diff options
Diffstat (limited to 'arch/um/os-Linux/util.c')
| -rw-r--r-- | arch/um/os-Linux/util.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c new file mode 100644 index 000000000..fc0f2a9de --- /dev/null +++ b/arch/um/os-Linux/util.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) + */ + +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <errno.h> +#include <signal.h> +#include <string.h> +#include <termios.h> +#include <sys/wait.h> +#include <sys/mman.h> +#include <sys/utsname.h> +#include <sys/random.h> +#include <init.h> +#include <os.h> + +void stack_protections(unsigned long address) +{ + if (mprotect((void *) address, UM_THREAD_SIZE, + PROT_READ | PROT_WRITE | PROT_EXEC) < 0) + panic("protecting stack failed, errno = %d", errno); +} + +int raw(int fd) +{ + struct termios tt; + int err; + + CATCH_EINTR(err = tcgetattr(fd, &tt)); + if (err < 0) + return -errno; + + cfmakeraw(&tt); + + CATCH_EINTR(err = tcsetattr(fd, TCSADRAIN, &tt)); + if (err < 0) + return -errno; + + /* + * XXX tcsetattr could have applied only some changes + * (and cfmakeraw() is a set of changes) + */ + return 0; +} + +void setup_machinename(char *machine_out) +{ + struct utsname host; + + uname(&host); +#ifdef UML_CONFIG_UML_X86 +# ifndef UML_CONFIG_64BIT + if (!strcmp(host.machine, "x86_64")) { + strcpy(machine_out, "i686"); + return; + } +# else + if (!strcmp(host.machine, "i686")) { + strcpy(machine_out, "x86_64"); + return; + } +# endif +#endif + strcpy(machine_out, host.machine); +} + +void setup_hostinfo(char *buf, int len) +{ + struct utsname host; + + uname(&host); + snprintf(buf, len, "%s %s %s %s %s", host.sysname, host.nodename, + host.release, host.version, host.machine); +} + +/* + * We cannot use glibc's abort(). It makes use of tgkill() which + * has no effect within UML's kernel threads. + * After that glibc would execute an invalid instruction to kill + * the calling process and UML crashes with SIGSEGV. + */ +static inline void __attribute__ ((noreturn)) uml_abort(void) +{ + sigset_t sig; + + fflush(NULL); + + if (!sigemptyset(&sig) && !sigaddset(&sig, SIGABRT)) + sigprocmask(SIG_UNBLOCK, &sig, 0); + + for (;;) + if (kill(getpid(), SIGABRT) < 0) + exit(127); +} + +ssize_t os_getrandom(void *buf, size_t len, unsigned int flags) +{ + return getrandom(buf, len, flags); +} + +/* + * UML helper threads must not handle SIGWINCH/INT/TERM + */ +void os_fix_helper_signals(void) +{ + signal(SIGWINCH, SIG_IGN); + signal(SIGINT, SIG_DFL); + signal(SIGTERM, SIG_DFL); +} + +void os_dump_core(void) +{ + int pid; + + signal(SIGSEGV, SIG_DFL); + + /* + * We are about to SIGTERM this entire process group to ensure that + * nothing is around to run after the kernel exits. The + * kernel wants to abort, not die through SIGTERM, so we + * ignore it here. + */ + + signal(SIGTERM, SIG_IGN); + kill(0, SIGTERM); + /* + * Most of the other processes associated with this UML are + * likely sTopped, so give them a SIGCONT so they see the + * SIGTERM. + */ + kill(0, SIGCONT); + + /* + * Now, having sent signals to everyone but us, make sure they + * die by ptrace. Processes can survive what's been done to + * them so far - the mechanism I understand is receiving a + * SIGSEGV and segfaulting immediately upon return. There is + * always a SIGSEGV pending, and (I'm guessing) signals are + * processed in numeric order so the SIGTERM (signal 15 vs + * SIGSEGV being signal 11) is never handled. + * + * Run a waitpid loop until we get some kind of error. + * Hopefully, it's ECHILD, but there's not a lot we can do if + * it's something else. Tell os_kill_ptraced_process not to + * wait for the child to report its death because there's + * nothing reasonable to do if that fails. + */ + + while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0) + os_kill_ptraced_process(pid, 0); + + uml_abort(); +} + +void um_early_printk(const char *s, unsigned int n) +{ + printf("%.*s", n, s); +} + +static int quiet_info; + +static int __init quiet_cmd_param(char *str, int *add) +{ + quiet_info = 1; + return 0; +} + +__uml_setup("quiet", quiet_cmd_param, +"quiet\n" +" Turns off information messages during boot.\n\n"); + +void os_info(const char *fmt, ...) +{ + va_list list; + + if (quiet_info) + return; + + va_start(list, fmt); + vfprintf(stderr, fmt, list); + va_end(list); +} + +void os_warn(const char *fmt, ...) +{ + va_list list; + + va_start(list, fmt); + vfprintf(stderr, fmt, list); + va_end(list); +} |