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net: truncate output file when using dump backend

PATCH Superseded Hervé Poussineau 3 participants 4 messages Nov 6, 2011 – Nov 7, 2011 Networking

v1 of 2 Superseded Latest is v2 →

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Hervé Poussineau

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#0 lore raw

PATCH 1/2 net: truncate output file when using dump backend

Signed-off-by Hervé Poussineau <[email protected]>
---
 net/dump.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
net/dump.c +1 -1
index 0d0cbb2..8132411 100644
@@ -106,7 +106,7 @@ static int net_dump_init(VLANState *vlan, const char *device,
     DumpState *s;
     int fd;
 
-    fd = open(filename, O_CREAT | O_WRONLY | O_BINARY, 0644);
+    fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0644);
     if (fd < 0) {
         error_report("-net dump: can't open %s", filename);
         return -1;
Signature · 1 line
1.7.6.3
author
#1 lore raw

PATCH 2/2 net: store correct timestamp in dump file

Signed-off-by Hervé Poussineau <[email protected]>
---
 net/dump.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
net/dump.c +6 -1
index 8132411..4b48d48 100644
@@ -30,6 +30,7 @@
 
 typedef struct DumpState {
     VLANClientState nc;
+    int64_t start_ts;
     int fd;
     int pcap_caplen;
 } DumpState;

@@ -70,7 +71,7 @@ static ssize_t dump_receive(VLANClientState *nc, const uint8_t *buf, size_t size
     ts = muldiv64(qemu_get_clock_ns(vm_clock), 1000000, get_ticks_per_sec());
     caplen = size > s->pcap_caplen ? s->pcap_caplen : size;
 
-    hdr.ts.tv_sec = ts / 1000000;
+    hdr.ts.tv_sec = ts / 1000000 + s->start_ts;
     hdr.ts.tv_usec = ts % 1000000;
     hdr.caplen = caplen;
     hdr.len = size;

@@ -104,6 +105,7 @@ static int net_dump_init(VLANState *vlan, const char *device,
     struct pcap_file_hdr hdr;
     VLANClientState *nc;
     DumpState *s;
+    struct tm tm;
     int fd;
 
     fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0644);

@@ -136,6 +138,9 @@ static int net_dump_init(VLANState *vlan, const char *device,
     s->fd = fd;
     s->pcap_caplen = len;
 
+    qemu_get_timedate(&tm, 0);
+    s->start_ts = mktime(&tm);
+
     return 0;
 }
Signature · 1 line
1.7.6.3
#2 lore raw

Re: [Qemu-devel] [PATCH 2/2] net: store correct timestamp in dump file

Quoted 18 lines · Hervé Poussineau
Signed-off-by Hervé Poussineau<[email protected]>
---
  net/dump.c |    7 ++++++-
  1 files changed, 6 insertions(+), 1 deletions(-)
net/dump.c +1 -0
index 8132411..4b48d48 100644
@@ -30,6 +30,7 @@
 
  typedef struct DumpState {
      VLANClientState nc;
+    int64_t start_ts;
      int fd;
      int pcap_caplen;
  } DumpState;

net/dump.c static ssize_t dump_receive(VLANClientState *nc, const uint8_t *buf, size_t size · line 71

Quoted 1 line
net/dump.c +0 -0
@@ -70,7 +71,7 @@ static ssize_t dump_receive(VLANClientState *nc, const uint8_t *buf, size_t size
      ts = muldiv64(qemu_get_clock_ns(vm_clock), 1000000, get_ticks_per_sec());

I agree that using host time as timestamp is more reasonable than the virtual clock because in most cases rtc for guest is based on host time not virtual clock.
I think we can simply use "host_clock" instead of "vm_clock" to achieve that. It will use the same time as host no matter what option is specified for guest's rtc. With your patch, the time stamp will keep the same as the choice of guest rtc, which is utc default.

- ts = muldiv64(qemu_get_clock_ns(vm_clock), 1000000,
get_ticks_per_sec());

+    ts = muldiv64(qemu_get_clock_ns(host_clock), 1000000, get_ticks_per_sec());
     caplen = size > s->pcap_caplen ? s->pcap_caplen : size;