diff options
Diffstat (limited to 'runtime/io.c')
| -rw-r--r-- | runtime/io.c | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/runtime/io.c b/runtime/io.c index 8756a48d..16343bef 100644 --- a/runtime/io.c +++ b/runtime/io.c @@ -1,3 +1,8 @@ +/* -*- linux-c -*- */ +/** @file io.c + * @brief I/O functions + */ + /** Logs data. * This function is compatible with printk. In fact it currently * sends all output to vprintk, after sending "STP: ". This allows @@ -18,6 +23,11 @@ void dlog (const char *fmt, ...) } +/** 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. + */ static const char * (*_stp_kallsyms_lookup)(unsigned long addr, unsigned long *symbolsize, unsigned long *offset, @@ -26,10 +36,22 @@ static const char * (*_stp_kallsyms_lookup)(unsigned long addr, #define STP_BUF_LEN 8191 -/* FIXME. These need to be per-cpu */ +/** Static buffer for printing */ static char _stp_pbuf[STP_BUF_LEN+1]; static int _stp_pbuf_len = STP_BUF_LEN; +/** 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. + * + * @param fmt A variable number of args. + * @note Formatting output should never be done within + * a probe. Use at module exit time. + * @sa _stp_print_buf_init + */ + void _stp_print_buf (const char *fmt, ...) { int num; @@ -42,12 +64,24 @@ void _stp_print_buf (const char *fmt, ...) _stp_pbuf_len -= num; } +/** Clear the print buffer. + * Output from _stp_print_buf() will accumulate in the buffer + * until this is called. + */ + void _stp_print_buf_init (void) { _stp_pbuf_len = STP_BUF_LEN; _stp_pbuf[0] = 0; } +/** Print addresses symbolically into the print buffer. + * @param fmt A variable number of args. + * @param address The address to lookup. + * @note Formatting output should never be done within + * a probe. Use at module exit time. + */ + void _stp_print_symbol(const char *fmt, unsigned long address) { char *modname; @@ -68,6 +102,12 @@ void _stp_print_symbol(const char *fmt, unsigned long address) } } +/** Get the current return address. + * Call from kprobes (not jprobes). + * @param regs The pt_regs saved by the kprobe. + * @return The return address saved in esp or rsp. + * @note i386 and x86_64 only. + */ unsigned long cur_ret_addr (struct pt_regs *regs) { |