xref: /openbmc/qemu/qga/commands.c (revision 784155cd)
1 /*
2  * QEMU Guest Agent common/cross-platform command implementations
3  *
4  * Copyright IBM Corp. 2012
5  *
6  * Authors:
7  *  Michael Roth      <mdroth@linux.vnet.ibm.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
10  * See the COPYING file in the top-level directory.
11  */
12 
13 #include "qemu/osdep.h"
14 #include "qemu/units.h"
15 #include "guest-agent-core.h"
16 #include "qga-qapi-commands.h"
17 #include "qapi/error.h"
18 #include "qapi/qmp/qerror.h"
19 #include "qemu/base64.h"
20 #include "qemu/cutils.h"
21 #include "commands-common.h"
22 
23 /* Maximum captured guest-exec out_data/err_data - 16MB */
24 #define GUEST_EXEC_MAX_OUTPUT (16 * 1024 * 1024)
25 /* Allocation and I/O buffer for reading guest-exec out_data/err_data - 4KB */
26 #define GUEST_EXEC_IO_SIZE (4 * 1024)
27 /*
28  * Maximum file size to read - 48MB
29  *
30  * (48MB + Base64 3:4 overhead = JSON parser 64 MB limit)
31  */
32 #define GUEST_FILE_READ_COUNT_MAX (48 * MiB)
33 
34 /* Note: in some situations, like with the fsfreeze, logging may be
35  * temporarily disabled. if it is necessary that a command be able
36  * to log for accounting purposes, check ga_logging_enabled() beforehand.
37  */
38 void slog(const gchar *fmt, ...)
39 {
40     va_list ap;
41 
42     va_start(ap, fmt);
43     g_logv("syslog", G_LOG_LEVEL_INFO, fmt, ap);
44     va_end(ap);
45 }
46 
47 int64_t qmp_guest_sync_delimited(int64_t id, Error **errp)
48 {
49     ga_set_response_delimited(ga_state);
50     return id;
51 }
52 
53 int64_t qmp_guest_sync(int64_t id, Error **errp)
54 {
55     return id;
56 }
57 
58 void qmp_guest_ping(Error **errp)
59 {
60     slog("guest-ping called");
61 }
62 
63 static void qmp_command_info(const QmpCommand *cmd, void *opaque)
64 {
65     GuestAgentInfo *info = opaque;
66     GuestAgentCommandInfo *cmd_info;
67 
68     cmd_info = g_new0(GuestAgentCommandInfo, 1);
69     cmd_info->name = g_strdup(qmp_command_name(cmd));
70     cmd_info->enabled = qmp_command_is_enabled(cmd);
71     cmd_info->success_response = qmp_has_success_response(cmd);
72 
73     QAPI_LIST_PREPEND(info->supported_commands, cmd_info);
74 }
75 
76 struct GuestAgentInfo *qmp_guest_info(Error **errp)
77 {
78     GuestAgentInfo *info = g_new0(GuestAgentInfo, 1);
79 
80     info->version = g_strdup(QEMU_VERSION);
81     qmp_for_each_command(&ga_commands, qmp_command_info, info);
82     return info;
83 }
84 
85 struct GuestExecIOData {
86     guchar *data;
87     gsize size;
88     gsize length;
89     bool closed;
90     bool truncated;
91     const char *name;
92 };
93 typedef struct GuestExecIOData GuestExecIOData;
94 
95 struct GuestExecInfo {
96     GPid pid;
97     int64_t pid_numeric;
98     gint status;
99     bool has_output;
100     bool finished;
101     GuestExecIOData in;
102     GuestExecIOData out;
103     GuestExecIOData err;
104     QTAILQ_ENTRY(GuestExecInfo) next;
105 };
106 typedef struct GuestExecInfo GuestExecInfo;
107 
108 static struct {
109     QTAILQ_HEAD(, GuestExecInfo) processes;
110 } guest_exec_state = {
111     .processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes),
112 };
113 
114 static int64_t gpid_to_int64(GPid pid)
115 {
116 #ifdef G_OS_WIN32
117     return GetProcessId(pid);
118 #else
119     return (int64_t)pid;
120 #endif
121 }
122 
123 static GuestExecInfo *guest_exec_info_add(GPid pid)
124 {
125     GuestExecInfo *gei;
126 
127     gei = g_new0(GuestExecInfo, 1);
128     gei->pid = pid;
129     gei->pid_numeric = gpid_to_int64(pid);
130     QTAILQ_INSERT_TAIL(&guest_exec_state.processes, gei, next);
131 
132     return gei;
133 }
134 
135 static GuestExecInfo *guest_exec_info_find(int64_t pid_numeric)
136 {
137     GuestExecInfo *gei;
138 
139     QTAILQ_FOREACH(gei, &guest_exec_state.processes, next) {
140         if (gei->pid_numeric == pid_numeric) {
141             return gei;
142         }
143     }
144 
145     return NULL;
146 }
147 
148 GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **errp)
149 {
150     GuestExecInfo *gei;
151     GuestExecStatus *ges;
152 
153     slog("guest-exec-status called, pid: %u", (uint32_t)pid);
154 
155     gei = guest_exec_info_find(pid);
156     if (gei == NULL) {
157         error_setg(errp, QERR_INVALID_PARAMETER, "pid");
158         return NULL;
159     }
160 
161     ges = g_new0(GuestExecStatus, 1);
162 
163     bool finished = gei->finished;
164 
165     /* need to wait till output channels are closed
166      * to be sure we captured all output at this point */
167     if (gei->has_output) {
168         finished &= gei->out.closed && gei->err.closed;
169     }
170 
171     ges->exited = finished;
172     if (finished) {
173         /* Glib has no portable way to parse exit status.
