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Diffstat (limited to 'trans/null.c')
| -rw-r--r-- | trans/null.c | 318 |
1 files changed, 318 insertions, 0 deletions
diff --git a/trans/null.c b/trans/null.c new file mode 100644 index 00000000..ecec5c94 --- /dev/null +++ b/trans/null.c @@ -0,0 +1,318 @@ +/* A translator for providing endless empty space and immediate eof. + + Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc. + + Written by Miles Bader <miles@gnu.ai.mit.edu> + + 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, 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#include <hurd.h> +#include <hurd/ports.h> +#include <hurd/trivfs.h> +#include <hurd/fsys.h> +#include <version.h> + +#include <stdio.h> +#include <unistd.h> +#include <error.h> +#include <string.h> +#include <fcntl.h> +#include <limits.h> +#include <argp.h> + +const char *argp_program_version = STANDARD_HURD_VERSION (null); + +/* Error code to return for write attempts. + If zero, they succeed in writing to the bitbucket. */ +static error_t write_error_code; + +static const struct argp_option options[] = +{ + {"full", 'f', 0, 0, "Cause writes to fail as if to a full disk"}, + {0} +}; + +static error_t +parse_opt (int opt, char *arg, struct argp_state *state) +{ + switch (opt) + { + case 'f': + write_error_code = ENOSPC; + return 0; + } + return ARGP_ERR_UNKNOWN; +} + +static const struct argp argp = +{ options, parse_opt, 0, "Endless sink and null source" }; + +int +main (int argc, char **argv) +{ + error_t err; + mach_port_t bootstrap; + struct trivfs_control *fsys; + + argp_parse (&argp, argc, argv, 0, 0, 0); + + task_get_bootstrap_port (mach_task_self (), &bootstrap); + if (bootstrap == MACH_PORT_NULL) + error(1, 0, "Must be started as a translator"); + + /* Reply to our parent */ + err = trivfs_startup (bootstrap, 0, 0, 0, 0, 0, &fsys); + mach_port_deallocate (mach_task_self (), bootstrap); + if (err) + error(3, err, "Contacting parent"); + + /* Launch. */ + ports_manage_port_operations_multithread (fsys->pi.bucket, trivfs_demuxer, + 2 * 60 * 1000, 0, 0); + + return 0; +} + +/* Trivfs hooks */ + +int trivfs_fstype = FSTYPE_DEV; +int trivfs_fsid = 0; + +int trivfs_support_read = 1; +int trivfs_support_write = 1; +int trivfs_support_exec = 0; + +int trivfs_allow_open = O_READ | O_WRITE; + +void +trivfs_modify_stat (struct trivfs_protid *cred, struct stat *st) +{ + st->st_blksize = vm_page_size * 256; /* Make transfers LARRRRRGE */ + + st->st_size = 0; + st->st_blocks = 0; + + st->st_mode &= ~S_IFMT; + st->st_mode |= S_IFCHR; +} + +error_t +trivfs_goaway (struct trivfs_control *fsys, int flags) +{ + exit (0); +} + +/* Return objects mapping the data underlying this memory object. If + the object can be read then memobjrd will be provided; if the + object can be written then memobjwr will be provided. For objects + where read data and write data are the same, these objects will be + equal, otherwise they will be disjoint. Servers are permitted to + implement io_map but not io_map_cntl. Some objects do not provide + mapping; they will set none of the ports and return an error. Such + objects can still be accessed by io_read and io_write. */ +kern_return_t +trivfs_S_io_map(struct trivfs_protid *cred, + memory_object_t *rdobj, + mach_msg_type_name_t *rdtype, + memory_object_t *wrobj, + mach_msg_type_name_t *wrtype) +{ + return EINVAL; /* XXX should work! */ +} + +/* Read data from an IO object. If offset if -1, read from the object + maintained file pointer. If the object is not seekable, offset is + ignored. The amount desired to be read is in AMT. */ +kern_return_t +trivfs_S_io_read(struct trivfs_protid *cred, + mach_port_t reply, mach_msg_type_name_t replytype, + vm_address_t *data, + mach_msg_type_number_t *datalen, + off_t offs, + mach_msg_type_number_t amt) +{ + if (!cred) + return EOPNOTSUPP; + else if (!(cred->po->openmodes & O_READ)) + return EBADF; + else + { + *datalen = 0; + return 0; + } +} + +/* Tell how much data can be read from the object without blocking for + a "long time" (this should be the same meaning of "long time" used + by the nonblocking flag. */ +kern_return_t +trivfs_S_io_readable (struct trivfs_protid *cred, + mach_port_t reply, mach_msg_type_name_t replytype, + mach_msg_type_number_t *amount) +{ + if (!cred) + return EOPNOTSUPP; + else if (!