Add text to CONFORMING TO explaining that the "_np"
suffix is because these functions are non-portable.
Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Perhaps some people might misunderstand memory allocated by
alloca() to be like other memory allocated on the stack: that when
the allocation (or the pointer to the allocation) goes out of
scope, the memory is freed. Add some text to prevent that
misunderstanding.
Reported-by: Robin Kuzmin <kuzmin.robin@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
There is not an acceptable reason to use these functions ever in
new code. For example, just observe the implementation of the
KDF:
/*
* Turn password into DES key
*/
void
passwd2des_internal (char *pw, char *key)
{
int i;
memset (key, 0, 8);
for (i = 0; *pw && i < 8; ++i)
key[i] ^= *pw++ << 1;
des_setparity (key);
}
This kind of nonsense isn't okay in the year 2017. Therefore, we
enlighten our poor users.
[Note from mtk: I think Jason knows that of which he talks.]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
There's a detailed explanation in glob(7), so reuse the same text
glob(3) uses to redirect the reader, rather than inlining a short
explanation.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The double negative is a little confusing, but required. But try
to make the semantics a little clearer in the wording (which is
now closer to the wording in the C standard).
Reported-by: Eric Benton <erbenton@comcast.net>
Reported-by: G. Branden Robinson <g.branden.robinson@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Indicate that strcmp() does not take the locale into account.
Provide a link to strcoll().
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This is inline with POSIX terminology. See also the earlier
commit a00b7454b8 (in 2012)
which fixed most of these cases.
Reported-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
LC_GLOBAL_HANDLE is not defined anywhere, the doc meant LC_GLOBAL_LOCALE
instead.
Reported-by: Solal Pirelli <solal.pirelli@gmail.com>
Signed-off-by: Antonio Ospite <ao2@ao2.it>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
When initializing a new buffer (e.g., that will be sent with
sendmsg(2)), that buffer must first be zero-initialized to
ensure the correct operation of CMSG_NXTHDR().
Verified by experiment, and also by inspection of the glibc
source code:
_EXTERN_INLINE struct cmsghdr *
__NTH (__cmsg_nxthdr (struct msghdr *__mhdr, struct cmsghdr *__cmsg))
{
if ((size_t) __cmsg->cmsg_len < sizeof (struct cmsghdr))
/* The kernel header does this so there may be a reason. */
return (struct cmsghdr *) 0;
[1] __cmsg = (struct cmsghdr *) ((unsigned char *) __cmsg
+ CMSG_ALIGN (__cmsg->cmsg_len));
if ((unsigned char *) (__cmsg + 1) > ((unsigned char *) __mhdr->msg_control
+ __mhdr->msg_controllen)
[2] || ((unsigned char *) __cmsg + CMSG_ALIGN (__cmsg->cmsg_len) // <---
> ((unsigned char *) __mhdr->msg_control + __mhdr->msg_controllen)))
/* No more entries. */
return (struct cmsghdr *) 0;
return __cmsg;
}
At point [1], __cmsg has been updated to point to the next
cmsghdr. The subsequent check at [2] relies on 'cmsg_len'
in the next cmsghdr having some "sensible" value (e.g., 0).
See also https://stackoverflow.com/questions/27601849/cmsg-nxthdr-returns-null-even-though-there-are-more-cmsghdr-objects
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Make it cleared that all of the library functions
described on this page will use the getcwd() system call
if it is present. (The text previously implied that only
the getcwd() library function made use of the system call,
but looking in the glibc source code shows that all of the
functions make use of a generic implementation (__getcwd())
that uses the system call if it is present.)
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The existing text on some of the oddities of the Linux getcwd()
implementation was placed somewhat obtrusively in the DESCRIPTION.
Shift the text to NOTES, and at the same time move the related
discussion of glibc nonconformance to POSIX into BUGS.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The example code currently passes `buflen - 1` to `strncpy`,
however the length parameter to `strncpy` is `size_t`, which is
unsigned. This means that when `buflen` is zero, the cast of `-1`
to unsigned will result in passing `UINT_MAX` as the length.
Obviously, that would be incorrect and could cause `strncpy` to
write well beyond the buffer passed.
The easy solution is to wrap the whole code in the `buflen > 0`
check, rather then just the part of the code that applies the null
terminator.
Signed-off-by: Matthew Kilgore <mattkilgore12@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Since the BSD header has been imported to other C libraries (including
glibc), note that here so people know it isn't BSD-specific.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
* man3/termios.3 (.B TABDLY): Reference to the BUGS section.
(.SH BUGS): New section. Describe an issue on alpha where the XTABS
macro was defined to a value outside TABDLY mask.
Signed-off-by: Eugene Syromyatnikov <evgsyr@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Jakub Wilk