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Return ssize_t in fd.c I/O functions. 

In the past, FileRead() and FileWrite() used types based on the Unix
read() and write() functions from before C and POSIX standardization,
though not exactly (we had int for amount instead of unsigned).  In
commit 2d4f1ba6 we changed to the appropriate standard C types, just
like the modern POSIX functions they wrap, but again not exactly: the
return type stayed as int.  In theory, a ssize_t value could be returned
by the underlying call that is too large for an int.

That wasn't really a live bug, because we don't expect PostgreSQL code
to perform reads or writes of gigabytes, and OSes probably apply
internal caps smaller than that anyway.  This change is done on the
principle that the return might as well follow the standard interfaces
consistently.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/1672202.1703441340%40sss.pgh.pa.us
This commit is contained in:
Thomas Munro 2024-03-02 11:59:34 +13:00
parent 655dc31046
commit 653b55b570
2 changed files with 8 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/backend/storage/file/fd.c
View File

@ -2132,11 +2132,11 @@ FileWriteback(File file, off_t offset, off_t nbytes, uint32 wait_event_info)
pgstat_report_wait_end();
}
int
ssize_t
FileReadV(File file, const struct iovec *iov, int iovcnt, off_t offset,
uint32 wait_event_info)
{
int returnCode;
ssize_t returnCode;
Vfd *vfdP;
Assert(FileIsValid(file));
@ -2188,11 +2188,11 @@ retry:
return returnCode;
}
int
ssize_t
FileWriteV(File file, const struct iovec *iov, int iovcnt, off_t offset,
uint32 wait_event_info)
{
int returnCode;
ssize_t returnCode;
Vfd *vfdP;
Assert(FileIsValid(file));

8
src/include/storage/fd.h
View File

@ -107,8 +107,8 @@ extern File PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fil
extern File OpenTemporaryFile(bool interXact);
extern void FileClose(File file);
extern int FilePrefetch(File file, off_t offset, off_t amount, uint32 wait_event_info);
extern int FileReadV(File file, const struct iovec *ioc, int iovcnt, off_t offset, uint32 wait_event_info);
extern int FileWriteV(File file, const struct iovec *ioc, int iovcnt, off_t offset, uint32 wait_event_info);
extern ssize_t FileReadV(File file, const struct iovec *ioc, int iovcnt, off_t offset, uint32 wait_event_info);
extern ssize_t FileWriteV(File file, const struct iovec *ioc, int iovcnt, off_t offset, uint32 wait_event_info);
extern int FileSync(File file, uint32 wait_event_info);
extern int FileZero(File file, off_t offset, off_t amount, uint32 wait_event_info);
extern int FileFallocate(File file, off_t offset, off_t amount, uint32 wait_event_info);
@ -192,7 +192,7 @@ extern int durable_unlink(const char *fname, int elevel);
extern void SyncDataDirectory(void);
extern int data_sync_elevel(int elevel);
static inline int
static inline ssize_t
FileRead(File file, void *buffer, size_t amount, off_t offset,
uint32 wait_event_info)
{
@ -204,7 +204,7 @@ FileRead(File file, void *buffer, size_t amount, off_t offset,
return FileReadV(file, &iov, 1, offset, wait_event_info);
}
static inline int
static inline ssize_t
FileWrite(File file, const void *buffer, size_t amount, off_t offset,
uint32 wait_event_info)
{