freebsd-skq/lib/libsysdecode/sysdecode_mask.3
jhb 27ec61a437 Move mksubr from kdump into libsysdecode.
Restructure this script so that it generates a header of tables instead
of a source file.  The tables are included in a flags.c source file which
provides functions to decode various system call arguments.

For functions that decode an enumeration, the function returns a pointer
to a string for known values and NULL for unknown values.

For functions that do more complex decoding (typically of a bitmask), the
function accepts a pointer to a FILE object (open_memstream() can be used
as a string builder) to which decoded values are written.  If the
function operates on a bitmask, the function returns true if any bits
were decoded or false if the entire value was valid.  Additionally, the
third argument accepts a pointer to a value to which any undecoded bits
are stored.  This pointer can be NULL if the caller doesn't care about
remaining bits.

Convert kdump over to using decoder functions from libsysdecode instead of
mksubr.  truss also uses decoders from libsysdecode instead of private
lookup tables, though lookup tables for objects not decoded by kdump remain
in truss for now.  Eventually most of these tables should move into
libsysdecode as the automated table generation approach from mksubr is
less stale than the static tables in truss.

Some changes have been made to truss and kdump output:
- The flags passed to open() are now properly decoded in that one of
  O_RDONLY, O_RDWR, O_WRONLY, or O_EXEC is always included in a decoded
  mask.
- Optional arguments to open(), openat(), and fcntl() are only printed
  in kdump if they exist (e.g. the mode is only printed for open() if
  O_CREAT is set in the flags).
- Print argument to F_GETLK/SETLK/SETLKW in kdump as a pointer, not int.
- Include all procctl() commands.
- Correctly decode pipe2() flags in truss by not assuming full
  open()-like flags with O_RDONLY, etc.
- Decode file flags passed to *chflags() as file flags (UF_* and SF_*)
  rather than as a file mode.
- Fix decoding of quotactl() commands by splitting out the two command
  components instead of assuming the raw command value matches the
  primary command component.

In addition, truss and kdump now build without triggering any warnings.
All of the sysdecode manpages now include the required headers in the
synopsis.

Reviewed by:	kib (several older versions), wblock (manpages)
MFC after:	2 months
Differential Revision:	https://reviews.freebsd.org/D7847
2016-10-17 22:37:07 +00:00

