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author | Laurent Bercot <ska-skaware@skarnet.org> | 2017-12-21 11:18:28 +0000 |
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committer | Laurent Bercot <ska-skaware@skarnet.org> | 2017-12-21 11:18:28 +0000 |
commit | 2990ce9b390ec1e2bfa1c043c406878e8aff86dd (patch) | |
tree | 270e5e2bfa3cdb2fc795039fc45901d93290567e /src/libposixplz/doublefork.c | |
parent | 933e986a9207d2b61c5119e18603b44b924e7226 (diff) | |
download | skalibs-2990ce9b390ec1e2bfa1c043c406878e8aff86dd.tar.xz |
Big 2.6.3.0 reorganization
- Add libposixplz, update headers
- Add memmem and friends
- Add textmessage to libunixonacid
- Update some sysdeps tests
Diffstat (limited to 'src/libposixplz/doublefork.c')
-rw-r--r-- | src/libposixplz/doublefork.c | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/src/libposixplz/doublefork.c b/src/libposixplz/doublefork.c new file mode 100644 index 0000000..6038a9f --- /dev/null +++ b/src/libposixplz/doublefork.c @@ -0,0 +1,51 @@ +/* ISC license. */ + +#include <sys/wait.h> +#include <unistd.h> +#include <errno.h> +#include <skalibs/uint64.h> +#include <skalibs/allreadwrite.h> +#include <skalibs/djbunix.h> +#include <skalibs/posixplz.h> + +pid_t doublefork () +{ + char pack[8] ; + int fd[2] ; + pid_t child ; + if (pipe(fd) == -1) return -1 ; + child = fork() ; + switch (child) + { + case -1: + { + fd_close(fd[1]) ; + fd_close(fd[0]) ; + return -1 ; + } + case 0: + { + pid_t pid ; + fd_close(fd[0]) ; + pid = fork() ; + switch (pid) + { + case -1: _exit(errno) ; + case 0: fd_close(fd[1]) ; return 0 ; + } + uint64_pack_big(pack, pid) ; + _exit((allwrite(fd[1], pack, 8) < 8) ? errno : 0) ; + } + } + fd_close(fd[1]) ; + { + uint64_t grandchild = 0 ; + int wstat ; + if (allread(fd[0], pack, 8) < 8) grandchild = 1 ; + fd_close(fd[0]) ; + wait_pid(child, &wstat) ; + if (grandchild) return (errno = WIFSIGNALED(wstat) ? EINTR : WEXITSTATUS(wstat), -1) ; + uint64_unpack_big(pack, &grandchild) ; + return (pid_t)grandchild ; + } +} |