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//===-- LinuxProcMaps.cpp -------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "LinuxProcMaps.h"
#include "lldb/Target/MemoryRegionInfo.h"
#include "lldb/Utility/Status.h"
#include "lldb/Utility/StringExtractor.h"
#include "llvm/ADT/StringRef.h"
#include <optional>
using namespace lldb_private;
enum class MapsKind { Maps, SMaps };
static llvm::Expected<MemoryRegionInfo> ProcMapError(const char *msg,
MapsKind kind) {
return llvm::createStringError(llvm::inconvertibleErrorCode(), msg,
kind == MapsKind::Maps ? "maps" : "smaps");
}
static llvm::Expected<MemoryRegionInfo>
ParseMemoryRegionInfoFromProcMapsLine(llvm::StringRef maps_line,
MapsKind maps_kind) {
MemoryRegionInfo region;
StringExtractor line_extractor(maps_line);
// 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 ProcMapError(
"malformed /proc/{pid}/%s entry, missing dash between address range",
maps_kind);
// 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 ProcMapError(
"malformed /proc/{pid}/%s entry, missing space after range", maps_kind);
// Save the range.
region.GetRange().SetRangeBase(start_address);
region.GetRange().SetRangeEnd(end_address);
// Any memory region in /proc/{pid}/(maps|smaps) is by definition mapped
// into the process.
region.SetMapped(MemoryRegionInfo::OptionalBool::eYes);
// Parse out each permission entry.
if (line_extractor.GetBytesLeft() < 4)
return ProcMapError(
"malformed /proc/{pid}/%s entry, missing some portion of "
"permissions",
maps_kind);
// Handle read permission.
const char read_perm_char = line_extractor.GetChar();
if (read_perm_char == 'r')
region.SetReadable(MemoryRegionInfo::OptionalBool::eYes);
else if (read_perm_char == '-')
region.SetReadable(MemoryRegionInfo::OptionalBool::eNo);
else
return ProcMapError("unexpected /proc/{pid}/%s read permission char",
maps_kind);
// Handle write permission.
const char write_perm_char = line_extractor.GetChar();
if (write_perm_char == 'w')
region.SetWritable(MemoryRegionInfo::OptionalBool::eYes);
else if (write_perm_char == '-')
region.SetWritable(MemoryRegionInfo::OptionalBool::eNo);
else
return ProcMapError("unexpected /proc/{pid}/%s write permission char",
maps_kind);
// Handle execute permission.
const char exec_perm_char = line_extractor.GetChar();
if (exec_perm_char == 'x')
region.SetExecutable(MemoryRegionInfo::OptionalBool::eYes);
else if (exec_perm_char == '-')
region.SetExecutable(MemoryRegionInfo::OptionalBool::eNo);
else
return ProcMapError("unexpected /proc/{pid}/%s exec permission char",
maps_kind);
// Handle sharing status (private/shared).
const char sharing_char = line_extractor.GetChar();
if (sharing_char == 's')
region.SetShared(MemoryRegionInfo::OptionalBool::eYes);
else if (sharing_char == 'p')
region.SetShared(MemoryRegionInfo::OptionalBool::eNo);
else
region.SetShared(MemoryRegionInfo::OptionalBool::eDontKnow);
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)
region.SetName(name);
return region;
}
void lldb_private::ParseLinuxMapRegions(llvm::StringRef linux_map,
LinuxMapCallback const &callback) {
llvm::StringRef lines(linux_map);
llvm::StringRef line;
while (!lines.empty()) {
std::tie(line, lines) = lines.split('\n');
if (!callback(ParseMemoryRegionInfoFromProcMapsLine(line, MapsKind::Maps)))
break;
}
}
void lldb_private::ParseLinuxSMapRegions(llvm::StringRef linux_smap,
LinuxMapCallback const &callback) {
// Entries in /smaps look like:
// 00400000-0048a000 r-xp 00000000 fd:03 960637
// Size: 552 kB
// Rss: 460 kB
// <...>
// VmFlags: rd ex mr mw me dw
// 00500000-0058a000 rwxp 00000000 fd:03 960637
// <...>
//
// Where the first line is identical to the /maps format
// and VmFlags is only printed for kernels >= 3.8.
llvm::StringRef lines(linux_smap);
llvm::StringRef line;
std::optional<MemoryRegionInfo> region;
while (lines.size()) {
std::tie(line, lines) = lines.split('\n');
// A property line looks like:
// <word>: <value>
// (no spaces on the left hand side)
// A header will have a ':' but the LHS will contain spaces
llvm::StringRef name;
llvm::StringRef value;
std::tie(name, value) = line.split(':');
// If this line is a property line
if (!name.contains(' ')) {
if (region) {
if (name == "VmFlags") {
region->SetMemoryTagged(MemoryRegionInfo::eNo);
region->SetIsShadowStack(MemoryRegionInfo::eNo);
llvm::SmallVector<llvm::StringRef> flags;
value.split(flags, ' ', /*MaxSplit=*/-1, /*KeepEmpty=*/false);
for (llvm::StringRef flag : flags)
if (flag == "mt")
region->SetMemoryTagged(MemoryRegionInfo::eYes);
else if (flag == "ss")
region->SetIsShadowStack(MemoryRegionInfo::eYes);
}
} else {
// Orphaned settings line
callback(ProcMapError(
"Found a property line without a corresponding mapping "
"in /proc/{pid}/%s",
MapsKind::SMaps));
return;
}
} else {
// Must be a new region header
if (region) {
// Save current region
callback(*region);
region.reset();
}
// Try to start a new region
llvm::Expected<MemoryRegionInfo> new_region =
ParseMemoryRegionInfoFromProcMapsLine(line, MapsKind::SMaps);
if (new_region) {
region = *new_region;
} else {
// Stop at first invalid region header
callback(new_region.takeError());
return;
}
}
}
// Catch last region
if (region)
callback(*region);
}
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