Shell: Support semicolons for separating commands

Shell/Parser.cpp

@@ -22,6 +22,13 @@ void Parser::commit_subcommand()
     m_subcommands.append({ move(m_tokens), move(m_redirections), {} });
 }
 
+void Parser::commit_command()
+{
+    if (m_subcommands.is_empty())
+        return;
+    m_commands.append({ move(m_subcommands) });
+}
+
 void Parser::do_pipe()
 {
     m_redirections.append({ Redirection::Pipe, STDOUT_FILENO });
@@ -38,7 +45,7 @@ void Parser::begin_redirect_write(int fd)
     m_redirections.append({ Redirection::FileWrite, fd });
 }
 
-Vector<Subcommand> Parser::parse()
+Vector<Command> Parser::parse()
 {
     for (int i = 0; i < m_input.length(); ++i) {
         char ch = m_input.characters()[i];
@@ -48,6 +55,12 @@ Vector<Subcommand> Parser::parse()
                 commit_token();
                 break;
             }
+            if (ch == ';') {
+                commit_token();
+                commit_subcommand();
+                commit_command();
+                break;
+            }
             if (ch == '|') {
                 commit_token();
                 if (m_tokens.is_empty()) {
@@ -140,6 +153,7 @@ Vector<Subcommand> Parser::parse()
     }
     commit_token();
     commit_subcommand();
+    commit_command();
 
     if (!m_subcommands.is_empty()) {
         for (auto& redirection : m_subcommands.last().redirections) {
@@ -150,5 +164,5 @@ Vector<Subcommand> Parser::parse()
         }
     }
 
-    return move(m_subcommands);
+    return move(m_commands);
 }

Shell/Parser.h

@@ -27,6 +27,10 @@ struct Subcommand {
     Vector<Rewiring> rewirings;
 };
 
+struct Command {
+    Vector<Subcommand> subcommands;
+};
+
 class Parser {
 public:
     explicit Parser(const String& input)
@@ -34,11 +38,12 @@ public:
     {
     }
 
-    Vector<Subcommand> parse();
+    Vector<Command> parse();
 
 private:
     void commit_token();
     void commit_subcommand();
+    void commit_command();
     void do_pipe();
     void begin_redirect_read(int fd);
     void begin_redirect_write(int fd);
@@ -53,6 +58,7 @@ private:
     State m_state { Free };
     String m_input;
 
+    Vector<Command> m_commands;
     Vector<Subcommand> m_subcommands;
     Vector<String> m_tokens;
     Vector<Redirection> m_redirections;

Shell/main.cpp

@@ -20,7 +20,7 @@
 #include <termios.h>
 #include <unistd.h>
 
-//#define SH_DEBUG
+#define SH_DEBUG
 
 GlobalState g;
 static LineEditor editor;
@@ -320,17 +320,18 @@ static int run_command(const String& cmd)
     if (cmd.is_empty())
         return 0;
 
-    auto subcommands = Parser(cmd).parse();
+    auto commands = Parser(cmd).parse();
 
 #ifdef SH_DEBUG
-    for (int i = 0; i < subcommands.size(); ++i) {
+    for (auto& command : commands) {
+        for (int i = 0; i < command.subcommands.size(); ++i) {
             for (int j = 0; j < i; ++j)
                 dbgprintf("    ");
-        for (auto& arg : subcommands[i].args) {
+            for (auto& arg : command.subcommands[i].args) {
                 dbgprintf("<%s> ", arg.characters());
             }
             dbgprintf("\n");
-        for (auto& redirecton : subcommands[i].redirections) {
+            for (auto& redirecton : command.subcommands[i].redirections) {
                 for (int j = 0; j < i; ++j)
                     dbgprintf("    ");
                 dbgprintf("  ");
@@ -352,15 +353,28 @@ static int run_command(const String& cmd)
                 }
             }
         }
+        dbgprintf("\n");
+    }
 #endif
 
-    if (subcommands.is_empty())
-        return 0;
+    struct termios trm;
+    tcgetattr(0, &trm);
+
+    struct SpawnedProcess {
+        String name;
+        pid_t pid;
+    };
+
+    int return_value = 0;
+
+    for (auto& command : commands) {
+        if (command.subcommands.is_empty())
+            continue;
 
         FileDescriptionCollector fds;
 
-    for (int i = 0; i < subcommands.size(); ++i) {
-        auto& subcommand = subcommands[i];
+        for (int i = 0; i < command.subcommands.size(); ++i) {
+            auto& subcommand = command.subcommands[i];
             for (auto& redirection : subcommand.redirections) {
                 switch (redirection.type) {
                 case Redirection::Pipe: {
@@ -371,7 +385,7 @@ static int run_command(const String& cmd)
                         return 1;
                     }
                     subcommand.rewirings.append({ STDOUT_FILENO, pipefd[1] });
-                auto& next_command = subcommands[i + 1];
+                    auto& next_command = command.subcommands[i + 1];
                     next_command.rewirings.append({ STDIN_FILENO, pipefd[0] });
                     fds.add(pipefd[0]);
                     fds.add(pipefd[1]);
@@ -411,20 +425,12 @@ static int run_command(const String& cmd)
             }
         }
 
-    struct termios trm;
-    tcgetattr(0, &trm);
-
-    struct SpawnedProcess {
-        String name;
-        pid_t pid;
-    };
-
         Vector<SpawnedProcess> children;
 
         CommandTimer timer;
 
-    for (int i = 0; i < subcommands.size(); ++i) {
-        auto& subcommand = subcommands[i];
+        for (int i = 0; i < command.subcommands.size(); ++i) {
+            auto& subcommand = command.subcommands[i];
             Vector<String> argv_string = process_arguments(subcommand.args);
             Vector<const char*> argv;
             argv.ensure_capacity(argv_string.size());
@@ -450,7 +456,7 @@ static int run_command(const String& cmd)
                 tcsetpgrp(0, getpid());
                 for (auto& rewiring : subcommand.rewirings) {
 #ifdef SH_DEBUG
-                dbgprintf("in %s<%d>, dup2(%d, %d)\n", argv[0], getpid(), redirection.rewire_fd, redirection.fd);
+                    dbgprintf("in %s<%d>, dup2(%d, %d)\n", argv[0], getpid(), rewiring.rewire_fd, rewiring.fd);
 #endif
                     int rc = dup2(rewiring.rewire_fd, rewiring.fd);
                     if (rc < 0) {
@@ -486,7 +492,6 @@ static int run_command(const String& cmd)
 #endif
 
         int wstatus = 0;
-    int return_value = 0;
 
         for (int i = 0; i < children.size(); ++i) {
             auto& child = children[i];
@@ -513,6 +518,7 @@ static int run_command(const String& cmd)
                 }
             } while (errno == EINTR);
         }
+    }
 
     // FIXME: Should I really have to tcsetpgrp() after my child has exited?
     //        Is the terminal controlling pgrp really still the PGID of the dead process?