From bb5c77c4f8a5ea9cb3f6bcf5ca33bab4d85d1d92 Mon Sep 17 00:00:00 2001 From: Michael Tokarev Date: Fri, 1 Sep 2023 13:13:02 +0300 Subject: util/async-teardown.c: move to softmmu/, only build it when system build is requested Signed-off-by: Michael Tokarev Reviewed-by: Eric Blake Message-ID: <20230901101302.3618955-9-mjt@tls.msk.ru> Signed-off-by: Paolo Bonzini --- softmmu/async-teardown.c | 146 +++++++++++++++++++++++++++++++++++++++++++++++ softmmu/meson.build | 1 + util/async-teardown.c | 146 ----------------------------------------------- util/meson.build | 1 - 4 files changed, 147 insertions(+), 147 deletions(-) create mode 100644 softmmu/async-teardown.c delete mode 100644 util/async-teardown.c diff --git a/softmmu/async-teardown.c b/softmmu/async-teardown.c new file mode 100644 index 0000000000..62cdeb0f20 --- /dev/null +++ b/softmmu/async-teardown.c @@ -0,0 +1,146 @@ +/* + * Asynchronous teardown + * + * Copyright IBM, Corp. 2022 + * + * Authors: + * Claudio Imbrenda + * + * This work is licensed under the terms of the GNU GPL, version 2 or (at your + * option) any later version. See the COPYING file in the top-level directory. + * + */ + +#include "qemu/osdep.h" +#include +#include +#include + +#include "qemu/async-teardown.h" + +#ifdef _SC_THREAD_STACK_MIN +#define CLONE_STACK_SIZE sysconf(_SC_THREAD_STACK_MIN) +#else +#define CLONE_STACK_SIZE 16384 +#endif + +static pid_t the_ppid; + +/* + * Close all open file descriptors. + */ +static void close_all_open_fd(void) +{ + struct dirent *de; + int fd, dfd; + DIR *dir; + +#ifdef CONFIG_CLOSE_RANGE + int r = close_range(0, ~0U, 0); + if (!r) { + /* Success, no need to try other ways. */ + return; + } +#endif + + dir = opendir("/proc/self/fd"); + if (!dir) { + /* If /proc is not mounted, there is nothing that can be done. */ + return; + } + /* Avoid closing the directory. */ + dfd = dirfd(dir); + + for (de = readdir(dir); de; de = readdir(dir)) { + fd = atoi(de->d_name); + if (fd != dfd) { + close(fd); + } + } + closedir(dir); +} + +static void hup_handler(int signal) +{ + /* Check every second if this process has been reparented. */ + while (the_ppid == getppid()) { + /* sleep() is safe to use in a signal handler. */ + sleep(1); + } + + /* At this point the parent process has terminated completely. */ + _exit(0); +} + +static int async_teardown_fn(void *arg) +{ + struct sigaction sa = { .sa_handler = hup_handler }; + sigset_t hup_signal; + char name[16]; + + /* Set a meaningful name for this process. */ + snprintf(name, 16, "cleanup/%d", the_ppid); + prctl(PR_SET_NAME, (unsigned long)name); + + /* + * Close all file descriptors that might have been inherited from the + * main qemu process when doing clone, needed to make libvirt happy. + * Not using close_range for increased compatibility with older kernels. + */ + close_all_open_fd(); + + /* Set up a handler for SIGHUP and unblock SIGHUP. */ + sigaction(SIGHUP, &sa, NULL); + sigemptyset(&hup_signal); + sigaddset(&hup_signal, SIGHUP); + sigprocmask(SIG_UNBLOCK, &hup_signal, NULL); + + /* Ask to receive SIGHUP when the parent dies. */ + prctl(PR_SET_PDEATHSIG, SIGHUP); + + /* + * Sleep forever, unless the parent process has already terminated. The + * only interruption can come from the SIGHUP signal, which in normal + * operation is received when the parent process dies. + */ + if (the_ppid == getppid()) { + pause(); + } + + /* At this point the parent process has terminated completely. */ + _exit(0); +} + +/* + * Allocate a new stack of a reasonable size, and return a pointer to its top. + */ +static void *new_stack_for_clone(void) +{ + size_t stack_size = CLONE_STACK_SIZE; + char *stack_ptr; + + /* Allocate a new stack and get a pointer to its top. */ + stack_ptr = qemu_alloc_stack(&stack_size); +#if !defined(HOST_HPPA) + /* The top is at the end of the area, except on HPPA. */ + stack_ptr += stack_size; +#endif + + return stack_ptr; +} + +/* + * Block all signals, start (clone) a new process sharing the address space + * with qemu (CLONE_VM), then restore signals. + */ +void init_async_teardown(void) +{ + sigset_t all_signals, old_signals; + + the_ppid = getpid(); + + sigfillset(&all_signals); + sigprocmask(SIG_BLOCK, &all_signals, &old_signals); + clone(async_teardown_fn, new_stack_for_clone(), CLONE_VM, NULL); + sigprocmask(SIG_SETMASK, &old_signals, NULL); +} diff --git a/softmmu/meson.build b/softmmu/meson.build index ea5603f021..c18b7ad738 100644 --- a/softmmu/meson.build +++ b/softmmu/meson.build @@ -37,3 +37,4 @@ endif system_ss.add(when: seccomp, if_true: files('qemu-seccomp.c')) system_ss.add(when: fdt, if_true: files('device_tree.c')) +system_ss.add(when: 'CONFIG_LINUX', if_true: files('async-teardown.c')) diff --git a/util/async-teardown.c b/util/async-teardown.c deleted file mode 100644 index 62cdeb0f20..0000000000 --- a/util/async-teardown.c +++ /dev/null @@ -1,146 +0,0 @@ -/* - * Asynchronous teardown - * - * Copyright IBM, Corp. 2022 - * - * Authors: - * Claudio Imbrenda - * - * This work is licensed under the terms of the GNU GPL, version 2 or (at your - * option) any later version. See the COPYING file in the top-level directory. - * - */ - -#include "qemu/osdep.h" -#include -#include -#include - -#include "qemu/async-teardown.h" - -#ifdef _SC_THREAD_STACK_MIN -#define CLONE_STACK_SIZE sysconf(_SC_THREAD_STACK_MIN) -#else -#define CLONE_STACK_SIZE 16384 -#endif - -static pid_t the_ppid; - -/* - * Close all open file descriptors. - */ -static void close_all_open_fd(void) -{ - struct dirent *de; - int fd, dfd; - DIR *dir; - -#ifdef CONFIG_CLOSE_RANGE - int r = close_range(0, ~0U, 0); - if (!r) { - /* Success, no need to try other ways. */ - return; - } -#endif - - dir = opendir("/proc/self/fd"); - if (!dir) { - /* If /proc is not mounted, there is nothing that can be done. */ - return; - } - /* Avoid closing the directory. */ - dfd = dirfd(dir); - - for (de = readdir(dir); de; de = readdir(dir)) { - fd = atoi(de->d_name); - if (fd != dfd) { - close(fd); - } - } - closedir(dir); -} - -static void hup_handler(int signal) -{ - /* Check every second if this process has been reparented. */ - while (the_ppid == getppid()) { - /* sleep() is safe to use in a signal handler. */ - sleep(1); - } - - /* At this point the parent process has terminated completely. */ - _exit(0); -} - -static int async_teardown_fn(void *arg) -{ - struct sigaction sa = { .sa_handler = hup_handler }; - sigset_t hup_signal; - char name[16]; - - /* Set a meaningful name for this process. */ - snprintf(name, 16, "cleanup/%d", the_ppid); - prctl(PR_SET_NAME, (unsigned long)name); - - /* - * Close all file descriptors that might have been inherited from the - * main qemu process when doing clone, needed to make libvirt happy. - * Not using close_range for increased compatibility with older kernels. - */ - close_all_open_fd(); - - /* Set up a handler for SIGHUP and unblock SIGHUP. */ - sigaction(SIGHUP, &sa, NULL); - sigemptyset(&hup_signal); - sigaddset(&hup_signal, SIGHUP); - sigprocmask(SIG_UNBLOCK, &hup_signal, NULL); - - /* Ask to receive SIGHUP when the parent dies. */ - prctl(PR_SET_PDEATHSIG, SIGHUP); - - /* - * Sleep forever, unless the parent process has already terminated. The - * only interruption can come from the SIGHUP signal, which in normal - * operation is received when the parent process dies. - */ - if (the_ppid == getppid()) { - pause(); - } - - /* At this point the parent process has terminated completely. */ - _exit(0); -} - -/* - * Allocate a new stack of a reasonable size, and return a pointer to its top. - */ -static void *new_stack_for_clone(void) -{ - size_t stack_size = CLONE_STACK_SIZE; - char *stack_ptr; - - /* Allocate a new stack and get a pointer to its top. */ - stack_ptr = qemu_alloc_stack(&stack_size); -#if !defined(HOST_HPPA) - /* The top is at the end of the area, except on HPPA. */ - stack_ptr += stack_size; -#endif - - return stack_ptr; -} - -/* - * Block all signals, start (clone) a new process sharing the address space - * with qemu (CLONE_VM), then restore signals. - */ -void init_async_teardown(void) -{ - sigset_t all_signals, old_signals; - - the_ppid = getpid(); - - sigfillset(&all_signals); - sigprocmask(SIG_BLOCK, &all_signals, &old_signals); - clone(async_teardown_fn, new_stack_for_clone(), CLONE_VM, NULL); - sigprocmask(SIG_SETMASK, &old_signals, NULL); -} diff --git a/util/meson.build b/util/meson.build index a375160286..c4827fd70a 100644 --- a/util/meson.build +++ b/util/meson.build @@ -3,7 +3,6 @@ util_ss.add(files('thread-context.c'), numa) if not config_host_data.get('CONFIG_ATOMIC64') util_ss.add(files('atomic64.c')) endif -util_ss.add(when: 'CONFIG_LINUX', if_true: files('async-teardown.c')) util_ss.add(when: 'CONFIG_POSIX', if_true: files('aio-posix.c')) util_ss.add(when: 'CONFIG_POSIX', if_true: files('fdmon-poll.c')) if config_host_data.get('CONFIG_EPOLL_CREATE1') -- cgit v1.2.3