Fix for GNU project, replace Single Line Comments

sh.c

@@ -3,11 +3,25 @@
 #include <string.h>
 #include <unistd.h>
 #include <sys/wait.h>
-#include <linux/limits.h>
 #include <signal.h>
 #include <libgen.h>
+#include <errno.h>
 
-#define ARG_SEP " " //Argument separator for commands
+/*
+  Gods damn it, of course we have to have special shit
+  just for the fucking GNU Project. Fuckers can't let
+  anything be done to standard unless they fucking want
+  to or you beg them to let you, can they?
+
+  -Kat
+*/
+#ifdef __GLIBC__
+#define __USE_POSIX
+#define __USE_POSIX2
+#endif
+#include <limits.h>
+
+#define ARG_SEP " " /* Argument separator for commands */
 #define PROMPT " $ "
 
 char** create_argv(char* command);
@@ -16,12 +30,12 @@ char* prompt();
 int cd(char* path);
 
 int main() {
-  char** argv; //The command with arguments
+  char** argv; /* The command with arguments */
   char* user_input;
   pid_t child_pid;
-  int stat_loc; //??? (Needed for waitpid)
+  int stat_loc; /* ??? (Needed for waitpid) */
 
-  signal(SIGINT, SIG_IGN); //Tell vsh to ignore SIGINT (^C)
+  signal(SIGINT, SIG_IGN); /* Tell vsh to ignore SIGINT (^C) */
 
   while(1) {
     user_input = prompt();
@@ -31,7 +45,7 @@ int main() {
       if(cd(&user_input[3]) < 0) {
 	perror(argv[1]);
       }
-      //causes the fork to get skipped
+      /* causes the fork to get skipped */
       continue;
     }
     else if(strcmp(argv[0], "exit") == 0 ||
@@ -41,12 +55,23 @@ int main() {
 
     child_pid = fork();
     if(child_pid < 0) {
-      //If the child couldn't run, assume no memory
-      perror("Out of memory");
-      exit(1);
+      /* Could not start child process. Check why and error out. */
+      if(errno == EAGAIN) {
+	perror("Could not execute command: insufficient resources");
+	exit(1);
+      }
+      else if(errno == ENOMEM) {
+	/* Is this out of RAM or out of storage? */
+	perror("Could not execute command: insufficient storage space");
+	exit(1);
+      }
+      else {
+	perror("Could not execute command: unknown failure");
+	exit(1);
+      }
     }
     else if(child_pid == 0) {
-      //If we are the child, allow ^C
+      /* We are the child, so allow ^C */
       signal(SIGINT, SIG_DFL);
       if(execvp(argv[0], argv) < 0) {
 	perror(argv[0]);
@@ -54,6 +79,7 @@ int main() {
       }
     }
     else {
+      /* Wait for the child to finish */
       waitpid(child_pid, &stat_loc, WUNTRACED);
     }
 
@@ -71,8 +97,7 @@ char** create_argv(char* command) {
   
   char** argv = calloc(argc, sizeof(*argv));
   if(argv == NULL) {
-    //If couldn't allocate argv, assume no memory
-    perror("Out of memory");
+    perror("Unable to parse command: could not allocate memory");
     exit(1);
   }
 
@@ -82,7 +107,7 @@ char** create_argv(char* command) {
     i++;
   }
 
-  //Set last item in argv to NULL, since execvp requires it
+  /* Set last item in argv to NULL, since execvp requires it */
   argv[i] = NULL;
   return argv;
 }
@@ -94,15 +119,13 @@ char* prompt() {
   char prompt[PATH_MAX + 5] = "";
   strcat(prompt, bname);
   strcat(prompt, PROMPT);
-  char* input = calloc(512, sizeof(*input));
+  char* input = calloc(LINE_MAX, sizeof(*input));
   if(input == NULL) {
-    //If input allocate failed, assume no memory
-    perror("Out of memory");
+    perror("Unable to read command: could not allocate memory");
     exit(1);
   }
   printf("%s", prompt);
-  fgets(input, 512, stdin);
-  //Is 512 enough? What about really long commands?
+  fgets(input, LINE_MAX, stdin);
   input[strcspn(input, "\r\n")] = '\0';
   return input;
 }