New file.

1998-06-07  Martin Baulig  <martin@home-of-linux.org>

	* sysdeps/linux/glibtop_machine.h: New file.

	* sysdeps/linux/*.c: Performance optimizations. We now use
	`open' and `read' instead of `fopen' and `fscanf'.

13 files changed, 451 insertions, 194 deletions

diff --git a/sysdeps/linux/cpu.c b/sysdeps/linux/cpu.c
index 058f3586..6dc68c6a 100644
--- a/sysdeps/linux/cpu.c
+++ b/sysdeps/linux/cpu.c
@@ -20,6 +20,7 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <config.h>
+#include <glibtop/error.h>
 #include <glibtop/cpu.h>
 
 static const unsigned long _glibtop_sysdeps_cpu =
@@ -29,10 +30,13 @@ static const unsigned long _glibtop_sysdeps_cpu =
 
 /* Provides information about cpu usage. */
 
+#define FILENAME	"/proc/stat"
+
 void
 glibtop_get_cpu_s (glibtop *server, glibtop_cpu *buf)
 {
-	FILE *f;
+	char buffer [BUFSIZ];
+	int fd = 0, ret;
 
 	glibtop_init_r (&server, 0, 0);
 
@@ -40,15 +44,33 @@ glibtop_get_cpu_s (glibtop *server, glibtop_cpu *buf)
 
 	buf->flags = _glibtop_sysdeps_cpu;
 
-	f = fopen ("/proc/stat", "r");
-	if (!f) return;
+#ifdef GLIBTOP_CACHE_OPEN
+	fd = server->machine.fd_stat;
+#endif
+	if (fd == 0) {
+		fd = open (FILENAME, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 FILENAME, strerror (errno));
+	} else {
+		lseek (fd, 0, SEEK_SET);
+	}
+
+	ret = read (fd, buffer, BUFSIZ);
+	if (ret == -1)
+		glibtop_error_r (server, "read (%s): %s",
+				 FILENAME, strerror (errno));
 
-	fscanf (f, "cpu %lu %lu %lu %lu\n",
+	sscanf (buffer, "cpu %lu %lu %lu %lu\n",
 		&buf->user, &buf->nice, &buf->sys, &buf->idle);
 
 	buf->total = buf->user + buf->nice + buf->sys + buf->idle;
 
 	buf->frequency = 100;
   
-	fclose (f);
+#ifdef GLIBTOP_CACHE_OPEN
+	server->machine.fd_stat = fd;
+#else
+	close (fd);
+#endif
 }
diff --git a/sysdeps/linux/glibtop_machine.h b/sysdeps/linux/glibtop_machine.h
new file mode 100644
index 00000000..600d562c
--- /dev/null
+++ b/sysdeps/linux/glibtop_machine.h
@@ -0,0 +1,43 @@
+/* $Id$ */
+
+/* Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
+   This file is part of the Gnome Top Library.
+   Contributed by Martin Baulig <martin@home-of-linux.org>, April 1998.
+
+   The Gnome Top Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The Gnome Top 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#ifndef __GLIBTOP_MACHINE_H__
+#define __GLIBTOP_MACHINE_H__
+
+#include <unistd.h>
+#include <fcntl.h>
+
+__BEGIN_DECLS
+
+typedef struct _glibtop_machine		glibtop_machine;
+
+struct _glibtop_machine
+{
+	pid_t	last_pid;
+	int	no_update;
+	int	fd_stat, fd_meminfo, fd_loadavg;
+	char	proc_stat [BUFSIZ], proc_statm [BUFSIZ];
+	char	proc_status [BUFSIZ];
+};
+
+__END_DECLS
+
+#endif
diff --git a/sysdeps/linux/loadavg.c b/sysdeps/linux/loadavg.c
index fbfa310f..96565610 100644
--- a/sysdeps/linux/loadavg.c
+++ b/sysdeps/linux/loadavg.c
@@ -20,17 +20,21 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <config.h>
+#include <glibtop/error.h>
 #include <glibtop/loadavg.h>
 
 static const unsigned long _glibtop_sysdeps_loadavg =
 (1 << GLIBTOP_LOADAVG_LOADAVG);
 
+#define FILENAME	"/proc/loadavg"
+
 /* Provides load load averange. */
 
 void
 glibtop_get_loadavg_s (glibtop *server, glibtop_loadavg *buf)
 {
-	FILE *f;
+	char buffer [BUFSIZ];
+	int fd = 0, ret;
 
 	glibtop_init_r (&server, 0, 0);
 
@@ -38,11 +42,29 @@ glibtop_get_loadavg_s (glibtop *server, glibtop_loadavg *buf)
 
 	buf->flags = _glibtop_sysdeps_loadavg;
 
