[lldb] Add support for escaping zsh arguments

[teemperor]

Summary

LLDB supports having globbing regexes in the process launch arguments that will be resolved
using the user's shell. This requires that we pass the launch args to the shell and then read
back the expanded arguments using LLDB's argdumper utility.

As the shell will not just expand the globbing regexes but all special characters, we need to
escape all non-globbing charcters such as $, &, <, >, etc. as those otherwise are interpreted and
removed in the step where we expand the globbing characters. Also because the special characters
are shell-specific, LLDB needs to maintain a list of all the characters that need to be escaped for
each specific shell.

This patch adds the list of special characters that need to be escaped for zsh. Without this patch
on systems where zsh is the user's shell (like on all macOS systems) having any of these special
characters in your arguments or path to the binary will cause the process launch to fail. E.g.,
lldb -- ./calc 1<2 is failing without this patch. The same happens if the absolute path to calc is
in a directory that contains for example parentheses or other special characters.

[teemperor]

• Remove $ so that env variables will be expanded.

[JDevlieghere]

LGTM.

lldb/source/Utility/Args.cpp

390

What about fish?

[JDevlieghere]

lldb/source/Utility/Args.cpp

390

I see D104635

[teemperor]

• Add pipe and backslash

lldb/source/Utility/Args.cpp

std::string Args::GetShellSafeArgument(const FileSpec &shell,
                                        llvm::StringRef unsafe_arg) {
   struct ShellDescriptor {
     ConstString m_basename;
     llvm::StringRef m_escapables;
   };
 
   static ShellDescriptor g_Shells[] = {{ConstString("bash"), " '\"<>()&"},
                                        {ConstString("tcsh"), " '\"<>()&$"},
+                                       {ConstString("zsh"), " '\"<>()&;\\|"},
                                        {ConstString("sh"), " '\"<>()&"}};
 
   // safe minimal set
   llvm::StringRef escapables = " '\"";
 
   if (auto basename = shell.GetFilename()) {
     for (const auto &Shell : g_Shells) {
       if (Shell.m_basename == basename) {
         escapables = Shell.m_escapables;

lldb/unittests/Utility/ArgsTest.cpp

 
 TEST(ArgsTest, GetShellSafeArgument) {
   // Try escaping with bash at start/middle/end of the argument.
   FileSpec bash("/bin/bash", FileSpec::Style::posix);
   EXPECT_EQ(Args::GetShellSafeArgument(bash, "\"b"), "\\\"b");
   EXPECT_EQ(Args::GetShellSafeArgument(bash, "a\""), "a\\\"");
   EXPECT_EQ(Args::GetShellSafeArgument(bash, "a\"b"), "a\\\"b");
 
+  FileSpec zsh("/bin/zsh", FileSpec::Style::posix);
+  EXPECT_EQ(Args::GetShellSafeArgument(zsh, R"('";()<>&|\)"),
+            R"(\'\"\;\(\)\<\>\&\|\\)");
+  // Normal characters and expressions that shouldn't be escaped.
+  EXPECT_EQ(Args::GetShellSafeArgument(zsh, "aA$1*"), "aA$1*");
+
   // String that doesn't need to be escaped
   EXPECT_EQ(Args::GetShellSafeArgument(bash, "a"), "a");
 
   // Try escaping with tcsh and the tcsh-specific "$" escape.
   FileSpec tcsh("/bin/tcsh", FileSpec::Style::posix);
   EXPECT_EQ(Args::GetShellSafeArgument(tcsh, "a$b"), "a\\$b");
   // Bash however doesn't need escaping for "$".
   EXPECT_EQ(Args::GetShellSafeArgument(bash, "a$b"), "a$b");
 
   // Try escaping with an unknown shell.
   FileSpec unknown_shell("/bin/unknown_shell", FileSpec::Style::posix);
   EXPECT_EQ(Args::GetShellSafeArgument(unknown_shell, "a'b"), "a\\'b");
   EXPECT_EQ(Args::GetShellSafeArgument(unknown_shell, "a\"b"), "a\\\"b");
 }