Author: markj
Date: Mon Aug  4 15:36:22 2014
New Revision: 269520
URL: http://svnweb.freebsd.org/changeset/base/269520

Log:
  MFC r256571:
  Add a function, memstr, which can be used to convert a buffer of
  null-separated strings to a single string. This can be used to print the
  full arguments of a process using execsnoop (from the DTrace toolkit) or
  with the following one-liner:
  
  dtrace -n 'syscall::execve:return {trace(curpsinfo->pr_psargs);}'
  
  Note that this relies on the process arguments being cached via the struct
  proc, which means that it will not work for argvs longer than
  kern.ps_arg_cache_limit. However, the following rather non-portable
  script can be used to extract any argv at exec time:
  
  fbt::kern_execve:entry
  {
      printf("%s", memstr(args[1]->begin_argv, ' ',
          args[1]->begin_envv - args[1]->begin_argv));
  }
  
  The debug.dtrace.memstr_max sysctl limits the maximum argument size to
  memstr().

Modified:
  stable/10/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c
  stable/10/cddl/lib/libdtrace/psinfo.d
  stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
  stable/10/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h
  stable/10/sys/cddl/dev/dtrace/dtrace_sysctl.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c
==============================================================================
--- stable/10/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c   Mon Aug 
 4 14:56:49 2014        (r269519)
+++ stable/10/cddl/contrib/opensolaris/lib/libdtrace/common/dt_open.c   Mon Aug 
 4 15:36:22 2014        (r269520)
@@ -323,6 +323,10 @@ static const dt_ident_t _dtrace_globals[
        &dt_idops_func, "void(@)" },
 { "memref", DT_IDENT_FUNC, 0, DIF_SUBR_MEMREF, DT_ATTR_STABCMN, DT_VERS_1_1,
        &dt_idops_func, "uintptr_t *(void *, size_t)" },
+#if !defined(sun)
+{ "memstr", DT_IDENT_FUNC, 0, DIF_SUBR_MEMSTR, DT_ATTR_STABCMN, DT_VERS_1_0,
+       &dt_idops_func, "string(void *, char, size_t)" },
+#endif
 { "min", DT_IDENT_AGGFUNC, 0, DTRACEAGG_MIN, DT_ATTR_STABCMN, DT_VERS_1_0,
        &dt_idops_func, "void(@)" },
 { "mod", DT_IDENT_ACTFUNC, 0, DT_ACT_MOD, DT_ATTR_STABCMN,

Modified: stable/10/cddl/lib/libdtrace/psinfo.d
==============================================================================
--- stable/10/cddl/lib/libdtrace/psinfo.d       Mon Aug  4 14:56:49 2014        
(r269519)
+++ stable/10/cddl/lib/libdtrace/psinfo.d       Mon Aug  4 15:36:22 2014        
(r269520)
@@ -57,7 +57,8 @@ translator psinfo_t < struct proc *T > {
        pr_gid = T->p_ucred->cr_rgid;
        pr_egid = T->p_ucred->cr_groups[0];
        pr_addr = 0;
-       pr_psargs = stringof(T->p_args->ar_args);
+       pr_psargs = (T->p_args->ar_args == 0) ? "" :
+           memstr(T->p_args->ar_args, ' ', T->p_args->ar_length);
        pr_arglen = T->p_args->ar_length;
        pr_jailid = T->p_ucred->cr_prison->pr_id;
 };

Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
==============================================================================
--- stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c   Mon Aug 
 4 14:56:49 2014        (r269519)
+++ stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c   Mon Aug 
 4 15:36:22 2014        (r269520)
@@ -184,6 +184,9 @@ hrtime_t    dtrace_deadman_interval = NANOS
 hrtime_t       dtrace_deadman_timeout = (hrtime_t)10 * NANOSEC;
 hrtime_t       dtrace_deadman_user = (hrtime_t)30 * NANOSEC;
 hrtime_t       dtrace_unregister_defunct_reap = (hrtime_t)60 * NANOSEC;
+#if !defined(sun)
+int            dtrace_memstr_max = 4096;
+#endif
 
