From c3b287be74e12bdb15ed36e98d24fd42f8ee9122 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Tue, 23 Mar 2021 22:38:54 +0000
Subject: hurd: handle EINTR during critical sections

During critical sections, signal handling is deferred and thus RPCs return
EINTR, even if SA_RESTART is set. We thus have to restart the whole critical
section in that case.

This also adds HURD_CRITICAL_UNLOCK in the cases where one wants to
break the section in the middle.
---
 sysdeps/mach/hurd/faccessat.c    |  4 ++++
 sysdeps/mach/hurd/fork.c         |  4 ++++
 sysdeps/mach/hurd/getegid.c      |  4 ++++
 sysdeps/mach/hurd/geteuid.c      |  4 ++++
 sysdeps/mach/hurd/getgid.c       |  4 ++++
 sysdeps/mach/hurd/getgroups.c    |  4 ++++
 sysdeps/mach/hurd/getresgid.c    |  4 ++++
 sysdeps/mach/hurd/getresuid.c    |  4 ++++
 sysdeps/mach/hurd/getuid.c       |  4 ++++
 sysdeps/mach/hurd/group_member.c |  4 ++++
 sysdeps/mach/hurd/setegid.c      |  4 ++++
 sysdeps/mach/hurd/seteuid.c      |  4 ++++
 sysdeps/mach/hurd/setgid.c       |  4 ++++
 sysdeps/mach/hurd/setgroups.c    |  4 ++++
 sysdeps/mach/hurd/setitimer.c    |  9 ++++++++-
 sysdeps/mach/hurd/setregid.c     |  4 ++++
 sysdeps/mach/hurd/setresgid.c    |  4 ++++
 sysdeps/mach/hurd/setresuid.c    |  4 ++++
 sysdeps/mach/hurd/setreuid.c     |  4 ++++
 sysdeps/mach/hurd/setsid.c       |  4 ++++
 sysdeps/mach/hurd/setuid.c       |  4 ++++
 sysdeps/mach/hurd/spawni.c       | 15 ++++++++++++++-
 22 files changed, 102 insertions(+), 2 deletions(-)

(limited to 'sysdeps/mach')

diff --git a/sysdeps/mach/hurd/faccessat.c b/sysdeps/mach/hurd/faccessat.c
index f421a531fe..07702712c5 100644
--- a/sysdeps/mach/hurd/faccessat.c
+++ b/sysdeps/mach/hurd/faccessat.c
@@ -127,6 +127,7 @@ __faccessat_common (int fd, const char *file, int type, int at_flags,
 
       rcrdir = rcwdir = MACH_PORT_NULL;
 
+     retry:
       HURD_CRITICAL_BEGIN;
 
       __mutex_lock (&_hurd_id.lock);
@@ -172,6 +173,9 @@ __faccessat_common (int fd, const char *file, int type, int at_flags,
       __mutex_unlock (&_hurd_id.lock);
 
       HURD_CRITICAL_END;
+      if (err == EINTR)
+	/* Got a signal while inside an RPC of the critical section, retry again */
+	goto retry;
 
       if (rcrdir != MACH_PORT_NULL)
 	__mach_port_deallocate (__mach_task_self (), rcrdir);
diff --git a/sysdeps/mach/hurd/fork.c b/sysdeps/mach/hurd/fork.c
index 1c5299e686..92a51693e0 100644
--- a/sysdeps/mach/hurd/fork.c
+++ b/sysdeps/mach/hurd/fork.c
@@ -70,6 +70,7 @@ __fork (void)
   __run_fork_handlers (atfork_run_prepare, true);
 
   ss = _hurd_self_sigstate ();
+retry:
   __spin_lock (&ss->critical_section_lock);
 
 #undef	LOSE
@@ -718,6 +719,9 @@ __fork (void)
   }
 
   _hurd_critical_section_unlock (ss);
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (!err)
     {
diff --git a/sysdeps/mach/hurd/getegid.c b/sysdeps/mach/hurd/getegid.c
index 5a3db22746..1929d749a7 100644
--- a/sysdeps/mach/hurd/getegid.c
+++ b/sysdeps/mach/hurd/getegid.c
@@ -27,6 +27,7 @@ __getegid (void)
   error_t err;
   gid_t egid;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
 
