From 9fab3e050f7b4e1816a966e7ce74fce74b991709 Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@operamail.com>
Date: Mon, 18 Nov 2013 19:39:48 +0100
Subject: more flexible
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Signed-off-by: Mattias Andrée <maandree@operamail.com>
---
 Makefile       | 23 ++++++++++++++++++++++-
 src/cerberus.c | 10 +++++-----
 src/security.c | 22 +++++++++++-----------
 3 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/Makefile b/Makefile
index 79fb87f..1c64f75 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,26 @@
+BIN = /bin
+DEV = /dev
+
+EXTRA_CPP_FLAGS = 
+# -DOWN_VCS -DOWN_VCSA -DUSE_TTY_GROUP
+
+TTY_GROUP = tty
+DEFAULT_HOME = /
+DEFAULT_SHELL = $(BIN)/sh
+DEFAULT_TERM = dumb
+VCS = $(DEV)/vcs
+VCSA = $(DEV)/vcsa
+
+H = \#
+VCS_LEN = $(shell vcs="$(VCS)" ; echo "$${$(H)vcs}")
+VCSA_LEN = $(shell vcsa="$(VCSA)" ; echo "$${$(H)vcsa}")
+VCS_VCSA_LEN = $(shell (echo $(VCS_LEN) ; echo $(VCSA_LEN)) | sort -n | tail -n 1)
+
+STR_DEFS = TTY_GROUP DEFAULT_HOME DEFAULT_SHELL DEFAULT_TERM
+INT_DEFS = VCS_LEN VCSA_LEN VCS_VCSA_LEN
+
 OPTIMISE = -Os
-CPPFLAGS = 
+CPPFLAGS = $(EXTRA_CPP_FLAGS) $(foreach D, $(INT_DEFS), -D'$(D)=$($(D))') $(foreach D, $(STR_DEFS), -D'$(D)="$($(D))"')
 LDFLAGS = 
 CFLAGS = -std=gnu99 -Wall -Wextra
 
diff --git a/src/cerberus.c b/src/cerberus.c
index 987a497..8d2a052 100644
--- a/src/cerberus.c
+++ b/src/cerberus.c
@@ -132,7 +132,7 @@ int main(int argc, char** argv)
   
   /* Make sure nopony is spying */
   #ifdef USE_TTY_GROUP
-  if ((group = getgrnam("tty")))
+  if ((group = getgrnam(TTY_GROUP)))
     tty_group = group->gr_gid;
   #endif
   secure_tty(tty_group);
@@ -193,18 +193,18 @@ int main(int argc, char** argv)
   if (chdir(entry->pw_dir))
     {
       perror("chdir");
-      if (chdir("/"))
+      if (chdir(DEFAULT_HOME))
 	{
 	  perror("chdir");
 	  sleep(ERROR_SLEEP);
 	  return 1;
 	}
-      entry->pw_dir = "/";
+      entry->pw_dir = DEFAULT_HOME;
     }
   
   /* Make sure the shell to use is definied */
   if ((entry->pw_shell && *(entry->pw_shell)) == 0)
-    entry->pw_shell = "/bin/sh";
+    entry->pw_shell = DEFAULT_SHELL;
   
   /* Set environment variables */
   {
@@ -242,7 +242,7 @@ int main(int argc, char** argv)
     setenv("USER", entry->pw_name, 1);
     setenv("LOGUSER", entry->pw_name, 1);
     setenv("SHELL", entry->pw_shell, 1);
-    setenv("TERM", term ?: "dumb", 1);
+    setenv("TERM", term ?: DEFAULT_TERM, 1);
     if (term)
       free(term);
     
diff --git a/src/security.c b/src/security.c
index 1e1dd9e..a273cf0 100644
--- a/src/security.c
+++ b/src/security.c
@@ -99,13 +99,13 @@ void chown_tty(uid_t owner, gid_t group, int with_fail)
     if (ioctl(STDIN_FILENO, VT_GETSTATE, &vtstat) == 0)
       {
 	int n = vtstat.v_active;
-	char _vcs[16];
-	char _vcsa[16];
+	char _vcs[VCS_VCSA_LEN];
+	char _vcsa[VCS_VCSA_LEN];
 	
 	char* vcs = _vcs;
 	char* vcsa = _vcsa;
-	vcs += 16;
-	vcsa += 16;
+	vcs += VCS_VCSA_LEN;
+	vcsa += VCS_VCSA_LEN;
 	
 	if (n)
 	  {
@@ -116,18 +116,18 @@ void chown_tty(uid_t owner, gid_t group, int with_fail)
 		n /= 10;
 	      }
 	    
-	    vcs -= 8;
-	    vcsa -= 9;
-	    strcpy(vcs,  "/dev/vcs");
-	    strcpy(vcsa, "/dev/vcsa");
+	    vcs -= VCS_LEN;
+	    vcsa -= VCSA_LEN;
+	    strcpy(vcs,  VCS);
+	    strcpy(vcsa, VCSA);
 	    
 	    #ifdef OWN_VCS
-	      if (chown(vcs,  owner, group) && with_fail)  fail("chown");
-	      if (chmod(vcs,  TTY_PERM) && with_fail)  fail("chmod");
+	      if (chown(vcs, owner, group) && with_fail)  fail("chown");
+	      if (chmod(vcs, TTY_PERM)     && with_fail)  fail("chmod");
 	    #endif
 	    #ifdef OWN_VCSA
 	      if (chown(vcsa, owner, group) && with_fail)  fail("chown");
-	      if (chmod(vcsa, TTY_PERM) && with_fail)  fail("chmod");
+	      if (chmod(vcsa, TTY_PERM)     && with_fail)  fail("chmod");
 	    #endif
 	  }
       }
-- 
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