pg_verifybackup.c

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/*-------------------------------------------------------------------------
 *
 * pg_verifybackup.c
 *    Verify a backup against a backup manifest.
 *
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/bin/pg_verifybackup/pg_verifybackup.c
 *
 *-------------------------------------------------------------------------
 */
 
#include "postgres_fe.h"
 
#include <dirent.h>
#include <fcntl.h>
#include <limits.h>
#include <sys/stat.h>
#include <time.h>
 
#include "access/xlog_internal.h"
#include "common/logging.h"
#include "common/parse_manifest.h"
#include "fe_utils/simple_list.h"
#include "getopt_long.h"
#include "pg_verifybackup.h"
#include "pgtime.h"
 
/*
 * For efficiency, we'd like our hash table containing information about the
 * manifest to start out with approximately the correct number of entries.
 * There's no way to know the exact number of entries without reading the whole
 * file, but we can get an estimate by dividing the file size by the estimated
 * number of bytes per line.
 *
 * This could be off by about a factor of two in either direction, because the
 * checksum algorithm has a big impact on the line lengths; e.g. a SHA512
 * checksum is 128 hex bytes, whereas a CRC-32C value is only 8, and there
 * might be no checksum at all.
 */
#define ESTIMATED_BYTES_PER_MANIFEST_LINE   100
 
/*
 * How many bytes should we try to read from a file at once?
 */
#define READ_CHUNK_SIZE             (128 * 1024)
 
/*
 * Tar file information needed for content verification.
 */
typedef struct tar_file
{
    char       *relpath;
    Oid         tblspc_oid;
    pg_compress_algorithm compress_algorithm;
} tar_file;
 
static manifest_data *parse_manifest_file(char *manifest_path);
static void verifybackup_version_cb(JsonManifestParseContext *context,
                                    int manifest_version);
static void verifybackup_system_identifier(JsonManifestParseContext *context,
                                           uint64 manifest_system_identifier);
static void verifybackup_per_file_cb(JsonManifestParseContext *context,
                                     const char *pathname, uint64 size,
                                     pg_checksum_type checksum_type,
                                     int checksum_length,
                                     uint8 *checksum_payload);
static void verifybackup_per_wal_range_cb(JsonManifestParseContext *context,
                                          TimeLineID tli,
                                          XLogRecPtr start_lsn,
                                          XLogRecPtr end_lsn);
pg_noreturn static void report_manifest_error(JsonManifestParseContext *context,
                                              const char *fmt, ...)
            pg_attribute_printf(2, 3);
 
static void verify_tar_backup(verifier_context *context, DIR *dir,
                              char **base_archive_path,
                              char **wal_archive_path);
static void verify_plain_backup_directory(verifier_context *context,
                                          char *relpath, char *fullpath,
                                          DIR *dir);
static void verify_plain_backup_file(verifier_context *context, char *relpath,
                                     char *fullpath);
static void verify_control_file(const char *controlpath,
                                uint64 manifest_system_identifier);
static void precheck_tar_backup_file(verifier_context *context, char *relpath,
                                     char *fullpath, SimplePtrList *tarfiles,
                                     char **base_archive_path,
                                     char **wal_archive_path);
static void verify_tar_file(verifier_context *context, char *relpath,
                            char *fullpath, astreamer *streamer);
static void report_extra_backup_files(verifier_context *context);
static void verify_backup_checksums(verifier_context *context);
static void verify_file_checksum(verifier_context *context,
                                 manifest_file *m, char *fullpath,
                                 uint8 *buffer);
static void parse_required_wal(verifier_context *context,
                               char *pg_waldump_path,
                               char *wal_path);
static astreamer *create_archive_verifier(verifier_context *context,
                                          char *archive_name,
                                          Oid tblspc_oid,
                                          pg_compress_algorithm compress_algo);
 
static void progress_report(bool finished);
static void usage(void);
 
static const char *progname;
 
/* is progress reporting enabled? */
static bool show_progress = false;
 
/* Progress indicators */
static uint64 total_size = 0;
static uint64 done_size = 0;
 
/*
 * Main entry point.
 */
int
main(int argc, char **argv)
{
    static struct option long_options[] = {
        {"exit-on-error", no_argument, NULL, 'e'},
        {"ignore", required_argument, NULL, 'i'},
        {"manifest-path", required_argument, NULL, 'm'},
        {"format", required_argument, NULL, 'F'},
        {"no-parse-wal", no_argument, NULL, 'n'},
        {"progress", no_argument, NULL, 'P'},
        {"quiet", no_argument, NULL, 'q'},
        {"skip-checksums", no_argument, NULL, 's'},
        {"wal-path", required_argument, NULL, 'w'},
        {"wal-directory", required_argument, NULL, 'w'},    /* deprecated */
        {NULL, 0, NULL, 0}
    };
 
    int         c;
    verifier_context context;
    char       *manifest_path = NULL;
    bool        no_parse_wal = false;
    bool        quiet = false;
    char       *wal_path = NULL;
    char       *base_archive_path = NULL;
    char       *wal_archive_path = NULL;
    char       *pg_waldump_path = NULL;
    DIR        *dir;
 
    pg_logging_init(argv[0]);
    set_pglocale_pgservice(argv[0], PG_TEXTDOMAIN("pg_verifybackup"));
    progname = get_progname(argv[0]);
 
    memset(&context, 0, sizeof(context));
 
    if (argc > 1)
    {
        if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
        {
            usage();
            exit(0);
        }
        if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
        {
            puts("pg_verifybackup (PostgreSQL) " PG_VERSION);
            exit(0);
        }
    }
 
