- add llist_free_one() and llist_free() to libbb; Add a bit of documentation.

- change llist_add_to_end as proposed by vodz in http://busybox.net/lists/busybox/2005-September/016411.html
- remove unneeded includes, add short boilerplate and copyright to llist.c
- move COMM_LEN from find_pid_by_name to libbb.h and use it in procps_status_t
- add reverse_pidlist() to find_pid_by_name. Will be needed for pidof.


git-svn-id: svn://busybox.net/trunk/busybox@11785 69ca8d6d-28ef-0310-b511-8ec308f3f277

3 files changed, 73 insertions, 32 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 484f4e07b..ee5fb8475 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -131,6 +131,7 @@ extern int get_console_fd(void);
 extern struct mntent *find_mount_point(const char *name, const char *table);
 extern void erase_mtab(const char * name);
 extern long *find_pid_by_name( const char* pidName);
+extern long *pidlist_reverse(long *pidList);
 extern char *find_block_device(char *path);
 extern char *bb_get_line_from_file(FILE *file);
 extern char *bb_get_chomped_line_from_file(FILE *file);
@@ -431,6 +432,15 @@ extern ssize_t bb_xread(int fd, void *buf, size_t count);
 extern void bb_xread_all(int fd, void *buf, size_t count);
 extern unsigned char bb_xread_char(int fd);
 
+#ifndef COMM_LEN
+/*#include <sched.h> *//* Task command name length */
+#ifdef TASK_COMM_LEN
+#define COMM_LEN TASK_COMM_LEN
+#else
+#define COMM_LEN 16 /* synchronize with size of comm in struct task_struct
+                                                                  in /usr/include/linux/sched.h */
+#endif
+#endif
 typedef struct {
         int pid;
         char user[9];
@@ -446,7 +456,7 @@ typedef struct {
 
         /* basename of executable file in call to exec(2),
                 size from kernel headers */
-        char short_cmd[16];
+        char short_cmd[COMM_LEN];
 } procps_status_t;
 
 extern procps_status_t * procps_scan(int save_user_arg0);
@@ -460,6 +470,8 @@ typedef struct llist_s {
 } llist_t;
 extern llist_t *llist_add_to(llist_t *old_head, char *new_item);
 extern llist_t *llist_add_to_end(llist_t *list_head, char *data);
+extern llist_t *llist_free_one(llist_t *elm);
+extern void llist_free(llist_t *elm);
 
 extern void print_login_issue(const char *issue_file, const char *tty);
 extern void print_login_prompt(void);
diff --git a/libbb/find_pid_by_name.c b/libbb/find_pid_by_name.c
index 570e7bd93..966595ddb 100644
--- a/libbb/find_pid_by_name.c
+++ b/libbb/find_pid_by_name.c
@@ -4,19 +4,7 @@
  *
  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.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 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
+ * Licensed under the GPL v2, see the file LICENSE in this tarball.
  */
 
 #include <stdio.h>
@@ -25,10 +13,6 @@
 #include <stdlib.h>
 #include "libbb.h"
 
-#define COMM_LEN 16 /* synchronize with size of comm in struct task_struct
-                                           in /usr/include/linux/sched.h */
-
-
 /* find_pid_by_name()
  *
  *  Modified by Vladimir Oleynik for use with libbb/procps.c
@@ -37,6 +21,7 @@
  *  the proc filesystem.
  *
  *  Returns a list of all matching PIDs
+ *  It is the caller's duty to free the returned pidlist.
  */
 extern long* find_pid_by_name( const char* pidName)
 {
@@ -45,7 +30,7 @@ extern long* find_pid_by_name( const char* pidName)
         procps_status_t * p;
 
         pidList = xmalloc(sizeof(long));
-        while ((p = procps_scan(0)) != 0) 
+        while ((p = procps_scan(0)) != 0)
         {
                 if (strncmp(p->short_cmd, pidName, COMM_LEN-1) == 0) {
                         pidList=xrealloc( pidList, sizeof(long) * (i+2));
@@ -57,6 +42,22 @@ extern long* find_pid_by_name( const char* pidName)
         return pidList;
 }
 
+extern long *pidlist_reverse(long *pidList)
+{
+        int i=0;
+        while (pidList[i] > 0 && i++);
+        if ( i-- > 0) {
+                long k;
+                int j;
+                for (j = 0; i > j; i--, j++) {
+                        k = pidList[i];
+                        pidList[i] = pidList[j];
+                        pidList[j] = k;
+                }
+        }
+        return pidList;
+}
+
 /* END CODE */
 /*
 Local Variables:
diff --git a/libbb/llist.c b/libbb/llist.c
index cb87176c5..ce7daddee 100644
--- a/libbb/llist.c
+++ b/libbb/llist.c
@@ -1,9 +1,18 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * linked list helper functions.
+ *
+ * Copyright (C) 2003 Glenn McGrath
+ * Copyright (C) 2005 Vladimir Oleynik
+ * Copyright (C) 2005 Bernhard Fischer
+ *
+ * Licensed under the GPL v2, see the file LICENSE in this tarball.
+ */
 #include <stdlib.h>
-#include <string.h>
-#include "unarchive.h"
 #include "libbb.h"
 
 #ifdef L_llist_add_to
+/* Add data to the start of the linked list.  */
 extern llist_t *llist_add_to(llist_t *old_head, char *new_item)
 {
         llist_t *new_head;
@@ -17,27 +26,46 @@ extern llist_t *llist_add_to(llist_t *old_head, char *new_item)
 #endif
 
 #ifdef L_llist_add_to_end
+/* Add data to the end of the linked list.  */
 extern llist_t *llist_add_to_end(llist_t *list_head, char *data)
 {
-        llist_t *new_item, *tmp, *prev;
+        llist_t *new_item;
 
         new_item = xmalloc(sizeof(llist_t));
         new_item->data = data;
         new_item->link = NULL;
 
-        prev = NULL;
-        tmp = list_head;
-        while (tmp) {
-                prev = tmp;
-                tmp = tmp->link;
-        }
-        if (prev) {
-                prev->link = new_item;
-        } else {
+        if (list_head == NULL) {
                 list_head = new_item;
+        } else {
+                llist_t *tail = list_head;
+                while (tail->link)
+                        tail = tail->link;
+                tail->link = new_item;
         }
+        return list_head;
+}
+#endif
 
-        return (list_head);
+#ifdef L_llist_free_one
+/* Free the current list element and advance to the next entry in the list.
+ * Returns a pointer to the next element.  */
+extern llist_t *llist_free_one(llist_t *elm)
+{
+        llist_t *next = elm ? elm->link : NULL;
+#if ENABLE_DMALLOC /* avoid warnings from dmalloc's error-free-null option */
+        if (elm)
+#endif
+                free(elm);
+        elm = next;
+        return elm;
 }
 #endif
 
+#ifdef L_llist_free
+/* Recursively free all elements in the linked list.  */
+extern void llist_free(llist_t *elm)
+{
+        while ((elm = llist_free_one(elm)));
+}
+#endif