copy.h File Reference

#include "libpq-fe.h"

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Functions
bool	do_copy (const char *args)
bool	handleCopyOut (PGconn *conn, FILE *copystream, PGresult **res)
bool	handleCopyIn (PGconn *conn, FILE *copystream, bool isbinary, PGresult **res)

Function Documentation

do_copy()

bool do_copy

(

const char *

args

)

Definition at line 268 of file copy.c.

{
    PQExpBufferData query;
    FILE       *copystream;
    struct copy_options *options;
    bool        success;
 
    /* parse options */
    options = parse_slash_copy(args);
 
    if (!options)
        return false;
 
    /* prepare to read or write the target file */
    if (options->file && !options->program)
        canonicalize_path(options->file);
 
    if (options->from)
    {
        if (options->file)
        {
            if (options->program)
            {
                fflush(NULL);
                errno = 0;
                copystream = popen(options->file, PG_BINARY_R);
            }
            else
                copystream = fopen(options->file, PG_BINARY_R);
        }
        else if (!options->psql_inout)
            copystream = pset.cur_cmd_source;
        else
            copystream = stdin;
    }
    else
    {
        if (options->file)
        {
            if (options->program)
            {
                fflush(NULL);
                disable_sigpipe_trap();
                errno = 0;
                copystream = popen(options->file, PG_BINARY_W);
            }
            else
                copystream = fopen(options->file, PG_BINARY_W);
        }
        else if (!options->psql_inout)
            copystream = pset.queryFout;
        else
            copystream = stdout;
    }
 
    if (!copystream)
    {
        if (options->program)
            pg_log_error("could not execute command \"%s\": %m",
                         options->file);
        else
            pg_log_error("%s: %m",
                         options->file);
        free_copy_options(options);
        return false;
    }
 
    if (!options->program)
    {
        struct stat st;
        int         result;
 
        /* make sure the specified file is not a directory */
        if ((result = fstat(fileno(copystream), &st)) < 0)
            pg_log_error("could not stat file \"%s\": %m",
                         options->file);
 
        if (result == 0 && S_ISDIR(st.st_mode))
            pg_log_error("%s: cannot copy from/to a directory",
                         options->file);
 
        if (result < 0 || S_ISDIR(st.st_mode))
        {
            fclose(copystream);
            free_copy_options(options);
            return false;
        }
    }
 
    /* build the command we will send to the backend */
    initPQExpBuffer(&query);
    printfPQExpBuffer(&query, "COPY ");
    appendPQExpBufferStr(&query, options->before_tofrom);
    if (options->from)
        appendPQExpBufferStr(&query, " FROM STDIN ");
    else
        appendPQExpBufferStr(&query, " TO STDOUT ");
    if (options->after_tofrom)
        appendPQExpBufferStr(&query, options->after_tofrom);
 
    /* run it like a user command, but with copystream as data source/sink */
    pset.copyStream = copystream;
    success = SendQuery(query.data);
    pset.copyStream = NULL;
    termPQExpBuffer(&query);
 
    if (options->file != NULL)
    {
        if (options->program)
        {
            int         pclose_rc = pclose(copystream);
 
            if (pclose_rc != 0)
            {
                if (pclose_rc < 0)
                    pg_log_error("could not close pipe to external command: %m");
                else
                {
                    char       *reason = wait_result_to_str(pclose_rc);
 
                    pg_log_error("%s: %s", options->file,
                                 reason ? reason : "");
                    free(reason);
                }
                success = false;
            }
            SetShellResultVariables(pclose_rc);
            restore_sigpipe_trap();
        }
        else
        {
            if (fclose(copystream) != 0)
            {
                pg_log_error("%s: %m", options->file);
                success = false;
            }
        }
    }
    free_copy_options(options);
    return success;
}

References appendPQExpBufferStr(), generate_unaccent_rules::args, canonicalize_path(), _psqlSettings::copyStream, _psqlSettings::cur_cmd_source, PQExpBufferData::data, disable_sigpipe_trap(), fflush(), free, free_copy_options(), fstat, initPQExpBuffer(), options, parse_slash_copy(), PG_BINARY_R, PG_BINARY_W, pg_log_error, printfPQExpBuffer(), pset, _psqlSettings::queryFout, restore_sigpipe_trap(), S_ISDIR, SendQuery(), SetShellResultVariables(), stat::st_mode, generate_unaccent_rules::stdout, success, termPQExpBuffer(), and wait_result_to_str().

Referenced by exec_command_copy().

handleCopyIn()

bool handleCopyIn	(	PGconn *	conn,
		FILE *	copystream,
		bool	isbinary,
		PGresult **	res
	)

Definition at line 511 of file copy.c.

