Commit 65c4ca1f authored by RAJAGOPALAN GANGADHARAN's avatar RAJAGOPALAN GANGADHARAN Committed by Henrik Brix Andersen
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fs: open: Add Truncate flag to zfs open 



This commit has added new flag FS_O_TRUNC to support truncation
during file open. Modified fs_open to handle truncation based on
provided flags. Included unit tests for flag behavior with common
filesystems.

Signed-off-by: default avatarRAJAGOPALAN GANGADHARAN <g.raju2000@gmail.com>
parent c36d9ec3

include/zephyr/fs/fs.h

+6 −1
Original line number Diff line number Diff line
@@ -160,8 +160,11 @@ struct fs_statvfs { 
#define FS_O_CREATE     0x10

/** Open/create file for append */

#define FS_O_APPEND     0x20

/** Truncate the file while opening */

#define FS_O_TRUNC      0x40

/** Bitmask for open/create flags */

#define FS_O_FLAGS_MASK 0x30

#define FS_O_FLAGS_MASK 0x70





/** Bitmask for open flags */

#define FS_O_MASK       (FS_O_MODE_MASK | FS_O_FLAGS_MASK)
@@ -268,6 +271,7 @@ static inline void fs_dir_t_init(struct fs_dir_t *zdp) 
 *   - @c FS_O_RDWR open for read/write (<tt>FS_O_READ | FS_O_WRITE</tt>)

 *   - @c FS_O_CREATE create file if it does not exist

 *   - @c FS_O_APPEND move to end of file before each write

 *   - @c FS_O_TRUNC truncate the file

 *

 * @warning If @p flags are set to 0 the function will open file, if it exists

 *          and is accessible, but you will have no read/write access to it.
@@ -284,6 +288,7 @@ static inline void fs_dir_t_init(struct fs_dir_t *zdp) 
 *	   FS_MOUNT_FLAG_READ_ONLY flag;

 * @retval -ENOENT when the file does not exist at the path;

 * @retval -ENOTSUP when not implemented by underlying file system driver;

 * @retval -EACCES when trying to truncate a file without opening it for write.

 * @retval <0 an other negative errno code, depending on a file system back-end.

 */

int fs_open(struct fs_file_t *zfp, const char *file_name, fs_mode_t flags);

subsys/fs/fs.c

+24 −0
Original line number Diff line number Diff line
@@ -134,6 +134,7 @@ int fs_open(struct fs_file_t *zfp, const char *file_name, fs_mode_t flags) 
{

	struct fs_mount_t *mp;

	int rc = -EINVAL;

	bool truncate_file = false;



	if ((file_name == NULL) ||

			(strlen(file_name) <= 1) || (file_name[0] != '/')) {
@@ -160,6 +161,19 @@ int fs_open(struct fs_file_t *zfp, const char *file_name, fs_mode_t flags) 
		return -ENOTSUP;

	}



	if ((flags & FS_O_TRUNC) != 0) {

		if ((flags & FS_O_WRITE) == 0) {

			/** Truncate not allowed when file is not opened for write */

			LOG_ERR("file should be opened for write to truncate!!");

			return -EACCES;

		}

		CHECKIF(mp->fs->truncate == NULL) {

			LOG_ERR("file truncation not supported!!");

			return -ENOTSUP;

		}

		truncate_file = true;

	}



	zfp->mp = mp;

	rc = mp->fs->open(zfp, file_name, flags);

	if (rc < 0) {
@@ -168,6 +182,16 @@ int fs_open(struct fs_file_t *zfp, const char *file_name, fs_mode_t flags) 
		return rc;

	}



	if (truncate_file) {

		/* Truncate the opened file to 0 length */

		rc = mp->fs->truncate(zfp, 0);

		if (rc < 0) {

			LOG_ERR("file truncation failed (%d)", rc);

			zfp->mp = NULL;

			return rc;

		}

	}



	/* Copy flags to zfp for use with other fs_ API calls */

	zfp->flags = flags;

tests/subsys/fs/common/test_fs_open_flags.c

+91 −0
Original line number Diff line number Diff line
@@ -149,9 +149,13 @@ void test_fs_open_flags(void) 
	ZOPEN(&ts, FS_O_READ, -ENOENT);

