formatting tweaks

a759b8a4 · rsc · 2868ca0f · a759b8a4
--- a/sh.c
+++ b/sh.c
@@ -49,19 +49,9 @@ struct backcmd {
  struct cmd *cmd;
 };
-struct cmd *parsecmd(char*);
+int fork1(void);  // Fork but panics on failure.
 void panic(char*);
+struct cmd *parsecmd(char*);
-int
-fork1(void)
-{
-  int pid;
-  pid = fork();
-  if(pid == -1)
-    panic("fork");
-  return pid;
-}
 // Execute cmd.  Never returns.
 void
@@ -99,6 +89,14 @@ runcmd(struct cmd *cmd)
    runcmd(rcmd->cmd);
    break;
+  case LIST:
+    lcmd = (struct listcmd*)cmd;
+    if(fork1() == 0)
+      runcmd(lcmd->left);
+    wait();
+    runcmd(lcmd->right);
+    break;
  case PIPE:
    pcmd = (struct pipecmd*)cmd;
    if(pipe(p) < 0)
@@ -123,14 +121,6 @@ runcmd(struct cmd *cmd)
    wait();
    break;
-  case LIST:
-    lcmd = (struct listcmd*)cmd;
-    if(fork1() == 0)
-      runcmd(lcmd->left);
-    wait();
-    runcmd(lcmd->right);
-    break;
  case BACK:
    bcmd = (struct backcmd*)cmd;
    if(fork1() == 0)
@@ -155,7 +145,17 @@ int
 main(void)
 {
  static char buf[100];
+  int fd;
+  // Assumes three file descriptors open.
+  while((fd = open("console", O_RDWR)) >= 0){
+    if(fd >= 3){
+      close(fd);
+      break;
+    }
+  }
+  // Read and run input commands.
  while(getcmd(buf, sizeof(buf)) >= 0) {
    if(fork1() == 0)
      runcmd(parsecmd(buf));
@@ -171,6 +171,18 @@ panic(char *s)
  exit();
 }
+int
+fork1(void)
+{
+  int pid;
+  pid = fork();
+  if(pid == -1)
+    panic("fork");
+  return pid;
+}
+//PAGEBREAK!
 // Constructors
 struct cmd*
@@ -237,25 +249,13 @@ backcmd(struct cmd *subcmd)
  cmd->cmd = subcmd;
  return (struct cmd*)cmd;
 }
+//PAGEBREAK!
 // Parsing
 char whitespace[] = " \t\r\n\v";
 char symbols[] = "<|>&;()";
 int
-peek(char **ps, char *es, char *toks)
-{
-  char *s;
-  s = *ps;
-  while(s < es && strchr(whitespace, *s))
-    s++;
-  *ps = s;
-  return *s && strchr(toks, *s);
-}
-int
 gettoken(char **ps, char *es, char **q, char **eq)
 {
  char *s;
@@ -300,12 +300,22 @@ gettoken(char **ps, char *es, char **q, char **eq)
  return ret;
 }
-void nulterminate(struct cmd*);
+int
+peek(char **ps, char *es, char *toks)
+{
+  char *s;
+  s = *ps;
+  while(s < es && strchr(whitespace, *s))
+    s++;
+  *ps = s;
+  return *s && strchr(toks, *s);
+}
 struct cmd *parseline(char**, char*);
 struct cmd *parsepipe(char**, char*);
-struct cmd *parseredirs(struct cmd*, char**, char*);
-struct cmd *parseblock(char**, char*);
 struct cmd *parseexec(char**, char*);
+struct cmd *nulterminate(struct cmd*);
 struct cmd*
 parsecmd(char *s)
@@ -355,22 +365,6 @@ parsepipe(char **ps, char *es)
 }
 struct cmd*
-parseblock(char **ps, char *es)
-{
-  struct cmd *cmd;
-  if(!peek(ps, es, "("))
-    panic("parseblock");
-  gettoken(ps, es, 0, 0);
-  cmd = parseline(ps, es);
-  if(!peek(ps, es, ")"))
-    panic("syntax - missing )");
-  gettoken(ps, es, 0, 0);
-  cmd = parseredirs(cmd, ps, es);
-  return cmd;
-}
-struct cmd*
 parseredirs(struct cmd *cmd, char **ps, char *es)
 {
  int tok;
@@ -396,6 +390,22 @@ parseredirs(struct cmd *cmd, char **ps, char *es)
 }
 struct cmd*
+parseblock(char **ps, char *es)
+{
+  struct cmd *cmd;
+  if(!peek(ps, es, "("))
+    panic("parseblock");
+  gettoken(ps, es, 0, 0);
+  cmd = parseline(ps, es);
+  if(!peek(ps, es, ")"))
+    panic("syntax - missing )");
+  gettoken(ps, es, 0, 0);
+  cmd = parseredirs(cmd, ps, es);
+  return cmd;
+}
+struct cmd*
 parseexec(char **ps, char *es)
 {
  char *q, *eq;
@@ -429,7 +439,7 @@ parseexec(char **ps, char *es)
 }
 // NUL-terminate all the counted strings.
-void
+struct cmd:
 nulterminate(struct cmd *cmd)
 {
  int i;
@@ -440,7 +450,7 @@ nulterminate(struct cmd *cmd)
  struct redircmd *rcmd;
  if(cmd == 0)
-    return;
+    return 0;
  switch(cmd->type){
  case EXEC:
@@ -472,4 +482,5 @@ nulterminate(struct cmd *cmd)
    nulterminate(bcmd->cmd);
    break;
  }
+  return cmd;
 }