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 // Copyright (c) 2007, Google Inc.

 // All rights reserved.

 //

 // Redistribution and use in source and binary forms, with or without

 // modification, are permitted provided that the following conditions are

 // met:

 //

 //     * Redistributions of source code must retain the above copyright

 // notice, this list of conditions and the following disclaimer.

 //     * Redistributions in binary form must reproduce the above

 // copyright notice, this list of conditions and the following disclaimer

 // in the documentation and/or other materials provided with the

 // distribution.

 //     * Neither the name of Google Inc. nor the names of its

 // contributors may be used to endorse or promote products derived from

 // this software without specific prior written permission.

 //

 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 // Author: Alfred Peng

 #include <dirent.h>

 #include <elf.h>

 #include <errno.h>

 #include <fcntl.h>

 #include <limits.h>

 #include <sys/frame.h>

 #include <sys/stat.h>

 #include <sys/types.h>

 #include <sys/wait.h>

 #include <unistd.h>

 #include <algorithm>

 #include <cassert>

 #include <cstdio>

 #include <cstdlib>

 #include <functional>

 #include "client/solaris/handler/solaris_lwp.h"

 #include "common/solaris/message_output.h"

 using namespace google_breakpad;

 // This unamed namespace contains helper function.

 namespace {

 uintptr_t stack_base_address = 0;

 static const int HEADER_MAX = 2000;

 static const int MAP_MAX = 1000;

 // Context information for the callbacks when validating address by listing

 // modules.

 struct AddressValidatingContext {

   uintptr_t address;

   bool is_mapped;

   AddressValidatingContext() : address(0UL), is_mapped(false) {

   }

 };

 // Convert from string to int.

 static bool LocalAtoi(char *s, int *r) {

   assert(s != NULL);

   assert(r != NULL);

   char *endptr = NULL;

   int ret = strtol(s, &endptr, 10);

   if (endptr == s)

     return false;

   *r = ret;

   return true;

 }

 // Callback invoked for each mapped module.

 // It uses the module's adderss range to validate the address.

 static bool AddressNotInModuleCallback(const ModuleInfo &module_info,

                                        void *context) {

   AddressValidatingContext *addr =

     reinterpret_cast<AddressValidatingContext *>(context);

   if (addr->is_mapped = ((module_info.start_addr > 0) &&

                          (addr->address >= module_info.start_addr) &&

                          (addr->address <= module_info.start_addr +

                           module_info.size))) {

     stack_base_address = module_info.start_addr + module_info.size;

   }

   return !addr->is_mapped;

 }

 static int IterateLwpAll(int pid,

                          CallbackParam<LwpidCallback> *callback_param) {

   char lwp_path[40];

   DIR *dir;

   int count = 0;

   snprintf(lwp_path, sizeof (lwp_path), "/proc/%d/lwp", (int)pid);

   if ((dir = opendir(lwp_path)) == NULL)

     return -1;

   struct dirent *entry = NULL;

   while ((entry = readdir(dir)) != NULL) {

     if ((strcmp(entry->d_name, ".") != 0) &&

         (strcmp(entry->d_name, "..") != 0)) {

       int lwpid = 0;

       int last_pid = 0;

       if (LocalAtoi(entry->d_name, &lwpid) && last_pid != lwpid) {

         last_pid = lwpid;

         ++count;

         if (callback_param &&

             !(callback_param->call_back)(lwpid, callback_param->context)) {

           break;

         }

       }

     }

   }

   closedir(dir);

   return count;

 }

 #if defined(__i386) && !defined(NO_FRAME_POINTER)

 void *GetNextFrame(void **last_ebp) {

   void *sp = *last_ebp;

   if ((unsigned long)sp == (unsigned long)last_ebp)

     return NULL;

   if ((unsigned long)sp & (sizeof(void *) - 1))

     return NULL;

   if ((unsigned long)sp - (unsigned long)last_ebp > 100000)

     return NULL;

   return sp;

 }

 #elif defined(__sparc)

 void *GetNextFrame(void *last_ebp) {

   return reinterpret_cast<struct frame *>(last_ebp)->fr_savfp;

 }

 #else

 void *GetNextFrame(void **last_ebp) {

   return reinterpret_cast<void*>(last_ebp);

 }

 #endif

 class AutoCloser {

  public:

   AutoCloser(int fd) : fd_(fd) {}

   ~AutoCloser() { if (fd_) close(fd_); }

  private:

   int fd_;

 };

 // Control the execution of the lwp.

