userland dtrace from shared library

userland-dtrace-so.md

Userland arguments work for functions from the main object, but not those in shared libraries.

An example from the main smbd program is ok:

$ dtrace -lvn 'pid$target:smbd:samba_cmdline_init:entry' -p 76224 
   ID   PROVIDER            MODULE                          FUNCTION NAME
96158   pid76224              smbd                samba_cmdline_init entry

        Probe Description Attributes
                Identifier Names: Private
                Data Semantics:   Private
                Dependency Class: Unknown

        Argument Attributes
                Identifier Names: Private
                Data Semantics:   Private
                Dependency Class: Unknown

        Argument Types
                args[0]: userland TALLOC_CTX *
                args[1]: userland enum samba_cmdline_config_type
                args[2]: userland _Bool

But any from libsmbd-base-samba4.so (or indeed any of the Samba shared libraries) are all listed as "unknown":

$ dtrace -lvn 'pid$target::readlink_talloc:entry' -p 76224 
   ID   PROVIDER            MODULE                          FUNCTION NAME
97390   pid76224 libsmbd-base-samba4.so                   readlink_talloc entry

        Probe Description Attributes
                Identifier Names: Private
                Data Semantics:   Private
                Dependency Class: Unknown

        Argument Attributes
                Identifier Names: Private
                Data Semantics:   Private
                Dependency Class: Unknown

        Argument Types
                args[0]: (unknown)
                args[1]: (unknown)
                args[2]: (unknown)
                args[3]: (unknown)

As far as I can see they are built in the same way, and CTF is generated correctly for them. For example ctfdump -c:

$ ctfdump -c /opt/local/sbin/smbd | grep samba_cmdline_init
extern _Bool samba_cmdline_init(TALLOC_CTX *, enum samba_cmdline_config_type, _Bool);

$ ctfdump -c /opt/local/lib/samba/private/libsmbd-base-samba4.so | grep readlink_talloc
extern NTSTATUS readlink_talloc(TALLOC_CTX *, struct files_struct *, struct smb_filename *, char **);

libdtrace DEBUG: discovering probe pid76224:libsmbd-base-samba4.so:readlink_talloc:entry id=97390
libdtrace DEBUG: grabbed pid 76224 (cached)
libdtrace DEBUG: loaded 158 ctf modules for pid 76224
libdtrace DEBUG: grabbed pid 76224 (cached)
libdtrace DEBUG: Trying to find userland type: libsmbd
libdtrace DEBUG: failed to resolve input type userland pid76224`libsmbd-base-samba4.so`TALLOC_CTX * for pid76224:libsmbd-base-samba4.so:readlink_talloc:entry arg #1: syntax error near "pid76224`libsmbd"
libdtrace DEBUG: failed to resolve output type  for pid76224:libsmbd-base-samba4.so:readlink_talloc:entry arg #1: empty D program translation unit
libdtrace DEBUG: Trying to find userland type: libsmbd
libdtrace DEBUG: failed to resolve input type userland struct pid76224`libsmbd-base-samba4.so`files_struct * for pid76224:libsmbd-base-samba4.so:readlink_talloc:entry arg #2: syntax error near "-"
libdtrace DEBUG: failed to resolve output type  for pid76224:libsmbd-base-samba4.so:readlink_talloc:entry arg #2: empty D program translation unit
libdtrace DEBUG: Trying to find userland type: libsmbd
libdtrace DEBUG: failed to resolve input type userland struct pid76224`libsmbd-base-samba4.so`smb_filename * for pid76224:libsmbd-base-samba4.so:readlink_talloc:entry arg #3: syntax error near "-"
libdtrace DEBUG: failed to resolve output type  for pid76224:libsmbd-base-samba4.so:readlink_talloc:entry arg #3: empty D program translation unit
libdtrace DEBUG: Trying to find userland type: libsmbd
libdtrace DEBUG: failed to resolve input type userland pid76224`libsmbd-base-samba4.so`char ** for pid76224:libsmbd-base-samba4.so:readlink_talloc:entry arg #4: syntax error near "pid76224`libsmbd"
libdtrace DEBUG: failed to resolve output type  for pid76224:libsmbd-base-samba4.so:readlink_talloc:entry arg #4: empty D program translation unit
libdtrace DEBUG: set context to pid76224::readlink_talloc:entry [0] prp=16119d0 attr=[p/p/u] argc=4
libdtrace DEBUG: set label to <action list>
libdtrace DEBUG: set label to <NULL>
libdtrace DEBUG: releasing pid 76224