diff options
Diffstat (limited to 'libstore/encode.c')
| -rw-r--r-- | libstore/encode.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/libstore/encode.c b/libstore/encode.c new file mode 100644 index 00000000..48c5d26a --- /dev/null +++ b/libstore/encode.c @@ -0,0 +1,167 @@ +/* Store wire encoding + + Copyright (C) 1996, 1997, 1999 Free Software Foundation, Inc. + Written by Miles Bader <miles@gnu.ai.mit.edu> + This file is part of the GNU Hurd. + + The GNU Hurd 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, or (at + your option) any later version. + + The GNU Hurd 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, USA. */ + +#include <string.h> +#include <sys/mman.h> + +#include "store.h" + +/* Standard encoding used for most leaf store types. */ + +error_t +store_std_leaf_allocate_encoding (const struct store *store, + struct store_enc *enc) +{ + enc->num_ports++; + enc->num_ints += 6; + enc->num_offsets += store->num_runs * 2; + if (store->name) + enc->data_len += strlen (store->name) + 1; + enc->data_len += store->misc_len; + return 0; +} + +error_t +store_std_leaf_encode (const struct store *store, struct store_enc *enc) +{ + int i; + size_t name_len = (store->name ? strlen (store->name) + 1 : 0); + + enc->ports[enc->cur_port++] = store->port; + + enc->ints[enc->cur_int++] = store->class->id; + enc->ints[enc->cur_int++] = store->flags; + enc->ints[enc->cur_int++] = store->block_size; + enc->ints[enc->cur_int++] = store->num_runs; + enc->ints[enc->cur_int++] = name_len; + enc->ints[enc->cur_int++] = store->misc_len; + + for (i = 0; i < store->num_runs; i++) + { + enc->offsets[enc->cur_offset++] = store->runs[i].start; + enc->offsets[enc->cur_offset++] = store->runs[i].length; + } + + if (store->name) + { + bcopy (store->name, enc->data + enc->cur_data, name_len); + enc->cur_data += name_len; + } + if (store->misc_len) + { + bcopy (store->misc, enc->data + enc->cur_data, store->misc_len); + enc->cur_data += store->misc_len; + } + + return 0; +} + +/* Encode STORE into ENC, which should have been prepared with + store_enc_init, or return an error. The contents of ENC may then be + return as the value of file_get_storage_info; if for some reason this + can't be done, store_enc_dealloc may be used to deallocate the mmemory + used by the unsent vectors. */ +error_t +store_encode (const struct store *store, struct store_enc *enc) +{ + void *buf; + error_t err; + const struct store_class *class = store->class; + /* We zero each vector length for the allocate_encoding method to work, so + save the old values. */ + mach_msg_type_number_t init_num_ports = enc->num_ports; + mach_msg_type_number_t init_num_ints = enc->num_ints; + mach_msg_type_number_t init_num_offsets = enc->num_offsets; + mach_msg_type_number_t init_data_len = enc->data_len; + + if (!class->allocate_encoding || !class->encode) + return EOPNOTSUPP; + + enc->num_ports = 0; + enc->num_ints = 0; + enc->num_offsets = 0; + enc->data_len = 0; + err = (*class->allocate_encoding) (store, enc); + if (err) + return err; + + errno = 0; + if (enc->num_ports > init_num_ports) + { + buf = mmap (0, enc->num_ports * sizeof *enc->ports, + PROT_READ|PROT_WRITE, MAP_ANON, 0, 0); + if (buf != (void *) -1) + enc->ports = buf; + } + if (!errno && enc->num_ints > init_num_ints) + { + buf = mmap (0, enc->num_ints * sizeof *enc->ints, + PROT_READ|PROT_WRITE, MAP_ANON, 0, 0); + if (buf != (void *) -1) + enc->ints = buf; + } + if (!errno && enc->num_offsets > init_num_offsets) + { + buf = mmap (0, enc->num_offsets * sizeof *enc->offsets, + PROT_READ|PROT_WRITE, MAP_ANON, 0, 0); + if (buf != (void *) -1) + enc->offsets = buf; + + } + if (!errno && enc->data_len > init_data_len) + { + buf = mmap (0, enc->data_len, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0); + if (buf != (void *) -1) + enc->data = buf; + } + err = errno; + if (! err) + err = (*class->encode) (store, enc); + + enc->cur_port = enc->cur_int = enc->cur_offset = enc->cur_data = 0; + + if (err) + store_enc_dealloc (enc); + + return err; +} + +/* Encode STORE into the given return variables, suitably for returning from a + file_get_storage_info rpc. */ +error_t +store_return (const struct store *store, + mach_port_t **ports, mach_msg_type_number_t *num_ports, + int **ints, mach_msg_type_number_t *num_ints, + off_t **offsets, mach_msg_type_number_t *num_offsets, + char **data, mach_msg_type_number_t *data_len) +{ + error_t err; + struct store_enc enc; + + store_enc_init (&enc, *ports, *num_ports, *ints, *num_ints, + *offsets, *num_offsets, *data, *data_len); + err = store_encode (store, &enc); + if (err) + store_enc_dealloc (&enc); + else + store_enc_return (&enc, ports, num_ports, ints, num_ints, + offsets, num_offsets, data, data_len); + return err; +} |