 /*
  * DTrace External Variables
@@ -5807,6 +5810,45 @@ inetout: regs[rd] = (uintptr_t)end + 1;
                break;
        }
 
+#if !defined(sun)
+       case DIF_SUBR_MEMSTR: {
+               char *str = (char *)mstate->dtms_scratch_ptr;
+               uintptr_t mem = tupregs[0].dttk_value;
+               char c = tupregs[1].dttk_value;
+               size_t size = tupregs[2].dttk_value;
+               uint8_t n;
+               int i;
+
+               regs[rd] = 0;
+
+               if (size == 0)
+                       break;
+
+               if (!dtrace_canload(mem, size - 1, mstate, vstate))
+                       break;
+
+               if (!DTRACE_INSCRATCH(mstate, size)) {
+                       DTRACE_CPUFLAG_SET(CPU_DTRACE_NOSCRATCH);
+                       break;
+               }
+
+               if (dtrace_memstr_max != 0 && size > dtrace_memstr_max) {
+                       *flags |= CPU_DTRACE_ILLOP;
+                       break;
+               }
+
+               for (i = 0; i < size - 1; i++) {
+                       n = dtrace_load8(mem++);
+                       str[i] = (n == 0) ? c : n;
+               }
+               str[size - 1] = 0;
+
+               regs[rd] = (uintptr_t)str;
+               mstate->dtms_scratch_ptr += size;
+               break;
+       }
+#endif
+
        case DIF_SUBR_TYPEREF: {
                uintptr_t size = 4 * sizeof(uintptr_t);
                uintptr_t *typeref = (uintptr_t *) 
P2ROUNDUP(mstate->dtms_scratch_ptr, sizeof(uintptr_t));
@@ -10033,6 +10075,9 @@ dtrace_difo_validate_helper(dtrace_difo_
                            subr == DIF_SUBR_NTOHL ||
                            subr == DIF_SUBR_NTOHLL ||
                            subr == DIF_SUBR_MEMREF ||
+#if !defined(sun)
+                           subr == DIF_SUBR_MEMSTR ||
+#endif
                            subr == DIF_SUBR_TYPEREF)
                                break;
 

Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h
==============================================================================
--- stable/10/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h      Mon Aug 
 4 14:56:49 2014        (r269519)
+++ stable/10/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h      Mon Aug 
 4 15:36:22 2014        (r269520)
@@ -311,6 +311,7 @@ typedef enum dtrace_probespec {
 #define        DIF_SUBR_SX_SHARED_HELD         48
 #define        DIF_SUBR_SX_EXCLUSIVE_HELD      49
 #define        DIF_SUBR_SX_ISEXCLUSIVE         50
+#define        DIF_SUBR_MEMSTR                 51
 #define        DIF_SUBR_GETF                   52
 #define        DIF_SUBR_JSON                   53
 #define        DIF_SUBR_STRTOLL                54

Modified: stable/10/sys/cddl/dev/dtrace/dtrace_sysctl.c
==============================================================================
--- stable/10/sys/cddl/dev/dtrace/dtrace_sysctl.c       Mon Aug  4 14:56:49 
2014        (r269519)
+++ stable/10/sys/cddl/dev/dtrace/dtrace_sysctl.c       Mon Aug  4 15:36:22 
2014        (r269520)
@@ -89,3 +89,6 @@ SYSCTL_LONG(_kern_dtrace, OID_AUTO, dof_
 
 SYSCTL_LONG(_kern_dtrace, OID_AUTO, helper_actions_max, CTLFLAG_RW,
     &dtrace_helper_actions_max, 0, "maximum number of allowed helper actions");
+
+SYSCTL_INT(_kern_dtrace, OID_AUTO, memstr_max, CTLFLAG_RW, &dtrace_memstr_max,
+    0, "largest allowed argument to memstr(), 0 indicates no limit");
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