From 7957425ef5ab365fc96ea0615f99705581c6dbd8 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Ond=C5=99ej=20Lyson=C4=9Bk?= <olysonek@redhat.com>

Date: Mon, 12 Aug 2019 18:15:36 +0200

Subject: [PATCH] Repeat pututxline() until it succeeds if it fails with EINTR

Since the pututxline() bug rhbz#1749439 is now fixed in glibc in

Fedora and RHEL-8, we can implement a complete solution for the stale

utmp entries issue originally reported as rhbz#1688848.

This patch is a followup to commit 896b3694ca062d7.

Resolves: rhbz#1688852

Resolves: rhbz#1737433

---

 sysdeputil.c | 53 +++++++++++++---------------------------------------

 1 file changed, 13 insertions(+), 40 deletions(-)

diff --git a/sysdeputil.c b/sysdeputil.c

index 4fbcca7..75be680 100644

--- a/sysdeputil.c

+++ b/sysdeputil.c

@@ -1203,7 +1203,7 @@ void

 vsf_insert_uwtmp(const struct mystr* p_user_str,

                  const struct mystr* p_host_str)

 {

-  int attempts;

+  struct utmpx* p_res;

   if (sizeof(s_utent.ut_line) < 16)

   {

@@ -1233,34 +1233,21 @@ vsf_insert_uwtmp(const struct mystr* p_user_str,

   vsf_sysutil_strcpy(s_utent.ut_host, str_getbuf(p_host_str),

                      sizeof(s_utent.ut_host));

   s_utent.ut_tv.tv_sec = vsf_sysutil_get_time_sec();

-  for (attempts = 2; attempts > 0; --attempts)

+  setutxent();

+  do

   {

-    struct utmpx* p_res;

-    setutxent();

     p_res = pututxline(&s_utent);

     /* For now we'll ignore errors other than EINTR and EAGAIN */

-    if (p_res != NULL || (errno != EINTR && errno != EAGAIN))

-    {

-      break;

-    }

-  }

-  if (attempts == 0)

-  {

-    /* This makes us skip pututxline() in vsf_remove_uwtmp() */

-    s_uwtmp_inserted = -1;

-  }

-  else

-  {

-    s_uwtmp_inserted = 1;

-    endutxent();

-  }

+  } while (p_res == NULL && (errno == EINTR || errno == EAGAIN));

+  s_uwtmp_inserted = 1;

+  endutxent();

   updwtmpx(WTMPX_FILE, &s_utent);

 }

 void

 vsf_remove_uwtmp(void)

 {

-  int attempts;

+  struct utmpx* p_res;

   if (!s_uwtmp_inserted)

   {

@@ -1270,27 +1257,13 @@ vsf_remove_uwtmp(void)

   vsf_sysutil_memclr(s_utent.ut_user, sizeof(s_utent.ut_user));

   vsf_sysutil_memclr(s_utent.ut_host, sizeof(s_utent.ut_host));

   s_utent.ut_tv.tv_sec = 0;

-  if (s_uwtmp_inserted == 1)

+  setutxent();

+  do

   {

-    for (attempts = 2; attempts > 0; --attempts)

-    {

-      struct utmpx* p_res;

-      setutxent();

-      p_res = pututxline(&s_utent);

-      /* For now we'll ignore errors other than EINTR and EAGAIN */

-      if (p_res != NULL || (errno != EINTR && errno != EAGAIN))

-      {

-        break;

-      }

-    }

-    if (attempts != 0)

-    {

-      endutxent();

-    }

-  }

-  /* Set s_uwtmp_inserted to 0 regardless of the result of

-   * pututxline() to make sure we won't run this function twice.

-   */

+    p_res = pututxline(&s_utent);

+    /* For now we'll ignore errors other than EINTR and EAGAIN */

+  } while (p_res == NULL && (errno == EINTR || errno == EAGAIN));

+  endutxent();

   s_uwtmp_inserted = 0;

   s_utent.ut_tv.tv_sec = vsf_sysutil_get_time_sec();

   updwtmpx(WTMPX_FILE, &s_utent);

-- 

2.20.1