufFileSeek(manifest->buffile, 0, 0L, SEEK_SET))
+       ereport(ERROR,
+               (errcode_for_file_access(),
+                errmsg("could not rewind temporary file: %m")));
+
+   /* Send CopyOutResponse message */
+   pq_beginmessage(&protobuf, 'H');
+   pq_sendbyte(&protobuf, 0);  /* overall format */
+   pq_sendint16(&protobuf, 0); /* natts */
+   pq_endmessage(&protobuf);
+
+   /*
+    * Send CopyData messages.
+    *
+    * We choose to read back the data from the temporary file in chunks of
+    * size BLCKSZ; this isn't necessary, but buffile.c uses that as the I/O
+    * size, so it seems to make sense to match that value here.
+    */
+   while (manifest_bytes_done < manifest->manifest_size)
+   {
+       char        manifestbuf[BLCKSZ];
+       size_t      bytes_to_read;
+       size_t      rc;
+
+       bytes_to_read = Min(sizeof(manifestbuf),
+                           manifest->manifest_size - manifest_bytes_done);
+       rc = BufFileRead(manifest->buffile, manifestbuf, bytes_to_read);
+       if (rc != bytes_to_read)
+           ereport(ERROR,
+                   (errcode_for_file_access(),
+                    errmsg("could not read from temporary file: %m")));
+       pq_putmessage('d', manifestbuf, bytes_to_read);
+       manifest_bytes_done += bytes_to_read;
+   }
+
+   /* No more data, so send CopyDone message */
+   pq_putemptymessage('c');
+
+   /* Release resources */
+   BufFileClose(manifest->buffile);
+}
index f5b2411d5495a6a3ce7fe6ee29cc770f5d2fe820..f3fb5716a4b33f6d397ff7d80ead98e869dd1092 100644 (file)
 #include <unistd.h>
 #include <time.h>
 
-#include "access/timeline.h"
 #include "access/xlog_internal.h"  /* for pg_start/stop_backup */
 #include "catalog/pg_type.h"
-#include "common/checksum_helper.h"
 #include "common/file_perm.h"
 #include "commands/progress.h"
 #include "lib/stringinfo.h"
@@ -32,9 +30,9 @@
 #include "port.h"
 #include "postmaster/syslogger.h"
 #include "replication/basebackup.h"
+#include "replication/backup_manifest.h"
 #include "replication/walsender.h"
 #include "replication/walsender_private.h"
-#include "storage/buffile.h"
 #include "storage/bufpage.h"
 #include "storage/checksum.h"
 #include "storage/dsm_impl.h"
 #include "storage/ipc.h"
 #include "storage/reinit.h"
 #include "utils/builtins.h"
-#include "utils/json.h"
 #include "utils/ps_status.h"
 #include "utils/relcache.h"
 #include "utils/resowner.h"
 #include "utils/timestamp.h"
 
-typedef enum manifest_option
-{
-   MANIFEST_OPTION_YES,
-   MANIFEST_OPTION_NO,
-   MANIFEST_OPTION_FORCE_ENCODE
-} manifest_option;
-
 typedef struct
 {
    const char *label;
@@ -68,18 +58,6 @@ typedef struct
    pg_checksum_type manifest_checksum_type;
 } basebackup_options;
 
-struct manifest_info
-{
-   BufFile    *buffile;
-   pg_checksum_type checksum_type;
-   pg_sha256_ctx manifest_ctx;
-   uint64      manifest_size;
-   bool        force_encode;
-   bool        first_file;
-   bool        still_checksumming;
-};
-
-
 static int64 sendDir(const char *path, int basepathlen, bool sizeonly,
                     List *tablespaces, bool sendtblspclinks,
                     manifest_info *manifest, const char *spcoid);
@@ -94,18 +72,6 @@ static int64 _tarWriteDir(const char *pathbuf, int basepathlen, struct stat *sta
                          bool sizeonly);
 static void send_int8_string(StringInfoData *buf, int64 intval);
 static void SendBackupHeader(List *tablespaces);
-static bool IsManifestEnabled(manifest_info *manifest);
-static void InitializeManifest(manifest_info *manifest,
-                              basebackup_options *opt);
-static void AppendStringToManifest(manifest_info *manifest, char *s);
-static void AddFileToManifest(manifest_info *manifest, const char *spcoid,
-                             const char *pathname, size_t size,
-                             pg_time_t mtime,
-                             pg_checksum_context *checksum_ctx);
-static void AddWALInfoToManifest(manifest_info *manifest, XLogRecPtr startptr,
-                                TimeLineID starttli, XLogRecPtr endptr,
-                                TimeLineID endtli);
-static void SendBackupManifest(manifest_info *manifest);
 static void perform_base_backup(basebackup_options *opt);
 static void parse_basebackup_options(List *options, basebackup_options *opt);
 static void SendXlogRecPtrResult(XLogRecPtr ptr, TimeLineID tli);
@@ -142,16 +108,6 @@ do { \
                (errmsg("could not read from file \"%s\"", filename))); \
 } while (0)
 
