[ktap] Re: [PATCH 1/3] symbol: replace find_symbol() by get_dso_symbols()
- From: Jovi Zhangwei <jovi.zhangwei@xxxxxxxxx>
- To: ktap <ktap@xxxxxxxxxxxxx>
- Date: Thu, 14 Nov 2013 10:37:27 +0800
Hi Azat,
Thanks your patches.
On Thu, Nov 14, 2013 at 3:13 AM, Azat Khuzhin <a3at.mail@xxxxxxxxx> wrote:
> Old find_symbol() just find symbol by name, the new one
> get_dso_symbols() will return all symbols/notes.
>
> And user of this functions, will match name/pattern by itself.
>
> For now get_dso_symbols() used like find_symbol(), this behaviour will
> be changed in next patches.
>
> Signed-off-by: Azat Khuzhin <a3at.mail@xxxxxxxxx>
> ---
> userspace/eventdef.c | 13 ++++++-
> userspace/symbol.c | 105
> +++++++++++++++++++++++++++++++++++++++++----------
> userspace/symbol.h | 25 +++++++++---
> 3 files changed, 117 insertions(+), 26 deletions(-)
>
> diff --git a/userspace/eventdef.c b/userspace/eventdef.c
> index 748ca10..13703c6 100644
> --- a/userspace/eventdef.c
> +++ b/userspace/eventdef.c
> @@ -333,6 +333,8 @@ static char *parse_events_resolve_symbol(char *event, int
> type)
> {
> char *colon, *end, *tail, *binary, *symbol;
> vaddr_t symbol_address;
> + struct dso_symbol *symbols = NULL;
> + size_t symbols_count, i;
>
> colon = strchr(event, ':');
> if (!colon)
> @@ -357,7 +359,16 @@ static char *parse_events_resolve_symbol(char *event,
> int type)
> symbol = strdup(colon + 1 /* skip ":" */);
> }
>
> - symbol_address = find_symbol(binary, symbol, type);
> + symbols_count = get_dso_symbols(&symbols, binary, type);
> + for (i = 0; i < symbols_count; ++i) {
> + if (strcmp(symbols[i].name, symbol))
> + continue;
> +
> + symbol_address = symbols[i].addr;
> + break;
> + }
> + free_dso_symbols(symbols, symbols_count);
> +
I have some concern on function get_dso_symbol, imagine one big binary
have 10000+ symbols,
then it's quite inefficient to allocate that symbols array, and
probably not necessarily.
How about use actor function? like below:
int uprobe_symbol_actor(const char *binary, const char *symbol,
unsigned long addr)
{
/* write to debufs */
...
}
nr = symbol_parse(binary, symbol, type, uprobe_symbol_actor);
if (!nr) {
/* no symbol found */
}
Then there don't need any dynamic memory allocation for symbols array.
(probably this would be more proper when consider to parse function arguments
and local variable in future, return a big symbols array cannot handle
this feature easily)
Jovi
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