commit 772e33411bc730f832f415f93eb3e7c67e4d5488

Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>

Date:   Tue Aug 24 16:15:50 2021 -0300

    Use support_open_dev_null_range io/tst-closefrom, misc/tst-close_range, and posix/tst-spawn5 (BZ #28260)

    It ensures a continuous range of file descriptor and avoid hitting

    the RLIMIT_NOFILE.

    Checked on x86_64-linux-gnu.

    (cherry picked from commit 6b20880b22d1d0fce7e9f506baa6fe2d5c7fcfdc)

diff --git a/io/tst-closefrom.c b/io/tst-closefrom.c

index d4c187073c7280e9..395ec0d894101a47 100644

--- a/io/tst-closefrom.c

+++ b/io/tst-closefrom.c

@@ -24,31 +24,22 @@

 #include <support/check.h>

 #include <support/descriptors.h>

 #include <support/xunistd.h>

+#include <support/support.h>

 #include <array_length.h>

 #define NFDS 100

-static int

-open_multiple_temp_files (void)

-{

-  /* Check if the temporary file descriptor has no no gaps.  */

-  int lowfd = xopen ("/dev/null", O_RDONLY, 0600);

-  for (int i = 1; i <= NFDS; i++)

-    TEST_COMPARE (xopen ("/dev/null", O_RDONLY, 0600), lowfd + i);

-  return lowfd;

-}

-

 static int

 closefrom_test (void)

 {

   struct support_descriptors *descrs = support_descriptors_list ();

-  int lowfd = open_multiple_temp_files ();

+  int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600);

-  const int maximum_fd = lowfd + NFDS;

+  const int maximum_fd = lowfd + NFDS - 1;

   const int half_fd = lowfd + NFDS / 2;

-  const int gap = maximum_fd / 4;

+  const int gap = lowfd + NFDS / 4;

   /* Close half of the descriptors and check result.  */

   closefrom (half_fd);

@@ -58,7 +49,7 @@ closefrom_test (void)

       TEST_COMPARE (fcntl (i, F_GETFL), -1);

       TEST_COMPARE (errno, EBADF);

     }

-  for (int i = 0; i < half_fd; i++)

+  for (int i = lowfd; i < half_fd; i++)

     TEST_VERIFY (fcntl (i, F_GETFL) > -1);

   /* Create some gaps, close up to a threshold, and check result.  */

@@ -74,7 +65,7 @@ closefrom_test (void)

       TEST_COMPARE (fcntl (i, F_GETFL), -1);

       TEST_COMPARE (errno, EBADF);

     }

-  for (int i = 0; i < gap; i++)

+  for (int i = lowfd; i < gap; i++)

     TEST_VERIFY (fcntl (i, F_GETFL) > -1);

   /* Close the remmaining but the last one.  */

diff --git a/posix/tst-spawn5.c b/posix/tst-spawn5.c

index ac6673800464ce72..a95199af6b3b7c9a 100644

--- a/posix/tst-spawn5.c

+++ b/posix/tst-spawn5.c

@@ -47,17 +47,6 @@ static int initial_argv_count;

 #define NFDS 100

-static int

-open_multiple_temp_files (void)

-{

-  /* Check if the temporary file descriptor has no no gaps.  */

-  int lowfd = xopen ("/dev/null", O_RDONLY, 0600);

-  for (int i = 1; i <= NFDS; i++)

-    TEST_COMPARE (xopen ("/dev/null", O_RDONLY, 0600),

-		  lowfd + i);

-  return lowfd;

-}

-

 static int

 parse_fd (const char *str)

 {

@@ -185,7 +174,7 @@ spawn_closefrom_test (posix_spawn_file_actions_t *fa, int lowfd, int highfd,

 static void

 do_test_closefrom (void)

 {

-  int lowfd = open_multiple_temp_files ();

+  int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600);

   const int half_fd = lowfd + NFDS / 2;