-/*
- * Convenience macro for appending data to the backup manifest.
- */
-#define AppendToManifest(manifest, ...) \
-   { \
-       char *_manifest_s = psprintf(__VA_ARGS__);  \
-       AppendStringToManifest(manifest, _manifest_s);  \
-       pfree(_manifest_s); \
-   }
-
 /* The actual number of bytes, transfer of which may cause sleep. */
 static uint64 throttling_sample;
 
@@ -342,7 +298,7 @@ perform_base_backup(basebackup_options *opt)
 
    labelfile = makeStringInfo();
    tblspc_map_file = makeStringInfo();
-   InitializeManifest(&manifest, opt);
+   InitializeManifest(&manifest, opt->manifest, opt->manifest_checksum_type);
 
    total_checksum_failures = 0;
 
@@ -1068,349 +1024,6 @@ SendBackupHeader(List *tablespaces)
    pq_puttextmessage('C', "SELECT");
 }
 
-/*
- * Does the user want a backup manifest?
- *
- * It's simplest to always have a manifest_info object, so that we don't need
- * checks for NULL pointers in too many places. However, if the user doesn't
- * want a manifest, we set manifest->buffile to NULL.
- */
-static bool
-IsManifestEnabled(manifest_info *manifest)
-{
-   return (manifest->buffile != NULL);
-}
-
-/*
- * Initialize state so that we can construct a backup manifest.
- *
- * NB: Although the checksum type for the data files is configurable, the
- * checksum for the manifest itself always uses SHA-256. See comments in
- * SendBackupManifest.
- */
-static void
-InitializeManifest(manifest_info *manifest, basebackup_options *opt)
-{
-   if (opt->manifest == MANIFEST_OPTION_NO)
-       manifest->buffile = NULL;
-   else
-       manifest->buffile = BufFileCreateTemp(false);
-   manifest->checksum_type = opt->manifest_checksum_type;
-   pg_sha256_init(&manifest->manifest_ctx);
-   manifest->manifest_size = UINT64CONST(0);
-   manifest->force_encode = (opt->manifest == MANIFEST_OPTION_FORCE_ENCODE);
-   manifest->first_file = true;
-   manifest->still_checksumming = true;
-
-   if (opt->manifest != MANIFEST_OPTION_NO)
-       AppendToManifest(manifest,
-                        "{ \"PostgreSQL-Backup-Manifest-Version\": 1,\n"
-                        "\"Files\": [");
-}
-
-/*
- * Append a cstring to the manifest.
- */
-static void
-AppendStringToManifest(manifest_info *manifest, char *s)
-{
-   int         len = strlen(s);
-   size_t      written;
-
-   Assert(manifest != NULL);
-   if (manifest->still_checksumming)
-       pg_sha256_update(&manifest->manifest_ctx, (uint8 *) s, len);
-   written = BufFileWrite(manifest->buffile, s, len);
-   if (written != len)
-       ereport(ERROR,
-               (errcode_for_file_access(),
-                errmsg("could not write to temporary file: %m")));
-   manifest->manifest_size += len;
-}
-
-/*
- * Add an entry to the backup manifest for a file.
- */
-static void
-AddFileToManifest(manifest_info *manifest, const char *spcoid,
-                 const char *pathname, size_t size, pg_time_t mtime,
-                 pg_checksum_context *checksum_ctx)
-{
-   char        pathbuf[MAXPGPATH];
-   int         pathlen;
-   StringInfoData buf;
-
-   if (!IsManifestEnabled(manifest))
-       return;
-
-   /*
-    * If this file is part of a tablespace, the pathname passed to this
-    * function will be relative to the tar file that contains it. We want the
-    * pathname relative to the data directory (ignoring the intermediate
-    * symlink traversal).
-    */
-   if (spcoid != NULL)
-   {
-       snprintf(pathbuf, sizeof(pathbuf), "pg_tblspc/%s/%s", spcoid,
-                pathname);
-       pathname = pathbuf;
-   }
-
-   /*
-    * Each file's entry needs to be separated from any entry that follows by a