    /*
     * Skip certain files in the toplevel directory.
     *
     * Ignore the backup_manifest file, because it's not included in the
     * backup manifest.
     *
     * Ignore the pg_wal directory, because those files are not included in
     * the backup manifest either, since they are fetched separately from the
     * backup itself, and verified via a separate mechanism.
     *
     * Ignore postgresql.auto.conf, recovery.signal, and standby.signal,
     * because we expect that those files may sometimes be created or changed
     * as part of the backup process. For example, pg_basebackup -R will
     * modify postgresql.auto.conf and create standby.signal.
     */
    simple_string_list_append(&context.ignore_list, "backup_manifest");
    simple_string_list_append(&context.ignore_list, "pg_wal");
    simple_string_list_append(&context.ignore_list, "postgresql.auto.conf");
    simple_string_list_append(&context.ignore_list, "recovery.signal");
    simple_string_list_append(&context.ignore_list, "standby.signal");
 
    while ((c = getopt_long(argc, argv, "eF:i:m:nPqsw:", long_options, NULL)) != -1)
    {
        switch (c)
        {
            case 'e':
                context.exit_on_error = true;
                break;
            case 'i':
                {
                    char       *arg = pstrdup(optarg);
 
                    canonicalize_path(arg);
                    simple_string_list_append(&context.ignore_list, arg);
                    break;
                }
            case 'm':
                manifest_path = pstrdup(optarg);
                canonicalize_path(manifest_path);
                break;
            case 'F':
                if (strcmp(optarg, "p") == 0 || strcmp(optarg, "plain") == 0)
                    context.format = 'p';
                else if (strcmp(optarg, "t") == 0 || strcmp(optarg, "tar") == 0)
                    context.format = 't';
                else
                    pg_fatal("invalid backup format \"%s\", must be \"plain\" or \"tar\"",
                             optarg);
                break;
            case 'n':
                no_parse_wal = true;
                break;
            case 'P':
                show_progress = true;
                break;
            case 'q':
                quiet = true;
                break;
            case 's':
                context.skip_checksums = true;
                break;
            case 'w':
                wal_path = pstrdup(optarg);
                canonicalize_path(wal_path);
                break;
            default:
                /* getopt_long already emitted a complaint */
                pg_log_error_hint("Try \"%s --help\" for more information.", progname);
                exit(1);
        }
    }
 
    /* Get backup directory name */
    if (optind >= argc)
    {
        pg_log_error("no backup directory specified");
        pg_log_error_hint("Try \"%s --help\" for more information.", progname);
        exit(1);
    }
    context.backup_directory = pstrdup(argv[optind++]);
    canonicalize_path(context.backup_directory);
 
    /* Complain if any arguments remain */
    if (optind < argc)
    {
        pg_log_error("too many command-line arguments (first is \"%s\")",
                     argv[optind]);
        pg_log_error_hint("Try \"%s --help\" for more information.", progname);
        exit(1);
    }
 
    /* Complain if the specified arguments conflict */
    if (show_progress && quiet)
        pg_fatal("cannot specify both %s and %s",
                 "-P/--progress", "-q/--quiet");
 
    /* Unless --no-parse-wal was specified, we will need pg_waldump. */
    if (!no_parse_wal)
    {
        int         ret;
 
        pg_waldump_path = pg_malloc(MAXPGPATH);
        ret = find_other_exec(argv[0], "pg_waldump",
                              "pg_waldump (PostgreSQL) " PG_VERSION "\n",
                              pg_waldump_path);
        if (ret < 0)
        {
            char        full_path[MAXPGPATH];
 
            if (find_my_exec(argv[0], full_path) < 0)
                strlcpy(full_path, progname, sizeof(full_path));
 
            if (ret == -1)
                pg_fatal("program \"%s\" is needed by %s but was not found in the same directory as \"%s\"",
                         "pg_waldump", "pg_verifybackup", full_path);
            else
                pg_fatal("program \"%s\" was found by \"%s\" but was not the same version as %s",
                         "pg_waldump", full_path, "pg_verifybackup");
        }
    }
 
    /* By default, look for the manifest in the backup directory. */
    if (manifest_path == NULL)
        manifest_path = psprintf("%s/backup_manifest",
                                 context.backup_directory);
 
    /*
     * Try to read the manifest. We treat any errors encountered while parsing
     * the manifest as fatal; there doesn't seem to be much point in trying to
     * verify the backup directory against a corrupted manifest.
     */
    context.manifest = parse_manifest_file(manifest_path);
 
    /*
     * If the backup directory cannot be found, treat this as a fatal error.
     */
    dir = opendir(context.backup_directory);
    if (dir == NULL)
        report_fatal_error("could not open directory \"%s\": %m",
                           context.backup_directory);
 
    /*
     * At this point, we know that the backup directory exists, so it's now
     * reasonable to check for files immediately inside it. Thus, before going
     * further, if the user did not specify the backup format, check for
     * PG_VERSION to distinguish between tar and plain format.
     */
    if (context.format == '\0')
    {
        struct stat sb;
        char       *path;
 
        path = psprintf("%s/%s", context.backup_directory, "PG_VERSION");
        if (stat(path, &sb) == 0)
            context.format = 'p';
        else if (errno != ENOENT)
        {
            pg_log_error("could not stat file \"%s\": %m", path);
            exit(1);
        }
        else
        {
            /* No PG_VERSION, so assume tar format. */
            context.format = 't';
        }
        pfree(path);
    }
 
