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Kernel: Tidy up Coredump construction

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- Use KResultOr and TRY to propagate errors
- Return more specific errors now that they have a path out from here
This commit is contained in:
Andreas Kling 2021-09-06 17:33:37 +02:00
parent c11c0fe453
commit 60eea6940f
3 changed files with 26 additions and 39 deletions
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51
Kernel/Coredump.cpp
View file

@ -23,52 +23,39 @@
namespace Kernel { namespace Kernel {
OwnPtr<Coredump> Coredump::create(NonnullRefPtr<Process> process, const String& output_path) KResultOr<NonnullOwnPtr<Coredump>> Coredump::try_create(NonnullRefPtr<Process> process, StringView output_path)
{ {
if (!process->is_dumpable()) { if (!process->is_dumpable()) {
dbgln("Refusing to generate coredump for non-dumpable process {}", process->pid().value()); dbgln("Refusing to generate coredump for non-dumpable process {}", process->pid().value());
return {}; return EPERM;
} }
auto fd = create_target_file(process, output_path); auto description = TRY(try_create_target_file(process, output_path));
if (!fd) return adopt_nonnull_own_or_enomem(new (nothrow) Coredump(move(process), move(description)));
return {};
return adopt_own_if_nonnull(new (nothrow) Coredump(move(process), fd.release_nonnull()));
} }
Coredump::Coredump(NonnullRefPtr<Process> process, NonnullRefPtr<FileDescription>&& fd) Coredump::Coredump(NonnullRefPtr<Process> process, NonnullRefPtr<FileDescription> description)
: m_process(move(process)) : m_process(move(process))
, m_fd(move(fd)) , m_description(move(description))
, m_num_program_headers(m_process->address_space().region_count() + 1) // +1 for NOTE segment , m_num_program_headers(m_process->address_space().region_count() + 1) // +1 for NOTE segment
{ {
} }
RefPtr<FileDescription> Coredump::create_target_file(const Process& process, const String& output_path) KResultOr<NonnullRefPtr<FileDescription>> Coredump::try_create_target_file(Process const& process, StringView output_path)
{ {
auto output_directory = KLexicalPath::dirname(output_path); auto output_directory = KLexicalPath::dirname(output_path);
auto dump_directory = VirtualFileSystem::the().open_directory(output_directory, VirtualFileSystem::the().root_custody()); auto dump_directory = TRY(VirtualFileSystem::the().open_directory(output_directory, VirtualFileSystem::the().root_custody()));
if (dump_directory.is_error()) { auto dump_directory_metadata = dump_directory->inode().metadata();
dbgln("Can't find directory '{}' for coredump", output_directory);
return nullptr;
}
auto dump_directory_metadata = dump_directory.value()->inode().metadata();
if (dump_directory_metadata.uid != 0 || dump_directory_metadata.gid != 0 || dump_directory_metadata.mode != 040777) { if (dump_directory_metadata.uid != 0 || dump_directory_metadata.gid != 0 || dump_directory_metadata.mode != 040777) {
dbgln("Refusing to put coredump in sketchy directory '{}'", output_directory); dbgln("Refusing to put coredump in sketchy directory '{}'", output_directory);
return nullptr; return EINVAL;
} }
auto fd_or_error = VirtualFileSystem::the().open( return TRY(VirtualFileSystem::the().open(
KLexicalPath::basename(output_path), KLexicalPath::basename(output_path),
O_CREAT | O_WRONLY | O_EXCL, O_CREAT | O_WRONLY | O_EXCL,
S_IFREG, // We will enable reading from userspace when we finish generating the coredump file S_IFREG, // We will enable reading from userspace when we finish generating the coredump file
*dump_directory.value(), *dump_directory,
UidAndGid { process.uid(), process.gid() }); UidAndGid { process.uid(), process.gid() }));
if (fd_or_error.is_error()) {
dbgln("Failed to open coredump '{}' for writing", output_path);
return nullptr;
}
return fd_or_error.value();
} }
KResult Coredump::write_elf_header() KResult Coredump::write_elf_header()
@ -111,7 +98,7 @@ KResult Coredump::write_elf_header()
elf_file_header.e_shnum = 0; elf_file_header.e_shnum = 0;
elf_file_header.e_shstrndx = SHN_UNDEF; elf_file_header.e_shstrndx = SHN_UNDEF;
TRY(m_fd->write(UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<uint8_t*>(&elf_file_header)), sizeof(ElfW(Ehdr)))); TRY(m_description->write(UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<uint8_t*>(&elf_file_header)), sizeof(ElfW(Ehdr))));
return KSuccess; return KSuccess;
} }
@ -139,7 +126,7 @@ KResult Coredump::write_program_headers(size_t notes_size)
offset += phdr.p_filesz; offset += phdr.p_filesz;
[[maybe_unused]] auto rc = m_fd->write(UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<uint8_t*>(&phdr)), sizeof(ElfW(Phdr))); [[maybe_unused]] auto rc = m_description->write(UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<uint8_t*>(&phdr)), sizeof(ElfW(Phdr)));
} }
ElfW(Phdr) notes_pheader {}; ElfW(Phdr) notes_pheader {};
@ -152,7 +139,7 @@ KResult Coredump::write_program_headers(size_t notes_size)
notes_pheader.p_align = 0; notes_pheader.p_align = 0;
notes_pheader.p_flags = 0; notes_pheader.p_flags = 0;
TRY(m_fd->write(UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<uint8_t*>(&notes_pheader)), sizeof(ElfW(Phdr)))); TRY(m_description->write(UserOrKernelBuffer::for_kernel_buffer(reinterpret_cast<uint8_t*>(&notes_pheader)), sizeof(ElfW(Phdr))));
return KSuccess; return KSuccess;
} }
@ -180,7 +167,7 @@ KResult Coredump::write_regions()
// (A page may not be backed by a physical page because it has never been faulted in when the process ran). // (A page may not be backed by a physical page because it has never been faulted in when the process ran).
src_buffer = UserOrKernelBuffer::for_kernel_buffer(zero_buffer); src_buffer = UserOrKernelBuffer::for_kernel_buffer(zero_buffer);
} }
TRY(m_fd->write(src_buffer.value(), PAGE_SIZE)); TRY(m_description->write(src_buffer.value(), PAGE_SIZE));
} }
} }
return KSuccess; return KSuccess;
@ -188,7 +175,7 @@ KResult Coredump::write_regions()
KResult Coredump::write_notes_segment(ByteBuffer& notes_segment) KResult Coredump::write_notes_segment(ByteBuffer& notes_segment)
{ {
TRY(m_fd->write(UserOrKernelBuffer::for_kernel_buffer(notes_segment.data()), notes_segment.size())); TRY(m_description->write(UserOrKernelBuffer::for_kernel_buffer(notes_segment.data()), notes_segment.size()));
return KSuccess; return KSuccess;
} }
@ -345,7 +332,7 @@ KResult Coredump::write()
TRY(write_regions()); TRY(write_regions());
TRY(write_notes_segment(notes_segment)); TRY(write_notes_segment(notes_segment));
return m_fd->chmod(0600); // Make coredump file read/writable return m_description->chmod(0600); // Make coredump file read/writable
} }
} }

