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getcontext.3, signal.7: tfix 

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2020-11-17 09:55:02 +01:00
parent 3a38254934
commit e7a5700f23
2 changed files with 19 additions and 14 deletions
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2
man3/getcontext.3
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@ -110,7 +110,7 @@ The context should have been obtained by a call of
or
.BR makecontext (3),
or received as the third argument to a signal
handler (see the dicussion of the
handler (see the discussion of the
.BR SA_SIGINFO
flag in
.BR sigaction (2)).

31
man7/signal.7
View File

@ -272,7 +272,7 @@ flag and the thread has defined an alternate signal stack (using
then that stack is installed.
.IP c)
Various pieces of signal-related context are saved
into a "hidden" frame that is created on the stack.
into a special frame that is created on the stack.
The saved information includes:
.RS
.IP + 2
@ -280,26 +280,31 @@ the program counter register
(i.e., the address of the next instruction in the main program that
should be executed when the signal handler returns);
.IP +
architecture-specific register state required for resuming the
interrupted program;
.IP +
the thread's current signal mask;
.IP +
the thread's alternate signal stack settings.
.RE
.IP d)
The thread's signal mask is adjusted by adding the signal
(unless the handler was established using the
.BR SA_NODEFER
flag)
as well as any additional signals specified in
.IR act->sa_mask
when
.BR sigaction (2)
was called.
Any signals specified in
.I act\->sa_mask
when registering the handler with
.BR sigprocmask (2)
are added to the thread's signal mask.
The signal being delivered is also
added to the signal mask, unless
.B SA_NODEFER
was specified when registering the handler.
These signals are thus blocked while the handler executes.
.RE
.IP 2.
The kernel constructs a frame for the signal handler on the stack.
Within that frame, the return address points to a piece of user-space code
known as the signal trampoline (described in
The kernel sets the program counter for the thread to point to the first
instruction of the signal handler function,
and configures the return address for that function to point to a piece
of user-space code known as the signal trampoline (described in
.BR sigreturn (2)).
.IP 3.
The kernel passes control back to user-space, where execution
@ -309,7 +314,7 @@ When the signal handler returns, control passes to the signal trampoline code.
.IP 5.
The signal trampoline calls
.BR sigreturn (2),
a system call that uses the information in the "hidden" stack frame
a system call that uses the information in the stack frame created in step 1
to restore the thread's signal mask and alternate stack settings
to their state before the signal handler was called.
Upon completion of the call to