@@ -49,6 +50,9 @@ __getegid (void)
 
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (egid == -1 && errno == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   return egid;
 }
diff --git a/sysdeps/mach/hurd/geteuid.c b/sysdeps/mach/hurd/geteuid.c
index a7af5a9d0d..5312d6bf64 100644
--- a/sysdeps/mach/hurd/geteuid.c
+++ b/sysdeps/mach/hurd/geteuid.c
@@ -27,6 +27,7 @@ __geteuid (void)
   error_t err;
   uid_t euid;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
 
@@ -49,6 +50,9 @@ __geteuid (void)
 
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (euid == -1 && errno == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   return euid;
 }
diff --git a/sysdeps/mach/hurd/getgid.c b/sysdeps/mach/hurd/getgid.c
index aa13884a8f..c89e7429be 100644
--- a/sysdeps/mach/hurd/getgid.c
+++ b/sysdeps/mach/hurd/getgid.c
@@ -27,6 +27,7 @@ __getgid (void)
   error_t err;
   gid_t gid;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
 
@@ -46,6 +47,9 @@ __getgid (void)
 
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (gid == -1 && errno == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   return gid;
 }
diff --git a/sysdeps/mach/hurd/getgroups.c b/sysdeps/mach/hurd/getgroups.c
index 5f036f8191..6b59d4a483 100644
--- a/sysdeps/mach/hurd/getgroups.c
+++ b/sysdeps/mach/hurd/getgroups.c
@@ -31,6 +31,7 @@ __getgroups (int n, gid_t *gidset)
   if (n < 0)
     return __hurd_fail (EINVAL);
 
+retry:
   crit = _hurd_critical_section_lock ();
   __mutex_lock (&_hurd_id.lock);
 
@@ -38,6 +39,9 @@ __getgroups (int n, gid_t *gidset)
     {
       __mutex_unlock (&_hurd_id.lock);
       _hurd_critical_section_unlock (crit);
+      if (err == EINTR)
+	/* Got a signal while inside an RPC of the critical section, retry again */
+	goto retry;
       return __hurd_fail (err);
     }
 
diff --git a/sysdeps/mach/hurd/getresgid.c b/sysdeps/mach/hurd/getresgid.c
index 9cae591f58..52838b8b4c 100644
--- a/sysdeps/mach/hurd/getresgid.c
+++ b/sysdeps/mach/hurd/getresgid.c
@@ -28,6 +28,7 @@ __getresgid (gid_t *rgid, gid_t *egid, gid_t *sgid)
 {
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
 
@@ -49,6 +50,9 @@ __getresgid (gid_t *rgid, gid_t *egid, gid_t *sgid)
 
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   return __hurd_fail (err);
 }
diff --git a/sysdeps/mach/hurd/getresuid.c b/sysdeps/mach/hurd/getresuid.c
index 02995db6ed..732e416adc 100644
--- a/sysdeps/mach/hurd/getresuid.c
+++ b/sysdeps/mach/hurd/getresuid.c
@@ -28,6 +28,7 @@ __getresuid (uid_t *ruid, uid_t *euid, uid_t *suid)
 {
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
 
@@ -49,6 +50,9 @@ __getresuid (uid_t *ruid, uid_t *euid, uid_t *suid)
 
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   return __hurd_fail (err);
 }
diff --git a/sysdeps/mach/hurd/getuid.c b/sysdeps/mach/hurd/getuid.c
index fc4a441569..1aadb749e0 100644
--- a/sysdeps/mach/hurd/getuid.c
+++ b/sysdeps/mach/hurd/getuid.c
@@ -27,6 +27,7 @@ __getuid (void)
   error_t err;
   uid_t uid;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
 
@@ -46,6 +47,9 @@ __getuid (void)
 
