Make getpid() return non-zero number

getpid() no longer returns 0 as the pid of the kernel/application, and
instead uses the constant defined in include/osv/pid.h.

Signed-off-by: Samuel Laberge <samlaberge817@gmail.com>
Message-Id: <20201206195248.53500-2-samlaberge817@gmail.com>

fs/procfs/procfs_vnops.cc

@@ -12,6 +12,7 @@
 #include <osv/prex.h>
 #include <osv/sched.hh>
 #include <osv/mmu.hh>
+#include <osv/pid.h>
 
 #include "fs/pseudofs/pseudofs.hh"
 
@@ -177,7 +178,7 @@ procfs_mount(mount* mp, const char *dev, int flags, const void* data)
 
     auto* root = new pseudo_dir_node(vp->v_ino);
     root->add("self", self);
-    root->add("0", self); // our standard pid
+    root->add(std::to_string(OSV_PID), self); // our standard pid
     root->add("mounts", inode_count++, procfs_mounts);
     root->add("sys", sys);
 

include/osv/pid.h

@@ -0,0 +1,7 @@
+
+#ifndef _OSV_PID_H_
+#define _OSV_PID_H
+
+#define OSV_PID 2
+
+#endif

libc/signal.cc

@@ -18,6 +18,7 @@
 #include <osv/clock.hh>
 #include <api/setjmp.h>
 #include <osv/stubbing.hh>
+#include <osv/pid.h>
 
 using namespace osv::clock::literals;
 
@@ -325,17 +326,13 @@ int kill(pid_t pid, int sig)
                 sig, strsignal(sig));
         osv::poweroff();
     } else if(!is_sig_ign(signal_actions[sig])) {
-        if ((pid == 0) || (pid == -1)) {
-            // That semantically means signalling everybody (or that, or the
-            // user did getpid() and got 0, all the same. So we will signal
+        if ((pid == OSV_PID) || (pid == 0) || (pid == -1)) {
+            // This semantically means signalling everybody. So we will signal
             // every thread that is waiting for this.
             //
             // The thread does not expect the signal handler to still be delivered,
             // so if we wake up some folks (usually just the one waiter), we should
             // not continue processing.
-            //
-            // FIXME: Maybe it could be a good idea for our getpid() to start
-            // returning 1 so we can differentiate between those cases?
             if (wake_up_signal_waiters(sig)) {
                 return 0;
             }
@@ -482,7 +479,7 @@ void itimer::work()
                     } else {
                         _due = _no_alarm;
                     }
-                    kill(0, _signum);
+                    kill(getpid(), _signum);
                     if(!is_sig_ign(signal_actions[_signum])) {
                         _owner_thread->interrupted(true);
                     }

libc/unistd/getppid.c

@@ -1,6 +1,7 @@
 #include <unistd.h>
+#include <include/osv/pid.h>
 
 pid_t getppid(void)
 {
-	return 0;
+	return OSV_PID;
 }

runtime.cc

@@ -60,6 +60,7 @@
 #include <api/sys/prctl.h>
 #include <sys/wait.h>
 #include <pty.h>
+#include <osv/pid.h>
 
 #define __LC_LAST 13
 
@@ -263,7 +264,7 @@ LFS64(posix_fallocate);
 
 int getpid()
 {
-    return 0;
+    return OSV_PID;
 }
 
 //    WCTDEF(alnum), WCTDEF(alpha), WCTDEF(blank), WCTDEF(cntrl),