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authorLennart Poettering <lennart@poettering.net>2014-10-30 01:13:11 +0100
committerLennart Poettering <lennart@poettering.net>2014-10-30 01:13:54 +0100
commit1f70b0876a9388f38422c12fa0c73761559d9425 (patch)
tree5833f283fd4adec22828f545f585033245856229 /src/libsystemd
parent1ab19cb167b32967556eefd8f6d3df0e3de7d67d (diff)
busctl: add new "capture" verb to record bus messages in libpcap compatible files, for dissection with wireshark
Diffstat (limited to 'src/libsystemd')
-rw-r--r--src/libsystemd/sd-bus/bus-dump.c96
-rw-r--r--src/libsystemd/sd-bus/bus-dump.h3
-rw-r--r--src/libsystemd/sd-bus/busctl.c68
3 files changed, 161 insertions, 6 deletions
diff --git a/src/libsystemd/sd-bus/bus-dump.c b/src/libsystemd/sd-bus/bus-dump.c
index 8b70b20e80..b536641eb9 100644
--- a/src/libsystemd/sd-bus/bus-dump.c
+++ b/src/libsystemd/sd-bus/bus-dump.c
@@ -23,6 +23,7 @@
#include "capability.h"
#include "strv.h"
#include "audit.h"
+#include "macro.h"
#include "bus-message.h"
#include "bus-internal.h"
@@ -424,3 +425,98 @@ int bus_creds_dump(sd_bus_creds *c, FILE *f) {
return 0;
}
+
+/*
+ * For details about the file format, see:
+ *
+ * http://wiki.wireshark.org/Development/LibpcapFileFormat
+ */
+
+typedef struct _packed_ pcap_hdr_s {
+ uint32_t magic_number; /* magic number */
+ uint16_t version_major; /* major version number */
+ uint16_t version_minor; /* minor version number */
+ int32_t thiszone; /* GMT to local correction */
+ uint32_t sigfigs; /* accuracy of timestamps */
+ uint32_t snaplen; /* max length of captured packets, in octets */
+ uint32_t network; /* data link type */
+} pcap_hdr_t ;
+
+typedef struct _packed_ pcaprec_hdr_s {
+ uint32_t ts_sec; /* timestamp seconds */
+ uint32_t ts_usec; /* timestamp microseconds */
+ uint32_t incl_len; /* number of octets of packet saved in file */
+ uint32_t orig_len; /* actual length of packet */
+} pcaprec_hdr_t;
+
+int bus_pcap_header(size_t snaplen, FILE *f) {
+
+ pcap_hdr_t hdr = {
+ .magic_number = 0xa1b2c3d4U,
+ .version_major = 2,
+ .version_minor = 4,
+ .thiszone = 0, /* UTC */
+ .sigfigs = 0,
+ .network = 231, /* D-Bus */
+ };
+
+ if (!f)
+ f = stdout;
+
+ assert(snaplen > 0);
+ assert((size_t) (uint32_t) snaplen == snaplen);
+
+ hdr.snaplen = (uint32_t) snaplen;
+
+ fwrite(&hdr, 1, sizeof(hdr), f);
+ fflush(f);
+
+ return 0;
+}
+
+int bus_message_pcap_frame(sd_bus_message *m, size_t snaplen, FILE *f) {
+ struct bus_body_part *part;
+ pcaprec_hdr_t hdr = {};
+ struct timeval tv;
+ unsigned i;
+ size_t w;
+
+ if (!f)
+ f = stdout;
+
+ assert(m);
+ assert(snaplen > 0);
+ assert((size_t) (uint32_t) snaplen == snaplen);
+
+ if (m->realtime != 0)
+ timeval_store(&tv, m->realtime);
+ else
+ assert_se(gettimeofday(&tv, NULL) >= 0);
+
+ hdr.ts_sec = tv.tv_sec;
+ hdr.ts_usec = tv.tv_usec;
+ hdr.orig_len = BUS_MESSAGE_SIZE(m);
+ hdr.incl_len = MIN(hdr.orig_len, snaplen);
+
+ /* write the pcap header */
+ fwrite(&hdr, 1, sizeof(hdr), f);
+
+ /* write the dbus header */
+ w = MIN(BUS_MESSAGE_BODY_BEGIN(m), snaplen);
+ fwrite(m->header, 1, w, f);
+ snaplen -= w;
+
+ /* write the dbus body */
+ MESSAGE_FOREACH_PART(part, i, m) {
+ if (snaplen <= 0)
+ break;
+
+ w = MIN(part->size, snaplen);
+ fwrite(part->data, 1, w, f);
+ snaplen -= w;
+ }
+
+ fflush(f);
+
+ return 0;
+}
diff --git a/src/libsystemd/sd-bus/bus-dump.h b/src/libsystemd/sd-bus/bus-dump.h
index bb1d25dc42..6af0ab066c 100644
--- a/src/libsystemd/sd-bus/bus-dump.h
+++ b/src/libsystemd/sd-bus/bus-dump.h
@@ -29,3 +29,6 @@
int bus_message_dump(sd_bus_message *m, FILE *f, bool with_header);
int bus_creds_dump(sd_bus_creds *c, FILE *f);
+