(cred->po->openmodes & O_READ)) + return EINVAL; + else + *amount = 0; + return 0; +} + +/* Change current read/write offset */ +kern_return_t +trivfs_S_io_seek (struct trivfs_protid *cred, + mach_port_t reply, mach_msg_type_name_t replytype, + off_t offset, int whence, off_t *new_offset) +{ + if (!cred) + return EOPNOTSUPP; + *new_offset = 0; + return 0; +} + +/* SELECT_TYPE is the bitwise OR of SELECT_READ, SELECT_WRITE, and SELECT_URG. + Block until one of the indicated types of i/o can be done "quickly", and + return the types that are then available. ID_TAG is returned as passed; it + is just for the convenience of the user in matching up reply messages with + specific requests sent. */ +kern_return_t +trivfs_S_io_select (struct trivfs_protid *cred, + mach_port_t reply, mach_msg_type_name_t replytype, + int *type, int *tag) +{ + if (!cred) + return EOPNOTSUPP; + else if (((*type & SELECT_READ) && !(cred->po->openmodes & O_READ)) + || ((*type & SELECT_WRITE) && !(cred->po->openmodes & O_WRITE))) + return EBADF; + else + *type &= ~SELECT_URG; + return 0; +} + +/* Write data to an IO object. If offset is -1, write at the object + maintained file pointer. If the object is not seekable, offset is + ignored. The amount successfully written is returned in amount. A + given user should not have more than one outstanding io_write on an + object at a time; servers implement congestion control by delaying + responses to io_write. Servers may drop data (returning ENOBUFS) + if they recevie more than one write when not prepared for it. */ +kern_return_t +trivfs_S_io_write (struct trivfs_protid *cred, + mach_port_t reply, mach_msg_type_name_t replytype, + vm_address_t data, mach_msg_type_number_t datalen, + off_t offs, mach_msg_type_number_t *amt) +{ + if (!cred) + return EOPNOTSUPP; + else if (!(cred->po->openmodes & O_WRITE)) + return EBADF; + *amt = datalen; + return write_error_code; +} + +/* Truncate file. */ +kern_return_t +trivfs_S_file_set_size (struct trivfs_protid *cred, off_t size) +{ + return 0; +} + +/* These four routines modify the O_APPEND, O_ASYNC, O_FSYNC, and + O_NONBLOCK bits for the IO object. In addition, io_get_openmodes + will tell you which of O_READ, O_WRITE, and O_EXEC the object can + be used for. The O_ASYNC bit affects icky async I/O; good async + I/O is done through io_async which is orthogonal to these calls. */ + +kern_return_t +trivfs_S_io_get_openmodes (struct trivfs_protid *cred, + mach_port_t reply, mach_msg_type_name_t replytype, + int *bits) +{ + if (!cred) + return EOPNOTSUPP; + else + { + *bits = cred->po->openmodes; + return 0; + } +} + +error_t +trivfs_S_io_set_all_openmodes(struct trivfs_protid *cred, + mach_port_t reply, + mach_msg_type_name_t replytype, + int mode) +{ + if (!cred) + return EOPNOTSUPP; + else + return 0; +} + +kern_return_t +trivfs_S_io_set_some_openmodes (struct trivfs_protid *cred, + mach_port_t reply, + mach_msg_type_name_t replytype, + int bits) +{ + if (!cred) + return EOPNOTSUPP; + else + return 0; +} + +kern_return_t +trivfs_S_io_clear_some_openmodes (struct trivfs_protid *cred, + mach_port_t reply, + mach_msg_type_name_t replytype, + int bits) +{ + if (!cred) + return EOPNOTSUPP; + else + return 0; +} + +/* Get/set the owner of the IO object. For terminals, this affects + controlling terminal behavior (see term_become_ctty). For all + objects this affects old-style async IO. Negative values represent + pgrps. This has nothing to do with the owner of a file (as + returned by io_stat, and as used for various permission checks by + filesystems). An owner of 0 indicates that there is no owner. */ + +kern_return_t +trivfs_S_io_get_owner (struct trivfs_protid *cred, + mach_port_t reply, + mach_msg_type_name_t replytype, + pid_t *owner) +{ + if (!cred) + return EOPNOTSUPP; + *owner = 0; + return 0; +} + +kern_return_t +trivfs_S_io_mod_owner (struct trivfs_protid *cred, + mach_port_t reply, mach_msg_type_name_t replytype, + pid_t owner) +{ + if (!cred) + return EOPNOTSUPP; + else + return EINVAL; +} |