Add check-value support and check /proc/cmdline for cros_nodebug

utility/crossystem_main.c

 /* Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Chrome OS firmware/system interface utility
  */
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 52 matching lines @@
 void PrintHelp(const char *progname) {
   const Param *p;
 
   printf("\nUsage:\n"
          "  %s\n"
          "    Prints all parameters with descriptions and current values.\n"
          "  %s [param1 [param2 [...]]]\n"
          "    Prints the current value(s) of the parameter(s).\n"
          "  %s [param1=value1] [param2=value2 [...]]]\n"
          "    Sets the parameter(s) to the specified value(s).\n"
+         "  %s [param1?value1] [param2?value2 [...]]]\n"
+         "    Checks if the parameter(s) all contain the specified value(s).\n"
+         "Stops at the first error."
          "\n"
-         "Valid parameters:\n", progname, progname, progname);
+         "Valid parameters:\n", progname, progname, progname, progname);
   for (p = sys_param_list; p->name; p++)
     printf("  %-22s  %s\n", p->name, p->desc);
 }
 
 
 /* Find the parameter in the list.
  *
  * Returns the parameter, or NULL if no match. */
 const Param* FindParam(const char* name) {
   const Param* p;
@@ skipping 17 matching lines @@
   } else {
     char* e;
     int i = strtol(value, &e, 0);
     if (!*value || (e && *e))
       return 1;
     return (0 == VbSetSystemPropertyInt(p->name, i) ? 0 : 1);
   }
 }
 
 
+/* Compares the parameter with the expected value.
+ *
+ * Returns 0 if success (match), non-zero if error (mismatch). */
+int CheckParam(const Param* p, char* expect) {
+  if (p->is_string) {
+    char buf[256];
+    const char* v = VbGetSystemPropertyString(p->name, buf, sizeof(buf));
+    if (!v || 0 != strcmp(v, expect))
+      return 1;
+  } else {
+    char* e;
+    int i = strtol(expect, &e, 0);

[Will Drewry, 2011/03/11 02:47:17]

nit: long != int, always.

this will likely throw a warning when building 64-bit, but unlikely to be a
problem ever in practice.

+    int v = VbGetSystemPropertyInt(p->name);
+    if (!*expect || (e && *e))
+      return 1;
+    if (v == -1 || i != v)

[gauravsh, 2011/03/11 02:39:35]

since you use yoda comparisons everywhere else, might as well do it here (-1 ==
v)

+      return 1;
+  }
+  return 0;
+}
+
+
 /* Print the specified parameter.
  *
  * Returns 0 if success, non-zero if error. */
 int PrintParam(const Param* p) {
   if (p->is_string) {
     char buf[256];
     const char* v = VbGetSystemPropertyString(p->name, buf, sizeof(buf));
     if (!v)
       return 1;
     printf("%s", v);
@@ skipping 50 matching lines @@
     return PrintAllParams();
 
   /* Print help if needed */
   if (!strcasecmp(argv[1], "-h") || !strcmp(argv[1], "-?")) {
     PrintHelp(progname);
     return 0;
   }
 
   /* Otherwise, loop through params and get/set them */
   for (i = 1; i < argc && retval == 0; i++) {
-    char* name = strtok(argv[i], "=");
-    char* value = strtok(NULL, "=");
+    int has_set = (NULL != strchr(argv[i], '='));
+    int has_expect = (NULL != strchr(argv[i], '?'));
+    char* name = strtok(argv[i], "=?");
+    char* value = strtok(NULL, "=?");
     const Param* p = FindParam(name);
     if (!p) {
       fprintf(stderr, "Invalid parameter name: %s\n", name);
       PrintHelp(progname);
       return 1;
     }
 
     if (i > 1)
       printf(" ");  /* Output params space-delimited */
-    if (value)
+    if (has_set)
       retval = SetParam(p, value);
+    else if (has_expect)

[Will Drewry, 2011/03/11 02:47:17]

Do you want a check for has_set && has_expect to bail out? 

Not a big deal, but just thinking it could help catch typos or misuse.

+      retval = CheckParam(p, value);
     else
       retval = PrintParam(p);
   }
 
   return retval;
 }