-	f = fopen ("/proc/loadavg", "r");
-	if (!f) return;
+#ifdef GLIBTOP_CACHE_OPEN
+	fd = server->machine.fd_loadavg;
+#endif
+	if (fd == 0) {
+		fd = open (FILENAME, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 FILENAME, strerror (errno));
+	} else {
+		lseek (fd, 0, SEEK_SET);
+	}
+
+	ret = read (fd, buffer, BUFSIZ);
+	if (ret == -1)
+		glibtop_error_r (server, "read (%s): %s",
+				 FILENAME, strerror (errno));
 
-	fscanf (f, "%lf %lf %lf\n",
+	sscanf (buffer, "%lf %lf %lf\n",
 		&buf->loadavg [0], &buf->loadavg [1], &buf->loadavg [2]);
   
-	fclose (f);
+#ifdef GLIBTOP_CACHE_OPEN
+	server->machine.fd_loadavg = fd;
+#else
+	close (fd);
+#endif
 }
diff --git a/sysdeps/linux/mem.c b/sysdeps/linux/mem.c
index 937a6c81..41b54323 100644
--- a/sysdeps/linux/mem.c
+++ b/sysdeps/linux/mem.c
@@ -20,6 +20,7 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <config.h>
+#include <glibtop/error.h>
 #include <glibtop/mem.h>
 
 static const unsigned long _glibtop_sysdeps_mem =
@@ -28,12 +29,15 @@ static const unsigned long _glibtop_sysdeps_mem =
 (1 << GLIBTOP_MEM_BUFFER) + (1 << GLIBTOP_MEM_CACHED) +
 (1 << GLIBTOP_MEM_USER);
 
+#define FILENAME	"/proc/meminfo"
+
 /* Provides information about memory usage. */
 
 void
 glibtop_get_mem_s (glibtop *server, glibtop_mem *buf)
 {
-	FILE *f;
+	char buffer [BUFSIZ];
+	int fd = 0, ret;
 
 	glibtop_init_r (&server, 0, 0);
 
@@ -41,13 +45,32 @@ glibtop_get_mem_s (glibtop *server, glibtop_mem *buf)
 
 	buf->flags = _glibtop_sysdeps_mem;
 
-	f = fopen ("/proc/meminfo", "r");
-	if (!f) return;
+#ifdef GLIBTOP_CACHE_OPEN
+	fd = server->machine.fd_meminfo;
+#endif
+	if (fd == 0) {
+		fd = open (FILENAME, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 FILENAME, strerror (errno));
+	} else {
+		lseek (fd, 0, SEEK_SET);
+	}
+
+	ret = read (fd, buffer, BUFSIZ);
+	if (ret == -1)
+		glibtop_error_r (server, "read (%s): %s",
+				 FILENAME, strerror (errno));
 
-	fscanf (f, "%*[^\n]\nMem: %lu %lu %lu %lu %lu %lu\n",
-		&buf->total, &buf->used, &buf->free, &buf->shared, &buf->buffer, &buf->cached);
+	sscanf (buffer, "%*[^\n]\nMem: %lu %lu %lu %lu %lu %lu\n",
+		&buf->total, &buf->used, &buf->free, &buf->shared,
+		&buf->buffer, &buf->cached);
 
 	buf->user = buf->total - buf->free - buf->shared - buf->buffer;
 
-	fclose (f);
+#ifdef GLIBTOP_CACHE_OPEN
+	server->machine.fd_meminfo = fd;
+#else
+	close (fd);
+#endif
 }
diff --git a/sysdeps/linux/prockernel.c b/sysdeps/linux/prockernel.c
index 13e56b62..e9fc8eb9 100644
--- a/sysdeps/linux/prockernel.c
+++ b/sysdeps/linux/prockernel.c
@@ -20,6 +20,7 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <glibtop.h>
+#include <glibtop/error.h>
 #include <glibtop/prockernel.h>
 
 static const unsigned long _glibtop_sysdeps_proc_kernel =
@@ -33,9 +34,8 @@ static const unsigned long _glibtop_sysdeps_proc_kernel =
 void
 glibtop_get_proc_kernel_s (glibtop *server, glibtop_proc_kernel *buf, pid_t pid)
 {
-	char input [BUFSIZ], *tmp;
-	int nread;
-	FILE *f;
+	char buffer [BUFSIZ], input [BUFSIZ], *tmp;
+	int fd = 0, nread;
 	
 	glibtop_init_r (&server, 0, 0);
 
@@ -47,24 +47,41 @@ glibtop_get_proc_kernel_s (glibtop *server, glibtop_proc_kernel *buf, pid_t pid)
 		return;
 	}
 
-	sprintf (input, "/proc/%d/stat", pid);
+	if (pid != server->machine.last_pid) {
+		server->machine.last_pid = pid;
+		server->machine.no_update = 0;
+	}
 
