diff options
Diffstat (limited to 'libnetfs/io-read.c')
| -rw-r--r-- | libnetfs/io-read.c | 65 |
1 files changed, 52 insertions, 13 deletions
diff --git a/libnetfs/io-read.c b/libnetfs/io-read.c index 54914935..ff8fbcff 100644 --- a/libnetfs/io-read.c +++ b/libnetfs/io-read.c @@ -1,5 +1,5 @@ -/* - Copyright (C) 1995, 1996 Free Software Foundation, Inc. +/* + Copyright (C) 1995, 1996, 1997, 1999 Free Software Foundation, Inc. Written by Michael I. Bushnell, p/BSG. This file is part of the GNU Hurd. @@ -21,6 +21,7 @@ #include "netfs.h" #include "io_S.h" #include <fcntl.h> +#include <sys/mman.h> error_t netfs_S_io_read (struct protid *user, @@ -30,41 +31,79 @@ netfs_S_io_read (struct protid *user, mach_msg_type_number_t amount) { error_t err; + off_t start; + struct node *node; int alloced = 0; if (!user) return EOPNOTSUPP; + node = user->po->np; mutex_lock (&user->po->np->lock); if ((user->po->openstat & O_READ) == 0) { - mutex_unlock (&user->po->np->lock); + mutex_unlock (&node->lock); return EBADF; } if (amount > *datalen) { alloced = 1; - vm_allocate (mach_task_self (), (vm_address_t *) data, amount, 1); + *data = mmap (0, amount, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0); } *datalen = amount; - err = netfs_attempt_read (user->credential, user->po->np, - offset == -1 ? user->po->filepointer : offset, - datalen, *data); + start = (offset == -1 ? user->po->filepointer : offset); + + if (start < 0) + err = EINVAL; + else if (S_ISLNK (node->nn_stat.st_mode)) + /* Read from a symlink. */ + { + off_t size = node->nn_stat.st_size; + + if (start + amount > size) + amount = size - start; + if (amount > size) + amount = size; + + if (start >= size) + { + *datalen = 0; + err = 0; + } + else if (amount < size || start > 0) + { + char *whole_link = alloca (size); + err = netfs_attempt_readlink (user->user, node, whole_link); + if (! err) + { + memcpy (*data, whole_link + start, amount); + *datalen = amount; + } + } + else + { + err = netfs_attempt_readlink (user->user, node, *data); + *datalen = amount; + } + } + else + /* Read from a normal file. */ + err = netfs_attempt_read (user->user, node, start, datalen, *data); + if (offset == -1 && !err) user->po->filepointer += *datalen; - mutex_unlock (&user->po->np->lock); + + mutex_unlock (&node->lock); if (err && alloced) - vm_deallocate (mach_task_self (), (vm_address_t) *data, amount); + munmap (*data, amount); if (!err && alloced && (round_page (*datalen) < round_page (amount))) - vm_deallocate (mach_task_self (), - (vm_address_t) *data + round_page (*datalen), - round_page (amount) - round_page (*datalen)); + munmap (*data + round_page (*datalen), + round_page (amount) - round_page (*datalen)); return err; } - |