load_env: parse the environment variables in-place

The environment variable parsing can be easily done in-place to
avoid allocating two large buffers on stack.
Fixes: #18

diff --git a/src/env.c b/src/env.c
index 5fa2e2c3928fa2df38c61bdd15581388326a9a55..0b44ded97390886ae5a3988ba883e3f392c725d7 100644 (file)
--- a/src/env.c
+++ b/src/env.c
@@ -181,8 +181,7 @@ int load_env(char *envstr, FILE * f) {
        long filepos;
        int fileline;
        enum env_state state;
-       char name[MAX_ENVSTR], val[MAX_ENVSTR];
-       char quotechar, *c, *str;
+       char quotechar, *c, *str, *val;
 
        filepos = ftell(f);
        fileline = LineNumber;
@@ -192,10 +191,7 @@ int load_env(char *envstr, FILE * f) {
 
        Debug(DPARS, ("load_env, read <%s>\n", envstr));
 
-       memset(name, 0, sizeof name);
-       memset(val, 0, sizeof val);
-
-       str = name;
+       str = envstr;
        state = NAMEI;
        quotechar = '\0';
        c = envstr;
@@ -239,8 +235,9 @@ int load_env(char *envstr, FILE * f) {
                case EQ1:
                        if (*c == '=') {
                                state++;
-                               str = val;
                                quotechar = '\0';
+                               *str++ = *c;
+                               val = str;
                        }
                        else {
                                if (!isspace((unsigned char) *c))
@@ -263,29 +260,19 @@ int load_env(char *envstr, FILE * f) {
        }
        if (state != FINI && state != EQ2 && !(state == VALUE && !quotechar)) {
                Debug(DPARS, ("load_env, not an env var, state = %d\n", state));
-                       if (fseek(f, filepos, 0)) {
-                return ERR;
-           }
+               if (fseek(f, filepos, 0)) {
+                       return ERR;
+               }
                Set_LineNum(fileline);
                return (FALSE);
        }
+       *str = '\0';
        if (state == VALUE) {
                /* End of unquoted value: trim trailing whitespace */
-               c = val + strlen(val);
-               while (c > val && isspace((unsigned char) c[-1]))
-                       *(--c) = '\0';
+               while (str > val && isspace((unsigned char)str[-1]))
+                       *(--str) = '\0';
        }
-
-       /* 2 fields from parser; looks like an env setting */
-
-       /*
-        * This can't overflow because get_string() limited the size of the
-        * name and val fields.  Still, it doesn't hurt to be careful...
-        */
-       if (!glue_strings(envstr, MAX_ENVSTR, name, val, '='))
-               return (FALSE);
-       Debug(DPARS, ("load_env, <%s> <%s> -> <%s>\n", name, val, envstr));
-               return (TRUE);
+       return TRUE;
 }
 
 char *env_get(const char *name, char **envp) {