[GTK][WPE] CGroupMemoryController::getCgroupFileValue not stack if no…

…t numerical value is scanned from the file input (e.g: max)

https://bugs.webkit.org/show_bug.cgi?id=273931

Reviewed by Carlos Alberto Lopez Perez.

Improves the CGroupMemoryController::getCgroupFileValue by ensuring it
handles non-numeric values (e.g., max).

Fixes TestNetworkProcessMemoryPressure API test (webkit.org/b/263016).

* Source/WebKit/UIProcess/linux/MemoryPressureMonitor.cpp:
(WebKit::CGroupMemoryController::getCgroupFileValue):
* Tools/TestWebKitAPI/glib/TestExpectations.json:

Canonical link: https://commits.webkit.org/278599@main

Source/WebKit/UIProcess/linux/MemoryPressureMonitor.cpp

@@ -67,6 +67,7 @@ static const unsigned maxCgroupPath = 4096; // PATH_MAX = 4096 from (Linux) incl
 #define MEMINFO_TOKEN_BUFFER_SIZE 50
 #define STRINGIFY_EXPANDED(val) #val
 #define STRINGIFY(val) STRINGIFY_EXPANDED(val)
+#define VALUE_BUFFER_SIZE 128
 #define ZONEINFO_TOKEN_BUFFER_SIZE 128
 
 // The lowWatermark is the sum of the low watermarks across all zones as the
@@ -438,8 +439,18 @@ size_t CGroupMemoryController::getCgroupFileValue(FILE *file)
     if (!file || fseek(file, 0, SEEK_SET))
         return notSet;
 
-    size_t value;
-    return (fscanf(file, "%zu", &value) == 1) ? value : notSet;
+    char rawValue[VALUE_BUFFER_SIZE + 1];
+    if (fscanf(file, "%" STRINGIFY(VALUE_BUFFER_SIZE) "[^\n]", rawValue) < 1)
+        return notSet;
+
+    errno = 0;
+    char* endptr;
+    long value = strtol(rawValue, &endptr, 10);
+
+    if (errno == ERANGE || value < 0 || *endptr != '\0')
+        return notSet;
+
+    return static_cast<size_t>(value);
 }
 
 size_t CGroupMemoryController::getMemoryTotalWithCgroup()

Tools/TestWebKitAPI/glib/TestExpectations.json

@@ -327,13 +327,6 @@
         }
 
     },
-    "TestNetworkProcessMemoryPressure": {
-        "subtests": {
-            "/webkit/WebKitWebsiteData/memory-pressure": {
-                "expected": {"gtk": {"status": ["TIMEOUT"], "bug": "webkit.org/b/263016"}}
-            }
-        }
-    },
     "TestWebKitNetworkSession": {
         "subtests": {
             "/webkit/WebKitNetworkSession/proxy": {