lib/env: add function to save and restore unwanted variables

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/include/env.h b/include/env.h
index 6cee8e698aa46bfb9ac4a5e46d1311f989514dc4..c2caecbaa0ebcad0c3a44fd669fb259585c8729a 100644 (file)
--- a/include/env.h
+++ b/include/env.h
@@ -4,7 +4,14 @@
 #include "c.h"
 #include "nls.h"
 
+struct ul_env_list;
+
 extern void sanitize_env(void);
+extern void __sanitize_env(struct ul_env_list **org);
+
+extern int env_list_setenv(struct ul_env_list *ls);
+extern void env_list_free(struct ul_env_list *ls);
+
 extern char *safe_getenv(const char *arg);
 
 

diff --git a/lib/env.c b/lib/env.c
index 301b332b473a7f71c79148f7525fe355cee28268..c26a5be3a4ca08579732a1adc3bdb1ff27b6a216 100644 (file)
--- a/lib/env.c
+++ b/lib/env.c
@@ -50,8 +50,73 @@ static char * const noslash[] = {
         (char *) 0
 };
 
-void
-sanitize_env(void)
+
+struct ul_env_list {
+       char *env;
+       struct ul_env_list *next;
+};
+
+/*
+ * Saves @name env.varable to @ls, returns pointer to the new head of the list.
+ */
+static struct ul_env_list *env_list_add(struct ul_env_list *ls0, const char *str)
+{
+       struct ul_env_list *ls;
+       char *p;
+       size_t sz = 0;
+
+       if (!str || !*str)
+               return ls0;
+
+       sz = strlen(str) + 1;
+       p = malloc(sizeof(struct ul_env_list) + sz);
+
+       ls = (struct ul_env_list *) p;
+       p += sizeof(struct ul_env_list);
+       memcpy(p, str, sz);
+       ls->env = p;
+
+       ls->next = ls0;
+       return ls;
+}
+
+/*
+ * Use setenv() for all stuff in @ls.
+ *
+ * It would be possible to use putenv(), but we want to keep @ls free()-able.
+ */
+int env_list_setenv(struct ul_env_list *ls)
+{
+       int rc = 0;
+
+       while (ls && rc == 0) {
+               if (ls->env) {
+                       char *val = strchr(ls->env, '=');
+                       if (!val)
+                               continue;
+                       *val = '\0';
+                       rc = setenv(ls->env, val + 1, 0);
+                       *val = '=';
+               }
+               ls = ls->next;
+       }
+       return rc;
+}
+
+void env_list_free(struct ul_env_list *ls)
+{
+       while (ls) {
+               struct ul_env_list *x = ls;
+               ls = ls->next;
+               free(x);
+       }
+}
+
+/*
+ * Removes unwanted variables from environ[]. If @ls is not NULL than stores
+ * unwnated variables to the list.
+ */
+void __sanitize_env(struct ul_env_list **org)
 {
         char **envp = environ;
         char * const *bad;
@@ -64,6 +129,8 @@ sanitize_env(void)
         for (cur = envp; *cur; cur++) {
                 for (bad = forbid; *bad; bad++) {
                         if (strncmp(*cur, *bad, strlen(*bad)) == 0) {
+                               if (org)
+                                       *org = env_list_add(*org, *cur);
                                 last = remote_entry(envp, cur - envp, last);
                                 cur--;
                                 break;
@@ -77,6 +144,8 @@ sanitize_env(void)
                                 continue;
                         if (!strchr(*cur, '/'))
                                 continue;  /* OK */
+                       if (org)
+                               *org = env_list_add(*org, *cur);
                         last = remote_entry(envp, cur - envp, last);
                         cur--;
                         break;
@@ -84,6 +153,10 @@ sanitize_env(void)
         }
 }
 
+void sanitize_env(void)
+{
+       __sanitize_env(NULL);
+}
 
 char *safe_getenv(const char *arg)
 {
@@ -116,6 +189,7 @@ int main(void)
        char copy[32];
        char *p;
        int retval = EXIT_SUCCESS;
+       struct ul_env_list *removed = NULL;
 
        for (bad = forbid; *bad; bad++) {
                strcpy(copy, *bad);
@@ -124,7 +198,11 @@ int main(void)
                        *p = '\0';
                setenv(copy, copy, 1);
        }
-       sanitize_env();
+
+       /* removed */
+       __sanitize_env(&removed);
+
+       /* check removal */
        for (bad = forbid; *bad; bad++) {
                strcpy(copy, *bad);
                p = strchr(copy, '=');
@@ -136,6 +214,25 @@ int main(void)
                        retval = EXIT_FAILURE;
                }
        }
+
+       /* restore removed */
+       env_list_setenv(removed);
+
+       /* check restore */
+       for (bad = forbid; *bad; bad++) {
+               strcpy(copy, *bad);
+               p = strchr(copy, '=');
+               if (p)
+                       *p = '\0';
+               p = getenv(copy);
+               if (!p) {
+                       warnx("%s was not restored", copy);
+                       retval = EXIT_FAILURE;
+               }
+       }
+
+       env_list_free(removed);
+
        return retval;
 }
 #endif