[PATCH v1 2/2] kexec: Support -S paramter to return whether the kexec payload is loaded.
Pratyush Anand
panand at redhat.com
Mon Nov 14 20:44:13 PST 2016
On Tuesday 15 November 2016 03:42 AM, Konrad Rzeszutek Wilk wrote:
> Instead of the scripts having to poke at various fields we can
> provide that functionality via the -S parameter.
>
> Returns 0 if the payload is loaded. Can be used in combination
> with -l or -p to get the state of the proper kexec image.
>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
> ---
> v0: First version (internal product).
> v1: Posted on kexec mailing list. Changed -s to -S
>
> CC: kexec at lists.infradead.org
> CC: xen-devel at lists.xenproject.org
> CC: Daniel Kiper <daniel.kiper at oracle.com>
> ---
> kexec/kexec-xen.c | 20 ++++++++++++++++++
> kexec/kexec.8 | 5 +++++
> kexec/kexec.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
> kexec/kexec.h | 5 ++++-
> 4 files changed, 85 insertions(+), 6 deletions(-)
>
> diff --git a/kexec/kexec-xen.c b/kexec/kexec-xen.c
> index 24a4191..5a1e9d2 100644
> --- a/kexec/kexec-xen.c
> +++ b/kexec/kexec-xen.c
> @@ -105,6 +105,26 @@ int xen_kexec_unload(uint64_t kexec_flags)
> return ret;
> }
>
> +int xen_kexec_status(uint64_t kexec_flags)
> +{
> + xc_interface *xch;
> + uint8_t type;
> + int ret;
> +
> + xch = xc_interface_open(NULL, NULL, 0);
> + if (!xch)
> + return -1;
> +
> + type = (kexec_flags & KEXEC_ON_CRASH) ? KEXEC_TYPE_CRASH
> + : KEXEC_TYPE_DEFAULT;
> +
> + ret = xc_kexec_status(xch, type);
> +
> + xc_interface_close(xch);
> +
> + return ret;
> +}
> +
> void xen_kexec_exec(void)
> {
> xc_interface *xch;
> diff --git a/kexec/kexec.8 b/kexec/kexec.8
> index 4d0c1d1..02f4ccf 100644
> --- a/kexec/kexec.8
> +++ b/kexec/kexec.8
> @@ -107,6 +107,11 @@ command:
> .B \-d\ (\-\-debug)
> Enable debugging messages.
> .TP
> +.B \-D\ (\-\-status)
> +Return 0 if the type (by default crash) is loaded. Can be used in conjuction
> +with -l or -p to toggle the type. Note it will
> +.BR not\ load\ the\ kernel.
Better to specify that it will supersede all other options and will
neither load nor unload the kernel.
> +.TP
> .B \-e\ (\-\-exec)
> Run the currently loaded kernel. Note that it will reboot into the loaded kernel without calling shutdown(8).
> .TP
> diff --git a/kexec/kexec.c b/kexec/kexec.c
> index 500e5a9..bc72688 100644
> --- a/kexec/kexec.c
> +++ b/kexec/kexec.c
> @@ -855,6 +855,32 @@ static int k_unload (unsigned long kexec_flags)
> return result;
> }
>
> +static int kexec_loaded(void);
> +static int __kexec_loaded(const char *f);
> +
Why not to define k_status below kexec_loaded() so that you do not need
above prototypes.
> +static int k_status(unsigned long kexec_flags)
> +{
> + int result;
> + long native_arch;
> +
> + /* set the arch */
> + native_arch = physical_arch();
> + if (native_arch < 0) {
> + return -1;
> + }
> + kexec_flags |= native_arch;
> +
> + if (xen_present())
> + result = xen_kexec_status(kexec_flags);
> + else {
> + if (kexec_flags & KEXEC_ON_CRASH)
> + result = __kexec_loaded("/sys/kernel/kexec_crash_loaded");
> + else
> + result = kexec_loaded();
> + }
> + return result;
> +}
> +
> /*
> * Start a reboot.
