YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

/*-------------------------------------------------------------------------

 *

 * genfile.c

 *    Functions for direct access to files

 *

 *

 * Copyright (c) 2004-2018, PostgreSQL Global Development Group

 *

 * Author: Andreas Pflug <pgadmin@pse-consulting.de>

 *

 * IDENTIFICATION

 *    src/backend/utils/adt/genfile.c

 *

 *-------------------------------------------------------------------------

 */

#include "postgres.h"

#include <sys/file.h>

#include <sys/stat.h>

#include <unistd.h>

#include <dirent.h>

#include "access/htup_details.h"

#include "access/xlog_internal.h"

#include "catalog/pg_authid.h"

#include "catalog/pg_type.h"

#include "funcapi.h"

#include "mb/pg_wchar.h"

#include "miscadmin.h"

#include "postmaster/syslogger.h"

#include "storage/fd.h"

#include "utils/builtins.h"

#include "utils/memutils.h"

#include "utils/timestamp.h"

typedef struct

{

  char     *location;

  DIR      *dirdesc;

  bool    include_dot_dirs;

} directory_fctx;

/*

 * 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.

 *

 * This does a privilege check against the 'pg_read_server_files' role, so

 * this function is really only appropriate for callers who are only checking

 * 'read' access.  Do not use this function if you are looking for a check

 * for 'write' or 'program' access without updating it to access the type

 * of check as an argument and checking the appropriate role membership.

 */

static char *

convert_and_check_filename(text *arg)

{

  char     *filename;

  filename = text_to_cstring(arg);

  canonicalize_path(filename);  /* filename can change length here */

  /*

   * Members of the 'pg_read_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_READ_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) &&

      (!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;

}

/*

 * Read a section of a file, returning it as bytea

 *

 * Caller is responsible for all permissions checking.

 *

 * We read the whole of the file when bytes_to_read is negative.

 */

static bytea *

read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read,

         bool missing_ok)

{

  bytea    *buf;

  size_t    nbytes;

  FILE     *file;

  if (bytes_to_read < 0)

  {

    if (seek_offset < 0)

      bytes_to_read = -seek_offset;

    else

    {

      struct stat fst;

      if (stat(filename, &fst) < 0)

      {

        if (missing_ok && errno == ENOENT)

          return NULL;

        else

          ereport(ERROR,

              (errcode_for_file_access(),

               errmsg("could not stat file \"%s\": %m", filename)));

      }

      bytes_to_read = fst.st_size - seek_offset;

    }

  }

  /* not sure why anyone thought that int64 length was a good idea */

  if (bytes_to_read > (MaxAllocSize - VARHDRSZ))

    ereport(ERROR,

        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),

         errmsg("requested length too large")));

  if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)

  {

    if (missing_ok && errno == ENOENT)

      return NULL;

    else

      ereport(ERROR,

          (errcode_for_file_access(),

           errmsg("could not open file \"%s\" for reading: %m",

              filename)));

  }

  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)));

  buf = (bytea *) palloc((Size) bytes_to_read + VARHDRSZ);

  nbytes = fread(VARDATA(buf), 1, (size_t) bytes_to_read, file);

  if (ferror(file))

    ereport(ERROR,

        (errcode_for_file_access(),

         errmsg("could not read file \"%s\": %m", filename)));

  SET_VARSIZE(buf, nbytes + VARHDRSZ);

  FreeFile(file);

  return buf;

}

/*

 * Similar to read_binary_file, but we verify that the contents are valid

 * in the database encoding.

 */

static text *

read_text_file(const char *filename, int64 seek_offset, int64 bytes_to_read,

         bool missing_ok)

{

  bytea    *buf;

  buf = read_binary_file(filename, seek_offset, bytes_to_read, missing_ok);

  if (buf != NULL)

  {

    /* Make sure the input is valid */

    pg_verifymbstr(VARDATA(buf), VARSIZE(buf) - VARHDRSZ, false);

    /* OK, we can cast it to text safely */

    return (text *) buf;

  }

  else

    return NULL;

}

/*

 * Read a section of a file, returning it as text

 *

 * This function is kept to support adminpack 1.0.

 */

Datum

pg_read_file(PG_FUNCTION_ARGS)

{

  text     *filename_t = PG_GETARG_TEXT_PP(0);

  int64   seek_offset = 0;

  int64   bytes_to_read = -1;

  bool    missing_ok = false;

  char     *filename;

  text     *result;

  if (!superuser())

    ereport(ERROR,

        (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),

         (errmsg("must be superuser to read files with adminpack 1.0"),

          errhint("Consider using pg_file_read(), which is part of core, instead."))));

  /* handle optional arguments */

  if (PG_NARGS() >= 3)

  {

    seek_offset = PG_GETARG_INT64(1);

    bytes_to_read = PG_GETARG_INT64(2);

    if (bytes_to_read < 0)

      ereport(ERROR,

          (errcode(ERRCODE_INVALID_PARAMETER_VALUE),

           errmsg("requested length cannot be negative")));

  }

  if (PG_NARGS() >= 4)

    missing_ok = PG_GETARG_BOOL(3);

  filename = convert_and_check_filename(filename_t);

  result = read_text_file(filename, seek_offset, bytes_to_read, missing_ok);

  if (result)

    PG_RETURN_TEXT_P(result);

  else

    PG_RETURN_NULL();

}

/*

 * Read a section of a file, returning it as text

 *

 * No superuser check done here- instead privileges are handled by the

 * GRANT system.

