postgresql/contrib/adminpack/adminpack.c
Tom Lane 3a2d636598 Fix potentially-unportable code in contrib/adminpack.
Spelling access(2)'s second argument as "2" is just horrid.
POSIX makes no promises as to the numeric values of W_OK and related
macros.  Even if it accidentally works as intended on every supported
platform, it's still unreadable and inconsistent with adjacent code.

In passing, don't spell "NULL" as "0" either.  Yes, that's legal C;
no, it's not project style.

Back-patch, just in case the unportability is real and not theoretical.
(Most likely, even if a platform had different bit assignments for
access()'s modes, there'd not be an observable behavior difference
here; but I'm being paranoid today.)
2018-04-15 13:02:11 -04:00

576 lines
14 KiB
C

/*-------------------------------------------------------------------------
*
* adminpack.c
*
*
* Copyright (c) 2002-2018, PostgreSQL Global Development Group
*
* Author: Andreas Pflug <pgadmin@pse-consulting.de>
*
* IDENTIFICATION
* contrib/adminpack/adminpack.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <sys/file.h>
#include <sys/stat.h>
#include <unistd.h>
#include "catalog/pg_authid.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "postmaster/syslogger.h"
#include "storage/fd.h"
#include "utils/builtins.h"
#include "utils/datetime.h"
#ifdef WIN32
#ifdef rename
#undef rename
#endif
#ifdef unlink
#undef unlink
#endif
#endif
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(pg_file_write);
PG_FUNCTION_INFO_V1(pg_file_write_v1_1);
PG_FUNCTION_INFO_V1(pg_file_rename);
PG_FUNCTION_INFO_V1(pg_file_rename_v1_1);
PG_FUNCTION_INFO_V1(pg_file_unlink);
PG_FUNCTION_INFO_V1(pg_file_unlink_v1_1);
PG_FUNCTION_INFO_V1(pg_logdir_ls);
PG_FUNCTION_INFO_V1(pg_logdir_ls_v1_1);
static int64 pg_file_write_internal(text *file, text *data, bool replace);
static bool pg_file_rename_internal(text *file1, text *file2, text *file3);
static Datum pg_logdir_ls_internal(FunctionCallInfo fcinfo);
typedef struct
{
char *location;
DIR *dirdesc;
} directory_fctx;
/*-----------------------
* some helper functions
*/
/*
* Convert a "text" filename argument to C string, and check it's allowable.
*
* Filename may be absolute or relative to the DataDir, but we only allow
* absolute paths that match DataDir or Log_directory.
*/
static char *
convert_and_check_filename(text *arg, bool logAllowed)
{
char *filename = text_to_cstring(arg);
canonicalize_path(filename); /* filename can change length here */
/*
* Members of the 'pg_write_server_files' role are allowed to access any
* files on the server as the PG user, so no need to do any further checks
* here.
*/
if (is_member_of_role(GetUserId(), DEFAULT_ROLE_WRITE_SERVER_FILES))
return filename;
/* User isn't a member of the default role, so check if it's allowable */
if (is_absolute_path(filename))
{
/* Disallow '/a/b/data/..' */
if (path_contains_parent_reference(filename))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("reference to parent directory (\"..\") not allowed"))));
/*
* Allow absolute paths if within DataDir or Log_directory, even
* though Log_directory might be outside DataDir.
*/
if (!path_is_prefix_of_path(DataDir, filename) &&
(!logAllowed || !is_absolute_path(Log_directory) ||
!path_is_prefix_of_path(Log_directory, filename)))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("absolute path not allowed"))));
}
else if (!path_is_relative_and_below_cwd(filename))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("path must be in or below the current directory"))));
return filename;
}
/*
* check for superuser, bark if not.
*/
static void
requireSuperuser(void)
{
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("only superuser may access generic file functions"))));
}
/* ------------------------------------
* pg_file_write - old version
*
* The superuser() check here must be kept as the library might be upgraded
* without the extension being upgraded, meaning that in pre-1.1 installations
* these functions could be called by any user.
*/
Datum
pg_file_write(PG_FUNCTION_ARGS)
{
text *file = PG_GETARG_TEXT_PP(0);
text *data = PG_GETARG_TEXT_PP(1);
bool replace = PG_GETARG_BOOL(2);
int64 count = 0;
requireSuperuser();
count = pg_file_write_internal(file, data, replace);
PG_RETURN_INT64(count);
}
/* ------------------------------------
* pg_file_write_v1_1 - Version 1.1
*
* As of adminpack version 1.1, we no longer need to check if the user
* is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
* Users can then grant access to it based on their policies.
*
* Otherwise identical to pg_file_write (above).