> */
> @@ -890,8 +916,6 @@ static int my_exec(void)
> return -1;
> }
>
> -static int kexec_loaded(void);
> -
> static int load_jump_back_helper_image(unsigned long kexec_flags, void *entry)
> {
> int result;
> @@ -970,6 +994,7 @@ void usage(void)
> " to original kernel.\n"
> " -s, --kexec-file-syscall Use file based syscall for kexec operation\n"
> " -d, --debug Enable debugging to help spot a failure.\n"
> + " -S, --status Return 0 if the type (by default crash) is loaded.\n"
> "\n"
> "Supported kernel file types and options: \n");
> for (i = 0; i < file_types; i++) {
> @@ -981,7 +1006,7 @@ void usage(void)
> printf("\n");
> }
>
> -static int kexec_loaded(void)
> +static int __kexec_loaded(const char *file)
> {
> long ret = -1;
> FILE *fp;
> @@ -992,7 +1017,7 @@ static int kexec_loaded(void)
> if (xen_present())
> return 1;
>
> - fp = fopen("/sys/kernel/kexec_loaded", "r");
> + fp = fopen(file, "r");
> if (fp == NULL)
> return -1;
>
> @@ -1015,6 +1040,12 @@ static int kexec_loaded(void)
> return (int)ret;
> }
>
> +static int kexec_loaded(void)
> +{
> + return __kexec_loaded("/sys/kernel/kexec_loaded");
> +}
Since kexec_loaded() has been called at only one place, better to remove
above function and use __kexec_loaded() directly. And then you might not
need to rename kexec_loaded() to __kexec_loaded() as well.
> +
> +
> /*
> * Remove parameter from a kernel command line. Helper function by get_command_line().
> */
> @@ -1204,6 +1235,7 @@ int main(int argc, char *argv[])
> int do_unload = 0;
> int do_reuse_initrd = 0;
> int do_kexec_file_syscall = 0;
> + int do_status = 0;
> void *entry = 0;
> char *type = 0;
> char *endptr;
> @@ -1345,6 +1377,9 @@ int main(int argc, char *argv[])
> case OPT_KEXEC_FILE_SYSCALL:
> /* We already parsed it. Nothing to do. */
> break;
> + case OPT_STATUS:
> + do_status = 1;
why not to call k_status() here and then return so that you get rid of all
other changes in this function?
> + break;
> default:
> break;
> }
> @@ -1355,6 +1390,20 @@ int main(int argc, char *argv[])
> if (skip_sync)
> do_sync = 0;
>
> + if (do_status) {
> + if (kexec_flags == 0)
> + kexec_flags = KEXEC_ON_CRASH;
> + do_load = 0;
> + do_reuse_initrd = 0;
> + do_unload = 0;
> + do_load = 0;
> + do_shutdown = 0;
> + do_sync = 0;
> + do_ifdown = 0;
> + do_exec = 0;
> + do_load_jump_back_helper = 0;
> + }
> +
> if (do_load && (kexec_flags & KEXEC_ON_CRASH) &&
> !is_crashkernel_mem_reserved()) {
> die("Memory for crashkernel is not reserved\n"
> @@ -1392,7 +1441,9 @@ int main(int argc, char *argv[])
> check_reuse_initrd();
> arch_reuse_initrd();
> }
> -
> + if (do_status) {
> + result = k_status(kexec_flags);
> + }
> if (do_unload) {
> if (do_kexec_file_syscall)
> result = kexec_file_unload(kexec_file_flags);
> diff --git a/kexec/kexec.h b/kexec/kexec.h
> index 9194f1c..2b06f59 100644
> --- a/kexec/kexec.h
> +++ b/kexec/kexec.h
> @@ -219,6 +219,7 @@ extern int file_types;
> #define OPT_TYPE 't'
> #define OPT_PANIC 'p'
> #define OPT_KEXEC_FILE_SYSCALL 's'
> +#define OPT_STATUS 'S'
> #define OPT_MEM_MIN 256
> #define OPT_MEM_MAX 257
> #define OPT_REUSE_INITRD 258
> @@ -245,8 +246,9 @@ extern int file_types;
> { "reuseinitrd", 0, 0, OPT_REUSE_INITRD }, \
> { "kexec-file-syscall", 0, 0, OPT_KEXEC_FILE_SYSCALL }, \
> { "debug", 0, 0, OPT_DEBUG }, \
> + { "status", 0, 0, OPT_STATUS }, \
>
> -#define KEXEC_OPT_STR "h?vdfxyluet:ps"
> +#define KEXEC_OPT_STR "h?vdfxyluet:psS"
>
> extern void dbgprint_mem_range(const char *prefix, struct memory_range *mr, int nr_mr);
> extern void die(const char *fmt, ...)
> @@ -311,5 +313,6 @@ int xen_present(void);
> int xen_kexec_load(struct kexec_info *info);
> int xen_kexec_unload(uint64_t kexec_flags);
> void xen_kexec_exec(void);
> +int xen_kexec_status(uint64_t kexec_flags);
>
> #endif /* KEXEC_H */
>
~Pratyush
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