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 "libproc_impl.h"

    25 

    26 static const char* alt_root = NULL;

    27 static int alt_root_len = -1;

    28 

    29 #define SA_ALTROOT "SA_ALTROOT"

    30 

    31 off_t ltell(int fd) {

    32   return lseek(fd, 0, SEEK_CUR);

    33 }

    34 

    35 static void init_alt_root() {

    36   if (alt_root_len == -1) {

    37     alt_root = getenv(SA_ALTROOT);

    38     if (alt_root) {

    39       alt_root_len = strlen(alt_root);

    40     } else {

    41       alt_root_len = 0;

    42     }

    43   }

    44 }

    45 

    46 int pathmap_open(const char* name) {

    47   int fd;

    48   char alt_path[PATH_MAX + 1];

    49 

    50   init_alt_root();

    51 

    52   if (alt_root_len > 0) {

    53     strcpy(alt_path, alt_root);

    54     strcat(alt_path, name);

    55     fd = open(alt_path, O_RDONLY);

    56     if (fd >= 0) {

    57       print_debug("path %s substituted for %s\n", alt_path, name);

    58       return fd;

    59     }

    60 

    61     if (strrchr(name, '/')) {

    62       strcpy(alt_path, alt_root);

    63       strcat(alt_path, strrchr(name, '/'));

    64       fd = open(alt_path, O_RDONLY);

    65       if (fd >= 0) {

    66         print_debug("path %s substituted for %s\n", alt_path, name);

    67         return fd;

    68       }

    69     }

    70   } else {

    71     fd = open(name, O_RDONLY);

    72     if (fd >= 0) {

    73       return fd;

    74     }

    75   }

    76   return -1;

    77 }

    78 

    79 static bool _libsaproc_debug;

    80 

    81 void print_debug(const char* format,...) {

    82   if (_libsaproc_debug) {

    83     va_list alist;

    84 

    85     va_start(alist, format);

    86     fputs("libsaproc DEBUG: ", stderr);

    87     vfprintf(stderr, format, alist);

    88     va_end(alist);

    89   }

    90 }

    91 

    92 void print_error(const char* format,...) {

    93   va_list alist;

    94   va_start(alist, format);

    95   fputs("ERROR: ", stderr);

    96   vfprintf(stderr, format, alist);

    97   va_end(alist);

    98 }

    99 

   100 bool is_debug() {

   101   return _libsaproc_debug;

   102 }

   103 

   104 #ifdef __APPLE__

   105 // get arch offset in file

   106 bool get_arch_off(int fd, cpu_type_t cputype, off_t *offset) {

   107   struct fat_header fatheader;

   108   struct fat_arch fatarch;

   109   off_t img_start = 0;

   110 

   111   off_t pos = ltell(fd);

   112   if (read(fd, (void *)&fatheader, sizeof(struct fat_header)) != sizeof(struct fat_header)) {

   113     return false;

   114   }

   115   if (fatheader.magic == FAT_CIGAM) {

   116     int i;

   117     for (i = 0; i < ntohl(fatheader.nfat_arch); i++) {

   118       if (read(fd, (void *)&fatarch, sizeof(struct fat_arch)) != sizeof(struct fat_arch)) {

   119         return false;

   120       }

   121       if (ntohl(fatarch.cputype) == cputype) {

   122         print_debug("fat offset=%x\n", ntohl(fatarch.offset));

   123         img_start = ntohl(fatarch.offset);

   124         break;

   125       }

   126     }

   127     if (img_start == 0) {

   128       return false;

   129     }

   130   }

   131   lseek(fd, pos, SEEK_SET);

   132   *offset = img_start;

   133   return true;

   134 }

   135 

   136 bool is_macho_file(int fd) {

   137   mach_header_64 fhdr;

   138   off_t x86_64_off;

   139 

   140   if (fd < 0) {

   141     print_debug("Invalid file handle passed to is_macho_file\n");

   142     return false;

