1 files changed, 91 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/common/pcprofile.c b/libc/sysdeps/linux/common/pcprofile.c
new file mode 100644
index 000000000..d5a9601b4
--- /dev/null
+++ b/libc/sysdeps/linux/common/pcprofile.c
@@ -0,0 +1,91 @@
+/* Profile PC and write result to FIFO.
+   Copyright (C) 1999, 2000 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1999.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#define _GNU_SOURCE
+#include <features.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+/* Nonzero if we are actually doing something.  */
+static int active;
+
+/* The file descriptor of the FIFO.  */
+static int fd;
+
+
+static void __attribute__ ((constructor))
+install (void)
+{
+    /* See whether the environment variable `PCPROFILE_OUTPUT' is defined.
+       If yes, it should name a FIFO.  We open it and mark ourself as active.  */
+    const char *outfile = getenv ("PCPROFILE_OUTPUT");
+
+    if (outfile != NULL && *outfile != '\0')
+    {
+	fd = open (outfile, O_RDWR | O_CREAT, 0666);
+
+	if (fd != -1)
+	{
+	    uint32_t word;
+
+	    active = 1;
+
+	    /* Write a magic word which tells the reader about the byte
+	       order and the size of the following entries.  */
+	    word = 0xdeb00000 | sizeof (void *);
+	    if (TEMP_FAILURE_RETRY (write (fd, &word, 4)) != 4)
+	    {
+		/* If even this fails we shouldn't try further.  */
+		close (fd);
+		fd = -1;
+		active = 0;
+	    }
+	}
+    }
+}
+
+
+static void __attribute__ ((destructor))
+uninstall (void)
+{
+    if (active)
+	close (fd);
+}
+
+
+void __cyg_profile_func_enter (void *this_fn, void *call_site)
+{
+    void *buf[2];
+
+    if (! active)
+	return;
+
+    /* Now write out the current position and that of the caller.  We do
+       this now, and don't cache the because we want real-time output.  */
+    buf[0] = this_fn;
+    buf[1] = call_site;
+
+    write (fd, buf, sizeof buf);
+}
+/* We don't handle entry and exit differently here.  */
+strong_alias (__cyg_profile_func_enter, __cyg_profile_func_exit)