diff options
Diffstat (limited to 'io')
| -rw-r--r-- | io/Makefile | 3 | ||||
| -rw-r--r-- | io/close_range.c | 44 | ||||
| -rw-r--r-- | io/closefrom.c | 16 | ||||
| -rw-r--r-- | io/tst-close_range.c | 300 |
4 files changed, 355 insertions, 8 deletions
diff --git a/io/Makefile b/io/Makefile index ecf65aba60..83f6ffdb76 100644 --- a/io/Makefile +++ b/io/Makefile @@ -57,7 +57,7 @@ routines := \ utimensat futimens file_change_detection \ fts64-time64 \ ftw64-time64 \ - closefrom + closefrom close_range others := pwd test-srcs := ftwtest ftwtest-time64 @@ -79,6 +79,7 @@ tests := test-utime test-stat test-stat2 test-lfs tst-getcwd \ tst-futimens \ tst-utimensat \ tst-closefrom \ + tst-close_range \ tst-ftw-bz28126 tests-time64 := \ diff --git a/io/close_range.c b/io/close_range.c new file mode 100644 index 0000000000..26a615d8b9 --- /dev/null +++ b/io/close_range.c @@ -0,0 +1,44 @@ +/* Close a range of file descriptors. + Copyright (C) 2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <not-cancel.h> +#include <unistd.h> + +/* Close the file descriptors from FIRST up to LAST, inclusive. */ +int +__close_range (unsigned int first, unsigned int last, + int flags) +{ + if (first > last || flags != 0) + { + __set_errno (EINVAL); + return -1; + } + + int maxfd = __getdtablesize (); + if (maxfd == -1) + return -1; + + for (int i = first; i <= last && i < maxfd; i++) + __close_nocancel_nostatus (i); + + return 0; +} +libc_hidden_def (__close_range) +weak_alias (__close_range, close_range) diff --git a/io/closefrom.c b/io/closefrom.c index 01660a7531..e9167687bc 100644 --- a/io/closefrom.c +++ b/io/closefrom.c @@ -16,19 +16,21 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ +#include <stdbool.h> #include <stdio.h> +#include <sys/param.h> #include <unistd.h> -#include <not-cancel.h> void __closefrom (int lowfd) { - int maxfd = __getdtablesize (); - if (maxfd == -1) - __fortify_fail ("closefrom failed to get the file descriptor table size"); + int l = MAX (0, lowfd); - for (int i = 0; i < maxfd; i++) - if (i >= lowfd) - __close_nocancel_nostatus (i); + int r = __close_range (l, ~0U, 0); + if (r == 0) + return ; + + if (!__closefrom_fallback (l, true)) + __fortify_fail ("closefrom failed to close a file descriptor"); } weak_alias (__closefrom, closefrom) diff --git a/io/tst-close_range.c b/io/tst-close_range.c new file mode 100644 index 0000000000..f05b4ff6ae --- /dev/null +++ b/io/tst-close_range.c @@ -0,0 +1,300 @@ +/* Test for the close_range system call. + Copyright (C) 2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <dirent.h> +#include <errno.h> +#include <fcntl.h> +#include <limits.h> +#include <getopt.h> +#include <signal.h> +#include <stdbool.h> +#include <stdlib.h> +#include <stdint.h> + +#include <array_length.h> +#include <support/capture_subprocess.h> +#include <support/check.h> +#include <support/descriptors.h> +#include <support/support.h> +#include <support/xsched.h> +#include <support/xunistd.h> + +#define NFDS 100 + +static void +close_range_test_max_upper_limit (void) +{ + struct support_descriptors *descrs = support_descriptors_list (); + + int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600); + + { + int r = close_range (lowfd, ~0U, 0); + if (r == -1 && errno == ENOSYS) + FAIL_UNSUPPORTED ("close_range not supported"); + TEST_COMPARE (r, 0); + } + + support_descriptors_check (descrs); + support_descriptors_free (descrs); +} + +static void +close_range_test_common (int lowfd, unsigned int flags) +{ + const int maximum_fd = lowfd + NFDS - 1; + const int half_fd = lowfd + NFDS / 2; + const int gap_1 = maximum_fd - 8; + + /* Close half of the descriptors and check result. */ + TEST_COMPARE (close_range (lowfd, half_fd, flags), 0); + for (int i = lowfd; i <= half_fd; i++) + { + TEST_COMPARE (fcntl (i, F_GETFL), -1); + TEST_COMPARE (errno, EBADF); + } + for (int i = half_fd + 1; i < maximum_fd; i++) + TEST_VERIFY (fcntl (i, F_GETFL) > -1); + + /* Create some gaps, close up to a threshold, and check result. */ + xclose (lowfd + 57); + xclose (lowfd + 78); + xclose (lowfd + 81); + xclose (lowfd + 82); + xclose (lowfd + 84); + xclose (lowfd + 90); + + TEST_COMPARE (close_range (half_fd + 1, gap_1, flags), 0); + for (int i = half_fd + 1; i < gap_1; i++) + { + TEST_COMPARE (fcntl (i, F_GETFL), -1); + TEST_COMPARE (errno, EBADF); + } + for (int i = gap_1 + 1; i < maximum_fd; i++) + TEST_VERIFY (fcntl (i, F_GETFL) > -1); + + /* Close the remaining but the last one. */ + TEST_COMPARE (close_range (gap_1 + 1, maximum_fd - 1, flags), 0); + for (int i = gap_1 + 1; i < maximum_fd - 1; i++) + { + TEST_COMPARE (fcntl (i, F_GETFL), -1); + TEST_COMPARE (errno, EBADF); + } + TEST_VERIFY (fcntl (maximum_fd, F_GETFL) > -1); + + /* Close the last one. */ + TEST_COMPARE (close_range (maximum_fd, maximum_fd, flags), 0); + TEST_COMPARE (fcntl (maximum_fd, F_GETFL), -1); + TEST_COMPARE (errno, EBADF); +} + +/* Basic tests: check if the syscall close ranges with and without gaps. */ +static void +close_range_test (void) +{ + struct support_descriptors *descrs = support_descriptors_list (); + + /* Check if the temporary file descriptor has no no gaps. */ + int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600); + + close_range_test_common (lowfd, 0); + + /* Double check by check the /proc. */ + support_descriptors_check (descrs); + support_descriptors_free (descrs); +} + +#ifdef __linux__ +_Noreturn static int +close_range_test_fn (void *arg) +{ + int lowfd = (int) ((uintptr_t) arg); + close_range_test_common (lowfd, 0); + exit (EXIT_SUCCESS); +} + +/* Check if a clone_range on a subprocess created with CLONE_FILES close + the shared file descriptor table entries in the parent. */ +static void +close_range_test_subprocess (void) +{ + struct support_descriptors *descrs = support_descriptors_list (); + + /* Check if the temporary file descriptor has no no gaps. */ + int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600); + + struct support_stack stack = support_stack_alloc (4096); + + pid_t pid = xclone (close_range_test_fn, (void*) (uintptr_t) lowfd, + stack.stack, stack.size, CLONE_FILES | SIGCHLD); + TEST_VERIFY_EXIT (pid > 0); + int status; + xwaitpid (pid, &status, 0); + TEST_VERIFY (WIFEXITED (status)); + TEST_COMPARE (WEXITSTATUS (status), 0); + + support_stack_free (&stack); + + for (int i = lowfd; i < NFDS; i++) + TEST_VERIFY (fcntl (i, F_GETFL) < 0); + + support_descriptors_check (descrs); + support_descriptors_free (descrs); +} +#endif + + +#ifdef CLOSE_RANGE_UNSHARE +_Noreturn static int +close_range_unshare_test_fn (void *arg) +{ + int lowfd = (int) ((uintptr_t) arg); + close_range_test_common (lowfd, CLOSE_RANGE_UNSHARE); + exit (EXIT_SUCCESS); +} + +/* Check