agent/src/os/bsd/libproc_impl.c

Wed, 13 Feb 2013 09:46:19 +0100

author
rbackman
date
Wed, 13 Feb 2013 09:46:19 +0100
changeset 4599
2394a89e89f4
parent 3156
f08d439fab8c
child 4750
39432a1cefdd
permissions
-rw-r--r--

8008088: SA can hang the VM
Reviewed-by: mgronlun, sla, dholmes

     1 /*
     2  * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    24 #include <stdarg.h>
    25 #include <stdio.h>
    26 #include <stdlib.h>
    27 #include <string.h>
    28 #include <fcntl.h>
    29 #include <thread_db.h>
    30 #include "libproc_impl.h"
    32 static const char* alt_root = NULL;
    33 static int alt_root_len = -1;
    35 #define SA_ALTROOT "SA_ALTROOT"
    37 static void init_alt_root() {
    38    if (alt_root_len == -1) {
    39       alt_root = getenv(SA_ALTROOT);
    40       if (alt_root) {
    41          alt_root_len = strlen(alt_root);
    42       } else {
    43          alt_root_len = 0;
    44       }
    45    }
    46 }
    48 int pathmap_open(const char* name) {
    49    int fd;
    50    char alt_path[PATH_MAX + 1];
    52    init_alt_root();
    53    fd = open(name, O_RDONLY);
    54    if (fd >= 0) {
    55       return fd;
    56    }
    58    if (alt_root_len > 0) {
    59       strcpy(alt_path, alt_root);
    60       strcat(alt_path, name);
    61       fd = open(alt_path, O_RDONLY);
    62       if (fd >= 0) {
    63          print_debug("path %s substituted for %s\n", alt_path, name);
    64          return fd;
    65       }
    67       if (strrchr(name, '/')) {
    68          strcpy(alt_path, alt_root);
    69          strcat(alt_path, strrchr(name, '/'));
    70          fd = open(alt_path, O_RDONLY);
    71          if (fd >= 0) {
    72             print_debug("path %s substituted for %s\n", alt_path, name);
    73             return fd;
    74          }
    75       }
    76    }
    78    return -1;
    79 }
    81 static bool _libsaproc_debug;
    83 void print_debug(const char* format,...) {
    84    if (_libsaproc_debug) {
    85      va_list alist;
    87      va_start(alist, format);
    88      fputs("libsaproc DEBUG: ", stderr);
    89      vfprintf(stderr, format, alist);
    90      va_end(alist);
    91    }
    92 }
    94 void print_error(const char* format,...) {
    95   va_list alist;
    96   va_start(alist, format);
    97   fputs("ERROR: ", stderr);
    98   vfprintf(stderr, format, alist);
    99   va_end(alist);
   100 }
   102 bool is_debug() {
   103    return _libsaproc_debug;
   104 }
   106 // initialize libproc
   107 bool init_libproc(bool debug) {
   108    // init debug mode
   109    _libsaproc_debug = debug;
   111    // initialize the thread_db library
   112    if (td_init() != TD_OK) {
   113      print_debug("libthread_db's td_init failed\n");
   114      return false;
   115    }
   117    return true;
   118 }
   120 static void destroy_lib_info(struct ps_prochandle* ph) {
   121    lib_info* lib = ph->libs;
   122    while (lib) {
   123      lib_info *next = lib->next;
   124      if (lib->symtab) {
   125         destroy_symtab(lib->symtab);
   126      }
   127      free(lib);
   128      lib = next;
   129    }
   130 }
   132 static void destroy_thread_info(struct ps_prochandle* ph) {
   133    thread_info* thr = ph->threads;
   134    while (thr) {
   135      thread_info *next = thr->next;
   136      free(thr);
   137      thr = next;
   138    }
   139 }
   141 // ps_prochandle cleanup
   143 // ps_prochandle cleanup
   144 void Prelease(struct ps_prochandle* ph) {
   145    // do the "derived class" clean-up first
   146    ph->ops->release(ph);
   147    destroy_lib_info(ph);
   148    destroy_thread_info(ph);
   149    free(ph);
   150 }
   152 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) {
   153    return add_lib_info_fd(ph, libname, -1, base);
   154 }
   156 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) {
   157    lib_info* newlib;
   159    if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) {
   160       print_debug("can't allocate memory for lib_info\n");
   161       return NULL;
   162    }
   164    strncpy(newlib->name, libname, sizeof(newlib->name));
   165    newlib->base = base;
   167    if (fd == -1) {
   168       if ( (newlib->fd = pathmap_open(newlib->name)) < 0) {
   169          print_debug("can't open shared object %s\n", newlib->name);
   170          free(newlib);
   171          return NULL;
   172       }
   173    } else {
   174       newlib->fd = fd;
   175    }
   177    // check whether we have got an ELF file. /proc/<pid>/map
   178    // gives out all file mappings and not just shared objects
   179    if (is_elf_file(newlib->fd) == false) {
   180       close(newlib->fd);
