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9980bf0b30
glibc/nss/nss_files/files-parse.c
Florian Weimer 9980bf0b30 nss_files: Use generic result pointer in parse_line 
As a result, all parse_line functions have the same prototype, except
for that producing struct hostent.  This change is ABI-compatible, so
it does not alter the internal GLIBC_PRIVATE ABI (otherwise we should
probably have renamed the exported functions).

A future change will use this to implement a generict fget*ent_r
function.

Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2020-07-21 07:33:33 +02:00

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/* Common code for file-based database parsers in nss_files module.
Copyright (C) 1996-2020 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
<https://www.gnu.org/licenses/>. */
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <nss_files.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").
ENTDATA -- if defined, `struct ENTDATA' is used by the parser to store
things pointed to by the resultant `struct STRUCTURE'.
NEED_H_ERRNO - defined iff an arg `int *herrnop' is used.
EXTRA_ARGS -- defined iff extra parameters must be passed to the parser
EXTRA_ARGS_DECL -- declaration for these extra parameters
EXTRA_ARGS_VALUE -- values to be passed for these parameters
Also see files-XXX.c. */
#ifndef EXTRA_ARGS
# define EXTRA_ARGS
# define EXTRA_ARGS_DECL
# define EXTRA_ARGS_VALUE
#endif
#define CONCAT(a,b) CONCAT1(a,b)
#define CONCAT1(a,b) a##b
#ifndef STRUCTURE
# define STRUCTURE ENTNAME
#endif
struct parser_data
{
#ifdef ENTDATA
struct ENTDATA entdata;
# define ENTDATA_DECL(data) struct ENTDATA *const entdata = &data->entdata;
#else
# define ENTDATA_DECL(data)
#endif
char linebuffer[0];
};
#ifdef ENTDATA
/* The function can't be exported, because the entdata structure
is defined only in files-foo.c. */
# define parser_stclass static
# define nss_files_parse_hidden_def(name)
#else
/* Export the line parser function so it can be used in nss_db. */
# define parser_stclass /* Global */
# define parse_line CONCAT(_nss_files_parse_,ENTNAME)
# if IS_IN (libc)
/* We are defining one of the functions that actually lives in libc
because it is used to implement fget*ent and suchlike. */
# define nss_files_parse_hidden_def(name) libc_hidden_def (name)
# else
# define nss_files_parse_hidden_def(name) libnss_files_hidden_def (name)
# endif
#endif
#ifdef EXTERN_PARSER
/* The parser is defined in a different module. */
extern int parse_line (char *line, void *result,
struct parser_data *data, size_t datalen, int *errnop
EXTRA_ARGS_DECL);
# define LINE_PARSER(EOLSET, BODY) /* Do nothing */
#else
/* Define a line parsing function. */
# define LINE_PARSER(EOLSET, BODY) \
parser_stclass int \
parse_line (char *line, void *generic_result, \
struct parser_data *data, size_t datalen, int *errnop \
EXTRA_ARGS_DECL) \
{ \
struct STRUCTURE *result = generic_result; \
ENTDATA_DECL (data) \
BUFFER_PREPARE \
char *p = strpbrk (line, EOLSET "\n"); \
if (p != NULL) \
*p = '\0'; \
BODY; \
TRAILING_LIST_PARSER; \
return 1; \
} \
nss_files_parse_hidden_def (parse_line)
# define STRING_FIELD(variable, terminator_p, swallow) \
{ \
variable = line; \
while (*line != '\0' && !terminator_p (*line)) \
++line; \
if (*line != '\0') \
{ \
*line = '\0'; \
do \
++line; \
while (swallow && terminator_p (*line)); \
} \
}
# define STRING_LIST(variable, terminator_c) \
{ \
char **list = parse_list (&line, buf_start, buf_end, terminator_c, \
errnop); \
if (list) \
variable = list; \
else \
return -1; /* -1 indicates we ran out of space. */ \
\
/* Determine the new end of the buffer. */ \
while (*list != NULL) \
++list; \
buf_start = (char *) (list + 1); \
}
/* Helper function. */
static inline uint32_t
__attribute__ ((always_inline))
strtou32 (const char *nptr, char **endptr, int base)
{
unsigned long int val = strtoul (nptr, endptr, base);
/* Match the 32-bit behavior on 64-bit platforms. */
