summaryrefslogtreecommitdiff
path: root/src/bin/pg_rewind/copy_fetch.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/bin/pg_rewind/copy_fetch.c')
-rw-r--r--src/bin/pg_rewind/copy_fetch.c261
1 files changed, 261 insertions, 0 deletions
diff --git a/src/bin/pg_rewind/copy_fetch.c b/src/bin/pg_rewind/copy_fetch.c
new file mode 100644
index 0000000000..887fec9c9d
--- /dev/null
+++ b/src/bin/pg_rewind/copy_fetch.c
@@ -0,0 +1,261 @@
+/*-------------------------------------------------------------------------
+ *
+ * copy_fetch.c
+ * Functions for using a data directory as the source.
+ *
+ * Portions Copyright (c) 2013-2015, PostgreSQL Global Development Group
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres_fe.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "datapagemap.h"
+#include "fetch.h"
+#include "file_ops.h"
+#include "filemap.h"
+#include "logging.h"
+#include "pg_rewind.h"
+
+#include "catalog/catalog.h"
+
+static void recurse_dir(const char *datadir, const char *path,
+ process_file_callback_t callback);
+
+static void execute_pagemap(datapagemap_t *pagemap, const char *path);
+
+/*
+ * Traverse through all files in a data directory, calling 'callback'
+ * for each file.
+ */
+void
+traverse_datadir(const char *datadir, process_file_callback_t callback)
+{
+ recurse_dir(datadir, NULL, callback);
+}
+
+/*
+ * recursive part of traverse_datadir
+ */
+static void
+recurse_dir(const char *datadir, const char *parentpath,
+ process_file_callback_t callback)
+{
+ DIR *xldir;
+ struct dirent *xlde;
+ char fullparentpath[MAXPGPATH];
+
+ if (parentpath)
+ snprintf(fullparentpath, MAXPGPATH, "%s/%s", datadir, parentpath);
+ else
+ snprintf(fullparentpath, MAXPGPATH, "%s", datadir);
+
+ xldir = opendir(fullparentpath);
+ if (xldir == NULL)
+ pg_fatal("could not open directory \"%s\": %s\n",
+ fullparentpath, strerror(errno));
+
+ while (errno = 0, (xlde = readdir(xldir)) != NULL)
+ {
+ struct stat fst;
+ char fullpath[MAXPGPATH];
+ char path[MAXPGPATH];
+
+ if (strcmp(xlde->d_name, ".") == 0 ||
+ strcmp(xlde->d_name, "..") == 0)
+ continue;
+
+ snprintf(fullpath, MAXPGPATH, "%s/%s", fullparentpath, xlde->d_name);
+
+ if (lstat(fullpath, &fst) < 0)
+ {
+ pg_log(PG_WARNING, "could not stat file \"%s\": %s",
+ fullpath, strerror(errno));
+
+ /*
+ * This is ok, if the new master is running and the file was just
+ * removed. If it was a data file, there should be a WAL record of
+ * the removal. If it was something else, it couldn't have been
+ * critical anyway.
+ *
+ * TODO: But complain if we're processing the target dir!
+ */
+ }
+
+ if (parentpath)
+ snprintf(path, MAXPGPATH, "%s/%s", parentpath, xlde->d_name);
+ else
+ snprintf(path, MAXPGPATH, "%s", xlde->d_name);
+
+ if (S_ISREG(fst.st_mode))
+ callback(path, FILE_TYPE_REGULAR, fst.st_size, NULL);
+ else if (S_ISDIR(fst.st_mode))
+ {
+ callback(path, FILE_TYPE_DIRECTORY, 0, NULL);
+ /* recurse to handle subdirectories */
+ recurse_dir(datadir, path, callback);
+ }
+#ifndef WIN32
+ else if (S_ISLNK(fst.st_mode))
+#else
+ else if (pgwin32_is_junction(fullpath))
+#endif
+ {
+#if defined(HAVE_READLINK) || defined(WIN32)
+ char link_target[MAXPGPATH];
+ ssize_t len;
+
+ len = readlink(fullpath, link_target, sizeof(link_target) - 1);
+ if (len == -1)
+ pg_fatal("readlink() failed on \"%s\": %s\n",
+ fullpath, strerror(errno));
+
+ if (len == sizeof(link_target) - 1)
+ {
+ /* path was truncated */
+ pg_fatal("symbolic link \"%s\" target path too long\n",
+ fullpath);
+ }
+
+ callback(path, FILE_TYPE_SYMLINK, 0, link_target);
+
+ /*
+ * If it's a symlink within pg_tblspc, we need to recurse into it,
+ * to process all the tablespaces.
