1 files changed, 122 insertions, 28 deletions

diff --git a/ps.c b/ps.c
index 207cdaa02..b0933ab51 100644
--- a/ps.c
+++ b/ps.c
@@ -1,34 +1,47 @@
 /* vi: set sw=4 ts=4: */
 /*
- * Mini ps implementation for busybox
+ * Mini ps implementation(s) for busybox
  *
+ * Copyright (C) 1999 by Lineo, inc.  Written by Erik Andersen
+ * <andersen@lineo.com>, <andersee@debian.org>
  *
- * Copyright (C) 1999 by Lineo, inc.
- * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * This contains _two_ implementations of ps for Linux.  One uses the
+ * traditional /proc virtual filesystem, and the other use the devps kernel
+ * driver (written by Erik Andersen to avoid using /proc thereby saving 100k+).
  *
- * This program 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
- * General Public License for more details.
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program 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 General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA 02111-1307 USA
  *
  */
 
 #include "internal.h"
+#include <stdio.h>
 #include <unistd.h>
 #include <dirent.h>
-#include <stdio.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <ctype.h>
 
+#if ! defined BB_FEATURE_USE_DEVPS_N_DEVMTAB
+
+/* The following is the first ps implementation --
+ * the one using the /proc virtual filesystem.
+ */
+
 #if ! defined BB_FEATURE_USE_PROCFS
 #error Sorry, I depend on the /proc filesystem right now.
 #endif
@@ -105,16 +118,12 @@ extern int ps_main(int argc, char **argv)
         char groupName[10] = "";
         int i, c;
 
-        if (argc > 1 && **(argv + 1) == '-') {
-                usage
-                        ("ps\n\nReport process status\n\nThis version of ps accepts no options.\n");
-        }
+        if (argc > 1 && **(argv + 1) == '-')
+                usage ("ps\n\nReport process status\n\nThis version of ps accepts no options.\n");
 
         dir = opendir("/proc");
-        if (!dir) {
-                perror("Can't open /proc");
-                exit(FALSE);
-        }
+        if (!dir)
+                fatalError("Can't open /proc");
 
         fprintf(stdout, "%5s  %-8s %-3s %5s %s\n", "PID", "Uid", "Gid",
                         "State", "Command");
@@ -131,9 +140,9 @@ extern int ps_main(int argc, char **argv)
 
                 /* Make some adjustments as needed */
                 my_getpwuid(uidName, p.ruid);
-                my_getgrgid(groupName, p.rgid);
                 if (*uidName == '\0')
                         sprintf(uidName, "%d", p.ruid);
+                my_getgrgid(groupName, p.rgid);
                 if (*groupName == '\0')
                         sprintf(groupName, "%d", p.rgid);
 
@@ -141,10 +150,8 @@ extern int ps_main(int argc, char **argv)
                                 p.state);
                 sprintf(path, "/proc/%s/cmdline", entry->d_name);
                 file = fopen(path, "r");
-                if (file == NULL) {
-                        perror(path);
-                        exit(FALSE);
-                }
+                if (file == NULL)
+                        fatalError("Can't open %s: %s\n", path, strerror(errno));
                 i = 0;
                 while (((c = getc(file)) != EOF) && (i < 53)) {
                         i++;
@@ -159,3 +166,90 @@ extern int ps_main(int argc, char **argv)
         closedir(dir);
         exit(TRUE);
 }
+
+
+#else /* BB_FEATURE_USE_DEVPS_N_DEVMTAB */
+
+
+/* The following is the second ps implementation --
+ * this one uses the nifty new devps kernel device.
+ */
+
+#include <sys/ioctl.h>
+#include <linux/devps.h>
+
+
+extern int ps_main(int argc, char **argv)
+{
+        char device[] = "/dev/ps";
+        int i, fd;
+        pid_t num_pids;
+        pid_t* pid_array = NULL;
+        struct pid_info info;
+        char uidName[10] = "";
+        char groupName[10] = "";
+
+        if (argc > 1 && **(argv + 1) == '-') 
+                usage("ps-devps\n\nReport process status\n\nThis version of ps accepts no options.\n\n");
+
+        /* open device */ 
+        fd = open(device, O_RDONLY);
+        if (fd < 0) 
+                fatalError( "open failed for `%s': %s\n", device, strerror (errno));
+
+        /* Find out how many processes there are */
+        if (ioctl (fd, DEVPS_GET_NUM_PIDS, &num_pids)<0) 
+                fatalError( "\nDEVPS_GET_PID_LIST: %s\n", strerror (errno));
+        
+        /* Allocate some memory -- grab a few extras just in case 
+         * some new processes start up while we wait. The kernel will
+         * just ignore any extras if we give it too many, and will trunc.
+         * the list if we give it too few.  */
+        pid_array = (pid_t*) calloc( num_pids+10, sizeof(pid_t));
+        pid_array[0] = num_pids+10;
+
+        /* Now grab the pid list */
+        if (ioctl (fd, DEVPS_GET_PID_LIST, pid_array)<0) 
+                fatalError("\nDEVPS_GET_PID_LIST: %s\n", strerror (errno));
+
+        /* Print up a ps listing */
+        fprintf(stdout, "%5s  %-8s %-3s %5s %s\n", "PID", "Uid", "Gid",
+                        "State", "Command");
+
+        for (i=1; i<pid_array[0] ; i++) {
+                uidName[0] = '\0';
+                groupName[0] = '\0';
+            info.pid = pid_array[i];
+
+            if (ioctl (fd, DEVPS_GET_PID_INFO, &info)<0)
+                        fatalError("\nDEVPS_GET_PID_INFO: %s\n", strerror (errno));
+            
+                /* Make some adjustments as needed */
+                my_getpwuid(uidName, info.euid);
+                if (*uidName == '\0')
+                        sprintf(uidName, "%ld", info.euid);
+                my_getgrgid(groupName, info.egid);
+                if (*groupName == '\0')
+                        sprintf(groupName, "%ld", info.egid);
+
+                fprintf(stdout, "%5d %-8s %-8s %c ", info.pid, uidName, groupName, info.state);
+
+                if (strlen(info.command_line) > 1)
+                        fprintf(stdout, "%s\n", info.command_line);
+                else
+                        fprintf(stdout, "[%s]\n", info.name);
+
+        }
+
+        /* Free memory */
+        free( pid_array);
+
+        /* close device */
+        if (close (fd) != 0) 
+                fatalError("close failed for `%s': %s\n", device, strerror (errno));
+ 
+        exit (0);
+}
+
+#endif /* BB_FEATURE_USE_DEVPS_N_DEVMTAB */
+