    /*
     * Perform the appropriate type of verification appropriate based on the
     * backup format. This will close 'dir'.
     */
    if (context.format == 'p')
        verify_plain_backup_directory(&context, NULL, context.backup_directory,
                                      dir);
    else
        verify_tar_backup(&context, dir, &base_archive_path, &wal_archive_path);
 
    /*
     * The "matched" flag should now be set on every entry in the hash table.
     * Any entries for which the bit is not set are files mentioned in the
     * manifest that don't exist on disk (or in the relevant tar files).
     */
    report_extra_backup_files(&context);
 
    /*
     * If this is a tar-format backup, checksums were already verified above;
     * but if it's a plain-format backup, we postpone it until this point,
     * since the earlier checks can be performed just by knowing which files
     * are present, without needing to read all of them.
     */
    if (context.format == 'p' && !context.skip_checksums)
        verify_backup_checksums(&context);
 
    /*
     * By default, WAL files are expected to be found in the backup directory
     * for plain-format backups. In the case of tar-format backups, if a
     * separate WAL archive is not found, the WAL files are most likely
     * included within the main data directory archive.
     */
    if (wal_path == NULL)
    {
        if (context.format == 'p')
            wal_path = psprintf("%s/pg_wal", context.backup_directory);
        else if (wal_archive_path)
            wal_path = wal_archive_path;
        else if (base_archive_path)
            wal_path = base_archive_path;
        else
        {
            pg_log_error("WAL archive not found");
            pg_log_error_hint("Specify the correct path using the option -w/--wal-path.  "
                              "Or you must use -n/--no-parse-wal when verifying a tar-format backup.");
            exit(1);
        }
    }
 
    /*
     * Try to parse the required ranges of WAL records, unless we were told
     * not to do so.
     */
    if (!no_parse_wal)
        parse_required_wal(&context, pg_waldump_path, wal_path);
 
    /*
     * If everything looks OK, tell the user this, unless we were asked to
     * work quietly.
     */
    if (!context.saw_any_error && !quiet)
        printf(_("backup successfully verified\n"));
 
    return context.saw_any_error ? 1 : 0;
}
 
/*
 * Parse a manifest file and return a data structure describing the contents.
 */
static manifest_data *
parse_manifest_file(char *manifest_path)
{
    int         fd;
    struct stat statbuf;
    off_t       estimate;
    uint32      initial_size;
    manifest_files_hash *ht;
    char       *buffer;
    JsonManifestParseContext context;
    manifest_data *result;
    size_t      total_size;
    const size_t chunk_size = READ_CHUNK_SIZE;
 
    /* Open the manifest file. */
    if ((fd = open(manifest_path, O_RDONLY | PG_BINARY, 0)) < 0)
        report_fatal_error("could not open file \"%s\": %m", manifest_path);
 
    /* Figure out how big the manifest is. */
    if (fstat(fd, &statbuf) != 0)
        report_fatal_error("could not stat file \"%s\": %m", manifest_path);
 
    /* Guess how large to make the hash table based on the manifest size. */
    estimate = statbuf.st_size / ESTIMATED_BYTES_PER_MANIFEST_LINE;
    initial_size = Min(PG_UINT32_MAX, Max(estimate, 256));
 
    /* Create the hash table. */
    ht = manifest_files_create(initial_size, NULL);
 
    result = pg_malloc0_object(manifest_data);
    result->files = ht;
    context.private_data = result;
    context.version_cb = verifybackup_version_cb;
    context.system_identifier_cb = verifybackup_system_identifier;
    context.per_file_cb = verifybackup_per_file_cb;
    context.per_wal_range_cb = verifybackup_per_wal_range_cb;
    context.error_cb = report_manifest_error;
 
    total_size = statbuf.st_size;
 
    /*
     * Parse the file, in chunks if necessary.
     */
    if (total_size <= chunk_size)
    {
        ssize_t     rc;
 
        buffer = pg_malloc(total_size);
        rc = read(fd, buffer, total_size);
        if (rc != total_size)
        {
            if (rc < 0)
                pg_fatal("could not read file \"%s\": %m", manifest_path);
            else
                pg_fatal("could not read file \"%s\": read %zd of %zu",
                         manifest_path, rc, total_size);
        }
 
        /* Close the manifest file. */
        close(fd);
 
        /* Parse the manifest. */
        json_parse_manifest(&context, buffer, total_size);
    }
    else
    {
        size_t      bytes_left = total_size;
        JsonManifestParseIncrementalState *inc_state;
 
        inc_state = json_parse_manifest_incremental_init(&context);
 
        buffer = pg_malloc(chunk_size + 1);
 
        while (bytes_left > 0)
        {
            ssize_t     rc;
            size_t      bytes_to_read = chunk_size;
 
            /*
             * Make sure that the last chunk is sufficiently large. (i.e. at
             * least half the chunk size) so that it will contain fully the
             * piece at the end with the checksum.
             */
            if (bytes_left < chunk_size)
                bytes_to_read = bytes_left;
            else if (bytes_left < 2 * chunk_size)
                bytes_to_read = bytes_left / 2;
            rc = read(fd, buffer, bytes_to_read);
            if (rc != bytes_to_read)
            {
                if (rc < 0)
                    pg_fatal("could not read file \"%s\": %m", manifest_path);
                else
                    pg_fatal("could not read file \"%s\": read %zu of %zu",
                             manifest_path,
                             total_size + rc - bytes_left,
                             total_size);
            }
            bytes_left -= rc;
            json_parse_manifest_incremental_chunk(inc_state, buffer, rc,
                                                  bytes_left == 0);
        }
 
