proc: convert to kstrto*()/kstrto*_from_user()

Convert from manual allocation/copy_from_user/...  to kstrto*() family
which were designed for exactly that.

One case can not be converted to kstrto*_from_user() to make code even
more simpler because of whitespace stripping, oh well...

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 60c71b10eaee8857dceeb3eda1dea0a351235bd5..b25eee4cead5398b69889c95c29480ba9862c397 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1230,10 +1230,9 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
                                   size_t count, loff_t *ppos)
 {
        struct inode * inode = file_inode(file);
-       char *page, *tmp;
-       ssize_t length;
        uid_t loginuid;
        kuid_t kloginuid;
+       int rv;
 
        rcu_read_lock();
        if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
@@ -1242,46 +1241,28 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
        }
        rcu_read_unlock();
 
-       if (count >= PAGE_SIZE)
-               count = PAGE_SIZE - 1;
-
        if (*ppos != 0) {
                /* No partial writes. */
                return -EINVAL;
        }
-       page = (char*)__get_free_page(GFP_TEMPORARY);
-       if (!page)
-               return -ENOMEM;
-       length = -EFAULT;
-       if (copy_from_user(page, buf, count))
-               goto out_free_page;
 
-       page[count] = '\0';
-       loginuid = simple_strtoul(page, &tmp, 10);
-       if (tmp == page) {
-               length = -EINVAL;
-               goto out_free_page;
-
-       }
+       rv = kstrtou32_from_user(buf, count, 10, &loginuid);
+       if (rv < 0)
+               return rv;
 
        /* is userspace tring to explicitly UNSET the loginuid? */
        if (loginuid == AUDIT_UID_UNSET) {
                kloginuid = INVALID_UID;
        } else {
                kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
-               if (!uid_valid(kloginuid)) {
-                       length = -EINVAL;
-                       goto out_free_page;
-               }
+               if (!uid_valid(kloginuid))
+                       return -EINVAL;
        }
 
-       length = audit_set_loginuid(kloginuid);
-       if (likely(length == 0))
-               length = count;
-
-out_free_page:
-       free_page((unsigned long) page);
-       return length;
+       rv = audit_set_loginuid(kloginuid);
+       if (rv < 0)
+               return rv;
+       return count;
 }
 
 static const struct file_operations proc_loginuid_operations = {
@@ -1335,8 +1316,9 @@ static ssize_t proc_fault_inject_write(struct file * file,
                        const char __user * buf, size_t count, loff_t *ppos)
 {
        struct task_struct *task;
-       char buffer[PROC_NUMBUF], *end;
+       char buffer[PROC_NUMBUF];
        int make_it_fail;
+       int rv;
 
        if (!capable(CAP_SYS_RESOURCE))
                return -EPERM;
@@ -1345,9 +1327,9 @@ static ssize_t proc_fault_inject_write(struct file * file,
                count = sizeof(buffer) - 1;
        if (copy_from_user(buffer, buf, count))
                return -EFAULT;
-       make_it_fail = simple_strtol(strstrip(buffer), &end, 0);
-       if (*end)
-               return -EINVAL;
+       rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
+       if (rv < 0)
+               return rv;
        if (make_it_fail < 0 || make_it_fail > 1)
                return -EINVAL;
 
@@ -2488,32 +2470,20 @@ static ssize_t proc_coredump_filter_write(struct file *file,
 {
        struct task_struct *task;
        struct mm_struct *mm;
-       char buffer[PROC_NUMBUF], *end;
        unsigned int val;
        int ret;
        int i;
        unsigned long mask;
 
-       ret = -EFAULT;
-       memset(buffer, 0, sizeof(buffer));
-       if (count > sizeof(buffer) - 1)
-               count = sizeof(buffer) - 1;
-       if (copy_from_user(buffer, buf, count))
-               goto out_no_task;
-
-       ret = -EINVAL;
-       val = (unsigned int)simple_strtoul(buffer, &end, 0);
-       if (*end == '\n')
-               end++;
-       if (end - buffer == 0)
-               goto out_no_task;
+       ret = kstrtouint_from_user(buf, count, 0, &val);
+       if (ret < 0)
+               return ret;
 
        ret = -ESRCH;
        task = get_proc_task(file_inode(file));
        if (!task)
                goto out_no_task;
 
-       ret = end - buffer;
        mm = get_task_mm(task);
        if (!mm)
                goto out_no_mm;
@@ -2529,7 +2499,9 @@ static ssize_t proc_coredump_filter_write(struct file *file,
  out_no_mm:
        put_task_struct(task);
  out_no_task:
-       return ret;
+       if (ret < 0)
+               return ret;
+       return count;
 }
 
 static const struct file_operations proc_coredump_filter_operations = {