 */

Datum

pg_read_file_v2(PG_FUNCTION_ARGS)

{

  text     *filename_t = PG_GETARG_TEXT_PP(0);

  int64   seek_offset = 0;

  int64   bytes_to_read = -1;

  bool    missing_ok = false;

  char     *filename;

  text     *result;

  /* handle optional arguments */

  if (PG_NARGS() >= 3)

  {

    seek_offset = PG_GETARG_INT64(1);

    bytes_to_read = PG_GETARG_INT64(2);

    if (bytes_to_read < 0)

      ereport(ERROR,

          (errcode(ERRCODE_INVALID_PARAMETER_VALUE),

           errmsg("requested length cannot be negative")));

  }

  if (PG_NARGS() >= 4)

    missing_ok = PG_GETARG_BOOL(3);

  filename = convert_and_check_filename(filename_t);

  result = read_text_file(filename, seek_offset, bytes_to_read, missing_ok);

  if (result)

    PG_RETURN_TEXT_P(result);

  else

    PG_RETURN_NULL();

}

/*

 * Read a section of a file, returning it as bytea

 */

Datum

pg_read_binary_file(PG_FUNCTION_ARGS)

{

  text     *filename_t = PG_GETARG_TEXT_PP(0);

  int64   seek_offset = 0;

  int64   bytes_to_read = -1;

  bool    missing_ok = false;

  char     *filename;

  bytea    *result;

  /* handle optional arguments */

  if (PG_NARGS() >= 3)

  {

    seek_offset = PG_GETARG_INT64(1);

    bytes_to_read = PG_GETARG_INT64(2);

    if (bytes_to_read < 0)

      ereport(ERROR,

          (errcode(ERRCODE_INVALID_PARAMETER_VALUE),

           errmsg("requested length cannot be negative")));

  }

  if (PG_NARGS() >= 4)

    missing_ok = PG_GETARG_BOOL(3);

  filename = convert_and_check_filename(filename_t);

  result = read_binary_file(filename, seek_offset,

                bytes_to_read, missing_ok);

  if (result)

    PG_RETURN_BYTEA_P(result);

  else

    PG_RETURN_NULL();

}

/*

 * Wrapper functions for the 1 and 3 argument variants of pg_read_file_v2()

 * and pg_binary_read_file().

 *

 * These are necessary to pass the sanity check in opr_sanity, which checks

 * that all built-in functions that share the implementing C function take

 * the same number of arguments.

 */

Datum

pg_read_file_off_len(PG_FUNCTION_ARGS)

{

  return pg_read_file_v2(fcinfo);

}

Datum

pg_read_file_all(PG_FUNCTION_ARGS)

{

  return pg_read_file_v2(fcinfo);

}

Datum

pg_read_binary_file_off_len(PG_FUNCTION_ARGS)

{

  return pg_read_binary_file(fcinfo);

}

Datum

pg_read_binary_file_all(PG_FUNCTION_ARGS)

{

  return pg_read_binary_file(fcinfo);

}

/*

 * stat a file

 */

Datum

pg_stat_file(PG_FUNCTION_ARGS)

{

  text     *filename_t = PG_GETARG_TEXT_PP(0);

  char     *filename;

  struct stat fst;

  Datum   values[6];

  bool    isnull[6];

  HeapTuple tuple;

  TupleDesc tupdesc;

  bool    missing_ok = false;

  /* check the optional argument */

  if (PG_NARGS() == 2)

    missing_ok = PG_GETARG_BOOL(1);

  filename = convert_and_check_filename(filename_t);

  if (stat(filename, &fst) < 0)

  {

    if (missing_ok && errno == ENOENT)

      PG_RETURN_NULL();

    else

      ereport(ERROR,

          (errcode_for_file_access(),

           errmsg("could not stat file \"%s\": %m", filename)));

  }

  /*

   * This record type had better match the output parameters declared for me

   * in pg_proc.h.

   */

  tupdesc = CreateTemplateTupleDesc(6, false);

  TupleDescInitEntry(tupdesc, (AttrNumber) 1,

             "size", INT8OID, -1, 0);

  TupleDescInitEntry(tupdesc, (AttrNumber) 2,

             "access", TIMESTAMPTZOID, -1, 0);

  TupleDescInitEntry(tupdesc, (AttrNumber) 3,

             "modification", TIMESTAMPTZOID, -1, 0);

  TupleDescInitEntry(tupdesc, (AttrNumber) 4,

             "change", TIMESTAMPTZOID, -1, 0);

  TupleDescInitEntry(tupdesc, (AttrNumber) 5,

             "creation", TIMESTAMPTZOID, -1, 0);

  TupleDescInitEntry(tupdesc, (AttrNumber) 6,

             "isdir", BOOLOID, -1, 0);

