diff options
Diffstat (limited to 'io')
-rw-r--r-- | io/Makefile | 4 | ||||
-rw-r--r-- | io/Versions | 3 | ||||
-rw-r--r-- | io/closefrom.c | 34 | ||||
-rw-r--r-- | io/tst-closefrom.c | 152 |
4 files changed, 192 insertions, 1 deletions
diff --git a/io/Makefile b/io/Makefile index 1a16990205..ebb7d56d67 100644 --- a/io/Makefile +++ b/io/Makefile @@ -56,7 +56,8 @@ routines := \ sendfile sendfile64 copy_file_range \ utimensat futimens file_change_detection \ fts64-time64 \ - ftw64-time64 + ftw64-time64 \ + closefrom others := pwd test-srcs := ftwtest ftwtest-time64 @@ -77,6 +78,7 @@ tests := test-utime test-stat test-stat2 test-lfs tst-getcwd \ tst-lutimes \ tst-futimens \ tst-utimensat \ + tst-closefrom \ tests-time64 := \ tst-futimens-time64 \ diff --git a/io/Versions b/io/Versions index 88caf76bbc..4e19540885 100644 --- a/io/Versions +++ b/io/Versions @@ -137,6 +137,9 @@ libc { stat; stat64; fstat; fstat64; lstat; lstat64; fstatat; fstatat64; mknod; mknodat; } + GLIBC_2.34 { + closefrom; + } GLIBC_PRIVATE { __libc_fcntl64; __fcntl_nocancel; diff --git a/io/closefrom.c b/io/closefrom.c new file mode 100644 index 0000000000..01660a7531 --- /dev/null +++ b/io/closefrom.c @@ -0,0 +1,34 @@ +/* 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 <stdio.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"); + + for (int i = 0; i < maxfd; i++) + if (i >= lowfd) + __close_nocancel_nostatus (i); +} +weak_alias (__closefrom, closefrom) diff --git a/io/tst-closefrom.c b/io/tst-closefrom.c new file mode 100644 index 0000000000..d4c187073c --- /dev/null +++ b/io/tst-closefrom.c @@ -0,0 +1,152 @@ +/* Smoke test for the closefrom. + 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 <fcntl.h> +#include <sys/resource.h> +#include <unistd.h> + +#include <support/check.h> +#include <support/descriptors.h> +#include <support/xunistd.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 (); + + const int maximum_fd = lowfd + NFDS; + const int half_fd = lowfd + NFDS / 2; + const int gap = maximum_fd / 4; + + /* Close half of the descriptors and check result. */ + closefrom (half_fd); + + for (int i = half_fd; i <= maximum_fd; i++) + { + TEST_COMPARE (fcntl (i, F_GETFL), -1); + TEST_COMPARE (errno, EBADF); + } + for (int i = 0; i < half_fd; i++) + TEST_VERIFY (fcntl (i, F_GETFL) > -1); + + /* Create some gaps, close up to a threshold, and check result. */ + xclose (lowfd + 35); + xclose (lowfd + 38); + xclose (lowfd + 42); + xclose (lowfd + 46); + + /* Close half of the descriptors and check result. */ + closefrom (gap); + for (int i = gap + 1; i < maximum_fd; i++) + { + TEST_COMPARE (fcntl (i, F_GETFL), -1); + TEST_COMPARE (errno, EBADF); + } + for (int i = 0; i < gap; i++) + TEST_VERIFY (fcntl (i, F_GETFL) > -1); + + /* Close the remmaining but the last one. */ + closefrom (lowfd + 1); + for (int i = lowfd + 1; i <= maximum_fd; i++) + { + TEST_COMPARE (fcntl (i, F_GETFL), -1); + TEST_COMPARE (errno, EBADF); + } + TEST_VERIFY (fcntl (lowfd, F_GETFL) > -1); + + /* Close the last one. */ + closefrom (lowfd); + TEST_COMPARE (fcntl (lowfd, F_GETFL), -1); + TEST_COMPARE (errno, EBADF); + + /* Double check by check the /proc. */ + support_descriptors_check (descrs); + support_descriptors_free (descrs); + + return 0; +} + +/* Check if closefrom works even when no new file descriptors can be + created. */ +static int +closefrom_test_file_desc_limit (void) +{ + int max_fd = NFDS; + { + struct rlimit rl; + if (getrlimit (RLIMIT_NOFILE, &rl) == -1) + FAIL_EXIT1 ("getrlimit (RLIMIT_NOFILE): %m"); + + max_fd = (rl.rlim_cur < max_fd ? rl.rlim_cur : max_fd); + rl.rlim_cur = max_fd; + + if (setrlimit (RLIMIT_NOFILE, &rl) == 1) + FAIL_EXIT1 ("setrlimit (RLIMIT_NOFILE): %m"); + } + + /* Exhauste the file descriptor limit. */ + int lowfd = xopen ("/dev/null", O_RDONLY, 0600); + for (;;) + { + int fd = open ("/dev/null", O_RDONLY, 0600); + if (fd == -1) + { + if (errno != EMFILE) + FAIL_EXIT1 ("open: %m"); + break; + } + TEST_VERIFY_EXIT (fd < max_fd); + } + + closefrom (lowfd); + for (int i = lowfd; i < NFDS; i++) + { + TEST_COMPARE (fcntl (i, F_GETFL), -1); + TEST_COMPARE (errno, EBADF); + } + + return 0; +} + +static int +do_test (void) +{ + closefrom_test (); + closefrom_test_file_desc_limit (); + + return 0; +} + +#include <support/test-driver.c> |