| /* Common code for file-based databases in nss_files module. |
| Copyright (C) 1996-2014 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 <bits/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 shared stream open on the database file. */ |
| |
| static FILE *stream; |
| static fpos_t position; |
| static enum { nouse, getent, getby } last_use; |
| static int keep_stream; |
| |
| /* Open database file if not already opened. */ |
| static enum nss_status |
| internal_setent (int stayopen) |
| { |
| 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); |
| |
| /* Remember STAYOPEN flag. */ |
| if (stream != NULL) |
| keep_stream |= stayopen; |
| |
| 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 (1); |
| |
| if (status == NSS_STATUS_SUCCESS && fgetpos (stream, &position) < 0) |
| { |
| fclose (stream); |
| stream = NULL; |
| status = NSS_STATUS_UNAVAIL; |
| } |
| |
| last_use = getent; |
| |
| __libc_lock_unlock (lock); |
| |
| return status; |
| } |
| |
| |
| /* Close the database file. */ |
| static void |
| internal_endent (void) |
| { |
| 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 (); |
| |
| /* Reset STAYOPEN flag. */ |
| keep_stream = 0; |
| |
| __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 (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 (__builtin_expect (parse_result == -1, 0)) |
| { |
| 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 (0); |
| |
| __set_errno (save_errno); |
| |
| if (status == NSS_STATUS_SUCCESS && fgetpos (stream, &position) < 0) |
| { |
| fclose (stream); |
| stream = NULL; |
| status = NSS_STATUS_UNAVAIL; |
| } |
| } |
| |
| if (status == NSS_STATUS_SUCCESS) |
| { |
| /* If the last use was not by the getent function we need the |
| position the stream. */ |
| if (last_use != getent) |
| { |
| if (fsetpos (stream, &position) < 0) |
| status = NSS_STATUS_UNAVAIL; |
| else |
| last_use = getent; |
| } |
| |
| if (status == NSS_STATUS_SUCCESS) |
| { |
| status = internal_getent (result, buffer, buflen, errnop |
| H_ERRNO_ARG EXTRA_ARGS_VALUE); |
| |
| /* Remember this position if we were successful. If the |
| operation failed we give the user a chance to repeat the |
| operation (perhaps the buffer was too small). */ |
| if (status == NSS_STATUS_SUCCESS) |
| fgetpos (stream, &position); |
| else |
| /* We must make sure we reposition the stream the next call. */ |
| last_use = nouse; |
| } |
| } |
| |
| __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; \ |
| \ |
| __libc_lock_lock (lock); \ |
| \ |
| /* Reset file pointer to beginning or open file. */ \ |
| status = internal_setent (keep_stream); \ |
| \ |
| if (status == NSS_STATUS_SUCCESS) \ |
| { \ |
| /* Tell getent function that we have repositioned the file pointer. */ \ |
| last_use = getby; \ |
| \ |
| while ((status = internal_getent (result, buffer, buflen, errnop \ |
| H_ERRNO_ARG EXTRA_ARGS_VALUE)) \ |
| == NSS_STATUS_SUCCESS) \ |
| { break_if_match } \ |
| \ |
| if (! keep_stream) \ |
| internal_endent (); \ |
| } \ |
| \ |
| __libc_lock_unlock (lock); \ |
| \ |
| return status; \ |
| } |