if (sizeof (long int) > 4 && val > 0xffffffff)
val = 0xffffffff;
return val;
}
# define INT_FIELD(variable, terminator_p, swallow, base, convert) \
{ \
char *endp; \
variable = convert (strtou32 (line, &endp, base)); \
if (endp == line) \
return 0; \
else if (terminator_p (*endp)) \
do \
++endp; \
while (swallow && terminator_p (*endp)); \
else if (*endp != '\0') \
return 0; \
line = endp; \
}
# define INT_FIELD_MAYBE_NULL(variable, terminator_p, swallow, base, convert, default) \
{ \
char *endp; \
if (*line == '\0') \
/* We expect some more input, so don't allow the string to end here. */ \
return 0; \
variable = convert (strtou32 (line, &endp, base)); \
if (endp == line) \
variable = default; \
if (terminator_p (*endp)) \
do \
++endp; \
while (swallow && terminator_p (*endp)); \
else if (*endp != '\0') \
return 0; \
line = endp; \
}
# define ISCOLON(c) ((c) == ':')
# ifndef TRAILING_LIST_MEMBER
# define BUFFER_PREPARE /* Nothing to do. */
# define TRAILING_LIST_PARSER /* Nothing to do. */
# else
# define BUFFER_PREPARE \
char *buf_start = NULL; \
char *buf_end = (char *) data + datalen; \
if (line >= data->linebuffer && line < buf_end) \
/* Find the end of the line buffer, we will use the space in \
DATA after it for storing the vector of pointers. */ \
buf_start = strchr (line, '\0') + 1; \
else \
/* LINE does not point within DATA->linebuffer, so that space is \
not being used for scratch space right now. We can use all of \
it for the pointer vector storage. */ \
buf_start = data->linebuffer; \
# define TRAILING_LIST_PARSER \
{ \
if (buf_start == NULL) \
{ \
if (line >= data->linebuffer && line < buf_end) \
/* Find the end of the line buffer, we will use the space in \
DATA after it for storing the vector of pointers. */ \
buf_start = strchr (line, '\0') + 1; \
else \
/* LINE does not point within DATA->linebuffer, so that space is \
not being used for scratch space right now. We can use all of \
it for the pointer vector storage. */ \
buf_start = data->linebuffer; \
} \
\
char **list = parse_list (&line, buf_start, buf_end, '\0', errnop); \
if (list) \
result->TRAILING_LIST_MEMBER = list; \
else \
return -1; /* -1 indicates we ran out of space. */ \
}
static inline char **
__attribute ((always_inline))
parse_list (char **linep, char *eol, char *buf_end, int terminator_c,
int *errnop)
{
char *line = *linep;
char **list, **p;
/* Adjust the pointer so it is aligned for storing pointers. */
eol += __alignof__ (char *) - 1;
eol -= (eol - (char *) 0) % __alignof__ (char *);
/* We will start the storage here for the vector of pointers. */
list = (char **) eol;
p = list;
while (1)
{
if ((char *) (p + 2) > buf_end)
{
/* We cannot fit another pointer in the buffer. */
*errnop = ERANGE;
return NULL;
}
if (*line == '\0')
break;
if (*line == terminator_c)
{
++line;
break;
}
/* Skip leading white space. This might not be portable but useful. */
while (isspace (*line))
++line;
char *elt = line;
while (1)
{
if (*line == '\0' || *line == terminator_c
|| TRAILING_LIST_SEPARATOR_P (*line))
{
/* End of the next entry. */
if (line > elt)
/* We really found some data. */
*p++ = elt;
/* Terminate string if necessary. */
if (*line != '\0')
{
char endc = *line;
*line++ = '\0';
if (endc == terminator_c)
goto out;
}
break;
}
++line;
}
}
out:
*p = NULL;
*linep = line;
return list;
}
# endif /* TRAILING_LIST_MEMBER */
#endif /* EXTERN_PARSER */
#define LOOKUP_NAME(nameelt, aliaselt) \
{ \
char **ap; \
if (! strcmp (name, result->nameelt)) \
break; \
for (ap = result->aliaselt; *ap; ++ap) \
if (! strcmp (name, *ap)) \
break; \
if (*ap) \
break; \
}
#define LOOKUP_NAME_CASE(nameelt, aliaselt) \
{ \
char **ap; \
if (! __strcasecmp (name, result->nameelt)) \
break; \
for (ap = result->aliaselt; *ap; ++ap) \
if (! __strcasecmp (name, *ap)) \
break; \
if (*ap) \
break; \
}
/* This is defined by db-*.c to include "../nss_db/db-XXX.c" instead. */
#ifndef GENERIC
# define GENERIC "files-XXX.c"
#endif
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