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GNU/Linux |
CentOS 5.2 |
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stapfuncs(5) |
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stapfuncs − systemtap functions
The following
sections enumerate the public functions provided by standard
tapsets installed under /usr/share/systemtap/tapset. Each
function is described with a signature, and its
behavior/restrictions. The signature line includes the name
of the function, the type of its return value (if any), and
the names and types of all parameters. The syntax is the
same as printed with the stap option
−p2. Examples:
example1:long (v:string, k:long)
In function "example1", do something with the given string and integer. Return some integer.
example2:unknown ()
In function "example2", do something. There is no explicit return value and take no parameters.
PRINTING
log:unknown (msg:string)
Writes the given string to the common trace buffer. Append an implicit end-of-line. Deprecated. Please use the faster print functions.
warn:unknown (msg:string)
Write the given string to the warning stream. Append an implicit end-of-line. staprun prepends the string "WARNING:".
error:unknown (msg:string)
An error has occurred. Write the given string to the error stream. Append an implicit end-of-line. staprun prepends the string "ERROR:". Block any further execution of statements in this probe. If the number of errors so far exceeds the MAXERRORS parameter, also trigger an exit().
exit:unknown ()
Enqueue a request to shut down the systemtap session. This does not unwind the current probe handler, nor block new probe handlers. staprun will shortly respond to the request and initiate an orderly shutdown.
CONVERSIONS
These functions access kernel or user-space data. They try
to validate the supplied addresses, and can thus result in
errors if the pointers are invalid, or if a user-space
access would cause a fault.
kernel_string:string (addr:long)
Copy a 0-terminated string from kernel space at given address.
kernel_string_n:string (addr:long, n:long)
Similar with kernel_string, except that not more than n bytes are copied. Thus, if there are null bytes among the first n bytes, it is same as kernel_string(addr). If not, n bytes will be copied and a null byte will be padded to the end.
kernel_long:long (addr:long)
Copy a long from kernel space at given address.
kernel_int:long (addr:long)
Copy an int from kernel space at given address.
kernel_short:long (addr:long)
Copy a short from kernel space at given address.
kernel_char:long (addr:long)
Copy a char from kernel space at given address.
user_string:string (addr:long)
Copy a string from user space at given address. If the access would fault, return "<unknown>" and signal no errors.
user_string2:string (addr:long, err_msg:string)
Copy a string from user space at given address. If the access would fault, return instead the err_msg value.
user_string_warn:string (addr:long)
Copy a string from user space at given address. If the access would fault, signal a warning and return "<unknown>".
STRING
strlen:long (str:string)
Return the number of characters in str.
substr:string (str:string,start:long, stop:long)
Return the substring of str starting from character start and ending at character stop.
isinstr:long (s1:string, s2:string)
Return 1 if string s1 contains string s2, returns 0 otherwise.
strtol:long (str:string, base:long)
Convert the string representation of a number to a long using the numbering system specified by base. For example, strtol("1000", 16) returns 4096. Returns 0 if the string cannot be converted.
tokenize:string (str:string, delim:string)
Return the next token in the given str string, where the tokens are delimited by one of the characters in the delim string. If the str string is not blank, it returns the first token. If the str string is blank, it returns the next token in the string passed in the previous call to tokenize. If no delimiter is found, the entire remaining str string is returned. Returns blank when no more tokens are left.
TIMESTAMP
get_cycles:long ()
Return the processor cycle counter value, or 0 if unavailable.
gettimeofday_ns:long ()
Return the number of nanoseconds since the UNIX epoch.
gettimeofday_us:long ()
Return the number of microseconds since the UNIX epoch.
gettimeofday_ms:long ()
Return the number of milliseconds since the UNIX epoch.
gettimeofday_s:long ()
Return the number of seconds since the UNIX epoch.
