[PATCH v2] kexec: implemented XEN KEXEC STATUS to determine if an image is loaded
Eric DeVolder
eric.devolder at oracle.com
Fri Jan 20 09:03:54 PST 2017
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>
Signed-off-by: Eric DeVolder <eric.devolder at oracle.com>
---
Note: The corresponding Xen changes have been committed
to the Xen staging branch. Follow this thread:
https://lists.xenproject.org/archives/html/xen-devel/2017-01/msg01570.html
CC: Andrew Cooper <andrew.cooper3 at citrix.com>
CC: kexec at lists.infradead.org
CC: xen-devel at lists.xenproject.org
CC: Daniel Kiper <daniel.kiper at oracle.com>
v0: First version (internal product).
v1: Posted on kexec mailing list. Changed -s to -S
v2: Incorporated feedback from kexec mailing list
---
configure.ac | 8 ++++++-
kexec/kexec-xen.c | 26 +++++++++++++++++++++++
kexec/kexec.8 | 6 ++++++
kexec/kexec.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++-------
kexec/kexec.h | 5 ++++-
5 files changed, 98 insertions(+), 9 deletions(-)
diff --git a/configure.ac b/configure.ac
index 3044185..c6e864b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -165,8 +165,14 @@ fi
dnl find Xen control stack libraries
if test "$with_xen" = yes ; then
AC_CHECK_HEADER(xenctrl.h,
- [AC_CHECK_LIB(xenctrl, xc_kexec_load, ,
+ [AC_CHECK_LIB(xenctrl, xc_kexec_load, [ have_xenctrl_h=yes ],
AC_MSG_NOTICE([Xen support disabled]))])
+if test "$have_xenctrl_h" = yes ; then
+ AC_CHECK_LIB(xenctrl, xc_kexec_status,
+ AC_DEFINE(HAVE_KEXEC_CMD_STATUS, 1,
+ [The kexec_status call is available]),
+ AC_MSG_NOTICE([The kexec_status call is not available]))
+fi
fi
dnl ---Sanity checks
diff --git a/kexec/kexec-xen.c b/kexec/kexec-xen.c
index 24a4191..2b448d3 100644
--- a/kexec/kexec-xen.c
+++ b/kexec/kexec-xen.c
@@ -105,6 +105,27 @@ 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 = -1;
+
+#ifdef HAVE_KEXEC_CMD_STATUS
+ 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);
+#endif
+
+ return ret;
+}
+
void xen_kexec_exec(void)
{
xc_interface *xch;
@@ -130,6 +151,11 @@ int xen_kexec_unload(uint64_t kexec_flags)
return -1;
}
+int xen_kexec_status(uint64_t kexec_flags)
+{
+ return -1;
+}
+
void xen_kexec_exec(void)
{
}
diff --git a/kexec/kexec.8 b/kexec/kexec.8
index 4d0c1d1..f4b39a6 100644
--- a/kexec/kexec.8
+++ b/kexec/kexec.8
@@ -107,6 +107,12 @@ command:
.B \-d\ (\-\-debug)
Enable debugging messages.
.TP
+.B \-S\ (\-\-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 this option supersedes other options
+and it will
+.BR not\ load\ or\ 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..defbbe3 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -51,6 +51,9 @@
#include "kexec-lzma.h"
#include <arch/options.h>
+#define KEXEC_LOADED_PATH "/sys/kernel/kexec_loaded"
+#define KEXEC_CRASH_LOADED_PATH "/sys/kernel/kexec_crash_loaded"
+
unsigned long long mem_min = 0;
unsigned long long mem_max = ULONG_MAX;
static unsigned long kexec_flags = 0;
@@ -58,6 +61,8 @@ static unsigned long kexec_flags = 0;
static unsigned long kexec_file_flags = 0;
int kexec_debug = 0;
+static int kexec_loaded(const char *file);
+
void dbgprint_mem_range(const char *prefix, struct memory_range *mr, int nr_mr)
{
int i;
@@ -890,8 +895,6 @@ 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;
@@ -909,7 +912,7 @@ static int my_load_jump_back_helper(unsigned long kexec_flags, void *entry)
{
int result;
- if (kexec_loaded()) {
+ if (kexec_loaded(KEXEC_LOADED_PATH)) {
fprintf(stderr, "There is kexec kernel loaded, make sure "
"you are in kexeced kernel.\n");
return -1;
@@ -970,6 +973,7 @@ 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 +985,7 @@ void usage(void)
printf("\n");
}
-static int kexec_loaded(void)
+static int kexec_loaded(const char *file)
{
long ret = -1;
FILE *fp;
@@ -992,7 +996,7 @@ 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 +1019,30 @@ static int kexec_loaded(void)
return (int)ret;
}
+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(KEXEC_CRASH_LOADED_PATH);
+ else
+ result = kexec_loaded(KEXEC_LOADED_PATH);
+ }
+ return result;
+}
+
+
/*
* Remove parameter from a kernel command line. Helper function by get_command_line().
*/
@@ -1204,6 +1232,7 @@ 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 +1374,9 @@ 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;
+ break;
default:
break;
}
@@ -1355,6 +1387,20 @@ 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 +1438,9 @@ 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);
@@ -1408,7 +1456,7 @@ int main(int argc, char *argv[])
kexec_flags, entry);
}
/* Don't shutdown unless there is something to reboot to! */
- if ((result == 0) && (do_shutdown || do_exec) && !kexec_loaded()) {
+ if ((result == 0) && (do_shutdown || do_exec) && !kexec_loaded(KEXEC_LOADED_PATH)) {
die("Nothing has been loaded!\n");
}
if ((result == 0) && do_shutdown) {
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 */
--
2.7.4
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