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218 lines
10 KiB
C
218 lines
10 KiB
C
/* Facilities for FUSE-backed file system tests.
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Copyright (C) 2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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/* To run FUSE tests under valgrind, pass the
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--sim-hints=fuse-compatible option to valgrind. This option tells
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valgrind that additional system calls effectively call back into
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the current program. */
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#ifndef SUPPORT_FUSE_H
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#define SUPPORT_FUSE_H
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <support/bundled/linux/include/uapi/linux/fuse.h>
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/* This function must be called furst, before support_fuse_mount, to
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prepare unprivileged mounting. */
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void support_fuse_init (void);
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/* This function can be called instead of support_fuse_init. It does
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not use mount and user namespaces, so it requires root privileges,
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and cleanup after testing may be incomplete. This is intended only
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for test development. */
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void support_fuse_init_no_namespace (void);
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/* Opaque type for tracking FUSE mount state. */
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struct support_fuse;
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/* This function disables a mount point created using
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support_fuse_mount. */
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void support_fuse_unmount (struct support_fuse *) __nonnull ((1));
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/* This function is called on a separate thread after calling
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support_fuse_mount. F is the mount state, and CLOSURE the argument
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that was passed to support_fuse_mount. The callback function is
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expected to call support_fuse_next to read packets from the kernel
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and handle them according to the test's need. */
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typedef void (*support_fuse_callback) (struct support_fuse *f, void *closure);
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/* This function creates a new mount point, implemented by CALLBACK.
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CLOSURE is passed to CALLBACK as the second argument. */
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struct support_fuse *support_fuse_mount (support_fuse_callback callback,
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void *closure)
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__nonnull ((1)) __attr_dealloc (support_fuse_unmount, 1);
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/* This function returns the path to the mount point for F. The
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returned string is valid until support_fuse_unmount (F) is called. */
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const char * support_fuse_mountpoint (struct support_fuse *f) __nonnull ((1));
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/* Renders the OPCODE as a string (FUSE_* constant. The caller must
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free the returned string. */
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char * support_fuse_opcode (uint32_t opcode) __attr_dealloc_free;
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/* Use to provide a checked cast facility. Use the
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support_fuse_in_cast macro below. */
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void *support_fuse_cast_internal (struct fuse_in_header *, uint32_t)
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__nonnull ((1));
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void *support_fuse_cast_name_internal (struct fuse_in_header *, uint32_t,
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size_t skip, char **name)
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__nonnull ((1));
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/* The macro expansion support_fuse_in_cast (P, TYPE) casts the
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pointer INH to the appropriate type corresponding to the FUSE_TYPE
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opcode. It fails (terminates the process) if INH->opcode does not
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match FUSE_TYPE. The type of the returned pointer matches that of
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the FUSE_* constant.
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Maintenance note: Adding support for additional struct fuse_*_in
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types is generally easy, except when there is trailing data after
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the struct (see below for support_fuse_cast_name, for example), and
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the kernel has changed struct sizes over time. This has happened
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recently with struct fuse_setxattr_in, and would require special
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handling if implemented. */
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#define support_fuse_payload_type_INIT struct fuse_init_in
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#define support_fuse_payload_type_LOOKUP char
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#define support_fuse_payload_type_OPEN struct fuse_open_in
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#define support_fuse_payload_type_READ struct fuse_read_in
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#define support_fuse_payload_type_SETATTR struct fuse_setattr_in
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#define support_fuse_payload_type_WRITE struct fuse_write_in
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#define support_fuse_cast(typ, inh) \
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((support_fuse_payload_type_##typ *) \
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support_fuse_cast_internal ((inh), FUSE_##typ))
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/* Same as support_fuse_cast, but also writes the passed name to *NAMEP. */
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#define support_fuse_payload_name_type_CREATE struct fuse_create_in
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#define support_fuse_payload_name_type_MKDIR struct fuse_mkdir_in
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#define support_fuse_cast_name(typ, inh, namep) \
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((support_fuse_payload_name_type_##typ *) \
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support_fuse_cast_name_internal \
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((inh), FUSE_##typ, sizeof (support_fuse_payload_name_type_##typ), \
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(namep)))
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/* This function should be called from the callback function. It
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returns NULL if the mount point has been unmounted. The result can
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be cast using support_fuse_in_cast. The pointer is invalidated
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with the next call to support_fuse_next.