   143   }

   144 

   145   off_t pos = ltell(fd);

   146   // check fat header

   147   if (!get_arch_off(fd, CPU_TYPE_X86_64, &x86_64_off)) {

   148     print_debug("failed to get fat header\n");

   149     return false;

   150   }

   151   lseek(fd, x86_64_off, SEEK_SET);

   152   if (read(fd, (void *)&fhdr, sizeof(mach_header_64)) != sizeof(mach_header_64)) {

   153      return false;

   154   }

   155   lseek(fd, pos, SEEK_SET);               // restore

   156   print_debug("fhdr.magic %x\n", fhdr.magic);

   157   return (fhdr.magic == MH_MAGIC_64 || fhdr.magic == MH_CIGAM_64);

   158 }

   159 

   160 #endif //__APPLE__

   161 

   162 // initialize libproc

   163 bool init_libproc(bool debug) {

   164    _libsaproc_debug = debug;

   165 #ifndef __APPLE__

   166    // initialize the thread_db library

   167    if (td_init() != TD_OK) {

   168      print_debug("libthread_db's td_init failed\n");

   169      return false;

   170    }

   171 #endif // __APPLE__

   172    return true;

   173 }

   174 

   175 void destroy_lib_info(struct ps_prochandle* ph) {

   176   lib_info* lib = ph->libs;

   177   while (lib) {

   178     lib_info* next = lib->next;

   179     if (lib->symtab) {

   180       destroy_symtab(lib->symtab);

   181     }

   182     free(lib);

   183     lib = next;

   184   }

   185 }

   186 

   187 void destroy_thread_info(struct ps_prochandle* ph) {

   188   sa_thread_info* thr = ph->threads;

   189   while (thr) {

   190     sa_thread_info* n = thr->next;

   191     free(thr);

   192     thr = n;

   193   }

   194 }

   195 

   196 // ps_prochandle cleanup

   197 void Prelease(struct ps_prochandle* ph) {

   198   // do the "derived class" clean-up first

   199   ph->ops->release(ph);

   200   destroy_lib_info(ph);

   201   destroy_thread_info(ph);

   202   free(ph);

   203 }

   204 

   205 lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) {

   206   return add_lib_info_fd(ph, libname, -1, base);

   207 }

   208 

   209 lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) {

   210    lib_info* newlib;

   211   print_debug("add_lib_info_fd %s\n", libname);

   212 

   213   if ( (newlib = (lib_info*) calloc(1, sizeof(struct lib_info))) == NULL) {

   214     print_debug("can't allocate memory for lib_info\n");

   215     return NULL;

   216   }

   217 

   218   if (strlen(libname) >= sizeof(newlib->name)) {

   219     print_debug("libname %s too long\n", libname);

   220     free(newlib);

   221     return NULL;

   222   }

   223   strcpy(newlib->name, libname);

   224 

   225   newlib->base = base;

   226 

   227   if (fd == -1) {

   228     if ( (newlib->fd = pathmap_open(newlib->name)) < 0) {

   229       print_debug("can't open shared object %s\n", newlib->name);

   230       free(newlib);

   231       return NULL;

   232     }

   233   } else {

   234     newlib->fd = fd;

   235   }

   236 

   237 #ifdef __APPLE__

   238   // check whether we have got an Macho file.

   239   if (is_macho_file(newlib->fd) == false) {

   240     close(newlib->fd);

   241     free(newlib);

   242     print_debug("not a mach-o file\n");

   243     return NULL;

   244   }

   245 #else

   246   // check whether we have got an ELF file. /proc/<pid>/map

   247   // gives out all file mappings and not just shared objects

   248   if (is_elf_file(newlib->fd) == false) {

   249     close(newlib->fd);

   250     free(newlib);

   251     return NULL;

   252   }

   253 #endif // __APPLE__

   254 

   255   newlib->symtab = build_symtab(newlib->fd);

   256   if (newlib->symtab == NULL) {

   257     print_debug("symbol table build failed for %s\n", newlib->name);

   258   } else {

   259     print_debug("built symbol table for %s\n", newlib->name);

   260   }

   261 

   262   // even if symbol table building fails, we add the lib_info.

