isa/sudo
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Wire up SIGALRM handler

Browse Source 
Set close on exec flag for child side of the socketpair
Fix signal handling when not doing I/O logging
This commit is contained in:
Todd C. Miller
2010-03-06 14:34:23 -05:00
parent d73f580f5a
commit 4e938c0074
2 changed files with 72 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files

114
src/script.c
View File

@@ -111,6 +111,7 @@ static void script_run(const char *path, char *argv[], char *envp[], int);
static void sigchild(int s);
static void sigwinch(int s);
static void sync_winsize(int src, int dst);
static void deliver_signal(pid_t pid, int signo);
/* sudo.c */
extern struct plugin_container_list io_plugins;
@@ -339,6 +340,10 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
sa.sa_handler = sigchild;
sigaction(SIGCHLD, &sa, NULL);
/* Catch SIGALRM for command timeout */
sa.sa_handler = handler;
sigaction(SIGALRM, &sa, NULL);
/* Ignore SIGPIPE from other end of socketpair. */
sa.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sa, NULL);
@@ -392,6 +397,10 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
error(1, "Can't set terminal to raw mode");
}
/* Set command timeout if specified. */
if (ISSET(details->flags, CD_SET_TIMEOUT))
alarm(details->timeout);
/*
* Child will run the command in the pty, parent will pass data
* to and from pty.
@@ -404,6 +413,7 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
case 0:
/* child */
close(sv[0]);
fcntl(sv[1], F_SETFD, FD_CLOEXEC);
if (exec_setup(details) == 0) {
/* headed for execve() */
if (log_io)
@@ -459,7 +469,7 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
zero_bytes(&input, sizeof(input));
zero_bytes(&output, sizeof(output));
for (;;) {
/* XXX - racey */
/* XXX - racey */
if (!relaysig && recvsig != SIGCHLD) {
relaysig = recvsig;
recvsig = 0;
@@ -491,8 +501,14 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
FD_SET(script_fds[SFD_MASTER], fdsw);
}
FD_SET(sv[0], fdsr);
if (relaysig)
FD_SET(sv[0], fdsw);
if (relaysig) {
if (log_io) {
FD_SET(sv[0], fdsw);
} else {
/* nothing listening on sv[0], send directly */
deliver_signal(child, relaysig);
}
}
nready = select(maxfd + 1, fdsr, fdsw, NULL, NULL);
if (nready == -1) {
@@ -506,7 +522,7 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
if (n == -1) {
if (errno == EINTR)
continue;
if (errno != EAGAIN) {
if (log_io && errno != EAGAIN) {
/* Did the other end of the pipe go away? */
cstat->type = CMD_ERRNO;
cstat->val = errno;
@@ -629,14 +645,61 @@ script_execve(struct command_details *details, char *argv[], char *envp[],
return cstat->type == CMD_ERRNO ? -1 : 0;
}
static void
deliver_signal(pid_t pid, int signo)
{
int status;
/* Handle signal from parent. */
sudo_debug(8, "signal %d from parent", signo);
switch (signo) {
case SIGKILL:
_exit(1); /* XXX */
/* NOTREACHED */
case SIGHUP:
case SIGTERM:
case SIGINT:
case SIGQUIT:
case SIGTSTP:
/* relay signal to child */
killpg(pid, signo);
break;
case SIGALRM:
/* command time out, kill child with increasing urgency */
killpg(pid, SIGHUP);
sleep(1);
killpg(pid, SIGTERM);
sleep(1);
killpg(pid, SIGKILL);
break;
case SIGUSR1:
/* foreground process, grant it controlling tty. */
do {
status = tcsetpgrp(script_fds[SFD_SLAVE], pid);
} while (status == -1 && errno == EINTR);
killpg(pid, SIGCONT);
break;
case SIGUSR2:
/* background process, I take controlling tty. */
do {
status = tcsetpgrp(script_fds[SFD_SLAVE], getpid());
} while (status == -1 && errno == EINTR);
killpg(pid, SIGCONT);
break;
default:
warningx("unexpected signal from child: %d", signo);
break;
}
}
int
script_child(const char *path, char *argv[], char *envp[], int backchannel, int rbac)
{
struct command_status cstat;
fd_set *fdsr;
sigaction_t sa;
pid_t pid, self = getpid();
int n, signo, status;
pid_t pid;
int n, status;
recvsig = 0;
@@ -649,8 +712,8 @@ script_child(const char *path, char *argv[], char *envp[], int backchannel, int
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
sa.sa_handler = SIG_DFL;
sigaction(SIGCONT, &sa, NULL);
sigaction(SIGWINCH, &sa, NULL);
sigaction(SIGALRM, &sa, NULL);
/* Ignore any SIGTT{IN,OU} or SIGPIPE we get. */
sa.sa_handler = SIG_IGN;
@@ -774,7 +837,7 @@ script_child(const char *path, char *argv[], char *envp[], int backchannel, int
error(1, "select failed");
}
/* read child status */
/* read command from backchannel, should be a signal */
n = recv(backchannel, &cstat, sizeof(cstat), 0);
if (n == -1) {
if (errno == EINTR)
@@ -786,40 +849,7 @@ script_child(const char *path, char *argv[], char *envp[], int backchannel, int
warningx("unexpected reply type on backchannel: %d", cstat.type);
continue;
}
signo = cstat.val;
/* Handle signal from parent. */
sudo_debug(8, "signal %d from parent", signo);
switch (signo) {
case SIGKILL:
_exit(1); /* XXX */
/* NOTREACHED */
case SIGHUP:
case SIGTERM:
case SIGINT:
case SIGQUIT:
case SIGTSTP:
/* relay signal to child */
killpg(child, signo);
break;
case SIGUSR1:
/* foreground process, grant it controlling tty. */
do {
status = tcsetpgrp(script_fds[SFD_SLAVE], child);
} while (status == -1 && errno == EINTR);
killpg(child, SIGCONT);
break;
case SIGUSR2:
/* background process, I take controlling tty. */
do {
status = tcsetpgrp(script_fds[SFD_SLAVE], self);
} while (status == -1 && errno == EINTR);
killpg(child, SIGCONT);
break;
default:
warningx("unexpected signal from child: %d", signo);
break;
}
deliver_signal(child, cstat.val);
}
_exit(1); /* XXX */