[ELF] Remove --preload

rui314 · Apr 30, 2022 · a85b1f5 · a85b1f5
1 parent d3130f3
commit a85b1f5
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Showing 4 changed files with 12 additions and 233 deletions.
diff --git a/elf/cmdline.cc b/elf/cmdline.cc
@@ -100,8 +100,6 @@ static const char helpmsg[] = R"(
   --pie, --pic-executable     Create a position independent executable
     --no-pie, --no-pic-executable
   --pop-state                 Pop state of flags governing input file handling
-  --preload
-    --no-preload
   --print-gc-sections         Print removed unreferenced sections
     --no-print-gc-sections
   --print-icf-sections        Print folded identical sections
@@ -948,12 +946,6 @@ void parse_nonpositional_args(Context<E> &ctx,
     } else if (read_arg(ctx, args, arg, "filter") ||
                read_arg(ctx, args, arg, "F")) {
       ctx.arg.filter.push_back(arg);
-    } else if (read_flag(args, "preload")) {
-      Warn(ctx) << "--preload is deprecated and will be removed in a"
-                << " future version";
-      ctx.arg.preload = true;
-    } else if (read_flag(args, "no-preload")) {
-      ctx.arg.preload = false;
     } else if (read_flag(args, "apply-dynamic-relocs")) {
     } else if (read_arg(ctx, args, arg, "O")) {
     } else if (read_flag(args, "O0")) {

diff --git a/elf/main.cc b/elf/main.cc
@@ -374,6 +374,7 @@ static int elf_main(int argc, char **argv) {
 
   // Parse non-positional command line options
   ctx.cmdline_args = expand_response_files(ctx, argv);
+
   std::vector<std::string_view> file_args;
   parse_nonpositional_args(ctx, file_args);
 
@@ -400,27 +401,29 @@ static int elf_main(int argc, char **argv) {
 
   Timer t_all(ctx, "all");
 
+  install_signal_handler();
+
+  if (!ctx.arg.directory.empty())
+    if (chdir(ctx.arg.directory.c_str()) == -1)
+      Fatal(ctx) << "chdir failed: " << ctx.arg.directory
+                 << ": " << errno_string();
+
   if (ctx.arg.relocatable) {
     combine_objects(ctx, file_args);
     return 0;
   }
 
-  if (!ctx.arg.preload)
-    try_resume_daemon(ctx);
+  // Fork a subprocess unless --no-fork is given.
+  std::function<void()> on_complete;
+  if (ctx.arg.fork)
+    on_complete = fork_child();
 
   i64 thread_count = ctx.arg.thread_count;
   if (thread_count == 0)
     thread_count = get_default_thread_count();
   tbb::global_control tbb_cont(tbb::global_control::max_allowed_parallelism,
                                thread_count);
 
-  install_signal_handler();
-
-  if (!ctx.arg.directory.empty())
-    if (chdir(ctx.arg.directory.c_str()) == -1)
-      Fatal(ctx) << "chdir failed: " << ctx.arg.directory
-                 << ": " << errno_string();
-
   // Handle --wrap options if any.
   for (std::string_view name : ctx.arg.wrap)
     get_symbol(ctx, name)->wrap = true;
@@ -430,31 +433,12 @@ static int elf_main(int argc, char **argv) {
     for (std::string_view name : *ctx.arg.retain_symbols_file)
       get_symbol(ctx, name)->write_to_symtab = true;
 
-  // Preload input files
-  std::function<void()> on_complete;
-  std::function<void()> wait_for_client;
-
-  if (ctx.arg.preload)
-    daemonize(ctx, &wait_for_client, &on_complete);
-  else if (ctx.arg.fork)
-    on_complete = fork_child();
-
   for (std::string_view arg : ctx.arg.trace_symbol)
     get_symbol(ctx, arg)->traced = true;
 
   // Parse input files
   read_input_files(ctx, file_args);
 