-    * comma, but there's no comma before the first one or after the last one.
-    * To make that work, adding a file to the manifest starts by terminating
-    * the most recently added line, with a comma if appropriate, but does not
-    * terminate the line inserted for this file.
-    */
-   initStringInfo(&buf);
-   if (manifest->first_file)
-   {
-       appendStringInfoString(&buf, "\n");
-       manifest->first_file = false;
-   }
-   else
-       appendStringInfoString(&buf, ",\n");
-
-   /*
-    * Write the relative pathname to this file out to the manifest. The
-    * manifest is always stored in UTF-8, so we have to encode paths that are
-    * not valid in that encoding.
-    */
-   pathlen = strlen(pathname);
-   if (!manifest->force_encode &&
-       pg_verify_mbstr(PG_UTF8, pathname, pathlen, true))
-   {
-       appendStringInfoString(&buf, "{ \"Path\": ");
-       escape_json(&buf, pathname);
-       appendStringInfoString(&buf, ", ");
-   }
-   else
-   {
-       appendStringInfoString(&buf, "{ \"Encoded-Path\": \"");
-       enlargeStringInfo(&buf, 2 * pathlen);
-       buf.len += hex_encode((char *) pathname, pathlen,
-                             &buf.data[buf.len]);
-       appendStringInfoString(&buf, "\", ");
-   }
-
-   appendStringInfo(&buf, "\"Size\": %zu, ", size);
-
-   /*
-    * Convert last modification time to a string and append it to the
-    * manifest. Since it's not clear what time zone to use and since time
-    * zone definitions can change, possibly causing confusion, use GMT
-    * always.
-    */
-   appendStringInfoString(&buf, "\"Last-Modified\": \"");
-   enlargeStringInfo(&buf, 128);
-   buf.len += pg_strftime(&buf.data[buf.len], 128, "%Y-%m-%d %H:%M:%S %Z",
-                          pg_gmtime(&mtime));
-   appendStringInfoString(&buf, "\"");
-
-   /* Add checksum information. */
-   if (checksum_ctx->type != CHECKSUM_TYPE_NONE)
-   {
-       uint8       checksumbuf[PG_CHECKSUM_MAX_LENGTH];
-       int         checksumlen;
-
-       checksumlen = pg_checksum_final(checksum_ctx, checksumbuf);
-
-       appendStringInfo(&buf,
-                        ", \"Checksum-Algorithm\": \"%s\", \"Checksum\": \"",
-                        pg_checksum_type_name(checksum_ctx->type));
-       enlargeStringInfo(&buf, 2 * checksumlen);
-       buf.len += hex_encode((char *) checksumbuf, checksumlen,
-                             &buf.data[buf.len]);
-       appendStringInfoString(&buf, "\"");
-   }
-
-   /* Close out the object. */
-   appendStringInfoString(&buf, " }");
-
-   /* OK, add it to the manifest. */
-   AppendStringToManifest(manifest, buf.data);
-
-   /* Avoid leaking memory. */
-   pfree(buf.data);
-}
-
-/*
- * Add information about the WAL that will need to be replayed when restoring
- * this backup to the manifest.
- */
-static void
-AddWALInfoToManifest(manifest_info *manifest, XLogRecPtr startptr,
-                    TimeLineID starttli, XLogRecPtr endptr, TimeLineID endtli)
-{
-   List       *timelines;
-   ListCell   *lc;
-   bool        first_wal_range = true;
-   bool        found_start_timeline = false;
-
-   if (!IsManifestEnabled(manifest))
-       return;
-
-   /* Terminate the list of files. */
-   AppendStringToManifest(manifest, "\n],\n");
-
-   /* Read the timeline history for the ending timeline. */
-   timelines = readTimeLineHistory(endtli);
-
-   /* Start a list of LSN ranges. */
-   AppendStringToManifest(manifest, "\"WAL-Ranges\": [\n");
-
-   foreach(lc, timelines)
-   {
-       TimeLineHistoryEntry *entry = lfirst(lc);
-       XLogRecPtr  tl_beginptr;
-
-       /*
-        * We only care about timelines that were active during the backup.
