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libc: Implement pathconf and fpathconf

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specified here:
https://pubs.opengroup.org/onlinepubs/009695399/functions/fpathconf.html
note: only _PC_PATH_MAX is handled now

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Idd323dc10e8f31f10dd1fc64f467227808c11dbd
This commit is contained in:
Xiang Xiao 2020-06-22 14:34:59 +08:00 committed by Abdelatif Guettouche
parent 1e166f7ecb
commit d24bd782a9
3 changed files with 160 additions and 2 deletions
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28
include/unistd.h
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@ -103,7 +103,31 @@
#undef _POSIX_ASYNC_IO
#undef _POSIX_PRIO_IO
/* Constants used with POSIX sysconf(). sysconf() will return -2 and set
/* Constants used with POSIX pathconf(). pathconf() will return -1 and set
* errno to ENOSYS for most of these.
*/
#define _PC_2_SYMLINKS 0x0001
#define _PC_ALLOC_SIZE_MIN 0x0002
#define _PC_ASYNC_IO 0x0003
#define _PC_CHOWN_RESTRICTED 0x0004
#define _PC_FILESIZEBITS 0x0005
#define _PC_LINK_MAX 0x0006
#define _PC_MAX_CANON 0x0007
#define _PC_MAX_INPUT 0x0008
#define _PC_NAME_MAX 0x0009
#define _PC_NO_TRUNC 0x000a
#define _PC_PATH_MAX 0x000b
#define _PC_PIPE_BUF 0x000c
#define _PC_PRIO_IO 0x000d
#define _PC_REC_INCR_XFER_SIZE 0x000e
#define _PC_REC_MIN_XFER_SIZE 0x000f
#define _PC_REC_XFER_ALIGN 0x0010
#define _PC_SYMLINK_MAX 0x0011
#define _PC_SYNC_IO 0x0012
#define _PC_VDISABLE 0x0013
/* Constants used with POSIX sysconf(). sysconf() will return -1 and set
* errno to ENOSYS for most of these.
*/
@ -365,6 +389,8 @@ int sethostname(FAR const char *name, size_t size);
/* Get configurable system variables */
long sysconf(int name);
long fpathconf(int fildes, int name);
long pathconf(FAR const char *path, int name);
/* User and group identity management */

2
libs/libc/unistd/Make.defs
View File

@ -35,7 +35,7 @@
# Add the unistd C files to the build
CSRCS += lib_access.c lib_daemon.c lib_swab.c lib_sysconf.c
CSRCS += lib_access.c lib_daemon.c lib_swab.c lib_pathconf.c lib_sysconf.c
CSRCS += lib_getopt.c lib_getoptargp.c lib_getoptindp.c lib_getoptoptp.c
CSRCS += lib_alarm.c lib_sleep.c lib_usleep.c
CSRCS += lib_seteuid.c lib_setegid.c lib_geteuid.c lib_getegid.c

132
libs/libc/unistd/lib_pathconf.c Normal file
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@ -0,0 +1,132 @@
/****************************************************************************
* libs/libc/unistd/lib_pathconf.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: fpathconf/pathconf
*
* Description:
* The fpathconf() and pathconf() functions shall determine the current
* value of a configurable limit or option (variable) that is associated
* with a file or directory.
*
* For pathconf(), the path argument points to the pathname of a file or
* directory.
*
* For fpathconf(), the fildes argument is an open file descriptor.
*
* The name argument represents the variable to be queried relative to that
* file or directory. Implementations shall support all of the variables
* listed in the following table and may support others. The variables in
* the following table come from <limits.h> or <unistd.h> and the symbolic
* constants, defined in <unistd.h>, are the corresponding values used for
* name.
*
* Variable Value of Name
*
* {FILESIZEBITS} _PC_FILESIZEBITS
* {LINK_MAX} _PC_LINK_MAX
* {MAX_CANON} _PC_MAX_CANON
* {MAX_INPUT} _PC_MAX_INPUT
* {NAME_MAX} _PC_NAME_MAX
* {PATH_MAX} _PC_PATH_MAX
* {PIPE_BUF} _PC_PIPE_BUF
* {POSIX2_SYMLINKS} _PC_2_SYMLINKS
* {POSIX_ALLOC_SIZE_MIN} _PC_ALLOC_SIZE_MIN
* {POSIX_REC_INCR_XFER_SIZE} _PC_REC_INCR_XFER_SIZE
* {POSIX_REC_MAX_XFER_SIZE} _PC_REC_MAX_XFER_SIZE
* {POSIX_REC_MIN_XFER_SIZE} _PC_REC_MIN_XFER_SIZE
* {POSIX_REC_XFER_ALIGN} _PC_REC_XFER_ALIGN
* {SYMLINK_MAX} _PC_SYMLINK_MAX
* _POSIX_CHOWN_RESTRICTED _PC_CHOWN_RESTRICTED
* _POSIX_NO_TRUNC _PC_NO_TRUNC
* _POSIX_VDISABLE _PC_VDISABLE
* _POSIX_ASYNC_IO _PC_ASYNC_IO
* _POSIX_PRIO_IO _PC_PRIO_IO
* _POSIX_SYNC_IO _PC_SYNC_IO
*
* Returned Value:
* If name is an invalid value, both pathconf() and fpathconf() shall
* return -1 and set errno to indicate the error.
*
* If the variable corresponding to name has no limit for the path or file
* descriptor, both pathconf() and fpathconf() shall return -1 without
* changing errno. If the implementation needs to use path to determine the
* value of name and the implementation does not support the association of
* name with the file specified by path, or if the process did not have
* appropriate privileges to query the file specified by path, or path does
* not exist, pathconf() shall return -1 and set errno to indicate the
* error.
*
* If the implementation needs to use fildes to determine the value of name
* and the implementation does not support the association of name with the
* file specified by fildes, or if fildes is an invalid file descriptor,
* fpathconf() shall return -1 and set errno to indicate the error.
*
* Otherwise, pathconf() or fpathconf() shall return the current variable
* value for the file or directory without changing errno. The value
* returned shall not be more restrictive than the corresponding value
* available to the application when it was compiled with the
* implementation's <limits.h> or <unistd.h>.
*
* If the variable corresponding to name is dependent on an unsupported
* option, the results are unspecified.
*
****************************************************************************/
long fpathconf(int fildes, int name)
{
/* NOTE: The initialize implementation of this interface is very sparse.
* It was originally created to support only the functionality of libcxx
* but can be extended to support as much of the standard POSIX as is
* necessary.
*/
switch (name)
{
case _PC_PATH_MAX:
return PATH_MAX;
default:
/* Assume valid but not implemented for the time being */
set_errno(ENOSYS);
return ERROR;
}
}
long pathconf(FAR const char *path, int name)
{
return fpathconf(-1, name);
}