   /* Close half of the descriptors and check result.  */

diff --git a/sysdeps/unix/sysv/linux/tst-close_range.c b/sysdeps/unix/sysv/linux/tst-close_range.c

index dccb6189c53fcb90..f5069d1b8a067241 100644

--- a/sysdeps/unix/sysv/linux/tst-close_range.c

+++ b/sysdeps/unix/sysv/linux/tst-close_range.c

@@ -36,23 +36,12 @@

 #define NFDS 100

-static int

-open_multiple_temp_files (void)

-{

-  /* Check if the temporary file descriptor has no no gaps.  */

-  int lowfd = xopen ("/dev/null", O_RDONLY, 0600);

-  for (int i = 1; i <= NFDS; i++)

-    TEST_COMPARE (xopen ("/dev/null", O_RDONLY, 0600),

-		  lowfd + i);

-  return lowfd;

-}

-

 static void

 close_range_test_max_upper_limit (void)

 {

   struct support_descriptors *descrs = support_descriptors_list ();

-  int lowfd = open_multiple_temp_files ();

+  int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600);

   {

     int r = close_range (lowfd, ~0U, 0);

@@ -68,7 +57,7 @@ close_range_test_max_upper_limit (void)

 static void

 close_range_test_common (int lowfd, unsigned int flags)

 {

-  const int maximum_fd = lowfd + NFDS;

+  const int maximum_fd = lowfd + NFDS - 1;

   const int half_fd = lowfd + NFDS / 2;

   const int gap_1 = maximum_fd - 8;

@@ -121,7 +110,7 @@ close_range_test (void)

   struct support_descriptors *descrs = support_descriptors_list ();

   /* Check if the temporary file descriptor has no no gaps.  */

-  int lowfd = open_multiple_temp_files ();

+  int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600);

   close_range_test_common (lowfd, 0);

@@ -146,7 +135,7 @@ close_range_test_subprocess (void)

   struct support_descriptors *descrs = support_descriptors_list ();

   /* Check if the temporary file descriptor has no no gaps.  */

-  int lowfd = open_multiple_temp_files ();

+  int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600);

   struct support_stack stack = support_stack_alloc (4096);

@@ -184,7 +173,7 @@ close_range_unshare_test (void)

   struct support_descriptors *descrs1 = support_descriptors_list ();

   /* Check if the temporary file descriptor has no no gaps.  */

-  int lowfd = open_multiple_temp_files ();

+  int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600);

   struct support_descriptors *descrs2 = support_descriptors_list ();

@@ -200,7 +189,7 @@ close_range_unshare_test (void)

   support_stack_free (&stack);

-  for (int i = 0; i < NFDS; i++)

+  for (int i = lowfd; i < lowfd + NFDS; i++)

     TEST_VERIFY (fcntl (i, F_GETFL) > -1);

   support_descriptors_check (descrs2);

@@ -226,9 +215,9 @@ static void

 close_range_cloexec_test (void)

 {

   /* Check if the temporary file descriptor has no no gaps.  */

-  const int lowfd = open_multiple_temp_files ();

+  int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600);

-  const int maximum_fd = lowfd + NFDS;

+  const int maximum_fd = lowfd + NFDS - 1;

   const int half_fd = lowfd + NFDS / 2;

   const int gap_1 = maximum_fd - 8;

@@ -251,13 +240,13 @@ close_range_cloexec_test (void)

   /* Create some gaps, close up to a threshold, and check result.  */

   static int gap_close[] = { 57, 78, 81, 82, 84, 90 };

   for (int i = 0; i < array_length (gap_close); i++)

-    xclose (gap_close[i]);

+    xclose (lowfd + gap_close[i]);

   TEST_COMPARE (close_range (half_fd + 1, gap_1, CLOSE_RANGE_CLOEXEC), 0);

   for (int i = half_fd + 1; i < gap_1; i++)

     {

       int flags = fcntl (i, F_GETFD);

-      if (is_in_array (gap_close, array_length (gap_close), i))

+      if (is_in_array (gap_close, array_length (gap_close), i - lowfd))

         TEST_COMPARE (flags, -1);

       else

         {