-        * Skip any that ended before the backup started. (Note that if
-        * entry->end is InvalidXLogRecPtr, it means that the timeline has not
-        * yet ended.)
-        */
-       if (!XLogRecPtrIsInvalid(entry->end) && entry->end < startptr)
-           continue;
-
-       /*
-        * Because the timeline history file lists newer timelines before
-        * older ones, the first timeline we encounter that is new enough to
-        * matter ought to match the ending timeline of the backup.
-        */
-       if (first_wal_range && endtli != entry->tli)
-           ereport(ERROR,
-                   errmsg("expected end timeline %u but found timeline %u",
-                          starttli, entry->tli));
-
-       if (!XLogRecPtrIsInvalid(entry->begin))
-           tl_beginptr = entry->begin;
-       else
-       {
-           tl_beginptr = startptr;
-
-           /*
-            * If we reach a TLI that has no valid beginning LSN, there can't
-            * be any more timelines in the history after this point, so we'd
-            * better have arrived at the expected starting TLI. If not,
-            * something's gone horribly wrong.
-            */
-           if (starttli != entry->tli)
-               ereport(ERROR,
-                       errmsg("expected start timeline %u but found timeline %u",
-                              starttli, entry->tli));
-       }
-
-       AppendToManifest(manifest,
-                        "%s{ \"Timeline\": %u, \"Start-LSN\": \"%X/%X\", \"End-LSN\": \"%X/%X\" }",
-                        first_wal_range ? "" : ",\n",
-                        entry->tli,
-                        (uint32) (tl_beginptr >> 32), (uint32) tl_beginptr,
-                        (uint32) (endptr >> 32), (uint32) endptr);
-
-       if (starttli == entry->tli)
-       {
-           found_start_timeline = true;
-           break;
-       }
-
-       endptr = entry->begin;
-       first_wal_range = false;
-   }
-
-   /*
-    * The last entry in the timeline history for the ending timeline should
-    * be the ending timeline itself. Verify that this is what we observed.
-    */
-   if (!found_start_timeline)
-       ereport(ERROR,
-               errmsg("start timeline %u not found history of timeline %u",
-                      starttli, endtli));
-
-   /* Terminate the list of WAL ranges. */
-   AppendStringToManifest(manifest, "\n],\n");
-}
-
-/*
- * Finalize the backup manifest, and send it to the client.
- */
-static void
-SendBackupManifest(manifest_info *manifest)
-{
-   StringInfoData protobuf;
-   uint8       checksumbuf[PG_SHA256_DIGEST_LENGTH];
-   char        checksumstringbuf[PG_SHA256_DIGEST_STRING_LENGTH];
-   size_t      manifest_bytes_done = 0;
-
-   if (!IsManifestEnabled(manifest))
-       return;
-
-   /*
-    * Append manifest checksum, so that the problems with the manifest itself
-    * can be detected.
-    *
-    * We always use SHA-256 for this, regardless of what algorithm is chosen
-    * for checksumming the files.  If we ever want to make the checksum
-    * algorithm used for the manifest file variable, the client will need a
-    * way to figure out which algorithm to use as close to the beginning of
-    * the manifest file as possible, to avoid having to read the whole thing
-    * twice.
-    */
-   manifest->still_checksumming = false;
-   pg_sha256_final(&manifest->manifest_ctx, checksumbuf);
-   AppendStringToManifest(manifest, "\"Manifest-Checksum\": \"");
-   hex_encode((char *) checksumbuf, sizeof checksumbuf, checksumstringbuf);
-   checksumstringbuf[PG_SHA256_DIGEST_STRING_LENGTH - 1] = '\0';
