| Message ID | 1473084701-23694-1-git-send-email-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 2016-09-05 at 16:11 +0200, Juergen Gross wrote: > diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c > @@ -1103,14 +1103,48 @@ int libxl__qmp_x_blockdev_change(libxl__gc > *gc, int domid, const char *parent, > return qmp_run_command(gc, domid, "x-blockdev-change", args, > NULL, NULL); > } > > -int libxl__qmp_hmp(libxl__gc *gc, int domid, const char > *command_line) > +static int hmp_callback(libxl__qmp_handler *qmp, > + const libxl__json_object *response, > + void *opaque) > +{ > + char **output = opaque; > + GC_INIT(qmp->ctx); > + int rc = 0; > + I'm probably being a bit picky, but libxl's CODING_STYLE says rc should not be initialized. > + if (!output) > + goto out; > + > + *output = NULL; > + > + if (libxl__json_object_is_string(response)) { > + *output = libxl__strdup(gc, > libxl__json_object_get_string(response)); > + goto out; > + } > + > + LOG(ERROR, "Response has unexpected format"); > + rc = ERROR_FAIL; > + > +out: > + return rc; > +} > + Also, aren't we missing calling GC_FREE on the out path? > +int libxl__qmp_hmp(libxl__gc *gc, int domid, const char > *command_line, > + char **output) > { > libxl__json_object *args = NULL; > > qmp_parameters_add_string(gc, &args, "command-line", > command_line); > > return qmp_run_command(gc, domid, "human-monitor-command", args, > - NULL, NULL); > + hmp_callback, output); > +} > + > +int libxl_qemu_monitor_command(libxl_ctx *ctx, uint32_t domid, > + const char *command_line, char > **output) > +{ > + GC_INIT(ctx); > + > + return libxl__qmp_hmp(gc, domid, command_line, output); > GC_FREE; again ? > } > > diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c > @@ -9536,6 +9536,33 @@ int main_psr_hwinfo(int argc, char **argv) > > #endif > > +int main_qemu_monitor_command(int argc, char **argv) > +{ > + int opt; > + uint32_t domid; > + char *cmd; > + char *output; > + int ret; > + > + SWITCH_FOREACH_OPT(opt, "", NULL, "qemu-monitor-command", 2) { > + /* No options */ > + } > + > + domid = find_domain(argv[optind]); > + cmd = argv[optind + 1]; > + > + if (argc - optind > 2) { > + fprintf(stderr, "Invalid arguments.\n"); > + return 1; > + } > + > + ret = libxl_qemu_monitor_command(ctx, domid, cmd, &output); > + if (!ret && output) > + printf("%s\n", output); > + > + return ret; > Things are not fully consistent yet, but there's an ongoing effort for having xl terminate with either EXIT_SUCCESS or EXIT_FAILURE. Can you use them when exit()-ing or, like in this case, returning from a main_foo() function? Regards, Dario
On 06/09/16 10:31, Dario Faggioli wrote: > On Mon, 2016-09-05 at 16:11 +0200, Juergen Gross wrote: >> diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c >> @@ -1103,14 +1103,48 @@ int libxl__qmp_x_blockdev_change(libxl__gc >> *gc, int domid, const char *parent, >> return qmp_run_command(gc, domid, "x-blockdev-change", args, >> NULL, NULL); >> } >> >> -int libxl__qmp_hmp(libxl__gc *gc, int domid, const char >> *command_line) >> +static int hmp_callback(libxl__qmp_handler *qmp, >> + const libxl__json_object *response, >> + void *opaque) >> +{ >> + char **output = opaque; >> + GC_INIT(qmp->ctx); >> + int rc = 0; >> + > I'm probably being a bit picky, but libxl's CODING_STYLE says rc should > not be initialized. Okay. > >> + if (!output) >> + goto out; >> + >> + *output = NULL; >> + >> + if (libxl__json_object_is_string(response)) { >> + *output = libxl__strdup(gc, >> libxl__json_object_get_string(response)); >> + goto out; >> + } >> + >> + LOG(ERROR, "Response has unexpected format"); >> + rc = ERROR_FAIL; >> + >> +out: >> + return rc; >> +} >> + > Also, aren't we missing calling GC_FREE on the out path? Yes. And libxl__strdup should use NOGC. > >> +int libxl__qmp_hmp(libxl__gc *gc, int domid, const char >> *command_line, >> + char **output) >> { >> libxl__json_object *args = NULL; >> >> qmp_parameters_add_string(gc, &args, "command-line", >> command_line); >> >> return qmp_run_command(gc, domid, "human-monitor-command", args, >> - NULL, NULL); >> + hmp_callback, output); >> +} >> + >> +int libxl_qemu_monitor_command(libxl_ctx *ctx, uint32_t domid, >> + const char *command_line, char >> **output) >> +{ >> + GC_INIT(ctx); >> + >> + return libxl__qmp_hmp(gc, domid, command_line, output); >> > GC_FREE; again ? Yep. > >> } >> > >> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c >> @@ -9536,6 +9536,33 @@ int main_psr_hwinfo(int argc, char **argv) >> >> #endif >> >> +int main_qemu_monitor_command(int argc, char **argv) >> +{ >> + int opt; >> + uint32_t domid; >> + char *cmd; >> + char *output; >> + int ret; >> + >> + SWITCH_FOREACH_OPT(opt, "", NULL, "qemu-monitor-command", 2) { >> + /* No options */ >> + } >> + >> + domid = find_domain(argv[optind]); >> + cmd = argv[optind + 1]; >> + >> + if (argc - optind > 2) { >> + fprintf(stderr, "Invalid arguments.