        /* Release the incremental state memory */
        json_parse_manifest_incremental_shutdown(inc_state);
 
        close(fd);
    }
 
    /* Done with the buffer. */
    pg_free(buffer);
 
    return result;
}
 
/*
 * Report an error while parsing the manifest.
 *
 * We consider all such errors to be fatal errors. The manifest parser
 * expects this function not to return.
 */
static void
report_manifest_error(JsonManifestParseContext *context, const char *fmt, ...)
{
    va_list     ap;
 
    va_start(ap, fmt);
    pg_log_generic_v(PG_LOG_ERROR, PG_LOG_PRIMARY, gettext(fmt), ap);
    va_end(ap);
 
    exit(1);
}
 
/*
 * Record details extracted from the backup manifest.
 */
static void
verifybackup_version_cb(JsonManifestParseContext *context,
                        int manifest_version)
{
    manifest_data *manifest = context->private_data;
 
    /* Validation will be at the later stage */
    manifest->version = manifest_version;
}
 
/*
 * Record details extracted from the backup manifest.
 */
static void
verifybackup_system_identifier(JsonManifestParseContext *context,
                               uint64 manifest_system_identifier)
{
    manifest_data *manifest = context->private_data;
 
    /* Validation will be at the later stage */
    manifest->system_identifier = manifest_system_identifier;
}
 
/*
 * Record details extracted from the backup manifest for one file.
 */
static void
verifybackup_per_file_cb(JsonManifestParseContext *context,
                         const char *pathname, uint64 size,
                         pg_checksum_type checksum_type,
                         int checksum_length, uint8 *checksum_payload)
{
    manifest_data *manifest = context->private_data;
    manifest_files_hash *ht = manifest->files;
    manifest_file *m;
    bool        found;
 
    /* Make a new entry in the hash table for this file. */
    m = manifest_files_insert(ht, pathname, &found);
    if (found)
        report_fatal_error("duplicate path name in backup manifest: \"%s\"",
                           pathname);
 
    /* Initialize the entry. */
    m->size = size;
    m->checksum_type = checksum_type;
    m->checksum_length = checksum_length;
    m->checksum_payload = checksum_payload;
    m->matched = false;
    m->bad = false;
}
 
/*
 * Record details extracted from the backup manifest for one WAL range.
 */
static void
verifybackup_per_wal_range_cb(JsonManifestParseContext *context,
                              TimeLineID tli,
                              XLogRecPtr start_lsn, XLogRecPtr end_lsn)
{
    manifest_data *manifest = context->private_data;
    manifest_wal_range *range;
 
    /* Allocate and initialize a struct describing this WAL range. */
    range = palloc_object(manifest_wal_range);
    range->tli = tli;
    range->start_lsn = start_lsn;
    range->end_lsn = end_lsn;
    range->prev = manifest->last_wal_range;
    range->next = NULL;
 
    /* Add it to the end of the list. */
    if (manifest->first_wal_range == NULL)
        manifest->first_wal_range = range;
    else
        manifest->last_wal_range->next = range;
    manifest->last_wal_range = range;
}
 
/*
 * Verify one directory of a plain-format backup.
 *
 * 'relpath' is NULL if we are to verify the top-level backup directory,
 * and otherwise the relative path to the directory that is to be verified.
 *
 * 'fullpath' is the backup directory with 'relpath' appended; i.e. the actual
 * filesystem path at which it can be found.
 *
 * 'dir' is an open directory handle, or NULL if the caller wants us to
 * open it. If the caller chooses to pass a handle, we'll close it when
 * we're done with it.
 */
static void
verify_plain_backup_directory(verifier_context *context, char *relpath,
                              char *fullpath, DIR *dir)
{
    struct dirent *dirent;
 
    /* Open the directory unless the caller did it. */
    if (dir == NULL && ((dir = opendir(fullpath)) == NULL))
    {
        report_backup_error(context,
                            "could not open directory \"%s\": %m", fullpath);
        simple_string_list_append(&context->ignore_list, relpath);
 
        return;
    }
 
    while (errno = 0, (dirent = readdir(dir)) != NULL)
    {
        char       *filename = dirent->d_name;
        char       *newfullpath = psprintf("%s/%s", fullpath, filename);
        char       *newrelpath;
 
        /* Skip "." and ".." */
        if (filename[0] == '.' && (filename[1] == '\0'
                                   || strcmp(filename, "..") == 0))
            continue;
 
        if (relpath == NULL)
            newrelpath = pstrdup(filename);
        else
            newrelpath = psprintf("%s/%s", relpath, filename);
 
        if (!should_ignore_relpath(context, newrelpath))
            verify_plain_backup_file(context, newrelpath, newfullpath);
 
        pfree(newfullpath);
        pfree(newrelpath);
    }
 
    if (closedir(dir))
    {
        report_backup_error(context,
                            "could not close directory \"%s\": %m", fullpath);
        return;
    }
}
 
/*
 * Verify one file (which might actually be a directory or a symlink).
 *
 * The arguments to this function have the same meaning as the similarly named
 * arguments to verify_plain_backup_directory.
 */
static void
verify_plain_backup_file(verifier_context *context, char *relpath,
                         char *fullpath)
{
    struct stat sb;
    manifest_file *m;
 
    if (stat(fullpath, &sb) != 0)
    {
        report_backup_error(context,
                            "could not stat file or directory \"%s\": %m",
                            relpath);
 
