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Re: [Qemu-devel] [PATCH RFC 1/4] log: Clean up misuse of Range for -dfil
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH RFC 1/4] log: Clean up misuse of Range for -dfilter |
Date: |
Sun, 19 Jun 2016 06:24:35 +0300 |
On Wed, Jun 15, 2016 at 10:41:47PM +0200, Markus Armbruster wrote:
> Range encodes an integer interval [a,b] as { begin = a, end = b + 1 },
> where a \in [0,2^64-1] and b \in [1,2^64]. Thus, zero end is to be
> interpreted as 2^64.
>
> The implementation of -dfilter (commit 3514552) uses Range
> differently: it encodes [a,b] as { begin = a, end = b }. The code
> works, but it contradicts the specification of Range in range.h.
>
> Switch to the specified representation. Since it can't represent
> [0,UINT64_MAX], we have to reject that now. Add a test for it.
>
> While we're rejecting anyway: observe that we reject -dfilter LOB..UPB
> where LOB > UPB when UPB is zero, but happily create an empty Range
> when it isn't. Reject it then, too, and add a test for it.
>
> While there, add a positive test for the problematic upper bound
> UINT64_MAX.
>
> Signed-off-by: Markus Armbruster <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
> ---
> tests/test-logging.c | 10 ++++++++++
> util/log.c | 28 +++++++++++++++-------------
> 2 files changed, 25 insertions(+), 13 deletions(-)
>
> diff --git a/tests/test-logging.c b/tests/test-logging.c
> index 440e75f..b6fa94e 100644
> --- a/tests/test-logging.c
> +++ b/tests/test-logging.c
> @@ -68,6 +68,16 @@ static void test_parse_range(void)
> g_assert(qemu_log_in_addr_range(0x2050));
> g_assert(qemu_log_in_addr_range(0x3050));
>
> + qemu_set_dfilter_ranges("0xffffffffffffffff-1", &error_abort);
> + g_assert(qemu_log_in_addr_range(UINT64_MAX));
> + g_assert_false(qemu_log_in_addr_range(UINT64_MAX - 1));
> +
> + qemu_set_dfilter_ranges("0..0xffffffffffffffff", &err);
> + error_free_or_abort(&err);
> +
> + qemu_set_dfilter_ranges("2..1", &err);
> + error_free_or_abort(&err);
> +
> qemu_set_dfilter_ranges("0x1000+onehundred", &err);
> error_free_or_abort(&err);
>
> diff --git a/util/log.c b/util/log.c
> index 32e4160..f811d61 100644
> --- a/util/log.c
> +++ b/util/log.c
> @@ -131,8 +131,8 @@ bool qemu_log_in_addr_range(uint64_t addr)
> if (debug_regions) {
> int i = 0;
> for (i = 0; i < debug_regions->len; i++) {
> - struct Range *range = &g_array_index(debug_regions, Range, i);
> - if (addr >= range->begin && addr <= range->end) {
> + Range *range = &g_array_index(debug_regions, Range, i);
> + if (addr >= range->begin && addr <= range->end - 1) {
> return true;
> }
> }
> @@ -158,7 +158,7 @@ void qemu_set_dfilter_ranges(const char *filter_spec,
> Error **errp)
> for (i = 0; ranges[i]; i++) {
> const char *r = ranges[i];
> const char *range_op, *r2, *e;
> - uint64_t r1val, r2val;
> + uint64_t r1val, r2val, lob, upb;
> struct Range range;
>
> range_op = strstr(r, "-");
> @@ -187,27 +187,29 @@ void qemu_set_dfilter_ranges(const char *filter_spec,
> Error **errp)
> (int)(r2 - range_op), range_op);
> goto out;
> }
> - if (r2val == 0) {
> - error_setg(errp, "Invalid range");
> - goto out;
> - }
>
> switch (*range_op) {
> case '+':
> - range.begin = r1val;
> - range.end = r1val + (r2val - 1);
> + lob = r1val;
> + upb = r1val + r2val - 1;
> break;
> case '-':
> - range.end = r1val;
> - range.begin = r1val - (r2val - 1);
> + upb = r1val;
> + lob = r1val - (r2val - 1);
> break;
> case '.':
> - range.begin = r1val;
> - range.end = r2val;
> + lob = r1val;
> + upb = r2val;
> break;
> default:
> g_assert_not_reached();
> }
> + if (lob > upb || (lob == 0 && upb == UINT64_MAX)) {
> + error_setg(errp, "Invalid range");
> + goto out;
> + }
> + range.begin = lob;
> + range.end = upb + 1;
> g_array_append_val(debug_regions, range);
> }
> out:
> --
> 2.5.5