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (uid == -1 && errno == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   return uid;
 }
diff --git a/sysdeps/mach/hurd/group_member.c b/sysdeps/mach/hurd/group_member.c
index c5256f12a6..72681a8f3b 100644
--- a/sysdeps/mach/hurd/group_member.c
+++ b/sysdeps/mach/hurd/group_member.c
@@ -28,6 +28,7 @@ __group_member (gid_t gid)
   error_t err;
   void *crit;
 
+retry:
   crit = _hurd_critical_section_lock ();
   __mutex_lock (&_hurd_id.lock);
 
@@ -45,6 +46,9 @@ __group_member (gid_t gid)
 
   __mutex_unlock (&_hurd_id.lock);
   _hurd_critical_section_unlock (crit);
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/setegid.c b/sysdeps/mach/hurd/setegid.c
index f0258d3af0..1396e193f2 100644
--- a/sysdeps/mach/hurd/setegid.c
+++ b/sysdeps/mach/hurd/setegid.c
@@ -29,6 +29,7 @@ setegid (gid_t gid)
   auth_t newauth;
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
@@ -55,6 +56,9 @@ setegid (gid_t gid)
     }
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     return __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/seteuid.c b/sysdeps/mach/hurd/seteuid.c
index 637015cc22..97eb22c6b7 100644
--- a/sysdeps/mach/hurd/seteuid.c
+++ b/sysdeps/mach/hurd/seteuid.c
@@ -29,6 +29,7 @@ seteuid (uid_t uid)
   auth_t newauth;
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
@@ -55,6 +56,9 @@ seteuid (uid_t uid)
     }
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     return __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/setgid.c b/sysdeps/mach/hurd/setgid.c
index 6e0672d5e8..c6a64c9423 100644
--- a/sysdeps/mach/hurd/setgid.c
+++ b/sysdeps/mach/hurd/setgid.c
@@ -32,6 +32,7 @@ __setgid (gid_t gid)
   auth_t newauth;
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
@@ -81,6 +82,9 @@ __setgid (gid_t gid)
     }
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     return __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/setgroups.c b/sysdeps/mach/hurd/setgroups.c
index fc78de3fa1..cb6b8996b9 100644
--- a/sysdeps/mach/hurd/setgroups.c
+++ b/sysdeps/mach/hurd/setgroups.c
@@ -34,6 +34,7 @@ setgroups (size_t n, const gid_t *groups)
   for (i = 0; i < n; ++i)
     new[i] = groups[i];
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
@@ -50,6 +51,9 @@ setgroups (size_t n, const gid_t *groups)
     }
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     return __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/setitimer.c b/sysdeps/mach/hurd/setitimer.c
index e23e79a63e..4931644db5 100644
--- a/sysdeps/mach/hurd/setitimer.c
+++ b/sysdeps/mach/hurd/setitimer.c
@@ -339,6 +339,7 @@ __setitimer (enum __itimer_which which, const struct itimerval *new,
 	     struct itimerval *old)
 {
   void *crit;
+  int ret;
 
   switch (which)
     {
@@ -353,9 +354,15 @@ __setitimer (enum __itimer_which which, const struct itimerval *new,
       break;
     }
 
+retry:
   crit = _hurd_critical_section_lock ();
   __spin_lock (&_hurd_itimer_lock);
-  return setitimer_locked (new, old, crit, 0);
+  ret = setitimer_locked (new, old, crit, 0);
+  if (ret == -1 && errno == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
+
+  return ret;
 }
 
