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); + if (access(vmlinuz, R_OK) != 0 || access(initrd, R_OK) != 0) + return -errno; + + 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)); + 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 -- 2.2.1.209.g41e5f3a
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