        /*
         * Suppress further errors related to this path name and, if it's a
         * directory, anything underneath it.
         */
        simple_string_list_append(&context->ignore_list, relpath);
 
        return;
    }
 
    /* If it's a directory, just recurse. */
    if (S_ISDIR(sb.st_mode))
    {
        verify_plain_backup_directory(context, relpath, fullpath, NULL);
        return;
    }
 
    /* If it's not a directory, it should be a regular file. */
    if (!S_ISREG(sb.st_mode))
    {
        report_backup_error(context,
                            "\"%s\" is not a regular file or directory",
                            relpath);
        return;
    }
 
    /* Check whether there's an entry in the manifest hash. */
    m = manifest_files_lookup(context->manifest->files, relpath);
    if (m == NULL)
    {
        report_backup_error(context,
                            "\"%s\" is present on disk but not in the manifest",
                            relpath);
        return;
    }
 
    /* Flag this entry as having been encountered in the filesystem. */
    m->matched = true;
 
    /* Check that the size matches. */
    if (m->size != sb.st_size)
    {
        report_backup_error(context,
                            "\"%s\" has size %lld on disk but size %" PRIu64 " in the manifest",
                            relpath, (long long) sb.st_size,
                            m->size);
        m->bad = true;
    }
 
    /*
     * Validate the manifest system identifier, not available in manifest
     * version 1.
     */
    if (context->manifest->version != 1 &&
        strcmp(relpath, XLOG_CONTROL_FILE) == 0)
        verify_control_file(fullpath, context->manifest->system_identifier);
 
    /* Update statistics for progress report, if necessary */
    if (show_progress && !context->skip_checksums &&
        should_verify_checksum(m))
        total_size += m->size;
 
    /*
     * We don't verify checksums at this stage. We first finish verifying that
     * we have the expected set of files with the expected sizes, and only
     * afterwards verify the checksums. That's because computing checksums may
     * take a while, and we'd like to report more obvious problems quickly.
     */
}
 
/*
 * Sanity check control file and validate system identifier against manifest
 * system identifier.
 */
static void
verify_control_file(const char *controlpath, uint64 manifest_system_identifier)
{
    ControlFileData *control_file;
    bool        crc_ok;
 
    pg_log_debug("reading \"%s\"", controlpath);
    control_file = get_controlfile_by_exact_path(controlpath, &crc_ok);
 
    /* Control file contents not meaningful if CRC is bad. */
    if (!crc_ok)
        report_fatal_error("%s: CRC is incorrect", controlpath);
 
    /* Can't interpret control file if not current version. */
    if (control_file->pg_control_version != PG_CONTROL_VERSION)
        report_fatal_error("%s: unexpected control file version",
                           controlpath);
 
    /* System identifiers should match. */
    if (manifest_system_identifier != control_file->system_identifier)
        report_fatal_error("%s: manifest system identifier is %" PRIu64 ", but control file has %" PRIu64,
                           controlpath,
                           manifest_system_identifier,
                           control_file->system_identifier);
 
    /* Release memory. */
    pfree(control_file);
}
 
/*
 * Verify tar backup.
 *
 * The caller should pass a handle to the target directory, which we will
 * close when we're done with it.
 */
static void
verify_tar_backup(verifier_context *context, DIR *dir, char **base_archive_path,
                  char **wal_archive_path)
{
    struct dirent *dirent;
    SimplePtrList tarfiles = {NULL, NULL};
    SimplePtrListCell *cell;
 
    Assert(context->format != 'p');
 
    progress_report(false);
 
    /* First pass: scan the directory for tar files. */
    while (errno = 0, (dirent = readdir(dir)) != NULL)
    {
        char       *filename = dirent->d_name;
 
        /* Skip "." and ".." */
        if (filename[0] == '.' && (filename[1] == '\0'
                                   || strcmp(filename, "..") == 0))
            continue;
 
        /*
         * Unless it's something we should ignore, perform prechecks and add
         * it to the list.
         */
        if (!should_ignore_relpath(context, filename))
        {
            char       *fullpath;
 
            fullpath = psprintf("%s/%s", context->backup_directory, filename);
            precheck_tar_backup_file(context, filename, fullpath, &tarfiles,
                                     base_archive_path, wal_archive_path);
            pfree(fullpath);
        }
    }
 
    if (closedir(dir))
    {
        report_backup_error(context,
                            "could not close directory \"%s\": %m",
                            context->backup_directory);
        return;
    }
 
    /* Second pass: Perform the final verification of the tar contents. */
    for (cell = tarfiles.head; cell != NULL; cell = cell->next)
    {
        tar_file   *tar = (tar_file *) cell->ptr;
        astreamer  *streamer;
        char       *fullpath;
 
        /*
         * Prepares the archive streamer stack according to the tar
         * compression format.
         */
        streamer = create_archive_verifier(context,
                                           tar->relpath,
                                           tar->tblspc_oid,
                                           tar->compress_algorithm);
 
        /* Compute the full pathname to the target file. */
        fullpath = psprintf("%s/%s", context->backup_directory,
                            tar->relpath);
 
        /* Invoke the streamer for reading, decompressing, and verifying. */
        verify_tar_file(context, tar->relpath, fullpath, streamer);
 
