Initial revision

sysdeps/linux/proclist.c

@@ -0,0 +1,155 @@
+/* $Id$ */
+
+/* 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.  */
+
+#include <config.h>
+#include <glibtop/xmalloc.h>
+#include <glibtop/proclist.h>
+
+#include <sys/stat.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <ctype.h>
+
+static const unsigned long _glibtop_sysdeps_proclist =
+(1 << GLIBTOP_PROCLIST_TOTAL) + (1 << GLIBTOP_PROCLIST_NUMBER) +
+(1 << GLIBTOP_PROCLIST_SIZE);
+
+#define BLOCK_COUNT	256
+#define BLOCK_SIZE	(BLOCK_COUNT * sizeof (unsigned))
+
+/* Fetch list of currently running processes.
+ *
+ * The interface of this function is a little bit different from the others:
+ * buf->flags is only set if the call succeeded, in this case pids_chain,
+ * a list of the pids of all currently running processes is returned,
+ * buf->number is the number of elements of this list and buf->size is
+ * the size of one single element (sizeof (unsigned)). The total size is
+ * stored in buf->total.
+ *
+ * The calling function has to free the memory to which a pointer is returned.
+ *
+ * On error, NULL is returned and buf->flags is zero. */
+
+unsigned *
+glibtop_get_proclist__r (glibtop *server, glibtop_proclist *buf)
+{
+	DIR *proc;
+	struct dirent *entry;
+	char buffer [BUFSIZ];
+	unsigned count, total, pid;
+	unsigned pids [BLOCK_COUNT], *pids_chain = NULL;
+	unsigned pids_size = 0, pids_offset = 0, new_size;
+	struct stat statb;
+	int len, i, ok;
+
+	glibtop_init__r (&server);
+
+	memset (buf, 0, sizeof (glibtop_proclist));
+
+	proc = opendir ("/proc");
+	if (!proc) return NULL;
+
+	/* read every every entry in /proc */
+
+	for (count = total = 0, entry = readdir (proc); entry; entry = readdir (proc)) {
+		ok = 1; len = strlen (entry->d_name);
+
+		/* does it consist entirely of digits? */
+		
+		for (i = 0; i < len; i++)
+			if (!isdigit (entry->d_name [i])) ok = 0;
+		if (!ok) continue;
+
+		/* convert it in a number */
+
+		if (sscanf (entry->d_name, "%u", &pid) != 1) continue;
+
+		/* is it really a directory? */
+
+		sprintf (buffer, "/proc/%d", pid);
+		
+		if (stat (buffer, &statb)) continue;
+
+		if (!S_ISDIR (statb.st_mode)) continue;
+
+		/* Fine. Now we first try to store it in pids. If this buffer is
+		 * full, we copy it to the pids_chain. */
+
+		if (count >= BLOCK_COUNT) {
+			/* The following call to glibtop_realloc will be equivalent to
+			 * glibtop_malloc if pids_chain is NULL. We just calculate the
+			 * new size and copy pids to the beginning of the newly allocated
+			 * block. */
+
+			new_size = pids_size + BLOCK_SIZE;
+
+			pids_chain = glibtop_realloc__r (server, pids_chain, new_size);
+
+			memcpy (pids_chain + pids_offset, pids, BLOCK_SIZE);
+
+			pids_size = new_size;
+
+			pids_offset += BLOCK_COUNT;
+
+			count = 0;
+		}
+
+		/* pids is now big enough to hold at least one single pid. */
+		
+		pids [count++] = pid;
+
+		total++;
+	}
+	
+	closedir (proc);
+
+	/* count is only zero if an error occured (one a running Linux system, we
+	 * only have at least one single process). */
+
+	if (!count) return NULL;
+
+	/* The following call to glibtop_realloc will be equivalent to
+	 * glibtop_malloc if pids_chain is NULL. We just calculate the
+	 * new size and copy pids to the beginning of the newly allocated
+	 * block. */
+	
+	new_size = pids_size + count * sizeof (unsigned);
+	
+	pids_chain = glibtop_realloc__r (server, pids_chain, new_size);
+	
+	memcpy (pids_chain + pids_offset, pids, count * sizeof (unsigned));
+	
+	pids_size = new_size;
+	
+	pids_offset += BLOCK_COUNT;
+
+	/* Since everything is ok now, we can set buf->flags, fill in the remaining fields
+	   and return pids_chain. */
+
+	buf->flags = _glibtop_sysdeps_proclist;
+
+	buf->size = sizeof (unsigned);
+	buf->number = total;
+
+	buf->total = total * sizeof (unsigned);
+
+	return pids_chain;
+}