   263   // This is because we may need to read from the ELF file or MachO file for core file

   264   // address read functionality. lookup_symbol checks for NULL symtab.

   265   if (ph->libs) {

   266     ph->lib_tail->next = newlib;

   267     ph->lib_tail = newlib;

   268   }  else {

   269     ph->libs = ph->lib_tail = newlib;

   270   }

   271   ph->num_libs++;

   272   return newlib;

   273 }

   274 

   275 // lookup for a specific symbol

   276 uintptr_t lookup_symbol(struct ps_prochandle* ph,  const char* object_name,

   277                        const char* sym_name) {

   278   // ignore object_name. search in all libraries

   279   // FIXME: what should we do with object_name?? The library names are obtained

   280   // by parsing /proc/<pid>/maps, which may not be the same as object_name.

   281   // What we need is a utility to map object_name to real file name, something

   282   // dlopen() does by looking at LD_LIBRARY_PATH and /etc/ld.so.cache. For

   283   // now, we just ignore object_name and do a global search for the symbol.

   284 

   285   lib_info* lib = ph->libs;

   286   while (lib) {

   287     if (lib->symtab) {

   288       uintptr_t res = search_symbol(lib->symtab, lib->base, sym_name, NULL);

   289       if (res) return res;

   290     }

   291     lib = lib->next;

   292   }

   293 

   294   print_debug("lookup failed for symbol '%s' in obj '%s'\n",

   295                           sym_name, object_name);

   296   return (uintptr_t) NULL;

   297 }

   298 

   299 const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) {

   300   const char* res = NULL;

   301   lib_info* lib = ph->libs;

   302   while (lib) {

   303     if (lib->symtab && addr >= lib->base) {

   304       res = nearest_symbol(lib->symtab, addr - lib->base, poffset);

   305       if (res) return res;

   306     }

   307     lib = lib->next;

   308   }

   309   return NULL;

   310 }

   311 

   312 // add a thread to ps_prochandle

   313 sa_thread_info* add_thread_info(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id) {

   314   sa_thread_info* newthr;

   315   if ( (newthr = (sa_thread_info*) calloc(1, sizeof(sa_thread_info))) == NULL) {

   316     print_debug("can't allocate memory for thread_info\n");

   317     return NULL;

   318   }

   319 

   320   // initialize thread info

   321   newthr->pthread_id = pthread_id;

   322   newthr->lwp_id = lwp_id;

   323 

   324   // add new thread to the list

   325   newthr->next = ph->threads;

   326   ph->threads = newthr;

   327   ph->num_threads++;

   328   return newthr;

   329 }

   330 

   331 #ifndef __APPLE__

   332 // struct used for client data from thread_db callback

   333 struct thread_db_client_data {

   334   struct ps_prochandle* ph;

   335   thread_info_callback callback;

   336 };

   337 

   338 // callback function for libthread_db

   339 static int thread_db_callback(const td_thrhandle_t *th_p, void *data) {

   340   struct thread_db_client_data* ptr = (struct thread_db_client_data*) data;

   341   td_thrinfo_t ti;

   342   td_err_e err;

   343 

   344   memset(&ti, 0, sizeof(ti));

   345   err = td_thr_get_info(th_p, &ti);

   346   if (err != TD_OK) {

   347     print_debug("libthread_db : td_thr_get_info failed, can't get thread info\n");

   348     return err;

   349   }

   350 

   351   print_debug("thread_db : pthread %d (lwp %d)\n", ti.ti_tid, ti.ti_lid);

   352 

   353   if (ptr->callback(ptr->ph, (pthread_t)ti.ti_tid, ti.ti_lid) != true)

   354     return TD_ERR;

   355 

   356   return TD_OK;

   357 }

   358 

   359 // read thread_info using libthread_db

   360 bool read_thread_info(struct ps_prochandle* ph, thread_info_callback cb) {

   361   struct thread_db_client_data mydata;

   362   td_thragent_t* thread_agent = NULL;

   363   if (td_ta_new(ph, &thread_agent) != TD_OK) {

   364      print_debug("can't create libthread_db agent\n");

   365      return false;

   366   }

   367 

   368   mydata.ph = ph;

   369   mydata.callback = cb;

   370 

   371   // we use libthread_db iterator to iterate thru list of threads.

