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Tag: ktap

elfutils-libelf isn’t libelf!

These days, I am suffering with building ktap on Suse. Since Suse doesn’t provide elfutils-libelf-devel nor libelf-devel, so I decide to build libelf from source code.

First, I install the newest version (0.8.13) from libelf site. Building ktap generate the following errors:

cc  -Wall -O2  -o userspace/kp_main.o -c userspace/kp_main.c
In file included from /usr/local/include/libelf/libelf.h:25:0,
                 from /usr/local/include/libelf/gelf.h:28,
                 from /usr/local/include/gelf.h:1,
                 from userspace/kp_symbol.h:28,
                 from userspace/kp_main.c:40:
/usr/lib64/gcc/x86_64-suse-linux/4.8/include/stddef.h:147:26: error: conflicting types for ‘ptrdiff_t’
 typedef __PTRDIFF_TYPE__ ptrdiff_t;
                          ^
In file included from userspace/kp_main.c:37:0:
userspace/../include/ktap_types.h:20:13: note: previous declaration of ‘ptrdiff_t’ was here
 typedef int ptrdiff_t;
             ^
Makefile:119: recipe for target 'userspace/kp_main.o' failed
make: *** [userspace/kp_main.o] Error 1

The root cause is in this version, libelf.h contains stddef.h which defines ptrdiff_t, while ktap_types.h also defines it. So I decide to use an older version of libelf.

Second, I install the 0.8.5 version of libelf. This time, the compilation generates the following errors:

userspace/kp_symbol.c: In function ‘find_load_address’:
userspace/kp_symbol.c:69:2: warning: implicit declaration of function ‘elf_getphdrnum’ [-Wimplicit-function-declaration]
  if (elf_getphdrnum(elf, &phdrnum))
  ^
userspace/kp_symbol.c: At top level:
userspace/kp_symbol.c:189:44: error: unknown type name ‘GElf_Nhdr’
 static const char *sdt_note_name(Elf *elf, GElf_Nhdr *nhdr, const char *data)
                                            ^
userspace/kp_symbol.c: In function ‘dso_sdt_notes’:
userspace/kp_symbol.c:215:2: error: unknown type name ‘GElf_Nhdr’
  GElf_Nhdr nhdr;
  ^
userspace/kp_symbol.c:222:2: warning: implicit declaration of function ‘elf_getshdrstrndx’ [-Wimplicit-function-declaration]
  if (elf_getshdrstrndx(elf, &shstrndx) != 0)
  ^
userspace/kp_symbol.c:238:3: warning: implicit declaration of function ‘gelf_getnote’ [-Wimplicit-function-declaration]
   (next = gelf_getnote(data, offset, &nhdr, &name_off, &desc_off)) > 0;
   ^
userspace/kp_symbol.c:243:11: error: request for member ‘n_namesz’ in something not a structure or union
   if (nhdr.n_namesz != sizeof(SDT_NOTE_NAME) ||
           ^
userspace/kp_symbol.c:248:3: warning: implicit declaration of function ‘sdt_note_name’ [-Wimplicit-function-declaration]
   name = sdt_note_name(elf, &nhdr, sdt_note_data(data, desc_off));
   ^
userspace/kp_symbol.c:248:8: warning: assignment makes pointer from integer without a cast [enabled by default]
   name = sdt_note_name(elf, &nhdr, sdt_note_data(data, desc_off));
        ^
userspace/kp_symbol.c:253:10: error: request for member ‘n_descsz’ in something not a structure or union
      nhdr.n_descsz, nhdr.n_type);
          ^
userspace/kp_symbol.c:253:25: error: request for member ‘n_type’ in something not a structure or union
      nhdr.n_descsz, nhdr.n_type);
                         ^
Makefile:134: recipe for target 'userspace/kp_symbol.o' failed
make: *** [userspace/kp_symbol.o] Error 1

After googling, I find this issue: elfutils-libelf isn’t libelf! So I install elfutils-libelf from source code (please refer this post), then the build of ktap is OK!

 

Install ktap on RHEL

My RHEL is 7.0, the minimal installation. Build ktap, it outputs the following error:

[root@redhat ktap-master]# make
    CHK libelf
Makefile:108: No libelf found, disables symbol resolving, please install elfutils-libelf-devel/libelf-dev
make -C /lib/modules/3.10.0-123.el7.x86_64/build M=/root/ktap-master modules
make: *** /lib/modules/3.10.0-123.el7.x86_64/build: No such file or directory.  Stop.
make: *** [mod] Error 2

(1)

To fix “No libelf found, disables ...” error, you need to install elfutils-libelf-devel package:

[root@redhat ktap-master]# yum install elfutils-libelf-devel
Loaded plugins: product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Resolving Dependencies
--> Running transaction check
---> Package elfutils-libelf-devel.x86_64 0:0.158-3.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved
......

(2)

To fix “*** /lib/modules/3.10.0-123.el7.x86_64/build: No such file or directory.” error, you need to install kernel-devel package:

[root@redhat ktap-master]# yum install kernel-devel
Loaded plugins: product-id, subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Resolving Dependencies
--> Running transaction check
---> Package kernel-devel.x86_64 0:3.10.0-123.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

Then make is OK!

 

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