+int bus_pcap_header(size_t snaplen, FILE *f);
+int bus_message_pcap_frame(sd_bus_message *m, size_t snaplen, FILE *f);
diff --git a/src/libsystemd/sd-bus/busctl.c b/src/libsystemd/sd-bus/busctl.c
index fdc275ce46..faa0c60917 100644
--- a/src/libsystemd/sd-bus/busctl.c
+++ b/src/libsystemd/sd-bus/busctl.c
@@ -44,6 +44,7 @@ static char **arg_matches = NULL;
static BusTransport arg_transport = BUS_TRANSPORT_LOCAL;
static char *arg_host = NULL;
static bool arg_user = false;
+static size_t arg_snaplen = 4096;
static void pager_open_if_enabled(void) {
@@ -223,7 +224,15 @@ static int list_bus_names(sd_bus *bus, char **argv) {
return 0;
}
-static int monitor(sd_bus *bus, char *argv[]) {
+static int message_dump(sd_bus_message *m, FILE *f) {
+ return bus_message_dump(m, f, true);
+}
+
+static int message_pcap(sd_bus_message *m, FILE *f) {
+ return bus_message_pcap_frame(m, arg_snaplen, f);
+}
+
+static int monitor(sd_bus *bus, char *argv[], int (*dump)(sd_bus_message *m, FILE *f)) {
bool added_something = false;
char **i;
int r;
@@ -277,7 +286,7 @@ static int monitor(sd_bus *bus, char *argv[]) {
}
if (m) {
- bus_message_dump(m, stdout, true);
+ dump(m, stdout);
continue;
}
@@ -292,6 +301,28 @@ static int monitor(sd_bus *bus, char *argv[]) {
}
}
+static int capture(sd_bus *bus, char *argv[]) {
+ int r;
+
+ if (isatty(fileno(stdout)) > 0) {
+ log_error("Refusing to write message data to console, please redirect output to a file.");
+ return -EINVAL;
+ }
+
+ bus_pcap_header(arg_snaplen, stdout);
+
+ r = monitor(bus, argv, message_pcap);
+ if (r < 0)
+ return r;
+
+ if (ferror(stdout)) {
+ log_error("Couldn't write capture file.");
+ return -EIO;
+ }
+
+ return r;
+}
+
static int status(sd_bus *bus, char *argv[]) {
_cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
pid_t pid;
@@ -339,6 +370,7 @@ static int help(void) {
"Commands:\n"
" list List bus names\n"
" monitor [SERVICE...] Show bus traffic\n"
+ " capture [SERVICE...] Capture bus traffic as pcap\n"
" status NAME Show name status\n"
" help Show this help\n"
, program_invocation_short_name);
@@ -359,7 +391,8 @@ static int parse_argv(int argc, char *argv[]) {
ARG_SHOW_MACHINE,
ARG_UNIQUE,
ARG_ACQUIRED,
- ARG_ACTIVATABLE
+ ARG_ACTIVATABLE,
+ ARG_SIZE,
};
static const struct option options[] = {
@@ -377,10 +410,11 @@ static int parse_argv(int argc, char *argv[]) {
{ "match", required_argument, NULL, ARG_MATCH },
{ "host", required_argument, NULL, 'H' },
{ "machine", required_argument, NULL, 'M' },
+ { "size", required_argument, NULL, ARG_SIZE },
{},
};
- int c;
+ int c, r;
assert(argc >= 0);
assert(argv);
@@ -438,6 +472,24 @@ static int parse_argv(int argc, char *argv[]) {
return log_oom();
break;
+ case ARG_SIZE: {
+ off_t o;
+
+ r = parse_size(optarg, 0, &o);
+ if (r < 0) {
+ log_error("Failed to parse size: %s", optarg);
+ return r;
+ }
+
+ if ((off_t) (size_t) o != o) {
+ log_error("Size out of range.");
+ return -E2BIG;
+ }
+
+ arg_snaplen = (size_t) o;
+ break;
+ }
+
case 'H':
arg_transport = BUS_TRANSPORT_REMOTE;
arg_host = optarg;
@@ -469,7 +521,10 @@ static int busctl_main(sd_bus *bus, int argc, char *argv[]) {
return list_bus_names(bus, argv + optind);
if (streq(argv[optind], "monitor"))
- return monitor(bus, argv + optind);
+ return monitor(bus, argv + optind, message_dump);
+
+ if (streq(argv[optind], "capture"))
+ return capture(bus, argv + optind);
if (streq(argv[optind], "status"))
return status(bus, argv + optind);
@@ -498,7 +553,8 @@ int main(int argc, char *argv[]) {
goto finish;
}
- if (streq_ptr(argv[optind], "monitor")) {
+ if (streq_ptr(argv[optind], "monitor") ||
+ streq_ptr(argv[optind], "capture")) {
r = sd_bus_set_monitor(bus, true);
if (r < 0) {