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/*-------------------------------------------------------------------------
*
* astreamer_inject.c
*
* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/bin/pg_basebackup/astreamer_inject.c
*-------------------------------------------------------------------------
*/
#include "postgres_fe.h"
#include "astreamer_inject.h"
#include "common/file_perm.h"
#include "common/logging.h"
typedef struct astreamer_recovery_injector
{
astreamer base;
bool skip_file;
bool is_recovery_guc_supported;
bool is_postgresql_auto_conf;
bool found_postgresql_auto_conf;
PQExpBuffer recoveryconfcontents;
astreamer_member member;
} astreamer_recovery_injector;
static void astreamer_recovery_injector_content(astreamer *streamer,
astreamer_member *member,
const char *data, int len,
astreamer_archive_context context);
static void astreamer_recovery_injector_finalize(astreamer *streamer);
static void astreamer_recovery_injector_free(astreamer *streamer);
static const astreamer_ops astreamer_recovery_injector_ops = {
.content = astreamer_recovery_injector_content,
.finalize = astreamer_recovery_injector_finalize,
.free = astreamer_recovery_injector_free
};
/*
* Create a astreamer that can edit recoverydata into an archive stream.
*
* The input should be a series of typed chunks (not ASTREAMER_UNKNOWN) as
* per the conventions described in astreamer.h; the chunks forwarded to
* the next astreamer will be similarly typed, but the
* ASTREAMER_MEMBER_HEADER chunks may be zero-length in cases where we've
* edited the archive stream.
*
* Our goal is to do one of the following three things with the content passed
* via recoveryconfcontents: (1) if is_recovery_guc_supported is false, then
* put the content into recovery.conf, replacing any existing archive member
* by that name; (2) if is_recovery_guc_supported is true and
* postgresql.auto.conf exists in the archive, then append the content
* provided to the existing file; and (3) if is_recovery_guc_supported is
* true but postgresql.auto.conf does not exist in the archive, then create
* it with the specified content.
*
* In addition, if is_recovery_guc_supported is true, then we create a
* zero-length standby.signal file, dropping any file with that name from
* the archive.
*/
astreamer *
astreamer_recovery_injector_new(astreamer *next,
bool is_recovery_guc_supported,
PQExpBuffer recoveryconfcontents)
{
astreamer_recovery_injector *streamer;
streamer = palloc0(sizeof(astreamer_recovery_injector));
*((const astreamer_ops **) &streamer->base.bbs_ops) =
&astreamer_recovery_injector_ops;
streamer->base.bbs_next = next;
streamer->is_recovery_guc_supported = is_recovery_guc_supported;
streamer->recoveryconfcontents = recoveryconfcontents;
return &streamer->base;
}
/*
* Handle each chunk of tar content while injecting recovery configuration.
*/
static void
astreamer_recovery_injector_content(astreamer *streamer,
astreamer_member *member,
const char *data, int len,
astreamer_archive_context context)
{
astreamer_recovery_injector *mystreamer;
mystreamer = (astreamer_recovery_injector *) streamer;
Assert(member != NULL || context == ASTREAMER_ARCHIVE_TRAILER);
switch (context)
{
case ASTREAMER_MEMBER_HEADER:
/* Must copy provided data so we have the option to modify it. */
memcpy(&mystreamer->member, member, sizeof(astreamer_member));
/*
* On v12+, skip standby.signal and edit postgresql.auto.conf; on
* older versions, skip recovery.conf.
*/
if (mystreamer->is_recovery_guc_supported)
{
mystreamer->skip_file =
(strcmp(member->pathname, "standby.signal") == 0);
mystreamer->is_postgresql_auto_conf =
(strcmp(member->pathname, "postgresql.auto.conf") == 0);
if (mystreamer->is_postgresql_auto_conf)
{
/* Remember we saw it so we don't add it again. */
mystreamer->found_postgresql_auto_conf = true;
/* Increment length by data to be injected. */
mystreamer->member.size +=
mystreamer->recoveryconfcontents->len;
/*
* Zap data and len because the archive header is no
* longer valid; some subsequent astreamer must regenerate
* it if it's necessary.
*/
data = NULL;
len = 0;
}
}
else
mystreamer->skip_file =
(strcmp(member->pathname, "recovery.conf") == 0);
/* Do not forward if the file is to be skipped. */
if (mystreamer->skip_file)
return;
break;
case ASTREAMER_MEMBER_CONTENTS:
/* Do not forward if the file is to be skipped. */
if (mystreamer->skip_file)
return;
break;
case ASTREAMER_MEMBER_TRAILER:
/* Do not forward it the file is to be skipped. */
if (mystreamer->skip_file)
return;
/* Append provided content to whatever we already sent. */
if (mystreamer->is_postgresql_auto_conf)
astreamer_content(mystreamer->base.bbs_next, member,
mystreamer->recoveryconfcontents->data,
mystreamer->recoveryconfcontents->len,
ASTREAMER_MEMBER_CONTENTS);
break;
case ASTREAMER_ARCHIVE_TRAILER:
if (mystreamer->is_recovery_guc_supported)
{
/*
* If we didn't already find (and thus modify)
* postgresql.auto.conf, inject it as an additional archive
* member now.
*/
if (!mystreamer->found_postgresql_auto_conf)
astreamer_inject_file(mystreamer->base.bbs_next,
"postgresql.auto.conf",
mystreamer->recoveryconfcontents->data,
mystreamer->recoveryconfcontents->len);
/* Inject empty standby.signal file. */
astreamer_inject_file(mystreamer->base.bbs_next,
"standby.signal", "", 0);
}
else
{
/* Inject recovery.conf file with specified contents. */
astreamer_inject_file(mystreamer->base.bbs_next,
"recovery.conf",
mystreamer->recoveryconfcontents->data,
mystreamer->recoveryconfcontents->len);
}
/* Nothing to do here. */
break;
default:
/* Shouldn't happen. */
pg_fatal("unexpected state while injecting recovery settings");
}
astreamer_content(mystreamer->base.bbs_next, &mystreamer->member,
data, len, context);
}
/*
* End-of-stream processing for this astreamer.
*/
static void
astreamer_recovery_injector_finalize(astreamer *streamer)
{
astreamer_finalize(streamer->bbs_next);
}
/*
* Free memory associated with this astreamer.
*/
static void
astreamer_recovery_injector_free(astreamer *streamer)
{
astreamer_free(streamer->bbs_next);
pfree(streamer);
}
/*
* Inject a member into the archive with specified contents.
*/
void
astreamer_inject_file(astreamer *streamer, char *pathname, char *data,
int len)
{
astreamer_member member;
strlcpy(member.pathname, pathname, MAXPGPATH);
member.size = len;
member.mode = pg_file_create_mode;
member.is_directory = false;
member.is_link = false;
member.linktarget[0] = '\0';
/*
* There seems to be no principled argument for these values, but they are
* what PostgreSQL has historically used.
*/
member.uid = 04000;
member.gid = 02000;
/*
* We don't know here how to generate valid member headers and trailers
* for the archiving format in use, so if those are needed, some successor
* astreamer will have to generate them using the data from 'member'.
*/
astreamer_content(streamer, &member, NULL, 0,
ASTREAMER_MEMBER_HEADER);
astreamer_content(streamer, &member, data, len,
ASTREAMER_MEMBER_CONTENTS);
astreamer_content(streamer, &member, NULL, 0,
ASTREAMER_MEMBER_TRAILER);
}
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