01/01: gnu: strace: Fix build failure on Linux-Libre 4.16.

[Marius Bakke]

mbakke pushed a commit to branch master
in repository guix.

commit 6e7be7d37abfb70098e4ce64c3508d992145d9c8
Author: Marius Bakke <address@hidden>
Date:   Sun May 6 20:11:40 2018 +0200

    gnu: strace: Fix build failure on Linux-Libre 4.16.
    
    * gnu/packages/patches/strace-kernel-4.16.patch: New file.
    * gnu/local.mk (dist_patch_DATA): Register it.
    * gnu/packages/linux.scm (strace)][source](patches): New field.
---
 gnu/local.mk                                  |  1 +
 gnu/packages/linux.scm                        |  1 +
 gnu/packages/patches/strace-kernel-4.16.patch | 92 +++++++++++++++++++++++++++
 3 files changed, 94 insertions(+)

diff --git a/gnu/local.mk b/gnu/local.mk
index cfe698d..bd99883 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1096,6 +1096,7 @@ dist_patch_DATA =                                         
\
   %D%/packages/patches/slim-login.patch                                \
   %D%/packages/patches/sooperlooper-build-with-wx-30.patch     \
   %D%/packages/patches/steghide-fixes.patch                    \
+  %D%/packages/patches/strace-kernel-4.16.patch                        \
   %D%/packages/patches/superlu-dist-scotchmetis.patch          \
   %D%/packages/patches/swish-e-search.patch                    \
   %D%/packages/patches/swish-e-format-security.patch           \
diff --git a/gnu/packages/linux.scm b/gnu/packages/linux.scm
index fe1090e..ac28b2b 100644
--- a/gnu/packages/linux.scm
+++ b/gnu/packages/linux.scm
@@ -949,6 +949,7 @@ Zerofree requires the file system to be unmounted or 
mounted read-only.")
              (method url-fetch)
              (uri (string-append home-page "/files/" version
                                  "/strace-" version ".tar.xz"))
+             (patches (search-patches "strace-kernel-4.16.patch"))
              (sha256
               (base32
                "17dkpnsjxmys1ydidm9wcvc3wscsz44fmlxw3dclspn9cj9d1306"))))
diff --git a/gnu/packages/patches/strace-kernel-4.16.patch 
b/gnu/packages/patches/strace-kernel-4.16.patch
new file mode 100644
index 0000000..e86d3be
--- /dev/null
+++ b/gnu/packages/patches/strace-kernel-4.16.patch
@@ -0,0 +1,92 @@
+Fix test failure when using Linux-Libre >= 4.16.
+
+Taken from upstream:
+https://github.com/strace/strace/commit/bcff87c31c0f27c678a43d6b7f67dab363a974fa
+
+From bcff87c31c0f27c678a43d6b7f67dab363a974fa Mon Sep 17 00:00:00 2001
+From: Masatake YAMATO <address@hidden>
+Date: Wed, 2 May 2018 17:11:07 +0900
+Subject: [PATCH] tests/ioctl_kvm_run.c: handle cpuid at the end of vcpu dentry
+
+Since Linux 4.16, kernel appends the cpuid as suffix to the entry
+for a kvm vcpu in /proc/$pid/fd like:
+
+    anon_inode:kvm-vcpu:0
+
+That was
+
+    anon_inode:kvm-vcpu
+
+This kernel change causes the test case failure on newer kernels.
+Update the test to deal with the new name as well as the old one.
+
+* tests/ioctl_kvm_run.c: Include unistd.h for using readlink(2).
+(vcpu_dev_should_have_cpuid): New function for detecting whether
+a proc entry for given fd has the cpuid suffix or not.
+(main): Trim vcpu_dev to remove the cpuid suffix if needed.
+(vcpu_dev): Remove const modifier.
+---
+ tests/ioctl_kvm_run.c | 29 ++++++++++++++++++++++++++++-
+ 1 file changed, 28 insertions(+), 1 deletion(-)
+
+diff --git a/tests/ioctl_kvm_run.c b/tests/ioctl_kvm_run.c
+index 179461430..e1bef5796 100644
+--- a/tests/ioctl_kvm_run.c
++++ b/tests/ioctl_kvm_run.c
+@@ -40,6 +40,7 @@
+ # include <string.h>
+ # include <sys/ioctl.h>
+ # include <sys/mman.h>
++# include <unistd.h>
+ # include <linux/kvm.h>
+ 
+ static int
+@@ -56,7 +57,7 @@ kvm_ioctl(int fd, unsigned long cmd, const char *cmd_str, 
void *arg)
+ 
+ static const char dev[] = "/dev/kvm";
+ static const char vm_dev[] = "anon_inode:kvm-vm";
+-static const char vcpu_dev[] = "anon_inode:kvm-vcpu";
++static char vcpu_dev[] = "anon_inode:kvm-vcpu:0";
+ static size_t page_size;
+ 
+ extern const char code[];
+@@ -165,6 +166,23 @@ run_kvm(const int vcpu_fd, struct kvm_run *const run, 
const size_t mmap_size,
+       }
+ }
+ 
++static int
++vcpu_dev_should_have_cpuid(int fd)
++{
++      int r = 0;
++      char *filename = NULL;
++      char buf[sizeof(vcpu_dev)];
++
++      if (asprintf(&filename, "/proc/%d/fd/%d", getpid(), fd) < 0)
++              error_msg_and_fail("asprintf");
++
++      if (readlink(filename, buf, sizeof(buf)) == sizeof(buf) - 1
++          && (memcmp(buf, vcpu_dev, sizeof(buf) - 1) == 0))
++              r = 1;
++      free(filename);
++      return r;
++}
++
+ int
+ main(void)
+ {
+@@ -208,6 +226,15 @@ main(void)
+              (unsigned long) page_size, (unsigned long) page_size, mem);
+ 
+       int vcpu_fd = KVM_IOCTL(vm_fd, KVM_CREATE_VCPU, NULL);
++      if (!vcpu_dev_should_have_cpuid(vcpu_fd))
++              /*
++               * This is an older kernel that doesn't place a cpuid
++               * at the end of the dentry associated with vcpu_fd.
++               * Trim the cpuid part of vcpu_dev like:
++               * "anon_inode:kvm-vcpu:0" -> "anon_inode:kvm-vcpu"
++               */
++              vcpu_dev[strlen (vcpu_dev) - 2] = '\0';
++
+       printf("ioctl(%d<%s>, KVM_CREATE_VCPU, 0) = %d<%s>\n",
+              vm_fd, vm_dev, vcpu_fd, vcpu_dev);
+