mirror of
https://github.com/troglobit/finit.git
synced 2026-10-01 05:22:48 +07:00
Joachim Wiberg
a215747355
Define __NR_clone3 (435) ourselves when not provided by the toolchain headers. The syscall number is stable kernel ABI and the same on all architectures since Linux 5.3. The existing runtime fallback to fork() handles older kernels that don't support the syscall. Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
97 lines
2.8 KiB
C
97 lines
2.8 KiB
C
/* Portable clone3() wrapper with fallback to fork()
|
|
*
|
|
* Copyright (c) 2025 Joachim Wiberg <troglobit@gmail.com>
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
* THE SOFTWARE.
|
|
*/
|
|
|
|
#include "config.h"
|
|
|
|
#include <errno.h>
|
|
#include <sched.h>
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
#include <string.h>
|
|
#include <sys/syscall.h>
|
|
#include <sys/types.h>
|
|
#include <sys/wait.h>
|
|
#include <unistd.h>
|
|
|
|
#include "clone3.h"
|
|
#include "finit.h"
|
|
#include "log.h"
|
|
|
|
/* clone3() was added in Linux 5.3, syscall number 435 on all archs */
|
|
#ifndef __NR_clone3
|
|
#define __NR_clone3 435
|
|
#endif
|
|
|
|
/* Clone3 flags from linux/sched.h */
|
|
#ifndef CLONE_INTO_CGROUP
|
|
#define CLONE_INTO_CGROUP 0x200000000ULL
|
|
#endif
|
|
|
|
/* Linux kernel struct clone_args for clone3() syscall */
|
|
struct clone3_args {
|
|
uint64_t flags; /* Flags bit mask */
|
|
uint64_t pidfd; /* File descriptor for PID */
|
|
uint64_t child_tid; /* Child TID */
|
|
uint64_t parent_tid; /* Parent TID */
|
|
uint64_t exit_signal; /* Signal to deliver on exit */
|
|
uint64_t stack; /* Stack address */
|
|
uint64_t stack_size; /* Stack size */
|
|
uint64_t tls; /* TLS descriptor */
|
|
uint64_t set_tid; /* Set PID */
|
|
uint64_t set_tid_size; /* Number of set_tid entries */
|
|
uint64_t cgroup; /* Cgroup file descriptor */
|
|
} __attribute__((aligned(8)));
|
|
|
|
static int use_clone3 = 1;
|
|
|
|
int has_clone3(void)
|
|
{
|
|
return use_clone3 == 1;
|
|
}
|
|
|
|
pid_t call_clone3(uint64_t flags, int cgroup_fd)
|
|
{
|
|
struct clone3_args cl = {
|
|
.flags = flags,
|
|
.exit_signal = SIGCHLD,
|
|
};
|
|
pid_t pid;
|
|
|
|
if (!use_clone3)
|
|
goto fallback;
|
|
|
|
if (cgroup_fd >= 0) {
|
|
cl.flags |= CLONE_INTO_CGROUP;
|
|
cl.cgroup = cgroup_fd;
|
|
}
|
|
|
|
pid = syscall(__NR_clone3, &cl, sizeof(cl));
|
|
if (pid != -1)
|
|
return pid;
|
|
|
|
logit(LOG_WARNING, "clone3() failed, falling back to fork(): %s", strerror(errno));
|
|
use_clone3 = 0;
|
|
fallback:
|
|
return fork();
|
|
}
|