CRASH(ADM) UNIX System V
Name
crash - examine system images
Syntax
/etc/crash [ -d dumpfile ] [ -n namelist ] [ -w outputfile ]
Description
The crash command is used to examine the system memory image
of a live or a crashed system by formatting and printing
control structures, tables, and other information. Command
line arguments to crash are dumpfile, namelist, and
outputfile.
Dumpfile is the file containing the system memory image.
The default dumpfile is /dev/mem.
The text file namelist contains the symbol table information
needed for symbolic access to the system memory image to be
examined. The default namelist is /unix. If a system image
from another machine is to be examined, the corresponding
text file must be copied from that machine.
When the crash command is invoked, a session is initiated.
The output from a crash session is directed to outputfile.
The default outputfile is the standard output.
Input during a crash session is of the form:
function [argument ... ]
where function is one of the crash functions described in
the Functions section of this manual page, and arguments are
qualifying data that indicate which items of the system
image are to be printed.
The default for process-related items is the current process
for a running system and the process that was running at the
time of the crash for a crashed system. If the contents of
a table are being dumped, the default is all active table
entries.
The following function options are available to crash
functions wherever they are semantically valid.
-e Display every entry in a table.
-f Display the full structure.
-p Interpret all address arguments in the command line as
physical addresses.
-s process
Specify a process slot other than the default.
-w file
Redirect the output of a function to file.
Note that if the -p option is used, all address and symbol
arguments explicitly entered on the command line will be
interpreted as physical addresses. If they are not physical
addresses, results will be inconsistent.
The functions mode, defproc, and redirect correspond to the
function options -p, -s, and -w. The mode function may be
used to set the address translation mode to physical or
virtual for all subsequently entered functions; defproc sets
the value of the process slot argument for subsequent
functions; and redirect redirects all subsequent output.
Output from crash functions may be piped to another program
in the following way:
function [argument ... ]!shell_command
For example,
mount ! grep rw
will write all mount table entries with an rw flag to the
standard output. The redirection option (-w) cannot be used
with this feature.
Depending on the context of the function, numeric arguments
will be assumed to be in a specific radix. Counts are
assumed to be decimal. Addresses are always hexadecimal.
Table slot arguments are always decimal. Table slot
arguments larger than the size of the function table will
not be interpreted correctly. Use the findslot command to
translate from an address to a table slot number. Default
bases on all arguments may be overridden. The C conventions
for designating the bases of numbers are recognized. A
number that is usually interpreted as decimal will be
interpreted as hexadecimal if it is preceded by 0x and as
octal if it is preceded by 0. Decimal override is
designated by 0d, and binary by 0b.
Aliases for functions may be any uniquely identifiable
initial substring of the function name. Traditional aliases
of one letter, such as p for proc, remain valid.
Many functions accept different forms of entry for the same
argument. Requests for table information will accept a
table entry number or a range. A range of slot numbers may
be specified in the form a-b where a and b are decimal
numbers. An expression consists of two operands and an
operator. An operand may be an address, a symbol, or a
number; the operator may be +, -, *, /, &, or | . An
operand which is a number should be preceded by a radix
prefix if it is not a decimal number (0 for octal, 0x for
hexadecimal, 0b for binary). The expression must be
enclosed in parentheses (). Other functions will accept any
of these argument forms that are meaningful.
Two abbreviated arguments to crash functions are used
throughout. Both accept data entered in several forms.
They may be expanded into the following:
table_entry = table entry| range
start_addr = address| symbol| expression
Functions
? [-w file]
List available functions.
!cmd Escape to the shell to execute a command.
adv [-e] [-w file] [[-p]table_entry...]
Print the advertised table.
base [-w file] number ...
Print number in binary, octal, decimal, and
hexadecimal. A number in a radix other than decimal
should be preceded by a prefix that indicates its radix
as follows: 0x, hexadecimal; 0, octal; and 0b, binary.
buffer [-w file] [-format] bufferslot
or
buffer [-w file] [-format] [-p]start_addr
Alias: b.