        /* Cleanup. */
        pfree(tar->relpath);
        pfree(tar);
        pfree(fullpath);
 
        astreamer_finalize(streamer);
        astreamer_free(streamer);
    }
    simple_ptr_list_destroy(&tarfiles);
 
    progress_report(true);
}
 
/*
 * Preparatory steps for verifying files in tar format backups.
 *
 * Carries out basic validation of the tar format backup file, detects the
 * compression type, and appends that information to the tarfiles list. An
 * error will be reported if the tar file is inaccessible, or if the file type,
 * name, or compression type is not as expected.
 *
 * The arguments to this function are mostly the same as the
 * verify_plain_backup_file. The additional argument outputs a list of valid
 * tar files, along with the full paths to the main archive and the WAL
 * directory archive.
 */
static void
precheck_tar_backup_file(verifier_context *context, char *relpath,
                         char *fullpath, SimplePtrList *tarfiles,
                         char **base_archive_path, char **wal_archive_path)
{
    struct stat sb;
    Oid         tblspc_oid = InvalidOid;
    pg_compress_algorithm compress_algorithm;
    tar_file   *tar;
    char       *suffix = NULL;
    bool        is_base_archive = false;
    bool        is_wal_archive = false;
 
    /* Should be tar format backup */
    Assert(context->format == 't');
 
    /* Get file information */
    if (stat(fullpath, &sb) != 0)
    {
        report_backup_error(context,
                            "could not stat file or directory \"%s\": %m",
                            relpath);
        return;
    }
 
    /* In a tar format backup, we expect only regular files. */
    if (!S_ISREG(sb.st_mode))
    {
        report_backup_error(context,
                            "file \"%s\" is not a regular file",
                            relpath);
        return;
    }
 
    /*
     * We expect tar files for backing up the main directory, tablespace, and
     * pg_wal directory.
     *
     * pg_basebackup writes the main data directory to an archive file named
     * base.tar, the pg_wal directory to pg_wal.tar, and the tablespace
     * directory to <tablespaceoid>.tar, each followed by a compression type
     * extension such as .gz, .lz4, or .zst.
     */
    if (strncmp("base", relpath, 4) == 0)
    {
        suffix = relpath + 4;
        is_base_archive = true;
    }
    else if (strncmp("pg_wal", relpath, 6) == 0)
    {
        suffix = relpath + 6;
        is_wal_archive = true;
    }
    else
    {
        /* Expected a <tablespaceoid>.tar file here. */
        uint64      num = strtoul(relpath, &suffix, 10);
 
        /*
         * Report an error if we didn't consume at least one character, if the
         * result is 0, or if the value is too large to be a valid OID.
         */
        if (suffix == NULL || num <= 0 || num > OID_MAX)
        {
            report_backup_error(context,
                                "file \"%s\" is not expected in a tar format backup",
                                relpath);
            return;
        }
        tblspc_oid = (Oid) num;
    }
 
    /* Now, check the compression type of the tar */
    if (!parse_tar_compress_algorithm(suffix, &compress_algorithm))
    {
        report_backup_error(context,
                            "file \"%s\" is not expected in a tar format backup",
                            relpath);
        return;
    }
 
    /*
     * Ignore WALs, as reading and verification will be handled through
     * pg_waldump.
     */
    if (is_wal_archive)
    {
        *wal_archive_path = pstrdup(fullpath);
        return;
    }
    else if (is_base_archive)
        *base_archive_path = pstrdup(fullpath);
 
    /*
     * Append the information to the list for complete verification at a later
     * stage.
     */
    tar = pg_malloc_object(tar_file);
    tar->relpath = pstrdup(relpath);
    tar->tblspc_oid = tblspc_oid;
    tar->compress_algorithm = compress_algorithm;
 
    simple_ptr_list_append(tarfiles, tar);
 
    /* Update statistics for progress report, if necessary */
    if (show_progress)
        total_size += sb.st_size;
}
 
/*
 * Verification of a single tar file content.
 *
 * It reads a given tar archive in predefined chunks and passes it to the
 * streamer, which initiates routines for decompression (if necessary) and then
 * verifies each member within the tar file.
 */
static void
verify_tar_file(verifier_context *context, char *relpath, char *fullpath,
                astreamer *streamer)
{
    int         fd;
    ssize_t     rc;
    char       *buffer;
 
    pg_log_debug("reading \"%s\"", fullpath);
 
    /* Open the target file. */
    if ((fd = open(fullpath, O_RDONLY | PG_BINARY, 0)) < 0)
    {
        report_backup_error(context, "could not open file \"%s\": %m",
                            relpath);
        return;
    }
 
    buffer = pg_malloc(READ_CHUNK_SIZE * sizeof(uint8));
 
    /* Perform the reads */
    while ((rc = read(fd, buffer, READ_CHUNK_SIZE)) > 0)
    {
        astreamer_content(streamer, NULL, buffer, rc, ASTREAMER_UNKNOWN);
 
        /* Report progress */
        done_size += rc;
        progress_report(false);
    }
 
    pg_free(buffer);
 
    if (rc < 0)
        report_backup_error(context, "could not read file \"%s\": %m",
                            relpath);
 
    /* Close the file. */
    if (close(fd) != 0)
        report_backup_error(context, "could not close file \"%s\": %m",
                            relpath);
}
 
