Merge pull request #16 from ilya-fedin/persistent-parent

Fork when starting application and wait for process to complete

AppRun.c.patch

@@ -1,17 +1,38 @@
 --- a/AppRun.c
 +++ b/AppRun.c
-@@ -164,6 +164,10 @@
+@@ -32,6 +32,7 @@
-     char *old_env;
+ #include <dirent.h>
+ #include <string.h>
+ #include <errno.h>
++#include <wait.h>
+ 
+ #define die(...)                                    \
+     do {                                            \
+@@ -102,6 +103,11 @@
+             line[n] = '\0';
+     }
+ 
++    int pid;
++    if ((pid = fork()) == -1) {
++        int error = errno;
++        die("fork() failed: %s\n", strerror(error));
++    } else if (pid == 0) {
+     // count arguments
+     char*   arg         = exe;
+     int     argcount    = 0;
+@@ -165,6 +171,11 @@
      size_t length;
      const char *format;
+ 
 +    checkrt(usr_in_appdir);
 +
 +    if (optional_ld_preload)
 +        putenv(optional_ld_preload);
- 
++
      /* https://docs.python.org/2/using/cmdline.html#envvar-PYTHONHOME */
      SET_NEW_ENV(new_pythonhome, appdir_s, "PYTHONHOME=%s/usr/", appdir);
-@@ -172,7 +176,7 @@
+ 
+@@ -172,7 +183,7 @@
      SET_NEW_ENV(new_path, appdir_s*5 + strlen(old_env), "PATH=%s/usr/bin/:%s/usr/sbin/:%s/usr/games/:%s/bin/:%s/sbin/:%s", appdir, appdir, appdir, appdir, appdir, old_env);
  
      old_env = getenv("LD_LIBRARY_PATH") ?: "";
@@ -20,13 +41,58 @@
  
      old_env = getenv("PYTHONPATH") ?: "";
      SET_NEW_ENV(new_pythonpath, appdir_s + strlen(old_env), "PYTHONPATH=%s/usr/share/pyshared/:%s", appdir, old_env);
-@@ -201,6 +205,9 @@
+@@ -196,16 +207,29 @@
-     if (ret == -1)
+     /* Otherwise may get errors because Python cannot write __pycache__ bytecode cache */
-         die("Error executing '%s': %s\n", exe, strerror(error));
+     putenv("PYTHONDONTWRITEBYTECODE=1");
  
+-    /* Run */
+-    ret = execvp(exe, outargptrs);
++    /* Set pid & ppid */
++    pid_t pid = getpid();
++    pid_t ppid = getppid();
+ 
+-    int error = errno;
++    int pid_len = snprintf(NULL, 0, "%d", pid);
++    int ppid_len = snprintf(NULL, 0, "%d", ppid);
+ 
+-    if (ret == -1)
+-        die("Error executing '%s': %s\n", exe, strerror(error));
++    char *s_pid = malloc(pid_len + 1);
++    snprintf(s_pid, pid_len + 1, "%d", pid);
++
++    char *s_ppid = malloc(ppid_len + 1);
++    snprintf(s_ppid, ppid_len + 1, "%d", ppid);
++
++    setenv("PID", s_pid, 1);
++    setenv("PPID", s_ppid, 1);
++
++    /* Run */
++    execvp(exe, outargptrs);
++
 +    free(optional_ld_library_path);
 +    if (optional_ld_preload)
 +        free(optional_ld_preload);
-     free(line);
+ 
-     free(desktop_file);
+-    free(line);
+-    free(desktop_file);
      free(usr_in_appdir);
+     free(new_pythonhome);
+     free(new_path);
+@@ -215,5 +239,16 @@
+     free(new_perllib);
+     free(new_gsettings_schema_dir);
+     free(new_qt_plugin_path);
+-    return 0;
++
++    int error = errno;
++    die("Error executing '%s': %s\n", exe, strerror(error));
++    }
++
++    int status = 0;
++    int rv = waitpid(pid, &status, 0);
++    status = rv > 0 && WIFEXITED (status) ? WEXITSTATUS (status) : 1;
++
++    free(line);
++    free(desktop_file);
++    return status;
+ }

Makefile

@@ -38,6 +38,6 @@ AppRun_patched.c: AppRun.c
 	patch -p1 --output $@  < AppRun.c.patch
 
 AppRun.c:
-	wget -c "https://raw.githubusercontent.com/AppImage/AppImageKit/appimagetool/master/src/AppRun.c"
+	wget -c "https://raw.githubusercontent.com/AppImage/AppImageKit/master/src/AppRun.c"
 
 .PHONY: checkrt test run_tests all clean

env.c

@@ -43,6 +43,21 @@ void env_free(char* const *env) {
     free((char**)env);
 }
 
+pid_t get_parent_pid() {
+    pid_t ppid = 0;
+    char *s_ppid = getenv("PPID");
+
+    if(s_ppid) {
+        ppid = atoi(s_ppid);
+    }
+
+    if (!ppid) {
+        ppid = getppid();
+    }
+
+    return ppid;
+}
+
 static size_t get_number_of_variables(FILE *file, char **buffer, size_t *len) {
     size_t number = 0;
 
@@ -103,7 +118,7 @@ static char* const* read_env_from_process(pid_t pid) {
 }
 
 char* const* read_parent_env() {
-    pid_t ppid = getppid();
+    pid_t ppid = get_parent_pid();
     return read_env_from_process(ppid);
 }
 

env.h

@@ -3,6 +3,7 @@
 
 #include <unistd.h>
 
+pid_t get_parent_pid();
 char* const* read_parent_env();
 void env_free(char* const *env);
 

exec.c

@@ -79,13 +79,13 @@ static int exec_common(execve_func_t function, const char *filename, char* const
     DEBUG("filename %s, fullpath %s\n", filename, fullpath);
     char* const *env = envp;
     if (is_external_process(fullpath)) {
-        DEBUG("External process detected. Restoring env vars from parent %d\n", getppid());
+        DEBUG("External process detected. Restoring env vars from parent %d\n", get_parent_pid());
         env = read_parent_env();
-        if (!env)
+        if (!env) {
             env = envp;
-        else
             DEBUG("Error restoring env vars from parent\n");
         }
+    }
     int ret = function(filename, argv, env);
 
     if (fullpath != filename)