Print the contents of a buffer in the designated
format. The following format designations are
recognized: -b, byte: -c, character; -d, decimal; -x,
hexadecimal; -o, octal; -r, directory; and -i, inode.
If no format is given, the previous format is used.
The default format at the beginning of a crash session
is hexadecimal.
bufhdr [-f] [-w file] [[-p]table_entry...]
Alias: buf.
Print system buffer headers.
callout [-w file]
Alias: c.
Print the callout table.
dballoc [-w file] [class ... ]
Print the dballoc table. If a class is entered, only
data block allocation information for that class will
be printed.
dbfree [-w file] [class ... ]
Print free streams data block headers. If a class is
entered, only data block headers for the class
specified will be printed.
dblock [-e] [-w file] [-c class...]
or
dblock [-e] [-w file] [[-p] table_entry...]
Print allocated streams data block headers. If the
class option (-c) is used, only data block headers for
the class specified will be printed.
defproc [-w file] [-c]
or
defproc [-w file] [slot]
Set the value of the process slot argument. The
process slot argument may be set to the current slot
number (-c) or the slot number may be specified. If no
argument is entered, the value of the previously set
slot number is printed. At the start of a crash
session, the process slot is set to the current
process.
dis [-w file] [-a] start_addr [count]
Disassemble from the start address for count
instructions. The default count is 1. The absolute
option (-a) specifies a non-symbolic disassembly.
ds [-w file] virtual_address ...
Print the data symbol whose address is closest to, but
not greater than, the address entered.
file [-e] [-w file] [[-p]table_entry...]
Alias: f.
Print the file table.
findaddr [-w file] table slot
Print the address of slot in table. Only tables
available to the size function are available to
findaddr.
findslot [-w file] virtual_address ...
Print the table, entry slot number, and offset for the
address entered. Only tables available to the size
function are available to findslot.
fs [-w file] [[-p]table_entry...]
Print the file system information table.
gdp [-e] [-f] [-w file] [[-p]table_entry...]
Print the gift descriptor protocol table.
gdt [-e] [-w file] [[-p] table_entry...]
Print the global descriptor table.
help [-w file] function ...
Print a description of the named function, including
syntax and aliases.
idt [-e] [-w file] [[-p]table_entry...]
Print the interrupt descriptor table.
inode [-e] [-f] [-w file] [[-p]table_entry...]
Alias: i.
Print the inode table, including file system switch
information.
kfp [-w file] [value]
Print the frame pointer for the start of a kernel stack
trace. If the value argument is supplied, the kfp is
set to that value.
lck [-e] [-w file] [[-p]table_entry...]
Alias: l.
Print record-locking information. If the -e option is
used or table address arguments are given, the record
lock list is printed. If no argument is entered,
information on locks relative to inodes is printed.
ldt [-e] [-w file] [-s process] [[-p]table_entry...]
Print the local descriptor table for the given process,
or for the current process if none is given.
linkblk [-e] [-w file] [[-p]table_entry...]
Print the linkblk table.
map [-w file] mapname ...
Print the map structure of mapname.
mbfree [-w file]
Print free streams message block headers.
mblock [-e] [-w filename] [[-p]table_entry...]
Print allocated streams message block headers.
mode [-w file] [mode]
Set address translation of arguments to virtual (v) or
physical (p) mode. If no mode argument is given, the
current mode is printed. At the start of a crash
session, the mode is virtual.
mount [-e] [-w file] [[-p]table_entry...]
Alias: m.
Print the mount table.
nm [-w file] symbol ...
Print value and type for the given symbol.
od [-p] [-w file] [-format] [-mode] [-s process] start_addr
[count]
Alias: rd.
