diff options
| -rw-r--r-- | libdiskfs/filedev.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/libdiskfs/filedev.c b/libdiskfs/filedev.c new file mode 100644 index 00000000..5a3e752d --- /dev/null +++ b/libdiskfs/filedev.c @@ -0,0 +1,107 @@ +/* Get the mach device underlying a file + + Copyright (C) 1995 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 <errno.h> +#include <sys/fcntl.h> + +#include <device/device.h> + +#include "priv.h" + +typedef int run_elem_t; + +/* Returns the name and a send right for the mach device on which the file + NAME is stored, and returns it in DEV_NAME (which is malloced) and PORT. + Other values returned are START, the first valid offset, SIZE, the the + number of blocks after START, and BLOCK_SIZE, the units in which the + device is addressed. + + The device is opened for reading, and if the diskfs global variable + DISKFS_READONLY is false, writing. */ +error_t +diskfs_get_file_device (char *name, + char **dev_name, mach_port_t *port, + off_t *start, off_t *size, size_t *block_size) +{ + error_t err; + int class, flags; + char *misc = 0; + off_t *runs = 0; + mach_msg_type_number_t misc_len = 0, runs_len = 0; + string_t dev_name_buf; + file_t node = + file_name_lookup (name, diskfs_readonly ? O_RDONLY : O_RDWR, 0); + + if (node == MACH_PORT_NULL) + return errno; + + *port = MACH_PORT_NULL; + + err = file_get_storage_info (node, &class, &runs, &runs_len, block_size, + dev_name_buf, port, &misc, &misc_len, &flags); + if (err) + goto done; + + if (class != STORAGE_DEVICE) + { + err = ENODEV; + goto done; + } + + if (dev_name) + { + *dev_name = malloc (strlen (dev_name_buf) + 1); + if (*dev_name) + strcpy (*dev_name, dev_name_buf); + else + err = ENOMEM; + } + + if (start || size) + if (runs_len > 2) + /* We can't handle anything but a contiguous set of blocks. */ + err = ENODEV; /* XXX */ + else + { + if (start) + *start = runs[0]; + if (size) + *size = runs[1]; + } + + /* Note that we don't deallocate NODE, which should prevent the information + returned by file_get_storage_info from changing. */ + + done: + if (err) + { + mach_port_deallocate (mach_task_self (), node); + if (*port) + mach_port_deallocate (mach_task_self (), *port); + } + + if (misc_len > 0) + vm_deallocate (mach_task_self (), (vm_address_t)misc, misc_len); + if (runs_len > 0) + vm_deallocate (mach_task_self (), + (vm_address_t)runs, runs_len * sizeof (*runs)); + + return err; +} |