qemu/net/dump.c
Markus Armbruster 668f62ec62 error: Eliminate error_propagate() with Coccinelle, part 1
When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away.  Convert

    if (!foo(..., &err)) {
        ...
        error_propagate(errp, err);
        ...
        return ...
    }

to

    if (!foo(..., errp)) {
        ...
        ...
        return ...
    }

where nothing else needs @err.  Coccinelle script:

    @rule1 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
         if (
    (
    -        fun(args, &err, args2)
    +        fun(args, errp, args2)
    |
    -        !fun(args, &err, args2)
    +        !fun(args, errp, args2)
    |
    -        fun(args, &err, args2) op c1
    +        fun(args, errp, args2) op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    )
         }

    @rule2 forall@
    identifier fun, err, errp, lbl;
    expression list args, args2;
    expression var;
    binary operator op;
    constant c1, c2;
    symbol false;
    @@
    -    var = fun(args, &err, args2);
    +    var = fun(args, errp, args2);
         ... when != err
         if (
    (
             var
    |
             !var
    |
             var op c1
    )
            )
         {
             ... when != err
                 when != lbl:
                 when strict
    -        error_propagate(errp, err);
             ... when != err
    (
             return;
    |
             return c2;
    |
             return false;
    |
             return var;
    )
         }

    @depends on rule1 || rule2@
    identifier err;
    @@
    -    Error *err = NULL;
         ... when != err

Not exactly elegant, I'm afraid.

The "when != lbl:" is necessary to avoid transforming

         if (fun(args, &err)) {
             goto out
         }
         ...
     out:
         error_propagate(errp, err);

even though other paths to label out still need the error_propagate().
For an actual example, see sclp_realize().

Without the "when strict", Coccinelle transforms vfio_msix_setup(),
incorrectly.  I don't know what exactly "when strict" does, only that
it helps here.

The match of return is narrower than what I want, but I can't figure
out how to express "return where the operand doesn't use @err".  For
an example where it's too narrow, see vfio_intx_enable().

Silently fails to convert hw/arm/armsse.c, because Coccinelle gets
confused by ARMSSE being used both as typedef and function-like macro
there.  Converted manually.

Line breaks tidied up manually.  One nested declaration of @local_err
deleted manually.  Preexisting unwanted blank line dropped in
hw/riscv/sifive_e.c.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-35-armbru@redhat.com>
2020-07-10 15:18:08 +02:00

