Simplify Unix implementation of QProcess::start{Process|Detached}

Use QStandardPaths::findExecutable instead of duplicated
implementations.

Change-Id: Ia944f1d343d8c215fc2b6e78dae6b2bfffbba688
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qprocess_p.h

@@ -353,7 +353,7 @@ public:
     void start(QIODevice::OpenMode mode);
     void startProcess();
 #if defined(Q_OS_UNIX)
-    void execChild(const char *workingDirectory, char **path, char **argv, char **envp);
+    void execChild(const char *workingDirectory, char **argv, char **envp);
 #endif
     bool processStarted(QString *errorMessage = Q_NULLPTR);
     void terminateProcess();

src/corelib/io/qprocess_unix.cpp

@@ -87,6 +87,7 @@ QT_END_NAMESPACE
 
 #include "qprocess.h"
 #include "qprocess_p.h"
+#include "qstandardpaths.h"
 #include "private/qcore_unix_p.h"
 
 #ifdef Q_OS_MAC
@@ -420,8 +421,16 @@ void QProcessPrivate::startProcess()
 #endif
 
     // Add the program name to the argument list.
-    char *dupProgramName = ::strdup(encodedProgramName.constData());
+    argv[0] = nullptr;
-    argv[0] = dupProgramName;
+    if (!program.contains(QLatin1Char('/'))) {
+        const QString &exeFilePath = QStandardPaths::findExecutable(program);
+        if (!exeFilePath.isEmpty()) {
+            const QByteArray &tmp = QFile::encodeName(exeFilePath);
+            argv[0] = ::strdup(tmp.constData());
+        }
+    }
+    if (!argv[0])
+        argv[0] = ::strdup(encodedProgramName.constData());
 
     // Add every argument to the list
     for (int i = 0; i < arguments.count(); ++i)
@@ -443,29 +452,6 @@ void QProcessPrivate::startProcess()
         workingDirPtr = encodedWorkingDirectory.constData();
     }
 
-    // If the program does not specify a path, generate a list of possible
-    // locations for the binary using the PATH environment variable.
-    char **path = 0;
-    int pathc = 0;
-    if (!program.contains(QLatin1Char('/'))) {
-        const QString pathEnv = QString::fromLocal8Bit(qgetenv("PATH"));
-        if (!pathEnv.isEmpty()) {
-            QStringList pathEntries = pathEnv.split(QLatin1Char(':'), QString::SkipEmptyParts);
-            if (!pathEntries.isEmpty()) {
-                pathc = pathEntries.size();
-                path = new char *[pathc + 1];
-                path[pathc] = 0;
-
-                for (int k = 0; k < pathEntries.size(); ++k) {
-                    QByteArray tmp = QFile::encodeName(pathEntries.at(k));
-                    if (!tmp.endsWith('/')) tmp += '/';
-                    tmp += encodedProgramName;
-                    path[k] = ::strdup(tmp.constData());
-                }
-            }
-        }
-    }
-
     // Start the process manager, and fork off the child process.
     pid_t childPid;
     forkfd = ::forkfd(FFD_CLOEXEC, &childPid);
@@ -473,16 +459,12 @@ void QProcessPrivate::startProcess()
     if (forkfd != FFD_CHILD_PROCESS) {
         // Parent process.
         // Clean up duplicated memory.
-        free(dupProgramName);
+        for (int i = 0; i <= arguments.count(); ++i)
-        for (int i = 1; i <= arguments.count(); ++i)
             free(argv[i]);
         for (int i = 0; i < envc; ++i)
             free(envp[i]);
-        for (int i = 0; i < pathc; ++i)
-            free(path[i]);
         delete [] argv;
         delete [] envp;
-        delete [] path;
     }
 
     // On QNX, if spawnChild failed, childPid will be -1 but forkfd is still 0.
@@ -503,7 +485,7 @@ void QProcessPrivate::startProcess()
 
     // Start the child.
     if (forkfd == FFD_CHILD_PROCESS) {
-        execChild(workingDirPtr, path, argv, envp);
+        execChild(workingDirPtr, argv, envp);
         ::_exit(-1);
     }
 
@@ -544,7 +526,7 @@ void QProcessPrivate::startProcess()
     }
 }
 
-void QProcessPrivate::execChild(const char *workingDir, char **path, char **argv, char **envp)
+void QProcessPrivate::execChild(const char *workingDir, char **argv, char **envp)
 {
     ::signal(SIGPIPE, SIG_DFL);         // reset the signal that we ignored
 
@@ -567,7 +549,7 @@ void QProcessPrivate::execChild(const char *workingDir, char **path, char **argv
         }
     }
 
-    // make sure this fd is closed if execvp() succeeds
+    // make sure this fd is closed if execv() succeeds
     qt_safe_close(childStartedPipe[0]);
 
     // enter the working directory
@@ -582,25 +564,13 @@ void QProcessPrivate::execChild(const char *workingDir, char **path, char **argv
 
     // execute the process
     if (!envp) {
-        qt_safe_execvp(argv[0], argv);
+        qt_safe_execv(argv[0], argv);
-        callthatfailed = "execvp: ";
+        callthatfailed = "execv: ";
-    } else {
-        if (path) {
-            char **arg = path;
-            while (*arg) {
-                argv[0] = *arg;
-#if defined (QPROCESS_DEBUG)
-                fprintf(stderr, "QProcessPrivate::execChild() searching / starting %s\n", argv[0]);
-#endif
-                qt_safe_execve(argv[0], argv, envp);
-                ++arg;
-            }
     } else {
 #if defined (QPROCESS_DEBUG)
         fprintf(stderr, "QProcessPrivate::execChild() starting %s\n", argv[0]);
 #endif
         qt_safe_execve(argv[0], argv, envp);
-        }
         callthatfailed = "execve: ";
     }
 
@@ -967,23 +937,16 @@ bool QProcessPrivate::startDetached(qint64 *pid)
                 argv[i + 1] = ::strdup(QFile::encodeName(arguments.at(i)).constData());
             argv[arguments.size() + 1] = 0;
 
+            QByteArray tmp;
             if (!program.contains(QLatin1Char('/'))) {
-                const QString path = QString::fromLocal8Bit(qgetenv("PATH"));
+                const QString &exeFilePath = QStandardPaths::findExecutable(program);
-                if (!path.isEmpty()) {
+                if (!exeFilePath.isEmpty())
-                    QStringList pathEntries = path.split(QLatin1Char(':'));
+                    tmp = QFile::encodeName(exeFilePath);
-                    for (int k = 0; k < pathEntries.size(); ++k) {
+            }
-                        QByteArray tmp = QFile::encodeName(pathEntries.at(k));
+            if (tmp.isEmpty())
-                        if (!tmp.endsWith('/')) tmp += '/';
+                tmp = QFile::encodeName(program);
-                        tmp += QFile::encodeName(program);
             argv[0] = tmp.data();
             qt_safe_execv(argv[0], argv);
-                    }
-                }
-            } else {
-                QByteArray tmp = QFile::encodeName(program);
-                argv[0] = tmp.data();
-                qt_safe_execv(argv[0], argv);
-            }
 
             struct sigaction noaction;
             memset(&noaction, 0, sizeof(noaction));