if a close_range with CLOSE_RANGE_UNSHARE issued from a subprocess + created with CLONE_FILES does not close the parent file descriptor list. */ +static void +close_range_unshare_test (void) +{ + struct support_descriptors *descrs1 = support_descriptors_list (); + + /* Check if the temporary file descriptor has no no gaps. */ + int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600); + + struct support_descriptors *descrs2 = support_descriptors_list (); + + struct support_stack stack = support_stack_alloc (4096); + + pid_t pid = xclone (close_range_unshare_test_fn, (void*) (uintptr_t) lowfd, + stack.stack, stack.size, CLONE_FILES | SIGCHLD); + TEST_VERIFY_EXIT (pid > 0); + int status; + xwaitpid (pid, &status, 0); + TEST_VERIFY (WIFEXITED (status)); + TEST_COMPARE (WEXITSTATUS (status), 0); + + support_stack_free (&stack); + + for (int i = lowfd; i < lowfd + NFDS; i++) + TEST_VERIFY (fcntl (i, F_GETFL) > -1); + + support_descriptors_check (descrs2); + support_descriptors_free (descrs2); + + TEST_COMPARE (close_range (lowfd, lowfd + NFDS, 0), 0); + + support_descriptors_check (descrs1); + support_descriptors_free (descrs1); +} +#endif + +static bool +is_in_array (int *arr, size_t len, int fd) +{ + bool r = false; + for (int i = 0; i < len; i++) + if (arr[i] == fd) + return true; + return r; +} + +static void +close_range_cloexec_test (void) +{ + /* Check if the temporary file descriptor has no no gaps. */ + int lowfd = support_open_dev_null_range (NFDS, O_RDONLY, 0600); + + const int maximum_fd = lowfd + NFDS - 1; + const int half_fd = lowfd + NFDS / 2; + const int gap_1 = maximum_fd - 8; + + /* Close half of the descriptors and check result. */ + int r = close_range (lowfd, half_fd, CLOSE_RANGE_CLOEXEC); + if (r == -1 && errno == EINVAL) + { + printf ("%s: CLOSE_RANGE_CLOEXEC not supported\n", __func__); + return; + } + for (int i = lowfd; i <= half_fd; i++) + { + int flags = fcntl (i, F_GETFD); + TEST_VERIFY (flags > -1); + TEST_COMPARE (flags & FD_CLOEXEC, FD_CLOEXEC); + } + for (int i = half_fd + 1; i < maximum_fd; i++) + TEST_VERIFY (fcntl (i, F_GETFL) > -1); + + /* 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 (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 - lowfd)) + TEST_COMPARE (flags, -1); + else + { + TEST_VERIFY (flags > -1); + TEST_COMPARE (flags & FD_CLOEXEC, FD_CLOEXEC); + } + } + for (int i = gap_1 + 1; i < maximum_fd; i++) + TEST_VERIFY (fcntl (i, F_GETFL) > -1); + + /* Close the remaining but the last one. */ + TEST_COMPARE (close_range (gap_1 + 1, maximum_fd - 1, CLOSE_RANGE_CLOEXEC), + 0); + for (int i = gap_1 + 1; i < maximum_fd - 1; i++) + { + int flags = fcntl (i, F_GETFD); + TEST_VERIFY (flags > -1); + TEST_COMPARE (flags & FD_CLOEXEC, FD_CLOEXEC); + } + TEST_VERIFY (fcntl (maximum_fd, F_GETFL) > -1); + + /* Close the last one. */ + TEST_COMPARE (close_range (maximum_fd, maximum_fd, CLOSE_RANGE_CLOEXEC), 0); + { + int flags = fcntl (maximum_fd, F_GETFD); + TEST_VERIFY (flags > -1); + TEST_COMPARE (flags & FD_CLOEXEC, FD_CLOEXEC); + } +} + +static int +do_test (void) +{ + close_range_test_max_upper_limit (); + close_range_test (); +#ifdef __linux__ + close_range_test_subprocess (); +#endif +#ifdef CLOSE_RANGE_UNSHARE + close_range_unshare_test (); +#endif + close_range_cloexec_test (); + + return 0; +} + +#include <support/test-driver.c> |