Changeset 5582

Timestamp:

01/11/09 13:19:32 (4 years ago)

Author:

khali

Message:

Detect excessive recursion depth during expression evaluation.

Location:

lm-sensors/branches/lm-sensors-3.0.0

Files:

• CHANGES (modified) (1 diff)
• doc/libsensors-API.txt (modified) (1 diff)
• lib/access.c (modified) (9 diffs)
• lib/error.c (modified) (2 diffs)
• lib/error.h (modified) (2 diffs)

lm-sensors/branches/lm-sensors-3.0.0/CHANGES

@@ -6 +6 @@
               Add support for current sensors
               Fix error propagation during expression evaluation
+              Detect excessive recursion depth during expression evaluation
   maxilife scripts: Delete (driver never ported to Linux 2.6)
   sensord: Accept negative temperatures in RRD database

lm-sensors/branches/lm-sensors-3.0.0/doc/libsensors-API.txt

@@ -21 +21 @@
   enum sensors_subfeature_type SENSORS_SUBFEATURE_CURR_MAX_ALARM
   enum sensors_subfeature_type SENSORS_SUBFEATURE_CURR_BEEP
+* Added error value for excessive recursion depth
+  #define SENSORS_ERR_RECURSION 11
 
 0x401   lm-sensors 3.0.2 to 3.0.3

lm-sensors/branches/lm-sensors-3.0.0/lib/access.c

@@ -2 +2 @@
     access.c - Part of libsensors, a Linux library for reading sensor data.
     Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
-    Copyright (C) 2007        Jean Delvare <khali@linux-fr.org>
+    Copyright (C) 2007, 2008  Jean Delvare <khali@linux-fr.org>
 
     This program is free software; you can redistribute it and/or modify
@@ -30 +30 @@
 #include "general.h"
 
+/* We watch the recursion depth for variables only, as an easy way to
+   detect cycles. */
+#define DEPTH_MAX       8
+
 static int sensors_eval_expr(const sensors_chip_features *chip_features,
                              const sensors_expr *expr,
-                             double val, double *result);
+                             double val, int depth, double *result);
 
 /* Compare two chips name descriptions, to see whether they could match.
@@ -222 +226 @@
    contain wildcard values! This function will return 0 on success, and <0
    on failure. */
-int sensors_get_value(const sensors_chip_name *name, int subfeat_nr,
-                      double *result)
+static int __sensors_get_value(const sensors_chip_name *name, int subfeat_nr,
+                               int depth, double *result)
 {
         const sensors_chip_features *chip_features;
@@ -231 +235 @@
         int res, i;
 
+        if (depth >= DEPTH_MAX)
+                return -SENSORS_ERR_RECURSION;
         if (sensors_chip_name_has_wildcards(name))
                 return -SENSORS_ERR_WILDCARDS;
@@ -266 +272 @@
         if (!expr)
                 *result = val;
-        else if ((res = sensors_eval_expr(chip_features, expr, val, result)))
+        else if ((res = sensors_eval_expr(chip_features, expr, val, depth,
+                                          result)))
                 return res;
         return 0;
+}
+
+int sensors_get_value(const sensors_chip_name *name, int subfeat_nr,
+                      double *result)
+{
+        return __sensors_get_value(name, subfeat_nr, 0, result);
 }
 
@@ -316 +329 @@
         if (expr)
                 if ((res = sensors_eval_expr(chip_features, expr,
-                                             value, &to_write)))
+                                             value, 0, &to_write)))
                         return res;
         return sensors_write_sysfs_attr(name, subfeature, to_write);
@@ -420 +433 @@
 int sensors_eval_expr(const sensors_chip_features *chip_features,
                       const sensors_expr *expr,
-                      double val, double *result)
+                      double val, int depth, double *result)
 {
         double res1, res2;
@@ -438 +451 @@
                                                             expr->data.var)))
                         return -SENSORS_ERR_NO_ENTRY;
-                return sensors_get_value(&chip_features->chip,
-                                         subfeature->number, result);
+                return __sensors_get_value(&chip_features->chip,
+                                           subfeature->number, depth + 1,
+                                           result);
         }
         if ((res = sensors_eval_expr(chip_features, expr->data.subexpr.sub1,
-                                     val, &res1)))
+                                     val, depth, &res1)))
                 return res;
         if (expr->data.subexpr.sub2 &&
             (res = sensors_eval_expr(chip_features, expr->data.subexpr.sub2,
-                                     val, &res2)))
+                                     val, depth, &res2)))
                 return res;
         switch (expr->data.subexpr.op) {
@@ -505 +519 @@
                         res = sensors_eval_expr(chip_features,
                                                 chip->sets[i].value, 0,
-                                                &value);
+                                                0, &value);
                         if (res) {
                                 sensors_parse_error("Error parsing expression",

lm-sensors/branches/lm-sensors-3.0.0/lib/error.c

@@ -2 +2 @@
     error.c - Part of libsensors, a Linux library for reading sensor data.
     Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
-    Copyright (C) 2007        Jean Delvare <khali@linux-fr.org>
+    Copyright (C) 2007, 2008  Jean Delvare <khali@linux-fr.org>
 
     This program is free software; you can redistribute it and/or modify
@@ -45 +45 @@
         /* SENSORS_ERR_ACCESS_W  */ "Can't write",
         /* SENSORS_ERR_IO        */ "I/O error",
+        /* SENSORS_ERR_RECURSION */ "Evaluation recurses too deep",
 };
 

lm-sensors/branches/lm-sensors-3.0.0/lib/error.h

@@ -2 +2 @@
     error.h - Part of libsensors, a Linux library for reading sensor data.
     Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
-    Copyright (C) 2007        Jean Delvare <khali@linux-fr.org>
+    Copyright (C) 2007, 2008  Jean Delvare <khali@linux-fr.org>
 
     This program is free software; you can redistribute it and/or modify
@@ -33 +33 @@
 #define SENSORS_ERR_ACCESS_W    9 /* Can't write */
 #define SENSORS_ERR_IO          10 /* I/O error */
+#define SENSORS_ERR_RECURSION   11 /* Evaluation recurses too deep */
 
 #ifdef __cplusplus