-	f = fopen (input, "r");
-	if (!f) return;
-	
-	nread = fread (input, 1, BUFSIZ, f);
-	
-	if (nread < 0) {
-		fclose (f);
-		return;
+	if (!server->machine.no_update) {
+		server->machine.proc_status [0] = 0;
+		server->machine.proc_statm [0] = 0;
+		server->machine.proc_stat [0] = 0;
 	}
-	
-	input [nread] = 0;
-	
+
+	if (server->machine.proc_stat [0]) {
+		strcpy (buffer, server->machine.proc_stat);
+	} else {
+		sprintf (input, "/proc/%d/stat", pid);
+		
+		fd = open (input, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 input, strerror (errno));
+		
+		nread = read (fd, buffer, BUFSIZ);
+		if (nread == -1)
+			glibtop_error_r (server, "read (%s): %s",
+					 input, strerror (errno));
+		
+		buffer [nread] = 0;
+		strcpy (server->machine.proc_stat, buffer);
+		close (fd);
+	}
+		
 	/* This is from guile-utils/gtop/proc/readproc.c */
 	
 	/* split into "PID (cmd" and "<rest>" */
-	tmp = strrchr (input, ')');
+	tmp = strrchr (buffer, ')');
 	*tmp = '\0';		/* replace trailing ')' with NUL */
 	/* parse these two strings separately, skipping the leading "(". */
 
@@ -75,8 +92,6 @@ glibtop_get_proc_kernel_s (glibtop *server, glibtop_proc_kernel *buf, pid_t pid)
 	       &buf->k_flags, &buf->min_flt, &buf->cmin_flt,
 	       &buf->maj_flt, &buf->cmaj_flt, &buf->kstk_esp,
 	       &buf->kstk_eip, &buf->wchan);
-	
-	fclose (f);
 
 	buf->flags = _glibtop_sysdeps_proc_kernel;
 }
diff --git a/sysdeps/linux/procmem.c b/sysdeps/linux/procmem.c
index 22e0c128..fb03466e 100644
--- a/sysdeps/linux/procmem.c
+++ b/sysdeps/linux/procmem.c
@@ -20,6 +20,7 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <glibtop.h>
+#include <glibtop/error.h>
 #include <glibtop/procmem.h>
 
 static const unsigned long _glibtop_sysdeps_proc_mem =
@@ -32,9 +33,8 @@ static const unsigned long _glibtop_sysdeps_proc_mem =
 void
 glibtop_get_proc_mem_s (glibtop *server, glibtop_proc_mem *buf, pid_t pid)
 {
-	char input [BUFSIZ], *tmp;
-	int nread;
-	FILE *f;
+	char buffer [BUFSIZ], input [BUFSIZ], *tmp;
+	int fd = 0, nread;
 	
 	glibtop_init_r (&server, 0, 0);
 
@@ -46,24 +46,41 @@ glibtop_get_proc_mem_s (glibtop *server, glibtop_proc_mem *buf, pid_t pid)
 		return;
 	}
 
-	sprintf (input, "/proc/%d/stat", pid);
+	if (pid != server->machine.last_pid) {
+		server->machine.last_pid = pid;
+		server->machine.no_update = 0;
+	}
 
-	f = fopen (input, "r");
-	if (!f) return;
-	
-	nread = fread (input, 1, BUFSIZ, f);
-	
-	if (nread < 0) {
-		fclose (f);
-		return;
+	if (!server->machine.no_update) {
+		server->machine.proc_status [0] = 0;
+		server->machine.proc_statm [0] = 0;
+		server->machine.proc_stat [0] = 0;
+	}
+
+	if (server->machine.proc_stat [0]) {
+		strcpy (buffer, server->machine.proc_stat);
+	} else {
+		sprintf (input, "/proc/%d/stat", pid);
+		
+		fd = open (input, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 input, strerror (errno));
+		
+		nread = read (fd, buffer, BUFSIZ);
+		if (nread == -1)
+			glibtop_error_r (server, "read (%s): %s",
+					 input, strerror (errno));
+		
+		buffer [nread] = 0;
+		strcpy (server->machine.proc_stat, buffer);
+		close (fd);
 	}
-	
-	input [nread] = 0;
 	
 	/* This is from guile-utils/gtop/proc/readproc.c */
 	
 	/* split into "PID (cmd" and "<rest>" */
-	tmp = strrchr (input, ')');
+	tmp = strrchr (buffer, ')');
 	*tmp = '\0';		/* replace trailing ')' with NUL */
 	/* parse these two strings separately, skipping the leading "(". */
 	sscanf(tmp + 2,		/* skip space after ')' too */
@@ -71,26 +88,28 @@ glibtop_get_proc_mem_s (glibtop *server, glibtop_proc_mem *buf, pid_t pid)
 	       "%*d %*d %*d %*d %*d %*d %*u %*u %*d %lu "
 	       "%lu %lu", &buf->vsize, &buf->rss, &buf->rss_rlim);
 	