174          * On UNIX, we can get either exit code from normal termination
175          * or signal number.
176          * On Windows, it is either the same exit code or the exception
177          * value for an unhandled exception that caused the process
178          * to terminate.
179          * See MSDN for GetExitCodeProcess() and ntstatus.h for possible
180          * well-known codes, e.g. C0000005 ACCESS_DENIED - analog of SIGSEGV
181          * References:
182          *   https://msdn.microsoft.com/en-us/library/windows/desktop/ms683189(v=vs.85).aspx
183          *   https://msdn.microsoft.com/en-us/library/aa260331(v=vs.60).aspx
184          */
185 #ifdef G_OS_WIN32
186         /* Additionally WIN32 does not provide any additional information
187          * on whether the child exited or terminated via signal.
188          * We use this simple range check to distinguish application exit code
189          * (usually value less then 256) and unhandled exception code with
190          * ntstatus (always value greater then 0xC0000005). */
191         if ((uint32_t)gei->status < 0xC0000000U) {
192             ges->has_exitcode = true;
193             ges->exitcode = gei->status;
194         } else {
195             ges->has_signal = true;
196             ges->signal = gei->status;
197         }
198 #else
199         if (WIFEXITED(gei->status)) {
200             ges->has_exitcode = true;
201             ges->exitcode = WEXITSTATUS(gei->status);
202         } else if (WIFSIGNALED(gei->status)) {
203             ges->has_signal = true;
204             ges->signal = WTERMSIG(gei->status);
205         }
206 #endif
207         if (gei->out.length > 0) {
208             ges->out_data = g_base64_encode(gei->out.data, gei->out.length);
209             g_free(gei->out.data);
210             ges->has_out_truncated = gei->out.truncated;
211         }
212 
213         if (gei->err.length > 0) {
214             ges->err_data = g_base64_encode(gei->err.data, gei->err.length);
215             g_free(gei->err.data);
216             ges->has_err_truncated = gei->err.truncated;
217         }
218 
219         QTAILQ_REMOVE(&guest_exec_state.processes, gei, next);
220         g_free(gei);
221     }
222 
223     return ges;
224 }
225 
226 /* Get environment variables or arguments array for execve(). */
227 static char **guest_exec_get_args(const strList *entry, bool log)
228 {
229     const strList *it;
230     int count = 1, i = 0;  /* reserve for NULL terminator */
231     char **args;
232     char *str; /* for logging array of arguments */
233     size_t str_size = 1;
234 
235     for (it = entry; it != NULL; it = it->next) {
236         count++;
237         str_size += 1 + strlen(it->value);
238     }
239 
240     str = g_malloc(str_size);
241     *str = 0;
242     args = g_new(char *, count);
243     for (it = entry; it != NULL; it = it->next) {
244         args[i++] = it->value;
245         pstrcat(str, str_size, it->value);
246         if (it->next) {
247             pstrcat(str, str_size, " ");
248         }
249     }
250     args[i] = NULL;
251 
252     if (log) {
253         slog("guest-exec called: \"%s\"", str);
254     }
255     g_free(str);
256 
257     return args;
258 }
259 
260 static void guest_exec_child_watch(GPid pid, gint status, gpointer data)
261 {
262     GuestExecInfo *gei = (GuestExecInfo *)data;
263 
264     g_debug("guest_exec_child_watch called, pid: %d, status: %u",
265             (int32_t)gpid_to_int64(pid), (uint32_t)status);
266 
267     gei->status = status;
268     gei->finished = true;
269 
270     g_spawn_close_pid(pid);
271 }
272 
273 static void guest_exec_task_setup(gpointer data)
274 {
275 #if !defined(G_OS_WIN32)
276     bool has_merge = *(bool *)data;
277     struct sigaction sigact;
278 
279     if (has_merge) {
280         /*
281          * FIXME: When `GLIB_VERSION_MIN_REQUIRED` is bumped to 2.58+, use
282          * g_spawn_async_with_fds() to be portable on windows. The current
283          * logic does not work on windows b/c `GSpawnChildSetupFunc` is run
284          * inside the parent, not the child.
