Improve getting of max. number of open fds.

* configure.ac (AC_CHECK_FUNCS): Add getrlimit.
* src/assuan-pipe-connect.c (MAX_OPEN_FDS): Remove non-used macro.
* src/system.c (MAX_OPEN_FDS): Remove non-used macro.
* src/system-posix.c: Include stdint.h, sys/time.h, sys/resource.h.
(MAX_OPEN_FDS): Remove non-used macro.
(get_max_fds): New.  Taken from gnupg/common/exechelp-posix.c.
(__assuan_spawn): Use it here.
--

This is related to
GnuPG-bug-id: 2071

Changing of get_max_fds from LPGLv3+ to LGPLv2+ approved by me as sole
author or that code.

Signed-off-by: Werner Koch <[email protected]>

4 files changed, 76 insertions, 33 deletions

diff --git a/configure.ac b/configure.ac
index cd1a80d..755a55c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -360,7 +360,8 @@ AM_PATH_GPG_ERROR(1.17,, AC_MSG_ERROR([libgpg-error was not found]))
 #
 # Checks for library functions.
 #
-AC_CHECK_FUNCS([flockfile funlockfile inet_pton stat getaddrinfo])
+AC_CHECK_FUNCS([flockfile funlockfile inet_pton stat getaddrinfo \
+                getrlimit ])
 
 # On some systems (e.g. Solaris) nanosleep requires linking to librl.
 # Given that we use nanosleep only as an optimization over a select
diff --git a/src/assuan-pipe-connect.c b/src/assuan-pipe-connect.c
index edc8dbb..e5d2a38 100644
--- a/src/assuan-pipe-connect.c
+++ b/src/assuan-pipe-connect.c
@@ -65,13 +65,6 @@
 #endif
 
 
-#ifdef _POSIX_OPEN_MAX
-#define MAX_OPEN_FDS _POSIX_OPEN_MAX
-#else
-#define MAX_OPEN_FDS 20
-#endif
-
-
 /* This should be called to make sure that SIGPIPE gets ignored.  */
 static void
 fix_signals (void)
diff --git a/src/system-posix.c b/src/system-posix.c
index 5bdc676..8ca27e6 100644
--- a/src/system-posix.c
+++ b/src/system-posix.c
@@ -24,21 +24,23 @@
 
 #include <stdlib.h>
 #include <errno.h>
+#ifdef HAVE_STDINT_H
+# include <stdint.h>
+#endif
 /* Solaris 8 needs sys/types.h before time.h.  */
 #include <sys/types.h>
 #include <time.h>
 #include <fcntl.h>
 #include <sys/wait.h>
+#ifdef HAVE_GETRLIMIT
+# include <sys/time.h>
+# include <sys/resource.h>
+#endif /*HAVE_GETRLIMIT*/
+
 
 #include "assuan-defs.h"
 #include "debug.h"
 
-#ifdef _POSIX_OPEN_MAX
-#define MAX_OPEN_FDS _POSIX_OPEN_MAX
-#else
-#define MAX_OPEN_FDS 20
-#endif
-
 
 
 
@@ -168,6 +170,61 @@ writen (int fd, const char *buffer, size_t length)
 }
 
 
+/* Return the maximum number of currently allowed open file
+ * descriptors.  */
+static int
+get_max_fds (void)
+{
+  int max_fds = -1;
+
+#ifdef HAVE_GETRLIMIT
+  struct rlimit rl;
+
+# ifdef RLIMIT_NOFILE
+  if (!getrlimit (RLIMIT_NOFILE, &rl))
+    max_fds = rl.rlim_max;
+# endif
+
+# ifdef RLIMIT_OFILE
+  if (max_fds == -1 && !getrlimit (RLIMIT_OFILE, &rl))
+    max_fds = rl.rlim_max;
+
+# endif
+#endif /*HAVE_GETRLIMIT*/
+
+#ifdef _SC_OPEN_MAX
+  if (max_fds == -1)
+    {
+      long int scres = sysconf (_SC_OPEN_MAX);
+      if (scres >= 0)
+        max_fds = scres;
+    }
+#endif
+
+#ifdef _POSIX_OPEN_MAX
+  if (max_fds == -1)
+    max_fds = _POSIX_OPEN_MAX;
+#endif
+
+#ifdef OPEN_MAX
+  if (max_fds == -1)
+    max_fds = OPEN_MAX;
+#endif
+
+  if (max_fds == -1)
+    max_fds = 256;  /* Arbitrary limit.  */
+
+  /* AIX returns INT32_MAX instead of a proper value.  We assume that
+     this is always an error and use a more reasonable limit.  */
+#ifdef INT32_MAX
+  if (max_fds == INT32_MAX)
+    max_fds = 256;
+#endif
+
+  return max_fds;
+}
+
+
 int
 __assuan_spawn (assuan_context_t ctx, pid_t *r_pid, const char *name,
 		const char **argv,
@@ -246,9 +303,7 @@ __assuan_spawn (assuan_context_t ctx, pid_t *r_pid, const char *name,
 
