Fix stream life-time race condition by reversing ownership

libu/in_input.c

@@ -46,7 +46,7 @@ void in_stream_read_line(const char* prompt, char* buffer, size_t max) {
   for (;;) {
     uint8_t ch;
 
-    if (stream_read(process_get_pgid(), STREAM_IN, &ch, 1) <= 0) {
+    if (stream_read(STREAM_IN, &ch, 1) <= 0) {
       sched();
       continue;
     }

libu/mprintf.c

@@ -1,3 +1,4 @@
+#include <debugconsole.h>
 #include <mprintf.h>
 #include <printf.h>
 #include <process.h>
@@ -32,7 +33,7 @@ void mprintf(const char* fmt, ...) {
 
   va_end(args);
 
-  stream_write(process_get_pgid(), STREAM_OUT, mprintf_buffer, len);
+  stream_write(process_get_exec_pgid(), STREAM_OUT, mprintf_buffer, len);
 
   mprintf_buffer_unlock();
 }

libu/system.c

@@ -101,8 +101,8 @@ int stream_write(int pgid, int rid, void* buffer, size_t size) {
   return (int)do_syscall(SYS_STREAM_WRITE, pgid, rid, buffer, size);
 }
 
-int stream_read(int pgid, int rid, void* buffer, size_t size) {
-  return (int)do_syscall(SYS_STREAM_READ, pgid, rid, buffer, size);
+int stream_read(int rid, void* buffer, size_t size) {
+  return (int)do_syscall(SYS_STREAM_READ, rid, buffer, size);
 }
 
 int get_proc_info(struct proc_info* infos, size_t count) {
@@ -122,3 +122,5 @@ int volume_delete(const char* key) { return (int)do_syscall(SYS_VOLUME_DELETE, k
 int date_time(struct date_time* dt) { return (int)do_syscall(SYS_DATE_TIME, dt); }
 
 const char* get_cmdline(void) { return (const char*)do_syscall(SYS_GET_CMDLINE, 0); }
+
+int proc_is_alive(int pid) { return (int)do_syscall(SYS_PROC_IS_ALIVE, pid); }

libu/system.h

@@ -110,7 +110,7 @@ int get_self_pid(void);
 int stream_write(int pgid, int rid, void* buffer, size_t size);
 
 /* Read from a stream */
-int stream_read(int pgid, int rid, void* buffer, size_t size);
+int stream_read(int rid, void* buffer, size_t size);
 
 /* get process information */
 int get_proc_info(struct proc_info* infos, size_t count);
@@ -130,4 +130,7 @@ int date_time(struct date_time* dt);
 /* Get commandline string */
 const char* get_cmdline(void);
 
+/* check if PID is alive */
+int proc_is_alive(int pid);
+
 #endif // _LIBMSL_M_SYSTEM_H