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345bf97b80a0d45b1fc1a0d921d059a782f06db8
postgres/contrib/adminpack/adminpack.c
Noah Misch e03c6d93bf Fix pg_file_write() error handling. 
Detect fclose() failures; given "ln -s /dev/full $PGDATA/devfull",
"pg_file_write('devfull', 'x', true)" now fails as it should.  Don't
leak a stream when fwrite() fails.  Remove a born-ineffective test that
aimed to skip zero-length writes.  Back-patch to 9.2 (all supported
versions).
2017-03-12 19:36:15 -04:00

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8.5 KiB
C
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/*-------------------------------------------------------------------------
*
* adminpack.c
*
*
* Copyright (c) 2002-2013, 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_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;
Datum pg_file_write(PG_FUNCTION_ARGS);
Datum pg_file_rename(PG_FUNCTION_ARGS);
Datum pg_file_unlink(PG_FUNCTION_ARGS);
Datum pg_logdir_ls(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(pg_file_write);
PG_FUNCTION_INFO_V1(pg_file_rename);
PG_FUNCTION_INFO_V1(pg_file_unlink);
PG_FUNCTION_INFO_V1(pg_logdir_ls);
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 */
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"))));
}
/* ------------------------------------
* generic file handling functions
*/
Datum
pg_file_write(PG_FUNCTION_ARGS)
{
FILE *f;
char *filename;
text *data;
int64 count = 0;
requireSuperuser();
filename = convert_and_check_filename(PG_GETARG_TEXT_P(0), false);
data = PG_GETARG_TEXT_P(1);
if (!PG_GETARG_BOOL(2))
{
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(data), 1, VARSIZE(data) - VARHDRSZ, f);
if (count != VARSIZE(data) - VARHDRSZ || FreeFile(f))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write file \"%s\": %m", filename)));
PG_RETURN_INT64(count);
}
Datum
pg_file_rename(PG_FUNCTION_ARGS)
{
char *fn1,
*fn2,
*fn3;
int rc;
requireSuperuser();
if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
PG_RETURN_NULL();
fn1 = convert_and_check_filename(PG_GETARG_TEXT_P(0), false);
fn2 = convert_and_check_filename(PG_GETARG_TEXT_P(1), false);
if (PG_ARGISNULL(2))
fn3 = 0;
else
fn3 = convert_and_check_filename(PG_GETARG_TEXT_P(2), false);
if (access(fn1, W_OK) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", fn1)));
PG_RETURN_BOOL(false);
}
if (fn3 && access(fn2, W_OK) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", fn2)));
PG_RETURN_BOOL(false);
}
rc = access(fn3 ? fn3 : fn2, 2);
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)));
}
PG_RETURN_BOOL(true);
}
Datum
pg_file_unlink(PG_FUNCTION_ARGS)
{
char *filename;
requireSuperuser();
filename = convert_and_check_filename(PG_GETARG_TEXT_P(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);
}
Datum
pg_logdir_ls(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
struct dirent *de;
directory_fctx *fctx;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("only superuser can list the log directory"))));
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 read 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] = palloc(strlen(fctx->location) + strlen(de->d_name) + 2);
sprintf(values[1], "%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);
}
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