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[209.132.180.131]) by mx.google.com with ESMTPS id q195si5654084pgq.119.2019.05.21.11.49.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 21 May 2019 11:49:26 -0700 (PDT) Received-SPF: pass (google.com: domain of libc-alpha-return-102169-patch=linaro.org@sourceware.org designates 209.132.180.131 as permitted sender) client-ip=209.132.180.131; Authentication-Results: mx.google.com; dkim=pass header.i=@sourceware.org header.s=default header.b=Lv3Iux6t; dkim=pass header.i=@linaro.org header.s=google header.b=qIkUceau; spf=pass (google.com: domain of libc-alpha-return-102169-patch=linaro.org@sourceware.org designates 209.132.180.131 as permitted sender) smtp.mailfrom="libc-alpha-return-102169-patch=linaro.org@sourceware.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:subject:date:message-id; q=dns; s= default; b=a3vjgFN+0jdvbWzqOzuMxOuKzYcY2FRPJ9PnWxTq15SHTH78R4A/D 69Jw3J15+d6RUVwNDPlP4QGYrbUyfJitSMh225JhohAI/KfoHBsUjsB7LvvOUsqU cyXBe5S7FOJbNq48HUTgeoQz8pxQhKmHI86cglhFWbB8qbkRm3hmGc= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:subject:date:message-id; s=default; bh=LCAvdlCxQsjRr4wslGA0Lykeqxs=; b=Lv3Iux6toQn+HglvQ0KUdQ7B62hs HpRaAuQvG2tdO1nZGM1WrHcLnFtI0zp511vuQNqUON82F7JUK/djtvPFW1CaIXpZ ulRKpTjlNddeC7qNdXaNzBQtpa8oWkQVWv3PibW/1UkXe0wlGD/Rlby6WF2+kZ/v 5NwrWuiJlNfqJl0= Received: (qmail 80890 invoked by alias); 21 May 2019 18:49:16 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 80844 invoked by uid 89); 21 May 2019 18:49:09 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-21.1 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=ham version=3.3.1 spammy=face, asks X-HELO: mail-vk1-f195.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:subject:date:message-id; bh=9IhPIfCrAQfqisN+DFFi/I7Owyd1D4DdZ5c+aWLFNc4=; b=qIkUceauBA71zmc+ovr43IzoBnQF5+q2wARNWRboSKUJHi8Gwc2ALLAhNXFHHoX+ar IsJg3p7puPWVwlR2n+BsbV/Ac2sUldk9RKO0s92Q4kixPLjCLX8eiHA8BLAAQS2EBVr1 BGahga9UDMeW7hFYM+F+Ipk9GMYt58v3IHUfBWn/J2/FkHIgLkiRZahv81DldM8OOsHr xS1SxZzKlDTVCaj9CHdAn0I6QSJm/ZP+aUqYsQy90r7m07HMDlIBDu7QQp8TFS/+F3wb RZAQOuXmaqflOWdaTxT5Shx3JFQ8Mkxp8Zi4u/UfBAXEgpPQv8imymKRx1cWIET6yIAv OECw== Return-Path: From: Adhemerval Zanella To: libc-alpha@sourceware.org Subject: [PATCH] RFC: Add posix_spawn_file_actions_closefrom Date: Tue, 21 May 2019 15:48:59 -0300 Message-Id: <20190521184859.29249-1-adhemerval.zanella@linaro.org> This is WIP patch with an RFC to add the way to close a range of file descriptors on posix_spawn as a file action. The API is similar to the one provided by Solaris11, where the file action causes the all open file descriptors greater than or equal to input on to closed when the new process is spawned. There are some discussions on BZ#10353 [2], although the bug itself asks for a generic solution (similar to the closeall provided by some BSD). The posix_spawn is safe to be implemented by interacting over /proc/self/fd, the Linux spawni does not use CLONE_FILES, so the helper process has its own file descriptor table and any failure (in /proc operation) aborts the process creation and returns an error to the caller. I am aware that this file action might be redundant to the current approach of POSIX in promoting O_CLOEXEC in more interfaces. However O_CLOEXEC is still not the default and for some specific usages, the caller needs to close all possible file descriptors to avoid them leaking. Some examples are CPython (discussed in BZ#10353) and OpenJDK jspawnhelper [3] (where OpenJDK spawns a helper process to exactly