btrfs-progs: mkfs: detect version of running kernel

Use the uname syscall and parse the string.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/utils.c b/utils.c
index 72e6ae9..011e163 100644 (file)
--- a/utils.c
+++ b/utils.c
@@ -38,6 +38,7 @@
 #include <sys/statfs.h>
 #include <linux/magic.h>
 #include <getopt.h>
+#include <sys/utsname.h>
 
 #include "kerncompat.h"
 #include "radix-tree.h"
@@ -1555,6 +1556,53 @@ char* btrfs_parse_fs_features(char *namelist, u64 *flags)
        return NULL;
 }
 
+void print_kernel_version(FILE *stream, u32 version)
+{
+       u32 v[3];
+
+       v[0] = version & 0xFF;
+       v[1] = (version >> 8) & 0xFF;
+       v[2] = version >> 16;
+       fprintf(stream, "%u.%u", v[2], v[1]);
+       if (v[0])
+               fprintf(stream, ".%u", v[0]);
+}
+
+u32 get_running_kernel_version(void)
+{
+       struct utsname utsbuf;
+       char *tmp;
+       char *saveptr = NULL;
+       u32 version;
+
+       uname(&utsbuf);
+       if (strcmp(utsbuf.sysname, "Linux") != 0) {
+               error("unsupported system: %s", utsbuf.sysname);
+               exit(1);
+       }
+       /* 1.2.3-4-name */
+       tmp = strchr(utsbuf.release, '-');
+       if (tmp)
+               *tmp = 0;
+
+       tmp = strtok_r(utsbuf.release, ".", &saveptr);
+       if (!string_is_numerical(tmp))
+               return (u32)-1;
+       version = atoi(tmp) << 16;
+       tmp = strtok_r(NULL, ".", &saveptr);
+       if (!string_is_numerical(tmp))
+               return (u32)-1;
+       version |= atoi(tmp) << 8;
+       tmp = strtok_r(NULL, ".", &saveptr);
+       if (tmp) {
+               if (!string_is_numerical(tmp))
+                       return (u32)-1;
+               version |= atoi(tmp);
+       }
+
+       return version;
+}
+
 u64 btrfs_device_size(int fd, struct stat *st)
 {
        u64 size;

diff --git a/utils.h b/utils.h
index 117fed8..d382534 100644 (file)
--- a/utils.h
+++ b/utils.h
@@ -109,6 +109,8 @@ void btrfs_list_all_fs_features(u64 mask_disallowed);
 char* btrfs_parse_fs_features(char *namelist, u64 *flags);
 void btrfs_process_fs_features(u64 flags);
 void btrfs_parse_features_to_string(char *buf, u64 flags);
+void print_kernel_version(FILE *stream, u32 version);
+u32 get_running_kernel_version(void);
 
 struct btrfs_mkfs_config {
        char *label;