+ */
+ if (strcmp(parentpath, "pg_tblspc") == 0)
+ recurse_dir(datadir, path, callback);
+#else
+ pg_fatal("\"%s\" is a symbolic link, but symbolic links are not supported on this platform\n",
+ fullpath);
+#endif /* HAVE_READLINK */
+ }
+ }
+
+ if (errno)
+ pg_fatal("could not read directory \"%s\": %s\n",
+ fullparentpath, strerror(errno));
+
+ if (closedir(xldir))
+ pg_fatal("could not close archive location \"%s\": %s\n",
+ fullparentpath, strerror(errno));
+}
+
+/*
+ * Copy a file from source to target, between 'begin' and 'end' offsets.
+ *
+ * If 'trunc' is true, any existing file with the same name is truncated.
+ */
+static void
+copy_file_range(const char *path, off_t begin, off_t end, bool trunc)
+{
+ char buf[BLCKSZ];
+ char srcpath[MAXPGPATH];
+ int srcfd;
+
+ snprintf(srcpath, sizeof(srcpath), "%s/%s", datadir_source, path);
+
+ srcfd = open(srcpath, O_RDONLY | PG_BINARY, 0);
+ if (srcfd < 0)
+ pg_fatal("could not open source file \"%s\": %s\n",
+ srcpath, strerror(errno));
+
+ if (lseek(srcfd, begin, SEEK_SET) == -1)
+ pg_fatal("could not seek in source file: %s\n", strerror(errno));
+
+ open_target_file(path, trunc);
+
+ while (end - begin > 0)
+ {
+ int readlen;
+ int len;
+
+ if (end - begin > sizeof(buf))
+ len = sizeof(buf);
+ else
+ len = end - begin;
+
+ readlen = read(srcfd, buf, len);
+
+ if (readlen < 0)
+ pg_fatal("could not read file \"%s\": %s\n",
+ srcpath, strerror(errno));
+ else if (readlen == 0)
+ pg_fatal("unexpected EOF while reading file \"%s\"\n", srcpath);
+
+ write_target_range(buf, begin, readlen);
+ begin += readlen;
+ }
+
+ if (close(srcfd) != 0)
+ pg_fatal("error closing file \"%s\": %s\n", srcpath, strerror(errno));
+}
+
+/*
+ * Copy all relation data files from datadir_source to datadir_target, which
+ * are marked in the given data page map.
+ */
+void
+copy_executeFileMap(filemap_t *map)
+{
+ file_entry_t *entry;
+ int i;
+
+ for (i = 0; i < map->narray; i++)
+ {
+ entry = map->array[i];
+ execute_pagemap(&entry->pagemap, entry->path);
+
+ switch (entry->action)
+ {
+ case FILE_ACTION_NONE:
+ /* ok, do nothing.. */
+ break;
+
+ case FILE_ACTION_COPY:
+ copy_file_range(entry->path, 0, entry->newsize, true);
+ break;
+
+ case FILE_ACTION_TRUNCATE:
+ truncate_target_file(entry->path, entry->newsize);
+ break;
+
+ case FILE_ACTION_COPY_TAIL:
+ copy_file_range(entry->path, entry->oldsize, entry->newsize, false);
+ break;
+
+ case FILE_ACTION_CREATE:
+ create_target(entry);
+ break;
+
+ case FILE_ACTION_REMOVE:
+ remove_target(entry);
+ break;
+ }
+ }
+
+ close_target_file();
+}
+
+static void
+execute_pagemap(datapagemap_t *pagemap, const char *path)
+{
+ datapagemap_iterator_t *iter;
+ BlockNumber blkno;
+ off_t offset;
+
+ iter = datapagemap_iterate(pagemap);
+ while (datapagemap_next(iter, &blkno))
+ {
+ offset = blkno * BLCKSZ;
+ copy_file_range(path, offset, offset + BLCKSZ, false);
+ /* Ok, this block has now been copied from new data dir to old */
+ }
+ free(iter);
+}
View Lorry Controller Status