/*
 * Scan the hash table for entries where the 'matched' flag is not set; report
 * that such files are present in the manifest but not on disk.
 */
static void
report_extra_backup_files(verifier_context *context)
{
    manifest_data *manifest = context->manifest;
    manifest_files_iterator it;
    manifest_file *m;
 
    manifest_files_start_iterate(manifest->files, &it);
    while ((m = manifest_files_iterate(manifest->files, &it)) != NULL)
        if (!m->matched && !should_ignore_relpath(context, m->pathname))
            report_backup_error(context,
                                "\"%s\" is present in the manifest but not on disk",
                                m->pathname);
}
 
/*
 * Verify checksums for hash table entries that are otherwise unproblematic.
 * If we've already reported some problem related to a hash table entry, or
 * if it has no checksum, just skip it.
 */
static void
verify_backup_checksums(verifier_context *context)
{
    manifest_data *manifest = context->manifest;
    manifest_files_iterator it;
    manifest_file *m;
    uint8      *buffer;
 
    progress_report(false);
 
    buffer = pg_malloc_array(uint8, READ_CHUNK_SIZE);
 
    manifest_files_start_iterate(manifest->files, &it);
    while ((m = manifest_files_iterate(manifest->files, &it)) != NULL)
    {
        if (should_verify_checksum(m) &&
            !should_ignore_relpath(context, m->pathname))
        {
            char       *fullpath;
 
            /* Compute the full pathname to the target file. */
            fullpath = psprintf("%s/%s", context->backup_directory,
                                m->pathname);
 
            /* Do the actual checksum verification. */
            verify_file_checksum(context, m, fullpath, buffer);
 
            /* Avoid leaking memory. */
            pfree(fullpath);
        }
    }
 
    pg_free(buffer);
 
    progress_report(true);
}
 
/*
 * Verify the checksum of a single file.
 */
static void
verify_file_checksum(verifier_context *context, manifest_file *m,
                     char *fullpath, uint8 *buffer)
{
    pg_checksum_context checksum_ctx;
    const char *relpath = m->pathname;
    int         fd;
    ssize_t     rc;
    uint64      bytes_read = 0;
    uint8       checksumbuf[PG_CHECKSUM_MAX_LENGTH];
    int         checksumlen;
 
    /* Open the target file. */
    if ((fd = open(fullpath, O_RDONLY | PG_BINARY, 0)) < 0)
    {
        report_backup_error(context, "could not open file \"%s\": %m",
                            relpath);
        return;
    }
 
    /* Initialize checksum context. */
    if (pg_checksum_init(&checksum_ctx, m->checksum_type) < 0)
    {
        report_backup_error(context, "could not initialize checksum of file \"%s\"",
                            relpath);
        close(fd);
        return;
    }
 
    /* Read the file chunk by chunk, updating the checksum as we go. */
    while ((rc = read(fd, buffer, READ_CHUNK_SIZE)) > 0)
    {
        bytes_read += rc;
        if (pg_checksum_update(&checksum_ctx, buffer, rc) < 0)
        {
            report_backup_error(context, "could not update checksum of file \"%s\"",
                                relpath);
            close(fd);
            return;
        }
 
        /* Report progress */
        done_size += rc;
        progress_report(false);
    }
    if (rc < 0)
        report_backup_error(context, "could not read file \"%s\": %m",
                            relpath);
 
    /* Close the file. */
    if (close(fd) != 0)
    {
        report_backup_error(context, "could not close file \"%s\": %m",
                            relpath);
        return;
    }
 
    /* If we didn't manage to read the whole file, bail out now. */
    if (rc < 0)
        return;
 
    /*
     * Double-check that we read the expected number of bytes from the file.
     * Normally, mismatches would be caught in verify_plain_backup_file and
     * this check would never be reached, but this provides additional safety
     * and clarity in the event of concurrent modifications or filesystem
     * misbehavior.
     */
    if (bytes_read != m->size)
    {
        report_backup_error(context,
                            "file \"%s\" should contain %" PRIu64 " bytes, but read %" PRIu64,
                            relpath, m->size, bytes_read);
        return;
    }
 
    /* Get the final checksum. */
    checksumlen = pg_checksum_final(&checksum_ctx, checksumbuf);
    if (checksumlen < 0)
    {
        report_backup_error(context,
                            "could not finalize checksum of file \"%s\"",
                            relpath);
        return;
    }
 
    /* And check it against the manifest. */
    if (checksumlen != m->checksum_length)
        report_backup_error(context,
                            "file \"%s\" has checksum of length %d, but expected %d",
                            relpath, m->checksum_length, checksumlen);
    else if (memcmp(checksumbuf, m->checksum_payload, checksumlen) != 0)
        report_backup_error(context,
                            "checksum mismatch for file \"%s\"",
                            relpath);
}
 
/*
 * Attempt to parse the WAL files required to restore from backup using
 * pg_waldump.
 */
static void
parse_required_wal(verifier_context *context, char *pg_waldump_path,
                   char *wal_path)
{
    manifest_data *manifest = context->manifest;
    manifest_wal_range *this_wal_range = manifest->first_wal_range;
 
    while (this_wal_range != NULL)
    {
        char       *pg_waldump_cmd;
 
        pg_waldump_cmd = psprintf("\"%s\" --quiet --path=\"%s\" --timeline=%u --start=%X/%08X --end=%X/%08X\n",
                                  pg_waldump_path, wal_path, this_wal_range->tli,
                                  LSN_FORMAT_ARGS(this_wal_range->start_lsn),
                                  LSN_FORMAT_ARGS(this_wal_range->end_lsn));
        fflush(NULL);
        if (system(pg_waldump_cmd) != 0)
            report_backup_error(context,
                                "WAL parsing failed for timeline %u",
                                this_wal_range->tli);
 
        this_wal_range = this_wal_range->next;
    }
}
 
/*
 * Report a problem with the backup.
 *
 * Update the context to indicate that we saw an error, and exit if the
 * context says we should.
 */
void
report_backup_error(verifier_context *context, const char *pg_restrict fmt, ...)
{
    va_list     ap;
 
    va_start(ap, fmt);
    pg_log_generic_v(PG_LOG_ERROR, PG_LOG_PRIMARY, gettext(fmt), ap);
    va_end(ap);
 
    context->saw_any_error = true;
    if (context->exit_on_error)
        exit(1);
}
 