closes all file descriptors). Most likely any environment which calls functions that might open file descriptor under the hoods and aim to use posix_spawn might face the same requirement. Regarding implementation, to avoid relying on malloc call on child helper I added an internal opendir that receives a previously allocated buffer. The allocated buffer should be large enough to a sane file descriptor usage, and I think it would be hardly a hotspot (so I think there is little point in increasing the buffer and thus stack usage). The patch is incomplete, most lacking the abifiles. If the idea to indeed add such posix_spawn file action I will resend a complete version. [1] https://docs.oracle.com/cd/E36784_01/html/E36874/posix-spawn-file-actions-addclosefrom-np-3c.html [2] https://sourceware.org/bugzilla/show_bug.cgi?id=10353 [3] https://github.com/openjdk/jdk/blob/master/src/java.base/unix/native/libjava/childproc.c --- include/dirent.h | 6 +- posix/Makefile | 5 +- posix/Versions | 1 + posix/spawn.h | 6 + posix/spawn_faction_addclosefrom.c | 51 +++++++++ posix/spawn_faction_destroy.c | 1 + posix/spawn_int.h | 5 + posix/tst-spawn5.c | 176 +++++++++++++++++++++++++++++ sysdeps/posix/closedir.c | 3 +- sysdeps/posix/dirstream.h | 1 + sysdeps/posix/fdopendir.c | 2 +- sysdeps/posix/opendir.c | 94 +++++++++++---- sysdeps/unix/sysv/linux/spawni.c | 52 ++++++++- 13 files changed, 373 insertions(+), 30 deletions(-) create mode 100644 posix/spawn_faction_addclosefrom.c create mode 100644 posix/tst-spawn5.c -- 2.17.1 diff --git a/include/dirent.h b/include/dirent.h index 400835eefe..7642fdaba0 100644 --- a/include/dirent.h +++ b/include/dirent.h @@ -16,6 +16,8 @@ struct scandir_cancel_struct /* Now define the internal interfaces. */ extern DIR *__opendir (const char *__name) attribute_hidden; +extern DIR *__opendir_inplace (const char *__name, void *buffer, size_t size) + attribute_hidden; extern DIR *__opendirat (int dfd, const char *__name) attribute_hidden; extern DIR *__fdopendir (int __fd) attribute_hidden; extern int __closedir (DIR *__dirp) attribute_hidden; @@ -44,8 +46,8 @@ extern int __alphasort64 (const struct dirent64 **a, const struct dirent64 **b) extern int __versionsort64 (const struct dirent64 **a, const struct dirent64 **b) __attribute_pure__; -extern DIR *__alloc_dir (int fd, bool close_fd, int flags, - const struct stat64 *statp) attribute_hidden; +extern DIR *__alloc_dir (int fd, bool close_fd, const struct stat64 *statp, + void *buffer, size_t size) attribute_hidden; extern __typeof (rewinddir) __rewinddir; extern __typeof (seekdir) __seekdir; extern __typeof (dirfd) __dirfd; diff --git a/posix/Makefile b/posix/Makefile index 8ac6743ad7..1ac41ad85a 100644 --- a/posix/Makefile +++ b/posix/Makefile @@ -57,6 +57,7 @@ routines := \ spawn_faction_init spawn_faction_destroy spawn_faction_addclose \ spawn_faction_addopen spawn_faction_adddup2 spawn_valid_fd \ spawn_faction_addchdir spawn_faction_addfchdir \ + spawn_faction_addclosefrom \ spawnattr_init spawnattr_destroy \ spawnattr_getdefault spawnattr_setdefault \ spawnattr_getflags spawnattr_setflags \ @@ -100,7 +101,8 @@ tests := test-errno tstgetopt testfnm runtests runptests \ tst-posix_fadvise tst-posix_fadvise64 \ tst-sysconf-empty-chroot tst-glob_symlinks tst-fexecve \ tst-glob-tilde test-ssize-max tst-spawn4 bug-regex37 \ - bug-regex38 tst-regcomp-truncated tst-spawn-chdir + bug-regex38 tst-regcomp-truncated tst-spawn-chdir \ + tst-spawn5 tests-internal := bug-regex5 bug-regex20 bug-regex33 \ tst-rfc3484 tst-rfc3484-2 