   372   if (td_ta_thr_iter(thread_agent, thread_db_callback, &mydata,

   373                  TD_THR_ANY_STATE, TD_THR_LOWEST_PRIORITY,

   374                  TD_SIGNO_MASK, TD_THR_ANY_USER_FLAGS) != TD_OK) {

   375      td_ta_delete(thread_agent);

   376      return false;

   377   }

   378 

   379   // delete thread agent

   380   td_ta_delete(thread_agent);

   381   return true;

   382 }

   383 

   384 #endif // __APPLE__

   385 

   386 // get number of threads

   387 int get_num_threads(struct ps_prochandle* ph) {

   388    return ph->num_threads;

   389 }

   390 

   391 // get lwp_id of n'th thread

   392 lwpid_t get_lwp_id(struct ps_prochandle* ph, int index) {

   393   int count = 0;

   394   sa_thread_info* thr = ph->threads;

   395   while (thr) {

   396     if (count == index) {

   397       return thr->lwp_id;

   398     }

   399     count++;

   400     thr = thr->next;

   401   }

   402   return 0;

   403 }

   404 

   405 #ifdef __APPLE__

   406 // set lwp_id of n'th thread

   407 bool set_lwp_id(struct ps_prochandle* ph, int index, lwpid_t lwpid) {

   408   int count = 0;

   409   sa_thread_info* thr = ph->threads;

   410   while (thr) {

   411     if (count == index) {

   412       thr->lwp_id = lwpid;

   413       return true;

   414     }

   415     count++;

   416     thr = thr->next;

   417   }

   418   return false;

   419 }

   420 

   421 // get regs of n-th thread, only used in fillThreads the first time called

   422 bool get_nth_lwp_regs(struct ps_prochandle* ph, int index, struct reg* regs) {

   423   int count = 0;

   424   sa_thread_info* thr = ph->threads;

   425   while (thr) {

   426     if (count == index) {

   427       break;

   428     }

   429     count++;

   430     thr = thr->next;

   431   }

   432   if (thr != NULL) {

   433     memcpy(regs, &thr->regs, sizeof(struct reg));

   434     return true;

   435   }

   436   return false;

   437 }

   438 

   439 #endif // __APPLE__

   440 

   441 // get regs for a given lwp

   442 bool get_lwp_regs(struct ps_prochandle* ph, lwpid_t lwp_id, struct reg* regs) {

   443   return ph->ops->get_lwp_regs(ph, lwp_id, regs);

   444 }

   445 

   446 // get number of shared objects

   447 int get_num_libs(struct ps_prochandle* ph) {

   448   return ph->num_libs;

   449 }

   450 

   451 // get name of n'th solib

   452 const char* get_lib_name(struct ps_prochandle* ph, int index) {

   453   int count = 0;

   454   lib_info* lib = ph->libs;

   455   while (lib) {

   456     if (count == index) {

   457       return lib->name;

   458     }

   459     count++;

   460     lib = lib->next;

   461   }

   462   return NULL;

   463 }

   464 

   465 // get base address of a lib

   466 uintptr_t get_lib_base(struct ps_prochandle* ph, int index) {

   467   int count = 0;

   468   lib_info* lib = ph->libs;

   469   while (lib) {

   470     if (count == index) {

   471       return lib->base;

   472     }

   473     count++;

   474     lib = lib->next;

   475   }

   476   return (uintptr_t)NULL;

   477 }

   478 

   479 bool find_lib(struct ps_prochandle* ph, const char *lib_name) {

   480   lib_info *p = ph->libs;

   481   while (p) {

   482     if (strcmp(p->name, lib_name) == 0) {

   483       return true;

   484     }

   485     p = p->next;

   486   }

   487   return false;

   488 }

   489 

   490 //--------------------------------------------------------------------------

   491 // proc service functions

   492 

   493 // ps_pglobal_lookup() looks up the symbol sym_name in the symbol table

   494 // of the load object object_name in the target process identified by ph.

