commit 373a3cadd7d0d221e1c3e1976a0fb0c6a1c34f9f
author Steve Muckle <smuckle@google.com> Fri Dec 06 17:08:09 2019 -0800
committer Steve Muckle <smuckle@google.com> Fri Dec 27 13:39:23 2019 -0800
tree a90243c25eed12c77d41e35b6360b34be770f36f
parent ee08c978d2d34b3ddac420f9cbdc6ec65286c1e8

libmodprobe: parse kernel command line for module options

Bug: 145808811
Test: atest libmodprobe_tests, verify on flame
Change-Id: I0b41b1610fe13ae526d38f029da888f6f0d8a02d

libmodprobe/libmodprobe.cpp

diff --git a/libmodprobe/libmodprobe.cpp b/libmodprobe/libmodprobe.cpp
index 6b9107f..f22bbf1 100644
--- a/libmodprobe/libmodprobe.cpp
+++ b/libmodprobe/libmodprobe.cpp
@@ -238,6 +238,80 @@
     return;
 }
 
+void Modprobe::AddOption(const std::string& module_name, const std::string& option_name,
+                         const std::string& value) {
+    auto canonical_name = MakeCanonical(module_name);
+    auto options_iter = module_options_.find(canonical_name);
+    auto option_str = option_name + "=" + value;
+    if (options_iter != module_options_.end()) {
+        options_iter->second = options_iter->second + " " + option_str;
+    } else {
+        module_options_.emplace(canonical_name, option_str);
+    }
+}
+
+void Modprobe::ParseKernelCmdlineOptions(void) {
+    std::string cmdline = GetKernelCmdline();
+    std::string module_name = "";
+    std::string option_name = "";
+    std::string value = "";
+    bool in_module = true;
+    bool in_option = false;
+    bool in_value = false;
+    bool in_quotes = false;
+    int start = 0;
+
+    for (int i = 0; i < cmdline.size(); i++) {
+        if (cmdline[i] == '"') {
+            in_quotes = !in_quotes;
+        }
+
+        if (in_quotes) continue;
+
+        if (cmdline[i] == ' ') {
+            if (in_value) {
+                value = cmdline.substr(start, i - start);
+                if (!module_name.empty() && !option_name.empty()) {
+                    AddOption(module_name, option_name, value);
+                }
+            }
+            module_name = "";
+            option_name = "";
+            value = "";
+            in_value = false;
+            start = i + 1;
+            in_module = true;
+            continue;
+        }
+
+        if (cmdline[i] == '.') {
+            if (in_module) {
+                module_name = cmdline.substr(start, i - start);
+                start = i + 1;
+                in_module = false;
+            }
+            in_option = true;
+            continue;
+        }
+
+        if (cmdline[i] == '=') {
+            if (in_option) {
+                option_name = cmdline.substr(start, i - start);
+                start = i + 1;
+                in_option = false;
+            }
+            in_value = true;
+            continue;
+        }
+    }
+    if (in_value && !in_quotes) {
+        value = cmdline.substr(start, cmdline.size() - start);
+        if (!module_name.empty() && !option_name.empty()) {
+            AddOption(module_name, option_name, value);
+        }
+    }
+}
+
 Modprobe::Modprobe(const std::vector<std::string>& base_paths) {
     using namespace std::placeholders;
 
@@ -261,6 +335,7 @@
         ParseCfg(base_path + "/modules.blacklist", blacklist_callback);
     }
 
+    ParseKernelCmdlineOptions();
     android::base::SetMinimumLogSeverity(android::base::INFO);
 }