Add files to do read I/O on the cluster directory:

	pg_stat_file()
	pg_read_file()
	pg_ls_dir()
	pg_reload_conf()
	pg_rotate_logfile()

Dave Page
Andreas Pflug

1 files changed, 258 insertions, 0 deletions

diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
new file mode 100644
index 00000000000..cd34b54da50
--- /dev/null
+++ b/src/backend/utils/adt/genfile.c
@@ -0,0 +1,258 @@
+/*-------------------------------------------------------------------------
+ *
+ * genfile.c
+ *
+ *
+ * Copyright (c) 2004, PostgreSQL Global Development Group
+ * 
+ * Author: Andreas Pflug <pgadmin@pse-consulting.de>
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/genfile.c,v 1.1 2005/08/12 03:24:08 momjian Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <dirent.h>
+
+#include "utils/builtins.h"
+#include "miscadmin.h"
+#include "storage/fd.h"
+#include "catalog/pg_type.h"
+#include "funcapi.h"
+
+extern  char *Log_directory;
+
+typedef struct 
+{
+	char	*location;
+	DIR		*dirdesc;
+} directory_fctx;
+
+/*
+ * Return an absolute path. Argument may be absolute or 
+ * relative to the DataDir.
+ */
+static char *check_and_make_absolute(text *arg)
+{
+	int datadir_len = strlen(DataDir);
+	int filename_len = VARSIZE(arg) - VARHDRSZ;
+	char *filename = palloc(filename_len + 1);
+	
+	memcpy(filename, VARDATA(arg), filename_len);
+	filename[filename_len] = '\0';
+
+	canonicalize_path(filename);
+	filename_len = strlen(filename);	/* recompute */
+
+	/*
+	 *	Prevent reference to the parent directory.
+	 *	"..a.." is a valid file name though.
+	 */
+	if (strcmp(filename, "..") == 0 ||							/* beginning */
+		strncmp(filename, "../", 3) == 0 ||						/* beginning */
+		strcmp(filename, "/..") == 0 ||							/* beginning */
+		strncmp(filename, "../", 3) == 0 ||						/* beginning */
+		strstr(filename, "/../") != NULL ||						/* middle */
+		strncmp(filename + filename_len - 3, "/..", 3) == 0)	/* end */
+			ereport(ERROR,
+				  (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				   (errmsg("Reference to a parent directory (\"..\") not allowed"))));
+
+	if (is_absolute_path(filename))
+	{
+		/* The log directory might be outside our datadir, but allow it */
+	    if (is_absolute_path(Log_directory) &&
+			strncmp(filename, Log_directory, strlen(Log_directory)) == 0 &&
+			(filename[strlen(Log_directory)] == '/' ||
+			 filename[strlen(Log_directory)] == '\0'))
+			return filename;
+
+	    ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 (errmsg("Absolute paths not allowed"))));
+		return NULL;
+	}
+	else
+	{
+	    char *absname = palloc(datadir_len + filename_len + 2);
+		sprintf(absname, "%s/%s", DataDir, filename);
+		pfree(filename);
+		return absname;
+	}
+}
+
+
+Datum pg_read_file(PG_FUNCTION_ARGS)
+{
+	int64		bytes_to_read = PG_GETARG_INT64(2);
+	int64		seek_offset = PG_GETARG_INT64(1);
+	char 		*buf = 0;
+	size_t		nbytes;
+	FILE		*file;
+	char		*filename;
+
+	if (!superuser())
+	    ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 (errmsg("must be superuser to read files"))));
+
+	filename = check_and_make_absolute(PG_GETARG_TEXT_P(0));
+
+	if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)
+	{
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not open file %s for reading: %m", filename)));
+		PG_RETURN_NULL();
+	}
+
+	if (fseeko(file, (off_t)seek_offset,
+		(seek_offset >= 0) ? SEEK_SET : SEEK_END) != 0)
+	{
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not seek in file %s: %m", filename)));
+		PG_RETURN_NULL();
+	}
+
+	if (bytes_to_read < 0)