-	fclose (f);
-
-	sprintf (input, "/proc/%d/statm", pid);
-
-	f = fopen (input, "r");
-	if (!f) return;
-
-	nread = fread (input, 1, BUFSIZ, f);
-
-	if (nread < 0) {
-		fclose (f);
-		return;
+	if (server->machine.proc_statm [0]) {
+		strcpy (buffer, server->machine.proc_statm);
+	} else {
+		sprintf (input, "/proc/%d/statm", pid);
+		
+		fd = open (input, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 input, strerror (errno));
+		
+		nread = read (fd, buffer, BUFSIZ);
+		if (nread == -1)
+			glibtop_error_r (server, "read (%s): %s",
+					 input, strerror (errno));
+
+		buffer [nread] = 0;
+		strcpy (server->machine.proc_statm, buffer);
+		close (fd);
 	}
-
-	input [nread] = 0;
-
-	sscanf (input, "%ld %ld %ld",
+		
+	sscanf (buffer, "%ld %ld %ld",
 		&buf->size, &buf->resident, &buf->share);
 
-	fclose (f);
-
 	buf->flags = _glibtop_sysdeps_proc_mem;
 }
diff --git a/sysdeps/linux/procsegment.c b/sysdeps/linux/procsegment.c
index d5ce5652..1ecefa2a 100644
--- a/sysdeps/linux/procsegment.c
+++ b/sysdeps/linux/procsegment.c
@@ -20,6 +20,7 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <config.h>
+#include <glibtop/error.h>
 #include <glibtop/procsegment.h>
 
 static const unsigned long _glibtop_sysdeps_proc_segment =
@@ -32,11 +33,10 @@ static const unsigned long _glibtop_sysdeps_proc_segment =
 
 void
 glibtop_get_proc_segment_s (glibtop *server, glibtop_proc_segment *buf,
-			     pid_t pid)
+			    pid_t pid)
 {
-	char input [BUFSIZ], *tmp;
-	int nread;
-	FILE *f;
+	char buffer [BUFSIZ], input [BUFSIZ], *tmp;
+	int fd = 0, nread;
 	
 	glibtop_init_r (&server, 0, 0);
 
@@ -48,24 +48,41 @@ glibtop_get_proc_segment_s (glibtop *server, glibtop_proc_segment *buf,
 		return;
 	}
 
-	sprintf (input, "/proc/%d/stat", pid);
+	if (pid != server->machine.last_pid) {
+		server->machine.last_pid = pid;
+		server->machine.no_update = 0;
+	}
 
-	f = fopen (input, "r");
-	if (!f) return;
-	
-	nread = fread (input, 1, BUFSIZ, f);
-	
-	if (nread < 0) {
-		fclose (f);
-		return;
+	if (!server->machine.no_update) {
+		server->machine.proc_status [0] = 0;
+		server->machine.proc_statm [0] = 0;
+		server->machine.proc_stat [0] = 0;
 	}
-	
-	input [nread] = 0;
-	
+
+	if (server->machine.proc_stat [0]) {
+		strcpy (buffer, server->machine.proc_stat);
+	} else {
+		sprintf (input, "/proc/%d/stat", pid);
+		
+		fd = open (input, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 input, strerror (errno));
+		
+		nread = read (fd, buffer, BUFSIZ);
+		if (nread == -1)
+			glibtop_error_r (server, "read (%s): %s",
+					 input, strerror (errno));
+		
+		buffer [nread] = 0;
+		strcpy (server->machine.proc_stat, buffer);
+		close (fd);
+	}
+
 	/* This is from guile-utils/gtop/proc/readproc.c */
 	
 	/* split into "PID (cmd" and "<rest>" */
-	tmp = strrchr (input, ')');
+	tmp = strrchr (buffer, ')');
 	*tmp = '\0';		/* replace trailing ')' with NUL */
 	/* parse these two strings separately, skipping the leading "(". */
 	sscanf(tmp + 2,		/* skip space after ')' too */
@@ -74,26 +91,28 @@ glibtop_get_proc_segment_s (glibtop *server, glibtop_proc_segment *buf,
 	       "%*u %*u %lu %lu %lu", &buf->start_code,
 	       &buf->end_code, &buf->start_stack);
 	
