mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 13:00:06 +00:00
336 lines
8.5 KiB
C
336 lines
8.5 KiB
C
/* Common code for file-based databases in nss_files module.
|
||
Copyright (C) 1996-2017 Free Software Foundation, Inc.
|
||
This file is part of the GNU C Library.
|
||
|
||
The GNU C Library is free software; you can redistribute it and/or
|
||
modify it under the terms of the GNU Lesser General Public
|
||
License as published by the Free Software Foundation; either
|
||
version 2.1 of the License, or (at your option) any later version.
|
||
|
||
The GNU C Library is distributed in the hope that it will be useful,
|
||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
Lesser General Public License for more details.
|
||
|
||
You should have received a copy of the GNU Lesser General Public
|
||
License along with the GNU C Library; if not, see
|
||
<http://www.gnu.org/licenses/>. */
|
||
|
||
#include <stdio.h>
|
||
#include <ctype.h>
|
||
#include <errno.h>
|
||
#include <fcntl.h>
|
||
#include <libc-lock.h>
|
||
#include "nsswitch.h"
|
||
|
||
#include <kernel-features.h>
|
||
|
||
/* These symbols are defined by the including source file:
|
||
|
||
ENTNAME -- database name of the structure and functions (hostent, pwent).
|
||
STRUCTURE -- struct name, define only if not ENTNAME (passwd, group).
|
||
DATABASE -- string of the database file's name ("hosts", "passwd").
|
||
|
||
NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
|
||
|
||
Also see files-parse.c.
|
||
*/
|
||
|
||
#define ENTNAME_r CONCAT(ENTNAME,_r)
|
||
|
||
#define DATAFILE "/etc/" DATABASE
|
||
|
||
#ifdef NEED_H_ERRNO
|
||
# include <netdb.h>
|
||
# define H_ERRNO_PROTO , int *herrnop
|
||
# define H_ERRNO_ARG , herrnop
|
||
# define H_ERRNO_SET(val) (*herrnop = (val))
|
||
#else
|
||
# define H_ERRNO_PROTO
|
||
# define H_ERRNO_ARG
|
||
# define H_ERRNO_SET(val) ((void) 0)
|
||
#endif
|
||
|
||
#ifndef EXTRA_ARGS
|
||
# define EXTRA_ARGS
|
||
# define EXTRA_ARGS_DECL
|
||
# define EXTRA_ARGS_VALUE
|
||
#endif
|
||
|
||
/* Locks the static variables in this file. */
|
||
__libc_lock_define_initialized (static, lock)
|
||
|
||
/* Maintenance of the stream open on the database file. For getXXent
|
||
operations the stream needs to be held open across calls, the other
|
||
getXXbyYY operations all use their own stream. */
|
||
|
||
static FILE *stream;
|
||
|
||
/* Open database file if not already opened. */
|
||
static enum nss_status
|
||
internal_setent (FILE **stream)
|
||
{
|
||
enum nss_status status = NSS_STATUS_SUCCESS;
|
||
|
||
if (*stream == NULL)
|
||
{
|
||
*stream = fopen (DATAFILE, "rce");
|
||
|
||
if (*stream == NULL)
|
||
status = errno == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
|
||
else
|
||
{
|
||
#if !defined O_CLOEXEC || !defined __ASSUME_O_CLOEXEC
|
||
# ifdef O_CLOEXEC
|
||
if (__have_o_cloexec <= 0)
|
||
# endif
|
||
{
|
||
/* We have to make sure the file is `closed on exec'. */
|
||
int result;
|
||
int flags;
|
||
|
||
result = flags = fcntl (fileno (*stream), F_GETFD, 0);
|
||
if (result >= 0)
|
||
{
|
||
# ifdef O_CLOEXEC
|
||
if (__have_o_cloexec == 0)
