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. > > > + 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
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