PostgreSQL的 initdb 源代码分析之十

继续分析，

如下这段，因为条件不成立，被跳过：

    /* Create transaction log symlink, if required */
    if (strcmp(xlog_dir, "") != 0)
    {

        fprintf(stderr,"In main function -----------------190
");

        char       *linkloc;

        /* clean up xlog directory name, check it's absolute */
        canonicalize_path(xlog_dir);
        if (!is_absolute_path(xlog_dir))
        {
            fprintf(stderr, _("%s: transaction log directory location must be an absolute path
"), progname);
            exit_nicely();
        }

        /* check if the specified xlog directory exists/is empty */
        switch (pg_check_dir(xlog_dir))
        {
            case 0:
                /* xlog directory not there, must create it */
                printf(_("creating directory %s ... "),
                       xlog_dir);
                fflush(stdout);

                if (pg_mkdir_p(xlog_dir, S_IRWXU) != 0)
                {
                    fprintf(stderr, _("%s: could not create directory "%s": %s
"),
                            progname, xlog_dir, strerror(errno));
                    exit_nicely();
                }
                else
                    check_ok();

                made_new_xlogdir = true;
                break;

            case 1:
                /* Present but empty, fix permissions and use it */
                printf(_("fixing permissions on existing directory %s ... "),
                       xlog_dir);
                fflush(stdout);

                if (chmod(xlog_dir, S_IRWXU) != 0)
                {
                    fprintf(stderr, _("%s: could not change permissions of directory "%s": %s
"),
                            progname, xlog_dir, strerror(errno));
                    exit_nicely();
                }
                else
                    check_ok();

                found_existing_xlogdir = true;
                break;

            case 2:
                /* Present and not empty */
                fprintf(stderr,
                        _("%s: directory "%s" exists but is not empty
"),
                        progname, xlog_dir);
                fprintf(stderr,
                 _("If you want to store the transaction log there, either
"
                   "remove or empty the directory "%s".
"),
                        xlog_dir);
                exit_nicely();

            default:
                /* Trouble accessing directory */
                fprintf(stderr, _("%s: could not access directory "%s": %s
"),
                        progname, xlog_dir, strerror(errno));
                exit_nicely();
        }

        /* form name of the place where the symlink must go */
        linkloc = (char *) pg_malloc(strlen(pg_data) + 8 + 1);
        sprintf(linkloc, "%s/pg_xlog", pg_data);

#ifdef HAVE_SYMLINK
        if (symlink(xlog_dir, linkloc) != 0)
        {
            fprintf(stderr, _("%s: could not create symbolic link "%s": %s
"),
                    progname, linkloc, strerror(errno));
            exit_nicely();
        }
#else
        fprintf(stderr, _("%s: symlinks are not supported on this platform"));
        exit_nicely();
#endif
    }

接下来：

开始创建各个子目录

    /* Create required subdirectories */
    printf(_("creating subdirectories ... "));
    fflush(stdout);

    for (i = 0; i < (sizeof(subdirs) / sizeof(char *)); i++)
    {
        if (!mkdatadir(subdirs[i]))
            exit_nicely();
    }

加入调试代码后，可以看到，上述建立的各子目录分别是：

subdirs[0] is: global

subdirs[1] is: pg_xlog

subdirs[2] is: pg_xlog/archive_status

subdirs[3] is: pg_clog

subdirs[4] is: pg_notify

subdirs[5] is: pg_serial

subdirs[6] is: pg_subtrans

subdirs[7] is: pg_twophase

subdirs[8] is: pg_multixact/members

subdirs[9] is: pg_multixact/offsets

subdirs[10] is: base

subdirs[11] is: base/1

subdirs[12] is: pg_tblspc

subdirs[13] is: pg_stat_tmp

想起来了，前面有过定义的：

    static const char *subdirs[] = {
        "global",
        "pg_xlog",
        "pg_xlog/archive_status",
        "pg_clog",
        "pg_notify",
        "pg_serial",
        "pg_subtrans",
        "pg_twophase",
        "pg_multixact/members",
        "pg_multixact/offsets",
        "base",
        "base/1",
        "pg_tblspc",
        "pg_stat_tmp"
    };

而接下来，就是：

    check_ok();

这个check_ok ，其注释就说得很清楚：

/*
 * call exit_nicely() if we got a signal, or else output "ok".
 */
static void
check_ok(void)
{
    if (caught_signal)
    {
        printf(_("caught signal
"));
        fflush(stdout);
        exit_nicely();
    }
    else if (output_failed)
    {
        printf(_("could not write to child process: %s
"),
               strerror(output_errno));
        fflush(stdout);
        exit_nicely();
    }
    else
    {
        /* all seems well */
        printf(_("ok
"));
        fflush(stdout);
    }
}