-  if (ctx.arg.preload) {
-    wait_for_client();
-    if (!reload_input_files(ctx)) {
-      std::vector<char *> args(argv, argv + argc);
-      args.push_back((char *)"--no-preload");
-      args.push_back(nullptr);
-      return elf_main<E>(argc + 1, args.data());
-    }
-  }
-
   // Uniquify shared object files by soname
   {
     std::unordered_set<std::string_view> seen;

diff --git a/elf/mold.h b/elf/mold.h
@@ -1340,13 +1340,6 @@ void print_map(Context<E> &ctx);
 
 std::function<void()> fork_child();
 
-template <typename E>
-void try_resume_daemon(Context<E> &ctx);
-
-template <typename E>
-void daemonize(Context<E> &ctx, std::function<void()> *wait_for_client,
-               std::function<void()> *on_complete);
-
 template <typename E>
 [[noreturn]]
 void process_run_subcommand(Context<E> &ctx, int argc, char **argv);
@@ -1603,7 +1596,6 @@ struct Context {
     bool perf = false;
     bool pic = false;
     bool pie = false;
-    bool preload = false;
     bool print_gc_sections = false;
     bool print_icf_sections = false;
     bool print_map = false;

diff --git a/elf/subprocess.cc b/elf/subprocess.cc
@@ -60,192 +60,6 @@ std::function<void()> fork_child() {
   };
 }
 