|
||
__have_o_cloexec = (flags & FD_CLOEXEC) == 0 ? -1 : 1;
|
||
if (__have_o_cloexec < 0)
|
||
# endif
|
||
{
|
||
flags |= FD_CLOEXEC;
|
||
result = fcntl (fileno (*stream), F_SETFD, flags);
|
||
}
|
||
}
|
||
if (result < 0)
|
||
{
|
||
/* Something went wrong. Close the stream and return a
|
||
failure. */
|
||
fclose (*stream);
|
||
*stream = NULL;
|
||
status = NSS_STATUS_UNAVAIL;
|
||
}
|
||
}
|
||
#endif
|
||
}
|
||
}
|
||
else
|
||
rewind (*stream);
|
||
|
||
return status;
|
||
}
|
||
|
||
|
||
/* Thread-safe, exported version of that. */
|
||
enum nss_status
|
||
CONCAT(_nss_files_set,ENTNAME) (int stayopen)
|
||
{
|
||
enum nss_status status;
|
||
|
||
__libc_lock_lock (lock);
|
||
|
||
status = internal_setent (&stream);
|
||
|
||
__libc_lock_unlock (lock);
|
||
|
||
return status;
|
||
}
|
||
|
||
|
||
/* Close the database file. */
|
||
static void
|
||
internal_endent (FILE **stream)
|
||
{
|
||
if (*stream != NULL)
|
||
{
|
||
fclose (*stream);
|
||
*stream = NULL;
|
||
}
|
||
}
|
||
|
||
|
||
/* Thread-safe, exported version of that. */
|
||
enum nss_status
|
||
CONCAT(_nss_files_end,ENTNAME) (void)
|
||
{
|
||
__libc_lock_lock (lock);
|
||
|
||
internal_endent (&stream);
|
||
|
||
__libc_lock_unlock (lock);
|
||
|
||
return NSS_STATUS_SUCCESS;
|
||
}
|
||
|
||
|
||
typedef enum
|
||
{
|
||
gcr_ok = 0,
|
||
gcr_error = -1,
|
||
gcr_overflow = -2
|
||
} get_contents_ret;
|
||
|
||
/* Hack around the fact that fgets only accepts int sizes. */
|
||
static get_contents_ret
|
||
get_contents (char *linebuf, size_t len, FILE *stream)
|
||
{
|
||
size_t remaining_len = len;
|
||
char *curbuf = linebuf;
|
||
|
||
do
|
||
{
|
||
int curlen = ((remaining_len > (size_t) INT_MAX) ? INT_MAX
|
||
: remaining_len);
|
||
|
||
/* Terminate the line so that we can test for overflow. */
|
||
((unsigned char *) curbuf)[curlen - 1] = 0xff;
|
||
|
||
char *p = fgets_unlocked (curbuf, curlen, stream);
|
||
|
||
/* EOF or read error. */
|
||
if (p == NULL)
|
||
return gcr_error;
|
||
|
||
/* Done reading in the line. */
|
||
if (((unsigned char *) curbuf)[curlen - 1] == 0xff)
|
||
return gcr_ok;
|
||
|
||
/* Drop the terminating '\0'. */
|
||
remaining_len -= curlen - 1;
|
||
curbuf += curlen - 1;
|
||
}
|
||
/* fgets copies one less than the input length. Our last iteration is of
|
||
REMAINING_LEN and once that is done, REMAINING_LEN is decremented by
|
||
REMAINING_LEN - 1, leaving the result as 1. */
|
||
while (remaining_len > 1);
|
||
|
||
/* This means that the current buffer was not large enough. */
|
||
return gcr_overflow;
|
||
}
|
||
|
||
/* Parsing the database file into `struct STRUCTURE' data structures. */
|
||
static enum nss_status
|
||
internal_getent (FILE *stream, struct STRUCTURE *result,
|
||
char *buffer, size_t buflen, int *errnop H_ERRNO_PROTO
|
||
EXTRA_ARGS_DECL)
|
||
{
|
||
char *p;
|
||
struct parser_data *data = (void *) buffer;
|
||
size_t linebuflen = buffer + buflen - data->linebuffer;
|
||
int parse_result;
|
||
|
||
if (buflen < sizeof *data + 2)
|
||
{
|
||
*errnop = ERANGE;
|
||
H_ERRNO_SET (NETDB_INTERNAL);
|
||
return NSS_STATUS_TRYAGAIN;
