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Additional "standby clone" code
We'll break up the unwieldy "do_standby_clone()" function into discrete unit for easier maintenance.
This commit is contained in:
Ian Barwick
341
dirutil.c
Normal file
341
dirutil.c
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@@ -0,0 +1,341 @@
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/*
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*
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* dirmod.c
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* directory handling functions
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*
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* Copyright (c) 2ndQuadrant, 2010-2017
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*/
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#include <unistd.h>
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#include <dirent.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <stdio.h>
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#include <string.h>
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#include <ftw.h>
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/* NB: postgres_fe must be included BEFORE check_dir */
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#include <libpq-fe.h>
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#include <postgres_fe.h>
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#include "dirutil.h"
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#include "strutil.h"
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#include "log.h"
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static bool _create_pg_dir(char *dir, bool force, bool for_witness);
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static int unlink_dir_callback(const char *fpath, const struct stat *sb, int typeflag, struct FTW *ftwbuf);
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/*
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* make sure the directory either doesn't exist or is empty
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* we use this function to check the new data directory and
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* the directories for tablespaces
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*
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* This is the same check initdb does on the new PGDATA dir
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*
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* Returns 0 if nonexistent, 1 if exists and empty, 2 if not empty,
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* or -1 if trouble accessing directory
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*/
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int
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check_dir(char *path)
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{
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DIR *chkdir;
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struct dirent *file;
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int result = 1;
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errno = 0;
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chkdir = opendir(path);
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if (!chkdir)
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return (errno == ENOENT) ? 0 : -1;
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while ((file = readdir(chkdir)) != NULL)
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{
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if (strcmp(".", file->d_name) == 0 ||
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strcmp("..", file->d_name) == 0)
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{
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/* skip this and parent directory */
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continue;
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}
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else
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{
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result = 2; /* not empty */
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break;
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}
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}
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#ifdef WIN32
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/*
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* This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but not in
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* released version
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*/
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if (GetLastError() == ERROR_NO_MORE_FILES)
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errno = 0;
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#endif
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closedir(chkdir);
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if (errno != 0)
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return -1; /* some kind of I/O error? */
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return result;
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}
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/*
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* Create directory with error log message when failing
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*/
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bool
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create_dir(char *path)
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{
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if (mkdir_p(path, 0700) == 0)
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return true;
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log_error(_("unable to create directory \"%s\": %s"),
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path, strerror(errno));
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return false;
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}
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bool
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set_dir_permissions(char *path)
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{
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return (chmod(path, 0700) != 0) ? false : true;
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}
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/* function from initdb.c */
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/* source adapted from FreeBSD /src/bin/mkdir/mkdir.c */
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/*
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* this tries to build all the elements of a path to a directory a la mkdir -p
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* we assume the path is in canonical form, i.e. uses / as the separator
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* we also assume it isn't null.
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*
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* note that on failure, the path arg has been modified to show the particular
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* directory level we had problems with.
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*/
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int
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mkdir_p(char *path, mode_t omode)
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{
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struct stat sb;
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mode_t numask,
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oumask;
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int first,
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last,
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retval;
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char *p;
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p = path;
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oumask = 0;
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retval = 0;
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#ifdef WIN32
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/* skip network and drive specifiers for win32 */
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if (strlen(p) >= 2)
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{
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if (p[0] == '/' && p[1] == '/')
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{
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/* network drive */
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p = strstr(p + 2, "/");
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if (p == NULL)
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return 1;
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}
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else if (p[1] == ':' &&
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((p[0] >= 'a' && p[0] <= 'z') ||
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(p[0] >= 'A' && p[0] <= 'Z')))
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{
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/* local drive */
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p += 2;
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}
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}
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#endif
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if (p[0] == '/') /* Skip leading '/'. */
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++p;
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for (first = 1, last = 0; !last; ++p)
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{
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if (p[0] == '\0')
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last = 1;
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else if (p[0] != '/')
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continue;
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*p = '\0';
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if (!last && p[1] == '\0')
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last = 1;
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if (first)
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{
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/*
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* POSIX 1003.2: For each dir operand that does not name an
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* existing directory, effects equivalent to those caused by the
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* following command shall occcur:
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*
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* mkdir -p -m $(umask -S),u+wx $(dirname dir) && mkdir [-m mode]
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* dir
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*
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* We change the user's umask and then restore it, instead of
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* doing chmod's.