285          */
286         if (dup2(STDOUT_FILENO, STDERR_FILENO) != 0) {
287             slog("dup2() failed to merge stderr into stdout: %s",
288                  strerror(errno));
289         }
290     }
291 
292     /* Reset ignored signals back to default. */
293     memset(&sigact, 0, sizeof(struct sigaction));
294     sigact.sa_handler = SIG_DFL;
295 
296     if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
297         slog("sigaction() failed to reset child process's SIGPIPE: %s",
298              strerror(errno));
299     }
300 #endif
301 }
302 
303 static gboolean guest_exec_input_watch(GIOChannel *ch,
304         GIOCondition cond, gpointer p_)
305 {
306     GuestExecIOData *p = (GuestExecIOData *)p_;
307     gsize bytes_written = 0;
308     GIOStatus status;
309     GError *gerr = NULL;
310 
311     /* nothing left to write */
312     if (p->size == p->length) {
313         goto done;
314     }
315 
316     status = g_io_channel_write_chars(ch, (gchar *)p->data + p->length,
317             p->size - p->length, &bytes_written, &gerr);
318 
319     /* can be not 0 even if not G_IO_STATUS_NORMAL */
320     if (bytes_written != 0) {
321         p->length += bytes_written;
322     }
323 
324     /* continue write, our callback will be called again */
325     if (status == G_IO_STATUS_NORMAL || status == G_IO_STATUS_AGAIN) {
326         return true;
327     }
328 
329     if (gerr) {
330         g_warning("qga: i/o error writing to input_data channel: %s",
331                 gerr->message);
332         g_error_free(gerr);
333     }
334 
335 done:
336     g_io_channel_shutdown(ch, true, NULL);
337     g_io_channel_unref(ch);
338     p->closed = true;
339     g_free(p->data);
340 
341     return false;
342 }
343 
344 static gboolean guest_exec_output_watch(GIOChannel *ch,
345         GIOCondition cond, gpointer p_)
346 {
347     GuestExecIOData *p = (GuestExecIOData *)p_;
348     gsize bytes_read;
349     GIOStatus gstatus;
350 
351     if (cond == G_IO_HUP || cond == G_IO_ERR) {
352         goto close;
353     }
354 
355     if (p->size == p->length) {
356         gpointer t = NULL;
357         if (!p->truncated && p->size < GUEST_EXEC_MAX_OUTPUT) {
358             t = g_try_realloc(p->data, p->size + GUEST_EXEC_IO_SIZE);
359         }
360         if (t == NULL) {
361             /* ignore truncated output */
362             gchar buf[GUEST_EXEC_IO_SIZE];
363 
364             p->truncated = true;
365             gstatus = g_io_channel_read_chars(ch, buf, sizeof(buf),
366                                               &bytes_read, NULL);
367             if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
368                 goto close;
369             }
370 
371             return true;
372         }
373         p->size += GUEST_EXEC_IO_SIZE;
374         p->data = t;
375     }
376 
377     /* Calling read API once.