Print count values starting at the start address in one
of the following formats: character (-c), decimal
(-d), hexadecimal (-x), octal (-o), ASCII (-a), or
hexadecimal/character (-h), and one of the following
modes: long (-l), short (-t), or byte (-b). The
default mode for character and ASCII formats is byte;
the default mode for decimal, hexadecimal, and octal
formats is long. The format -h prints both hexadecimal
and character representations of the addresses dumped;
no mode needs to be specified. When format or mode is
omitted, the previous value is used. At the start of a
crash session, the format is hexadecimal and the mode
is long. If no count is entered, 1 is assumed.
panic
Print the latest system notices, warnings, and panic
messages from the limited circular buffer kept in
memory.
pcb [-w file] [process]
Print the process control block (TSS) for the given
process. If no arguments are given, the active TSS for
the current process is printed.
pdt [-e] [-w file] [-s process] [-p] start_addr [count]
The page descriptor table of the designated memory
section and segment is printed. Alternatively, the
page descriptor table starting at the start address for
count entries is printed. If no count is entered, 1 is
assumed.
pfdat [-e] [-w file] [[-p]table_entry...]
Print the pfdata table.
proc [-e] [-f] [-w file] [[-p] table_entry ... #procid ...]
or
proc [-f] [-w file] [-r]
Alias: p.
Print the process table. Process table information may
be specified in two ways. First, any mixture of table
entries and process ids may be entered. Each process id
must be preceded by a #. Alternatively, process table
information for executable processes may be specified
with the executable option (-r). The full option (-f)
details most of the information in the process table as
well as the region table for that process.
qrun [-w file]
Print the list of scheduled streams queues.
queue [-e] [-w file] [[-p]table_entry...]
Print streams queues.
quit Alias: q.
Terminate the crash session.
rcvd [-e] [-f] [-w file] [[-p]table_entry...]
Print the receive descriptor table.
redirect [-w file] [-c]
or
redirect [-w file] [file]
Used with a file name, redirects output of a crash
session to the named file. If no argument is given,
the file name to which output is being redirected is
printed. Alternatively, the close option (-c) closes
the previously set file and redirects output to the
standard output.
region [-e] [-w file] [[-p]table_entry...]
Print the region table.
sdt [-e] [-w file] [-s process] section
or
sdt [-e] [-w file] [-s process] [-p] start_addr[count]
The segment descriptor table for the current process is
printed.
count
search [-p] [-w file] [-m mask] [-s process] pattern start_addr
Print the long words in memory that match pattern,
beginning at the start address for count long words.
The mask is anded (&) with each memory word and the
result compared against the pattern. The mask defaults
to 0xffffffff.
size [-w file] [-x] [structure_name ... ]
Print the size of the designated structure. The (-x)
option prints the size in hexadecimal. If no argument
is given, a list of the structure names for which sizes
are available is printed.
sndd [-e] [-f] [-w file] [[-p]table_entry...]
Print the send descriptor table.
srmount [-e] [-w file] [[-p]table_entry...]
Print the server mount table.
stack [-w file] [process]
Alias: s.
Dump stack. If no arguments are entered, the kernel
stack for the current process is printed. The
interrupt stack and the stack for the current process
are not available on a running system.
stat [-w file]
Print system statistics.
stream [-e] [-f] [-w file] [[-p]table_entry...]
Print the streams table.
strstat [-w file]
Print streams statistics.
trace [-w file] [-r] [process]
Alias: t.
Print kernel stack trace. The kfp value is used with
the -r option.
ts [-w file] virtual_address ...
Print closest text symbol to the designated address.
tty [-e] [-f] [-w file] [-ttype[[-p]table_entry...]]
Valid types: co, c1, c2 (console, com1, com2).
Print the tty table. If no arguments are given, the tty
table for the console is printed. If the -t option is
used, the table for the single tty type specified is
printed. If no argument follows the type option, all
entries in the table are printed. A single tty entry
may be specified from the start address.
user [-f] [-w file] [process]
Alias: u.
Print the ublock for the designated process.
var [-w file]
Alias: v.
Print the tunable system parameters.
vtop [-w file] [-s process] start_addr...
Print the physical address translation of the virtual
start address.
Files
/dev/mem system image of currently running system
(printed 8/23/89) CRASH(ADM)