 static void
diff --git a/sysdeps/mach/hurd/setregid.c b/sysdeps/mach/hurd/setregid.c
index 2fce6cf6cf..aad736e11d 100644
--- a/sysdeps/mach/hurd/setregid.c
+++ b/sysdeps/mach/hurd/setregid.c
@@ -28,6 +28,7 @@ __setregid (gid_t rgid, gid_t egid)
   auth_t newauth;
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
@@ -82,6 +83,9 @@ __setregid (gid_t rgid, gid_t egid)
     }
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     return __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/setresgid.c b/sysdeps/mach/hurd/setresgid.c
index 8ccfd93c80..64b6840cc8 100644
--- a/sysdeps/mach/hurd/setresgid.c
+++ b/sysdeps/mach/hurd/setresgid.c
@@ -29,6 +29,7 @@ __setresgid (gid_t rgid, gid_t egid, gid_t sgid)
   auth_t newauth;
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
@@ -110,6 +111,9 @@ __setresgid (gid_t rgid, gid_t egid, gid_t sgid)
     }
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     return __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/setresuid.c b/sysdeps/mach/hurd/setresuid.c
index d16db170c2..53d07cccfb 100644
--- a/sysdeps/mach/hurd/setresuid.c
+++ b/sysdeps/mach/hurd/setresuid.c
@@ -29,6 +29,7 @@ __setresuid (uid_t ruid, uid_t euid, uid_t suid)
   auth_t newauth;
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
@@ -111,6 +112,9 @@ __setresuid (uid_t ruid, uid_t euid, uid_t suid)
 
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     return __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/setreuid.c b/sysdeps/mach/hurd/setreuid.c
index 97328e1e1a..d093ed946c 100644
--- a/sysdeps/mach/hurd/setreuid.c
+++ b/sysdeps/mach/hurd/setreuid.c
@@ -28,6 +28,7 @@ __setreuid (uid_t ruid, uid_t euid)
   auth_t newauth;
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
@@ -82,6 +83,9 @@ __setreuid (uid_t ruid, uid_t euid)
     }
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     return __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/setsid.c b/sysdeps/mach/hurd/setsid.c
index 3861f8f850..698fc9cdcf 100644
--- a/sysdeps/mach/hurd/setsid.c
+++ b/sysdeps/mach/hurd/setsid.c
@@ -32,6 +32,7 @@ __setsid (void)
   error_t err;
   unsigned int stamp;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_dtable_lock);
 
@@ -60,6 +61,9 @@ __setsid (void)
     }
 
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   return err ? __hurd_fail (err) : _hurd_pgrp;
 }
diff --git a/sysdeps/mach/hurd/setuid.c b/sysdeps/mach/hurd/setuid.c
index ede3f014c4..4818357c62 100644
--- a/sysdeps/mach/hurd/setuid.c
+++ b/sysdeps/mach/hurd/setuid.c
@@ -32,6 +32,7 @@ __setuid (uid_t uid)
   auth_t newauth;
   error_t err;
 
+retry:
   HURD_CRITICAL_BEGIN;
   __mutex_lock (&_hurd_id.lock);
   err = _hurd_check_ids ();
@@ -86,6 +87,9 @@ __setuid (uid_t uid)
     }
   __mutex_unlock (&_hurd_id.lock);
   HURD_CRITICAL_END;
+  if (err == EINTR)
+    /* Got a signal while inside an RPC of the critical section, retry again */
+    goto retry;
 
   if (err)
     return __hurd_fail (err);
diff --git a/sysdeps/mach/hurd/spawni.c b/sysdeps/mach/hurd/spawni.c
index 9bc1571c29..b5c92365f2 100644
--- a/sysdeps/mach/hurd/spawni.c
+++ b/sysdeps/mach/hurd/spawni.c
@@ -333,6 +333,7 @@ __spawni (pid_t *pid, const char *file,
 
   ss = _hurd_self_sigstate ();
 
+retry:
   assert (! __spin_lock_locked (&ss->critical_section_lock));
   __spin_lock (&ss->critical_section_lock);
 
@@ -437,7 +438,19 @@ __spawni (pid_t *pid, const char *file,
 						 MACH_PORT_RIGHT_SEND, +1));
 
   if (err)
-    goto out;
+    {
+      _hurd_critical_section_unlock (ss);
+
+      if (err == EINTR)
+	{
+	  /* Got a signal while inside an RPC of the critical section, retry again */
+	  __mach_port_deallocate (__mach_task_self (), auth);
+	  auth = MACH_PORT_NULL;
+	  goto retry;
+	}
+
+      goto out;
+    }
 
   /* Pack up the descriptor table to give the new program.
      These descriptors will need to be reauthenticated below
-- 
cgit 1.4.1