 // Suspend/Resume lwp based on the value of context.

 static bool ControlLwp(int lwpid, void *context) {

   // The current thread is the one to handle the crash. Ignore it.

   if (lwpid != pthread_self()) {

     int ctlfd;

     char procname[PATH_MAX];

     bool suspend = *(bool *)context;

     // Open the /proc/$pid/lwp/$lwpid/lwpctl files

     snprintf(procname, sizeof (procname), "/proc/self/lwp/%d/lwpctl", lwpid);

     if ((ctlfd = open(procname, O_WRONLY|O_EXCL)) < 0) {

       print_message2(2, "failed to open %s in ControlLwp\n", procname);

       return false;

     }

     AutoCloser autocloser(ctlfd);

     long ctl[2];

     ctl[0] = suspend ? PCSTOP : PCRUN;

     ctl[1] = 0;

     if (write(ctlfd, ctl, sizeof (ctl)) != sizeof (ctl)) {

       print_message2(2, "failed in lwp %d\n", lwpid);

       return false;

     }

   }

   return true;

 }

 /*

  * Utility function to read the contents of a file that contains a

  * prheader_t at the start (/proc/$pid/lstatus or /proc/$pid/lpsinfo).

  * Return true on success.

  */

 static bool read_lfile(int pid, const char *lname, prheader_t *lhp) {

   char lpath[PATH_MAX];

   struct stat statb;

   int fd;

   size_t size;

   snprintf(lpath, sizeof (lpath), "/proc/%d/%s", pid, lname);

   if ((fd = open(lpath, O_RDONLY)) < 0) {

     print_message2(2, "failed to open %s in read_lfile\n", lpath);

     return false;

   }

   AutoCloser autocloser(fd);

   if (fstat(fd, &statb) != 0)

     return false;

   size = statb.st_size;

   if ((size / sizeof (prheader_t)) + 32 > HEADER_MAX) {

     print_message1(2, "map size overflow\n");

     return false;

   }

   if (pread(fd, lhp, size, 0) <= sizeof (prheader_t))

     return false;

   return true;

 }

 }  // namespace

 namespace google_breakpad {

 SolarisLwp::SolarisLwp(int pid) : pid_(pid) {

 }

 SolarisLwp::~SolarisLwp() {

 }

 int SolarisLwp::ControlAllLwps(bool suspend) {

   CallbackParam<LwpidCallback> callback_param(ControlLwp, &suspend);

   return IterateLwpAll(pid_, &callback_param);

 }

 int SolarisLwp::GetLwpCount() const {

   return IterateLwpAll(pid_, NULL);

 }

 int SolarisLwp::Lwp_iter_all(int pid,

                              CallbackParam<LwpCallback> *callback_param) const {

   lwpstatus_t *Lsp;

   lwpstatus_t *sp;

   prheader_t lphp[HEADER_MAX];

   prheader_t lhp[HEADER_MAX];

   prheader_t *Lphp = lphp;

   prheader_t *Lhp = lhp;

   lwpsinfo_t *Lpsp;

   long nstat;

   long ninfo;

   int rv = 0;

   /*

    * The /proc/pid/lstatus file has the array of lwpstatus_t's and the

    * /proc/pid/lpsinfo file has the array of lwpsinfo_t's.

    */

   if (read_lfile(pid, "lstatus", Lhp) == NULL)

     return -1;

   if (read_lfile(pid, "lpsinfo", Lphp) == NULL) {

     return -1;

   }

   Lsp = (lwpstatus_t *)(uintptr_t)(Lhp + 1);

   Lpsp = (lwpsinfo_t *)(uintptr_t)(Lphp + 1);

   for (ninfo = Lphp->pr_nent; ninfo != 0; --ninfo) {

     if (Lpsp->pr_sname != 'Z') {

       sp = Lsp;

       Lsp = (lwpstatus_t *)((uintptr_t)Lsp + Lhp->pr_entsize);

     } else {

       sp = NULL;

     }

     if (callback_param &&

         !(callback_param->call_back)(sp, callback_param->context))

       break;

     ++rv;

     Lpsp = (lwpsinfo_t *)((uintptr_t)Lpsp + Lphp->pr_entsize);

   }

   return rv;

 }

 uintptr_t SolarisLwp::GetLwpStackBottom(uintptr_t current_esp) const {

   AddressValidatingContext addr;

   addr.address = current_esp;

   CallbackParam<ModuleCallback> callback_param(AddressNotInModuleCallback,

                                                &addr);

   ListModules(&callback_param);

   return stack_base_address;

 }

 int SolarisLwp::GetModuleCount() const {

   return ListModules(NULL);

 }

 int SolarisLwp::ListModules(

     CallbackParam<ModuleCallback> *callback_param) const {

   const char *maps_path = "/proc/self/map";

   struct stat status;

   int fd = 0, num;

   prmap_t map_array[MAP_MAX];

   prmap_t *maps = map_array;

   size_t size;

   if ((fd = open(maps_path, O_RDONLY)) == -1) {

     print_message2(2, "failed to open %s in ListModules\n", maps_path);

     return -1;

