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lldb-netbsd: Read process virtual memory mapping
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Port GetMemoryRegionInfo to NetBSD.

Sponsored by <The NetBSD Foundation>
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@krytarowski
krytarowski committed Mar 15, 2017
1 parent 1d14729 commit d4af362
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Showing 3 changed files with 87 additions and 106 deletions.
4 changes: 2 additions & 2 deletions lldb-netbsd/distinfo
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Expand Up @@ -26,8 +26,8 @@ SHA1 (patch-source_Plugins_DynamicLoader_POSIX-DYLD_DYLDRendezvous.cpp) = 32d683
SHA1 (patch-source_Plugins_DynamicLoader_POSIX-DYLD_DynamicLoaderPOSIXDYLD.cpp) = ed8077e029281f6d1a9f043edc5a3b16d126eea2
SHA1 (patch-source_Plugins_Process_CMakeLists.txt) = c689ff4ec455234f8d506dc9eb8e0ed7f750d426
SHA1 (patch-source_Plugins_Process_NetBSD_CMakeLists.txt) = a77f397020ab752875813a7a93b53ccd3a130e6f
SHA1 (patch-source_Plugins_Process_NetBSD_NativeProcessNetBSD.cpp) = 5a14d0b981c33db9c8878c93f74bc67f5112a114
SHA1 (patch-source_Plugins_Process_NetBSD_NativeProcessNetBSD.h) = c48bb2dd45682164ab904b8b3f7664b91ac35d5b
SHA1 (patch-source_Plugins_Process_NetBSD_NativeProcessNetBSD.cpp) = 78521c12fbd070ba6221fd2619630bf8306e4cbf
SHA1 (patch-source_Plugins_Process_NetBSD_NativeProcessNetBSD.h) = f051f86d7ca2047e9f4d414e46f454e626348c14
SHA1 (patch-source_Plugins_Process_NetBSD_NativeRegisterContextNetBSD.cpp) = 89a9f56d1ee3103ac73c274f233f0d6816e20363
SHA1 (patch-source_Plugins_Process_NetBSD_NativeRegisterContextNetBSD.h) = dccd470b53937f58c5697f7e2507cc76db497ce8
SHA1 (patch-source_Plugins_Process_NetBSD_NativeRegisterContextNetBSD__x86__64.cpp) = cd0965e27e5b2374708b392ec707a5f98f2392d8
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181 changes: 80 additions & 101 deletions lldb-netbsd/patches/patch-source_Plugins_Process_NetBSD_NativeProcessNetBSD.cpp
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Expand Up @@ -2,7 +2,7 @@

--- source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp.orig 2017-03-14 16:45:14.522261905 +0000
+++ source/Plugins/Process/NetBSD/NativeProcessNetBSD.cpp
@@ -0,0 +1,1397 @@
@@ -0,0 +1,1376 @@
+//===-- NativeProcessNetBSD.cpp -------------------------------- -*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
Expand All @@ -15,10 +15,15 @@
+#include "NativeProcessNetBSD.h"
+
+// C Includes
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#include <uvm/uvm_prot.h>
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <util.h>
+
+// C++ Includes
+#include <fstream>
Expand Down Expand Up @@ -867,120 +872,31 @@
+ return error;
+}
+
+static Error
+ParseMemoryRegionInfoFromProcMapsLine(const std::string &maps_line,
+ MemoryRegionInfo &memory_region_info) {
+ memory_region_info.Clear();
+
+ StringExtractor line_extractor(maps_line.c_str());
+
+ // Format: {address_start_hex}-{address_end_hex} perms offset dev inode
+ // pathname
+ // perms: rwxp (letter is present if set, '-' if not, final character is
+ // p=private, s=shared).
+
+ // Parse out the starting address
+ lldb::addr_t start_address = line_extractor.GetHexMaxU64(false, 0);
+
+ // Parse out hyphen separating start and end address from range.
+ if (!line_extractor.GetBytesLeft() || (line_extractor.GetChar() != '-'))
+ return Error(
+ "malformed /proc/{pid}/maps entry, missing dash between address range");
+
+ // Parse out the ending address
+ lldb::addr_t end_address = line_extractor.GetHexMaxU64(false, start_address);
+
+ // Parse out the space after the address.
+ if (!line_extractor.GetBytesLeft() || (line_extractor.GetChar() != ' '))
+ return Error("malformed /proc/{pid}/maps entry, missing space after range");
+
+ // Save the range.
+ memory_region_info.GetRange().SetRangeBase(start_address);
+ memory_region_info.GetRange().SetRangeEnd(end_address);
+
+ // Any memory region in /proc/{pid}/maps is by definition mapped into the
+ // process.