       /* Close all files which will not be duped and are not in the
 	 fd_child_list. */
-      n = sysconf (_SC_OPEN_MAX);
-      if (n < 0)
-	n = MAX_OPEN_FDS;
+      n = get_max_fds ();
       for (i = 0; i < n; i++)
 	{
 	  if (i == STDIN_FILENO || i == STDOUT_FILENO || i == STDERR_FILENO)
diff --git a/src/system.c b/src/system.c
index 1fca056..ddb99fb 100644
--- a/src/system.c
+++ b/src/system.c
@@ -36,12 +36,6 @@
 #include "assuan-defs.h"
 #include "debug.h"
 
-#ifdef _POSIX_OPEN_MAX
-#define MAX_OPEN_FDS _POSIX_OPEN_MAX
-#else
-#define MAX_OPEN_FDS 20
-#endif
-
 #define DEBUG_SYSIO 0
 
 
@@ -66,11 +60,11 @@ _assuan_calloc (assuan_context_t ctx, size_t cnt, size_t elsize)
 {
   void *ptr;
   size_t nbytes;
-    
+
   nbytes = cnt * elsize;
 
   /* Check for overflow.  */
-  if (elsize && nbytes / elsize != cnt) 
+  if (elsize && nbytes / elsize != cnt)
     {
       gpg_err_set_errno (ENOMEM);
       return NULL;
@@ -111,7 +105,7 @@ _assuan_system_hooks_copy (assuan_system_hooks_t dst,
   /* Reset the defaults.  */
   if (dst != &_assuan_system_hooks)
     memcpy (dst, &_assuan_system_hooks, sizeof (*dst));
-      
+
   dst->version = ASSUAN_SYSTEM_HOOKS_VERSION;
   if (src->version >= 1)
     {
@@ -164,7 +158,7 @@ _assuan_pipe (assuan_context_t ctx, assuan_fd_t fd[2], int inherit_idx)
   if (err)
     return TRACE_SYSRES (err);
 
-  return TRACE_SUC2 ("read=0x%x, write=0x%x", fd[0], fd[1]); 
+  return TRACE_SUC2 ("read=0x%x, write=0x%x", fd[0], fd[1]);
 }
 
 
@@ -257,7 +251,7 @@ _assuan_recvmsg (assuan_context_t ctx, assuan_fd_t fd, assuan_msghdr_t msg,
 		      cmptr->cmsg_len - (((char *)data) - ((char *)cmptr)),
 		      cmptr->cmsg_level, cmptr->cmsg_type, *(int *)data);
 	}
-    }    
+    }
   return TRACE_SYSRES (res);
 #else
   return (ctx->system.recvmsg) (ctx, fd, msg, flags);
@@ -280,7 +274,7 @@ _assuan_sendmsg (assuan_context_t ctx, assuan_fd_t fd, assuan_msghdr_t msg,
     TRACE_LOG2 ("msg->iov[0] = { iov_base=%p, iov_len=%i }",
 		msg->msg_iov[0].iov_base, msg->msg_iov[0].iov_len);
     TRACE_LOGBUF (msg->msg_iov[0].iov_base, msg->msg_iov[0].iov_len);
-    
+
     cmptr = CMSG_FIRSTHDR (msg);
     if (cmptr)
       {
@@ -358,7 +352,7 @@ _assuan_spawn (assuan_context_t ctx, pid_t *r_pid, const char *name,
 
 /* FIXME: Add some sort of waitpid function that covers GPGME and
    gpg-agent's use of assuan.  */
-pid_t 
+pid_t
 _assuan_waitpid (assuan_context_t ctx, pid_t pid, int action,
 		 int *status, int options)
 {
@@ -384,7 +378,7 @@ _assuan_socketpair (assuan_context_t ctx, int namespace, int style,
   TRACE_BEG4 (ctx, ASSUAN_LOG_SYSIO, "_assuan_socketpair", ctx,
 	      "namespace=%i,style=%i,protocol=%i,filedes=%p",
 	      namespace, style, protocol, filedes);
-  
+
   res = (ctx->system.socketpair) (ctx, namespace, style, protocol, filedes);
   if (res == 0)
     TRACE_LOG2 ("filedes = { 0x%x, 0x%x }", filedes[0], filedes[1]);
@@ -401,7 +395,7 @@ _assuan_socket (assuan_context_t ctx, int namespace, int style, int protocol)
   TRACE_BEG3 (ctx, ASSUAN_LOG_SYSIO, "_assuan_socket", ctx,
 	      "namespace=%i,style=%i,protocol=%i",
 	      namespace, style, protocol);
-  
+
   res = (ctx->system.socket) (ctx, namespace, style, protocol);
   return TRACE_SYSRES (res);
 }
@@ -413,7 +407,7 @@ _assuan_connect (assuan_context_t ctx, int sock, struct sockaddr *addr, socklen_
   int res;
   TRACE_BEG3 (ctx, ASSUAN_LOG_SYSIO, "_assuan_connect", ctx,
 	      "socket=%i,addr=%p,length=%i", sock, addr, length);
-  
+
   res = (ctx->system.connect) (ctx, sock, addr, length);
   return TRACE_SYSRES (res);
 }