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Diffstat (limited to 'netfs-sample/lib.c')
| -rw-r--r-- | netfs-sample/lib.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/netfs-sample/lib.c b/netfs-sample/lib.c new file mode 100644 index 00000000..aa0ff0be --- /dev/null +++ b/netfs-sample/lib.c @@ -0,0 +1,193 @@ +/*----------------------------------------------------------------------------*/ +/*lib.h*/ +/*----------------------------------------------------------------------------*/ +/*Basic routines for filesystem manipulations*/ +/*----------------------------------------------------------------------------*/ +/*Based on the code of unionfs translator.*/ +/*----------------------------------------------------------------------------*/ +/*Copyright (C) 2001, 2002, 2005 Free Software Foundation, Inc. + Written by Sergiu Ivanov <unlimitedscolobb@gmail.com>. + + This program is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2 of the + License, or * (at your option) any later version. + + This program 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 + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 + USA.*/ +/*----------------------------------------------------------------------------*/ + +/*----------------------------------------------------------------------------*/ +#define _GNU_SOURCE 1 +/*----------------------------------------------------------------------------*/ +#include <sys/mman.h> +/*----------------------------------------------------------------------------*/ +#include "lib.h" +#include "debug.h" +/*----------------------------------------------------------------------------*/ + +/*----------------------------------------------------------------------------*/ +/*--------Functions-----------------------------------------------------------*/ +/*Fetches directory entries for `dir`*/ +error_t +dir_entries_get + ( + file_t dir, + char ** dirent_data, /*the list of directory entries as returned + by dir_readdir*/ + size_t * dirent_data_size, /*the size of `dirent_data`*/ + struct dirent *** dirent_list /*the array of pointers to beginnings of + dirents in dirent_data*/ + ) + { + error_t err = 0; + + /*The data (array of dirents(?)) returned by dir_readdir*/ + char * data; + + /*The size of `data`*/ + size_t data_size; + + /*The number of entries in `data`*/ + int entries_num; + + /*Try to read the contents of the specified directory*/ + err = dir_readdir(dir, &data, &data_size, 0, -1, 0, &entries_num); + if(err) + return err; + + /*Create a new list of dirents*/ + struct dirent ** list; + + /*Allocate the memory for the list of dirents and for the + finalizing element*/ + list = malloc(sizeof(struct dirent *) * (entries_num + 1)); + + /*If memory allocation has failed*/ + if(!list) + { + /*free the result of dir_readdir*/ + munmap(data, data_size); + + /*return the corresponding error*/ + return ENOMEM; + } + + /*The current directory entry*/ + struct dirent * dp; + + int i; + + /*Go through every element of the list of dirents*/ + for + ( + i = 0, dp = (struct dirent *)data; + i < entries_num; + ++i, dp = (struct dirent *)((char *)dp + dp->d_reclen)) + /*copy the current value into the list*/ + *(list + i) = dp; + + /*Nullify the last element of the list*/ + *(list + i) = NULL; + + /*Copy the required values in the parameters*/ + *dirent_data = data; + *dirent_data_size = data_size; + *dirent_list = list; + + /*Return success*/ + return err; + }/*dir_entries_get*/ +/*----------------------------------------------------------------------------*/ +/*Lookup `name` under `dir` (or cwd, if `dir` is invalid)*/ +error_t +file_lookup + ( + file_t dir, + char * name, + int flags0, /*try to open with these flags first*/ + int flags1, /*try to open with these flags, if `flags0` fail*/ + int mode, /*if the file is to be created, create it with this mode*/ + file_t * port, /*store the port to the looked up file here*/ + io_statbuf_t * stat /*store the stat information here*/ + ) + { + error_t err = 0; + + /*The port to the looked up file*/ + file_t p; + + /*The stat information about the looked up file*/ + io_statbuf_t s; + + /*Performs a lookup under 'dir' or in cwd, if `dir` is invalid*/ + file_t + do_file_lookup + ( + file_t dir, + char * name, /*lookup this file*/ + int flags, /*lookup the file with these flags*/ + int mode /*if a new file is to be created, create it with this mode*/ + ) + { + /*The result of lookup*/ + file_t p; + + /*If `dir` is a valid port*/ + if(dir != MACH_PORT_NULL) + /*try to lookup `name` under `dir`*/ + p = file_name_lookup_under(dir, name, flags, mode); + else + /*lookup `name` under current cwd*/ + p = file_name_lookup(name, flags, mode); + + /*Return the result of the lookup*/ + return p; + }/*do_file_lookup*/ + + /*Lookup `name` under the suggested `dir`*/ + p = do_file_lookup(dir, name, flags0, mode); + + /*If the lookup failed*/ + if(p == MACH_PORT_NULL) + /*try to lookup for `name` using alternative flags `flags1`*/ + p = do_file_lookup(dir, name, flags1, mode); + + /*If the port is valid*/ + if(p != MACH_PORT_NULL) + { + /*If stat information is required*/ + if(stat) + { + /*obtain stat information for `p`*/ + err = io_stat(p, &s); + if(err) + PORT_DEALLOC(p); + } + } + else + /*copy `errno` into `err`*/ + err = errno; + + /*If no errors have happened during lookup*/ + if(!err) + { + /*copy the resulting port into *`port`*/ + *port = p; + + /*fill in the receiver for stat information, if requried*/ + if(stat) + *stat = s; + } + + /*Return the result of performing operations*/ + return err; + }/*file_lookup*/ +/*----------------------------------------------------------------------------*/ |