/*
 * Report a fatal error and exit
 */
void
report_fatal_error(const char *pg_restrict fmt, ...)
{
    va_list     ap;
 
    va_start(ap, fmt);
    pg_log_generic_v(PG_LOG_ERROR, PG_LOG_PRIMARY, gettext(fmt), ap);
    va_end(ap);
 
    exit(1);
}
 
/*
 * Is the specified relative path, or some prefix of it, listed in the set
 * of paths to ignore?
 *
 * Note that by "prefix" we mean a parent directory; for this purpose,
 * "aa/bb" is not a prefix of "aa/bbb", but it is a prefix of "aa/bb/cc".
 */
bool
should_ignore_relpath(verifier_context *context, const char *relpath)
{
    SimpleStringListCell *cell;
 
    for (cell = context->ignore_list.head; cell != NULL; cell = cell->next)
    {
        const char *r = relpath;
        char       *v = cell->val;
 
        while (*v != '\0' && *r == *v)
            ++r, ++v;
 
        if (*v == '\0' && (*r == '\0' || *r == '/'))
            return true;
    }
 
    return false;
}
 
/*
 * Create a chain of archive streamers appropriate for verifying a given
 * archive.
 */
static astreamer *
create_archive_verifier(verifier_context *context, char *archive_name,
                        Oid tblspc_oid, pg_compress_algorithm compress_algo)
{
    astreamer  *streamer = NULL;
 
    /* Should be here only for tar backup */
    Assert(context->format == 't');
 
    /* Last step is the actual verification. */
    streamer = astreamer_verify_content_new(streamer, context, archive_name,
                                            tblspc_oid);
 
    /* Before that we must parse the tar file. */
    streamer = astreamer_tar_parser_new(streamer);
 
    /* Before that we must decompress, if archive is compressed. */
    if (compress_algo == PG_COMPRESSION_GZIP)
        streamer = astreamer_gzip_decompressor_new(streamer);
    else if (compress_algo == PG_COMPRESSION_LZ4)
        streamer = astreamer_lz4_decompressor_new(streamer);
    else if (compress_algo == PG_COMPRESSION_ZSTD)
        streamer = astreamer_zstd_decompressor_new(streamer);
 
    return streamer;
}
 
/*
 * Print a progress report based on the global variables.
 *
 * Progress report is written at maximum once per second, unless the finished
 * parameter is set to true.
 *
 * If finished is set to true, this is the last progress report. The cursor
 * is moved to the next line.
 */
static void
progress_report(bool finished)
{
    static pg_time_t last_progress_report = 0;
    pg_time_t   now;
    int         percent_size = 0;
    char        totalsize_str[32];
    char        donesize_str[32];
 
    if (!show_progress)
        return;
 
    now = time(NULL);
    if (now == last_progress_report && !finished)
        return;                 /* Max once per second */
 
    last_progress_report = now;
    percent_size = total_size ? (int) ((done_size * 100 / total_size)) : 0;
 
    snprintf(totalsize_str, sizeof(totalsize_str), UINT64_FORMAT,
             total_size / 1024);
    snprintf(donesize_str, sizeof(donesize_str), UINT64_FORMAT,
             done_size / 1024);
 
    fprintf(stderr,
            _("%*s/%s kB (%d%%) verified"),
            (int) strlen(totalsize_str),
            donesize_str, totalsize_str, percent_size);
 
    /*
     * Stay on the same line if reporting to a terminal and we're not done
     * yet.
     */
    fputc((!finished && isatty(fileno(stderr))) ? '\r' : '\n', stderr);
}
 
/*
 * Print out usage information and exit.
 */
static void
usage(void)
{
    printf(_("%s verifies a backup against the backup manifest.\n\n"), progname);
    printf(_("Usage:\n  %s [OPTION]... BACKUPDIR\n\n"), progname);
    printf(_("Options:\n"));
    printf(_("  -e, --exit-on-error         exit immediately on error\n"));
    printf(_("  -F, --format=p|t            backup format (plain, tar)\n"));
    printf(_("  -i, --ignore=RELATIVE_PATH  ignore indicated path\n"));
    printf(_("  -m, --manifest-path=PATH    use specified path for manifest\n"));
    printf(_("  -n, --no-parse-wal          do not try to parse WAL files\n"));
    printf(_("  -P, --progress              show progress information\n"));
    printf(_("  -q, --quiet                 do not print any output, except for errors\n"));
    printf(_("  -s, --skip-checksums        skip checksum verification\n"));
    printf(_("  -w, --wal-path=PATH         use specified path for WAL files\n"));
    printf(_("      --wal-directory=PATH    (same as --wal-path, deprecated)\n"));
    printf(_("  -V, --version               output version information, then exit\n"));
    printf(_("  -?, --help                  show this help, then exit\n"));
    printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
}