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Flexible guestfs_vmchannel parameter for future appliances.

Browse Source 
This reimplements parts of commit da0a4f8d1f
in a different, but compatible way.

We pass guestfs_vmchannel=tcp:<ip>:<port> on the command line.  This
is intended to be used as follows (now and in future versions):

  tcp:10.0.2.4:6666    for guestfwd vmchannel
  tcp:10.0.2.2:<port>  for future "no vmchannel" implementation
  /dev/vcon4           for future virtio-console vmchannel*

It also accepts the old-style guestfs=10.0.2.4:6666 parameter which
is sent by older libraries, and turns this transparently into the
correct format above.

If no guestfs_vmchannel is passed, then this defaults to the guestfwd
vmchannel which older libraries would expect.

* Maybe this last one should be dev:/dev/vcon4 or file:/dev/vcon4, but
we don't need to decide that now.
This commit is contained in:
Richard Jones
2009-09-21 13:03:27 +01:00
parent 8b91ee5e2d
commit 8b217a87bf
2 changed files with 144 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

177
daemon/guestfsd.c
View File

@@ -40,7 +40,6 @@
#include "daemon.h"
static void usage (void);
static char *read_cmdline (void);
/* Also in guestfs.c */
@@ -65,18 +64,28 @@ static int print_arginfo (const struct printf_info *info, size_t n, int *argtype
const char *sysroot = "/sysroot"; /* No trailing slash. */
int sysroot_len = 8;
static void
usage (void)
{
fprintf (stderr,
"guestfsd [-f|--foreground] [-c|--channel vmchannel] [-v|--verbose]\n");
}
int
main (int argc, char *argv[])
{
static const char *options = "f?";
static const char *options = "fc:v?";
static const struct option long_options[] = {
{ "channel", required_argument, 0, 'c' },
{ "foreground", 0, 0, 'f' },
{ "help", 0, 0, '?' },
{ "verbose", 0, 0, 'v' },
{ 0, 0, 0, 0 }
};
int c;
int dont_fork = 0;
char *cmdline;
char *vmchannel = NULL;
#ifdef HAVE_REGISTER_PRINTF_SPECIFIER
/* http://udrepper.livejournal.com/20948.html */
@@ -96,10 +105,18 @@ main (int argc, char *argv[])
if (c == -1) break;
switch (c) {
case 'c':
vmchannel = optarg;
break;
case 'f':
dont_fork = 1;
break;
case 'v':
verbose = 1;
break;
case '?':
usage ();
exit (0);
@@ -118,7 +135,8 @@ main (int argc, char *argv[])
cmdline = read_cmdline ();
/* Set the verbose flag. */
verbose = cmdline && strstr (cmdline, "guestfs_verbose=1") != NULL;
verbose = verbose ||
(cmdline && strstr (cmdline, "guestfs_verbose=1") != NULL);
if (verbose)
printf ("verbose daemon enabled\n");
@@ -148,38 +166,129 @@ main (int argc, char *argv[])
/* We document that umask defaults to 022 (it should be this anyway). */
umask (022);
/* Resolve the hostname. */
struct addrinfo *res, *rr;
struct addrinfo hints;
int r;
memset (&hints, 0, sizeof hints);
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_ADDRCONFIG;
r = getaddrinfo (GUESTFWD_ADDR, GUESTFWD_PORT, &hints, &res);
if (r != 0) {
fprintf (stderr, "%s:%s: %s\n",
GUESTFWD_ADDR, GUESTFWD_PORT, gai_strerror (r));
/* Get the vmchannel string.
*
* Sources:
* --channel/-c option on the command line
* guestfs_vmchannel=... from the kernel command line
* guestfs=... from the kernel command line
* built-in default
*
* At the moment we expect this to contain "tcp:ip:port" but in
* future it might contain a device name, eg. "/dev/vcon4" for
* virtio-console vmchannel.
*/
if (vmchannel == NULL && cmdline) {
char *p;
size_t len;
p = strstr (cmdline, "guestfs_vmchannel=");
if (p) {
len = strcspn (p + 18, " \t\n");
vmchannel = strndup (p + 18, len);
if (!vmchannel) {
perror ("strndup");
exit (1);
}
}
/* Old libraries passed guestfs=host:port. Rewrite it as tcp:host:port. */