378      * On next available data our callback will be called again */
379     gstatus = g_io_channel_read_chars(ch, (gchar *)p->data + p->length,
380             p->size - p->length, &bytes_read, NULL);
381     if (gstatus == G_IO_STATUS_EOF || gstatus == G_IO_STATUS_ERROR) {
382         goto close;
383     }
384 
385     p->length += bytes_read;
386 
387     return true;
388 
389 close:
390     g_io_channel_shutdown(ch, true, NULL);
391     g_io_channel_unref(ch);
392     p->closed = true;
393     return false;
394 }
395 
396 static GuestExecCaptureOutputMode ga_parse_capture_output(
397         GuestExecCaptureOutput *capture_output)
398 {
399     if (!capture_output)
400         return GUEST_EXEC_CAPTURE_OUTPUT_MODE_NONE;
401     else if (capture_output->type == QTYPE_QBOOL)
402         return capture_output->u.flag ? GUEST_EXEC_CAPTURE_OUTPUT_MODE_SEPARATED
403                                       : GUEST_EXEC_CAPTURE_OUTPUT_MODE_NONE;
404     else
405         return capture_output->u.mode;
406 }
407 
408 GuestExec *qmp_guest_exec(const char *path,
409                        bool has_arg, strList *arg,
410                        bool has_env, strList *env,
411                        const char *input_data,
412                        GuestExecCaptureOutput *capture_output,
413                        Error **errp)
414 {
415     GPid pid;
416     GuestExec *ge = NULL;
417     GuestExecInfo *gei;
418     char **argv, **envp;
419     strList arglist;
420     gboolean ret;
421     GError *gerr = NULL;
422     gint in_fd, out_fd, err_fd;
423     GIOChannel *in_ch, *out_ch, *err_ch;
424     GSpawnFlags flags;
425     bool has_output = false;
426     bool has_merge = false;
427     GuestExecCaptureOutputMode output_mode;
428     g_autofree uint8_t *input = NULL;
429     size_t ninput = 0;
430 
431     arglist.value = (char *)path;
432     arglist.next = has_arg ? arg : NULL;
433 
434     if (input_data) {
435         input = qbase64_decode(input_data, -1, &ninput, errp);
436         if (!input) {
437             return NULL;
438         }
439     }
440 
441     argv = guest_exec_get_args(&arglist, true);
442     envp = has_env ? guest_exec_get_args(env, false) : NULL;
443 
444     flags = G_SPAWN_SEARCH_PATH | G_SPAWN_DO_NOT_REAP_CHILD |
445         G_SPAWN_SEARCH_PATH_FROM_ENVP;
446 
447     output_mode = ga_parse_capture_output(capture_output);
448     switch (output_mode) {
449     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_NONE:
450         flags |= G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL;
451         break;
452     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_STDOUT:
453         has_output = true;
454         flags |= G_SPAWN_STDERR_TO_DEV_NULL;
455         break;
456     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_STDERR:
457         has_output = true;
458         flags |= G_SPAWN_STDOUT_TO_DEV_NULL;
459         break;
460     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_SEPARATED:
461         has_output = true;
462         break;
463 #if !defined(G_OS_WIN32)
464     case GUEST_EXEC_CAPTURE_OUTPUT_MODE_MERGED:
465         has_output = true;
466         has_merge = true;
467         break;
468 #endif
469     case GUEST_EXEC_CAPTURE_OUTPUT_MODE__MAX:
470         /* Silence warning; impossible branch */
471         break;
472     }
473 
474     ret = g_spawn_async_with_pipes(NULL, argv, envp, flags,
475             guest_exec_task_setup, &has_merge, &pid, input_data ? &in_fd : NULL,
476             has_output ? &out_fd : NULL, has_output ? &err_fd : NULL, &gerr);
477     if (!ret) {
478         error_setg(errp, QERR_QGA_COMMAND_FAILED, gerr->message);
479         g_error_free(gerr);
480         goto done;
481     }
482 
483     ge = g_new0(GuestExec, 1);
484     ge->pid = gpid_to_int64(pid);
485 
486     gei = guest_exec_info_add(pid);
487     gei->has_output = has_output;
488     g_child_watch_add(pid, guest_exec_child_watch, gei);
489 
490     if (input_data) {
491         gei->in.data = g_steal_pointer(&input);
492         gei->in.size = ninput;
493 #ifdef G_OS_WIN32
494         in_ch = g_io_channel_win32_new_fd(in_fd);
495 #else
496         in_ch = g_io_channel_unix_new(in_fd);
497 #endif
498         g_io_channel_set_encoding(in_ch, NULL, NULL);
499         g_io_channel_set_buffered(in_ch, false);
500         g_io_channel_set_flags(in_ch, G_IO_FLAG_NONBLOCK, NULL);
501         g_io_channel_set_close_on_unref(in_ch, true);
502         g_io_add_watch(in_ch, G_IO_OUT, guest_exec_input_watch, &gei->in);
503     }
504 
505     if (has_output) {
506 #ifdef G_OS_WIN32
507         out_ch = g_io_channel_win32_new_fd(out_fd);
508         err_ch = g_io_channel_win32_new_fd(err_fd);
509 #else
510         out_ch = g_io_channel_unix_new(out_fd);
511         err_ch = g_io_channel_unix_new(err_fd);
512 #endif
513         g_io_channel_set_encoding(out_ch, NULL, NULL);
514         g_io_channel_set_encoding(err_ch, NULL, NULL);
515         g_io_channel_set_buffered(out_ch, false);
516         g_io_channel_set_buffered(err_ch, false);
517         g_io_channel_set_close_on_unref(out_ch, true);
518         g_io_channel_set_close_on_unref(err_ch, true);
519         g_io_add_watch(out_ch, G_IO_IN | G_IO_HUP,
520                 guest_exec_output_watch, &gei->out);
521         g_io_add_watch(err_ch, G_IO_IN | G_IO_HUP,
522                 guest_exec_output_watch, &gei->err);
523     }
524 
525 done:
526     g_free(argv);
527     g_free(envp);
528 
529     return ge;
530 }
531 
532 /* Convert GuestFileWhence (either a raw integer or an enum value) into
533  * the guest's SEEK_ constants.  */
534 int ga_parse_whence(GuestFileWhence *whence, Error **errp)
535 {
536     /*
537      * Exploit the fact that we picked values to match QGA_SEEK_*;
538      * however, we have to use a temporary variable since the union
539      * members may have different size.
