www-cgi/: Centralize environment variable filtering.

[userv-utils.git] / www-cgi / ucgicommon.c

diff --git a/www-cgi/ucgicommon.c b/www-cgi/ucgicommon.c
index 43b7d945aa439ea36ef54ada5bd8534716fd0d00..0facfbb7bb20f39eb0201e7f2974a8869587b5ac 100644 (file)
--- a/www-cgi/ucgicommon.c
+++ b/www-cgi/ucgicommon.c
@@ -22,6 +22,8 @@
 #include <string.h>
 #include <errno.h>
 
+#include <unistd.h>
+
 #include "ucgi.h"
 
 const char *const envok[]= {
@@ -114,3 +116,76 @@ void *xrealloc(void *ptr, size_t sz) {
 void xsetenv(const char *en, const char *ev, int overwrite) {
   if (setenv(en,ev,overwrite)) syserror("setenv");
 }
+
+void filter_environment(unsigned flags, const char *prefix_in,
+                       const char *const *patv,
+                       void (*foundone)(const char *fulln,
+                                        const char *en, const char *ev,
+                                        void *p),
+                       void *p)
+{
+  char *const *ep;
+  const char *const *patp;
+  const char *en, *ev, *pat, *q;
+  char enbuf[MAX_ENVVAR_NAME];
+  size_t n, pn = strlen(prefix_in);
+  int acceptp;
+
+  D( if (debugmode) printf(";; filter_environment...\n"); )
+  for (ep= environ; (en= *ep); ep++) {
+    D( if (debugmode) printf(";;   consider env-var `%s'\n", en); )
+    if (strncmp(en, prefix_in, pn) != 0 || !en[pn]) {
+      D( if (debugmode) printf(";;     doesn't match prefix\n"); )
+      goto next_ev;
+    }
+    for (patp= patv; (pat= *patp); patp++) {
+      q= en + pn;
+      acceptp= 1;
+      if (*pat == '!' && (flags & FILTF_WILDCARD)) {
+       acceptp= 0; pat++;
+      }
+      for (;;) {
+       if (!*pat) {
+         if (*q != '=') {
+           D( if (debugmode)
+                printf(";;     mismatch `%s' (prefix)\n", *patp); )
+           goto next_pat;
+         }
+         D( if (debugmode) printf(";;     matched `%s'\n", *patp); )
+         ev = q + 1;
+         break;
+       } else if (*pat == '*' && (flags & FILTF_WILDCARD)) {
+         q = strchr(q, '=');
+         if (!q) {
+           D( if (debugmode)
+                printf(";;     mismatch `%s' (discard: no `=')\n", *patp); )
+           goto next_ev;
+         }
+         D( if (debugmode)
+              printf(";;     wildcard match for `%s'\n", *patp); )
+         ev = q + 1;
+         break;
+       } else
+         if (*pat++ != *q++) {
+           D( if (debugmode) printf(";;     mismatch `%s'\n", *patp); )
+           goto next_pat;
+         }
+      }
+      if (acceptp) {
+       n= q - en;
+       if (n >= sizeof(enbuf))
+         error("environment variable name too long");
+       memcpy(enbuf, en, n);
+       enbuf[n]= 0;
+       D( if (debugmode)
+            printf(";;     full = `%s'; tail = `%s'; value = `%s'\n",
+                   enbuf, enbuf + pn, ev); )
+       foundone(enbuf, enbuf + pn, ev, p);
+      } D( else if (debugmode)
+            printf(";;     matched negated pattern\n"); )
+      goto next_ev;
+    next_pat:;
+    }
+  next_ev:;
+  }
+}