if (vmchannel == NULL) {
/* We will rewrite it part of the "guestfs=" string with
* "tcp:" hence p + 4 below. */
p = strstr (cmdline, "guestfs=");
if (p) {
len = strcspn (p + 4, " \t\n");
vmchannel = strndup (p + 4, len);
if (!vmchannel) {
perror ("strndup");
exit (1);
}
memcpy (vmchannel, "tcp:", 4);
}
}
}
/* Default vmchannel. */
if (vmchannel == NULL) {
vmchannel = strdup ("tcp:" GUESTFWD_ADDR ":" GUESTFWD_PORT);
if (!vmchannel) {
perror ("strdup");
exit (1);
}
}
if (verbose)
printf ("vmchannel: %s\n", vmchannel);
/* Connect to vmchannel. */
int sock = -1;
if (strncmp (vmchannel, "tcp:", 4) == 0) {
/* Resolve the hostname. */
struct addrinfo *res, *rr;
struct addrinfo hints;
int r;
char *host, *port;
host = vmchannel+4;
port = strchr (host, ':');
if (port) {
port[0] = '\0';
port++;
} else {
fprintf (stderr, "vmchannel: expecting \"tcp:<ip>:<port>\": %s\n",
vmchannel);
exit (1);
}
memset (&hints, 0, sizeof hints);
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_ADDRCONFIG;
r = getaddrinfo (host, port, &hints, &res);
if (r != 0) {
fprintf (stderr, "%s:%s: %s\n",
host, port, gai_strerror (r));
exit (1);
}
/* Connect to the given TCP socket. */
for (rr = res; rr != NULL; rr = rr->ai_next) {
sock = socket (rr->ai_family, rr->ai_socktype, rr->ai_protocol);
if (sock != -1) {
if (connect (sock, rr->ai_addr, rr->ai_addrlen) == 0)
break;
perror ("connect");
close (sock);
sock = -1;
}
}
freeaddrinfo (res);
} else {
fprintf (stderr,
"unknown vmchannel connection type: %s\n"
"expecting \"tcp:<ip>:<port>\"\n",
vmchannel);
exit (1);
}
/* Connect to the given TCP socket. */
int sock = -1;
for (rr = res; rr != NULL; rr = rr->ai_next) {
sock = socket (rr->ai_family, rr->ai_socktype, rr->ai_protocol);
if (sock != -1) {
if (connect (sock, rr->ai_addr, rr->ai_addrlen) == 0)
break;
perror ("connect");
close (sock);
sock = -1;
}
}
freeaddrinfo (res);
if (sock == -1) {
fprintf (stderr, "connection to %s:%s failed\n",
GUESTFWD_ADDR, GUESTFWD_PORT);
fprintf (stderr,
"\n"
"Failed to connect to any vmchannel implementation.\n"
"vmchannel: %s\n"
"\n"
"This is a fatal error and the appliance will now exit.\n"
"\n"
"Usually this error is caused by either QEMU or the appliance\n"
"kernel not supporting the vmchannel method that the\n"
"libguestfs library chose to use. Please run\n"
"'libguestfs-test-tool' and provide the complete, unedited\n"
"output to the libguestfs developers, either in a bug report\n"
"or on the libguestfs redhat com mailing list.\n"
"\n",
vmchannel);
exit (1);
}
@@ -323,12 +432,6 @@ xread (int sock, void *v_buf, size_t len)
return 0;
}
static void
usage (void)
{
fprintf (stderr, "guestfsd [-f]\n");
}
int
add_string (char ***argv, int *size, int *alloc, const char *str)
{

4
src/guestfs.c
View File

@@ -984,6 +984,7 @@ guestfs__launch (guestfs_h *g)
if (r == 0) { /* Child (qemu). */
char buf[256];
const char *vmchannel = NULL;
/* Set up the full command line. Do this in the subprocess so we
* don't need to worry about cleaning up.
@@ -1045,6 +1046,7 @@ guestfs__launch (guestfs_h *g)
}
add_cmdline (g, "-net");
add_cmdline (g, "nic,model=" NET_IF ",vlan=0");
vmchannel = "guestfs_vmchannel=tcp:" GUESTFWD_ADDR ":" GUESTFWD_PORT " ";
#define LINUX_CMDLINE \
"panic=1 " /* force kernel to panic if daemon exits */ \
@@ -1058,9 +1060,11 @@ guestfs__launch (guestfs_h *g)
snprintf (buf, sizeof buf,
LINUX_CMDLINE
"%s" /* (selinux) */
"%s" /* (vmchannel) */
"%s" /* (verbose) */
"%s", /* (append) */
g->selinux ? "selinux=1 enforcing=0 " : "selinux=0 ",
vmchannel ? vmchannel : "",
g->verbose ? "guestfs_verbose=1 " : "",
g->append ? g->append : "");