+ memory_region_info.SetMapped(MemoryRegionInfo::OptionalBool::eYes);
+
+ // Parse out each permission entry.
+ if (line_extractor.GetBytesLeft() < 4)
+ return Error("malformed /proc/{pid}/maps entry, missing some portion of "
+ "permissions");
+
+ // Handle read permission.
+ const char read_perm_char = line_extractor.GetChar();
+ if (read_perm_char == 'r')
+ memory_region_info.SetReadable(MemoryRegionInfo::OptionalBool::eYes);
+ else if (read_perm_char == '-')
+ memory_region_info.SetReadable(MemoryRegionInfo::OptionalBool::eNo);
+ else
+ return Error("unexpected /proc/{pid}/maps read permission char");
+
+ // Handle write permission.
+ const char write_perm_char = line_extractor.GetChar();
+ if (write_perm_char == 'w')
+ memory_region_info.SetWritable(MemoryRegionInfo::OptionalBool::eYes);
+ else if (write_perm_char == '-')
+ memory_region_info.SetWritable(MemoryRegionInfo::OptionalBool::eNo);
+ else
+ return Error("unexpected /proc/{pid}/maps write permission char");
+
+ // Handle execute permission.
+ const char exec_perm_char = line_extractor.GetChar();
+ if (exec_perm_char == 'x')
+ memory_region_info.SetExecutable(MemoryRegionInfo::OptionalBool::eYes);
+ else if (exec_perm_char == '-')
+ memory_region_info.SetExecutable(MemoryRegionInfo::OptionalBool::eNo);
+ else
+ return Error("unexpected /proc/{pid}/maps exec permission char");
+
+ line_extractor.GetChar(); // Read the private bit
+ line_extractor.SkipSpaces(); // Skip the separator
+ line_extractor.GetHexMaxU64(false, 0); // Read the offset
+ line_extractor.GetHexMaxU64(false, 0); // Read the major device number
+ line_extractor.GetChar(); // Read the device id separator
+ line_extractor.GetHexMaxU64(false, 0); // Read the major device number
+ line_extractor.SkipSpaces(); // Skip the separator
+ line_extractor.GetU64(0, 10); // Read the inode number
+
+ line_extractor.SkipSpaces();
+ const char *name = line_extractor.Peek();
+ if (name)
+ memory_region_info.SetName(name);
+
+ return Error();
+}
+
+Error NativeProcessNetBSD::GetMemoryRegionInfo(lldb::addr_t load_addr,
+ MemoryRegionInfo &range_info) {
+#if 0
+ // FIXME review that the final memory region returned extends to the end of
+ // the virtual address space,
+ // with no perms if it is not mapped.
+
+ // Use an approach that reads memory regions from /proc/{pid}/maps.
+ // Assume proc maps entries are in ascending order.
+ // FIXME assert if we find differently.
+
+ if (m_supports_mem_region == LazyBool::eLazyBoolNo) {
+ // We're done.
+ return Error("unsupported");
+ }
+
+ lldb::addr_t prev_base_address = 0;
+ Error error = PopulateMemoryRegionCache();
+ if (error.Fail()) {
+ return error;
+ }
+
+ lldb::addr_t prev_base_address = 0;
+ // FIXME start by finding the last region that is <= target address using
+ // binary search. Data is sorted.
+ // There can be a ton of regions on pthreads apps with lots of threads.
+ for (auto it = m_mem_region_cache.begin(); it != m_mem_region_cache.end();
+ ++it) {
+ MemoryRegionInfo &proc_entry_info = *it;
+
+ MemoryRegionInfo &proc_entry_info = it->first;
+ // Sanity check assumption that /proc/{pid}/maps entries are ascending.
+ assert((proc_entry_info.GetRange().GetRangeBase() >= prev_base_address) &&
+ "descending /proc/pid/maps entries detected, unexpected");
+ prev_base_address = proc_entry_info.GetRange().GetRangeBase();
+
+ UNUSED_IF_ASSERT_DISABLED(prev_base_address);
+ // If the target address comes before this entry, indicate distance to next
+ // region.
+ if (load_addr < proc_entry_info.GetRange().GetRangeBase()) {
Expand All @@ -991,18 +907,15 @@
+ range_info.SetWritable(MemoryRegionInfo::OptionalBool::eNo);
+ range_info.SetExecutable(MemoryRegionInfo::OptionalBool::eNo);
+ range_info.SetMapped(MemoryRegionInfo::OptionalBool::eNo);
+
+ return error;
+ } else if (proc_entry_info.GetRange().Contains(load_addr)) {
+ // The target address is within the memory region we're processing here.