   181       free(newlib);
   182       return NULL;
   183    }
   185    newlib->symtab = build_symtab(newlib->fd);
   186    if (newlib->symtab == NULL) {
   187       print_debug("symbol table build failed for %s\n", newlib->name);
   188    }
   189    else {
   190       print_debug("built symbol table for %s\n", newlib->name);
   191    }
   193    // even if symbol table building fails, we add the lib_info.
   194    // This is because we may need to read from the ELF file for core file
   195    // address read functionality. lookup_symbol checks for NULL symtab.
   196    if (ph->libs) {
   197       ph->lib_tail->next = newlib;
   198       ph->lib_tail = newlib;
   199    }  else {
   200       ph->libs = ph->lib_tail = newlib;
   201    }
   202    ph->num_libs++;
   204    return newlib;
   205 }
   207 // lookup for a specific symbol
   208 uintptr_t lookup_symbol(struct ps_prochandle* ph,  const char* object_name,
   209                        const char* sym_name) {
   210    // ignore object_name. search in all libraries
   211    // FIXME: what should we do with object_name?? The library names are obtained
   212    // by parsing /proc/<pid>/maps, which may not be the same as object_name.
   213    // What we need is a utility to map object_name to real file name, something
   214    // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For
   215    // now, we just ignore object_name and do a global search for the symbol.
   217    lib_info* lib = ph->libs;
   218    while (lib) {
   219       if (lib->symtab) {
   220          uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL);
   221          if (res) return res;
   222       }
   223       lib = lib->next;
   224    }
   226    print_debug("lookup failed for symbol '%s' in obj '%s'\n",
   227                           sym_name, object_name);
   228    return (uintptr_t) NULL;
   229 }
   232 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) {
   233    const char* res = NULL;
   234    lib_info* lib = ph->libs;
   235    while (lib) {
   236       if (lib->symtab && addr >= lib->base) {
   237          res = nearest_symbol(lib->symtab, addr - lib->base, poffset);
   238          if (res) return res;
   239       }
   240       lib = lib->next;
   241    }
   242    return NULL;
   243 }
   245 // add a thread to ps_prochandle
   246 thread_info* add_thread_info(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) {
   247    thread_info* newthr;
   248    if ( (newthr = (thread_info*) calloc(1, sizeof(thread_info))) == NULL) {
   249       print_debug("can't allocate memory for thread_info\n");
   250       return NULL;
   251    }
   253    // initialize thread info
   254    newthr->pthread_id = pthread_id;
   255    newthr->lwp_id = lwp_id;
   257    // add new thread to the list
   258    newthr->next = ph->threads;
   259    ph->threads = newthr;
   260    ph->num_threads++;
   261    return newthr;
   262 }
   265 // struct used for client data from thread_db callback
   266 struct thread_db_client_data {
   267    struct ps_prochandle* ph;
   268    thread_info_callback callback;
   269 };
   271 // callback function for libthread_db
   272 static int thread_db_callback(const td_thrhandle_t *th_p, void *data) {
   273   struct thread_db_client_data* ptr = (struct thread_db_client_data*) data;
   274   td_thrinfo_t ti;
   275   td_err_e err;
   277   memset(&ti, 0, sizeof(ti));
   278   err = td_thr_get_info(th_p, &ti);
   279   if (err != TD_OK) {
   280     print_debug("libthread_db : td_thr_get_info failed, can't get thread info\n");
   281     return err;
   282   }
   284   print_debug("thread_db : pthread %d (lwp %d)\n", ti.ti_tid, ti.ti_lid);
   286   if (ptr->callback(ptr->ph, (pthread_t)ti.ti_tid, ti.ti_lid) != true)
   287     return TD_ERR;
   289   return TD_OK;
   290 }
   292 // read thread_info using libthread_db
   293 bool read_thread_info(struct ps_prochandle* ph, thread_info_callback cb) {
   294   struct thread_db_client_data mydata;
   295   td_thragent_t* thread_agent = NULL;
   296   if (td_ta_new(ph, &thread_agent) != TD_OK) {
   297      print_debug("can't create libthread_db agent\n");
   298      return false;
   299   }
   301   mydata.ph = ph;
   302   mydata.callback = cb;
   304   // we use libthread_db iterator to iterate thru list of threads.
   305   if (td_ta_thr_iter(thread_agent, thread_db_callback, &mydata,
   306                  TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,
   307                  TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS) != TD_OK) {
   308      td_ta_delete(thread_agent);
   309      return false;
   310   }
   312   // delete thread agent
   313   td_ta_delete(thread_agent);