|
||
}
|
||
|
||
do
|
||
{
|
||
get_contents_ret r = get_contents (data->linebuffer, linebuflen, stream);
|
||
|
||
if (r == gcr_error)
|
||
{
|
||
/* End of file or read error. */
|
||
H_ERRNO_SET (HOST_NOT_FOUND);
|
||
return NSS_STATUS_NOTFOUND;
|
||
}
|
||
|
||
if (r == gcr_overflow)
|
||
{
|
||
/* The line is too long. Give the user the opportunity to
|
||
enlarge the buffer. */
|
||
*errnop = ERANGE;
|
||
H_ERRNO_SET (NETDB_INTERNAL);
|
||
return NSS_STATUS_TRYAGAIN;
|
||
}
|
||
|
||
/* Everything OK. Now skip leading blanks. */
|
||
p = data->linebuffer;
|
||
while (isspace (*p))
|
||
++p;
|
||
}
|
||
while (*p == '\0' || *p == '#' /* Ignore empty and comment lines. */
|
||
/* Parse the line. If it is invalid, loop to get the next
|
||
line of the file to parse. */
|
||
|| ! (parse_result = parse_line (p, result, data, buflen, errnop
|
||
EXTRA_ARGS)));
|
||
|
||
if (__glibc_unlikely (parse_result == -1))
|
||
{
|
||
H_ERRNO_SET (NETDB_INTERNAL);
|
||
return NSS_STATUS_TRYAGAIN;
|
||
}
|
||
|
||
/* Filled in RESULT with the next entry from the database file. */
|
||
return NSS_STATUS_SUCCESS;
|
||
}
|
||
|
||
|
||
/* Return the next entry from the database file, doing locking. */
|
||
enum nss_status
|
||
CONCAT(_nss_files_get,ENTNAME_r) (struct STRUCTURE *result, char *buffer,
|
||
size_t buflen, int *errnop H_ERRNO_PROTO)
|
||
{
|
||
/* Return next entry in host file. */
|
||
enum nss_status status = NSS_STATUS_SUCCESS;
|
||
|
||
__libc_lock_lock (lock);
|
||
|
||
/* Be prepared that the set*ent function was not called before. */
|
||
if (stream == NULL)
|
||
{
|
||
int save_errno = errno;
|
||
|
||
status = internal_setent (&stream);
|
||
|
||
__set_errno (save_errno);
|
||
}
|
||
|
||
if (status == NSS_STATUS_SUCCESS)
|
||
status = internal_getent (stream, result, buffer, buflen, errnop
|
||
H_ERRNO_ARG EXTRA_ARGS_VALUE);
|
||
|
||
__libc_lock_unlock (lock);
|
||
|
||
return status;
|
||
}
|
||
|
||
/* Macro for defining lookup functions for this file-based database.
|
||
|
||
NAME is the name of the lookup; e.g. `hostbyname'.
|
||
|
||
DB_CHAR, KEYPATTERN, KEYSIZE are ignored here but used by db-XXX.c
|
||
e.g. `1 + sizeof (id) * 4'.
|
||
|
||
PROTO is the potentially empty list of other parameters.
|
||
|
||
BREAK_IF_MATCH is a block of code which compares `struct STRUCTURE *result'
|
||
to the lookup key arguments and does `break;' if they match. */
|
||
|
||
#define DB_LOOKUP(name, db_char, keysize, keypattern, break_if_match, proto...)\
|
||
enum nss_status \
|
||
_nss_files_get##name##_r (proto, \
|
||
struct STRUCTURE *result, char *buffer, \
|
||
size_t buflen, int *errnop H_ERRNO_PROTO) \
|
||
{ \
|
||
enum nss_status status; \
|
||
FILE *stream = NULL; \
|
||
\
|
||
/* Open file. */ \
|
||
status = internal_setent (&stream); \
|
||
\
|
||
if (status == NSS_STATUS_SUCCESS) \
|
||
{ \
|
||
while ((status = internal_getent (stream, result, buffer, buflen, errnop \
|
||
H_ERRNO_ARG EXTRA_ARGS_VALUE)) \
|
||
== NSS_STATUS_SUCCESS) \
|
||
{ break_if_match } \
|
||
\
|
||
internal_endent (&stream); \
|
||
} \
|
||
\
|
||
return status; \
|
||
}
|