pg_waldump: Remove file-level global WalSegSz.

It's better style to pass the value around to just the places that
need it. This makes it easier to determine whether the value is
always properly initialized before use.

Reviewed-by: Amul Sul <sulamul@gmail.com>
Discussion: http://postgr.es/m/CAAJ_b94+wObPn-z1VECipnSFhjMJ+R2cpTmKVYLjyQuVn+B5QA@mail.gmail.com

diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c
index aae655966ef2d458aa6fba8e392b79276b1832c9..f3446385d6aab7408fa00f7a412c1a78d27a77fb 100644 (file)
--- a/src/bin/pg_waldump/pg_waldump.c
+++ b/src/bin/pg_waldump/pg_waldump.c
@@ -39,7 +39,6 @@
 
 static const char *progname;
 
-static int     WalSegSz;
 static volatile sig_atomic_t time_to_stop = false;
 
 static const RelFileLocator emptyRelFileLocator = {0, 0, 0};
@@ -203,11 +202,11 @@ open_file_in_directory(const char *directory, const char *fname)
 /*
  * Try to find fname in the given directory. Returns true if it is found,
  * false otherwise. If fname is NULL, search the complete directory for any
- * file with a valid WAL file name. If file is successfully opened, set the
- * wal segment size.
+ * file with a valid WAL file name. If file is successfully opened, set
+ * *WaSegSz to the WAL segment size.
  */
 static bool
-search_directory(const char *directory, const char *fname)
+search_directory(const char *directory, const char *fname, int *WalSegSz)
 {
        int                     fd = -1;
        DIR                *xldir;
@@ -249,17 +248,17 @@ search_directory(const char *directory, const char *fname)
                {
                        XLogLongPageHeader longhdr = (XLogLongPageHeader) buf.data;
 
-                       WalSegSz = longhdr->xlp_seg_size;
-
-                       if (!IsValidWalSegSize(WalSegSz))
+                       if (!IsValidWalSegSize(longhdr->xlp_seg_size))
                        {
                                pg_log_error(ngettext("invalid WAL segment size in WAL file \"%s\" (%d byte)",
                                                                          "invalid WAL segment size in WAL file \"%s\" (%d bytes)",
-                                                                         WalSegSz),
-                                                        fname, WalSegSz);
+                                                                         longhdr->xlp_seg_size),
+                                                        fname, longhdr->xlp_seg_size);
                                pg_log_error_detail("The WAL segment size must be a power of two between 1 MB and 1 GB.");
                                exit(1);
                        }
+
+                       *WalSegSz = longhdr->xlp_seg_size;
                }
                else if (r < 0)
                        pg_fatal("could not read file \"%s\": %m",
@@ -286,21 +285,22 @@ search_directory(const char *directory, const char *fname)
  *      XLOGDIR /
  *      $PGDATA / XLOGDIR /
  *
- * The valid target directory is returned.
+ * The valid target directory is returned, and *WalSegSz is set to the
+ * size of the WAL segment found in that directory.
  */
 static char *
-identify_target_directory(char *directory, char *fname)
+identify_target_directory(char *directory, char *fname, int *WalSegSz)
 {
        char            fpath[MAXPGPATH];
 
        if (directory != NULL)
        {
-               if (search_directory(directory, fname))
+               if (search_directory(directory, fname, WalSegSz))
                        return pg_strdup(directory);
 
                /* directory / XLOGDIR */
                snprintf(fpath, MAXPGPATH, "%s/%s", directory, XLOGDIR);
-               if (search_directory(fpath, fname))
+               if (search_directory(fpath, fname, WalSegSz))
                        return pg_strdup(fpath);
        }
        else
@@ -308,10 +308,10 @@ identify_target_directory(char *directory, char *fname)
                const char *datadir;
 
                /* current directory */
-               if (search_directory(".", fname))
+               if (search_directory(".", fname, WalSegSz))
                        return pg_strdup(".");
                /* XLOGDIR */
-               if (search_directory(XLOGDIR, fname))
+               if (search_directory(XLOGDIR, fname, WalSegSz))
                        return pg_strdup(XLOGDIR);
 
                datadir = getenv("PGDATA");
@@ -319,7 +319,7 @@ identify_target_directory(char *directory, char *fname)
                if (datadir != NULL)
                {
                        snprintf(fpath, MAXPGPATH, "%s/%s", datadir, XLOGDIR);
-                       if (search_directory(fpath, fname))
+                       if (search_directory(fpath, fname, WalSegSz))
                                return pg_strdup(fpath);
                }
        }
@@ -801,6 +801,7 @@ main(int argc, char **argv)
        XLogRecPtr      first_record;
        char       *waldir = NULL;
        char       *errormsg;
+       int                     WalSegSz;
 
        static struct option long_options[] = {
                {"bkp-details", no_argument, NULL, 'b'},
@@ -1127,7 +1128,7 @@ main(int argc, char **argv)
                                pg_fatal("could not open directory \"%s\": %m", waldir);
                }
 
-               waldir = identify_target_directory(waldir, fname);
+               waldir = identify_target_directory(waldir, fname, &WalSegSz);
                fd = open_file_in_directory(waldir, fname);
                if (fd < 0)
                        pg_fatal("could not open file \"%s\"", fname);
@@ -1189,7 +1190,7 @@ main(int argc, char **argv)
                }
        }
        else
-               waldir = identify_target_directory(waldir, NULL);
+               waldir = identify_target_directory(waldir, NULL, &WalSegSz);
 
        /* we don't know what to print */
        if (!XLogRecPtrIsValid(private.startptr))