\n"); >> + return 1; >> + } >> + >> + ret = libxl_qemu_monitor_command(ctx, domid, cmd, &output); >> + if (!ret && output) >> + printf("%s\n", output); >> + >> + return ret; >> > Things are not fully consistent yet, but there's an ongoing effort for > having xl terminate with either EXIT_SUCCESS or EXIT_FAILURE. Can you > use them when exit()-ing or, like in this case, returning from a > main_foo() function? Sure. Thanks, Juergen
diff --git a/docs/man/xl.pod.1.in b/docs/man/xl.pod.1.in index 1adf322..a2be541 100644 --- a/docs/man/xl.pod.1.in +++ b/docs/man/xl.pod.1.in @@ -1516,6 +1516,42 @@ List pass-through usb devices for a domain. =back +=head1 DEVICE-MODEL CONTROL + +=over 4 + +=item B<qemu-monitor-command> I<domain-id> I<command> + +Issue a monitor command to the device model of the domain specified by +I<domain-id>. I<command> can be any valid command qemu understands. This +can be e.g. used to add non-standard devices or devices with non-standard +parameters to a domain. The output of the command is printed to stdout. + +B<Warning:> This qemu monitor access is provided for convenience when +debugging, troubleshooting, and experimenting. Its use is not +supported by the Xen Project. + +Specifically, not all information printed by the qemu monitor will +necessarily be accurate or complete, because in a Xen system qemu +does not have a complete view of the guest. + +Furthermore, modifying the guest's setup via the qemu monitor may +conflict with the Xen toolstack's assumptions. Resulting problems +may include, but are not limited to: guest crashes; toolstack error +messages; inability to migrate the guest; and security +vulnerabilities which are not covered by the Xen Project security +response policy. + +B<EXAMPLE> + +Obtain information of USB devices connected as such via the device model +(only!) to a domain: + + xl qemu-monitor-command vm1 'info usb' + Device 0.2, Port 5, Speed 480 Mb/s, Product Mass Storage + +=back + =head1 TMEM =over 4 diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h index e4c25c4..7cfa540 100644 --- a/tools/libxl/libxl.h +++ b/tools/libxl/libxl.h @@ -275,6 +275,12 @@ #define LIBXL_HAVE_BUILD_ID 1 /* + * LIBXL_HAVE_QEMU_MONITOR_COMMAND indiactes the availability of the + * libxl_qemu_monitor_command() function. + */ +#define LIBXL_HAVE_QEMU_MONITOR_COMMAND 1 + +/* * libxl ABI compatibility * * The only guarantee which libxl makes regarding ABI compatibility @@ -2152,6 +2158,14 @@ void libxl_psr_cat_info_list_free(libxl_psr_cat_info *list, int nr); int libxl_fd_set_cloexec(libxl_ctx *ctx, int fd, int cloexec); int libxl_fd_set_nonblock(libxl_ctx *ctx, int fd, int nonblock); +/* + * Issue a qmp monitor command to the device model of the specified domain. + * The function returns the output of the command in a new allocated buffer + * via output. + */ +int libxl_qemu_monitor_command(libxl_ctx *ctx, uint32_t domid, + const char *command_line, char **output); + #include <libxl_event.h> #endif /* LIBXL_H */ diff --git a/tools/libxl/libxl_colo_qdisk.c b/tools/libxl/libxl_colo_qdisk.c index c23b81b..d271d1f 100644 --- a/tools/libxl/libxl_colo_qdisk.c +++ b/tools/libxl/libxl_colo_qdisk.c @@ -173,7 +173,7 @@ static void colo_qdisk_save_preresume(libxl__egc *egc, "file.driver=nbd,file.host=%s,file.port=%d," "file.export=%s,node-name=%s,if=none", host, port, export_name, node); - ret = libxl__qmp_hmp(gc, domid, cmd); + ret = libxl__qmp_hmp(gc, domid, cmd, NULL); if (ret) rc = ERROR_FAIL; diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h index ce8e17a..9f534c4 100644 --- a/tools/libxl/libxl_internal.h +++ b/tools/libxl/libxl_internal.h @@ -1818,7 +1818,8 @@ _hidden