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-rw-r--r--fs/read_write.c89
1 files changed, 67 insertions, 22 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 03430008704e..122a3846d9e1 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -41,8 +41,19 @@ static inline int unsigned_offsets(struct file *file)
return file->f_mode & FMODE_UNSIGNED_OFFSET;
}
-static loff_t lseek_execute(struct file *file, struct inode *inode,
- loff_t offset, loff_t maxsize)
+/**
+ * vfs_setpos - update the file offset for lseek
+ * @file: file structure in question
+ * @offset: file offset to seek to
+ * @maxsize: maximum file size
+ *
+ * This is a low-level filesystem helper for updating the file offset to
+ * the value specified by @offset if the given offset is valid and it is
+ * not equal to the current file offset.
+ *
+ * Return the specified offset on success and -EINVAL on invalid offset.
+ */
+loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
{
if (offset < 0 && !unsigned_offsets(file))
return -EINVAL;
@@ -55,6 +66,7 @@ static loff_t lseek_execute(struct file *file, struct inode *inode,
}
return offset;
}
+EXPORT_SYMBOL(vfs_setpos);
/**
* generic_file_llseek_size - generic llseek implementation for regular files
@@ -76,8 +88,6 @@ loff_t
generic_file_llseek_size(struct file *file, loff_t offset, int whence,
loff_t maxsize, loff_t eof)
{
- struct inode *inode = file->f_mapping->host;
-
switch (whence) {
case SEEK_END:
offset += eof;
@@ -97,8 +107,7 @@ generic_file_llseek_size(struct file *file, loff_t offset, int whence,
* like SEEK_SET.
*/
spin_lock(&file->f_lock);
- offset = lseek_execute(file, inode, file->f_pos + offset,
- maxsize);
+ offset = vfs_setpos(file, file->f_pos + offset, maxsize);
spin_unlock(&file->f_lock);
return offset;
case SEEK_DATA:
@@ -120,7 +129,7 @@ generic_file_llseek_size(struct file *file, loff_t offset, int whence,
break;
}
- return lseek_execute(file, inode, offset, maxsize);
+ return vfs_setpos(file, offset, maxsize);
}
EXPORT_SYMBOL(generic_file_llseek_size);
@@ -145,6 +154,26 @@ loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)
EXPORT_SYMBOL(generic_file_llseek);
/**
+ * fixed_size_llseek - llseek implementation for fixed-sized devices
+ * @file: file structure to seek on
+ * @offset: file offset to seek to
+ * @whence: type of seek
+ * @size: size of the file
+ *
+ */
+loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)
+{
+ switch (whence) {
+ case SEEK_SET: case SEEK_CUR: case SEEK_END:
+ return generic_file_llseek_size(file, offset, whence,
+ size, size);
+ default:
+ return -EINVAL;
+ }
+}
+EXPORT_SYMBOL(fixed_size_llseek);
+
+/**
* noop_llseek - No Operation Performed llseek implementation
* @file: file structure to seek on
* @offset: file offset to seek to
@@ -296,7 +325,7 @@ out_putf:
* them to something that fits in "int" so that others
* won't have to do range checks all the time.
*/
-int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count)
+int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
{
struct inode *inode;
loff_t pos;
@@ -477,7 +506,8 @@ SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
if (f.file) {
loff_t pos = file_pos_read(f.file);
ret = vfs_read(f.file, buf, count, &pos);
- file_pos_write(f.file, pos);
+ if (ret >= 0)
+ file_pos_write(f.file, pos);
fdput(f);
}
return ret;
@@ -492,7 +522,8 @@ SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
if (f.file) {
loff_t pos = file_pos_read(f.file);
ret = vfs_write(f.file, buf, count, &pos);
- file_pos_write(f.file, pos);
+ if (ret >= 0)
+ file_pos_write(f.file, pos);
fdput(f);
}
@@ -780,7 +811,8 @@ SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
if (f.file) {
loff_t pos = file_pos_read(f.file);
ret = vfs_readv(f.file, vec, vlen, &pos);
- file_pos_write(f.file, pos);
+ if (ret >= 0)
+ file_pos_write(f.file, pos);
fdput(f);
}
@@ -799,7 +831,8 @@ SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
if (f.file) {
loff_t pos = file_pos_read(f.file);
ret = vfs_writev(f.file, vec, vlen, &pos);
- file_pos_write(f.file, pos);
+ if (ret >= 0)
+ file_pos_write(f.file, pos);
fdput(f);
}
@@ -959,7 +992,8 @@ COMPAT_SYSCALL_DEFINE3(readv, unsigned long, fd,
return -EBADF;
pos = f.file->f_pos;
ret = compat_readv(f.file, vec, vlen, &pos);
- f.file->f_pos = pos;
+ if (ret >= 0)
+ f.file->f_pos = pos;
fdput(f);
return ret;
}
@@ -1025,7 +1059,8 @@ COMPAT_SYSCALL_DEFINE3(writev, unsigned long, fd,
return -EBADF;
pos = f.file->f_pos;
ret = compat_writev(f.file, vec, vlen, &pos);
- f.file->f_pos = pos;
+ if (ret >= 0)
+ f.file->f_pos = pos;
fdput(f);
return ret;
}
@@ -1064,6 +1099,7 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
struct fd in, out;
struct inode *in_inode, *out_inode;
loff_t pos;
+ loff_t out_pos;
ssize_t retval;
int fl;
@@ -1077,12 +1113,14 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
if (!(in.file->f_mode & FMODE_READ))
goto fput_in;
retval = -ESPIPE;
- if (!ppos)
- ppos = &in.file->f_pos;
- else
+ if (!ppos) {
+ pos = in.file->f_pos;
+ } else {
+ pos = *ppos;
if (!(in.file->f_mode & FMODE_PREAD))
goto fput_in;
- retval = rw_verify_area(READ, in.file, ppos, count);
+ }
+ retval = rw_verify_area(READ, in.file, &pos, count);
if (retval < 0)
goto fput_in;
count = retval;
@@ -1099,7 +1137,8 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
retval = -EINVAL;
in_inode = file_inode(in.file);
out_inode = file_inode(out.file);
- retval = rw_verify_area(WRITE, out.file, &out.file->f_pos, count);
+ out_pos = out.file->f_pos;
+ retval = rw_verify_area(WRITE, out.file, &out_pos, count);
if (retval < 0)
goto fput_out;
count = retval;
@@ -1107,7 +1146,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
if (!max)
max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
- pos = *ppos;
if (unlikely(pos + count > max)) {
retval = -EOVERFLOW;
if (pos >= max)
@@ -1126,18 +1164,25 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
if (in.file->f_flags & O_NONBLOCK)
fl = SPLICE_F_NONBLOCK;
#endif
- retval = do_splice_direct(in.file, ppos, out.file, count, fl);
+ file_start_write(out.file);
+ retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
+ file_end_write(out.file);
if (retval > 0) {
add_rchar(current, retval);
add_wchar(current, retval);
fsnotify_access(in.file);
fsnotify_modify(out.file);
+ out.file->f_pos = out_pos;
+ if (ppos)
+ *ppos = pos;
+ else
+ in.file->f_pos = pos;
}
inc_syscr(current);
inc_syscw(current);
- if (*ppos > max)
+ if (pos > max)
retval = -EOVERFLOW;
fput_out:
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.