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Typical use involves handling some basics using the
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support_fuse_handle_* building blocks, following by a switch
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statement on the result member of the returned struct, to implement
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what a particular test needs. Casts to payload data should be made
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using support_fuse_in_cast.
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By default, FUSE_FORGET responses are filtered. See
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support_fuse_filter_forget for turning that off. */
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struct fuse_in_header *support_fuse_next (struct support_fuse *f)
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__nonnull ((1));
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/* This function can be called from a callback function to handle
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basic aspects of directories (OPENDIR, GETATTR, RELEASEDIR).
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inh->nodeid is used as the inode number for the directory. This
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function must be called after support_fuse_next. */
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bool support_fuse_handle_directory (struct support_fuse *f) __nonnull ((1));
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/* This function can be called from a callback function to handle
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access to the mount point itself, after call support_fuse_next. */
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bool support_fuse_handle_mountpoint (struct support_fuse *f) __nonnull ((1));
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/* If FILTER_ENABLED, future support_fuse_next calls will not return
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FUSE_FORGET events (and simply discared them, as they require no
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reply). If !FILTER_ENABLED, the callback needs to handle
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FUSE_FORGET events and call support_fuse_no_reply. */
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void support_fuse_filter_forget (struct support_fuse *f, bool filter_enabled)
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__nonnull ((1));
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/* This function should be called from the callback function after
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support_fuse_next returned a non-null pointer. It sends out a
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response packet on the FUSE device with the supplied payload data. */
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void support_fuse_reply (struct support_fuse *f,
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const void *payload, size_t payload_size)
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__nonnull ((1)) __attr_access ((__read_only__, 2, 3));
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/* This function should be called from the callback function. It
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replies to a request with an error indicator. ERROR must be positive. */
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void support_fuse_reply_error (struct support_fuse *f, uint32_t error)
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__nonnull ((1));
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/* This function should be called from the callback function. It
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sends out an empty (but success-indicating) reply packet. */
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void support_fuse_reply_empty (struct support_fuse *f) __nonnull ((1));
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/* Do not send a reply. Only to be used after a support_fuse_next
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call that returned a FUSE_FORGET event. */
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void support_fuse_no_reply (struct support_fuse *f) __nonnull ((1));
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/* Specific reponse preparation functions. The returned object can be
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updated as needed. If a NODEID argument is present, it will be
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used to set the inode and FUSE nodeid fields. Without such an
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argument, it is initialized from the current request (if the reply
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requires this field). This function must be called after
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support_fuse_next. The actual response must be sent using
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support_fuse_reply_prepared (or a support_fuse_reply_error call can
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be used to cancel the response). */
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struct fuse_entry_out *support_fuse_prepare_entry (struct support_fuse *f,
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uint64_t nodeid)
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__nonnull ((1));
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struct fuse_attr_out *support_fuse_prepare_attr (struct support_fuse *f)
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__nonnull ((1));
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/* Similar to the other support_fuse_prepare_* functions, but it
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prepares for two response packets. They can be updated through the
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pointers written to *OUT_ENTRY and *OUT_OPEN prior to calling
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support_fuse_reply_prepared. */
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void support_fuse_prepare_create (struct support_fuse *f,
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uint64_t nodeid,
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struct fuse_entry_out **out_entry,
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struct fuse_open_out **out_open)
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__nonnull ((1, 3, 4));
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/* Prepare sending a directory stream. Must be called after
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support_fuse_next and before support_fuse_dirstream_add. */
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struct support_fuse_dirstream;
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struct support_fuse_dirstream *support_fuse_prepare_readdir (struct
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support_fuse *f);
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/* Adds directory using D_INO, D_OFF, D_TYPE, D_NAME to the directory
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stream D. Must be called after support_fuse_prepare_readdir.
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D_OFF is the offset of the next directory entry, not the current
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one. The first entry has offset zero. The first requested offset
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can be obtained from the READ payload (struct fuse_read_in) prior
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to calling this function.
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Returns true if the entry could be added to the buffer, or false if
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there was insufficient room. Sending the buffer is delayed until
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support_fuse_reply_prepared is called. */
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bool support_fuse_dirstream_add (struct support_fuse_dirstream *d,
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uint64_t d_ino, uint64_t d_off,
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uint32_t d_type,
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const char *d_name);
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/* Send a prepared response. Must be called after one of the
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support_fuse_prepare_* functions and before the next
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support_fuse_next call. */
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void support_fuse_reply_prepared (struct support_fuse *f) __nonnull ((1));
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#endif /* SUPPORT_FUSE_H */
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