	ZOPEN(&ts, FS_O_RDWR, -ENOENT);

	ZOPEN(&ts, FS_O_APPEND, -ENOENT);

	ZOPEN(&ts, FS_O_TRUNC, -EACCES);

	ZOPEN(&ts, FS_O_APPEND | FS_O_READ, -ENOENT);

	ZOPEN(&ts, FS_O_APPEND | FS_O_WRITE, -ENOENT);

	ZOPEN(&ts, FS_O_APPEND | FS_O_RDWR, -ENOENT);

	ZOPEN(&ts, FS_O_TRUNC | FS_O_RDWR, -ENOENT);

	ZOPEN(&ts, FS_O_TRUNC | FS_O_APPEND, -EACCES);

	ZOPEN(&ts, FS_O_TRUNC | FS_O_RDWR | FS_O_APPEND, -ENOENT);

	ZEND();
@@ -319,6 +323,73 @@ void test_fs_open_flags(void) 
	ZUNLINK(&ts);

	ZEND();



	/** FS_O_TRUNC tests */

	ZBEGIN("Attempt truncate a new file without write access");

	ZOPEN(&ts, FS_O_CREATE | FS_O_TRUNC, -EACCES);

	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();



	ZBEGIN("Attempt truncate a new file with write access");

	ZOPEN(&ts, FS_O_CREATE | FS_O_WRITE | FS_O_TRUNC, 0);

	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();



	ZBEGIN("Attempt truncate existing with no write access");

	ZMKEMPTY(&ts);

	ZOPEN(&ts, FS_O_TRUNC, -EACCES);

	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();



	ZBEGIN("Attempt truncate existing with write access");

	ZMKEMPTY(&ts);

	ZOPEN(&ts, FS_O_TRUNC | FS_O_WRITE, 0);

	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();



	ZBEGIN("Attempt truncate existing with read access");

	ZMKEMPTY(&ts);

	ZOPEN(&ts, FS_O_READ | FS_O_TRUNC, -EACCES);

	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();



	ZBEGIN("Attempt truncate existing with R/W access");

	ZMKEMPTY(&ts);

	ZOPEN(&ts, FS_O_RDWR | FS_O_TRUNC, 0);

	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();



	ZBEGIN("Attempt read on truncated file but no read access");

	ZMKEMPTY(&ts);

	ZOPEN(&ts, FS_O_WRITE | FS_O_TRUNC, 0);

	#ifndef BYPASS_FS_OPEN_FLAGS_LFS_ASSERT_CRASH

	ZREAD(&ts, -EACCES);

	#else

	TC_PRINT("Read bypassed\n");

	#endif

	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();



	ZBEGIN("Attempt append existing with WRITE access truncated file");

	ZMKEMPTY(&ts);

	ZOPEN(&ts, FS_O_APPEND | FS_O_WRITE | FS_O_TRUNC,  0);

	ZCHKPOS(&ts, 0);

	ZWRITE(&ts, ts.write_size);

	#ifndef BYPASS_FS_OPEN_FLAGS_LFS_ASSERT_CRASH

	ZREAD(&ts, -EACCES);

	#else

	TC_PRINT("Read bypassed\n");

	#endif

	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();





	/* This is simple check by file position, not contents. Since writing

	 * same pattern twice, the position of file should be twice the
@@ -355,4 +426,24 @@ void test_fs_open_flags(void) 
	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();





	ZBEGIN("Check if file is truncated with data");

	/* Prepare file */

	ZUNLINK(&ts);

	ZOPEN(&ts, FS_O_CREATE | FS_O_WRITE, 0);

	ZWRITE(&ts, ts.write_size);

	ZCLOSE(&ts);



	/* Make sure file has the content */

	ZOPEN(&ts, FS_O_CREATE | FS_O_READ, 0);

	ZREAD(&ts, ts.write_size);

	ZCLOSE(&ts);



	ZOPEN(&ts, FS_O_TRUNC | FS_O_RDWR, 0);

	ZCHKPOS(&ts, 0);

	ZREAD(&ts, 0);

	ZCLOSE(&ts);

	ZUNLINK(&ts);

	ZEND();

}

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