/*-------------------------------------------------------------------------

 *

 * shell_archive.c

 *

 * This archiving function uses a user-specified shell command (the

 * archive_command GUC) to copy write-ahead log files.  It is used as the

 * default, but other modules may define their own custom archiving logic.

 *

 * Copyright (c) 2022-2026, PostgreSQL Global Development Group

 *

 * IDENTIFICATION

 *    src/backend/archive/shell_archive.c

 *

 *-------------------------------------------------------------------------

 */

#include "postgres.h"

#include <sys/wait.h>

#include "access/xlog.h"

#include "archive/archive_module.h"

#include "archive/shell_archive.h"

#include "common/percentrepl.h"

#include "pgstat.h"

#include "utils/wait_event.h"

static bool shell_archive_configured(ArchiveModuleState *state);

static bool shell_archive_file(ArchiveModuleState *state,

                 const char *file,

                 const char *path);

static void shell_archive_shutdown(ArchiveModuleState *state);

static const ArchiveModuleCallbacks shell_archive_callbacks = {

  .startup_cb = NULL,

  .check_configured_cb = shell_archive_configured,

  .archive_file_cb = shell_archive_file,

  .shutdown_cb = shell_archive_shutdown

};

const ArchiveModuleCallbacks *

shell_archive_init(void)

{

  return &shell_archive_callbacks;

}

static bool

shell_archive_configured(ArchiveModuleState *state)

{

  if (XLogArchiveCommand[0] != '\0')

    return true;

  arch_module_check_errdetail("\"%s\" is not set.",

                "archive_command");

  return false;

}

static bool

shell_archive_file(ArchiveModuleState *state, const char *file,

           const char *path)

{

  char     *xlogarchcmd;

  char     *nativePath = NULL;

  int     rc;

  if (path)

  {

    nativePath = pstrdup(path);

    make_native_path(nativePath);

  }

  xlogarchcmd = replace_percent_placeholders(XLogArchiveCommand,

                         "archive_command", "fp",

                         file, nativePath);

  ereport(DEBUG3,

      (errmsg_internal("executing archive command \"%s\"",

               xlogarchcmd)));

  fflush(NULL);

  pgstat_report_wait_start(WAIT_EVENT_ARCHIVE_COMMAND);

  rc = system(xlogarchcmd);

  pgstat_report_wait_end();

  if (rc != 0)

  {

    /*

     * If either the shell itself, or a called command, died on a signal,

     * abort the archiver.  We do this because system() ignores SIGINT and

     * SIGQUIT while waiting; so a signal is very likely something that

     * should have interrupted us too.  Also die if the shell got a hard

     * "command not found" type of error.  If we overreact it's no big

     * deal, the postmaster will just start the archiver again.

     */

    int     lev = wait_result_is_any_signal(rc, true) ? FATAL : LOG;

    if (WIFEXITED(rc))

    {

      ereport(lev,

          (errmsg("archive command failed with exit code %d",

              WEXITSTATUS(rc)),

           errdetail("The failed archive command was: %s",

                 xlogarchcmd)));

    }

    else if (WIFSIGNALED(rc))

    {

#if defined(WIN32)

      ereport(lev,

          (errmsg("archive command was terminated by exception 0x%X",

              WTERMSIG(rc)),

           errhint("See C include file \"ntstatus.h\" for a description of the hexadecimal value."),

           errdetail("The failed archive command was: %s",

                 xlogarchcmd)));

#else

      ereport(lev,

          (errmsg("archive command was terminated by signal %d: %s",

              WTERMSIG(rc), pg_strsignal(WTERMSIG(rc))),

           errdetail("The failed archive command was: %s",

                 xlogarchcmd)));

#endif

    }

    else

    {

      ereport(lev,

          (errmsg("archive command exited with unrecognized status %d",

              rc),

           errdetail("The failed archive command was: %s",

                 xlogarchcmd)));

    }

    pfree(xlogarchcmd);

    return false;

  }

  pfree(xlogarchcmd);

  elog(DEBUG1, "archived write-ahead log file \"%s\"", file);

  return true;

}

static void

shell_archive_shutdown(ArchiveModuleState *state)

{

  elog(DEBUG1, "archiver process shutting down");

}