{
    bool        OK;
    char        buf[COPYBUFSIZ];
    bool        showprompt;
 
    /*
     * Establish longjmp destination for exiting from wait-for-input. (This is
     * only effective while sigint_interrupt_enabled is TRUE.)
     */
    if (sigsetjmp(sigint_interrupt_jmp, 1) != 0)
    {
        /* got here with longjmp */
 
        /* Terminate data transfer */
        PQputCopyEnd(conn,
                     (PQprotocolVersion(conn) < 3) ? NULL :
                     _("canceled by user"));
 
        OK = false;
        goto copyin_cleanup;
    }
 
    /* Prompt if interactive input */
    if (isatty(fileno(copystream)))
    {
        showprompt = true;
        if (!pset.quiet)
            puts(_("Enter data to be copied followed by a newline.\n"
                   "End with a backslash and a period on a line by itself, or an EOF signal."));
    }
    else
        showprompt = false;
 
    OK = true;
 
    if (isbinary)
    {
        /* interactive input probably silly, but give one prompt anyway */
        if (showprompt)
        {
            const char *prompt = get_prompt(PROMPT_COPY, NULL);
 
            fputs(prompt, stdout);
            fflush(stdout);
        }
 
        for (;;)
        {
            int         buflen;
 
            /* enable longjmp while waiting for input */
            sigint_interrupt_enabled = true;
 
            buflen = fread(buf, 1, COPYBUFSIZ, copystream);
 
            sigint_interrupt_enabled = false;
 
            if (buflen <= 0)
                break;
 
            if (PQputCopyData(conn, buf, buflen) <= 0)
            {
                OK = false;
                break;
            }
        }
    }
    else
    {
        bool        copydone = false;
        int         buflen;
        bool        at_line_begin = true;
 
        /*
         * In text mode, we have to read the input one line at a time, so that
         * we can stop reading at the EOF marker (\.).  We mustn't read beyond
         * the EOF marker, because if the data was inlined in a SQL script, we
         * would eat up the commands after the EOF marker.
         */
        buflen = 0;
        while (!copydone)
        {
            char       *fgresult;
 
            if (at_line_begin && showprompt)
            {
                const char *prompt = get_prompt(PROMPT_COPY, NULL);
 
                fputs(prompt, stdout);
                fflush(stdout);
            }
 
            /* enable longjmp while waiting for input */
            sigint_interrupt_enabled = true;
 
            fgresult = fgets(&buf[buflen], COPYBUFSIZ - buflen, copystream);
 
            sigint_interrupt_enabled = false;
 
            if (!fgresult)
                copydone = true;
            else
            {
                int         linelen;
 
                linelen = strlen(fgresult);
                buflen += linelen;
 
                /* current line is done? */
                if (buf[buflen - 1] == '\n')
                {
                    /* check for EOF marker, but not on a partial line */
                    if (at_line_begin)
                    {
                        /*
                         * This code erroneously assumes '\.' on a line alone
                         * inside a quoted CSV string terminates the \copy.
                         * https://www.postgresql.org/message-id/E1TdNVQ-0001ju-GO@wrigleys.postgresql.org
                         *
                         * https://www.postgresql.org/message-id/bfcd57e4-8f23-4c3e-a5db-2571d09208e2@beta.fastmail.com
                         */
                        if ((linelen == 3 && memcmp(fgresult, "\\.\n", 3) == 0) ||
                            (linelen == 4 && memcmp(fgresult, "\\.\r\n", 4) == 0))
                        {
                            copydone = true;
                        }
                    }
 
                    if (copystream == pset.cur_cmd_source)
                    {
                        pset.lineno++;
                        pset.stmt_lineno++;
                    }
                    at_line_begin = true;
                }
                else
                    at_line_begin = false;
            }
 
            /*
             * If the buffer is full, or we've reached the EOF, flush it.
             *
             * Make sure there's always space for four more bytes in the
             * buffer, plus a NUL terminator.  That way, an EOF marker is
             * never split across two fgets() calls, which simplifies the
             * logic.
             */
            if (buflen >= COPYBUFSIZ - 5 || (copydone && buflen > 0))
            {
                if (PQputCopyData(conn, buf, buflen) <= 0)
                {
                    OK = false;
                    break;
                }
 
                buflen = 0;
            }
        }
    }
 
    /* Check for read error */
    if (ferror(copystream))
        OK = false;
 