CONTEXT
INFO
cpu:long ()
Return the current cpu number.
execname:string ()
Return the name of the current process.
pexecname:string()
Return the name of the parent process.
tid:long ()
Return the id of the current thread.
pid:long ()
Return the id of the current process.
ppid:long ()
Return the id of the parent process.
uid:long ()
Return the uid of the current process.
euid:long ()
Return the effective uid of the current process.
gid:long ()
Return the gid of the current process.
egid:long ()
Return the effective gid of the current process.
print_regs:unknown ()
Print a register dump.
backtrace:string ()
Return a string of hex addresses that are a backtrace of the stack. It may be truncated due to maximum string length.
print_stack:unknown (bt:string)
Perform a symbolic lookup of the addresses in the given string, which is assumed to be the result of a prior call to backtrace(). Print one line per address, including the address, the name of the function containing the address, and an estimate of its position within that function. Return nothing.
print_backtrace:unknown ()
Equivalent to print_stack(backtrace()), except that deeper stack nesting may be supported. Return nothing.
pp:string ()
Return the probe point associated with the currently running probe handler, including alias and wildcard expansion effects.
probefunc:string ()
Return the probe point’s function name, if known.
probemod:string ()
Return the probe point’s module name, if known.
target:long ()
Return the pid of the target process.
is_return:long ()
Return 1 if the probe point is a return probe. Deprecated.
TARGET_SET
target_set_pid:long (tid:long)
Return whether the given process-id is within the "target set", that is whether it is a descendent of the top-level target() process.
target_set_report:unknown ()
Print a report about the target set, and their ancestry.
ERRNO
errno_str:string (e:long)
Return the symbolic string associated with the given error code, like "ENOENT" for the number 2, or "E#3333" for an out-of-range value like 3333.
TASK
These functions return data about a task. They all require a
task handle as input, such as the value return by
task_current() or the variables prev_task and next_task in
the scheduler.ctxswitch probe alias.
task_current:long()
Return the task_struct of the current process.
task_parent:long(task:long)
Return the parent task_struct of the given task.
task_state:long(task:long)
Return the state of the given task, which can be one of the following:
TASK_RUNNING 0
TASK_INTERRUPTIBLE 1
TASK_UNINTERRUPTIBLE 2
TASK_STOPPED 4
TASK_TRACED 8
EXIT_ZOMBIE 16
EXIT_DEAD 32
task_execname:string(task:long)
Return the name of the given task.
task_pid:long(task:long)
Return the process id of the given task.
task_tid:long(task:long)
Return the thread id of the given task.
task_gid:long(task:long)
Return the group id of the given task.
task_egid:long(task:long)
Return the effective group id of the given task.
task_uid:long(task:long)
Return the user id of the given task.
task_euid:long(task:long)
Return the effective user id of the given task.
task_prio:long(task:long)
Return the priority of the given task.
task_nice:long(task:long)
Return the nice value of the given task.
task_cpu:long(task:long)
Return the scheduled cpu for the given task.
task_open_file_handles:long(task:long)
Return the number of open file handles for the given task.
task_max_file_handles:long(task:long)
Return the maximum number of file handles for the given task.
QUEUE_STATS
The queue_stats tapset provides functions that, given
notifications of elementary queuing events (wait, run,
done), tracks averages such as queue length, service and
wait times, utilization. The following three functions
should be called from appropriate probes, in sequence.
qs_wait:unknown (qname:string)
Record that a new request was enqueued for the given queue name.
qs_run:unknown (qname:string)
Record that a previously enqueued request was removed from the given wait queue and is now being serviced.
qs_done:unknown (qname:string)
Record that a request originally from the given queue has completed being serviced.