   }

   AutoCloser autocloser(fd);

   if (fstat(fd, &status))

     return -1;

   /*

    * Determine number of mappings, this value must be 

    * larger than the actual module count

    */

   size = status.st_size;

   if ((num = (int)(size / sizeof (prmap_t))) > MAP_MAX) {

     print_message1(2, "map size overflow\n");

     return -1;

   }

   if (read(fd, (void *)maps, size) < 0) {

     print_message2(2, "failed to read %d\n", fd);

     return -1;

   }

   prmap_t *_maps;

   int _num;

   int module_count = 0;

   /*

    * Scan each mapping - note it is assummed that the mappings are

    * presented in order.  We fill holes between mappings.  On intel

    * the last mapping is usually the data segment of ld.so.1, after

    * this comes a red zone into which non-fixed mapping won't get

    * place.  Thus we can simply bail from the loop after seeing the

    * last mapping.

    */

   for (_num = 0, _maps = maps; _num < num; ++_num, ++_maps) {

     ModuleInfo module;

     char *name = _maps->pr_mapname;

     memset(&module, 0, sizeof (module));

     module.start_addr = _maps->pr_vaddr;

     module.size = _maps->pr_size;

     if (strlen(name) > 0) {

       int objectfd = 0;

       char path[PATH_MAX];

       char buf[SELFMAG];

       snprintf(path, sizeof (path), "/proc/self/object/%s", name);

       if ((objectfd = open(path, O_RDONLY)) < 0) {

         print_message1(2, "can't open module file\n");

         continue;

       }

       AutoCloser autocloser(objectfd);

       if (read(objectfd, buf, SELFMAG) != SELFMAG) {

         print_message1(2, "can't read module file\n");

         continue;

       }

       if (buf[0] != ELFMAG0 || buf[1] != ELFMAG1 ||

           buf[2] != ELFMAG2 || buf[3] != ELFMAG3) {

         continue;

       }

       strncpy(module.name, name, sizeof (module.name) - 1);

       ++module_count;

     }

     if (callback_param &&

         (!callback_param->call_back(module, callback_param->context))) {

       break;

     }

   }

   return module_count;

 }

 // Check if the address is a valid virtual address.

 // If the address is in any of the mapped modules, we take it as valid.

 // Otherwise it is invalid.

 bool SolarisLwp::IsAddressMapped(uintptr_t address) const {

   AddressValidatingContext addr;

   addr.address = address;

   CallbackParam<ModuleCallback> callback_param(AddressNotInModuleCallback,

                                                &addr);

   ListModules(&callback_param);

   return addr.is_mapped;

 }

 // We're looking for a ucontext_t as the second parameter

 // to a signal handler function call.  Luckily, the ucontext_t

 // has an ebp(fp on SPARC) member which should match the ebp(fp)

 // pointed to by the ebp(fp) of the signal handler frame.

 // The Solaris stack looks like this:

 // http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/lib/libproc/common/Pstack.c#81

 bool SolarisLwp::FindSigContext(uintptr_t sighandler_ebp,

                                 ucontext_t **sig_ctx) {

   uintptr_t previous_ebp;

   uintptr_t sig_ebp;

   const int MAX_STACK_DEPTH = 50;

   int depth_counter = 0;

   do {

 #if TARGET_CPU_SPARC

     previous_ebp = reinterpret_cast<uintptr_t>(GetNextFrame(

                                   reinterpret_cast<void*>(sighandler_ebp)));

     *sig_ctx = reinterpret_cast<ucontext_t*>(sighandler_ebp + sizeof (struct frame));

     uintptr_t sig_esp = (*sig_ctx)->uc_mcontext.gregs[REG_O6];

     if (sig_esp < previous_ebp && sig_esp > sighandler_ebp)

       sig_ebp = (uintptr_t)(((struct frame *)sig_esp)->fr_savfp);

 #elif TARGET_CPU_X86

     previous_ebp = reinterpret_cast<uintptr_t>(GetNextFrame(

                                   reinterpret_cast<void**>(sighandler_ebp)));

     *sig_ctx = reinterpret_cast<ucontext_t*>(sighandler_ebp + sizeof (struct frame) +

                                              3 * sizeof(uintptr_t));

     sig_ebp = (*sig_ctx)->uc_mcontext.gregs[EBP];

 #endif

     sighandler_ebp = previous_ebp;

     depth_counter++;

   } while(previous_ebp != sig_ebp && sighandler_ebp != 0 &&

           IsAddressMapped(sighandler_ebp) && depth_counter < MAX_STACK_DEPTH);

   return previous_ebp == sig_ebp && previous_ebp != 0;

 }

 }  // namespace google_breakpad