diff options
Diffstat (limited to 'mailutils')
| -rw-r--r-- | mailutils/mail.c | 56 |
1 files changed, 27 insertions, 29 deletions
diff --git a/mailutils/mail.c b/mailutils/mail.c index 9735d48..7e9efdb 100644 --- a/mailutils/mail.c +++ b/mailutils/mail.c @@ -10,35 +10,35 @@ #include "libbb.h" #include "mail.h" -// generic signal handler +// common signal handler static void signal_handler(int signo) { -#define err signo if (SIGALRM == signo) { bb_simple_error_msg_and_die("timed out"); } - // SIGCHLD. reap zombies - if (safe_waitpid(G.helper_pid, &err, WNOHANG) > 0) { - if (WIFSIGNALED(err)) - bb_error_msg_and_die("helper killed by signal %u", WTERMSIG(err)); - if (WIFEXITED(err)) { - G.helper_pid = 0; - if (WEXITSTATUS(err)) - bb_error_msg_and_die("helper exited (%u)", WEXITSTATUS(err)); - } + // SIGCHLD. reap the zombie if we expect one + if (G.helper_pid == 0) + return; +#define status signo + if (safe_waitpid(G.helper_pid, &status, WNOHANG) > 0) { + G.helper_pid = 0; + if (WIFSIGNALED(status)) + bb_error_msg_and_die("helper killed by signal %u", WTERMSIG(status)); + if (WIFEXITED(status) && WEXITSTATUS(status) != 0) + bb_error_msg_and_die("helper exited (%u)", WEXITSTATUS(status)); } -#undef err +#undef status } void FAST_FUNC launch_helper(const char **argv) { - // setup vanilla unidirectional pipes interchange - int i; - int pipes[4]; + pid_t pid; + struct fd_pair child_out; + struct fd_pair child_in; - xpipe(pipes); - xpipe(pipes + 2); + xpiped_pair(child_out); + xpiped_pair(child_in); // NB: handler must be installed before vfork bb_signals(0 @@ -46,25 +46,23 @@ void FAST_FUNC launch_helper(const char **argv) + (1 << SIGALRM) , signal_handler); - G.helper_pid = xvfork(); - - i = (!G.helper_pid) * 2; // for parent:0, for child:2 - close(pipes[i + 1]); // 1 or 3 - closing one write end - close(pipes[2 - i]); // 2 or 0 - closing one read end - xmove_fd(pipes[i], STDIN_FILENO); // 0 or 2 - using other read end - xmove_fd(pipes[3 - i], STDOUT_FILENO); // 3 or 1 - using other write end - // End result: - // parent stdout [3] -> child stdin [2] - // child stdout [1] -> parent stdin [0] - - if (!G.helper_pid) { + G.helper_pid = pid = xvfork(); + if (pid == 0) { // child + close(child_in.wr); + close(child_out.rd); + xmove_fd(child_in.rd, STDIN_FILENO); + xmove_fd(child_out.wr, STDOUT_FILENO); // if parent dies, get SIGTERM prctl(PR_SET_PDEATHSIG, SIGTERM, 0, 0, 0); // try to execute connection helper // NB: SIGCHLD & SIGALRM revert to SIG_DFL on exec BB_EXECVP_or_die((char**)argv); } + close(child_out.wr); + close(child_in.rd); + xmove_fd(child_out.rd, STDIN_FILENO); + xmove_fd(child_in.wr, STDOUT_FILENO); // parent goes on } |