libprocessgroup: Better error checking for string -> int conversion

There are a few calls to strtol which don't check errno for conversion
failures. android::base::ParseInt does a better job with the error
checking so switch over to that from readLong.

Change-Id: I812922bf16414608ff226b45b147a9ec3213d01e
diff --git a/libprocessgroup/task_profiles.cpp b/libprocessgroup/task_profiles.cpp
index c03c257..89ca7f1 100644
--- a/libprocessgroup/task_profiles.cpp
+++ b/libprocessgroup/task_profiles.cpp
@@ -20,7 +20,6 @@
 #include <task_profiles.h>
 
 #include <map>
-#include <optional>
 #include <string>
 
 #include <dirent.h>
@@ -31,6 +30,7 @@
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/parseint.h>
 #include <android-base/properties.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
@@ -121,15 +121,6 @@
     return path.find("<uid>", 0) != std::string::npos || path.find("<pid>", 0) != std::string::npos;
 }
 
-std::optional<long> readLong(const std::string& str) {
-    char* end;
-    const long result = strtol(str.c_str(), &end, 10);
-    if (end > str.c_str()) {
-        return result;
-    }
-    return std::nullopt;
-}
-
 }  // namespace
 
 IProfileAttribute::~IProfileAttribute() = default;
@@ -930,9 +921,8 @@
                 }
             } else if (action_name == "SetTimerSlack") {
                 const std::string slack_string = params_val["Slack"].asString();
-                std::optional<long> slack = readLong(slack_string);
-                if (slack && *slack >= 0) {
-                    profile->Add(std::make_unique<SetTimerSlackAction>(*slack));
+                if (long slack; android::base::ParseInt(slack_string, &slack) && slack >= 0) {
+                    profile->Add(std::make_unique<SetTimerSlackAction>(slack));
                 } else {
                     LOG(WARNING) << "SetTimerSlack: invalid parameter: " << slack_string;
                 }
@@ -994,18 +984,17 @@
                         // to setpriority(), since the sched_priority value must be 0 for calls to
                         // sched_setscheduler() with "normal" policies.
                         const std::string nice_string = params_val["Nice"].asString();
-                        const std::optional<int> nice = readLong(nice_string);
-
-                        if (!nice) {
+                        int nice;
+                        if (!android::base::ParseInt(nice_string, &nice)) {
                             LOG(FATAL) << "Invalid nice value specified: " << nice_string;
                         }
                         const int LINUX_MIN_NICE = -20;
                         const int LINUX_MAX_NICE = 19;
-                        if (*nice < LINUX_MIN_NICE || *nice > LINUX_MAX_NICE) {
-                            LOG(WARNING) << "SetSchedulerPolicy: Provided nice (" << *nice
+                        if (nice < LINUX_MIN_NICE || nice > LINUX_MAX_NICE) {
+                            LOG(WARNING) << "SetSchedulerPolicy: Provided nice (" << nice
                                          << ") appears out of range.";
                         }
-                        profile->Add(std::make_unique<SetSchedulerPolicyAction>(policy, *nice));
+                        profile->Add(std::make_unique<SetSchedulerPolicyAction>(policy, nice));
                     } else {
                         profile->Add(std::make_unique<SetSchedulerPolicyAction>(policy));
                     }
@@ -1020,10 +1009,11 @@
                     // [sched_get_priority_min(), sched_get_priority_max()]
 
                     const std::string priority_string = params_val["Priority"].asString();
-                    std::optional<long> virtual_priority = readLong(priority_string);
-                    if (virtual_priority && *virtual_priority > 0) {
+                    if (long virtual_priority;
+                        android::base::ParseInt(priority_string, &virtual_priority) &&
+                        virtual_priority > 0) {
                         int priority;
-                        if (SetSchedulerPolicyAction::toPriority(policy, *virtual_priority,
+                        if (SetSchedulerPolicyAction::toPriority(policy, virtual_priority,
                                                                  priority)) {
                             profile->Add(
                                     std::make_unique<SetSchedulerPolicyAction>(policy, priority));