Refactor GETINFO process/descriptor-limit

Previously it duplicated some getrlimit code and content from compat.c;
now it doesn't.

2 files changed, 16 insertions, 24 deletions

diff --git a/src/common/compat.c b/src/common/compat.c
index 7dfc6885e..06eb5839f 100644
--- a/src/common/compat.c
+++ b/src/common/compat.c
@@ -1258,13 +1258,16 @@ tor_socketpair(int family, int type, int protocol, tor_socket_t fd[2])
  * tell Tor it's allowed to use. */
 #define ULIMIT_BUFFER 32 /* keep 32 extra fd's beyond _ConnLimit */
 
-/** Learn the maximum allowed number of file descriptors. (Some systems
- * have a low soft limit.
+/** Learn the maximum allowed number of file descriptors, and tell the system
+ * we want to use up to that number. (Some systems have a low soft limit, and
+ * let us set it higher.)
  *
  * We compute this by finding the largest number that we can use.
  * If we can't find a number greater than or equal to <b>limit</b>,
  * then we fail: return -1.
  *
+ * If <b>limit</b> is 0, then do not adjust the current maximum.
+ *
  * Otherwise, return 0 and store the maximum we found inside <b>max_out</b>.*/
 int
 set_max_file_descriptors(rlim_t limit, int *max_out)
@@ -1297,14 +1300,20 @@ set_max_file_descriptors(rlim_t limit, int *max_out)
   limit = MAX_CONNECTIONS;
 #else /* HAVE_GETRLIMIT */
   struct rlimit rlim;
-  tor_assert(limit > 0);
 
   if (getrlimit(RLIMIT_NOFILE, &rlim) != 0) {
     log_warn(LD_NET, "Could not get maximum number of file descriptors: %s",
              strerror(errno));
     return -1;
   }
-
+  if (limit == 0) {
+    /* If limit == 0, return the maximum value without setting it. */
+    limit = rlim.rlim_max;
+    if (limit > INT_MAX)
+      limit = INT_MAX;
+    *max_out = limit - ULIMIT_BUFFER;
+    return 0;
+  }
   if (rlim.rlim_max < limit) {
     log_warn(LD_CONFIG,"We need %lu file descriptors available, and we're "
              "limited to %lu. Please change your ulimit -n.",
diff --git a/src/or/control.c b/src/or/control.c
index 9465f895a..9fc28bb5c 100644
--- a/src/or/control.c
+++ b/src/or/control.c
@@ -1466,26 +1466,9 @@ getinfo_helper_misc(control_connection_t *conn, const char *question,
       }
     #endif
   } else if (!strcmp(question, "process/descriptor-limit")) {
-    /** platform specifc limits are from the set_max_file_descriptors function
-      * of src/common/compat.c */
-    /* XXXX023 This is duplicated code from compat.c; it should turn into a
-     * function.  */
-    #ifdef HAVE_GETRLIMIT
-      struct rlimit descriptorLimit;
-
-      if (getrlimit(RLIMIT_NOFILE, &descriptorLimit) == 0) {
-        tor_asprintf(answer, U64_FORMAT,
-                     U64_PRINTF_ARG(descriptorLimit.rlim_max));
-      } else {
-        *answer = tor_strdup("-1");
-      }
-    #elif defined(CYGWIN) || defined(__CYGWIN__)
-      *answer = tor_strdup("3200");
-    #elif defined(_WIN32)
-      *answer = tor_strdup("15000");
-    #else
-      *answer = tor_strdup("15000");
-    #endif
+    int max_fds=-1;
+    set_max_file_descriptors(0, &max_fds);
+    tor_asprintf(answer, "%d", max_fds);
   } else if (!strcmp(question, "dir-usage")) {
     *answer = directory_dump_request_log();
   } else if (!strcmp(question, "fingerprint")) {