POSIX: make readv() and writev() conform to IEEE Std 1003.1-2001

The standardized version of readv() and writev() take an int as the third
parameter. Arguably a size_t makes more sense, but the standardization bodies
decided otherwise.

The non-standard functions of readv_pos() and writev_pos() have been updated
for consistency. The corresponding _kern_readv() and _kern_writev() internal
functions continue to take the size_t parameter.

The ABI will not change, even though on 64 bit machines the size of the count
parameter will change from 8 to 4 bytes.

The actual use will be slightly different. Like with the size_t argument type,
it will not be possible to give a count lower than 0. If the value is less than
0, then the B_BAD_VALUE/EINVAL error will be set.

Change-Id: I949c8ed67dbc0b4e209768cbdee554c929fc242e
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3770
Reviewed-by: Jérôme Duval <[email protected]>

headers/posix/sys/uio.h

@@ -19,10 +19,10 @@ typedef struct iovec {
 extern "C" {
 #endif
 
-ssize_t readv(int fd, const struct iovec *vector, size_t count);
-ssize_t readv_pos(int fd, off_t pos, const struct iovec *vec, size_t count);
-ssize_t writev(int fd, const struct iovec *vector, size_t count);
-ssize_t writev_pos(int fd, off_t pos, const struct iovec *vec, size_t count);
+ssize_t readv(int fd, const struct iovec *vector, int count);
+ssize_t readv_pos(int fd, off_t pos, const struct iovec *vec, int count);
+ssize_t writev(int fd, const struct iovec *vector, int count);
+ssize_t writev_pos(int fd, off_t pos, const struct iovec *vec, int count);
 
 #ifdef __cplusplus
 }

headers/private/fs_shell/fssh_uio.h

@@ -20,13 +20,13 @@ extern "C" {
 #endif
 
 fssh_ssize_t fssh_readv(int fd, const struct fssh_iovec *vector,
-					fssh_size_t count);
+					int count);
 fssh_ssize_t fssh_readv_pos(int fd, fssh_off_t pos, const struct
-					fssh_iovec *vec, fssh_size_t count);
+					fssh_iovec *vec, int count);
 fssh_ssize_t fssh_writev(int fd, const struct fssh_iovec *vector,
-					fssh_size_t count);
+					int count);
 fssh_ssize_t fssh_writev_pos(int fd, fssh_off_t pos,
-					const struct fssh_iovec *vec, fssh_size_t count);
+					const struct fssh_iovec *vec, int count);
 
 #ifdef __cplusplus
 }