-	fclose (f);
-
-	sprintf (input, "/proc/%d/statm", pid);
-
-	f = fopen (input, "r");
-	if (!f) return;
-
-	nread = fread (input, 1, BUFSIZ, f);
-
-	if (nread < 0) {
-		fclose (f);
-		return;
+	if (server->machine.proc_statm [0]) {
+		strcpy (buffer, server->machine.proc_statm);
+	} else {
+		sprintf (input, "/proc/%d/statm", pid);
+		
+		fd = open (input, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 input, strerror (errno));
+		
+		nread = read (fd, buffer, BUFSIZ);
+		if (nread == -1)
+			glibtop_error_r (server, "read (%s): %s",
+					 input, strerror (errno));
+		
+		buffer [nread] = 0;
+		strcpy (server->machine.proc_statm, buffer);
+		close (fd);
 	}
 
-	input [nread] = 0;
-
-	sscanf (input, "%*d %*d %*d %ld %ld %ld %ld",
+	sscanf (buffer, "%*d %*d %*d %ld %ld %ld %ld",
 		&buf->trs, &buf->lrs, &buf->drs, &buf->dt);
 
-	fclose (f);
-
 	buf->flags = _glibtop_sysdeps_proc_segment;
 }
diff --git a/sysdeps/linux/procsignal.c b/sysdeps/linux/procsignal.c
index 6cd51788..7ae451a1 100644
--- a/sysdeps/linux/procsignal.c
+++ b/sysdeps/linux/procsignal.c
@@ -20,6 +20,7 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <glibtop.h>
+#include <glibtop/error.h>
 #include <glibtop/procsignal.h>
 
 static const unsigned long _glibtop_sysdeps_proc_signal =
@@ -31,9 +32,8 @@ static const unsigned long _glibtop_sysdeps_proc_signal =
 void
 glibtop_get_proc_signal_s (glibtop *server, glibtop_proc_signal *buf, pid_t pid)
 {
-	char input [BUFSIZ], *tmp;
-	int nread;
-	FILE *f;
+	char buffer [BUFSIZ], input [BUFSIZ], *tmp;
+	int fd = 0, nread;
 	
 	glibtop_init_r (&server, 0, 0);
 
@@ -45,24 +45,41 @@ glibtop_get_proc_signal_s (glibtop *server, glibtop_proc_signal *buf, pid_t pid)
 		return;
 	}
 
-	sprintf (input, "/proc/%d/stat", pid);
+	if (pid != server->machine.last_pid) {
+		server->machine.last_pid = pid;
+		server->machine.no_update = 0;
+	}
 
-	f = fopen (input, "r");
-	if (!f) return;
-	
-	nread = fread (input, 1, BUFSIZ, f);
-	
-	if (nread < 0) {
-		fclose (f);
-		return;
+	if (!server->machine.no_update) {
+		server->machine.proc_status [0] = 0;
+		server->machine.proc_statm [0] = 0;
+		server->machine.proc_stat [0] = 0;
 	}
-	
-	input [nread] = 0;
-	
+
+	if (server->machine.proc_stat [0]) {
+		strcpy (buffer, server->machine.proc_stat);
+	} else {
+		sprintf (input, "/proc/%d/stat", pid);
+		
+		fd = open (input, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 input, strerror (errno));
+		
+		nread = read (fd, buffer, BUFSIZ);
+		if (nread == -1)
+			glibtop_error_r (server, "read (%s): %s",
+					 input, strerror (errno));
+		
+		buffer [nread] = 0;
+		strcpy (server->machine.proc_stat, buffer);
+		close (fd);
+	}
+
 	/* This is from guile-utils/gtop/proc/readproc.c */
 	
 	/* split into "PID (cmd" and "<rest>" */
-	tmp = strrchr (input, ')');
+	tmp = strrchr (buffer, ')');
 	*tmp = '\0';		/* replace trailing ')' with NUL */
 	/* parse these two strings separately, skipping the leading "(". */
 	sscanf(tmp + 2,		/* skip space after ')' too */
@@ -72,7 +89,5 @@ glibtop_get_proc_signal_s (glibtop *server, glibtop_proc_signal *buf, pid_t pid)
 	       &buf->signal, &buf->blocked, &buf->sigignore,
 	       &buf->sigcatch);
 	
-	fclose (f);
-
 	buf->flags = _glibtop_sysdeps_proc_signal;
 }
diff --git a/sysdeps/linux/procstate.c b/sysdeps/linux/procstate.c
index 48d83209..4a504961 100644
--- a/sysdeps/linux/procstate.c
+++ b/sysdeps/linux/procstate.c
@@ -20,6 +20,7 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <glibtop.h>
+#include <glibtop/error.h>
 #include <glibtop/procstate.h>
 
 #include <sys/stat.h>
@@ -33,10 +34,9 @@ static const unsigned long _glibtop_sysdeps_proc_state =
 void
 glibtop_get_proc_state_s (glibtop *server, glibtop_proc_state *buf, pid_t pid)
 {
-	char input [BUFSIZ], *tmp;
+	char buffer [BUFSIZ], input [BUFSIZ], *tmp;
 	struct stat statb;
-	int nread;
-	FILE *f;
+	int fd, nread;
 	
 	glibtop_init_r (&server, 0, 0);
 