-   AppendStringToManifest(manifest, checksumstringbuf);
-   AppendStringToManifest(manifest, "\"}\n");
-
-   /*
-    * We've written all the data to the manifest file.  Rewind the file so
-    * that we can read it all back.
-    */
-   if (BufFileSeek(manifest->buffile, 0, 0L, SEEK_SET))
-       ereport(ERROR,
-               (errcode_for_file_access(),
-                errmsg("could not rewind temporary file: %m")));
-
-   /* Send CopyOutResponse message */
-   pq_beginmessage(&protobuf, 'H');
-   pq_sendbyte(&protobuf, 0);  /* overall format */
-   pq_sendint16(&protobuf, 0); /* natts */
-   pq_endmessage(&protobuf);
-
-   /*
-    * Send CopyData messages.
-    *
-    * We choose to read back the data from the temporary file in chunks of
-    * size BLCKSZ; this isn't necessary, but buffile.c uses that as the I/O
-    * size, so it seems to make sense to match that value here.
-    */
-   while (manifest_bytes_done < manifest->manifest_size)
-   {
-       char        manifestbuf[BLCKSZ];
-       size_t      bytes_to_read;
-       size_t      rc;
-
-       bytes_to_read = Min(sizeof(manifestbuf),
-                           manifest->manifest_size - manifest_bytes_done);
-       rc = BufFileRead(manifest->buffile, manifestbuf, bytes_to_read);
-       if (rc != bytes_to_read)
-           ereport(ERROR,
-                   (errcode_for_file_access(),
-                    errmsg("could not read from temporary file: %m")));
-       pq_putmessage('d', manifestbuf, bytes_to_read);
-       manifest_bytes_done += bytes_to_read;
-   }
-
-   /* No more data, so send CopyDone message */
-   pq_putemptymessage('c');
-
-   /* Release resources */
-   BufFileClose(manifest->buffile);
-}
-
 /*
  * Send a single resultset containing just a single
  * XLogRecPtr record (in text format)
diff --git a/src/include/replication/backup_manifest.h b/src/include/replication/backup_manifest.h
new file mode 100644 (file)
index 0000000..e7fccdd
--- /dev/null
@@ -0,0 +1,51 @@
+/*-------------------------------------------------------------------------
+ *
+ * backup_manifest.h
+ *   Routines for generating a backup manifest.
+ *
+ * Portions Copyright (c) 2010-2020, PostgreSQL Global Development Group
+ *
+ * src/include/replication/backup_manifest.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef BACKUP_MANIFEST_H
+#define BACKUP_MANIFEST_H
+
+#include "access/xlogdefs.h"
+#include "common/checksum_helper.h"
+#include "pgtime.h"
+#include "storage/buffile.h"
+
+typedef enum manifest_option
+{
+   MANIFEST_OPTION_YES,
+   MANIFEST_OPTION_NO,
+   MANIFEST_OPTION_FORCE_ENCODE
+} manifest_option;
+
+typedef struct manifest_info
+{
+   BufFile    *buffile;
+   pg_checksum_type checksum_type;
+   pg_sha256_ctx manifest_ctx;
+   uint64      manifest_size;
+   bool        force_encode;
+   bool        first_file;
+   bool        still_checksumming;
+} manifest_info;
+
+extern void InitializeManifest(manifest_info *manifest,
+                              manifest_option want_manifest,
+                              pg_checksum_type manifest_checksum_type);
+extern void AppendStringToManifest(manifest_info *manifest, char *s);
+extern void AddFileToManifest(manifest_info *manifest, const char *spcoid,
+                             const char *pathname, size_t size,
+                             pg_time_t mtime,
+                             pg_checksum_context *checksum_ctx);
+extern void AddWALInfoToManifest(manifest_info *manifest, XLogRecPtr startptr,
+                                TimeLineID starttli, XLogRecPtr endptr,
+                                TimeLineID endtli);
+extern void SendBackupManifest(manifest_info *manifest);
+
+#endif