Functions with
the prefix qsq_ are for querying the statistics
averaged since the first queue operation (or when
qsq_start was called). Since statistics are often
fractional, a scale parameter is multiplies the result to a
more useful scale. For some fractions, a scale of 100 will
usefully return percentage numbers.
qsq_start:unknown (qname:string)
Reset the statistics counters for the given queue, and start tracking anew from this moment.
qsq_print:unknown (qname:string)
Print a line containing a selection of the given queue’s statistics.
qsq_utilization:long (qname:string, scale:long)
Return the fraction of elapsed time when the resource was utilized.
qsq_blocked:long (qname:string, scale:long)
Return the fraction of elapsed time when the wait queue was used.
qsq_wait_queue_length:long (qname:string, scale:long)
Return the average length of the wait queue.
qsq_service_time:long (qname:string, scale:long)
Return the average time required to service a request.
qsq_wait_time:long (qname:string, scale:long)
Return the average time a request took from being enqueued to completed.
qsq_throughput:long (qname:string, scale:long)
Return the average rate of requests per scale units of time.
INDENT
The indent tapset provides functions to generate indented
lines for nested kinds of trace messages. Each line contains
a relative timestamp, and the process name / pid.
thread_indent:string (delta:long)
Return a string with an appropriate indentation for this thread. Call it with a small positive or matching negative delta. If this is the outermost, initial level of indentation, reset the relative timestamp base to zero.
thread_timestamp:long ()
Return an absolute timestamp value for use by the indentation function. The default function uses gettimeofday_us
SYSTEM
system (cmd:string)
Runs a command on the system. The command will run in the background when the current probe completes.
NUMA
addr_to_node:long (addr:long)
Return which node the given address belongs to in a NUMA system.
CTIME
ctime:string (seconds:long)
Return a simple textual rendering (e.g., "Wed Jun 30 21:49:008 1993") of the given number of seconds since the epoch, as perhaps returned by gettimeofday_s().
PERFMON
read_counter:long (handle:long)
Returns the value for the processor’s performance counter for the associated handle. The body of the a perfmon probe should set record the handle being used for that event.
SOCKETS
These functions convert arguments in the socket tapset back
and forth between their numeric and string representations.
See stapprobes.socket(5) for details.
sock_prot_num2str:string (proto:long)
Returns the string representation of the given protocol value.
sock_prot_str2num:long (proto:string)
Returns the numeric value associated with the given protocol string.
sock_fam_num2str:string (family:long)
Returns the string representation of the given protocol family value.
sock_fam_str2num:long (family:string)
Returns the numeric value associated with the given protocol family string.
sock_state_num2str:string (state:long)
Returns the string representation of the given socket state value.
sock_state_str2num:long (state:string)
Returns the numeric value associated with the given socket state string.
sock_type_num2str:string (type:long)
Returns the string representation of the given socket type value.
sock_type_str2num:long (type:string)
Returns the numeric value associated with the given socket type string.
sock_flags_num2str:string (flags:long)
Returns the string representation of the given socket flags value.
msg_flags_num2str:string (flags:long)
Returns the string representation of the given message flags bit map.
INET
These functions convert between network (big-endian) and
host byte order, like their namesake C functions.
ntohll:long (x:long)
Convert from network to host byte order, 64-bit.
ntohl:long (x:long)
Convert from network to host byte order, 32-bit.
ntohs:long (x:long)
Convert from network to host byte order, 16-bit.
htonll:long (x:long)
Convert from host to network byte order, 64-bit.
htonl:long (x:long)
Convert from host to network byte order, 32-bit.
htons:long (x:long)
Convert from host to network byte order, 16-bit.
SIGNAL
get_sa_flags:long (act:long)
Returns the numeric value of sa_flags.
get_sa_handler:long (act:long)
Returns the numeric value of sa_handler.
sigset_mask_str:string (mask:long)
Returns the string representation of the sigset sa_mask.
is_sig_blocked:long (task:long, sig:long)
Returns 1 if the signal is currently blocked, or 0 if it is not.
sa_flags_str:string (sa_flags:long)
Returns the string representation of sa_flags.
sa_handler_str(handler)
Returns the string representation of sa_handler. If it is not SIG_DFL, SIG_IGN or SIG_ERR, it will return the address of the handler.
signal_str(num)
Returns the string representation of the given signal number.
/usr/share/systemtap/tapset
stap(1)
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stapfuncs(5) | |