   495 // It returns the symbol's value as an address in the target process in

   496 // *sym_addr.

   497 

   498 ps_err_e ps_pglobal_lookup(struct ps_prochandle *ph, const char *object_name,

   499                     const char *sym_name, psaddr_t *sym_addr) {

   500   *sym_addr = (psaddr_t) lookup_symbol(ph, object_name, sym_name);

   501   return (*sym_addr ? PS_OK : PS_NOSYM);

   502 }

   503 

   504 // read "size" bytes info "buf" from address "addr"

   505 ps_err_e ps_pread(struct ps_prochandle *ph, psaddr_t  addr,

   506                   void *buf, size_t size) {

   507   return ph->ops->p_pread(ph, (uintptr_t) addr, buf, size)? PS_OK: PS_ERR;

   508 }

   509 

   510 // write "size" bytes of data to debuggee at address "addr"

   511 ps_err_e ps_pwrite(struct ps_prochandle *ph, psaddr_t addr,

   512                    const void *buf, size_t size) {

   513   return ph->ops->p_pwrite(ph, (uintptr_t)addr, buf, size)? PS_OK: PS_ERR;

   514 }

   515 

   516 // fill in ptrace_lwpinfo for lid

   517 ps_err_e ps_linfo(struct ps_prochandle *ph, lwpid_t lwp_id, void *linfo) {

   518   return ph->ops->get_lwp_info(ph, lwp_id, linfo)? PS_OK: PS_ERR;

   519 }

   520 

   521 // needed for when libthread_db is compiled with TD_DEBUG defined

   522 void

   523 ps_plog (const char *format, ...)

   524 {

   525   va_list alist;

   526 

   527   va_start(alist, format);

   528   vfprintf(stderr, format, alist);

   529   va_end(alist);

   530 }

   531 

   532 #ifndef __APPLE__

   533 // ------------------------------------------------------------------------

   534 // Functions below this point are not yet implemented. They are here only

   535 // to make the linker happy.

   536 

   537 ps_err_e ps_lsetfpregs(struct ps_prochandle *ph, lwpid_t lid, const prfpregset_t *fpregs) {

   538   print_debug("ps_lsetfpregs not implemented\n");

   539   return PS_OK;

   540 }

   541 

   542 ps_err_e ps_lsetregs(struct ps_prochandle *ph, lwpid_t lid, const prgregset_t gregset) {

   543   print_debug("ps_lsetregs not implemented\n");

   544   return PS_OK;

   545 }

   546 

   547 ps_err_e  ps_lgetfpregs(struct  ps_prochandle  *ph,  lwpid_t lid, prfpregset_t *fpregs) {

   548   print_debug("ps_lgetfpregs not implemented\n");

   549   return PS_OK;

   550 }

   551 

   552 ps_err_e ps_lgetregs(struct ps_prochandle *ph, lwpid_t lid, prgregset_t gregset) {

   553   print_debug("ps_lgetfpregs not implemented\n");

   554   return PS_OK;

   555 }

   556 

   557 ps_err_e ps_lstop(struct ps_prochandle *ph, lwpid_t lid) {

   558   print_debug("ps_lstop not implemented\n");

   559   return PS_OK;

   560 }

   561 

   562 ps_err_e ps_pcontinue(struct ps_prochandle *ph) {

   563   print_debug("ps_pcontinue not implemented\n");

   564   return PS_OK;

   565 }

   566 #endif // __APPLE__