Re: [PATCH v11 net-next 00/12] eBPF syscall, verifier, testsuite

On 09/10/2014 07:32 PM, Alexei Starovoitov wrote:

On Wed, Sep 10, 2014 at 2:03 AM, Daniel Borkmann [off-list ref] wrote:

quoted

quoted

             struct { /* anonymous struct used by BPF_PROG_LOAD command */
                 enum bpf_prog_type    prog_type;
                 __u32                 insn_cnt;
                 const struct bpf_insn *insns;
                 const char            *license;
                 __u32                 log_level; /* verbosity level of
eBPF verifier */
                 __u32                 log_size;  /* size of user buffer */
                 void                  *log_buf;  /* user supplied buffer
*/

What is log buffer? Would that mean the verifier will return an error
string if the program will not pass it, or if not, what other data?
I think the man page is missing how to examine the returned verifier
log buffer data.

yes. it's an error log (as text string for humans) from verifier.

I was confused due to the void pointer. But that also means that the text
string becomes part of the ABI; aren't eBPF specific error codes (perhaps
a tuple of [line + error code]), though ugly as well, but perhaps the better
solution to this [which user space can then map to an actual string]?