From: Michael D. Lowis <mike.lowis@gentex.com>
Date: Fri, 11 Dec 2020 18:08:44 +0000 (-0500)
Subject: stubbed out shell with basic feedback loop
X-Git-Url: https://git.mdlowis.com/?a=commitdiff_plain;h=43a6e9b1aff790c01ee81a834ee0e4f046b0717f;p=proto%2Faos.git

stubbed out shell with basic feedback loop
---

diff --git a/bin/shell.c b/bin/shell.c
index 70021db..52fe958 100644
--- a/bin/shell.c
+++ b/bin/shell.c
@@ -2,163 +2,44 @@
 #include <sys/wait.h>
 #include <sys/types.h>
 
-#define LSH_TOK_BUFSIZE 64
-#define LSH_TOK_DELIM " \t\r\n\a"
-
-int cd(char **args)
-{
-    if (args[1] == NULL)
-    {
-        fprintf(stderr, "lsh: expected argument to \"cd\"\n");
-    }
-    else
-    {
-        if (chdir(args[1]) != 0)
-        {
-            perror("lsh");
-        }
-    }
-    return 1;
-}
-
-struct {
-    char* name;
-    int (*func)(char**);
-} Builtins[] = {
-    { .name = "cd", .func = cd }
-};
-
-int launch(char **args)
-{
-    pid_t pid = fork();
-    if (pid == 0)
-    {
-        // Child process
-        if (execvp(args[0], args) == -1)
-        {
-            perror("lsh");
-        }
-        exit(EXIT_FAILURE);
-    }
-    else if (pid < 0)
-    {
-        // Error forking
-        perror("lsh");
-    }
-    else
-    {
-        int status;
-        do
-        {
-            waitpid(pid, &status, WUNTRACED);
-        } while (!WIFEXITED(status) && !WIFSIGNALED(status));
-    }
-
-    return 1;
-}
-
-int execute(char **args)
-{
-    if (args[0] == NULL)
-    {
-        // An empty command was entered.
-        return 1;
-    }
-
-    for (size_t i = 0; i < nelem(Builtins); i++)
-    {
-        if (!strcmp(args[0], Builtins[i].name))
-        {
-            return Builtins[i].func(args);
-        }
-    }
-
-  return launch(args);
-}
-
-/**
-   @brief Read a line of input from stdin.
-   @return The line from stdin.
- */
-char *read_line(void)
+char* read_line(FILE* f)
 {
-    char *line = NULL;
-    size_t bufsize = 0; // have getline allocate a buffer for us
-    if (getline(&line, &bufsize, stdin) == -1)
+    char* line = efreadline(stdin);
+    size_t length = strlen(line);
+    if (length > 0 && line[length-1] == '\n')
     {
-        if (feof(stdin))
-        {
-            exit(EXIT_SUCCESS);  // We recieved an EOF
-        }
-        else
+        line[--length] = '\0';
+        if (length > 0 && line[length-1] == '\\')
         {
-            perror("lsh: getline\n");
-            exit(EXIT_FAILURE);
+            line[--length] = ' ';
+            char* rest = read_line(f);
+            char* lnpart = strmcat(line, rest, 0);
+            free(line);
+            free(rest);
+            line = lnpart;
         }
     }
     return line;
 }
 
-
-char** split_line(char *line)
-{
-    int bufsize = LSH_TOK_BUFSIZE, position = 0;
-    char **tokens = malloc(bufsize * sizeof(char*));
-    char *token, **tokens_backup;
-
-    if (!tokens)
-    {
-        fprintf(stderr, "lsh: allocation error\n");
-        exit(EXIT_FAILURE);
-    }
-
-    token = strtok(line, LSH_TOK_DELIM);
-    while (token != NULL)
-    {
-        tokens[position] = token;
-        position++;
-
-        if (position >= bufsize)
-        {
-            bufsize += LSH_TOK_BUFSIZE;
-            tokens_backup = tokens;
-            tokens = realloc(tokens, bufsize * sizeof(char*));
-            if (!tokens)
-            {
-                free(tokens_backup);
-                fprintf(stderr, "lsh: allocation error\n");
-                exit(EXIT_FAILURE);
-            }
-        }
-
-        token = strtok(NULL, LSH_TOK_DELIM);
-    }
-    tokens[position] = NULL;
-    return tokens;
-}
-
 int main(int argc, char **argv)
 {
     (void)argc;
     (void)argv;
 
-    // Load config files, if any.
+    /* load config files... */
 
-    int status = 0;
+    int running = 1;
     do
     {
         printf("> ");
-        char* line = read_line();
-        char** args = split_line(line);
-        status = execute(args);
-        (void)status;
+        char* line = read_line(stdin);
+        printf("'%s'\n", line);
         free(line);
-        free(args);
     }
-    while (status);
+    while (running);
 
-    // Perform any shutdown/cleanup.
+    /* shutdown and cleanup */
 
-    return EXIT_SUCCESS;
+    return 0;
 }
-