8
Kernel/Coredump.h
View file

@ -15,14 +15,14 @@ namespace Kernel {
class Coredump { class Coredump {
public: public:
static OwnPtr<Coredump> create(NonnullRefPtr<Process>, const String& output_path); static KResultOr<NonnullOwnPtr<Coredump>> try_create(NonnullRefPtr<Process>, StringView output_path);
~Coredump() = default; ~Coredump() = default;
[[nodiscard]] KResult write(); [[nodiscard]] KResult write();
private: private:
Coredump(NonnullRefPtr<Process>, NonnullRefPtr<FileDescription>&&); Coredump(NonnullRefPtr<Process>, NonnullRefPtr<FileDescription>);
static RefPtr<FileDescription> create_target_file(const Process&, const String& output_path); static KResultOr<NonnullRefPtr<FileDescription>> try_create_target_file(Process const&, StringView output_path);
[[nodiscard]] KResult write_elf_header(); [[nodiscard]] KResult write_elf_header();
[[nodiscard]] KResult write_program_headers(size_t notes_size); [[nodiscard]] KResult write_program_headers(size_t notes_size);
@ -36,7 +36,7 @@ private:
KResultOr<ByteBuffer> create_notes_metadata_data() const; KResultOr<ByteBuffer> create_notes_metadata_data() const;
NonnullRefPtr<Process> m_process; NonnullRefPtr<Process> m_process;
NonnullRefPtr<FileDescription> m_fd; NonnullRefPtr<FileDescription> m_description;
const size_t m_num_program_headers; const size_t m_num_program_headers;
}; };

6
Kernel/Process.cpp
View file

@ -553,10 +553,10 @@ bool Process::dump_core()
VERIFY(should_generate_coredump()); VERIFY(should_generate_coredump());
dbgln("Generating coredump for pid: {}", pid().value()); dbgln("Generating coredump for pid: {}", pid().value());
auto coredump_path = String::formatted("/tmp/coredump/{}_{}_{}", name(), pid().value(), kgettimeofday().to_truncated_seconds()); auto coredump_path = String::formatted("/tmp/coredump/{}_{}_{}", name(), pid().value(), kgettimeofday().to_truncated_seconds());
auto coredump = Coredump::create(*this, coredump_path); auto coredump_or_error = Coredump::try_create(*this, coredump_path);
if (!coredump) if (coredump_or_error.is_error())
return false; return false;
return !coredump->write().is_error(); return !coredump_or_error.value()->write().is_error();
} }
bool Process::dump_perfcore() bool Process::dump_perfcore()