266 lines
6.9 KiB
C

/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "clients.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/iov.h"
#include "qemu/log.h"
#include "qemu/module.h"
#include "qemu/timer.h"
#include "qapi/visitor.h"
#include "net/filter.h"
typedef struct DumpState {
int64_t start_ts;
int fd;
int pcap_caplen;
} DumpState;
#define PCAP_MAGIC 0xa1b2c3d4
struct pcap_file_hdr {
uint32_t magic;
uint16_t version_major;
uint16_t version_minor;
int32_t thiszone;
uint32_t sigfigs;
uint32_t snaplen;
uint32_t linktype;
};
struct pcap_sf_pkthdr {
struct {
int32_t tv_sec;
int32_t tv_usec;
} ts;
uint32_t caplen;
uint32_t len;
};
static ssize_t dump_receive_iov(DumpState *s, const struct iovec *iov, int cnt)
{
struct pcap_sf_pkthdr hdr;
int64_t ts;
int caplen;
size_t size = iov_size(iov, cnt);
struct iovec dumpiov[cnt + 1];
/* Early return in case of previous error. */
if (s->fd < 0) {
return size;
}
ts = qemu_clock_get_us(QEMU_CLOCK_VIRTUAL);
caplen = size > s->pcap_caplen ? s->pcap_caplen : size;
hdr.ts.tv_sec = ts / 1000000 + s->start_ts;
hdr.ts.tv_usec = ts % 1000000;
hdr.caplen = caplen;
hdr.len = size;
dumpiov[0].iov_base = &hdr;
dumpiov[0].iov_len = sizeof(hdr);
cnt = iov_copy(&dumpiov[1], cnt, iov, cnt, 0, caplen);
if (writev(s->fd, dumpiov, cnt + 1) != sizeof(hdr) + caplen) {
error_report("network dump write error - stopping dump");
close(s->fd);
s->fd = -1;
}
return size;
}
static void dump_cleanup(DumpState *s)
{
close(s->fd);
s->fd = -1;
}
static int net_dump_state_init(DumpState *s, const char *filename,
int len, Error **errp)
{
struct pcap_file_hdr hdr;
struct tm tm;
int fd;
fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0644);
if (fd < 0) {
error_setg_errno(errp, errno, "net dump: can't open %s", filename);
return -1;
}
hdr.magic = PCAP_MAGIC;
hdr.version_major = 2;
hdr.version_minor = 4;
hdr.thiszone = 0;
hdr.sigfigs = 0;
hdr.snaplen = len;
hdr.linktype = 1;
if (write(fd, &hdr, sizeof(hdr)) < sizeof(hdr)) {
error_setg_errno(errp, errno, "net dump write error");
close(fd);
return -1;
}
s->fd = fd;
s->pcap_caplen = len;
qemu_get_timedate(&tm, 0);
s->start_ts = mktime(&tm);
return 0;
}
#define TYPE_FILTER_DUMP "filter-dump"
#define FILTER_DUMP(obj) \
OBJECT_CHECK(NetFilterDumpState, (obj), TYPE_FILTER_DUMP)
struct NetFilterDumpState {
NetFilterState nfs;
DumpState ds;
char *filename;
uint32_t maxlen;
};
typedef struct NetFilterDumpState NetFilterDumpState;
static ssize_t filter_dump_receive_iov(NetFilterState *nf, NetClientState *sndr,
unsigned flags, const struct iovec *iov,
int iovcnt, NetPacketSent *sent_cb)
{
NetFilterDumpState *nfds = FILTER_DUMP(nf);
dump_receive_iov(&nfds->ds, iov, iovcnt);
return 0;
}
static void filter_dump_cleanup(NetFilterState *nf)
{
NetFilterDumpState *nfds = FILTER_DUMP(nf);
dump_cleanup(&nfds->ds);
}
static void filter_dump_setup(NetFilterState *nf, Error **errp)
{
NetFilterDumpState *nfds = FILTER_DUMP(nf);
if (!nfds->filename) {
error_setg(errp, "dump filter needs 'file' property set!");
return;
}
net_dump_state_init(&nfds->ds, nfds->filename, nfds->maxlen, errp);
}
static void filter_dump_get_maxlen(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
NetFilterDumpState *nfds = FILTER_DUMP(obj);
uint32_t value = nfds->maxlen;
visit_type_uint32(v, name, &value, errp);
}
static void filter_dump_set_maxlen(Object *obj, Visitor *v, const char *name,
void *opaque, Error **errp)
{
NetFilterDumpState *nfds = FILTER_DUMP(obj);
uint32_t value;
if (!visit_type_uint32(v, name, &value, errp)) {
return;
}
if (value == 0) {
error_setg(errp, "Property '%s.%s' doesn't take value '%u'",
object_get_typename(obj), name, value);
return;
}
nfds->maxlen = value;
}
static char *file_dump_get_filename(Object *obj, Error **errp)
{
NetFilterDumpState *nfds = FILTER_DUMP(obj);
return g_strdup(nfds->filename);
}
static void file_dump_set_filename(Object *obj, const char *value, Error **errp)
{
NetFilterDumpState *nfds = FILTER_DUMP(obj);
g_free(nfds->filename);
nfds->filename = g_strdup(value);
}
static void filter_dump_instance_init(Object *obj)
{
NetFilterDumpState *nfds = FILTER_DUMP(obj);
nfds->maxlen = 65536;
object_property_add(obj, "maxlen", "uint32", filter_dump_get_maxlen,
filter_dump_set_maxlen, NULL, NULL);
object_property_add_str(obj, "file", file_dump_get_filename,
file_dump_set_filename);
}
static void filter_dump_instance_finalize(Object *obj)
{
NetFilterDumpState *nfds = FILTER_DUMP(obj);
g_free(nfds->filename);
}
static void filter_dump_class_init(ObjectClass *oc, void *data)
{
NetFilterClass *nfc = NETFILTER_CLASS(oc);
nfc->setup = filter_dump_setup;
nfc->cleanup = filter_dump_cleanup;
nfc->receive_iov = filter_dump_receive_iov;
}
static const TypeInfo filter_dump_info = {
.name = TYPE_FILTER_DUMP,
.parent = TYPE_NETFILTER,
.class_init = filter_dump_class_init,
.instance_init = filter_dump_instance_init,
.instance_finalize = filter_dump_instance_finalize,
.instance_size = sizeof(NetFilterDumpState),
};
static void filter_dump_register_types(void)
{
type_register_static(&filter_dump_info);
}
type_init(filter_dump_register_types);