217 lines
7.2 KiB
Groff

.\"
.\" Copyright (c) 2016 John Baldwin <jhb@FreeBSD.org>
.\" All rights reserved.
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.Dd October 17, 2016
.Dt sysdecode_mask 3
.Os
.Sh NAME
.Nm sysdecode_mask ,
.Nm sysdecode_accessmode ,
.Nm sysdecode_capfcntlrights ,
.Nm sysdecode_fcntl_fileflags ,
.Nm sysdecode_fileflags ,
.Nm sysdecode_filemode ,
.Nm sysdecode_flock_operation ,
.Nm sysdecode_getfsstat_flags ,
.Nm sysdecode_mlockall_flags ,
.Nm sysdecode_mmap_flags ,
.Nm sysdecode_mmap_prot ,
.Nm sysdecode_mount_flags ,
.Nm sysdecode_msg_flags ,
.Nm sysdecode_msync_flags ,
.Nm sysdecode_open_flags ,
.Nm sysdecode_pipe2_flags ,
.Nm sysdecode_reboot_howto ,
.Nm sysdecode_rfork_flags ,
.Nm sysdecode_semget_flags ,
.Nm sysdecode_sendfile_flags ,
.Nm sysdecode_shmat_flags ,
.Nm sysdecode_socket_type ,
.Nm sysdecode_thr_create_flags ,
.Nm sysdecode_umtx_cvwait_flags ,
.Nm sysdecode_umtx_rwlock_flags ,
.Nm sysdecode_vmprot ,
.Nm sysdecode_wait4_options ,
.Nm sysdecode_wait6_options
.Nd print name of various bitmask values
.Sh LIBRARY
.Lb libsysdecode
.Sh SYNOPSIS
.In sys/types.h
.In stdbool.h
.In sysdecode.h
.Ft bool
.Fn sysdecode_access_mode "FILE *fp" "int mode" "int *rem"
.Ft bool
.Fn sysdecode_cap_fcntlrights "FILE *fp" "uint32_t rights" "uint32_t *rem"
.Ft bool
.Fn sysdecode_fcntl_fileflags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_fileflags "FILE *fp" "fflags_t flags" "fflags_t *rem"
.Ft bool
.Fn sysdecode_filemode "FILE *fp" "int mode" "int *rem"
.Ft bool
.Fn sysdecode_flock_operation "FILE *fp" "int operation" "int *rem"
.Ft bool
.Fn sysdecode_mlockall_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_mmap_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_mmap_prot "FILE *fp" "int prot" "int *rem"
.Ft bool
.Fn sysdecode_mount_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_msg_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_msync_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_open_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_pipe2_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_reboot_howto "FILE *fp" "int howto" "int *rem"
.Ft bool
.Fn sysdecode_rfork_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_semget_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_sendfile_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_shmat_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_socket_type "FILE *fp" "int type" "int *rem"
.Ft bool
.Fn sysdecode_thr_create_flags "FILE *fp" "int flags" "int *rem"
.Ft bool
.Fn sysdecode_umtx_cvwait_flags "FILE *fp" "u_long flags" "u_long *rem"
.Ft bool
.Fn sysdecode_umtx_rwlock_flags "FILE *fp" "u_long flags" "u_long *rem"
.Ft bool
.Fn sysdecode_vmprot "FILE *fp" "int type" "int *rem"
.Ft bool
.Fn sysdecode_wait4_options "FILE *fp" "int options" "int *rem"
.Ft bool
.Fn sysdecode_wait6_options "FILE *fp" "int options" "int *rem"
.Sh DESCRIPTION
The
.Nm
functions are used to generate a text description of an integer value
built from a mask of bitfields.
The text description lists the C macros for field values joined by pipe
.Sq |
characters matching the format used in C source code.
Most of the values decoded by these functions are passed as arguments to
system calls,
though some of these values are used internally in the kernel.
.Pp
Each function writes the text description to
.Fa fp .
The second argument should contain the integer value to be decoded.
The
.Fa rem
argument is set to the value of any bits that were not decoded
.Pq bit fields that do not have a corresponding C macro .
.Fa rem
may be set to
.Dv NULL
if the caller does not need this value.
Each function returns
.Dv true
if any bit fields in the value were decoded and
.Dv false
if no bit fields were decoded.
.Pp
Most of these functions decode an argument passed to a system call:
.Bl -column "Fn sysdecode_flock_operation" "Xr cap_fcntls_limit 2"
.It Sy Function Ta Sy System Call Ta Sy Argument
.It Fn sysdecode_access_mode Ta Xr access 2 Ta Fa mode
.It Fn sysdecode_cap_fcntlrights Ta Xr cap_fcntls_limit 2 Ta Fa fcntlrights
.It Fn sysdecode_fileflags Ta Xr chflags 2 Ta Fa flags
.It Fn sysdecode_filemode Ta Xr chmod 2 , Xr open 2 Ta mode
.It Fn sysdecode_flock_operation Ta Xr flock 2 Ta Fa operation
.It Fn sysdecode_getfsstat_flags Ta Xr getfsstatflags 2 Ta Fa flags
.It Fn sysdecode_mlockall_flags Ta Xr mlockall 2 Ta Fa flags
.It Fn sysdecode_mmap_flags Ta Xr mmap 2 Ta Fa flags
.It Fn sysdecode_mmap_prot Ta Xr mmap 2 Ta Fa prot
.It Fn sysdecode_mount_flags Ta Xr mount 2 Ta Fa flags
.It Fn sysdecode_msg_flags Ta Xr recv 2 , Xr send 2 Ta Fa flags
.It Fn sysdecode_msync_flags Ta Xr msync 2 Ta Fa flags
.It Fn sysdecode_open_flags Ta Xr open 2 Ta Fa flags
.It Fn sysdecode_pipe2_flags Ta Xr pipe2 Ta Fa flags
.It Fn sysdecode_reboot_howto Ta Xr reboot 2 Ta Fa howto
.It Fn sysdecode_rfork_flags Ta Xr rfork 2 Ta Fa flags
.It Fn sysdecode_semget_flags Ta Xr semget 2 Ta Fa flags
.It Fn sysdecode_sendfile_flags Ta Xr sendfile 2 Ta Fa flags
.It Fn sysdecode_shmat_flags Ta Xr shmat 2 Ta Fa flags
.It Fn sysdecode_socket_type Ta Xr socket 2 Ta Fa type
.It Fn sysdecode_thr_create_flags Ta Xr thr_create 2 Ta Fa flags
.It Fn sysdecode_wait4_options Ta Xr wait4 2 Ta Fa options
.It Fn sysdecode_wait6_options Ta Xr wait6 2 Ta Fa options
.El
.Pp
Other functions decode the values described below:
.Bl -tag -width ".Fn sysdecode_umtx_cvwait_flags"
.It Fn sysdecode_fcntl_fileflags
The file flags used with the
.Dv F_GETFL
and
.Dv F_SETFL
.Xr fcntl 2
commands.
.It Fn sysdecode_umtx_cvwait_flags
The
.Fa val
argument to
.Xr _umtx_op 2
for
.Dv UMTX_OP_CV_WAIT
operations.
.It Fn sysdecode_umtx_rwlock_flags
The
.Fa val
argument to
.Xr _umtx_op 2
for
.Dv UMTX_OP_RW_RDLOCK
operations.
.It Fn sysdecode_vmprot
The memory protection flags stored in
.Vt vm_prot_t
variables.
.El
.Sh RETURN VALUES
The
.Nm
functions return
.Dv true
if any bit fields in the value were decoded and
.Dv false
if no bit fields were decoded.
.Sh SEE ALSO
.Xr sysdecode 3 ,
.Xr sysdecode_enum 3