diff options
Diffstat (limited to 'arch/um/os-Linux/process.c')
| -rw-r--r-- | arch/um/os-Linux/process.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c new file mode 100644 index 000000000..3a2a84ab9 --- /dev/null +++ b/arch/um/os-Linux/process.c @@ -0,0 +1,211 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de) + * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <errno.h> +#include <signal.h> +#include <fcntl.h> +#include <limits.h> +#include <linux/futex.h> +#include <sys/mman.h> +#include <sys/ptrace.h> +#include <sys/prctl.h> +#include <sys/wait.h> +#include <asm/unistd.h> +#include <init.h> +#include <longjmp.h> +#include <os.h> +#include <skas/skas.h> + +void os_alarm_process(int pid) +{ + if (pid <= 0) + return; + + kill(pid, SIGALRM); +} + +void os_kill_process(int pid, int reap_child) +{ + if (pid <= 0) + return; + + /* Block signals until child is reaped */ + block_signals(); + + kill(pid, SIGKILL); + if (reap_child) + CATCH_EINTR(waitpid(pid, NULL, __WALL)); + + unblock_signals(); +} + +/* Kill off a ptraced child by all means available. kill it normally first, + * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from + * which it can't exit directly. + */ + +void os_kill_ptraced_process(int pid, int reap_child) +{ + if (pid <= 0) + return; + + /* Block signals until child is reaped */ + block_signals(); + + kill(pid, SIGKILL); + ptrace(PTRACE_KILL, pid); + ptrace(PTRACE_CONT, pid); + if (reap_child) + CATCH_EINTR(waitpid(pid, NULL, __WALL)); + + unblock_signals(); +} + +pid_t os_reap_child(void) +{ + int status; + + /* Try to reap a child */ + return waitpid(-1, &status, WNOHANG); +} + +/* Don't use the glibc version, which caches the result in TLS. It misses some + * syscalls, and also breaks with clone(), which does not unshare the TLS. + */ + +int os_getpid(void) +{ + return syscall(__NR_getpid); +} + +int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len, + int r, int w, int x) +{ + void *loc; + int prot; + + prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) | + (x ? PROT_EXEC : 0); + + loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED, + fd, off); + if (loc == MAP_FAILED) + return -errno; + return 0; +} + +int os_protect_memory(void *addr, unsigned long len, int r, int w, int x) +{ + int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) | + (x ? PROT_EXEC : 0)); + + if (mprotect(addr, len, prot) < 0) + return -errno; + + return 0; +} + +int os_unmap_memory(void *addr, int len) +{ + int err; + + err = munmap(addr, len); + if (err < 0) + return -errno; + return 0; +} + +#ifndef MADV_REMOVE +#define MADV_REMOVE KERNEL_MADV_REMOVE +#endif + +int os_drop_memory(void *addr, int length) +{ + int err; + + err = madvise(addr, length, MADV_REMOVE); + if (err < 0) + err = -errno; + return err; +} + +int __init can_drop_memory(void) +{ + void *addr; + int fd, ok = 0; + + printk(UM_KERN_INFO "Checking host MADV_REMOVE support..."); + fd = create_mem_file(UM_KERN_PAGE_SIZE); + if (fd < 0) { + printk(UM_KERN_ERR "Creating test memory file failed, " + "err = %d\n", -fd); + goto out; + } + + addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE, + MAP_SHARED, fd, 0); + if (addr == MAP_FAILED) { + printk(UM_KERN_ERR "Mapping test memory file failed, " + "err = %d\n", -errno); + goto out_close; + } + + if (madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0) { + printk(UM_KERN_ERR "MADV_REMOVE failed, err = %d\n", -errno); + goto out_unmap; + } + + printk(UM_KERN_CONT "OK\n"); + ok = 1; + +out_unmap: + munmap(addr, UM_KERN_PAGE_SIZE); +out_close: + close(fd); +out: + return ok; +} + +void init_new_thread_signals(void) +{ + set_handler(SIGSEGV); + set_handler(SIGTRAP); + set_handler(SIGFPE); + set_handler(SIGILL); + set_handler(SIGBUS); + signal(SIGHUP, SIG_IGN); + set_handler(SIGIO); + /* We (currently) only use the child reaper IRQ in seccomp mode */ + if (using_seccomp) + set_handler(SIGCHLD); + signal(SIGWINCH, SIG_IGN); +} + +void os_set_pdeathsig(void) +{ + prctl(PR_SET_PDEATHSIG, SIGKILL); +} + +int os_futex_wait(void *uaddr, unsigned int val) +{ + int r; + + CATCH_EINTR(r = syscall(__NR_futex, uaddr, FUTEX_WAIT, val, + NULL, NULL, 0)); + return r < 0 ? -errno : r; +} + +int os_futex_wake(void *uaddr) +{ + int r; + + CATCH_EINTR(r = syscall(__NR_futex, uaddr, FUTEX_WAKE, INT_MAX, + NULL, NULL, 0)); + return r < 0 ? -errno : r; +} |