From 06a02a3a50baf261a0f1c998bfd02269c3ed45de Mon Sep 17 00:00:00 2001
From: "Douglas B. Rumbaugh" <doug@douglasrumbaugh.com>
Date: Fri, 31 Oct 2025 23:41:32 -0400
Subject: Initial commit

---
 src/command.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 src/command.c

(limited to 'src/command.c')

diff --git a/src/command.c b/src/command.c
new file mode 100644
index 0000000..73a2027
--- /dev/null
+++ b/src/command.c
@@ -0,0 +1,103 @@
+/*
+ * 
+ */
+
+#include "command.h"
+#include "config.h"
+#include "lexer.h"
+#include <stdio.h>
+#include <unistd.h>
+
+command *commands_from_tokens(token *parsed_cmdstr, size_t *cnt) {
+
+  command *cmd_head = calloc(1, sizeof(command));
+  command *cmd = cmd_head;
+  size_t arg_cnt = 1;
+
+  *cnt = 0;
+
+  token *prev_tkn = NULL;
+
+  for (token *tkn = parsed_cmdstr; tkn; prev_tkn = tkn, tkn = tkn->next) {
+    if (tkn->type == TKN_COMMAND) {
+      cmd->command = tkn->text;
+      cmd->args[0] = tkn->text;
+      arg_cnt = 1;
+      (*cnt)++;
+    } else if (tkn->type == TKN_ARG) {
+      cmd->args[arg_cnt++] = tkn->text;
+    } else if (tkn->type == TKN_FILENAME) {
+      if (prev_tkn->type == TKN_IN_REDIR) {
+        cmd->infile = tkn->text;
+      } else {
+        cmd->outfile = tkn->text;
+      }
+    } else if (tkn->type == TKN_PIPE) {
+      cmd->next = calloc(1, sizeof(command));
+      cmd->next->read_pipe = cmd->pipe;
+      cmd = cmd->next;
+    }
+    
+  }
+
+  return cmd_head;
+}
+
+void print_commands(FILE *file, command *cmds) {
+  for (command *cmd=cmds; cmd; cmd = cmd->next) {
+    fprintf(file, "Command: %s\n", cmd->command);
+    fprintf(file, "\t");
+    for (size_t i=0; i<MAX_ARGUMENT_CNT; i++) {
+      fprintf(file, "%s ", cmd->args[i]);
+    }
+    fprintf(file, "\n\tInfile: %s\n\tOutfile: %s\n", cmd->infile, cmd->outfile);
+  }
+}
+
+void destroy_commands(command *cmds) {
+  command **cmd_ptr = &cmds->next;
+  while (*cmd_ptr) {
+    free(cmds);
+    cmds = *cmd_ptr;
+    cmd_ptr = &cmds->next;
+  }
+}
+
+pid_t execute_command(command *cmd) {
+  if (cmd->next) {
+    pipe(cmd->pipe);
+  }
+
+  pid_t res = fork();
+  if (res == 0) {
+    if (cmd->infile) {
+      if (!freopen(cmd->infile, "r", stdin)) {
+        perror("Could not open input file");
+        exit(EXIT_FAILURE);
+      }
+    } else if (cmd->read_pipe) {
+      dup2(*(cmd->read_pipe), STDIN_FILENO);
+      close(*(cmd->read_pipe));
+    }
+
+    if (cmd->outfile) {
+      if (!freopen(cmd->outfile, "w", stdout)) {
+        perror("Could not open output file");
+        exit(EXIT_FAILURE);
+      }
+    } else if (cmd->next) {
+      dup2(cmd->pipe[1], STDOUT_FILENO);
+      close(cmd->pipe[1]);
+    }
+
+    
+    int res = execvp(cmd->command, cmd->args);
+    perror("Could not run command");
+    exit(EXIT_FAILURE);
+  }  else if (res < 0) {
+    perror("Could not run command");
+  }
+
+  cmd->pid = res;
+  return res;
+}
-- 
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