int libxl__qmp_x_blockdev_change(libxl__gc *gc, int domid, const char *parant, const char *child, const char *node); /* run a hmp command in qmp mode */ -_hidden int libxl__qmp_hmp(libxl__gc *gc, int domid, const char *command_line); +_hidden int libxl__qmp_hmp(libxl__gc *gc, int domid, const char *command_line, + char **out); /* close and free the QMP handler */ _hidden void libxl__qmp_close(libxl__qmp_handler *qmp); /* remove the socket file, if the file has already been removed, diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c index 63c49c5..33883b8 100644 --- a/tools/libxl/libxl_qmp.c +++ b/tools/libxl/libxl_qmp.c @@ -1103,14 +1103,48 @@ int libxl__qmp_x_blockdev_change(libxl__gc *gc, int domid, const char *parent, return qmp_run_command(gc, domid, "x-blockdev-change", args, NULL, NULL); } -int libxl__qmp_hmp(libxl__gc *gc, int domid, const char *command_line) +static int hmp_callback(libxl__qmp_handler *qmp, + const libxl__json_object *response, + void *opaque) +{ + char **output = opaque; + GC_INIT(qmp->ctx); + int rc = 0; + + if (!output) + goto out; + + *output = NULL; + + if (libxl__json_object_is_string(response)) { + *output = libxl__strdup(gc, libxl__json_object_get_string(response)); + goto out; + } + + LOG(ERROR, "Response has unexpected format"); + rc = ERROR_FAIL; + +out: + return rc; +} + +int libxl__qmp_hmp(libxl__gc *gc, int domid, const char *command_line, + char **output) { libxl__json_object *args = NULL; qmp_parameters_add_string(gc, &args, "command-line", command_line); return qmp_run_command(gc, domid, "human-monitor-command", args, - NULL, NULL); + hmp_callback, output); +} + +int libxl_qemu_monitor_command(libxl_ctx *ctx, uint32_t domid, + const char *command_line, char **output) +{ + GC_INIT(ctx); + + return libxl__qmp_hmp(gc, domid, command_line, output); } int libxl__qmp_initializations(libxl__gc *gc, uint32_t domid, diff --git a/tools/libxl/xl.h b/tools/libxl/xl.h index e601ca1..0a8c813 100644 --- a/tools/libxl/xl.h +++ b/tools/libxl/xl.h @@ -133,6 +133,7 @@ int main_psr_cmt_show(int argc, char **argv); int main_psr_cat_cbm_set(int argc, char **argv); int main_psr_cat_show(int argc, char **argv); #endif +int main_qemu_monitor_command(int argc, char **argv); void help(const char *command); diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c index 7540fb1..ad2cba5 100644 --- a/tools/libxl/xl_cmdimpl.c +++ b/tools/libxl/xl_cmdimpl.c @@ -9536,6 +9536,33 @@ int main_psr_hwinfo(int argc, char **argv) #endif +int main_qemu_monitor_command(int argc, char **argv) +{ + int opt; + uint32_t domid; + char *cmd; + char *output; + int ret; + + SWITCH_FOREACH_OPT(opt, "", NULL, "qemu-monitor-command", 2) { + /* No options */ + } + + domid = find_domain(argv[optind]); + cmd = argv[optind + 1]; + + if (argc - optind > 2) { + fprintf(stderr, "Invalid arguments.\n"); + return 1; + } + + ret = libxl_qemu_monitor_command(ctx, domid, cmd, &output); + if (!ret && output) + printf("%s\n", output); + + return ret; +} + /* * Local variables: * mode: C diff --git a/tools/libxl/xl_cmdtable.c b/tools/libxl/xl_cmdtable.c index 85c1e0f..78786fe 100644 --- a/tools/libxl/xl_cmdtable.c +++ b/tools/libxl/xl_cmdtable.c @@ -584,6 +584,11 @@ struct cmd_spec cmd_table[] = { "List information about all USB controllers and devices for a domain", "<Domain>", }, + { "qemu-monitor-command", + &main_qemu_monitor_command, 0, 1, + "Issue a qemu monitor command to the device model of a domain", + "<Domain> <Command>", + }, }; int cmdtable_len = sizeof(cmd_table)/sizeof(struct cmd_spec);
Add a new xl command "qemu-monitor-command" to issue arbitrary commands to a domain's device model. Syntax is: xl qemu-monitor-command <domain> <command> The command is issued via qmp human-monitor-command command. Any information returned by the command is printed to stdout. Signed-off-by: Juergen Gross <jgross@suse.com> --- docs/man/xl.pod.1.in | 36 ++++++++++++++++++++++++++++++++++++ tools/libxl/libxl.h | 14 ++++++++++++++ tools/libxl/libxl_colo_qdisk.c | 2 +- tools/libxl/libxl_internal.h | 3 ++- tools/libxl/libxl_qmp.c | 38 ++++++++++++++++++++++++++++++++++++-- tools/libxl/xl.h | 1 + tools/libxl/xl_cmdimpl.c | 27 +++++++++++++++++++++++++++ tools/libxl/xl_cmdtable.c | 5 +++++ 8 files changed, 122 insertions(+), 4 deletions(-)