summaryrefslogtreecommitdiff
path: root/libc/sysdeps/linux/common/pcprofile.c
diff options
context:
space:
mode:
Diffstat (limited to 'libc/sysdeps/linux/common/pcprofile.c')
-rw-r--r--libc/sysdeps/linux/common/pcprofile.c91
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)