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From: Andrey Smirnov <andrew.smirnov@gmail.com>
To: barebox@lists.infradead.org
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: [PATCH v2 12/19] fs: Simplify new position calculation in lseek()
Date: Mon, 28 Jan 2019 22:55:42 -0800	[thread overview]
Message-ID: <20190129065549.29161-13-andrew.smirnov@gmail.com> (raw)
In-Reply-To: <20190129065549.29161-1-andrew.smirnov@gmail.com>

All these checks are really testing is that resulting position is
within [0; f->size] interval. Convert all of the custom checks into a
signle one done after the switch statement to simplify the code.

Note this change also disables the validity check for f->size ==
FILE_SIZE_STREAM and whence == SEEK_END, but lseek(stream_fd, offset,
SEEK_END) wasn't a meaningful operation to begin with, so this
shouldn't be a problem.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 fs/fs.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/fs/fs.c b/fs/fs.c
index 2638e7458..d785c0c3a 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -418,26 +418,23 @@ loff_t lseek(int fildes, loff_t offset, int whence)
 
 	switch (whence) {
 	case SEEK_SET:
-		if (f->size != FILE_SIZE_STREAM && offset > f->size)
-			goto out;
-		if (offset < 0)
-			goto out;
-		pos = offset;
+		pos = 0;
 		break;
 	case SEEK_CUR:
-		if (f->size != FILE_SIZE_STREAM && offset + f->pos > f->size)
-			goto out;
-		pos = f->pos + offset;
+		pos = f->pos;
 		break;
 	case SEEK_END:
-		if (offset > 0)
-			goto out;
-		pos = f->size + offset;
+		pos = f->size;
 		break;
 	default:
 		goto out;
 	}
 
+	pos += offset;
+
+	if (f->size != FILE_SIZE_STREAM && (pos < 0 || pos > f->size))
+		goto out;
+
 	if (fsdrv->lseek) {
 		ret = fsdrv->lseek(&f->fsdev->dev, f, pos);
 		if (ret < 0)
-- 
2.20.1


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  parent reply	other threads:[~2019-01-29  6:56 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-29  6:55 [PATCH v2 00/19] 32-bit lseek and /dev/mem fixes/improvements Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 01/19] commands: Move mem_parse_options() to lib/misc.c Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 02/19] commands: Get rid of mem_rw_buf Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 03/19] commands: Move /dev/mem driver to drivers/misc Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 04/19] nvmem: Do not use DEVFS_IS_CHARACTER_DEV Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 05/19] common: firmware: Don't use FILE_SIZE_STREAM directly Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 06/19] devfs: Fix incorrect error check for cdev->ops->lseek() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 07/19] fs: Update FILE position in lseek() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 08/19] fs: Drop trivial .lseek() implementaitons in FS drivers Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 09/19] devfs: Drop dev_lseek_default() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 10/19] fs: devfs: Change .lseek callbacks to return 'int' Andrey Smirnov
2019-02-04 14:32   ` Sascha Hauer
2019-01-29  6:55 ` [PATCH v2 11/19] fs: Do not use IS_ERR_VALUE() to validate offset in lseek() Andrey Smirnov
2019-01-29  6:55 ` Andrey Smirnov [this message]
2019-01-29  6:55 ` [PATCH v2 13/19] fs: Share code between mem_write()/mem_read() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 14/19] fs: Avoid division in mem_copy() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 15/19] fs: Report actual data processed by mem_copy() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 16/19] fs: Introduce mem_read_nofail() Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 17/19] commands: md: Do not use memmap() Andrey Smirnov
2019-02-04 13:57   ` Sascha Hauer
2019-02-04 19:35     ` Andrey Smirnov
2019-01-29  6:55 ` [PATCH v2 18/19] drivers: mem: Create file to access second half of 64-bit memory Andrey Smirnov
2019-01-29  8:48   ` Sascha Hauer
2019-01-29 20:40     ` Andrey Smirnov
2019-01-29 21:09       ` Sam Ravnborg
2019-01-31 10:54       ` Peter Mamonov
2019-01-31 12:50         ` Peter Mamonov
2019-02-01  7:47           ` Sascha Hauer
2019-02-01 10:25             ` Peter Mamonov
2019-02-02  1:07               ` Andrey Smirnov
2019-02-02  0:35             ` Andrey Smirnov
2019-02-04  7:40               ` Sascha Hauer
2019-01-31 20:17         ` Andrey Smirnov
2019-02-01 10:14           ` Peter Mamonov
2019-01-29  6:55 ` [PATCH v2 19/19] libfile: Fix incorrect lseek check in open_and_lseek() Andrey Smirnov

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