diff options
| -rw-r--r-- | tapsets.cxx | 74 | ||||
| -rw-r--r-- | translate.cxx | 8 |
2 files changed, 57 insertions, 25 deletions
diff --git a/tapsets.cxx b/tapsets.cxx index 3d4d0dc9..1003e25d 100644 --- a/tapsets.cxx +++ b/tapsets.cxx @@ -3253,7 +3253,7 @@ dwarf_query::add_probe_point(const string& funcname, } else if (dwfl_module_relocations (dw.module) > 0) { - // This is arelocatable module; libdwfl already knows its + // This is a relocatable module; libdwfl already knows its // sections, so we can relativize addr. int idx = dwfl_module_relocate_address (dw.module, &reloc_addr); const char* r_s = dwfl_module_relocation_info (dw.module, idx, NULL); @@ -3262,12 +3262,15 @@ dwarf_query::add_probe_point(const string& funcname, blacklist_section = reloc_section; if(reloc_section == "" && dwfl_module_relocations (dw.module) == 1) - blacklist_section = this->get_blacklist_section(addr); + { + blacklist_section = this->get_blacklist_section(addr); + reloc_section = ".dynamic"; + } } else { blacklist_section = this->get_blacklist_section(addr); - reloc_section = ""; + reloc_section = ".absolute"; } if (sess.verbose > 1) @@ -6558,14 +6561,10 @@ uprobe_derived_probe::uprobe_derived_probe (const string& function, derived_probe (q.base_probe, new probe_point (*q.base_loc) /* .components soon rewritten */ ), return_p (q.has_return), module (module), pid (pid), section (section), address (addr) { - // Assert relocation invariants - if (section == "" && dwfl_addr != addr) // addr should be absolute - throw semantic_error ("missing relocation base against", q.base_loc->tok); - if (section != "" && dwfl_addr == addr) // addr should be an offset - throw semantic_error ("inconsistent relocation address", q.base_loc->tok); - - // For now, we don't try to handle relocatable addresses - if (section != "") throw semantic_error ("cannot relocate user-space probes yet", q.base_loc->tok); + // We may receive probes on two types of ELF objects: ET_EXEC or ET_DYN. + // ET_EXEC ones need no further relocation on the addr(==dwfl_addr), whereas + // ET_DYN ones do (addr += run-time mmap base address). We tell these apart + // by the incoming section value (".absolute" vs. ".dynamic"). this->tok = q.base_probe->tok; @@ -6737,6 +6736,7 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s) s.op->newline() << "struct stap_uprobe_spec {"; s.op->newline(1) << "struct stap_task_finder_target finder;"; s.op->newline() << "unsigned long address;"; + s.op->newline() << "const char *pathname;"; s.op->newline() << "const char *pp;"; s.op->newline() << "void (*ph) (struct context*);"; s.op->newline() << "unsigned return_p:1;"; @@ -6748,10 +6748,13 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s) s.op->newline() << "{"; s.op->line() << " .finder = {"; if (p->pid != 0) - s.op->line() << " .pid=" << p->pid << ", "; - else + s.op->line() << " .pid=" << p->pid; + else if (p->section == ".absolute") s.op->line() << " .pathname=" << lex_cast_qstring(p->module) << ", "; + // else ".dynamic" gets pathname=0, pid=0, activating task_finder "global tracing" s.op->line() << "},"; + if (p->section != ".absolute") + s.op->line() << " .pathname=" << lex_cast_qstring(p->module) << ", "; s.op->line() << " .address=0x" << hex << p->address << dec << "UL,"; s.op->line() << " .pp=" << lex_cast_qstring (*p->sole_location()) << ","; s.op->line() << " .ph=&" << p->name << ","; @@ -6785,9 +6788,8 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s) common_probe_entryfn_epilogue (s.op); s.op->newline(-1) << "}"; - // XXX: This sort of plain process.begin/end callback will only work - // for uprobes on unrelocatable executables. - // + + // NB: Because these utrace callbacks only occur before / after // userspace instructions run, there is no concurrency control issue // between active uprobe callbacks and these registration / @@ -6801,14 +6803,11 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s) // calls occur outside the critical section. s.op->newline(); - s.op->newline() << "static int stap_uprobe_process_found (struct task_struct *tsk, int register_p, int process_p, struct stap_task_finder_target *tgt) {"; - s.op->newline(1) << "struct stap_uprobe_spec *sups = container_of(tgt, struct stap_uprobe_spec, finder);"; - s.op->newline() << "int spec_index = (sups - stap_uprobe_specs);"; + s.op->newline() << "static int stap_uprobe_change (struct task_struct *tsk, int register_p, unsigned long relocation, struct stap_uprobe_spec *sups) {"; + s.op->newline(1) << "int spec_index = (sups - stap_uprobe_specs);"; s.op->newline() << "int handled_p = 0;"; s.op->newline() << "int rc = 0;"; s.op->newline() << "int i;"; - // s.op->newline() << "printk (KERN_EMERG \"probe %d %d %d %p\\n\", tsk->tgid, register_p, process_p, tgt);"; - s.op->newline() << "if (! process_p) return 0;"; // we don't care about threads s.op->newline() << "mutex_lock (& stap_uprobes_lock);"; s.op->newline() << "for (i=0; i<NUMUPROBES; i++) {"; // XXX: slow linear search @@ -6819,17 +6818,18 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s) s.op->newline(1) << "sup->spec_index = spec_index;"; s.op->newline() << "if (sups->return_p) {"; s.op->newline(1) << "sup->urp.u.pid = tsk->tgid;"; - s.op->newline() << "sup->urp.u.vaddr = sups->address;"; + s.op->newline() << "sup->urp.u.vaddr = relocation + sups->address;"; s.op->newline() << "sup->urp.handler = &enter_uretprobe_probe;"; s.op->newline() << "rc = register_uretprobe (& sup->urp);"; s.op->newline(-1) << "} else {"; s.op->newline(1) << "sup->up.pid = tsk->tgid;"; - s.op->newline() << "sup->up.vaddr = sups->address;"; + s.op->newline() << "sup->up.vaddr = relocation + sups->address;"; s.op->newline() << "sup->up.handler = &enter_uprobe_probe;"; s.op->newline() << "rc = register_uprobe (& sup->up);"; s.op->newline(-1) << "}"; s.op->newline() << "if (rc) {"; // failed to register + s.op->newline() << "printk (KERN_WARNING \"uprobe failed pid %d addr %p rc %d\\n\", tsk->tgid, (void*)(relocation + sups->address), rc);"; s.op->newline(1) << "sup->spec_index = -1;"; s.op->newline(-1) << "} else {"; s.op->newline(1) << "handled_p = 1;"; // success @@ -6866,6 +6866,31 @@ uprobe_derived_probe_group::emit_module_decls (systemtap_session& s) s.op->newline(-1) << "}"; s.op->assert_0_indent(); + + // The task_finder_callback we use for ET_EXEC targets. + s.op->newline(); + s.op->newline() << "static int stap_uprobe_process_found (struct stap_task_finder_target *tgt, struct task_struct *tsk, int register_p, int process_p) {"; + + s.op->newline(1) << "struct stap_uprobe_spec *sups = container_of(tgt, struct stap_uprobe_spec, finder);"; + s.op->newline() << "if (! process_p) return 0;"; + s.op->newline(0) << "return stap_uprobe_change (tsk, register_p, 0, sups);"; + s.op->newline(-1) << "}"; + + // The task_finder_vm_callback we use for ET_DYN targets. + s.op->newline(); + s.op->newline() << "static int stap_uprobe_vmchange_found (struct stap_task_finder_target *tgt, struct task_struct *tsk, int map_p, char *vm_path, unsigned long vm_start, unsigned long vm_end, unsigned long vm_pgoff) {"; + s.op->newline(1) << "struct stap_uprobe_spec *sups = container_of(tgt, struct stap_uprobe_spec, finder);"; + // 1 - shared libraries' executable segments load from offset 0 - ld.so convention + s.op->newline() << "if (vm_pgoff != 0) return 0;"; + // 2 - the shared library we're interested in + s.op->newline() << "if (strcmp (vm_path, sups->pathname)) return 0;"; + // 3 - probe address within the mapping limits; test should not fail + s.op->newline() << "if (vm_end >= sups->address) return 0;"; + s.op->newline(0) << "return stap_uprobe_change (tsk, map_p, vm_start, sups);"; + s.op->newline(-1) << "}"; + s.op->assert_0_indent(); + + s.op->newline(); } @@ -6885,7 +6910,8 @@ uprobe_derived_probe_group::emit_module_init (systemtap_session& s) s.op->newline() << "for (i=0; i<" << probes.size() << "; i++) {"; s.op->newline(1) << "struct stap_uprobe_spec *sups = & stap_uprobe_specs[i];"; s.op->newline() << "probe_point = sups->pp;"; // for error messages - s.op->newline() << "sups->finder.callback = & stap_uprobe_process_found;"; + s.op->newline() << "if (sups->finder.pathname) sups->finder.callback = & stap_uprobe_process_found;"; + s.op->newline() << "else if (sups->pathname) sups->finder.vm_callback = & stap_uprobe_vmchange_found;"; s.op->newline() << "rc = stap_register_task_finder_target (& sups->finder);"; // NB: if (rc), there is no need (XXX: nor any way) to clean up any diff --git a/translate.cxx b/translate.cxx index 03ac0941..fc8a578e 100644 --- a/translate.cxx +++ b/translate.cxx @@ -4429,7 +4429,13 @@ dump_unwindsyms (Dwfl_Module *m, else if (n > 0) { assert (secname != NULL); - // secname adequately set + // secname adequately set + + // NB: it may be an empty string for ET_DYN objects + // like shared libraries, as their relocation base + // is implicit. + if (secname[0] == '\0') + secname = ".dynamic"; } else { |