io.c File Reference

I/O functions. More...

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Defines
#define	STP_BUF_LEN   8191
Functions
void	dlog (const char *fmt,...)
	Logs data.
void	_stp_print_buf (const char *fmt,...)
	Print into the print buffer.
void	_stp_print_buf_init (void)
	Clear the print buffer.
void	_stp_print_symbol (const char *fmt, unsigned long address)
	Print addresses symbolically into the print buffer.
unsigned long	cur_ret_addr (struct pt_regs *regs)
	Get the current return address.
Variables
static const char *(*	_stp_kallsyms_lookup )(unsigned long addr, unsigned long *symbolsize, unsigned long *offset, char **modname, char *namebuf) = (void *)KALLSYMS_LOOKUP
	Lookup symbol.
static char	_stp_pbuf [8191+1]
	Static buffer for printing.
static int	_stp_pbuf_len = 8191

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Detailed Description

I/O functions.

Definition in file io.c.

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Function Documentation

void _stp_print_buf (  const char *  fmt,   ... )

Print into the print buffer. Like printf, except output goes into _stp_pbuf, which will contain the null-terminated output. Safe because overflowing _stp_pbuf is not allowed. Size is limited by length of print buffer. Parameters: fmt  A variable number of args. Note: Formatting output should never be done within a probe. Use at module exit time. See also: _stp_print_buf_init Definition at line 55 of file io.c. References _stp_pbuf. Referenced by _stp_print_symbol().

void _stp_print_buf_init (  void   )

Clear the print buffer. Output from _stp_print_buf() will accumulate in the buffer until this is called. Definition at line 72 of file io.c. References _stp_pbuf.

void _stp_print_symbol (  const char *  fmt, unsigned long  address )

Print addresses symbolically into the print buffer. Parameters: fmt  A variable number of args. address  The address to lookup. Note: Formatting output should never be done within a probe. Use at module exit time. Definition at line 85 of file io.c. References _stp_kallsyms_lookup, and _stp_print_buf().

unsigned long cur_ret_addr (  struct pt_regs *  regs  )

Get the current return address. Call from kprobes (not jprobes). Parameters: regs  The pt_regs saved by the kprobe. Returns: The return address saved in esp or rsp. Note: i386 and x86_64 only. Definition at line 112 of file io.c.

void dlog (  const char *  fmt,   ... )

Logs data. This function is compatible with printk. In fact it currently sends all output to vprintk, after sending "STP: ". This allows us to easily detect SystemTap output in the log file. Parameters: fmt  A variable number of args. Bug: Lines are limited in length by printk buffer. Todo: Needs replaced with something much faster that does not use the system log. Definition at line 16 of file io.c. Referenced by _stp_list_clear(), _stp_register_jprobes(), _stp_register_kprobes(), _stp_unregister_jprobes(), and _stp_unregister_kprobes().

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Variable Documentation

const char*(* _stp_kallsyms_lookup)(unsigned long addr, unsigned long *symbolsize, unsigned long *offset, char **modname, char *namebuf) = (void *)KALLSYMS_LOOKUP [static]

Lookup symbol. This simply calls the kernel function kallsyms_lookup(). That function is not exported, so this workaround is required. See the kernel source, kernel/kallsyms.c for more information. Definition at line 31 of file io.c. Referenced by _stp_print_symbol().

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