New: Condition for read(2) to return EINVAL is inaccurate
https://bugzilla.kernel.org/show_bug.cgi?id=86061
Bug ID: 86061
Summary: Condition for read(2) to return EINVAL is inaccurate
Product: Documentation
Version: unspecified
Hardware: All
OS: Linux
Status: NEW
Severity: normal
Priority: P1
Component: man-pages
Assignee: documentation_man-pages-ztI5WcYan/[email protected]
Reporter: [email protected]
Regression: No
The man page reads
Quoted 1 line
If count is greater than
SSIZE_MAX, the result is unspecified.
However when we look at the implementation, rw_verify_area() which is common to vfs_read(), vfs_write() and so on actually tests if count fits ssize_t or not and returns EINVAL otherwise.
http://lxr.free-electrons.com/source/fs/read_write.c#L348
So the man page should state so.
This is also important in terms of conformance/getting closer to POSIX. Quotes from POSIX.1-2008:
http://pubs.opengroup.org/onlinepubs/9699919799/functions/read.html
Quoted 1 line
If the value of nbyte is greater than {
SSIZE_MAX}, the result is implementation-defined.
where "implementation-defined" is defined as:
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap01.html#tag_01_05_02
Quoted 3 lines
Describes a value or behavior that is not defined by POSIX.1-2008 but is selected by an implementor. (...snip...)
The implementor shall document such a value or behavior so that it can be used correctly by an application.
So it cannot be just "unspecified".
Moreover, write(2) doesn't say anything about the SSIZE_MAX limit.
Signature · 6 lines
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