+ range_info = proc_entry_info;
+ return error;
+ }
+
+ // The target memory address comes somewhere after the region we just
+ // parsed.
+ }
+
+ // If we made it here, we didn't find an entry that contained the given
+ // address. Return the
+ // load_addr as start and the amount of bytes betwwen load address and the end
Expand All @@ -1015,7 +928,73 @@
+ range_info.SetExecutable(MemoryRegionInfo::OptionalBool::eNo);
+ range_info.SetMapped(MemoryRegionInfo::OptionalBool::eNo);
+ return error;
+#endif
+}
+
+
+Error NativeProcessNetBSD::PopulateMemoryRegionCache() {
+ Log *log(ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_PROCESS));
+ // If our cache is empty, pull the latest. There should always be at least
+ // one memory region if memory region handling is supported.
+ if (!m_mem_region_cache.empty()) {
+ LLDB_LOG(log, "reusing {0} cached memory region entries",
+ m_mem_region_cache.size());
+ return Error();
+ }
+
+ struct kinfo_vmentry *vm;
+ size_t count, i;
+ vm = kinfo_getvmmap(getpid(), &count);
+ if (vm == NULL) {
+ m_supports_mem_region = LazyBool::eLazyBoolNo;
+ Error error;
+ error.SetErrorString("not supported");
+ return error;
+ }
+ for (i = 0; i < count; i++) {
+ MemoryRegionInfo info;
+ info.Clear();
+ info.GetRange().SetRangeBase(vm[i].kve_start);
+ info.GetRange().SetRangeEnd(vm[i].kve_end);
+ info.SetMapped(MemoryRegionInfo::OptionalBool::eYes);
+
+ if (vm[i].kve_protection & VM_PROT_READ)
+ info.SetReadable(MemoryRegionInfo::OptionalBool::eYes);
+ else
+ info.SetReadable(MemoryRegionInfo::OptionalBool::eNo);
+
+ if (vm[i].kve_protection & VM_PROT_WRITE)
+ info.SetWritable(MemoryRegionInfo::OptionalBool::eYes);
+ else
+ info.SetWritable(MemoryRegionInfo::OptionalBool::eNo);
+
+ if (vm[i].kve_protection & VM_PROT_EXECUTE)
+ info.SetExecutable(MemoryRegionInfo::OptionalBool::eYes);
+ else
+ info.SetExecutable(MemoryRegionInfo::OptionalBool::eNo);
+
+ if (vm[i].kve_path)
+ info.SetName(vm[i].kve_path);
+
+ m_mem_region_cache.emplace_back(
+ info, FileSpec(info.GetName().GetCString(), true));
+ }
+ free(vm);
+
+ if (m_mem_region_cache.empty()) {
+ // No entries after attempting to read them. This shouldn't happen.
+ // Assume we don't support map entries.
+ LLDB_LOG(log,
+ "failed to find any vmmap entries, assuming no support "
+ "for memory region metadata retrieval");
+ m_supports_mem_region = LazyBool::eLazyBoolNo;
+ Error error;
+ error.SetErrorString("not supported");
+ return error;
+ }
+ LLDB_LOG(log, "read {0} memory region entries from process {1}",
+ m_mem_region_cache.size(), GetID());
+ // We support memory retrieval, remember that.
+ m_supports_mem_region = LazyBool::eLazyBoolYes;
+ return Error();
+}
+
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8 changes: 5 additions & 3 deletions lldb-netbsd/patches/patch-source_Plugins_Process_NetBSD_NativeProcessNetBSD.h
View file
@@ -1,8 +1,8 @@
$NetBSD$

--- source/Plugins/Process/NetBSD/NativeProcessNetBSD.h.orig 2017-01-31 18:01:27.506688091 +0000
--- source/Plugins/Process/NetBSD/NativeProcessNetBSD.h.orig 2017-03-14 16:45:14.529112718 +0000
+++ source/Plugins/Process/NetBSD/NativeProcessNetBSD.h
@@ -0,0 +1,183 @@
@@ -0,0 +1,185 @@
+//===-- NativeProcessNetBSD.h ---------------------------------- -*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
Expand Down Expand Up @@ -122,7 +122,7 @@
+ ArchSpec m_arch;
+
+ LazyBool m_supports_mem_region;
+ std::vector<MemoryRegionInfo> m_mem_region_cache;
+ std::vector<std::pair<MemoryRegionInfo, FileSpec>> m_mem_region_cache;
+
+ lldb::tid_t m_pending_notification_tid;
+
Expand Down Expand Up @@ -180,6 +180,8 @@
+ int signo);
+
+ void SigchldHandler();
+
+ Error PopulateMemoryRegionCache();
+};
+
+} // namespace process_netbsd
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