From d697e30cfff29a6a72e3197a218294ba52e7f0c6 Mon Sep 17 00:00:00 2001 From: Yuri Pudgorodskiy Date: Tue, 13 Oct 2015 18:41:20 +0300 Subject: [PATCH] qga: guest exec functionality Guest-exec rewritten in platform-independent style with glib spawn. Child process is spawn asynchronously and exit status can later be picked up by guest-exec-status command. stdin/stdout/stderr of the child now is redirected to /dev/null Later we will add ability to specify stdin in guest-exec command and to get collected stdout/stderr with guest-exec-status. Signed-off-by: Yuri Pudgorodskiy Signed-off-by: Denis V. Lunev CC: Michael Roth * use g_new0 in place of g_malloc for GuestExec struct * commit msg spelling fixes * s/inp-data/input-data * document capture-input mode as false by default * use GetProcessId() for pids on w32 instead of casting HANDLE Signed-off-by: Michael Roth --- qga/commands.c | 199 +++++++++++++++++++++++++++++++++++++++++++ qga/qapi-schema.json | 62 ++++++++++++++ 2 files changed, 261 insertions(+) diff --git a/qga/commands.c b/qga/commands.c index 9a765e8bfb..ced72d503e 100644 --- a/qga/commands.c +++ b/qga/commands.c @@ -70,3 +70,202 @@ struct GuestAgentInfo *qmp_guest_info(Error **errp) qmp_for_each_command(qmp_command_info, info); return info; } + +struct GuestExecInfo { + GPid pid; + int64_t pid_numeric; + gint status; + bool finished; + QTAILQ_ENTRY(GuestExecInfo) next; +}; +typedef struct GuestExecInfo GuestExecInfo; + +static struct { + QTAILQ_HEAD(, GuestExecInfo) processes; +} guest_exec_state = { + .processes = QTAILQ_HEAD_INITIALIZER(guest_exec_state.processes), +}; + +static int64_t gpid_to_int64(GPid pid) +{ +#ifdef G_OS_WIN32 + return GetProcessId(pid); +#else + return (int64_t)pid; +#endif +} + +static GuestExecInfo *guest_exec_info_add(GPid pid) +{ + GuestExecInfo *gei; + + gei = g_new0(GuestExecInfo, 1); + gei->pid = pid; + gei->pid_numeric = gpid_to_int64(pid); + QTAILQ_INSERT_TAIL(&guest_exec_state.processes, gei, next); + + return gei; +} + +static GuestExecInfo *guest_exec_info_find(int64_t pid_numeric) +{ + GuestExecInfo *gei; + + QTAILQ_FOREACH(gei, &guest_exec_state.processes, next) { + if (gei->pid_numeric == pid_numeric) { + return gei; + } + } + + return NULL; +} + +GuestExecStatus *qmp_guest_exec_status(int64_t pid, Error **err) +{ + GuestExecInfo *gei; + GuestExecStatus *ges; + + slog("guest-exec-status called, pid: %u", (uint32_t)pid); + + gei = guest_exec_info_find(pid); + if (gei == NULL) { + error_setg(err, QERR_INVALID_PARAMETER, "pid"); + return NULL; + } + + ges = g_new0(GuestExecStatus, 1); + ges->exited = gei->finished; + + if (gei->finished) { + /* Glib has no portable way to parse exit status. + * On UNIX, we can get either exit code from normal termination + * or signal number. + * On Windows, it is either the same exit code or the exception + * value for an unhandled exception that caused the process + * to terminate. + * See MSDN for GetExitCodeProcess() and ntstatus.h for possible + * well-known codes, e.g. C0000005 ACCESS_DENIED - analog of SIGSEGV + * References: + * https://msdn.microsoft.com/en-us/library/windows/desktop/ms683189(v=vs.85).aspx + * https://msdn.microsoft.com/en-us/library/aa260331(v=vs.60).aspx + */ +#ifdef G_OS_WIN32 + /* Additionally WIN32 does not provide any additional information + * on whetherthe child exited or terminated via signal. + * We use this simple range check to distingish application exit code + * (usually value less then 256) and unhandled exception code with + * ntstatus (always value greater then 0xC0000005). */ + if ((uint32_t)gei->status < 0xC0000000U) { + ges->has_exitcode = true; + ges->exitcode = gei->status; + } else { + ges->has_signal = true; + ges->signal = gei->status; + } +#else + if (WIFEXITED(gei->status)) { + ges->has_exitcode = true; + ges->exitcode = WEXITSTATUS(gei->status); + } else if (WIFSIGNALED(gei->status)) { + ges->has_signal = true; + ges->signal = WTERMSIG(gei->status); + } +#endif + QTAILQ_REMOVE(&guest_exec_state.processes, gei, next); + g_free(gei); + } + + return ges; +} + +/* Get environment variables or arguments array for execve(). */ +static char **guest_exec_get_args(const strList *entry, bool log) +{ + const strList *it; + int count = 1, i = 0; /* reserve for NULL terminator */ + char **args; + char *str; /* for logging array of arguments */ + size_t str_size = 1; + + for (it = entry; it != NULL; it = it->next) { + count++; + str_size += 1 + strlen(it->value); + } + + str = g_malloc(str_size); + *str = 0; + args = g_malloc(count * sizeof(char *)); + for (it = entry; it != NULL; it = it->next) { + args[i++] = it->value; + pstrcat(str, str_size, it->value); + if (it->next) { + pstrcat(str, str_size, " "); + } + } + args[i] = NULL; + + if (log) { + slog("guest-exec called: \"%s\"", str); + } + g_free(str); + + return args; +} + +static void guest_exec_child_watch(GPid pid, gint status, gpointer data) +{ + GuestExecInfo *gei = (GuestExecInfo *)data; + + g_debug("guest_exec_child_watch called, pid: %d, status: %u", + (int32_t)gpid_to_int64(pid), (uint32_t)status); + + gei->status = status; + gei->finished = true; + + g_spawn_close_pid(pid); +} + +GuestExec *qmp_guest_exec(const char *path, + bool has_arg, strList *arg, + bool has_env, strList *env, + bool has_input_data, const char *input_data, + bool has_capture_output, bool capture_output, + Error **err) +{ + GPid pid; + GuestExec *ge = NULL; + GuestExecInfo *gei; + char **argv, **envp; + strList arglist; + gboolean ret; + GError *gerr = NULL; + + arglist.value = (char *)path; + arglist.next = has_arg ? arg : NULL; + + argv = guest_exec_get_args(&arglist, true); + envp = guest_exec_get_args(has_env ? env : NULL, false); + + ret = g_spawn_async_with_pipes(NULL, argv, envp, + G_SPAWN_SEARCH_PATH | + G_SPAWN_DO_NOT_REAP_CHILD | + G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL, + NULL, NULL, &pid, NULL, NULL, NULL, &gerr); + if (!ret) { + error_setg(err, QERR_QGA_COMMAND_FAILED, gerr->message); + g_error_free(gerr); + goto done; + } + + ge = g_new0(GuestExec, 1); + ge->pid = gpid_to_int64(pid); + + gei = guest_exec_info_add(pid); + g_child_watch_add(pid, guest_exec_child_watch, gei); + +done: + g_free(argv); + g_free(envp); + + return ge; +} diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json index 82894c63db..4900b5e937 100644 --- a/qga/qapi-schema.json +++ b/qga/qapi-schema.json @@ -930,3 +930,65 @@ ## { 'command': 'guest-get-memory-block-info', 'returns': 'GuestMemoryBlockInfo' } + +# @GuestExecStatus: +# +# @exited: true if process has already terminated. +# @exitcode: #optional process exit code if it was normally terminated. +# @signal: #optional signal number (linux) or unhandled exception code +# (windows) if the process was abnormally terminated. +# @out-data: #optional base64-encoded stdout of the process +# @err-data: #optional base64-encoded stderr of the process +# Note: @out-data and @err-data are present only +# if 'capture-output' was specified for 'guest-exec' +# +# Since: 2.5 +## +{ 'struct': 'GuestExecStatus', + 'data': { 'exited': 'bool', '*exitcode': 'int', '*signal': 'int', + '*out-data': 'str', '*err-data': 'str' }} +## +# @guest-exec-status +# +# Check status of process associated with PID retrieved via guest-exec. +# Reap the process and associated metadata if it has exited. +# +# @pid: pid returned from guest-exec +# +# Returns: GuestExecStatus on success. +# +# Since 2.5 +## +{ 'command': 'guest-exec-status', + 'data': { 'pid': 'int' }, + 'returns': 'GuestExecStatus' } + +## +# @GuestExec: +# @pid: pid of child process in guest OS +# +#Since: 2.5 +## +{ 'struct': 'GuestExec', + 'data': { 'pid': 'int'} } + +## +# @guest-exec: +# +# Execute a command in the guest +# +# @path: path or executable name to execute +# @arg: #optional argument list to pass to executable +# @env: #optional environment variables to pass to executable +# @input-data: #optional data to be passed to process stdin (base64 encoded) +# @capture-output: #optional bool flag to enable capture of +# stdout/stderr of running process. defaults to false. +# +# Returns: PID on success. +# +# Since: 2.5 +## +{ 'command': 'guest-exec', + 'data': { 'path': 'str', '*arg': ['str'], '*env': ['str'], + '*input-data': 'str', '*capture-output': 'bool' }, + 'returns': 'GuestExec' }