Re: [Qemu-devel] Implement Xfer:auxv:read in gdb stub

[Jan Kiszka]

On 2015-06-24 08:34, Bhushan Attarde wrote:
> This patch implements support for "Xfer:auxv:read" to provide auxiliary vector
> information to clients which relies on it.
> 
> For example: AT_ENTRY in auxiliary vector provides the entry point 
> information.
> Client can use this information to compare it with entry point mentioned in 
> executable to calculate load offset and then update the load addresses
> accordingly.
> 
> 
> Signed-off-by: Bhushan Attarde <address@hidden>
> ---
> diff --git a/gdbstub.c b/gdbstub.c
> index cea2a84..e7db84a 100644
> --- a/gdbstub.c
> +++ b/gdbstub.c
> @@ -1153,6 +1153,7 @@ static int gdb_handle_packet(GDBState *s, const char 
> *line_buf)
>              if (cc->gdb_core_xml_file != NULL) {
>                  pstrcat(buf, sizeof(buf), ";qXfer:features:read+");
>              }
> +            pstrcat(buf, sizeof(buf), ";qXfer:auxv:read+");

Is this code block restricted to CONFIG_USER_ONLY? It should be because
the feature implementation is. Sorry, too lazy to check the full
context, and the patch doesn't tell it.

Jan

>              put_packet(s, buf);
>              break;
>          }
> @@ -1199,6 +1200,50 @@ static int gdb_handle_packet(GDBState *s, const char 
> *line_buf)
>              put_packet_binary(s, buf, len + 1);
>              break;
>          }
> +#ifdef CONFIG_USER_ONLY
> +        if (strncmp(p, "Xfer:auxv:read:", 15) == 0) {
> +            TaskState *ts = s->c_cpu->opaque;
> +            target_ulong auxv = ts->info->saved_auxv;
> +            target_ulong auxv_len = ts->info->auxv_len;
> +            char *ptr;
> +
> +            p += 15;
> +            while (*p && *p != ':') {
> +                p++;
> +            }
> +            p++;
> +
> +            addr = strtoul(p, (char **)&p, 16);
> +            if (*p == ',') {
> +                p++;
> +            }
> +            len = strtoul(p, (char **)&p, 16);
> +
> +            ptr = lock_user(VERIFY_READ, auxv, auxv_len, 0);
> +            if (ptr == NULL) {
> +                break;
> +            }
> +
> +            if (addr > len) {
> +                snprintf(buf, sizeof(buf), "E00");
> +                put_packet(s, buf);
> +                break;
> +            }
> +            if (len > (MAX_PACKET_LENGTH - 5) / 2) {
> +                len = (MAX_PACKET_LENGTH - 5) / 2;
> +            }
> +            if (len < auxv_len - addr) {
> +                buf[0] = 'm';
> +                len = memtox(buf + 1, ptr + addr, len);
> +            } else {
> +                buf[0] = 'l';
> +                len = memtox(buf + 1, ptr + addr, auxv_len - addr);
> +            }
> +            put_packet_binary(s, buf, len + 1);
> +            unlock_user(ptr, auxv, len);
> +            break;
> +        }
> +#endif /* !CONFIG_USER_ONLY */
>          if (is_query_packet(p, "Attached", ':')) {
>              put_packet(s, GDB_ATTACHED);
>              break;
> 
> 
> 
> 

-- 
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