/*++ /* NAME /* clean_env 3 /* SUMMARY /* clean up the environment /* SYNOPSIS /* #include <clean_env.h> /* /* void clean_env(preserve_list) /* const char **preserve_list; /* DESCRIPTION /* clean_env() reduces the process environment to the bare minimum. /* The function takes a null-terminated list of arguments. /* Each argument specifies the name of an environment variable /* that should be preserved, or specifies a name=value that should /* be entered into the new environment. /* DIAGNOSTICS /* Fatal error: out of memory. /* SEE ALSO /* safe_getenv(3), guarded getenv() /* LICENSE /* .ad /* .fi /* The Secure Mailer license must be distributed with this software. /* AUTHOR(S) /* Wietse Venema /* IBM T.J. Watson Research /* P.O. Box 704 /* Yorktown Heights, NY 10598, USA /*--*/ /* System library. */ #include <sys_defs.h> #include <stdlib.h> #include <unistd.h> #include <string.h> /* Utility library. */ #include <msg.h> #include <argv.h> #include <safe.h> #include <clean_env.h> /* clean_env - clean up the environment */ void clean_env(char **preserve_list) { extern char **environ; ARGV *save_list; char *value; char **cpp; char *eq; /* * Preserve or specify selected environment variables. */ #define STRING_AND_LENGTH(x, y) (x), (ssize_t) (y) save_list = argv_alloc(10); for (cpp = preserve_list; *cpp; cpp++) if ((eq = strchr(*cpp, '=')) != 0) argv_addn(save_list, STRING_AND_LENGTH(*cpp, eq - *cpp), STRING_AND_LENGTH(eq + 1, strlen(eq + 1)), (char *) 0); else if ((value = safe_getenv(*cpp)) != 0) argv_add(save_list, *cpp, value, (char *) 0); /* * Truncate the process environment, if available. On some systems * (Ultrix!), environ can be a null pointer. */ if (environ) environ[0] = 0; /* * Restore preserved environment variables. */ for (cpp = save_list->argv; *cpp; cpp += 2) if (setenv(cpp[0], cpp[1], 1)) msg_fatal("setenv(%s, %s): %m", cpp[0], cpp[1]); /* * Cleanup. */ argv_free(save_list); }