-static std::string base64(u8 *data, u64 size) {
-  static const char chars[] =
-    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+_";
-
-  std::ostringstream out;
-
-  auto encode = [&](u32 x) {
-    out << chars[x & 0b111111]
-        << chars[(x >> 6) & 0b111111]
-        << chars[(x >> 12) & 0b111111]
-        << chars[(x >> 18) & 0b111111];
-  };
-
-  i64 i = 0;
-  for (; i < size - 3; i += 3)
-    encode((data[i + 2] << 16) | (data[i + 1] << 8) | data[i]);
-
-  if (i == size - 1)
-    encode(data[i]);
-  else if (i == size - 2)
-    encode((data[i + 1] << 8) | data[i]);
-  return out.str();
-}
-
-static std::string compute_sha256(std::span<std::string_view> argv) {
-  SHA256_CTX sha;
-  SHA256_Init(&sha);
-
-  for (std::string_view arg : argv) {
-    if (arg != "-preload" && arg != "--preload") {
-      SHA256_Update(&sha, arg.data(), arg.size());
-      char buf[] = {0};
-      SHA256_Update(&sha, buf, 1);
-    }
-  }
-
-  u8 digest[SHA256_SIZE];
-  SHA256_Final(digest, &sha);
-  return base64(digest, SHA256_SIZE);
-}
-
-template <typename E>
-static void send_fd(Context<E> &ctx, i64 conn, i64 fd) {
-  struct iovec iov;
-  char dummy = '1';
-  iov.iov_base = &dummy;
-  iov.iov_len = 1;
-
-  struct msghdr msg = {};
-  msg.msg_iov = &iov;
-  msg.msg_iovlen = 1;
-
-  char buf[CMSG_SPACE(sizeof(int))];
-  msg.msg_control = buf;
-  msg.msg_controllen = CMSG_LEN(sizeof(int));
-
-  struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
-  cmsg->cmsg_level = SOL_SOCKET;
-  cmsg->cmsg_type = SCM_RIGHTS;
-  cmsg->cmsg_len = CMSG_LEN(sizeof(int));
-  *(int *)CMSG_DATA(cmsg) = fd;
-
-  if (sendmsg(conn, &msg, 0) == -1)
-    Fatal(ctx) << "sendmsg failed: " << errno_string();
-}
-
-template <typename E>
-static i64 recv_fd(Context<E> &ctx, i64 conn) {
-  struct iovec iov;
-  char buf[1];
-  iov.iov_base = buf;
-  iov.iov_len = sizeof(buf);
-
-  struct msghdr msg = {};
-  msg.msg_iov = &iov;
-  msg.msg_iovlen = 1;
-
-  char cmsgbuf[CMSG_SPACE(sizeof(int))];
-  msg.msg_control = (caddr_t)cmsgbuf;
-  msg.msg_controllen = sizeof(cmsgbuf);
-
-  i64 len = recvmsg(conn, &msg, 0);
-  if (len <= 0)
-    Fatal(ctx) << "recvmsg failed: " << errno_string();
-
-  struct cmsghdr *cmsg;
-  cmsg = CMSG_FIRSTHDR(&msg);
-  return *(int *)CMSG_DATA(cmsg);
-}
-
-template <typename E>
-void try_resume_daemon(Context<E> &ctx) {
-  i64 conn = socket(AF_UNIX, SOCK_STREAM, 0);
-  if (conn == -1)
-    Fatal(ctx) << "socket failed: " << errno_string();
-
-  std::string path = "/tmp/mold-" + compute_sha256(ctx.cmdline_args);
-
-  struct sockaddr_un name = {};
-  name.sun_family = AF_UNIX;
-  memcpy(name.sun_path, path.data(), path.size());
-
-  if (connect(conn, (struct sockaddr *)&name, sizeof(name)) != 0) {
-    close(conn);
-    return;
-  }
-
-  send_fd(ctx, conn, STDOUT_FILENO);
-  send_fd(ctx, conn, STDERR_FILENO);
-
-  char buf[1];
-  i64 r = read(conn, buf, 1);
-  close(conn);
-  if (r == 1)
-    exit(0);
-}
-
-template <typename E>
-void daemonize(Context<E> &ctx, std::function<void()> *wait_for_client,
-               std::function<void()> *on_complete) {
-  if (daemon(1, 0) == -1)
-    Fatal(ctx) << "daemon failed: " << errno_string();
-
-  i64 sock = socket(AF_UNIX, SOCK_STREAM, 0);
-  if (sock == -1)
-    Fatal(ctx) << "socket failed: " << errno_string();
-
-  socket_tmpfile =
-    strdup(("/tmp/mold-" + compute_sha256(ctx.cmdline_args)).c_str());
-
-  struct sockaddr_un name = {};
-  name.sun_family = AF_UNIX;
-  strcpy(name.sun_path, socket_tmpfile);
-
-  u32 orig_mask = umask(0177);
-
-  if (bind(sock, (struct sockaddr *)&name, sizeof(name)) == -1) {
-    if (errno != EADDRINUSE)
-      Fatal(ctx) << "bind failed: " << errno_string();
-
-    unlink(socket_tmpfile);
-    if (bind(sock, (struct sockaddr *)&name, sizeof(name)) == -1)
-      Fatal(ctx) << "bind failed: " << errno_string();
-  }
-
-  umask(orig_mask);
-
-  if (listen(sock, 0) == -1)
-    Fatal(ctx) << "listen failed: " << errno_string();
-
-  static i64 conn = -1;
-
-  *wait_for_client = [=, &ctx] {
-    fd_set rfds;
-    FD_ZERO(&rfds);
-    FD_SET(sock, &rfds);
-
-    struct timeval tv;
-    tv.tv_sec = DAEMON_TIMEOUT;
-    tv.tv_usec = 0;
-
-    i64 res = select(sock + 1, &rfds, NULL, NULL, &tv);
-    if (res == -1)
-      Fatal(ctx) << "select failed: " << errno_string();
-
-    if (res == 0) {
-      std::cout << "timeout\n";
-      exit(0);
-    }
-
-    conn = accept(sock, NULL, NULL);
-    if (conn == -1)
-      Fatal(ctx) << "accept failed: " << errno_string();
-    unlink(socket_tmpfile);
-
-    dup2(recv_fd(ctx, conn), STDOUT_FILENO);
-    dup2(recv_fd(ctx, conn), STDERR_FILENO);
-  };
-
-  *on_complete = [=] {
-    char buf[] = {1};
-    int n = write(conn, buf, 1);
-    assert(n == 1);
-  };
-}
-
 static std::string get_self_path() {
   return std::filesystem::read_symlink("/proc/self/exe");
 }
@@ -307,9 +121,6 @@ void process_run_subcommand(Context<E> &ctx, int argc, char **argv) {
 }
 
 #define INSTANTIATE(E)                                                  \
-  template void try_resume_daemon(Context<E> &);                        \
-  template void daemonize(Context<E> &, std::function<void()> *,        \
-                          std::function<void()> *);                     \
   template void process_run_subcommand(Context<E> &, int, char **)
 
 INSTANTIATE_ALL;