@@ -48,6 +48,12 @@ glibtop_get_proc_state_s (glibtop *server, glibtop_proc_state *buf, pid_t pid)
 		return;
 	}
 
+	server->machine.last_pid = pid;
+	server->machine.no_update = 0;
+	server->machine.proc_status [0] = 0;
+	server->machine.proc_statm [0] = 0;
+	server->machine.proc_stat [0] = 0;
+
 	sprintf (input, "/proc/%d/stat", pid);
 
 	/* IMPORTANT NOTICE: For security reasons it is extremely important
@@ -61,28 +67,34 @@ glibtop_get_proc_state_s (glibtop *server, glibtop_proc_state *buf, pid_t pid)
 	
 	buf->uid = statb.st_uid;
 	buf->gid = statb.st_gid;
+
+	fd = open (input, O_RDONLY);
+	if (fd == -1)
+		glibtop_error_r (server, "open (%s): %s",
+				 input, strerror (errno));
+
+	nread = read (fd, buffer, BUFSIZ);
+	if (nread == -1)
+		glibtop_error_r (server, "read (%s): %s",
+				 input, strerror (errno));
 	
-	f = fopen (input, "r");
-	if (!f) return;
-	
-	nread = fread (input, 1, BUFSIZ, f);
-	
-	if (nread < 0) {
-		fclose (f);
-		return;
-	}
-	
-	input [nread] = 0;
+	buffer [nread] = 0;
+
+	server->machine.no_update = 1;
+	server->machine.last_pid = pid;
+	strcpy (server->machine.proc_stat, buffer);
 	
 	/* This is from guile-utils/gtop/proc/readproc.c */
 	
 	/* split into "PID (cmd" and "<rest>" */
-	tmp = strrchr (input, ')');
+	tmp = strrchr (buffer, ')');
 	*tmp = '\0';		/* replace trailing ')' with NUL */
 	/* parse these two strings separately, skipping the leading "(". */
 	memset (buf->cmd, 0, sizeof (buf->cmd));
-	sscanf (input, "%d (%39c", &pid, buf->cmd);
+	sscanf (buffer, "%d (%39c", &pid, buf->cmd);
 	sscanf(tmp + 2, "%c", &buf->state); /* skip space after ')' too */
 
+	close (fd);
+
 	buf->flags = _glibtop_sysdeps_proc_state;
 }
diff --git a/sysdeps/linux/proctime.c b/sysdeps/linux/proctime.c
index 7393215a..949deb2a 100644
--- a/sysdeps/linux/proctime.c
+++ b/sysdeps/linux/proctime.c
@@ -20,6 +20,7 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <glibtop.h>
+#include <glibtop/error.h>
 #include <glibtop/proctime.h>
 
 static const unsigned long _glibtop_sysdeps_proc_time =
@@ -33,9 +34,8 @@ static const unsigned long _glibtop_sysdeps_proc_time =
 void
 glibtop_get_proc_time_s (glibtop *server, glibtop_proc_time *buf, pid_t pid)
 {
-	char input [BUFSIZ], *tmp;
-	int nread;
-	FILE *f;
+	char buffer [BUFSIZ], input [BUFSIZ], *tmp;
+	int fd = 0, nread;
 	
 	glibtop_init_r (&server, 0, 0);
 
@@ -47,24 +47,41 @@ glibtop_get_proc_time_s (glibtop *server, glibtop_proc_time *buf, pid_t pid)
 		return;
 	}
 
-	sprintf (input, "/proc/%d/stat", pid);
+	if (pid != server->machine.last_pid) {
+		server->machine.last_pid = pid;
+		server->machine.no_update = 0;
+	}
 
-	f = fopen (input, "r");
-	if (!f) return;
-	
-	nread = fread (input, 1, BUFSIZ, f);
-	
-	if (nread < 0) {
-		fclose (f);
-		return;
+	if (!server->machine.no_update) {
+		server->machine.proc_status [0] = 0;
+		server->machine.proc_statm [0] = 0;
+		server->machine.proc_stat [0] = 0;
 	}
-	
-	input [nread] = 0;
-	
+
+	if (server->machine.proc_stat [0]) {
+		strcpy (buffer, server->machine.proc_stat);
+	} else {
+		sprintf (input, "/proc/%d/stat", pid);
+		
+		fd = open (input, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 input, strerror (errno));
+		
+		nread = read (fd, buffer, BUFSIZ);
+		if (nread == -1)
+			glibtop_error_r (server, "read (%s): %s",
+					 input, strerror (errno));
+		
+		buffer [nread] = 0;
+		strcpy (server->machine.proc_stat, buffer);
+		close (fd);
+	}
+
 	/* This is from guile-utils/gtop/proc/readproc.c */
 	
