I am not sure why we have:
"EAGAIN fork() cannot allocate sufficient memory to copy
the parent's page tables and allocate a task structure
or the child."
The text seems to be there from the time when man-pages
were moved to git so there is no history for it.
And it doesn't reflect reality: the kernel reports both
dup_task_struct and dup_mm failures as ENOMEM to the
userspace. This seems to be the case from early 2.x times
so let's simply remove this part.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Verified by experiment on Linux 3.15 and 3.19rc4.
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Let's assume Michael's email address did not change.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Add a reference to the AF_ALG protocol accessible via socket(2).
Signed-off-by: Stephan Mueller <stephan.mueller@atsec.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
With his last patches for getrandom.2 Michael Kerrisk posed a few
questions and left some comments in the man-page. This patch
seeks to clarify the open issues.
72 For example, if the call is interrupted by a signal handler,
73 it may return a partially filled buffer, or fail with the error
74 .BR EINTR .
75 .\" Tested with buffer sizes > 256 bytes: both partial reads
76 .\" and EINTR can occur, with the former being more frequent.
77 .\"
Michael's observation agrees with the code.
For buffer size > 256: If the buffer is still empty EINTR occurs.
If any number of bytes has been read to the buffer, that number
is returned. The comment can be removed.
78 .\" mtk: In the absence of signals, in my testing, even very large reads
79 .\" return full buffers. I found that reads of up to 33554431 always
80 .\" returned a filled buffer. Specifying 'buflen' > 33554431 always
81 .\" returned just 33554431 bytes. (I'm not sure where that number comes
from.
The maximum number of bytes transferred is limited for
/dev/urandom to:
nbytes = min_t(size_t, nbytes, INT_MAX >> (ENTROPY_SHIFT + 3));
// <= 0x1fffff
and for /dev/random to
nbytes = min_t(size_t, nbytes, SEC_XFER_SIZE); // <= 0x200
Lets put this into the NOTES section.
224 When reading from
225 .IR /dev/random ,
226 blocking requests of any size can be interrupted by a signal
227 (the call fails with the error
228 .BR EINTR ).
Thats ok.
82 If the pool has not yet been initialized, then the call blocks, unless
83 .B GRND_RANDOM
84 is specified in
85 .IR flags .
86 .\" FIXME We need a bit more information here.
87 .\" The reader will ask: when is /dev/urandom initialized?
88 .\" There should be some text here to explain that.
Entropy is collected from different sources, e.g.
- time of reaping a thread
- MAC address of a network interfaces
- Allwinner security ID
- ROM content of a firewire device
- ...
When more than 128 bits have been collected, the pool is set
to initialized.
I suggest that detailed information about the initialization
should be provided on the random.4 page.
I added a paragraph in the NOTES section.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Michal Hocko