tst-rfc3484-3 \ tst-glob_lstat_compat tst-spawn4-compat @@ -254,6 +256,7 @@ tst-exec-static-ARGS = $(tst-exec-ARGS) tst-execvpe5-ARGS = -- $(host-test-program-cmd) tst-spawn-ARGS = -- $(host-test-program-cmd) tst-spawn-static-ARGS = $(tst-spawn-ARGS) +tst-spawn5-ARGS = -- $(host-test-program-cmd) tst-dir-ARGS = `pwd` `cd $(common-objdir)/$(subdir); pwd` `cd $(common-objdir); pwd` $(objpfx)tst-dir tst-chmod-ARGS = $(objdir) tst-vfork3-ARGS = --test-dir=$(objpfx) diff --git a/posix/Versions b/posix/Versions index 7d06a6d0c0..34fe242072 100644 --- a/posix/Versions +++ b/posix/Versions @@ -144,6 +144,7 @@ libc { GLIBC_2.29 { posix_spawn_file_actions_addchdir_np; posix_spawn_file_actions_addfchdir_np; + posix_spawn_file_actions_addclosefrom_np; } GLIBC_2.30 { } diff --git a/posix/spawn.h b/posix/spawn.h index 471dbea022..095ee67a26 100644 --- a/posix/spawn.h +++ b/posix/spawn.h @@ -213,6 +213,12 @@ extern int posix_spawn_file_actions_addchdir_np (posix_spawn_file_actions_t * extern int posix_spawn_file_actions_addfchdir_np (posix_spawn_file_actions_t *, int __fd) __THROW __nonnull ((1)); + +/* Add an action to close all file descriptor greater than FROM durint + spawn. This affects the subsequent file actions. */ +extern int posix_spawn_file_actions_addclosefrom_np (posix_spawn_file_actions_t *, + int __from); + #endif __END_DECLS diff --git a/posix/spawn_faction_addclosefrom.c b/posix/spawn_faction_addclosefrom.c new file mode 100644 index 0000000000..24e6c62dbc --- /dev/null +++ b/posix/spawn_faction_addclosefrom.c @@ -0,0 +1,51 @@ +/* Add a closefrom to a file action list for posix_spawn. + Copyright (C) 2019 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 + . */ + +#include +#include +#include + +#include "spawn_int.h" + +int +__posix_spawn_file_actions_addclosefrom (posix_spawn_file_actions_t + *file_actions, int from) +{ + struct __spawn_action *rec; + + if (!__spawn_valid_fd (from)) + return EBADF; + + /* Allocate more memory if needed. */ + if (file_actions->__used == file_actions->__allocated + && __posix_spawn_file_actions_realloc (file_actions) != 0) + /* This can only mean we ran out of memory. */ + return ENOMEM; + + /* Add the new value. */ + rec = &file_actions->__actions[file_actions->__used]; + rec->tag = spawn_do_closefrom; + rec->action.closefrom_action.from = from; + + /* Account for the new entry. */ + ++file_actions->__used; + + return 0; +} +weak_alias (__posix_spawn_file_actions_addclosefrom, + posix_spawn_file_actions_addclosefrom_np) diff --git a/posix/spawn_faction_destroy.c b/posix/spawn_faction_destroy.c index 51fab13585..b45d1cd889 100644 --- a/posix/spawn_faction_destroy.c +++ b/posix/spawn_faction_destroy.c @@ -39,6 +39,7 @@ __posix_spawn_file_actions_destroy (posix_spawn_file_actions_t *file_actions) case spawn_do_close: case spawn_do_dup2: case spawn_do_fchdir: + case spawn_do_closefrom: /* No cleanup required. */ break; } diff --git a/posix/spawn_int.h b/posix/spawn_int.h index 93b7597f90..2abefe0f57 100644 --- a/posix/spawn_int.h +++ b/posix/spawn_int.h @@ -32,6 +32,7 @@ struct __spawn_action spawn_do_open, spawn_do_chdir, spawn_do_fchdir, + spawn_do_closefrom } tag; union @@ -60,6 +61,10 @@ struct __spawn_action { int fd; } fchdir_action; + struct + { + int from; + } closefrom_action; } action; }; diff --git a/posix/tst-spawn5.c b/posix/tst-spawn5.c new file mode 100644 index 0000000000..7ed03810e4 --- /dev/null +++ b/posix/tst-spawn5.c @@ -0,0 +1,176 @@ +/* Tests for posix_spawn signal handling. + Copyright (C) 2019 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 + . */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +/* Nonzero if the program gets called via `exec'. */ +static int restart; +#define CMDLINE_OPTIONS \ + { "restart", no_argument, &restart, 1 }, + +/* Number of lingering opened file descriptors to opened and checked on + the spawned process. */ +static const int num_fd_to_open = 10; + +/* Called on process re-execution. */ +static int +handle_restart (int from) +{ + DIR *fds = opendir ("/proc/self/fd"); + if (fds == NULL) + FAIL_EXIT1 ("opendir (\"/proc/self/fd\"): %m"); + + while (true) + { + errno = 0; + struct dirent64 *e = readdir64 (fds); + if (e == NULL) + { + if (errno != 0) + FAIL_EXIT1 ("readdir: %m"); + break; + } + + if (e->d_name[0] == '.') + continue; + + char *endptr; + long int fd = strtol (e->d_name, &endptr, 10); + if (*endptr != '\0' || fd < 0 || fd > INT_MAX) + FAIL_EXIT1 ("readdir: invalid file descriptor name: /proc/self/fd/%s", + e->d_name); + + /* Skip the descriptor which is used to enumerate the + descriptors. */ + if (fd == dirfd (fds)) + continue; + + struct stat64 st; + if (fstat64 (fd, &st) != 0) + FAIL_EXIT1 ("readdir: fstat64 (%ld) failed: %m", fd); + + if (fd >= from) + FAIL_EXIT1 ("error: fd (%ld) greater than from (%d)", fd, from); + } + + closedir (fds); + + return 0; +} + +/* Common argument used for process re-execution. */ +static char *initial_spargv[5]; +static size_t initial_spargv_size; + +/* Re-execute the test process with both '--direct', '--restart', and the + TEST (as integer value) as arguments. */ +static void +reexecute (int fd, const posix_spawn_file_actions_t *fa) +{ + char *spargv[8]; + int i; + + for (i = 0; i < initial_spargv_size; i++) + spargv[i] = initial_spargv[i]; + /* Three digits per byte plus null terminator. */ + char teststr[3 * sizeof (fd) + 1]; + snprintf (teststr, array_length (teststr), "%d", fd); + spargv[i++] = teststr; + spargv[i] = NULL; + TEST_VERIFY (i < 8); + + pid_t pid; + int status; + + TEST_COMPARE (posix_spawn (&pid, spargv[0], fa, NULL, spargv, environ), + 0); + TEST_COMPARE (xwaitpid (pid, &status, 0), pid); + TEST_VERIFY (WIFEXITED (status)); + TEST_VERIFY (!WIFSIGNALED (status)); + TEST_COMPARE (WEXITSTATUS (status), 0); +} + +static void +do_test_closefrom (void) +{ + int from = xopen ("/dev/null", O_WRONLY, 0); + for (int i = 1; i < num_fd_to_open; i++) + xopen ("/dev/null", O_WRONLY, 0); + + posix_spawn_file_actions_t fa; + /* posix_spawn_file_actions_init does not fail. */ + posix_spawn_file_actions_init (&fa); + + TEST_COMPARE (posix_spawn_file_actions_addclosefrom_np (&fa, from), 0); + + reexecute (from, &fa); +} + +static int +do_test (int argc, char *argv[]) +{ + /* We must have one or four parameters left if called initially: + + path for ld.so optional + + "--library-path" optional + + the library path optional + + the application name + + Plus one parameter to indicate which test to execute through + re-execution. + + So for default usage without --enable-hardcoded-path-in-tests, it + will be called initially with 5 arguments and later with 2. For + --enable-hardcoded-path-in-tests it will be called with 2 arguments + regardless. */ + + if (argc != (restart ? 2 : 5) && argc != 2) + FAIL_EXIT1 ("wrong number of arguments (%d)", argc); + + if (restart) + return handle_restart (atoi (argv[1])); + + { + int i; + for (i = 0; i < (argc == 5 ? 