 	/* split into "PID (cmd" and "<rest>" */
-	tmp = strrchr (input, ')');
+	tmp = strrchr (buffer, ')');
 	*tmp = '\0';		/* replace trailing ')' with NUL */
 	/* parse these two strings separately, skipping the leading "(". */
 	sscanf(tmp + 2,		/* skip space after ')' too */
@@ -73,7 +90,5 @@ glibtop_get_proc_time_s (glibtop *server, glibtop_proc_time *buf, pid_t pid)
 	       &buf->utime, &buf->stime, &buf->cutime, &buf->cstime,
 	       &buf->timeout, &buf->it_real_value, &buf->start_time);
 	
-	fclose (f);
-
 	buf->flags = _glibtop_sysdeps_proc_time;
 }
diff --git a/sysdeps/linux/procuid.c b/sysdeps/linux/procuid.c
index 783589a1..0c25bddd 100644
--- a/sysdeps/linux/procuid.c
+++ b/sysdeps/linux/procuid.c
@@ -20,6 +20,7 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <glibtop.h>
+#include <glibtop/error.h>
 #include <glibtop/procuid.h>
 
 static const unsigned long _glibtop_sysdeps_proc_uid =
@@ -37,9 +38,8 @@ static const unsigned long _glibtop_sysdeps_proc_uid =
 void
 glibtop_get_proc_uid_s (glibtop *server, glibtop_proc_uid *buf, pid_t pid)
 {
-	char input [BUFSIZ], *tmp;
-	int nread;
-	FILE *f;
+	char buffer [BUFSIZ], input [BUFSIZ], *tmp;
+	int fd = 0, nread;
 	
 	glibtop_init_r (&server, 0, 0);
 
@@ -51,23 +51,40 @@ glibtop_get_proc_uid_s (glibtop *server, glibtop_proc_uid *buf, pid_t pid)
 		return;
 	}
 
-	sprintf (input, "/proc/%d/status", pid);
-	
-	f = fopen (input, "r");
-	if (!f) return;
+	if (pid != server->machine.last_pid) {
+		server->machine.last_pid = pid;
+		server->machine.no_update = 0;
+	}
 
-	nread = fread (input, 1, BUFSIZ, f);
-	
-	if (nread < 0) {
-		fclose (f);
-		return;
+	if (!server->machine.no_update) {
+		server->machine.proc_status [0] = 0;
+		server->machine.proc_statm [0] = 0;
+		server->machine.proc_stat [0] = 0;
 	}
+
+	if (server->machine.proc_status [0]) {
+		strcpy (buffer, server->machine.proc_status);
+	} else {
+		sprintf (input, "/proc/%d/status", pid);
+		
+		fd = open (input, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 input, strerror (errno));
+
+		nread = read (fd, buffer, BUFSIZ);
+		if (nread == -1)
+			glibtop_error_r (server, "read (%s): %s",
+					 input, strerror (errno));
 	
-	input [nread] = 0;
+		buffer [nread] = 0;
+		strcpy (server->machine.proc_status, buffer);
+		close (fd);
+	}
 
 	/* Search substring 'Pid:' */
 
-	tmp = strstr (input, "Pid:");
+	tmp = strstr (buffer, "Pid:");
 
 	if (tmp == NULL) return;
 
@@ -75,26 +92,30 @@ glibtop_get_proc_uid_s (glibtop *server, glibtop_proc_uid *buf, pid_t pid)
 		"Gid: %u %u %*u %*u\n", &buf->pid, &buf->ppid,
 		&buf->uid, &buf->euid, &buf->gid, &buf->egid);
 	
-	fclose (f);
-
-	sprintf (input, "/proc/%d/stat", pid);
-
-	f = fopen (input, "r");
-	if (!f) return;
-	
-	nread = fread (input, 1, BUFSIZ, f);
-	
-	if (nread < 0) {
-		fclose (f);
-		return;
+	if (server->machine.proc_stat [0]) {
+		strcpy (buffer, server->machine.proc_stat);
+	} else {
+		sprintf (input, "/proc/%d/stat", pid);
+		
+		fd = open (input, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 input, strerror (errno));
+		
+		nread = read (fd, buffer, BUFSIZ);
+		if (nread == -1)
+			glibtop_error_r (server, "read (%s): %s",
+					 input, strerror (errno));
+		
+		buffer [nread] = 0;
+		strcpy (server->machine.proc_stat, buffer);
+		close (fd);
 	}
 	
