On Tue, Feb 17, 2015 at 4:34 PM, Shawn Landden <sh...@churchofgit.com> wrote:
> On Tue, Feb 17, 2015 at 7:00 AM, Zbigniew Jędrzejewski-Szmek < > zbys...@in.waw.pl> wrote: > >> On Mon, Feb 16, 2015 at 07:53:47PM -0800, Shawn Landden wrote: >> > On Mon, Feb 16, 2015 at 5:08 AM, Lennart Poettering < >> lenn...@poettering.net> >> > wrote: >> > >> > > On Fri, 13.02.15 14:18, Shawn Landden (sh...@churchofgit.com) wrote: >> > > >> > > > Still use helper when Xen Dom0, to avoid duplicating some hairy >> > > > code. >> > > >> > > Hmm, what precisely does the helper do on xen? >> > > >> > > > So we don't have any logic to load kexec kernels? >> > > >> > > Currently we don't. >> > > >> > > My hope though was that we can make the whole kexec thing work without >> > > having kexec-tools installed. With the new kernel syscall for loading >> > > the kernel we should be able to implement this all without any other >> > > tools. >> > > >> > > Ideally we'd not use any external tools anymore, not even in the Xen >> > > case, hence I am curious what precisely the special hookup for Xen is >> > > here...? >> > > >> > > Lennart >> > > >> > > >> > >> https://git.kernel.org/cgit/utils/kernel/kexec/kexec-tools.git/tree/kexec/kexec-xen.c >> > >> > I've attached my patch. >> > I'm having a problem with kexec_file_load() returning ENOMEM that I >> havn't >> > resolved. >> > >> > > -- >> > > Lennart Poettering, Red Hat >> > > _______________________________________________ >> > > systemd-devel mailing list >> > > systemd-devel@lists.freedesktop.org >> > > http://lists.freedesktop.org/mailman/listinfo/systemd-devel >> > > >> > >> > >> > >> > -- >> > Shawn Landden >> >> > From d5446e324143f55e67bc2defe1c78a4ea4201142 Mon Sep 17 00:00:00 2001 >> > From: Shawn Landden <sh...@churchofgit.com> >> > Date: Fri, 13 Feb 2015 13:48:07 -0800 >> > Subject: [PATCH] shutdown: avoid calling `kexec` binary unnessecarily >> > >> > Still use helper when Xen Dom0, to avoid duplicating some hairy code. >> > So we don't have any logic to load kexec kernels? >> > --- >> > TODO | 3 -- >> > src/core/shutdown.c | 121 >> ++++++++++++++++++++++++++++++++++++++++++++++----- >> > src/shared/missing.h | 7 +++ >> > 3 files changed, 116 insertions(+), 15 deletions(-) >> > >> > diff --git a/TODO b/TODO >> > index 255a4f2..d914d2c 100644 >> > --- a/TODO >> > +++ b/TODO >> > @@ -90,9 +90,6 @@ Features: >> > * maybe introduce WantsMountsFor=? Usecase: >> > >> http://lists.freedesktop.org/archives/systemd-devel/2015-January/027729.html >> > >> > -* rework kexec logic to use new kexec_file_load() syscall, so that we >> > - don't have to call kexec tool anymore. >> > - >> > * The udev blkid built-in should expose a property that reflects >> > whether media was sensed in USB CF/SD card readers. This should then >> > be used to control SYSTEMD_READY=1/0 so that USB card readers aren't >> > diff --git a/src/core/shutdown.c b/src/core/shutdown.c >> > index 71f001a..14febf3 100644 >> > --- a/src/core/shutdown.c >> > +++ b/src/core/shutdown.c >> > @@ -19,6 +19,7 @@ >> > along with systemd; If not, see <http://www.gnu.org/licenses/>. >> > ***/ >> > >> > +#include <ctype.h> >> > #include <sys/mman.h> >> > #include <sys/types.h> >> > #include <sys/reboot.h> >> > @@ -27,6 +28,7 @@ >> > #include <sys/stat.h> >> > #include <sys/mount.h> >> > #include <sys/syscall.h> >> > +#include <sys/utsname.h> >> > #include <fcntl.h> >> > #include <dirent.h> >> > #include <errno.h> >> > @@ -138,6 +140,35 @@ static int parse_argv(int argc, char *argv[]) { >> > return 0; >> > } >> > >> > +/* >> > + * Remove parameter from a kernel command line. Helper function for >> kexec. >> > + * (copied from kexec-tools) >> > + */ >> > +static void remove_parameter(char *line, const char *param_name) { >> > + char *start, *end; >> > + >> > + start = strstr(line, param_name); >> > + >> > + /* parameter not found */ >> > + if (!start) >> > + return; >> > + >> > + /* >> > + * check if that's really the start of a parameter and not in >> > + * the middle of the word >> > + */ >> > + if (start != line && !isspace(*(start-1))) >> > + return; >> > + >> > + end = strstr(start, " "); >> > + if (!end) >> > + *start = 0; >> > + else { >> > + memmove(start, end+1, strlen(end)); >> > + *(end + strlen(end)) = 0; >> > + } >> > +} >> > + >> > static int switch_root_initramfs(void) { >> > if (mount("/run/initramfs", "/run/initramfs", NULL, MS_BIND, >> NULL) < 0) >> > return log_error_errno(errno, "Failed to mount bind >> /run/initramfs on /run/initramfs: %m"); >> > @@ -152,6 +183,57 @@ static int switch_root_initramfs(void) { >> > return switch_root("/run/initramfs", "/oldroot", false, >> MS_BIND); >> > } >> > >> > +static int kernel_load(bool overwrite) { >> > + int r = -ENOTSUP; >> > + >> > +/* only x86_64 and x32 in 3.18 */ >> > +#ifdef __NR_kexec_file_load >> > + /* If uses has no already loaded a kexec kernel assume >> they >> > + * want the same one they are currently running. */ >> > + if (!overwrite && !kexec_loaded()) { >> > + struct utsname u; >> > + _cleanup_free_ char *vmlinuz = NULL, *initrd = >> NULL, *cmdline = NULL; >> > + _cleanup_close_ int vmlinuz_fd = -1, initrd_fd >> = -1; >> > + >> > + r = uname(&u); >> > + if (r < 0) >> > + return -errno; >> > + >> > + vmlinuz = malloc(strlen("/boot/vmlinuz-") + >> strlen(u.release) + 1); >> > + initrd = malloc(strlen("/boot/initrd.img-") + >> strlen(u.release) + 1); >> > + if (!vmlinuz || !initrd) >> > + return -ENOMEM; >> > + >> > + r = read_one_line_file("/proc/cmdline", >> &cmdline); >> > + if (r < 0) >> > + return r; >> > + >> > + strcpy(stpcpy(vmlinuz, "/boot/vmlinuz-"), >> u.release); >> > + strcpy(stpcpy(initrd, "/boot/initrd.img-"), >> u.release); >> Wouldn't a simple strjoina work just as well here? >> >> We also have the boot loader specification. We really need to follow >> it here, and look for kernels in any place where we would install them. >> So this scheme most likely would have to be more comples. >> >> > + if (access(vmlinuz, R_OK) != 0 || >> access(initrd, R_OK) != 0) >> > + return -errno; >> No need to to do this check, the open()s below work just as well. >> >> > + vmlinuz_fd = open(vmlinuz, O_RDONLY); >> > + if (vmlinuz_fd < 0) >> > + return -errno; >> > + >> > + initrd_fd = open(initrd, O_RDONLY); >> > + if (initrd_fd < 0) >> > + return -errno; >> > + >> > + /* clean up cmdline like kexec-tools does */ >> > + remove_parameter(cmdline, "BOOT_IMAGE"); >> > + >> > + log_info("kexec: kexec -l %s --initrd=%s >> --command-line=%s", vmlinuz, initrd, cmdline); >> > + >> > + r = syscall(__NR_kexec_file_load, vmlinuz_fd, >> initrd_fd, cmdline, strlen(cmdline), 0); >> > + if (r < 0) >> > + return -errno; >> > + } else >> > + r = 0; >> > +#endif >> > + return r; >> > +} >> > >> > int main(int argc, char *argv[]) { >> > bool need_umount, need_swapoff, need_loop_detach, >> need_dm_detach; >> > @@ -175,11 +257,13 @@ int main(int argc, char *argv[]) { >> > >> > umask(0022); >> > >> > - if (getpid() != 1) { >> > + /*if (getpid() != 1) { >> > log_error("Not executed by init (PID 1)."); >> > r = -EPERM; >> > goto error; >> > - } >> > + }*/ >> > + >> > + in_container = detect_container(NULL) > 0; >> > >> > if (streq(arg_verb, "reboot")) >> > cmd = RB_AUTOBOOT; >> > @@ -187,9 +271,19 @@ int main(int argc, char *argv[]) { >> > cmd = RB_POWER_OFF; >> > else if (streq(arg_verb, "halt")) >> > cmd = RB_HALT_SYSTEM; >> > - else if (streq(arg_verb, "kexec")) >> > - cmd = LINUX_REBOOT_CMD_KEXEC; >> > - else { >> > + else if (streq(arg_verb, "kexec")) { >> > + if (in_container) { >> > + log_warning("Can't kexec from container. >> Rebooting…"); >> > + cmd = RB_AUTOBOOT; >> > + } else { >> > + r = kernel_load(false); >> > + if (r < 0) { >> > + log_warning("Failed to load kernel: >> %s. Rebooting…", strerror(-r)); >> >> I think this should be changed too. I'd very much prefer to get an error >> if kexec fails. >> Maybe we could add a parameter like --always-reboot to reboot as a >> fallback if the >> kenrel cannot be loaded. >> > This is not the user API, that is systemctl. This binary is executed only > by pid 1. > This _IS_ pid 1, after the main pid 1 quits by executing this shutdown binary. > >> > + cmd = RB_AUTOBOOT; >> > + } else >> > + cmd = LINUX_REBOOT_CMD_KEXEC; >> > + } >> > + } else { >> > r = -EINVAL; >> > log_error("Unknown action '%s'.", arg_verb); >> > goto error; >> > @@ -208,8 +302,6 @@ int main(int argc, char *argv[]) { >> > log_info("Sending SIGKILL to remaining processes..."); >> > broadcast_signal(SIGKILL, true, false); >> > >> > - in_container = detect_container(NULL) > 0; >> > - >> > need_umount = !in_container; >> > need_swapoff = !in_container; >> > need_loop_detach = !in_container; >> > @@ -349,11 +441,14 @@ int main(int argc, char *argv[]) { >> > >> > case LINUX_REBOOT_CMD_KEXEC: >> > >> > - if (!in_container) { >> > - /* We cheat and exec kexec to avoid doing all >> its work */ >> > - pid_t pid; >> > + log_info("Rebooting with kexec."); >> > >> > - log_info("Rebooting with kexec."); >> > + /* kexec-tools has a bunch of special code to make Xen >> Dom0 work, >> > + * otherwise it is only doing stuff we have already >> done. >> > + * This is true for Dom0 and DomU but we only get Dom0 >> > + * because of the !in_container check */ >> > + if (access("/proc/xen", F_OK) == 0) { >> > + pid_t pid; >> > >> > pid = fork(); >> > if (pid < 0) >> > @@ -370,7 +465,9 @@ int main(int argc, char *argv[]) { >> > _exit(EXIT_FAILURE); >> > } else >> > wait_for_terminate_and_warn("kexec", >> pid, true); >> > - } >> > + >> > + } else >> > + reboot(cmd); >> > >> > cmd = RB_AUTOBOOT; >> > /* Fall through */ >> > diff --git a/src/shared/missing.h b/src/shared/missing.h >> > index b33a70c..efd650a 100644 >> > --- a/src/shared/missing.h >> > +++ b/src/shared/missing.h >> > @@ -763,3 +763,10 @@ static inline int kcmp(pid_t pid1, pid_t pid2, int >> type, unsigned long idx1, uns >> > #ifndef KCMP_FILE >> > #define KCMP_FILE 0 >> > #endif >> > + >> > +/* v3.17 */ >> > +#ifndef __NR_kexec_file_load >> > +#ifdef __x86_64__ >> > +#define __NR_kexec_file_load 320 >> > +#endif >> > +#endif >> > -- >> >> Zbyszek >> _______________________________________________ >> systemd-devel mailing list >> systemd-devel@lists.freedesktop.org >> http://lists.freedesktop.org/mailman/listinfo/systemd-devel >> > > > > -- > Shawn Landden > -- Shawn Landden
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