| // Copyright 2012 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Platform-specific code for Linux goes here. For the POSIX-compatible |
| // parts, the implementation is in platform-posix.cc. |
| |
| #include <pthread.h> |
| #include <semaphore.h> |
| #include <signal.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <sys/prctl.h> |
| #include <sys/resource.h> |
| #include <sys/syscall.h> |
| #include <sys/time.h> |
| |
| // Ubuntu Dapper requires memory pages to be marked as |
| // executable. Otherwise, OS raises an exception when executing code |
| // in that page. |
| #include <errno.h> |
| #include <fcntl.h> // open |
| #include <stdarg.h> |
| #include <strings.h> // index |
| #include <sys/mman.h> // mmap & munmap & mremap |
| #include <sys/stat.h> // open |
| #include <sys/types.h> // mmap & munmap |
| #include <unistd.h> // sysconf |
| |
| #include <cmath> |
| |
| #undef MAP_TYPE |
| |
| #include "src/base/macros.h" |
| #include "src/base/platform/platform-posix-time.h" |
| #include "src/base/platform/platform-posix.h" |
| #include "src/base/platform/platform.h" |
| |
| namespace v8 { |
| namespace base { |
| |
| TimezoneCache* OS::CreateTimezoneCache() { |
| return new PosixDefaultTimezoneCache(); |
| } |
| |
| std::vector<OS::SharedLibraryAddress> OS::GetSharedLibraryAddresses() { |
| std::vector<SharedLibraryAddress> result; |
| // This function assumes that the layout of the file is as follows: |
| // hex_start_addr-hex_end_addr rwxp <unused data> [binary_file_name] |
| // If we encounter an unexpected situation we abort scanning further entries. |
| FILE* fp = fopen("/proc/self/maps", "r"); |
| if (fp == nullptr) return result; |
| |
| // Allocate enough room to be able to store a full file name. |
| const int kLibNameLen = FILENAME_MAX + 1; |
| char* lib_name = reinterpret_cast<char*>(malloc(kLibNameLen)); |
| |
| // This loop will terminate once the scanning hits an EOF. |
| while (true) { |
| uintptr_t start, end, offset; |
| char attr_r, attr_w, attr_x, attr_p; |
| // Parse the addresses and permission bits at the beginning of the line. |
| if (fscanf(fp, "%" V8PRIxPTR "-%" V8PRIxPTR, &start, &end) != 2) break; |
| if (fscanf(fp, " %c%c%c%c", &attr_r, &attr_w, &attr_x, &attr_p) != 4) break; |
| if (fscanf(fp, "%" V8PRIxPTR, &offset) != 1) break; |
| |
| int c; |
| if (attr_r == 'r' && attr_w != 'w' && attr_x == 'x') { |
| // Found a read-only executable entry. Skip characters until we reach |
| // the beginning of the filename or the end of the line. |
| do { |
| c = getc(fp); |
| } while ((c != EOF) && (c != '\n') && (c != '/') && (c != '[')); |
| if (c == EOF) break; // EOF: Was unexpected, just exit. |
| |
| // Process the filename if found. |
| if ((c == '/') || (c == '[')) { |
| // Push the '/' or '[' back into the stream to be read below. |
| ungetc(c, fp); |
| |
| // Read to the end of the line. Exit if the read fails. |
| if (fgets(lib_name, kLibNameLen, fp) == nullptr) break; |
| |
| // Drop the newline character read by fgets. We do not need to check |
| // for a zero-length string because we know that we at least read the |
| // '/' or '[' character. |
| lib_name[strlen(lib_name) - 1] = '\0'; |
| } else { |
| // No library name found, just record the raw address range. |
| snprintf(lib_name, kLibNameLen, "%08" V8PRIxPTR "-%08" V8PRIxPTR, start, |
| end); |
| } |
| |
| #ifdef V8_OS_ANDROID |
| size_t lib_name_length = strlen(lib_name); |
| if (lib_name_length < 4 || |
| strncmp(&lib_name[lib_name_length - 4], ".apk", 4) != 0) { |
| // Only adjust {start} based on {offset} if the file isn't the APK, |
| // since we load the library directly from the APK and don't want to |
| // apply the offset of the .so in the APK as the libraries offset. |
| start -= offset; |
| } |
| #else |
| // Adjust {start} based on {offset}. |
| start -= offset; |
| #endif |
| |
| result.push_back(SharedLibraryAddress(lib_name, start, end)); |
| } else { |
| // Entry not describing executable data. Skip to end of line to set up |
| // reading the next entry. |
| do { |
| c = getc(fp); |
| } while ((c != EOF) && (c != '\n')); |
| if (c == EOF) break; |
| } |
| } |
| free(lib_name); |
| fclose(fp); |
| return result; |
| } |
| |
| void OS::SignalCodeMovingGC() { |
| // Support for ll_prof.py. |
| // |
| // The Linux profiler built into the kernel logs all mmap's with |
| // PROT_EXEC so that analysis tools can properly attribute ticks. We |
| // do a mmap with a name known by ll_prof.py and immediately munmap |
| // it. This injects a GC marker into the stream of events generated |
| // by the kernel and allows us to synchronize V8 code log and the |
| // kernel log. |
| long size = sysconf(_SC_PAGESIZE); // NOLINT(runtime/int) |
| FILE* f = fopen(OS::GetGCFakeMMapFile(), "w+"); |
| if (f == nullptr) { |
| OS::PrintError("Failed to open %s\n", OS::GetGCFakeMMapFile()); |
| OS::Abort(); |
| } |
| void* addr = mmap(OS::GetRandomMmapAddr(), size, PROT_READ | PROT_EXEC, |
| MAP_PRIVATE, fileno(f), 0); |
| DCHECK_NE(MAP_FAILED, addr); |
| CHECK(Free(addr, size)); |
| fclose(f); |
| } |
| |
| void OS::AdjustSchedulingParams() {} |
| |
| void* OS::RemapShared(void* old_address, void* new_address, size_t size) { |
| void* result = |
| mremap(old_address, 0, size, MREMAP_FIXED | MREMAP_MAYMOVE, new_address); |
| |
| if (result == MAP_FAILED) { |
| return nullptr; |
| } |
| DCHECK(result == new_address); |
| return result; |
| } |
| |
| } // namespace base |
| } // namespace v8 |