From 33c412d51c2046470ca2770dfac8d7bf15825f20 Mon Sep 17 00:00:00 2001 From: Mary Strodl Date: Thu, 12 Dec 2024 09:30:59 -0500 Subject: [PATCH] bin/admin-upgrade: add kexec support Adds a new `--kexec` flag to `ostree admin upgrade` which will cause the deployment to be loaded into kexec after the upgrade completes. It is particularly useful in conjunction with the `--reboot` flag to perform a reboot into the new deployment without waiting for the (often slow) firmware initialization to take place. (And in my case, allows me to avoid a normal reboot, which can be unreliable on my hardware). After an image has been loaded (using the `kexec_file_load` syscall), the `systemctl-reboot` command (which is called when the existing `-r` flag is included) will trigger a kexec on the loaded image rather than a normal reboot. From `systemctl(1)`: If a new kernel has been loaded via kexec --load, a kexec will be performed instead of a reboot, unless "SYSTEMCTL_SKIP_AUTO_KEXEC=1" has been set. If a new root file system has been set up on "/run/nextroot/", a soft-reboot will be performed instead of a reboot, unless "SYSTEMCTL_SKIP_AUTO_SOFT_REBOOT=1" has been set. A good in-depth technical explanation of kexec can be found here: https://web.archive.org/web/20090505132901/http://www.ibm.com/developerworks/linux/library/l-kexec.html My implementation uses the `kexec_file_load` syscall rather than the older `kexec_load` syscall, which allows the kernel to verify the signatures of the new kernel. It is supported on Linux 3.17 and newer. I assume this probably won't be an issue, but if it is, it's not that hard to put a preprocessor directive around the kexec stuff to disable it for older kernels. Even RHEL is new enough now to not be an issue :) Closes: #435 --- man/ostree-admin-switch.xml | 16 +++++++ man/ostree-admin-upgrade.xml | 8 ++++ src/libostree/ostree-sysroot-deploy.c | 55 +++++++++++++++++++++++++ src/libostree/ostree-sysroot-upgrader.c | 10 ++++- src/libostree/ostree-sysroot-upgrader.h | 1 + src/libostree/ostree-sysroot.h | 5 +++ src/ostree/ot-admin-builtin-switch.c | 8 +++- src/ostree/ot-admin-builtin-upgrade.c | 8 +++- 8 files changed, 107 insertions(+), 4 deletions(-) diff --git a/man/ostree-admin-switch.xml b/man/ostree-admin-switch.xml index 6795c49b97..12848c9046 100644 --- a/man/ostree-admin-switch.xml +++ b/man/ostree-admin-switch.xml @@ -65,6 +65,22 @@ License along with this library. If not, see . Options + + , + + + Reboot after a successful switch. + + + + + , + + + Load new deployment into kexec after a successful switch. + + + ="STATEROOT" diff --git a/man/ostree-admin-upgrade.xml b/man/ostree-admin-upgrade.xml index ccf7a65bd2..38645af903 100644 --- a/man/ostree-admin-upgrade.xml +++ b/man/ostree-admin-upgrade.xml @@ -111,6 +111,14 @@ License along with this library. If not, see . Reboot after a successful upgrade. + + + , + + + Load new deployment into kexec after a successful upgrade. + + diff --git a/src/libostree/ostree-sysroot-deploy.c b/src/libostree/ostree-sysroot-deploy.c index 953b6523d0..ab77c097ea 100644 --- a/src/libostree/ostree-sysroot-deploy.c +++ b/src/libostree/ostree-sysroot-deploy.c @@ -30,6 +30,7 @@ #include #include #include +#include #ifdef HAVE_LIBMOUNT #include @@ -4265,3 +4266,57 @@ ostree_sysroot_deployment_set_mutable (OstreeSysroot *self, OstreeDeployment *de return TRUE; } + +/** + * ostree_sysroot_deployment_kexec_load + * @self: Sysroot + * @deployment: Deployment to prepare a kexec for + * @cancellable: Cancellable + * @error: Error + * + * Prepare the specified deployment for a kexec. + */ +gboolean +ostree_sysroot_deployment_kexec_load (OstreeSysroot *self, OstreeDeployment *deployment, + GCancellable *cancellable, GError **error) +{ + GLNX_AUTO_PREFIX_ERROR ("Loading kernel into kexec", error); + OstreeBootconfigParser *bootconfig = ostree_deployment_get_bootconfig (deployment); + const char *kargs = ostree_bootconfig_parser_get(bootconfig, "options"); + g_autofree char *deployment_dirpath = ostree_sysroot_get_deployment_dirpath (self, deployment); + glnx_autofd int deployment_dfd = -1; + if (!glnx_opendirat (self->sysroot_fd, deployment_dirpath, FALSE, &deployment_dfd, error)) + return FALSE; + + /* Find the kernel/initramfs in the tree */ + g_autoptr (OstreeKernelLayout) kernel_layout = NULL; + if (!get_kernel_from_tree (self, deployment_dfd, &kernel_layout, cancellable, error)) + return FALSE; + + unsigned long flags = 0; + glnx_autofd int kernel_fd = -1; + glnx_autofd int initrd_fd = -1; + + if (!glnx_openat_rdonly (kernel_layout->boot_dfd, kernel_layout->kernel_srcpath, + TRUE, &kernel_fd, error)) + return FALSE; + + /* initramfs is optional */ + if (kernel_layout->initramfs_srcpath) + { + if (!glnx_openat_rdonly (kernel_layout->boot_dfd, kernel_layout->initramfs_srcpath, + TRUE, &initrd_fd, error)) + { + return FALSE; + } + } + else + { + flags |= KEXEC_FILE_NO_INITRAMFS; + } + + if (syscall (SYS_kexec_file_load, kernel_fd, initrd_fd, strlen (kargs) + 1, kargs, flags)) + return glnx_throw_errno_prefix(error, "kexec_file_load"); + + return TRUE; +} diff --git a/src/libostree/ostree-sysroot-upgrader.c b/src/libostree/ostree-sysroot-upgrader.c index 94654c8668..bff9bde128 100644 --- a/src/libostree/ostree-sysroot-upgrader.c +++ b/src/libostree/ostree-sysroot-upgrader.c @@ -601,6 +601,7 @@ ostree_sysroot_upgrader_deploy (OstreeSysrootUpgrader *self, GCancellable *cance /* Experimental flag to enable staging */ gboolean stage = (self->flags & OSTREE_SYSROOT_UPGRADER_FLAGS_STAGE) > 0 || getenv ("OSTREE_EX_STAGE_DEPLOYMENTS") != NULL; + OstreeSysrootSimpleWriteDeploymentFlags write_deployment_flags = OSTREE_SYSROOT_SIMPLE_WRITE_DEPLOYMENT_FLAGS_NONE; if (stage) { if (!ostree_sysroot_stage_tree (self->sysroot, self->osname, self->new_revision, self->origin, @@ -616,8 +617,13 @@ ostree_sysroot_upgrader_deploy (OstreeSysrootUpgrader *self, GCancellable *cance return FALSE; if (!ostree_sysroot_simple_write_deployment (self->sysroot, self->osname, new_deployment, - self->merge_deployment, 0, cancellable, error)) + self->merge_deployment, write_deployment_flags, cancellable, error)) return FALSE; + + + if ((self->flags & OSTREE_SYSROOT_UPGRADER_FLAGS_KEXEC) > 0) + if (!ostree_sysroot_deployment_kexec_load(self->sysroot, new_deployment, cancellable, error)) + return FALSE; } return TRUE; @@ -635,6 +641,8 @@ ostree_sysroot_upgrader_flags_get_type (void) "OSTREE_SYSROOT_UPGRADER_FLAGS_IGNORE_UNCONFIGURED", "ignore-unconfigured" }, { OSTREE_SYSROOT_UPGRADER_FLAGS_STAGE, "OSTREE_SYSROOT_UPGRADER_FLAGS_STAGE", "stage" }, + { OSTREE_SYSROOT_UPGRADER_FLAGS_KEXEC, "OSTREE_SYSROOT_UPGRADER_FLAGS_KEXEC", + "kexec" }, { 0, NULL, NULL } }; GType g_define_type_id = g_flags_register_static (g_intern_static_string ("OstreeSysrootUpgraderFlags"), values); diff --git a/src/libostree/ostree-sysroot-upgrader.h b/src/libostree/ostree-sysroot-upgrader.h index 5d1e8c2aa5..5e2f5ed8a8 100644 --- a/src/libostree/ostree-sysroot-upgrader.h +++ b/src/libostree/ostree-sysroot-upgrader.h @@ -44,6 +44,7 @@ typedef enum OSTREE_SYSROOT_UPGRADER_FLAGS_NONE = (1 << 0), OSTREE_SYSROOT_UPGRADER_FLAGS_IGNORE_UNCONFIGURED = (1 << 1), OSTREE_SYSROOT_UPGRADER_FLAGS_STAGE = (1 << 2), + OSTREE_SYSROOT_UPGRADER_FLAGS_KEXEC = (1 << 3), } OstreeSysrootUpgraderFlags; _OSTREE_PUBLIC diff --git a/src/libostree/ostree-sysroot.h b/src/libostree/ostree-sysroot.h index 3c23f8dd5a..73c2a408ac 100644 --- a/src/libostree/ostree-sysroot.h +++ b/src/libostree/ostree-sysroot.h @@ -268,4 +268,9 @@ gboolean ostree_sysroot_simple_write_deployment (OstreeSysroot *sysroot, const c OstreeSysrootSimpleWriteDeploymentFlags flags, GCancellable *cancellable, GError **error); +_OSTREE_PUBLIC +gboolean +ostree_sysroot_deployment_kexec_load (OstreeSysroot *self, OstreeDeployment *deployment, + GCancellable *cancellable, GError **error); + G_END_DECLS diff --git a/src/ostree/ot-admin-builtin-switch.c b/src/ostree/ot-admin-builtin-switch.c index 592673639f..c8a5461227 100644 --- a/src/ostree/ot-admin-builtin-switch.c +++ b/src/ostree/ot-admin-builtin-switch.c @@ -29,10 +29,12 @@ #include static gboolean opt_reboot; +static gboolean opt_kexec; static char *opt_osname; static GOptionEntry options[] = { { "reboot", 'r', 0, G_OPTION_ARG_NONE, &opt_reboot, "Reboot after switching trees", NULL }, + { "kexec", 'k', 0, G_OPTION_ARG_NONE, &opt_kexec, "Stage new kernel in kexec", NULL }, { "os", 0, 0, G_OPTION_ARG_STRING, &opt_osname, "Use a different operating system root than the current one", "OSNAME" }, { NULL } }; @@ -56,8 +58,12 @@ ot_admin_builtin_switch (int argc, char **argv, OstreeCommandInvocation *invocat const char *new_provided_refspec = argv[1]; + OstreeSysrootUpgraderFlags flags = OSTREE_SYSROOT_UPGRADER_FLAGS_IGNORE_UNCONFIGURED; + if (opt_kexec) + flags |= OSTREE_SYSROOT_UPGRADER_FLAGS_KEXEC; + g_autoptr (OstreeSysrootUpgrader) upgrader = ostree_sysroot_upgrader_new_for_os_with_flags ( - sysroot, opt_osname, OSTREE_SYSROOT_UPGRADER_FLAGS_IGNORE_UNCONFIGURED, cancellable, error); + sysroot, opt_osname, flags, cancellable, error); if (!upgrader) return FALSE; diff --git a/src/ostree/ot-admin-builtin-upgrade.c b/src/ostree/ot-admin-builtin-upgrade.c index 96b1575995..4c9dbbedf2 100644 --- a/src/ostree/ot-admin-builtin-upgrade.c +++ b/src/ostree/ot-admin-builtin-upgrade.c @@ -31,6 +31,7 @@ #include static gboolean opt_reboot; +static gboolean opt_kexec; static gboolean opt_allow_downgrade; static gboolean opt_pull_only; static gboolean opt_deploy_only; @@ -42,6 +43,7 @@ static GOptionEntry options[] = { { "os", 0, 0, G_OPTION_ARG_STRING, &opt_osname, "Use a different operating system root than the current one", "OSNAME" }, { "reboot", 'r', 0, G_OPTION_ARG_NONE, &opt_reboot, "Reboot after a successful upgrade", NULL }, + { "kexec", 'k', 0, G_OPTION_ARG_NONE, &opt_kexec, "Stage new kernel in kexec", NULL }, { "allow-downgrade", 0, 0, G_OPTION_ARG_NONE, &opt_allow_downgrade, "Permit deployment of chronologically older trees", NULL }, { "override-commit", 0, 0, G_OPTION_ARG_STRING, &opt_override_commit, @@ -72,16 +74,18 @@ ot_admin_builtin_upgrade (int argc, char **argv, OstreeCommandInvocation *invoca "Cannot simultaneously specify --pull-only and --deploy-only"); return FALSE; } - else if (opt_pull_only && opt_reboot) + else if (opt_pull_only && (opt_reboot || opt_kexec)) { g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED, - "Cannot simultaneously specify --pull-only and --reboot"); + "Cannot simultaneously specify --pull-only and --reboot or --kexec"); return FALSE; } OstreeSysrootUpgraderFlags flags = 0; if (opt_stage) flags |= OSTREE_SYSROOT_UPGRADER_FLAGS_STAGE; + if (opt_kexec) + flags |= OSTREE_SYSROOT_UPGRADER_FLAGS_KEXEC; g_autoptr (OstreeSysrootUpgrader) upgrader = ostree_sysroot_upgrader_new_for_os_with_flags ( sysroot, opt_osname, flags, cancellable, error);