On Wed, 25 Aug 2021 at 15:15, Michael Hudson-Doyle < michael.hudson@canonical.com> wrote: > Hi, thanks for looking at this. > > On Wed, 25 Aug 2021 at 07:29, Adhemerval Zanella via Libc-alpha < > libc-alpha@sourceware.org> wrote: > >> It ensures a continuous range of file descriptor and avoid hitting >> the RLIMIT_NOFILE. >> >> Checked on x86_64-linux-gnu. >> --- >> io/tst-closefrom.c | 15 +++----------- >> posix/tst-spawn5.c | 13 +----------- >> sysdeps/unix/sysv/linux/tst-close_range.c | 25 +++++++---------------- >> 3 files changed, 11 insertions(+), 42 deletions(-) >> >> diff --git a/io/tst-closefrom.c b/io/tst-closefrom.c >> index d4c187073c..0800e19f3f 100644 >> --- a/io/tst-closefrom.c >> +++ b/io/tst-closefrom.c >> @@ -24,29 +24,20 @@ >> #include >> #include >> #include >> +#include >> >> #include >> >> #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; >> > > There are two for loops in this function that iterate from 0: > > for (int i = 0; i < half_fd; i++) > TEST_VERIFY (fcntl (i, F_GETFL) > -1); > > for (int i = 0; i < gap; i++) > TEST_VERIFY (fcntl (i, F_GETFL) > -1); > > These should both iterate from i = lowfd I think? (And maybe should have > done before this change?) Certainly they fail in the cases this patch is > trying to fix. > > diff --git a/posix/tst-spawn5.c b/posix/tst-spawn5.c >> index ac66738004..a95199af6b 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 dccb6189c5..3548b10363 100644 >> --- a/sysdeps/unix/sysv/linux/tst-close_range.c >> +++ b/sysdeps/unix/sysv/linux/tst-close_range.c >> > > This for look in close_range_unshare_test in this file needs to change too: > > for (int i = 0; i < NFDS; i++) > TEST_VERIFY (fcntl (i, F_GETFL) > -1); > > (presumably to iterate from low_fd to lowfd + NFDS). > > >> @@ -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 (); >> >> @@ -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; >> >> -- >> 2.30.2 >> > > Cheers, > mwh > I'm attaching a patch which when applied on top of this one makes these tests pass my hackish way of reproducing the issue: mwhudson@anduril:~/src/pkg/build-glibc$ bash -c 'exec 40