move exec instructions into login.c

Signed-off-by: Mattias Andrée <maandree@operamail.com>

4 files changed, 73 insertions, 55 deletions

diff --git a/src/cerberus.c b/src/cerberus.c
index ce60846..a4fa33d 100644
--- a/src/cerberus.c
+++ b/src/cerberus.c
@@ -40,6 +40,7 @@ int main(int argc, char** argv)
   struct group* group;
   #endif
   struct passwd* entry;
+  pid_t child_pid;
   
   
   /* Disable echoing */
@@ -190,75 +191,26 @@ int main(int argc, char** argv)
   set_environ(entry, preserve_env);
   
   {
-    pid_t pid = fork();
+    child_pid = fork();
     /* vfork cannot be used as the child changes the user,
        the parent would not be able to chown the TTY */
     
-    if (pid == -1)
+    if (child_pid == -1)
       {
 	perror("fork");
 	return 1;
       }
-    else if (pid == 0)
+    else if (child_pid == 0)
       {
-	int child_argc = 0;
-	char** child_argv = malloc(5 * sizeof(char*));
-	int n = 0;
-	char* sh = entry->pw_shell;
-	char* login_sh;
-        
 	/* Partial login */
 	/* TODO set supplemental groups */
 	set_user(entry);
-	
-	while (*(sh + n++))
-	  ;
-	
-	login_sh = malloc((n + (strchr(sh, ' ') ? 5 : 1)) * sizeof(char));
-	if (login_sh == NULL)
-	  {
-	    perror("malloc");
-	    sleep(ERROR_SLEEP);
-	    _exit(1);
-	  }
-	
-	if (strchr(sh, ' '))
-	  {
-	    login_sh += 5;
-	    strcpy(login_sh, "exec ");
-	    *(login_sh + n) = 0;
-	    
-	    *(child_argv + child_argc++) = DEFAULT_SHELL;
-	    *(child_argv + child_argc++) = "-" DEFAULT_SH;
-	    *(child_argv + child_argc++) = "-c";
-	    *(child_argv + child_argc++) = login_sh - 5;
-	  }
-	else
-	  {
-	    int i;
-	    for (i = n - 1; i >= 0; i--)
-	      if (*(sh + i) == '/')
-		{
-		  i++;
-		  break;
-		}
-	    
-	    login_sh = malloc((n + 1) * sizeof(char));
-	    *login_sh++ = '-';
-	    strcpy(login_sh, sh + i);
-	    *(login_sh + n) = 0;
-	    
-	    *(child_argv + child_argc++) = sh;
-	    *(child_argv + child_argc++) = login_sh - 1;
-	  }
-        
-	*(child_argv + child_argc) = NULL;
-        execvp(*child_argv, child_argv + 1);
+	exec_shell(entry);
       }
     else
       {
 	int _status;
-	waitpid(pid, &_status, 0);
+	waitpid(child_pid, &_status, 0);
 	
 	/* Reset terminal ownership and mode */
 	chown_tty(0, tty_group, 0);
diff --git a/src/cerberus.h b/src/cerberus.h
index b5501a4..e195245 100644
--- a/src/cerberus.h
+++ b/src/cerberus.h
@@ -24,7 +24,6 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <signal.h>
-#include <string.h>
 #include <pwd.h>
 #include <errno.h>
 #include <sys/wait.h>
diff --git a/src/login.c b/src/login.c
index 46bf4e2..3ad1204 100644
--- a/src/login.c
+++ b/src/login.c
@@ -20,6 +20,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <string.h>
 
 #include "config.h"
 
@@ -135,3 +136,62 @@ void set_environ(struct passwd* entry, char preserve_env)
     free(term);
 }
 
+
+/**
+ * Replace the current image with the user's login shell
+ * 
+ * @param  entry  The user entry in the password file
+ */
+void exec_shell(struct passwd* entry)
+{
+  int child_argc = 0;
+  char** child_argv = malloc(5 * sizeof(char*));
+  long n = 0;
+  char* sh = entry->pw_shell;
+  char* login_sh;
+  
+  while (*(sh + n++))
+    ;
+  
+  login_sh = malloc((n + (strchr(sh, ' ') ? 5 : 1)) * sizeof(char));
+  if (login_sh == NULL)
+    {
+      perror("malloc");
+      sleep(ERROR_SLEEP);
+      _exit(1);
+    }
+  
+  if (strchr(sh, ' '))
+    {
+      login_sh += 5;
+      strcpy(login_sh, "exec ");
+      *(login_sh + n) = 0;
+      
+      *(child_argv + child_argc++) = DEFAULT_SHELL;
+      *(child_argv + child_argc++) = "-" DEFAULT_SH;
+      *(child_argv + child_argc++) = "-c";
+      *(child_argv + child_argc++) = login_sh - 5;
+    }
+  else
+    {
+      int i;
+      for (i = n - 1; i >= 0; i--)
+	if (*(sh + i) == '/')
+	  {
+	    i++;
+	    break;
+	  }
+      
+      login_sh = malloc((n + 1) * sizeof(char));
+      *login_sh++ = '-';
+      strcpy(login_sh, sh + i);
+      *(login_sh + n) = 0;
+      
+      *(child_argv + child_argc++) = sh;
+      *(child_argv + child_argc++) = login_sh - 1;
+    }
+  
+  *(child_argv + child_argc) = NULL;
+  execvp(*child_argv, child_argv + 1);
+}
+
diff --git a/src/login.h b/src/login.h
index 14014f2..e335e7c 100644
--- a/src/login.h
+++ b/src/login.h
@@ -51,6 +51,13 @@ void ensure_shell(struct passwd* entry);
  */
 void set_environ(struct passwd* entry, char preserve_env);
 
+/**
+ * Replace the current image with the user's login shell
+ * 
+ * @param  entry  The user entry in the password file
+ */
+void exec_shell(struct passwd* entry);
+
 
 #endif