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*/
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oumask = umask(0);
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numask = oumask & ~(S_IWUSR | S_IXUSR);
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(void) umask(numask);
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first = 0;
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}
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if (last)
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(void) umask(oumask);
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/* check for pre-existing directory; ok if it's a parent */
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if (stat(path, &sb) == 0)
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{
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if (!S_ISDIR(sb.st_mode))
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{
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if (last)
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errno = EEXIST;
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else
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errno = ENOTDIR;
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retval = 1;
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break;
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}
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}
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else if (mkdir(path, last ? omode : S_IRWXU | S_IRWXG | S_IRWXO) < 0)
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{
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retval = 1;
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break;
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}
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if (!last)
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*p = '/';
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}
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if (!first && !last)
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(void) umask(oumask);
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return retval;
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}
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bool
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is_pg_dir(char *path)
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{
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const size_t buf_sz = 8192;
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char dirpath[buf_sz];
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struct stat sb;
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int r;
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/* test pgdata */
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snprintf(dirpath, buf_sz, "%s/PG_VERSION", path);
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if (stat(dirpath, &sb) == 0)
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return true;
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/* test tablespace dir */
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sprintf(dirpath, "ls %s/PG_*/ -I*", path);
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r = system(dirpath);
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if (r == 0)
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return true;
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return false;
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}
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bool
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create_pg_dir(char *path, bool force)
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{
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return _create_pg_dir(path, force, false);
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}
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bool
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create_witness_pg_dir(char *path, bool force)
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{
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return _create_pg_dir(path, force, true);
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}
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static bool
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_create_pg_dir(char *path, bool force, bool for_witness)
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{
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bool pg_dir = false;
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/* Check this directory could be used as a PGDATA dir */
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switch (check_dir(path))
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{
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case 0:
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/* dir not there, must create it */
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log_info(_("creating directory \"%s\"...\n"), path);
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if (!create_dir(path))
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{
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log_error(_("unable to create directory \"%s\"..."),
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path);
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return false;
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}
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break;
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case 1:
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/* Present but empty, fix permissions and use it */
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log_info(_("checking and correcting permissions on existing directory %s ...\n"),
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path);
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if (!set_dir_permissions(path))
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{
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log_error(_("unable to change permissions of directory \"%s\": %s"),
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path, strerror(errno));
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return false;
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}
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break;
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case 2:
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/* Present and not empty */
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log_warning(_("directory \"%s\" exists but is not empty\n"),
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path);
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pg_dir = is_pg_dir(path);
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if (pg_dir && force)
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{
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/*
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* The witness server does not store any data other than a copy of the
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* repmgr metadata, so in --force mode we can simply overwrite the
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* directory.
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*
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* For non-witness servers, we'll leave the data in place, both to reduce
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* the risk of unintentional data loss and to make it possible for the
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* data directory to be brought up-to-date with rsync.
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*/
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if (for_witness)
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{
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log_notice(_("deleting existing data directory \"%s\""), path);
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nftw(path, unlink_dir_callback, 64, FTW_DEPTH | FTW_PHYS);
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}
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/* Let it continue */
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break;
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}
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else if (pg_dir && !force)
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{
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log_hint(_("This looks like a PostgreSQL directory.\n"
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"If you are sure you want to clone here, "
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"please check there is no PostgreSQL server "
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"running and use the -F/--force option\n"));
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return false;
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}
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return false;
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default:
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log_error(_("could not access directory \"%s\": %s"),
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path, strerror(errno));
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return false;
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}
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return true;
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}
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static int
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unlink_dir_callback(const char *fpath, const struct stat *sb, int typeflag, struct FTW *ftwbuf)
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{
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int rv = remove(fpath);
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if (rv)
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perror(fpath);
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return rv;
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}
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