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("length cannot be negative")));
+	}
+	
+	buf = palloc(bytes_to_read + VARHDRSZ);
+
+	nbytes = fread(VARDATA(buf), 1, bytes_to_read, file);
+
+	if (nbytes < 0)
+	{
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not read file %s: %m", filename)));
+		PG_RETURN_NULL();
+	}
+	VARATT_SIZEP(buf) = nbytes + VARHDRSZ;
+
+	pfree(filename);
+	FreeFile(file);
+	PG_RETURN_TEXT_P(buf);
+}
+
+
+Datum pg_stat_file(PG_FUNCTION_ARGS)
+{
+	AttInMetadata *attinmeta;
+	char		*filename = check_and_make_absolute(PG_GETARG_TEXT_P(0));
+	struct stat fst;
+	char		lenbuf[30], cbuf[30], abuf[30], mbuf[30], dirbuf[2];
+	char		*values[5] = {lenbuf, cbuf, abuf, mbuf, dirbuf};
+	pg_time_t	timestamp;
+	HeapTuple	tuple;
+	TupleDesc	tupdesc = CreateTemplateTupleDesc(5, false);
+
+	if (!superuser())
+	    ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 (errmsg("must be superuser to get file information"))));
+
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, "length", INT8OID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 2, "atime", TIMESTAMPOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 3, "mtime", TIMESTAMPOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 4, "ctime", TIMESTAMPOID, -1, 0);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 5, "isdir", BOOLOID, -1, 0);
+	attinmeta = TupleDescGetAttInMetadata(tupdesc);
+
+	if (stat(filename, &fst) < 0)
+	{
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not stat file %s: %m", filename)));
+		PG_RETURN_NULL();
+	}
+	else
+	{
+		snprintf(lenbuf, 30, INT64_FORMAT, (int64)fst.st_size);
+
+		timestamp = fst.st_atime;
+		pg_strftime(abuf, 30, "%F %T", pg_localtime(&timestamp, global_timezone));
+
+		timestamp = fst.st_mtime;
+		pg_strftime(mbuf, 30, "%F %T", pg_localtime(&timestamp, global_timezone));
+
+		timestamp = fst.st_ctime;
+		pg_strftime(cbuf, 30, "%F %T", pg_localtime(&timestamp, global_timezone));
+
+		if (fst.st_mode & S_IFDIR)
+			strcpy(dirbuf, "t");
+		else
+			strcpy(dirbuf, "f");
+
+		tuple = BuildTupleFromCStrings(attinmeta, values);
+		pfree(filename);
+		PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
+	}
+}
+
+
+Datum pg_ls_dir(PG_FUNCTION_ARGS)
+{
+	FuncCallContext	*funcctx;
+	struct dirent	*de;
+	directory_fctx	*fctx;
+
+	if (!superuser())
+	    ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 (errmsg("must be superuser to get directory listings"))));
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		MemoryContext oldcontext;
+
+		funcctx = SRF_FIRSTCALL_INIT();
+		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+
+		fctx = palloc(sizeof(directory_fctx));
+		fctx->location = check_and_make_absolute(PG_GETARG_TEXT_P(0));
+
+		fctx->dirdesc = AllocateDir(fctx->location);
+
+		if (!fctx->dirdesc)
+		    ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("%s is not browsable: %m", fctx->location)));
+
+		funcctx->user_fctx = fctx;
+		MemoryContextSwitchTo(oldcontext);
+	}
+
+	funcctx = SRF_PERCALL_SETUP();
+	fctx = (directory_fctx*) funcctx->user_fctx;
+
+	if (!fctx->dirdesc)  /* not a readable directory  */
+		SRF_RETURN_DONE(funcctx);
+
+	while ((de = ReadDir(fctx->dirdesc, fctx->location)) != NULL)
+	{
+		int			len = strlen(de->d_name);
+		text		*result = palloc(len + VARHDRSZ);
+
+		if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
+		    continue;
+
+		VARATT_SIZEP(result) = len + VARHDRSZ;
+		memcpy(VARDATA(result), de->d_name, len);
+
+		SRF_RETURN_NEXT(funcctx, PointerGetDatum(result));
+	}
+
+	FreeDir(fctx->dirdesc);
+	SRF_RETURN_DONE(funcctx);
+}