   314   return true;
   315 }
   318 // get number of threads
   319 int get_num_threads(struct ps_prochandle* ph) {
   320    return ph->num_threads;
   321 }
   323 // get lwp_id of n'th thread
   324 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) {
   325    int count = 0;
   326    thread_info* thr = ph->threads;
   327    while (thr) {
   328       if (count == index) {
   329          return thr->lwp_id;
   330       }
   331       count++;
   332       thr = thr->next;
   333    }
   334    return -1;
   335 }
   337 // get regs for a given lwp
   338 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct reg* regs) {
   339   return ph->ops->get_lwp_regs(ph, lwp_id, regs);
   340 }
   342 // get number of shared objects
   343 int get_num_libs(struct ps_prochandle* ph) {
   344    return ph->num_libs;
   345 }
   347 // get name of n'th solib
   348 const char* get_lib_name(struct ps_prochandle* ph, int index) {
   349    int count = 0;
   350    lib_info* lib = ph->libs;
   351    while (lib) {
   352       if (count == index) {
   353          return lib->name;
   354       }
   355       count++;
   356       lib = lib->next;
   357    }
   358    return NULL;
   359 }
   361 // get base address of a lib
   362 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) {
   363    int count = 0;
   364    lib_info* lib = ph->libs;
   365    while (lib) {
   366       if (count == index) {
   367          return lib->base;
   368       }
   369       count++;
   370       lib = lib->next;
   371    }
   372    return (uintptr_t)NULL;
   373 }
   375 bool find_lib(struct ps_prochandle* ph, const char *lib_name) {
   376   lib_info *p = ph->libs;
   377   while (p) {
   378     if (strcmp(p->name, lib_name) == 0) {
   379       return true;
   380     }
   381     p = p->next;
   382   }
   383   return false;
   384 }
   386 //--------------------------------------------------------------------------
   387 // proc service functions
   389 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table
   390 // of the load object object_name in the target process identified by ph.
   391 // It returns the symbol's value as an address in the target process in
   392 // *sym_addr.
   394 ps_err_e ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name,
   395                     const char *sym_name, psaddr_t *sym_addr) {
   396   *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name);
   397   return (*sym_addr ? PS_OK : PS_NOSYM);
   398 }
   400 // read "size" bytes info "buf" from address "addr"
   401 ps_err_e ps_pread(struct ps_prochandle *ph, psaddr_t  addr,
   402                   void *buf, size_t size) {
   403   return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR;
   404 }
   406 // write "size" bytes of data to debuggee at address "addr"
   407 ps_err_e ps_pwrite(struct ps_prochandle *ph, psaddr_t addr,
   408                    const void *buf, size_t size) {
   409   return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR;
   410 }
   412 // fill in ptrace_lwpinfo for lid
   413 ps_err_e ps_linfo(struct ps_prochandle *ph, lwpid_t lwp_id, void *linfo) {
   414   return ph->ops->get_lwp_info(ph, lwp_id, linfo)? PS_OK: PS_ERR;
   415 }
   417 // needed for when libthread_db is compiled with TD_DEBUG defined
   418 void
   419 ps_plog (const char *format, ...)
   420 {
   421   va_list alist;
   423   va_start(alist, format);
   424   vfprintf(stderr, format, alist);
   425   va_end(alist);
   426 }
   428 // ------------------------------------------------------------------------
   429 // Functions below this point are not yet implemented. They are here only
   430 // to make the linker happy.
   432 ps_err_e ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) {
   433   print_debug("ps_lsetfpregs not implemented\n");
   434   return PS_OK;
   435 }
   437 ps_err_e ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) {
   438   print_debug("ps_lsetregs not implemented\n");
   439   return PS_OK;
   440 }
   442 ps_err_e  ps_lgetfpregs(struct  ps_prochandle  *ph,  lwpid_t lid, prfpregset_t *fpregs) {
   443   print_debug("ps_lgetfpregs not implemented\n");
   444   return PS_OK;
   445 }
   447 ps_err_e ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) {
   448   print_debug("ps_lgetfpregs not implemented\n");
   449   return PS_OK;
   450 }
   452 ps_err_e ps_lstop(struct ps_prochandle *ph, lwpid_t lid) {
   453   print_debug("ps_lstop not implemented\n");
   454   return PS_OK;
   455 }
   457 ps_err_e ps_pcontinue(struct ps_prochandle *ph) {
   458   print_debug("ps_pcontinue not implemented\n");
   459   return PS_OK;
   460 }

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