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nuttx/libs/libc/grp/lib_find_grpfile.c

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/****************************************************************************
* libs/libc/grp/lib_find_grpfile.c
*
* Copyright (C) 2019 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <grp.h>
#include <assert.h>
#include "grp/lib_grp.h"
/****************************************************************************
* Private Types
****************************************************************************/
typedef CODE int (grp_foreach_match_t)(FAR const struct group *entry,
uintptr_t arg);
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: grp_match_name
*
* Description:
* Called for each record in the group file. Returns "1" if the record
* matches the group name (passed as arg)
*
* Input Parameters:
* entry - The parsed group file record
* arg - A pointer to the group name to match
*
* Returned Value:
* < 0 : An error has occurred.
* = 0 : No entry name does not match.
* = 1 : The entry name matches
*
****************************************************************************/
static int grp_match_name(FAR const struct group *entry, uintptr_t arg)
{
FAR const char *gname = (FAR const char *)arg;
return strcmp(entry->gr_name, gname) == 0 ? 1 : 0;
}
/****************************************************************************
* Name: grp_match_gid
*
* Description:
* Called for each record in the group file. Returns "1" if the record
* matches the group ID (passed as arg)
*
* Input Parameters:
* entry - The parsed group file record
* arg - The group ID to match
*
* Returned Value:
* < 0 : An error has occurred.
* = 0 : No entry name does not match.
* = 1 : The entry name matches
*
****************************************************************************/
static int grp_match_gid(FAR const struct group *entry, uintptr_t arg)
{
int match_gid = (int)arg;
return match_gid == entry->gr_gid ? 1 : 0;
}
/****************************************************************************
* Name: grp_foreach
*
* Description:
* Visit each record in group file.
*
* Input Parameters:
* match - The match function to call on each record
* arg - Argument passed to the match function
* entry - Location to return the parsed group file entry
* buffer - I/O buffer used to access the group file
* buflen - The size of the I/O buffer in bytes
*
* Returned Value:
* < 0 : An error has occurred.
* = 0 : No entry with this name was found.
* = 1 : The entry with this name was found.
*
****************************************************************************/
static int grp_foreach(grp_foreach_match_t match, uintptr_t arg,
FAR struct group *entry, FAR char *buffer,
size_t buflen)
{
FAR FILE *stream;
FAR char *ptr;
FAR char *line;
FAR char *save;
size_t linelen;
unsigned int nmembers;
int ret;
stream = fopen(CONFIG_LIBC_GROUP_FILEPATH, "r");
if (stream == NULL)
{
int errcode = errno;
DEBUGASSERT(errno > 0);
return -errcode;
}
/* Read the password file line by line until the record with the matching
* username is found, or until the end of the file is reached.
*
* The format of the password file is:
*
* user:x:uid:gid:home
*
* Where:
* user: User name
* x: Encrypted password
* uid: User ID
* gid: Group ID
* home: Login directory
*/
DEBUGASSERT(buflen > MEMBER_SIZE); /* Buffer must also be aligned */
line = buffer + MEMBER_SIZE;
linelen = buflen - MEMBER_SIZE;
while (fgets(line, linelen, stream) != NULL)
{
ptr = line;
entry->gr_name = ptr;
/* Skip to the end of the name and properly terminate it. The name
* must be terminated with the field delimiter ':'.
*/
for (; *ptr != '\n' && *ptr != '\0' && *ptr != ':'; ptr++)
{
}
if (*ptr == '\n' || *ptr == '\0')
{
/* Bad line format? */
continue;
}
*ptr++ = '\0';
entry->gr_passwd = ptr;
/* Skip to the end of the password and properly terminate it. The
* password must be terminated with the field delimiter ':'.
*/
for (; *ptr != '\n' && *ptr != '\0' && *ptr != ':'; ptr++)
{
}
if (*ptr == '\n' || *ptr == '\0')
{
/* Bad line format? */
continue;
}
*ptr++ = '\0';
save = ptr;
/* Skip to the end of the group ID and properly terminate it. The
* group ID must be terminated with the field delimiter ':'.
*/
for (; *ptr != '\n' && *ptr != '\0' && *ptr != ':'; ptr++)
{
}
if (*ptr == '\n' || *ptr == '\0')
{
/* Bad line format? */
continue;
}
*ptr++ = '\0';
entry->gr_gid = (gid_t)atoi(save);
/* This is followed by a variable number of user names. The ':'
* delimited will be followed by '\n' or '\0' if there are no users
* in the group
*/
nmembers = 0;
entry->gr_mem = (FAR char **)buffer;
if (*ptr != '\n' && *ptr != '\0')
{
for (; ; )
{
/* Add the next user name */
entry->gr_mem[nmembers] = ptr;
nmembers++;
if (nmembers >= CONFIG_LIBC_GROUP_NUSERS)
{
break;
}
/* Skip to the end of the user name and properly terminate it.
* The user name must be terminated with either (1) ','
* meaning that another user name is present, or (2) '\n' or
* '\0' meaning that we have reached the end of the line and
* there are no further user names.
*/
for (; *ptr != '\n' && *ptr != '\0' && *ptr != ','; ptr++)
{
}
if (*ptr == '\n' || *ptr == '\0')
{
*ptr = '\0';
break;
}
*ptr++ = '\0';
}
}
/* The list terminates with a NULL pointer */
entry->gr_mem[nmembers] = NULL;
/* Check for a match */
ret = match(entry, arg);
if (ret != 0)
{
/* We either have the match or an error occurred. */
fclose(stream);
return ret;
}
}
fclose(stream);
return 0;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: grp_findby_name
*
* Description:
* Find group file entry using the group name.
*
* Input Parameters:
* gname - The group name
* entry - Location to return the parsed group file entry
* buffer - I/O buffer used to access the group file
* buflen - The size of the I/O buffer in bytes
*
* Returned Value:
* < 0 : An error has occurred.
* = 0 : No entry with this name was found.
* = 1 : The entry with this name was found.
*
****************************************************************************/
int grp_findby_name(FAR const char *gname, FAR struct group *entry,
FAR char *buffer, size_t buflen)
{
return grp_foreach(grp_match_name, (uintptr_t)gname, entry, buffer, buflen);
}
/****************************************************************************
* Name: grp_findby_gid
*
* Description:
* Find group file entry using the group ID.
*
* Input Parameters:
* gid - The group ID
* entry - Location to return the parsed group file entry
* buffer - I/O buffer used to access the group file
* buflen - The size of the I/O buffer in bytes
*
* Returned Value:
* < 0 : An error has occurred.
* = 0 : No entry with this name was found.
* = 1 : The entry with this name was found.
*
****************************************************************************/
int grp_findby_gid(gid_t gid, FAR struct group *entry, FAR char *buffer,
size_t buflen)
{
/* Verify that the GID is in the valid range of 0 through INT16_MAX.
* OpenGroup.org does not specify a GID_MAX or GID_MIN. Instead we use a
* priori knowledge that gid_t is type int16_t.
*/
if ((uint16_t)gid > INT16_MAX)
{
return -EINVAL;
}
return grp_foreach(grp_match_gid, (uintptr_t)gid, entry, buffer, buflen);
}
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