diff options
| -rw-r--r-- | test/syscalls/linux/proc_net_unix.cc | 54 |
1 files changed, 36 insertions, 18 deletions
diff --git a/test/syscalls/linux/proc_net_unix.cc b/test/syscalls/linux/proc_net_unix.cc index 9b9be66ff..83dbd1364 100644 --- a/test/syscalls/linux/proc_net_unix.cc +++ b/test/syscalls/linux/proc_net_unix.cc @@ -56,19 +56,44 @@ struct UnixEntry { std::string path; }; +// Abstract socket paths can have either trailing null bytes or '@'s as padding +// at the end, depending on the linux version. This function strips any such +// padding. +void StripAbstractPathPadding(std::string* s) { + const char pad_char = s->back(); + if (pad_char != '\0' && pad_char != '@') { + return; + } + + const auto last_pos = s->find_last_not_of(pad_char); + if (last_pos != std::string::npos) { + s->resize(last_pos + 1); + } +} + +// Precondition: addr must be a unix socket address (i.e. sockaddr_un) and +// addr->sun_path must be null-terminated. This is always the case if addr comes +// from Linux: +// +// Per man unix(7): +// +// "When the address of a pathname socket is returned (by [getsockname(2)]), its +// length is +// +// offsetof(struct sockaddr_un, sun_path) + strlen(sun_path) + 1 +// +// and sun_path contains the null-terminated pathname." std::string ExtractPath(const struct sockaddr* addr) { const char* path = reinterpret_cast<const struct sockaddr_un*>(addr)->sun_path; // Note: sockaddr_un.sun_path is an embedded character array of length // UNIX_PATH_MAX, so we can always safely dereference the first 2 bytes below. // - // The kernel also enforces that the path is always null terminated. + // We also rely on the path being null-terminated. if (path[0] == 0) { - // Abstract socket paths are null padded to the end of the struct - // sockaddr. However, these null bytes may or may not show up in - // /proc/net/unix depending on the kernel version. Truncate after the first - // null byte (by treating path as a c-string). - return StrCat("@", &path[1]); + std::string abstract_path = StrCat("@", &path[1]); + StripAbstractPathPadding(&abstract_path); + return abstract_path; } return std::string(path); } @@ -96,14 +121,6 @@ PosixErrorOr<std::vector<UnixEntry>> ProcNetUnixEntries() { continue; } - // Abstract socket paths can have trailing null bytes in them depending on - // the linux version. Strip off everything after a null byte, including the - // null byte. - std::size_t null_pos = line.find('\0'); - if (null_pos != std::string::npos) { - line.erase(null_pos); - } - // Parse a single entry from /proc/net/unix. // // Sample file: @@ -151,6 +168,7 @@ PosixErrorOr<std::vector<UnixEntry>> ProcNetUnixEntries() { entry.path = ""; if (fields.size() > 1) { entry.path = fields[1]; + StripAbstractPathPadding(&entry.path); } entries.push_back(entry); @@ -200,8 +218,8 @@ TEST(ProcNetUnix, FilesystemBindAcceptConnect) { std::string path1 = ExtractPath(sockets->first_addr()); std::string path2 = ExtractPath(sockets->second_addr()); - std::cout << StreamFormat("Server socket address: %s\n", path1); - std::cout << StreamFormat("Client socket address: %s\n", path2); + std::cerr << StreamFormat("Server socket address (path1): %s\n", path1); + std::cerr << StreamFormat("Client socket address (path2): %s\n", path2); std::vector<UnixEntry> entries = ASSERT_NO_ERRNO_AND_VALUE(ProcNetUnixEntries()); @@ -224,8 +242,8 @@ TEST(ProcNetUnix, AbstractBindAcceptConnect) { std::string path1 = ExtractPath(sockets->first_addr()); std::string path2 = ExtractPath(sockets->second_addr()); - std::cout << StreamFormat("Server socket address: '%s'\n", path1); - std::cout << StreamFormat("Client socket address: '%s'\n", path2); + std::cerr << StreamFormat("Server socket address (path1): '%s'\n", path1); + std::cerr << StreamFormat("Client socket address (path2): '%s'\n", path2); std::vector<UnixEntry> entries = ASSERT_NO_ERRNO_AND_VALUE(ProcNetUnixEntries()); |