rmtree.c

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/*-------------------------------------------------------------------------
 *
 * rmtree.c
 *
 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/common/rmtree.c
 *
 *-------------------------------------------------------------------------
 */

#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif

#include <unistd.h>
#include <sys/stat.h>

#ifndef FRONTEND
#define pg_log_warning(...) elog(WARNING, __VA_ARGS__)
#else
#include "common/logging.h"
#endif


/*
 *  rmtree
 *
 *  Delete a directory tree recursively.
 *  Assumes path points to a valid directory.
 *  Deletes everything under path.
 *  If rmtopdir is true deletes the directory too.
 *  Returns true if successful, false if there was any problem.
 *  (The details of the problem are reported already, so caller
 *  doesn't really have to say anything more, but most do.)
 */
bool
rmtree(const char *path, bool rmtopdir)
{
    bool        result = true;
    char        pathbuf[MAXPGPATH];
    char      **filenames;
    char      **filename;
    struct stat statbuf;

    /*
     * we copy all the names out of the directory before we start modifying
     * it.
     */
    filenames = pgfnames(path);

    if (filenames == NULL)
        return false;

    /* now we have the names we can start removing things */
    for (filename = filenames; *filename; filename++)
    {
        snprintf(pathbuf, MAXPGPATH, "%s/%s", path, *filename);

        /*
         * It's ok if the file is not there anymore; we were just about to
         * delete it anyway.
         *
         * This is not an academic possibility. One scenario where this
         * happens is when bgwriter has a pending unlink request for a file in
         * a database that's being dropped. In dropdb(), we call
         * ForgetDatabaseSyncRequests() to flush out any such pending unlink
         * requests, but because that's asynchronous, it's not guaranteed that
         * the bgwriter receives the message in time.
         */
        if (lstat(pathbuf, &statbuf) != 0)
        {
            if (errno != ENOENT)
            {
                pg_log_warning("could not stat file or directory \"%s\": %m",
                               pathbuf);
                result = false;
            }
            continue;
        }

        if (S_ISDIR(statbuf.st_mode))
        {
            /* call ourselves recursively for a directory */
            if (!rmtree(pathbuf, true))
            {
                /* we already reported the error */
                result = false;
            }
        }
        else
        {
            if (unlink(pathbuf) != 0)
            {
                if (errno != ENOENT)
                {
                    pg_log_warning("could not remove file or directory \"%s\": %m",
                                   pathbuf);
                    result = false;
                }
            }
        }
    }

    if (rmtopdir)
    {
        if (rmdir(path) != 0)
        {
            pg_log_warning("could not remove file or directory \"%s\": %m",
                           path);
            result = false;
        }
    }

    pgfnames_cleanup(filenames);

    return result;
}