Use lttng-modules ABI version ioctl

Check compatibility between lttng-modules and tools using a version
numbering specifically for the ABI, rather than relying on the major
version of lttng-modules per se. This takes into account that we
sometimes depend on lock-step updates of the toolchain, including
tools and modules.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 2aeef263d6bd38c7238db96b0c99de4d230bdee2..00bfbbc2be5400d460e2c7dd7c273335f7d444b4 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -26,6 +26,7 @@
 
 #include <common/common.h>
 #include <common/kernel-ctl/kernel-ctl.h>
+#include <common/kernel-ctl/kernel-ioctl.h>
 #include <common/sessiond-comm/sessiond-comm.h>
 
 #include "consumer.h"
@@ -698,6 +699,7 @@ int kernel_validate_version(int tracer_fd)
 {
        int ret;
        struct lttng_kernel_tracer_version version;
+       struct lttng_kernel_tracer_abi_version abi_version;
 
        ret = kernctl_tracer_version(tracer_fd, &version);
        if (ret < 0) {
@@ -706,17 +708,28 @@ int kernel_validate_version(int tracer_fd)
        }
 
        /* Validate version */
-       if (version.major != KERN_MODULES_PRE_MAJOR
-               && version.major != KERN_MODULES_MAJOR) {
+       if (version.major != VERSION_MAJOR) {
+               ERR("Kernel tracer major version (%d) is not compatible with lttng-tools major version (%d)",
+                       version.major, VERSION_MAJOR);
                goto error_version;
        }
-
-       DBG2("Kernel tracer version validated (major version %d)", version.major);
+       ret = kernctl_tracer_abi_version(tracer_fd, &abi_version);
+       if (ret < 0) {
+               ERR("Failed at getting lttng-modules ABI version");
+               goto error;
+       }
+       if (abi_version.major != LTTNG_MODULES_ABI_MAJOR_VERSION) {
+               ERR("Kernel tracer ABI version (%d.%d) is not compatible with expected ABI major version (%d.*)",
+                       abi_version.major, abi_version.minor,
+                       LTTNG_MODULES_ABI_MAJOR_VERSION);
+               goto error;
+       }
+       DBG2("Kernel tracer version validated (%d.%d, ABI %d.%d)",
+                       version.major, version.minor,
+                       abi_version.major, abi_version.minor);
        return 0;
 
 error_version:
-       ERR("Kernel major version %d is not compatible (supporting <= %d)",
-                       version.major, KERN_MODULES_MAJOR)
        ret = -1;
 
 error:

diff --git a/src/common/kernel-ctl/kernel-ctl.c b/src/common/kernel-ctl/kernel-ctl.c
index a387b93bf87f0334365c3217c95537cf1487e29b..f3ef93d3fd5a52bf1d8970d5d068a44cb8120541 100644 (file)
--- a/src/common/kernel-ctl/kernel-ctl.c
+++ b/src/common/kernel-ctl/kernel-ctl.c
@@ -346,6 +346,12 @@ end:
        return ret;
 }
 
+int kernctl_tracer_abi_version(int fd,
+               struct lttng_kernel_tracer_abi_version *v)
+{
+       return ioctl(fd, LTTNG_KERNEL_TRACER_ABI_VERSION, v);
+}
+
 int kernctl_wait_quiescent(int fd)
 {
        return compat_ioctl_no_arg(fd, LTTNG_KERNEL_OLD_WAIT_QUIESCENT,

diff --git a/src/common/kernel-ctl/kernel-ctl.h b/src/common/kernel-ctl/kernel-ctl.h
index 4ef1b879562774a87a57bd3bdab41a300203912a..d9e6c54a4a408313e35c660fccc62476987d87b2 100644 (file)
--- a/src/common/kernel-ctl/kernel-ctl.h
+++ b/src/common/kernel-ctl/kernel-ctl.h
@@ -38,6 +38,7 @@ int kernctl_stop_session(int fd);
 int kernctl_tracepoint_list(int fd);
 int kernctl_syscall_list(int fd);
 int kernctl_tracer_version(int fd, struct lttng_kernel_tracer_version *v);
+int kernctl_tracer_abi_version(int fd, struct lttng_kernel_tracer_abi_version *v);
 int kernctl_wait_quiescent(int fd);
 int kernctl_calibrate(int fd, struct lttng_kernel_calibrate *calibrate);
 

diff --git a/src/common/kernel-ctl/kernel-ioctl.h b/src/common/kernel-ctl/kernel-ioctl.h
index 475a066c31ca8f89f0d2b181e9bd826419172360..927de6fd69409f3e8e25119b36715b1ec753547f 100644 (file)
--- a/src/common/kernel-ctl/kernel-ioctl.h
+++ b/src/common/kernel-ctl/kernel-ioctl.h
@@ -19,6 +19,9 @@
 #ifndef _LTT_KERNEL_IOCTL_H
 #define _LTT_KERNEL_IOCTL_H
 
+#define LTTNG_MODULES_ABI_MAJOR_VERSION                1
+#define LTTNG_MODULES_ABI_MINOR_VERSION                0
+
 /* Get a snapshot of the current ring buffer producer and consumer positions */
 #define RING_BUFFER_SNAPSHOT                _IO(0xF6, 0x00)
 /* Get the consumer position (iteration start) */
@@ -104,6 +107,8 @@
 #define LTTNG_KERNEL_CALIBRATE                 \
        _IOWR(0xF6, 0x49, struct lttng_kernel_calibrate)
 #define LTTNG_KERNEL_SYSCALL_LIST              _IO(0xF6, 0x4A)
+#define LTTNG_KERNEL_TRACER_ABI_VERSION                \
+       _IOR(0xF6, 0x4B, struct lttng_kernel_tracer_abi_version)
 
 /* Session FD ioctl */
 #define LTTNG_KERNEL_METADATA                  \

diff --git a/src/common/lttng-kernel.h b/src/common/lttng-kernel.h
index 4df3240055092df4e0d945c89165f4c21cc118e4..abd22c99b5a42c011f5d9915ed73340bbe41bac6 100644 (file)
--- a/src/common/lttng-kernel.h
+++ b/src/common/lttng-kernel.h
@@ -124,6 +124,11 @@ struct lttng_kernel_tracer_version {
        uint32_t patchlevel;
 } LTTNG_PACKED;
 
+struct lttng_kernel_tracer_abi_version {
+       uint32_t major;
+       uint32_t minor;
+} LTTNG_PACKED;
+
 enum lttng_kernel_calibrate_type {
        LTTNG_KERNEL_CALIBRATE_KRETPROBE,
 };