    /*
     * Terminate data transfer.  We can't send an error message if we're using
     * protocol version 2.  (libpq no longer supports protocol version 2, but
     * keep the version checks just in case you're using a pre-v14 libpq.so at
     * runtime)
     */
    if (PQputCopyEnd(conn,
                     (OK || PQprotocolVersion(conn) < 3) ? NULL :
                     _("aborted because of read failure")) <= 0)
        OK = false;
 
copyin_cleanup:
 
    /*
     * Clear the EOF flag on the stream, in case copying ended due to an EOF
     * signal.  This allows an interactive TTY session to perform another COPY
     * FROM STDIN later.  (In non-STDIN cases, we're about to close the file
     * anyway, so it doesn't matter.)  Although we don't ever test the flag
     * with feof(), some fread() implementations won't read more data if it's
     * set.  This also clears the error flag, but we already checked that.
     */
    clearerr(copystream);
 
    /*
     * Check command status and return to normal libpq state.
     *
     * We do not want to return with the status still PGRES_COPY_IN: our
     * caller would be unable to distinguish that situation from reaching the
     * next COPY in a command string that happened to contain two consecutive
     * COPY FROM STDIN commands.  We keep trying PQputCopyEnd() in the hope
     * it'll work eventually.  (What's actually likely to happen is that in
     * attempting to flush the data, libpq will eventually realize that the
     * connection is lost.  But that's fine; it will get us out of COPY_IN
     * state, which is what we need.)
     */
    while (*res = PQgetResult(conn), PQresultStatus(*res) == PGRES_COPY_IN)
    {
        OK = false;
        PQclear(*res);
        /* We can't send an error message if we're using protocol version 2 */
        PQputCopyEnd(conn,
                     (PQprotocolVersion(conn) < 3) ? NULL :
                     _("trying to exit copy mode"));
    }
    if (PQresultStatus(*res) != PGRES_COMMAND_OK)
    {
        pg_log_info("%s", PQerrorMessage(conn));
        OK = false;
    }
 
    return OK;
}

References _, buf, conn, COPYBUFSIZ, _psqlSettings::cur_cmd_source, fflush(), get_prompt(), _psqlSettings::lineno, pg_log_info, PGRES_COMMAND_OK, PGRES_COPY_IN, PQclear(), PQerrorMessage(), PQgetResult(), PQprotocolVersion(), PQputCopyData(), PQputCopyEnd(), PQresultStatus(), PROMPT_COPY, pset, _psqlSettings::quiet, res, sigint_interrupt_enabled, sigint_interrupt_jmp, generate_unaccent_rules::stdout, and _psqlSettings::stmt_lineno.

Referenced by HandleCopyResult().

handleCopyOut()

bool handleCopyOut	(	PGconn *	conn,
		FILE *	copystream,
		PGresult **	res
	)

Definition at line 434 of file copy.c.

{
    bool        OK = true;
    char       *buf;
    int         ret;
 
    for (;;)
    {
        ret = PQgetCopyData(conn, &buf, 0);
 
        if (ret < 0)
            break;              /* done or server/connection error */
 
        if (buf)
        {
            if (OK && copystream && fwrite(buf, 1, ret, copystream) != ret)
            {
                pg_log_error("could not write COPY data: %m");
                /* complain only once, keep reading data from server */
                OK = false;
            }
            PQfreemem(buf);
        }
    }
 
    if (OK && copystream && fflush(copystream))
    {
        pg_log_error("could not write COPY data: %m");
        OK = false;
    }
 
    if (ret == -2)
    {
        pg_log_error("COPY data transfer failed: %s", PQerrorMessage(conn));
        OK = false;
    }
 
    /*
     * Check command status and return to normal libpq state.
     *
     * If for some reason libpq is still reporting PGRES_COPY_OUT state, we
     * would like to forcibly exit that state, since our caller would be
     * unable to distinguish that situation from reaching the next COPY in a
     * command string that happened to contain two consecutive COPY TO STDOUT
     * commands.  However, libpq provides no API for doing that, and in
     * principle it's a libpq bug anyway if PQgetCopyData() returns -1 or -2
     * but hasn't exited COPY_OUT state internally.  So we ignore the
     * possibility here.
     */
    *res = PQgetResult(conn);
    if (PQresultStatus(*res) != PGRES_COMMAND_OK)
    {
        pg_log_info("%s", PQerrorMessage(conn));
        OK = false;
    }
 
    return OK;
}

References buf, conn, fflush(), pg_log_error, pg_log_info, PGRES_COMMAND_OK, PQerrorMessage(), PQfreemem(), PQgetCopyData(), PQgetResult(), PQresultStatus(), and res.

Referenced by HandleCopyResult().