[PATCH] (2/5) sane procfs/dcache interaction

 - new helper in fs/proc/base.c - name_to_int(dentry) returns ~0U if name
   doesn't match 0|[1-9][0-9]* or is too large.  Otherwise it returns
   numeric value of name.  proc_pid_lookup() and proc_lookupfd() converted.

diff --git a/fs/proc/base.c b/fs/proc/base.c
index a1b0f655ebf6eddfaf986912658bcc3bdbb88d94..44c1189b6eed3583b297d8cfa4810bff7e808ff1 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -778,34 +778,41 @@ static struct dentry_operations pid_base_dentry_operations =
 };
 
 /* Lookups */
-#define MAX_MULBY10    ((~0U-9)/10)
+
+static unsigned name_to_int(struct dentry *dentry)
+{
+       const char *name = dentry->d_name.name;
+       int len = dentry->d_name.len;
+       unsigned n = 0;
+
+       if (len > 1 && *name == '0')
+               goto out;
+       while (len-- > 0) {
+               unsigned c = *name++ - '0';
+               if (c > 9)
+                       goto out;
+               if (n >= (~0U-9)/10)
+                       goto out;
+               n *= 10;
+               n += c;
+       }
+       return n;
+out:
+       return ~0U;
+}
 
 /* SMP-safe */
 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry)
 {
-       unsigned int fd, c;
        struct task_struct *task = proc_task(dir);
+       unsigned fd = name_to_int(dentry);
        struct file * file;
        struct files_struct * files;
        struct inode *inode;
        struct proc_inode *ei;
-       const char *name;
-       int len;
 
-       fd = 0;
-       len = dentry->d_name.len;
-       name = dentry->d_name.name;
-       if (len > 1 && *name == '0') goto out;
-       while (len-- > 0) {
-               c = *name - '0';
-               name++;
-               if (c > 9)
-                       goto out;
-               if (fd >= MAX_MULBY10)
-                       goto out;
-               fd *= 10;
-               fd += c;
-       }
+       if (fd == ~0U)
+               goto out;
 
        inode = proc_pid_make_inode(dir->i_sb, task, PROC_PID_FD_DIR+fd);
        if (!inode)
@@ -992,17 +999,12 @@ static struct inode_operations proc_self_inode_operations = {
 /* SMP-safe */
 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry)
 {
-       unsigned int pid, c;
        struct task_struct *task;
-       const char *name;
        struct inode *inode;
        struct proc_inode *ei;
-       int len;
+       unsigned pid;
 
-       pid = 0;
-       name = dentry->d_name.name;
-       len = dentry->d_name.len;
-       if (len == 4 && !memcmp(name, "self", 4)) {
+       if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
                inode = new_inode(dir->i_sb);
                if (!inode)
                        return ERR_PTR(-ENOMEM);
@@ -1017,18 +1019,9 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry)
                d_add(dentry, inode);
                return NULL;
        }
-       while (len-- > 0) {
-               c = *name - '0';
-               name++;
-               if (c > 9)
-                       goto out;
-               if (pid >= MAX_MULBY10)
-                       goto out;
-               pid *= 10;
-               pid += c;
-               if (!pid)
-                       goto out;
-       }
+       pid = name_to_int(dentry);
+       if (pid == ~0U)
+               goto out;
 
        read_lock(&tasklist_lock);
        task = find_task_by_pid(pid);