prefork: Move garbage handling back cgi-fcgi-interp

[chiark-utils.git] / cprogs / cgi-fcgi-interp.c

diff --git a/cprogs/cgi-fcgi-interp.c b/cprogs/cgi-fcgi-interp.c
index 1c160e29c35bd6a2f4b8e6adb263c6013e2d958b..7ed562590fb558b931fb4f5ebf5afab67671713b 100644 (file)
--- a/cprogs/cgi-fcgi-interp.c
+++ b/cprogs/cgi-fcgi-interp.c
@@ -135,6 +135,9 @@ static const char *stage2;
 
 const char our_name[] = "cgi-fcgi-interp";
 
+static int numservers=4, debugmode;
+static int check_interval=300;
+
 const struct cmdinfo cmdinfos[]= {
   { "help",   0, .call=of_help                                         },
   { 0, 'g',   1,                    .sassignto= &ident                 },
@@ -165,6 +168,104 @@ static void prep_stage2(void) {
   if (r) diee("set %s (to announce to stage2)", STAGE2_VAR);
 }
 
+#ifdef st_mtime
+
+static bool stab_isnewer(const struct stat *a, const struct stat *b) {
+  if (debugmode)
+    fprintf(stderr,"stab_isnewer mtim %lu.%06lu %lu.06%lu\n",
+           (unsigned long)a->st_mtim.tv_sec,
+           (unsigned long)a->st_mtim.tv_nsec,
+           (unsigned long)b->st_mtim.tv_sec,
+           (unsigned long)b->st_mtim.tv_nsec);
+  return timespeccmp(&a->st_mtim, &b->st_mtim, >);
+}
+
+static void stab_mtimenow(struct stat *out) {
+  int r = clock_gettime(CLOCK_REALTIME, &out->st_mtim);
+  if (r) diee("(stage2) clock_gettime");
+  if (debugmode)
+    fprintf(stderr,"stab_mtimenow mtim %lu.%06lu\n",
+           (unsigned long)out->st_mtim.tv_sec,
+           (unsigned long)out->st_mtim.tv_nsec);
+}
+
+#else /* !defined(st_mtime) */
+
+static bool stab_isnewer(const struct stat *a, const struct stat *b) {
+  if (debugmode)
+    fprintf(stderr,"stab_isnewer mtime %lu %lu\n",
+           (unsigned long)a->st_mtime,
+           (unsigned long)b->st_mtime);
+  return a->st_mtime > b->st_mtime;
+}
+
+static void stab_mtimenow(struct stat *out) {
+  out->st_mtime = time(NULL);
+  if (out->st_mtime == (time_t)-1) diee("(stage2) time()");
+  if (debugmode)
+    fprintf(stderr,"stab_mtimenow mtime %lu\n",
+           (unsigned long)out->st_mtime);
+}
+
+#endif /* !defined(st_mtime) */
+
+static bool check_garbage_vs(const struct stat *started) {
+  struct stat script_stab;
+  int r;
+
+  r = lstat(script, &script_stab);
+  if (r) diee("lstat script (%s)",script);
+
+  if (stab_isnewer(&script_stab, started))
+    return 1;
+
+  if (S_ISLNK(script_stab.st_mode)) {
+    r = stat(script, &script_stab);
+    if (r) diee("stat script (%s0",script);
+
+    if (stab_isnewer(&script_stab, started))
+      return 1;
+  }
+
+  return 0;
+}
+
+static bool check_garbage(void) {
+  struct stat sock_stab;
+  int r;
+
+  r = lstat(socket_path, &sock_stab);
+  if (r) {
+    if ((errno == ENOENT))
+      return 0; /* well, no garbage then */
+    diee("stat socket (%s)",socket_path);
+  }
+
+  return check_garbage_vs(&sock_stab);
+}
+
+static void tidy_garbage(void) {
+  /* We lock l<ident> and re-check.  The effect of this is that each
+   * stale socket is removed only once.  So unless multiple updates to
+   * the script happen rapidly, we can't be racing with the cgi-fcgi
+   * (which is recreating the socket */
+  int lockfd = -1;
+  int r;
+
+  lockfd = acquire_lock();
+
+  if (check_garbage()) {
+    r = unlink(socket_path);
+    if (r) {
+      if (!(errno == ENOENT))
+       diee("remove out-of-date socket (%s)", socket_path);
+    }
+  }
+
+  r = close(lockfd);
+  if (r) diee("close lock (%s)", lock_path);
+}
+
 /* stage2 predeclarations */
 static void record_baseline_time(void);
 static void become_pgrp(void);