d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

system(): Restore behaviour for SIGINT and SIGQUIT.

Browse Source 
As mentioned in r16117 and the book "Advanced Programming in the Unix
Environment" by W. Richard Stevens, we should ignore SIGINT and SIGQUIT
before forking, since it is not guaranteed that the parent process starts
running soon enough.

To avoid calling sigaction() in the vforked child, instead block SIGINT and
SIGQUIT before vfork() and keep the sigaction() to ignore after vfork(). The
FreeBSD kernel discards ignored signals, even if they are blocked;
therefore, it is not necessary to unblock SIGINT and SIGQUIT earlier.
This commit is contained in:
Jilles Tjoelker 2013-09-01 19:59:54 +00:00
parent c672165162
commit 865ca149dc
1 changed files with 2 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lib/libc/stdlib/system.c
View File

@ -59,6 +59,8 @@ __system(const char *command)
(void)sigemptyset(&newsigblock);
(void)sigaddset(&newsigblock, SIGCHLD);
(void)sigaddset(&newsigblock, SIGINT);
(void)sigaddset(&newsigblock, SIGQUIT);
(void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
switch(pid = vfork()) {
case -1: /* error */