540      */
541     if (whence->type == QTYPE_QSTRING) {
542         int value = whence->u.name;
543         whence->type = QTYPE_QNUM;
544         whence->u.value = value;
545     }
546     switch (whence->u.value) {
547     case QGA_SEEK_SET:
548         return SEEK_SET;
549     case QGA_SEEK_CUR:
550         return SEEK_CUR;
551     case QGA_SEEK_END:
552         return SEEK_END;
553     }
554     error_setg(errp, "invalid whence code %"PRId64, whence->u.value);
555     return -1;
556 }
557 
558 GuestHostName *qmp_guest_get_host_name(Error **errp)
559 {
560     GuestHostName *result = NULL;
561     g_autofree char *hostname = qga_get_host_name(errp);
562 
563     /*
564      * We want to avoid using g_get_host_name() because that
565      * caches the result and we wouldn't reflect changes in the
566      * host name.
567      */
568 
569     if (!hostname) {
570         hostname = g_strdup("localhost");
571     }
572 
573     result = g_new0(GuestHostName, 1);
574     result->host_name = g_steal_pointer(&hostname);
575     return result;
576 }
577 
578 GuestTimezone *qmp_guest_get_timezone(Error **errp)
579 {
580     GuestTimezone *info = NULL;
581     GTimeZone *tz = NULL;
582     gint64 now = 0;
583     gint32 intv = 0;
584     gchar const *name = NULL;
585 
586     info = g_new0(GuestTimezone, 1);
587     tz = g_time_zone_new_local();
588     if (tz == NULL) {
589         error_setg(errp, QERR_QGA_COMMAND_FAILED,
590                    "Couldn't retrieve local timezone");
591         goto error;
592     }
593 
594     now = g_get_real_time() / G_USEC_PER_SEC;
595     intv = g_time_zone_find_interval(tz, G_TIME_TYPE_UNIVERSAL, now);
596     info->offset = g_time_zone_get_offset(tz, intv);
597     name = g_time_zone_get_abbreviation(tz, intv);
598     if (name != NULL) {
599         info->zone = g_strdup(name);
600     }
601     g_time_zone_unref(tz);
602 
603     return info;
604 
605 error:
606     g_free(info);
607     return NULL;
608 }
609 
610 GuestFileRead *qmp_guest_file_read(int64_t handle, bool has_count,
611                                    int64_t count, Error **errp)
612 {
613     GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
614     GuestFileRead *read_data;
615 
616     if (!gfh) {
617         return NULL;
618     }
619     if (!has_count) {
620         count = QGA_READ_COUNT_DEFAULT;
621     } else if (count < 0 || count > GUEST_FILE_READ_COUNT_MAX) {
622         error_setg(errp, "value '%" PRId64 "' is invalid for argument count",
623                    count);
624         return NULL;
625     }
626 
627     read_data = guest_file_read_unsafe(gfh, count, errp);
628     if (!read_data) {
629         slog("guest-file-write failed, handle: %" PRId64, handle);
630     }
631 
632     return read_data;
633 }
634 
635 int64_t qmp_guest_get_time(Error **errp)
636 {
637     return g_get_real_time() * 1000;
638 }
639