*/
Datum
pg_file_write_v1_1(PG_FUNCTION_ARGS)
{
text *file = PG_GETARG_TEXT_PP(0);
text *data = PG_GETARG_TEXT_PP(1);
bool replace = PG_GETARG_BOOL(2);
int64 count = 0;
count = pg_file_write_internal(file, data, replace);
PG_RETURN_INT64(count);
}
/* ------------------------------------
* pg_file_write_internal - Workhorse for pg_file_write functions.
*
* This handles the actual work for pg_file_write.
*/
static int64
pg_file_write_internal(text *file, text *data, bool replace)
{
FILE *f;
char *filename;
int64 count = 0;
filename = convert_and_check_filename(file, false);
if (!replace)
{
struct stat fst;
if (stat(filename, &fst) >= 0)
ereport(ERROR,
(ERRCODE_DUPLICATE_FILE,
errmsg("file \"%s\" exists", filename)));
f = AllocateFile(filename, "wb");
}
else
f = AllocateFile(filename, "ab");
if (!f)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open file \"%s\" for writing: %m",
filename)));
count = fwrite(VARDATA_ANY(data), 1, VARSIZE_ANY_EXHDR(data), f);
if (count != VARSIZE_ANY_EXHDR(data) || FreeFile(f))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write file \"%s\": %m", filename)));
return (count);
}
/* ------------------------------------
* pg_file_rename - old version
*
* The superuser() check here must be kept as the library might be upgraded
* without the extension being upgraded, meaning that in pre-1.1 installations
* these functions could be called by any user.
*/
Datum
pg_file_rename(PG_FUNCTION_ARGS)
{
text *file1;
text *file2;
text *file3;
bool result;
requireSuperuser();
if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
PG_RETURN_NULL();
file1 = PG_GETARG_TEXT_PP(0);
file2 = PG_GETARG_TEXT_PP(1);
if (PG_ARGISNULL(2))
file3 = NULL;
else
file3 = PG_GETARG_TEXT_PP(2);
result = pg_file_rename_internal(file1, file2, file3);
PG_RETURN_BOOL(result);
}
/* ------------------------------------
* pg_file_rename_v1_1 - Version 1.1
*
* As of adminpack version 1.1, we no longer need to check if the user
* is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
* Users can then grant access to it based on their policies.
*
* Otherwise identical to pg_file_write (above).
*/
Datum
pg_file_rename_v1_1(PG_FUNCTION_ARGS)
{
text *file1;
text *file2;
text *file3;
bool result;
if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
PG_RETURN_NULL();
file1 = PG_GETARG_TEXT_PP(0);
file2 = PG_GETARG_TEXT_PP(1);
if (PG_ARGISNULL(2))
file3 = NULL;
else
file3 = PG_GETARG_TEXT_PP(2);
result = pg_file_rename_internal(file1, file2, file3);
PG_RETURN_BOOL(result);
}
/* ------------------------------------
* pg_file_rename_internal - Workhorse for pg_file_rename functions.
*
* This handles the actual work for pg_file_rename.
*/
static bool
pg_file_rename_internal(text *file1, text *file2, text *file3)
{
char *fn1,
*fn2,
*fn3;
int rc;
fn1 = convert_and_check_filename(file1, false);
fn2 = convert_and_check_filename(file2, false);
if (file3 == NULL)
fn3 = NULL;
else
fn3 = convert_and_check_filename(file3, false);
if (access(fn1, W_OK) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", fn1)));
return false;
}
if (fn3 && access(fn2, W_OK) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", fn2)));
return false;
}
rc = access(fn3 ? fn3 : fn2, W_OK);
if (rc >= 0 || errno != ENOENT)
{
ereport(ERROR,
(ERRCODE_DUPLICATE_FILE,
errmsg("cannot rename to target file \"%s\"",
fn3 ? fn3 : fn2)));
}
if (fn3)
{
if (rename(fn2, fn3) != 0)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not rename \"%s\" to \"%s\": %m",
fn2, fn3)));
}
if (rename(fn1, fn2) != 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not rename \"%s\" to \"%s\": %m",
fn1, fn2)));
if (rename(fn3, fn2) != 0)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not rename \"%s\" back to \"%s\": %m",
fn3, fn2)));
}
else
{
ereport(ERROR,
(ERRCODE_UNDEFINED_FILE,
errmsg("renaming \"%s\" to \"%s\" was reverted",
fn2, fn3)));
}
}
}
else if (rename(fn1, fn2) != 0)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not rename \"%s\" to \"%s\": %m", fn1, fn2)));
}
return true;
}
/* ------------------------------------
* pg_file_unlink - old version
*
* The superuser() check here must be kept as the library might be upgraded
* without the extension being upgraded, meaning that in pre-1.1 installations
* these functions could be called by any user.
