fix condition in LookUpMapping, and some cosmetic fixes

This commit is contained in:
Benoit Jacob 2020-11-23 11:56:08 -05:00
parent d787636804
commit fc8ef12a78

View File

@ -2898,7 +2898,6 @@ void Profiler::HandleParameter( uint64_t payload )
}
#ifdef __ANDROID__
namespace {
// Implementation helpers of EnsureReadable(address).
// This is so far only needed on Android, where it is common for libraries to be mapped
// with only executable, not readable, permissions. Typical example (line from /proc/self/maps):
@ -2909,6 +2908,7 @@ namespace {
// To work around this, we parse /proc/self/maps and we use mprotect to set read permissions
// on any mappings that contain symbols addresses hit by HandleSymbolCodeQuery.
namespace {
// Holds some information about a single memory mapping.
struct MappingInfo {
// Start of address range. Inclusive.
@ -2919,13 +2919,14 @@ struct MappingInfo {
// Read/Write/Executable permissions.
bool perm_r, perm_w, perm_x;
};
} // anonymous namespace
// Internal implementation helper for LookUpMapping(address).
//
// Parses /proc/self/maps returning a vector<MappingInfo>.
// /proc/self/maps is assumed to be sorted by ascending address, so the resulting
// vector is sorted by ascending address too.
std::vector<MappingInfo> ParseMappings()
static std::vector<MappingInfo> ParseMappings()
{
std::vector<MappingInfo> result;
FILE* file = fopen( "/proc/self/maps", "r" );
@ -2959,7 +2960,7 @@ std::vector<MappingInfo> ParseMappings()
// sorted by increasing addresses, as /proc/self/maps seems to be.
// Returns a pointer to the MappingInfo describing the mapping that this
// address belongs to, or nullptr if the address isn't in `mappings`.
MappingInfo* LookUpMapping(std::vector<MappingInfo>& mappings, uintptr_t address)
static MappingInfo* LookUpMapping(std::vector<MappingInfo>& mappings, uintptr_t address)
{
// Comparison function for std::lower_bound. Returns true if all addresses in `m1`
// are lower than `addr`.
@ -2968,7 +2969,7 @@ MappingInfo* LookUpMapping(std::vector<MappingInfo>& mappings, uintptr_t address
return m1.end_address <= addr;
};
auto iter = std::lower_bound( mappings.begin(), mappings.end(), address, Compare );
if( iter == mappings.end() || iter->end_address <= address) {
if( iter == mappings.end() || iter->start_address > address) {
return nullptr;
}
return &*iter;
@ -2984,7 +2985,7 @@ MappingInfo* LookUpMapping(std::vector<MappingInfo>& mappings, uintptr_t address
// only one thread). It holds a vector of mappings parsed from /proc/self/maps.
//
// Attempts to react to mappings changes by re-parsing /proc/self/maps.
MappingInfo* LookUpMapping(uintptr_t address)
static MappingInfo* LookUpMapping(uintptr_t address)
{
// Static state managed by this function. Not constant, we mutate that state as
// we turn some mappings readable. Initially parsed once here, updated as needed below.
@ -3002,7 +3003,7 @@ MappingInfo* LookUpMapping(uintptr_t address)
//
// Attempts to make the specified `mapping` readable if it isn't already.
// Returns true if and only if the mapping is readable.
bool EnsureReadable( MappingInfo& mapping )
static bool EnsureReadable( MappingInfo& mapping )
{
if( mapping.perm_r )
{
@ -3027,14 +3028,13 @@ bool EnsureReadable( MappingInfo& mapping )
}
// Attempts to set the read permission on the entire mapping containing the
// specified address.
bool EnsureReadable( uintptr_t address )
// specified address. Returns true if and only if the mapping is now readable.
static bool EnsureReadable( uintptr_t address )
{
MappingInfo* mapping = LookUpMapping(address);
return mapping && EnsureReadable( *mapping );
}
} // anonymous namespace
#endif // defined __ANDROID__
void Profiler::HandleSymbolQuery( uint64_t symbol )