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authorAndi Kleen <ak@linux.intel.com>2011-08-19 16:15:10 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-29 13:29:16 -0700
commit512228f0be3af44bf5cf6cc5750ddd279bbedaf3 (patch)
tree4efaddfd0a353537b70c2a1059ebf49a1b624286
parent80b5405f36fba0caa9a142f978c00afa6aa7714c (diff)
Add a personality to report 2.6.x version numbers
commit be27425dcc516fd08245b047ea57f83b8f6f0903 upstream. I ran into a couple of programs which broke with the new Linux 3.0 version. Some of those were binary only. I tried to use LD_PRELOAD to work around it, but it was quite difficult and in one case impossible because of a mix of 32bit and 64bit executables. For example, all kind of management software from HP doesnt work, unless we pretend to run a 2.6 kernel. $ uname -a Linux svivoipvnx001 3.0.0-08107-g97cd98f #1062 SMP Fri Aug 12 18:11:45 CEST 2011 i686 i686 i386 GNU/Linux $ hpacucli ctrl all show Error: No controllers detected. $ rpm -qf /usr/sbin/hpacucli hpacucli-8.75-12.0 Another notable case is that Python now reports "linux3" from sys.platform(); which in turn can break things that were checking sys.platform() == "linux2": https://bugzilla.mozilla.org/show_bug.cgi?id=664564 It seems pretty clear to me though it's a bug in the apps that are using '==' instead of .startswith(), but this allows us to unbreak broken programs. This patch adds a UNAME26 personality that makes the kernel report a 2.6.40+x version number instead. The x is the x in 3.x. I know this is somewhat ugly, but I didn't find a better workaround, and compatibility to existing programs is important. Some programs also read /proc/sys/kernel/osrelease. This can be worked around in user space with mount --bind (and a mount namespace) To use: wget ftp://ftp.kernel.org/pub/linux/kernel/people/ak/uname26/uname26.c gcc -o uname26 uname26.c ./uname26 program Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--include/linux/personality.h1
-rw-r--r--kernel/sys.c38
2 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/personality.h b/include/linux/personality.h
index eec3bae164d4..8fc7dd1a57ff 100644
--- a/include/linux/personality.h
+++ b/include/linux/personality.h
@@ -22,6 +22,7 @@ extern int __set_personality(unsigned int);
* These occupy the top three bytes.
*/
enum {
+ UNAME26 = 0x0020000,
ADDR_NO_RANDOMIZE = 0x0040000, /* disable randomization of VA space */
FDPIC_FUNCPTRS = 0x0080000, /* userspace function ptrs point to descriptors
* (signal handling)
diff --git a/kernel/sys.c b/kernel/sys.c
index e4128b278f23..5c942cfc0e9f 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -38,6 +38,8 @@
#include <linux/fs_struct.h>
#include <linux/gfp.h>
#include <linux/syscore_ops.h>
+#include <linux/version.h>
+#include <linux/ctype.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
@@ -45,6 +47,8 @@
#include <linux/user_namespace.h>
#include <linux/kmsg_dump.h>
+/* Move somewhere else to avoid recompiling? */
+#include <generated/utsrelease.h>
#include <asm/uaccess.h>
#include <asm/io.h>
@@ -1124,6 +1128,34 @@ DECLARE_RWSEM(uts_sem);
#define override_architecture(name) 0
#endif
+/*
+ * Work around broken programs that cannot handle "Linux 3.0".
+ * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
+ */
+static int override_release(char __user *release, int len)
+{
+ int ret = 0;
+ char buf[len];
+
+ if (current->personality & UNAME26) {
+ char *rest = UTS_RELEASE;
+ int ndots = 0;
+ unsigned v;
+
+ while (*rest) {
+ if (*rest == '.' && ++ndots >= 3)
+ break;
+ if (!isdigit(*rest) && *rest != '.')
+ break;
+ rest++;
+ }
+ v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
+ snprintf(buf, len, "2.6.%u%s", v, rest);
+ ret = copy_to_user(release, buf, len);
+ }
+ return ret;
+}
+
SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
{
int errno = 0;
@@ -1133,6 +1165,8 @@ SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name)
errno = -EFAULT;
up_read(&uts_sem);
+ if (!errno && override_release(name->release, sizeof(name->release)))
+ errno = -EFAULT;
if (!errno && override_architecture(name))
errno = -EFAULT;
return errno;
@@ -1154,6 +1188,8 @@ SYSCALL_DEFINE1(uname, struct old_utsname __user *, name)
error = -EFAULT;
up_read(&uts_sem);
+ if (!error && override_release(name->release, sizeof(name->release)))
+ error = -EFAULT;
if (!error && override_architecture(name))
error = -EFAULT;
return error;
@@ -1188,6 +1224,8 @@ SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name)
if (!error && override_architecture(name))
error = -EFAULT;
+ if (!error && override_release(name->release, sizeof(name->release)))
+ error = -EFAULT;
return error ? -EFAULT : 0;
}
#endif