qga/service-win32.c

   1 /*
   2  * QEMU Guest Agent helpers for win32 service management
   3  *
   4  * Copyright IBM Corp. 2012
   5  *
   6  * Authors:
   7  *  Gal Hammer        <ghammer@redhat.com>
   8  *  Michael Roth      <mdroth@linux.vnet.ibm.com>
   9  *
  10  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  11  * See the COPYING file in the top-level directory.
  12  */
  13 #include "qemu/osdep.h"
  14 #include <glib.h>
  15 #include <windows.h>
  16 #include "qga/service-win32.h"
  17
  18 static int printf_win_error(const char *text)
  19 {
  20     DWORD err = GetLastError();
  21     char *message;
  22     int n;
  23
  24     FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
  25         FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
  26         NULL,
  27         err,
  28         MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
  29         (char *)&message, 0,
  30         NULL);
  31     n = fprintf(stderr, "%s. (Error: %d) %s", text, (int)err, message);
  32     LocalFree(message);
  33
  34     return n;
  35 }
  36
  37 /* Windows command line escaping. Based on
  38  * <http://blogs.msdn.com/b/oldnewthing/archive/2010/09/17/10063629.aspx> and
  39  * <http://msdn.microsoft.com/en-us/library/windows/desktop/17w5ykft%28v=vs.85%29.aspx>.
  40  *
  41  * The caller is responsible for initializing @buffer; prior contents are lost.
  42  */
  43 static const char *win_escape_arg(const char *to_escape, GString *buffer)
  44 {
  45     size_t backslash_count;
  46     const char *c;
  47
  48     /* open with a double quote */
  49     g_string_assign(buffer, "\"");
  50
  51     backslash_count = 0;
  52     for (c = to_escape; *c != '\0'; ++c) {
  53         switch (*c) {
  54         case '\\':
  55             /* The meaning depends on the first non-backslash character coming
  56              * up.
  57              */
  58             ++backslash_count;
  59             break;
  60
  61         case '"':
  62             /* We must escape each pending backslash, then escape the double
  63              * quote. This creates a case of "odd number of backslashes [...]
  64              * followed by a double quotation mark".
  65              */
  66             while (backslash_count) {
  67                 --backslash_count;
  68                 g_string_append(buffer, "\\\\");
  69             }
  70             g_string_append(buffer, "\\\"");
  71             break;
  72
  73         default:
  74             /* Any pending backslashes are without special meaning, flush them.
  75              * "Backslashes are interpreted literally, unless they immediately
  76              * precede a double quotation mark."
  77              */
  78             while (backslash_count) {
  79                 --backslash_count;
  80                 g_string_append_c(buffer, '\\');
  81             }
  82             g_string_append_c(buffer, *c);
  83         }
  84     }
  85
  86     /* We're about to close with a double quote in string delimiter role.
  87      * Double all pending backslashes, creating a case of "even number of
  88      * backslashes [...] followed by a double quotation mark".
  89      */
  90     while (backslash_count) {
  91         --backslash_count;
  92         g_string_append(buffer, "\\\\");
  93     }
  94     g_string_append_c(buffer, '"');
  95
  96     return buffer->str;
  97 }
  98
  99 int ga_install_service(const char *path, const char *logfile,
 100                        const char *state_dir)
 101 {
 102     int ret = EXIT_FAILURE;
 103     SC_HANDLE manager;
 104     SC_HANDLE service;
 105     TCHAR module_fname[MAX_PATH];
 106     GString *esc;
 107     GString *cmdline;
 108     SERVICE_DESCRIPTION desc = { (char *)QGA_SERVICE_DESCRIPTION };
 109
 110     if (GetModuleFileName(NULL, module_fname, MAX_PATH) == 0) {
 111         printf_win_error("No full path to service's executable");
 112         return EXIT_FAILURE;
 113     }
 114
 115     esc     = g_string_new("");
 116     cmdline = g_string_new("");
 117
 118     g_string_append_printf(cmdline, "%s -d",
 119                            win_escape_arg(module_fname, esc));
 120
 121     if (path) {
 122         g_string_append_printf(cmdline, " -p %s", win_escape_arg(path, esc));
 123     }
 124     if (logfile) {
 125         g_string_append_printf(cmdline, " -l %s -v",
 126                                win_escape_arg(logfile, esc));
 127     }
 128     if (state_dir) {
 129         g_string_append_printf(cmdline, " -t %s",
 130                                win_escape_arg(state_dir, esc));
 131     }
 132
 133     g_debug("service's cmdline: %s", cmdline->str);
 134
 135     manager = OpenSCManager(NULL, NULL, SC_MANAGER_ALL_ACCESS);
 136     if (manager == NULL) {
 137         printf_win_error("No handle to service control manager");
 138         goto out_strings;
 139     }
 140
 141     service = CreateService(manager, QGA_SERVICE_NAME, QGA_SERVICE_DISPLAY_NAME,
 142         SERVICE_ALL_ACCESS, SERVICE_WIN32_OWN_PROCESS, SERVICE_AUTO_START,
 143         SERVICE_ERROR_NORMAL, cmdline->str, NULL, NULL, NULL, NULL, NULL);
 144     if (service == NULL) {
 145         printf_win_error("Failed to install service");
 146         goto out_manager;
 147     }
 148
 149     ChangeServiceConfig2(service, SERVICE_CONFIG_DESCRIPTION, &desc);
 150     fprintf(stderr, "Service was installed successfully.\n");
 151     ret = EXIT_SUCCESS;
 152     CloseServiceHandle(service);
 153
 154 out_manager:
 155     CloseServiceHandle(manager);
 156
 157 out_strings:
 158     g_string_free(cmdline, TRUE);
 159     g_string_free(esc, TRUE);
 160     return ret;
 161 }
 162
 163 int ga_uninstall_service(void)
 164 {
 165     SC_HANDLE manager;
 166     SC_HANDLE service;
 167
 168     manager = OpenSCManager(NULL, NULL, SC_MANAGER_ALL_ACCESS);
 169     if (manager == NULL) {
 170         printf_win_error("No handle to service control manager");
 171         return EXIT_FAILURE;
 172     }
 173
 174     service = OpenService(manager, QGA_SERVICE_NAME, DELETE);
 175     if (service == NULL) {
 176         printf_win_error("No handle to service");
 177         CloseServiceHandle(manager);
 178         return EXIT_FAILURE;
 179     }
 180
 181     if (DeleteService(service) == FALSE) {
 182         printf_win_error("Failed to delete service");
 183     } else {
 184         fprintf(stderr, "Service was deleted successfully.\n");
 185     }
 186
 187     CloseServiceHandle(service);
 188     CloseServiceHandle(manager);
 189
 190     return EXIT_SUCCESS;
 191 }