4 : 1); i++) + initial_spargv[i] = argv[i + 1]; + initial_spargv[i++] = (char *) "--direct"; + initial_spargv[i++] = (char *) "--restart"; + initial_spargv_size = i; + } + + do_test_closefrom (); + + return 0; +} + +#define TEST_FUNCTION_ARGV do_test +#include diff --git a/sysdeps/posix/closedir.c b/sysdeps/posix/closedir.c index fb7da86218..0e55659485 100644 --- a/sysdeps/posix/closedir.c +++ b/sysdeps/posix/closedir.c @@ -47,7 +47,8 @@ __closedir (DIR *dirp) __libc_lock_fini (dirp->lock); #endif - free ((void *) dirp); + if (dirp->allocated) + free ((void *) dirp); return __close_nocancel (fd); } diff --git a/sysdeps/posix/dirstream.h b/sysdeps/posix/dirstream.h index 109fcc1609..861932abd6 100644 --- a/sysdeps/posix/dirstream.h +++ b/sysdeps/posix/dirstream.h @@ -34,6 +34,7 @@ struct __dirstream __libc_lock_define (, lock) /* Mutex lock for this structure. */ size_t allocation; /* Space allocated for the block. */ + bool allocated; /* Space was allocated by opendir. */ size_t size; /* Total valid data in the block. */ size_t offset; /* Current offset into the block. */ diff --git a/sysdeps/posix/fdopendir.c b/sysdeps/posix/fdopendir.c index 4b4e218115..13fe3f14b1 100644 --- a/sysdeps/posix/fdopendir.c +++ b/sysdeps/posix/fdopendir.c @@ -47,6 +47,6 @@ __fdopendir (int fd) return NULL; } - return __alloc_dir (fd, false, flags, &statbuf); + return __alloc_dir (fd, false, &statbuf, NULL, 0); } weak_alias (__fdopendir, fdopendir) diff --git a/sysdeps/posix/opendir.c b/sysdeps/posix/opendir.c index 8e3ba480b7..b576b3233d 100644 --- a/sysdeps/posix/opendir.c +++ b/sysdeps/posix/opendir.c @@ -21,6 +21,8 @@ #include /* For BUFSIZ. */ #include /* For MIN and MAX. */ +#include + #include /* The st_blksize value of the directory is used as a hint for the @@ -46,27 +48,47 @@ invalid_name (const char *name) return false; } -static DIR * -opendir_tail (int fd) +static bool +opendir_tail_common (int fd, struct stat64 *statbuf) { if (__glibc_unlikely (fd < 0)) - return NULL; + return false; /* Now make sure this really is a directory and nothing changed since the `stat' call. The S_ISDIR check is superfluous if O_DIRECTORY works, but it's cheap and we need the stat call for st_blksize anyway. */ - struct stat64 statbuf; - if (__glibc_unlikely (__fxstat64 (_STAT_VER, fd, &statbuf) < 0)) - goto lose; - if (__glibc_unlikely (! S_ISDIR (statbuf.st_mode))) + if (__glibc_unlikely (__fxstat64 (_STAT_VER, fd, statbuf) < 0)) + { + __close_nocancel_nostatus (fd); + return false; + } + if (__glibc_unlikely (! S_ISDIR (statbuf->st_mode))) { __set_errno (ENOTDIR); - lose: __close_nocancel_nostatus (fd); - return NULL; + return false; } + return true; +} + +static DIR * +opendir_tail (int fd) +{ + struct stat64 statbuf; + if (!opendir_tail_common (fd, &statbuf)) + return NULL; + + return __alloc_dir (fd, true, &statbuf, NULL, 0); +} - return __alloc_dir (fd, true, 0, &statbuf); +static DIR * +opendir_tail_inplace (int fd, void *buffer, size_t size) +{ + struct stat64 statbuf; + if (!opendir_tail_common (fd, &statbuf)) + return NULL; + + return __alloc_dir (fd, true, &statbuf, buffer, size); } @@ -94,7 +116,18 @@ __opendir (const char *name) weak_alias (__opendir, opendir) DIR * -__alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp) +__opendir_inplace (const char *name, void *buffer, size_t size) +{ + if (__glibc_unlikely (invalid_name (name))) + return NULL; + + return opendir_tail_inplace (__open_nocancel (name, opendir_oflags), + buffer, size); +} + +DIR * +__alloc_dir (int fd, bool close_fd, const struct stat64 *statp, + void *buffer, size_t size) { /* We have to set the close-on-exit flag if the user provided the file descriptor. */ @@ -114,31 +147,44 