diff options
44 files changed, 380 insertions, 2 deletions
@@ -63,6 +63,10 @@ Major new features: * On Linux, the close_range function has been added. It allows efficiently closing a range of file descriptors on recent kernels (version 5.9). +* The function closefrom has been added. It closes all file descriptors + greater than given integer. This function is a GNU extension, although it + also present in other systems. + Deprecated and removed features, and other changes affecting compatibility: * The function pthread_mutex_consistent_np has been deprecated; programs diff --git a/include/unistd.h b/include/unistd.h index 691405a945..114a43128e 100644 --- a/include/unistd.h +++ b/include/unistd.h @@ -158,6 +158,7 @@ extern int __brk (void *__addr) attribute_hidden; extern int __close (int __fd); libc_hidden_proto (__close) extern int __libc_close (int __fd); +extern _Bool __closefrom_fallback (int __lowfd) attribute_hidden; extern ssize_t __read (int __fd, void *__buf, size_t __nbytes); libc_hidden_proto (__read) extern ssize_t __write (int __fd, const void *__buf, size_t __n); 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> diff --git a/manual/llio.texi b/manual/llio.texi index e21a71fdd0..2c59f6badf 100644 --- a/manual/llio.texi +++ b/manual/llio.texi @@ -334,6 +334,16 @@ The kernel does not implement the required functionality. @end table @end deftypefun +@deftypefun void closefrom (int @var{lowfd}) +@standards{GNU, unistd.h} +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} + +The function @code{closefrom} closes all file descriptors larger than or equal +to @var{lowfd} then @var{lowfd}. This function is similar to calling +@code{close} for all open file descriptors not less than @var{lowfd}. + +Already closed file descriptors are ignored. +@end deftypefun @node I/O Primitives @section Input and Output Primitives diff --git a/posix/unistd.h b/posix/unistd.h index 217c6c5363..3dca65732f 100644 --- a/posix/unistd.h +++ b/posix/unistd.h @@ -357,6 +357,12 @@ extern __off64_t lseek64 (int __fd, __off64_t __offset, int __whence) __THROW. */ extern int close (int __fd); +#ifdef __USE_MISC +/* Close all open file descriptors greater than or equal to LOWFD. + Negative LOWFD is clamped to 0. */ +extern void closefrom (int __lowfd) __THROW; +#endif + /* Read NBYTES into BUF from FD. Return the number read, -1 for errors or 0 for EOF. diff --git a/sysdeps/mach/hurd/i386/libc.abilist b/sysdeps/mach/hurd/i386/libc.abilist index fcfe64f26b..475bf2d6e9 100644 --- a/sysdeps/mach/hurd/i386/libc.abilist +++ b/sysdeps/mach/hurd/i386/libc.abilist @@ -2225,6 +2225,7 @@ GLIBC_2.34 _Fork F GLIBC_2.34 __isnanf128 F GLIBC_2.34 __libc_start_main F GLIBC_2.34 _hurd_libc_proc_init F +GLIBC_2.34 closefrom F GLIBC_2.34 dladdr F GLIBC_2.34 dladdr1 F GLIBC_2.34 dlclose F diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index e308711168..d45a16af8b 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -64,7 +64,8 @@ sysdep_routines += adjtimex clone umount umount2 readahead sysctl \ pselect32 \ xstat fxstat lxstat xstat64 fxstat64 lxstat64 \ fxstatat fxstatat64 \ - xmknod xmknodat convert_scm_timestamps + xmknod xmknodat convert_scm_timestamps \ + closefrom_fallback CFLAGS-gethostid.c = -fexceptions CFLAGS-tee.c = -fexceptions -fasynchronous-unwind-tables diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist index 428b23fc65..5d5dc5ae57 100644 --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist @@ -2408,6 +2408,7 @@ GLIBC_2.34 aio_write F GLIBC_2.34 aio_write64 F GLIBC_2.34 call_once F GLIBC_2.34 close_range F +GLIBC_2.34 closefrom F GLIBC_2.34 cnd_broadcast F GLIBC_2.34 cnd_destroy F GLIBC_2.34 cnd_init F diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist index d5c24d09ee..5f863c7d46 100644 --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist @@ -2507,6 +2507,7 @@ GLIBC_2.34 aio_write F GLIBC_2.34 aio_write64 F GLIBC_2.34 call_once F GLIBC_2.34 close_range F +GLIBC_2.34 closefrom F GLIBC_2.34 cnd_broadcast F GLIBC_2.34 cnd_destroy F GLIBC_2.34 cnd_init F diff --git a/sysdeps/unix/sysv/linux/arc/libc.abilist b/sysdeps/unix/sysv/linux/arc/libc.abilist index 6213e42bba..e9349e550f 100644 --- a/sysdeps/unix/sysv/linux/arc/libc.abilist +++ b/sysdeps/unix/sysv/linux/arc/libc.abilist @@ -2167,6 +2167,7 @@ GLIBC_2.34 aio_write F GLIBC_2.34 aio_write64 F GLIBC_2.34 call_once F GLIBC_2.34 close_range F +GLIBC_2.34 closefrom F GLIBC_2.34 cnd_broadcast F GLIBC_2.34 cnd_destroy F GLIBC_2.34 cnd_init F diff --git a/sysdeps/unix/sysv/linux/arm/be/libc.abilist b/sysdeps/unix/sysv/linux/arm/be/libc.abilist index 37c395e4cb..cdfa582b30 100644 --- a/sysdeps/unix/sysv/linux/arm/be/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/be/libc.abilist @@ -301,6 +301,7 @@ GLIBC_2.34 aio_write F GLIBC_2.34 aio_write64 F GLIBC_2.34 call_once F GLIBC_2.34 close_range F +GLIBC_2.34 closefrom F GLIBC_2.34 cnd_broadcast F GLIBC_2.34 cnd_destroy F GLIBC_2.34 cnd_init F diff --git a/sysdeps/unix/sysv/linux/arm/le/libc.abilist |