  BlessTupleDesc(tupdesc);

  memset(isnull, false, sizeof(isnull));

  values[0] = Int64GetDatum((int64) fst.st_size);

  values[1] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_atime));

  values[2] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_mtime));

  /* Unix has file status change time, while Win32 has creation time */

#if !defined(WIN32) && !defined(__CYGWIN__)

  values[3] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));

  isnull[4] = true;

#else

  isnull[3] = true;

  values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));

#endif

  values[5] = BoolGetDatum(S_ISDIR(fst.st_mode));

  tuple = heap_form_tuple(tupdesc, values, isnull);

  pfree(filename);

  PG_RETURN_DATUM(HeapTupleGetDatum(tuple));

}

/*

 * stat a file (1 argument version)

 *

 * note: this wrapper is necessary to pass the sanity check in opr_sanity,

 * which checks that all built-in functions that share the implementing C

 * function take the same number of arguments

 */

Datum

pg_stat_file_1arg(PG_FUNCTION_ARGS)

{

  return pg_stat_file(fcinfo);

}

/*

 * List a directory (returns the filenames only)

 */

Datum

pg_ls_dir(PG_FUNCTION_ARGS)

{

  FuncCallContext *funcctx;

  struct dirent *de;

  directory_fctx *fctx;

  MemoryContext oldcontext;

  if (SRF_IS_FIRSTCALL())

  {

    bool    missing_ok = false;

    bool    include_dot_dirs = false;

    /* check the optional arguments */

    if (PG_NARGS() == 3)

    {

      if (!PG_ARGISNULL(1))

        missing_ok = PG_GETARG_BOOL(1);

      if (!PG_ARGISNULL(2))

        include_dot_dirs = PG_GETARG_BOOL(2);

    }

    funcctx = SRF_FIRSTCALL_INIT();

    oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

    fctx = palloc(sizeof(directory_fctx));

    fctx->location = convert_and_check_filename(PG_GETARG_TEXT_PP(0));

    fctx->include_dot_dirs = include_dot_dirs;

    fctx->dirdesc = AllocateDir(fctx->location);

    if (!fctx->dirdesc)

    {

      if (missing_ok && errno == ENOENT)

      {

        MemoryContextSwitchTo(oldcontext);

        SRF_RETURN_DONE(funcctx);

      }

      else

        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)

  {

    if (!fctx->include_dot_dirs &&

      (strcmp(de->d_name, ".") == 0 ||

       strcmp(de->d_name, "..") == 0))

      continue;

    SRF_RETURN_NEXT(funcctx, CStringGetTextDatum(de->d_name));

  }

  FreeDir(fctx->dirdesc);

  SRF_RETURN_DONE(funcctx);

}

/*

 * List a directory (1 argument version)

 *

 * note: this wrapper is necessary to pass the sanity check in opr_sanity,

 * which checks that all built-in functions that share the implementing C

 * function take the same number of arguments.

 */

Datum

pg_ls_dir_1arg(PG_FUNCTION_ARGS)

{

  return pg_ls_dir(fcinfo);

}

/* Generic function to return a directory listing of files */

static Datum

pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir)

{

  FuncCallContext *funcctx;

  struct dirent *de;

  directory_fctx *fctx;

  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(3, false);

    TupleDescInitEntry(tupdesc, (AttrNumber) 1, "name",

               TEXTOID, -1, 0);

    TupleDescInitEntry(tupdesc, (AttrNumber) 2, "size",

               INT8OID, -1, 0);

    TupleDescInitEntry(tupdesc, (AttrNumber) 3, "modification",

               TIMESTAMPTZOID, -1, 0);

    funcctx->tuple_desc = BlessTupleDesc(tupdesc);

    fctx->location = pstrdup(dir);

    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)

  {

    Datum   values[3];

    bool    nulls[3];

    char    path[MAXPGPATH * 2];

    struct stat attrib;

    HeapTuple tuple;

    /* Skip hidden files */

    if (de->d_name[0] == '.')

      continue;

    /* Get the file info */

    snprintf(path, sizeof(path), "%s/%s", fctx->location, de->d_name);

    if (stat(path, &attrib) < 0)

      ereport(ERROR,

          (errcode_for_file_access(),

           errmsg("could not stat directory \"%s\": %m", dir)));

    /* Ignore anything but regular files */

    if (!S_ISREG(attrib.st_mode))

      continue;

    values[0] = CStringGetTextDatum(de->d_name);

    values[1] = Int64GetDatum((int64) attrib.st_size);

    values[2] = TimestampTzGetDatum(time_t_to_timestamptz(attrib.st_mtime));

    memset(nulls, 0, sizeof(nulls));

    tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);

    SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));

  }

  FreeDir(fctx->dirdesc);

  SRF_RETURN_DONE(funcctx);

}

/* Function to return the list of files in the log directory */

Datum

pg_ls_logdir(PG_FUNCTION_ARGS)

{

  return pg_ls_dir_files(fcinfo, Log_directory);

}

/* Function to return the list of files in the WAL directory */

Datum

pg_ls_waldir(PG_FUNCTION_ARGS)

{

  return pg_ls_dir_files(fcinfo, XLOGDIR);

}