conf: Make the argument to --pcap option mandatory

The --pcap or -p option can be used with or without an argument.  If given,
the argument gives the name of the file to save a packet trace to.  If
omitted, we generate a default name in /tmp.

Generating the default name isn't particularly useful though, since making
a suitable name can easily be done by the caller.  Remove this feature.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
David Gibson 2022-08-26 14:58:32 +10:00 committed by Stefano Brivio
parent 63d1390229
commit bf95322fc1
3 changed files with 3 additions and 53 deletions

18
conf.c
View file

@ -737,14 +737,7 @@ static void usage(const char *name)
UNIX_SOCK_PATH, 1); UNIX_SOCK_PATH, 1);
} }
info( " -p, --pcap [FILE] Log tap-facing traffic to pcap file"); info( " -p, --pcap FILE Log tap-facing traffic to pcap file");
info( " if FILE is not given, log to:");
if (strstr(name, "pasta"))
info(" /tmp/pasta_ISO8601-TIMESTAMP_PID.pcap");
else
info(" /tmp/passt_ISO8601-TIMESTAMP_PID.pcap");
info( " -P, --pid FILE Write own PID to the given file"); info( " -P, --pid FILE Write own PID to the given file");
info( " -m, --mtu MTU Assign MTU via DHCP/NDP"); info( " -m, --mtu MTU Assign MTU via DHCP/NDP");
info( " a zero value disables assignment"); info( " a zero value disables assignment");
@ -1021,7 +1014,7 @@ void conf(struct ctx *c, int argc, char **argv)
{"help", no_argument, NULL, 'h' }, {"help", no_argument, NULL, 'h' },
{"socket", required_argument, NULL, 's' }, {"socket", required_argument, NULL, 's' },
{"ns-ifname", required_argument, NULL, 'I' }, {"ns-ifname", required_argument, NULL, 'I' },
{"pcap", optional_argument, NULL, 'p' }, {"pcap", required_argument, NULL, 'p' },
{"pid", required_argument, NULL, 'P' }, {"pid", required_argument, NULL, 'P' },
{"mtu", required_argument, NULL, 'm' }, {"mtu", required_argument, NULL, 'm' },
{"address", required_argument, NULL, 'a' }, {"address", required_argument, NULL, 'a' },
@ -1084,7 +1077,7 @@ void conf(struct ctx *c, int argc, char **argv)
name = getopt_long(argc, argv, optstring, options, NULL); name = getopt_long(argc, argv, optstring, options, NULL);
if ((name == 'p' || name == 'D' || name == 'S') && !optarg && if ((name == 'D' || name == 'S') && !optarg &&
optind < argc && *argv[optind] && *argv[optind] != '-') { optind < argc && *argv[optind] && *argv[optind] != '-') {
if (c->mode == MODE_PASTA) { if (c->mode == MODE_PASTA) {
if (conf_ns_opt(c, nsdir, userns, argv[optind])) if (conf_ns_opt(c, nsdir, userns, argv[optind]))
@ -1289,11 +1282,6 @@ void conf(struct ctx *c, int argc, char **argv)
usage(argv[0]); usage(argv[0]);
} }
if (!optarg) {
*c->pcap = 1;
break;
}
ret = snprintf(c->pcap, sizeof(c->pcap), "%s", optarg); ret = snprintf(c->pcap, sizeof(c->pcap), "%s", optarg);
if (ret <= 0 || ret >= (int)sizeof(c->pcap)) { if (ret <= 0 || ret >= (int)sizeof(c->pcap)) {
err("Invalid pcap path: %s", optarg); err("Invalid pcap path: %s", optarg);

10
passt.1
View file

@ -111,16 +111,6 @@ Display a help message and exit.
Capture tap-facing (that is, guest-side or namespace-side) network packets to Capture tap-facing (that is, guest-side or namespace-side) network packets to
\fIfile\fR in \fBpcap\fR format. \fIfile\fR in \fBpcap\fR format.
If \fIfile\fR is not given, capture packets to
\fB/tmp/passt_\fIISO8601-timestamp\fR_\fIPID\fB.pcap\fR
in \fBpasst\fR mode and to
\fB/tmp/pasta_\fIISO8601-timestamp\fR_\fIPID\fB.pcap\fR
in \fBpasta\fR mode, where \fIPID\fR is the ID of the running process.
.TP .TP
.BR \-P ", " \-\-pid " " \fIfile .BR \-P ", " \-\-pid " " \fIfile
Write own PID to \fIfile\fR once initialisation is done, before forking to Write own PID to \fIfile\fR once initialisation is done, before forking to

28
pcap.c
View file

@ -31,11 +31,6 @@
#include "util.h" #include "util.h"
#include "passt.h" #include "passt.h"
#define PCAP_PREFIX "/tmp/passt_"
#define PCAP_PREFIX_PASTA "/tmp/pasta_"
#define PCAP_ISO8601_FORMAT "%FT%H:%M:%SZ"
#define PCAP_ISO8601_STR "YYYY-MM-ddTHH:mm:ssZ"
#define PCAP_VERSION_MINOR 4 #define PCAP_VERSION_MINOR 4
static int pcap_fd = -1; static int pcap_fd = -1;
@ -171,7 +166,6 @@ fail:
void pcap_init(struct ctx *c) void pcap_init(struct ctx *c)
{ {
int flags = O_WRONLY | O_CREAT | O_TRUNC; int flags = O_WRONLY | O_CREAT | O_TRUNC;
struct timeval tv;
if (pcap_fd != -1) if (pcap_fd != -1)
return; return;
@ -179,28 +173,6 @@ void pcap_init(struct ctx *c)
if (!*c->pcap) if (!*c->pcap)
return; return;
if (*c->pcap == 1) {
char name[] = PCAP_PREFIX PCAP_ISO8601_STR STR(UINT_MAX)
".pcap";
struct tm *tm;
if (c->mode == MODE_PASTA)
memcpy(name, PCAP_PREFIX_PASTA,
sizeof(PCAP_PREFIX_PASTA));
gettimeofday(&tv, NULL);
tm = localtime(&tv.tv_sec);
strftime(name + strlen(PCAP_PREFIX),
sizeof(PCAP_ISO8601_STR) - 1, PCAP_ISO8601_FORMAT, tm);
snprintf(name + strlen(PCAP_PREFIX) + strlen(PCAP_ISO8601_STR),
sizeof(name) - strlen(PCAP_PREFIX) -
strlen(PCAP_ISO8601_STR),
"_%i.pcap", getpid());
strncpy(c->pcap, name, PATH_MAX);
}
flags |= c->foreground ? O_CLOEXEC : 0; flags |= c->foreground ? O_CLOEXEC : 0;
pcap_fd = open(c->pcap, flags, S_IRUSR | S_IWUSR); pcap_fd = open(c->pcap, flags, S_IRUSR | S_IWUSR);
if (pcap_fd == -1) { if (pcap_fd == -1) {