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp) allocation = MIN (MAX ((size_t) statp->st_blksize, default_allocation), MAX_DIR_BUFFER_SIZE); #endif - - DIR *dirp = (DIR *) malloc (sizeof (DIR) + allocation); - if (dirp == NULL) + DIR *dirp; + if (!buffer) { - allocation = small_allocation; - dirp = (DIR *) malloc (sizeof (DIR) + allocation); - + dirp = malloc (sizeof (DIR) + allocation); if (dirp == NULL) - lose: { - if (close_fd) + allocation = small_allocation; + dirp = (DIR *) malloc (sizeof (DIR) + allocation); + + if (dirp == NULL) { - int save_errno = errno; - __close_nocancel_nostatus (fd); - __set_errno (save_errno); + if (close_fd) + lose: + { + int save_errno = errno; + __close_nocancel_nostatus (fd); + __set_errno (save_errno); + } + return NULL; } - return NULL; } + dirp->allocated = true; + dirp->allocation = allocation; + } + else + { + dirp = buffer; + if (allocation < sizeof (struct __dirstream) + + sizeof (struct dirent)) + goto lose; + dirp->allocated = false; + dirp->allocation = size; } dirp->fd = fd; #if IS_IN (libc) __libc_lock_init (dirp->lock); #endif - dirp->allocation = allocation; dirp->size = 0; dirp->offset = 0; dirp->filepos = 0; diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c index c1abf3f960..fe0ff95825 100644 --- a/sysdeps/unix/sysv/linux/spawni.c +++ b/sysdeps/unix/sysv/linux/spawni.c @@ -31,6 +31,7 @@ #include #include #include +#include #include "spawn_int.h" /* The Linux implementation of posix_spawn{p} uses the clone syscall directly @@ -114,6 +115,46 @@ maybe_script_execute (struct posix_spawn_args *args) } } +/* Close all file descriptor up to FROM by interacting /proc/self/fd. + Any failure should */ +static bool +spawn_closefrom (int from) +{ + /* Increasing the buffer size incurs in less getdents syscalls from + readdir, however it would require more stack size to be allocated + on __spawnix. */ + char buffer[sizeof (struct __dirstream) + 2 * sizeof (struct dirent)]; + + DIR *dp; + if ((dp = __opendir_inplace ("/proc/self/fd", buffer, sizeof buffer)) + == NULL) + return false; + + bool ret = true; + struct dirent *dirp; + while ((dirp = __readdir (dp)) != NULL) + { + if (dirp->d_name[0] == '.') + continue; + + char *endptr; + long int fd = strtol (dirp->d_name, &endptr, 10); + if (*endptr != '\0' || fd < 0 || fd > INT_MAX) + { + ret = false; + break; + } + + if (fd == dirfd (dp) || fd < from) + continue; + + __close (fd); + } + __closedir (dp); + + return ret; +} + /* Function used in the clone call to setup the signals mask, posix_spawn attributes, and file actions. It run on its own stack (provided by the posix_spawn call). */ @@ -280,6 +321,11 @@ __spawni_child (void *arguments) if (__fchdir (action->action.fchdir_action.fd) != 0) goto fail; break; + + case spawn_do_closefrom: + if (!spawn_closefrom (action->action.closefrom_action.from)) + goto fail; + break; } } } @@ -339,8 +385,12 @@ __spawnix (pid_t * pid, const char *file, int prot = (PROT_READ | PROT_WRITE | ((GL (dl_stack_flags) & PF_X) ? PROT_EXEC : 0)); + /* The __spawni_child uses about 768 on x86_64 (including the stack for + opendir_inplace), so add some extra space. */ + const size_t stack_slack = 1024; + /* Add a slack area for child's stack. */ - size_t argv_size = (argc * sizeof (void *)) + 512; + size_t argv_size = (argc * sizeof (void *)) + stack_slack; /* We need at least a few pages in case the compiler's stack checking is enabled. In some configs, it is known to use at least 24KiB. We use 32KiB to be "safe" from anything the compiler might do. Besides, the