-	input [nread] = 0;
-	
 	/* This is from guile-utils/gtop/proc/readproc.c */
 	
 	/* split into "PID (cmd" and "<rest>" */
-	tmp = strrchr (input, ')');
+	tmp = strrchr (buffer, ')');
 	*tmp = '\0';		/* replace trailing ')' with NUL */
 	/* parse these two strings separately, skipping the leading "(". */
 	sscanf(tmp + 2,		/* skip space after ')' too */
@@ -116,7 +137,5 @@ glibtop_get_proc_uid_s (glibtop *server, glibtop_proc_uid *buf, pid_t pid)
 		/* when tty wasn't full devno */
 		buf->tty = 4*0x100 + buf->tty;
 	
-	fclose (f);
-
 	buf->flags = _glibtop_sysdeps_proc_uid;
 }
diff --git a/sysdeps/linux/swap.c b/sysdeps/linux/swap.c
index 73ee5000..fd8b29f7 100644
--- a/sysdeps/linux/swap.c
+++ b/sysdeps/linux/swap.c
@@ -20,18 +20,22 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <config.h>
+#include <glibtop/error.h>
 #include <glibtop/swap.h>
 
 static unsigned long _glibtop_sysdeps_swap =
 (1 << GLIBTOP_SWAP_TOTAL) + (1 << GLIBTOP_SWAP_USED) +
 (1 << GLIBTOP_SWAP_FREE);
 
+#define FILENAME	"/proc/meminfo"
+
 /* Provides information about swap usage. */
 
 void
 glibtop_get_swap_s (glibtop *server, glibtop_swap *buf)
 {
-	FILE *f;
+	char buffer [BUFSIZ];
+	int fd = 0, ret;
 
 	glibtop_init_r (&server, 0, 0);
 
@@ -39,11 +43,29 @@ glibtop_get_swap_s (glibtop *server, glibtop_swap *buf)
 
 	buf->flags = _glibtop_sysdeps_swap;
 
-	f = fopen ("/proc/meminfo", "r");
-	if (!f) return;
+#ifdef GLIBTOP_CACHE_OPEN
+	fd = server->machine.fd_meminfo;
+#endif
+	if (fd == 0) {
+		fd = open (FILENAME, O_RDONLY);
+		if (fd == -1)
+			glibtop_error_r (server, "open (%s): %s",
+					 FILENAME, strerror (errno));
+	} else {
+		lseek (fd, 0, SEEK_SET);
+	}
+
+	ret = read (fd, buffer, BUFSIZ);
+	if (ret == -1)
+		glibtop_error_r (server, "read (%s): %s",
+				 FILENAME, strerror (errno));
 
-	fscanf (f, "%*[^\n]\n%*[^\n]\nSwap: %lu %lu %lu\n",
+	sscanf (buffer, "%*[^\n]\n%*[^\n]\nSwap: %lu %lu %lu\n",
 		&buf->total, &buf->used, &buf->free);
 
-	fclose (f);
+#ifdef GLIBTOP_CACHE_OPEN
+	server->machine.fd_meminfo = fd;
+#else
+	close (fd);
+#endif
 }
diff --git a/sysdeps/linux/uptime.c b/sysdeps/linux/uptime.c
index 26dd355b..17b263cb 100644
--- a/sysdeps/linux/uptime.c
+++ b/sysdeps/linux/uptime.c
@@ -20,17 +20,21 @@
    Boston, MA 02111-1307, USA.  */
 
 #include <config.h>
+#include <glibtop/error.h>
 #include <glibtop/uptime.h>
 
 static unsigned long _glibtop_sysdeps_uptime =
 (1 << GLIBTOP_UPTIME_UPTIME) + (1 << GLIBTOP_UPTIME_IDLETIME);
 
+#define FILENAME	"/proc/uptime"
+
 /* Provides uptime and idle time. */
 
 void
 glibtop_get_uptime_s (glibtop *server, glibtop_uptime *buf)
 {
-	FILE *f;
+	int fd, ret;
+	char buffer [BUFSIZ];
 
 	glibtop_init_r (&server, 0, 0);
 
@@ -38,10 +42,17 @@ glibtop_get_uptime_s (glibtop *server, glibtop_uptime *buf)
 
 	buf->flags = _glibtop_sysdeps_uptime;
 
-	f = fopen ("/proc/uptime", "r");
-	if (!f) return;
+	fd = open (FILENAME, O_RDONLY);
+	if (fd == -1)
+		glibtop_error_r (server, "open (%s): %s",
+				 FILENAME, strerror (errno));
+
+	ret = read (fd, buffer, BUFSIZ);
+	if (ret == -1)
+		glibtop_error_r (server, "read (%s): %s",
+				 FILENAME, strerror (errno));
 
-	fscanf (f, "%lf %lf\n", &buf->uptime, &buf->idletime);
+	sscanf (buffer, "%lf %lf\n", &buf->uptime, &buf->idletime);
 
-	fclose (f);
+	close (fd);
 }