*/
Datum
pg_file_unlink(PG_FUNCTION_ARGS)
{
char *filename;
requireSuperuser();
filename = convert_and_check_filename(PG_GETARG_TEXT_PP(0), false);
if (access(filename, W_OK) < 0)
{
if (errno == ENOENT)
PG_RETURN_BOOL(false);
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", filename)));
}
if (unlink(filename) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not unlink file \"%s\": %m", filename)));
PG_RETURN_BOOL(false);
}
PG_RETURN_BOOL(true);
}
/* ------------------------------------
* pg_file_unlink_v1_1 - Version 1.1
*
* As of adminpack version 1.1, we no longer need to check if the user
* is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
* Users can then grant access to it based on their policies.
*
* Otherwise identical to pg_file_unlink (above).
*/
Datum
pg_file_unlink_v1_1(PG_FUNCTION_ARGS)
{
char *filename;
filename = convert_and_check_filename(PG_GETARG_TEXT_PP(0), false);
if (access(filename, W_OK) < 0)
{
if (errno == ENOENT)
PG_RETURN_BOOL(false);
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", filename)));
}
if (unlink(filename) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not unlink file \"%s\": %m", filename)));
PG_RETURN_BOOL(false);
}
PG_RETURN_BOOL(true);
}
/* ------------------------------------
* pg_logdir_ls - Old version
*
* The superuser() check here must be kept as the library might be upgraded
* without the extension being upgraded, meaning that in pre-1.1 installations
* these functions could be called by any user.
*/
Datum
pg_logdir_ls(PG_FUNCTION_ARGS)
{
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("only superuser can list the log directory"))));
return (pg_logdir_ls_internal(fcinfo));
}
/* ------------------------------------
* pg_logdir_ls_v1_1 - Version 1.1
*
* As of adminpack version 1.1, we no longer need to check if the user
* is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
* Users can then grant access to it based on their policies.
*
* Otherwise identical to pg_logdir_ls (above).
*/
Datum
pg_logdir_ls_v1_1(PG_FUNCTION_ARGS)
{
return (pg_logdir_ls_internal(fcinfo));
}
static Datum
pg_logdir_ls_internal(FunctionCallInfo fcinfo)
{
FuncCallContext *funcctx;
struct dirent *de;
directory_fctx *fctx;
if (strcmp(Log_filename, "postgresql-%Y-%m-%d_%H%M%S.log") != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
(errmsg("the log_filename parameter must equal 'postgresql-%%Y-%%m-%%d_%%H%%M%%S.log'"))));
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
TupleDesc tupdesc;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
fctx = palloc(sizeof(directory_fctx));
tupdesc = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starttime",
TIMESTAMPOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "filename",
TEXTOID, -1, 0);
funcctx->attinmeta = TupleDescGetAttInMetadata(tupdesc);
fctx->location = pstrdup(Log_directory);
fctx->dirdesc = AllocateDir(fctx->location);
if (!fctx->dirdesc)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m",
fctx->location)));
funcctx->user_fctx = fctx;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
fctx = (directory_fctx *) funcctx->user_fctx;
while ((de = ReadDir(fctx->dirdesc, fctx->location)) != NULL)
{
char *values[2];
HeapTuple tuple;
char timestampbuf[32];
char *field[MAXDATEFIELDS];
char lowstr[MAXDATELEN + 1];
int dtype;
int nf,
ftype[MAXDATEFIELDS];
fsec_t fsec;
int tz = 0;
struct pg_tm date;
/*
* Default format: postgresql-YYYY-MM-DD_HHMMSS.log
*/
if (strlen(de->d_name) != 32
|| strncmp(de->d_name, "postgresql-", 11) != 0
|| de->d_name[21] != '_'
|| strcmp(de->d_name + 28, ".log") != 0)
continue;
/* extract timestamp portion of filename */
strcpy(timestampbuf, de->d_name + 11);
timestampbuf[17] = '\0';
/* parse and decode expected timestamp to verify it's OK format */
if (ParseDateTime(timestampbuf, lowstr, MAXDATELEN, field, ftype, MAXDATEFIELDS, &nf))
continue;
if (DecodeDateTime(field, ftype, nf, &dtype, &date, &fsec, &tz))
continue;
/* Seems the timestamp is OK; prepare and return tuple */
values[0] = timestampbuf;
values[1] = psprintf("%s/%s", fctx->location, de->d_name);
tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
}
FreeDir(fctx->dirdesc);
SRF_RETURN_DONE(funcctx);
}