[darwinbuild-changes] [190] trunk/darwintrace/darwintrace.c

[source_changes at macosforge.org]

Revision: 190
          http://trac.macosforge.org/projects/darwinbuild/changeset/190
Author:   ssen
Date:     2006-10-04 01:56:31 -0700 (Wed, 04 Oct 2006)

Log Message:
-----------
Some projects have excessively clever shell scripts that
try to open specific file descriptors, which ends up stomping
redirecting the darwintrace data. So pick a file descriptor
in the stratosphere and use a reasonable hueristic to see if
it's available, and if so, dup2(2) to it. This isn't perfect,
but allows BerkerleyDB to build with dependencies successfully.

Modified Paths:
--------------
    trunk/darwintrace/darwintrace.c

Modified: trunk/darwintrace/darwintrace.c
===================================================================
--- trunk/darwintrace/darwintrace.c	2005-08-24 02:20:23 UTC (rev 189)
+++ trunk/darwintrace/darwintrace.c	2006-10-04 08:56:31 UTC (rev 190)
@@ -41,11 +41,13 @@
 #include <sys/param.h>
 #include <sys/syscall.h>
 #include <sys/paths.h>
+#include <errno.h>
 
 #define DARWINTRACE_SHOW_PROCESS 0
 #define DARWINTRACE_LOG_FULL_PATH 1
 #define DARWINTRACE_DEBUG_OUTPUT 0
 
+#define START_FD 81
 static int __darwintrace_fd = -2;
 #define BUFFER_SIZE	1024
 #if DARWINTRACE_SHOW_PROCESS
@@ -63,10 +65,21 @@
 	if (__darwintrace_fd == -2) {
 	  char* path = getenv("DARWINTRACE_LOG");
 	  if (path != NULL) {
-		__darwintrace_fd = open(path,
-		O_CREAT | O_WRONLY | O_APPEND,
-		DEFFILEMODE);
-		fcntl(__darwintrace_fd, F_SETFD, 1); /* close-on-exec */
+		int olderrno = errno;
+	    	int fd = open(path,
+			      O_CREAT | O_WRONLY | O_APPEND,
+			      DEFFILEMODE);
+		int newfd;
+		for(newfd = START_FD; newfd < START_FD + 21; newfd++) {
+		  if(-1 == write(newfd, "", 0) && errno == EBADF) {
+		    if(-1 != dup2(fd, newfd))
+		      __darwintrace_fd = newfd;
+		    close(fd);
+		    fcntl(__darwintrace_fd, F_SETFD, 1); /* close-on-exec */
+		    break;
+		  }
+		}
+		errno = olderrno;
 	  }
 	}
 #if DARWINTRACE_SHOW_PROCESS

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