#include <unistd.h>
#include <errno.h>
#include <sched.h>
+#include <limits.h>
#include <sys/signal.h>
#include <sys/wait.h>
#include "user.h"
#include "kern_util.h"
#include "user_util.h"
#include "os.h"
+#include "um_malloc.h"
struct helper_data {
void (*pre_exec)(void*);
void *pre_data;
char **argv;
int fd;
+ char *buf;
};
/* Debugging aid, changed only from gdb */
char **argv = data->argv;
int errval;
- if(helper_pause){
+ if (helper_pause){
signal(SIGHUP, helper_hup);
pause();
}
- if(data->pre_exec != NULL)
+ if (data->pre_exec != NULL)
(*data->pre_exec)(data->pre_data);
- execvp(argv[0], argv);
- errval = errno;
- printk("execvp of '%s' failed - errno = %d\n", argv[0], errno);
+ errval = execvp_noalloc(data->buf, argv[0], argv);
+ printk("helper_child - execvp of '%s' failed - errno = %d\n", argv[0], -errval);
os_write_file(data->fd, &errval, sizeof(errval));
kill(os_getpid(), SIGKILL);
- return(0);
+ return 0;
}
/* Returns either the pid of the child process we run or -E* on failure.
- * XXX The alloc_stack here breaks if this is called in the tracing thread */
+ * XXX The alloc_stack here breaks if this is called in the tracing thread, so
+ * we need to receive a preallocated stack (a local buffer is ok). */
int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv,
unsigned long *stack_out)
{
unsigned long stack, sp;
int pid, fds[2], ret, n;
- if((stack_out != NULL) && (*stack_out != 0))
+ if ((stack_out != NULL) && (*stack_out != 0))
stack = *stack_out;
- else stack = alloc_stack(0, __cant_sleep());
- if(stack == 0)
- return(-ENOMEM);
+ else
+ stack = alloc_stack(0, __cant_sleep());
+ if (stack == 0)
+ return -ENOMEM;
ret = os_pipe(fds, 1, 0);
- if(ret < 0){
+ if (ret < 0) {
printk("run_helper : pipe failed, ret = %d\n", -ret);
goto out_free;
}
ret = os_set_exec_close(fds[1], 1);
- if(ret < 0){
+ if (ret < 0) {
printk("run_helper : setting FD_CLOEXEC failed, ret = %d\n",
-ret);
goto out_close;
data.pre_data = pre_data;
data.argv = argv;
data.fd = fds[1];
+ data.buf = __cant_sleep() ? um_kmalloc_atomic(PATH_MAX) :
+ um_kmalloc(PATH_MAX);
pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data);
- if(pid < 0){
+ if (pid < 0) {
ret = -errno;
printk("run_helper : clone failed, errno = %d\n", errno);
- goto out_close;
+ goto out_free2;
}
close(fds[1]);
fds[1] = -1;
- /*Read the errno value from the child.*/
+ /* Read the errno value from the child, if the exec failed, or get 0 if
+ * the exec succeeded because the pipe fd was set as close-on-exec. */
n = os_read_file(fds[0], &ret, sizeof(ret));
- if(n < 0){
- printk("run_helper : read on pipe failed, ret = %d\n", -n);
- ret = n;
- kill(pid, SIGKILL);
- CATCH_EINTR(waitpid(pid, NULL, 0));
- }
- else if(n != 0){
- CATCH_EINTR(n = waitpid(pid, NULL, 0));
- ret = -errno;
- } else {
+ if (n == 0) {
ret = pid;
+ } else {
+ if (n < 0) {
+ printk("run_helper : read on pipe failed, ret = %d\n",
+ -n);
+ ret = n;
+ kill(pid, SIGKILL);
+ }
+ CATCH_EINTR(waitpid(pid, NULL, 0));
}
+out_free2:
+ kfree(data.buf);
out_close:
if (fds[1] != -1)
close(fds[1]);
close(fds[0]);
out_free:
- if(stack_out == NULL)
+ if ((stack_out == NULL) || (*stack_out == 0))
free_stack(stack, 0);
- else *stack_out = stack;
- return(ret);
+ return ret;
}
int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
int pid, status, err;
stack = alloc_stack(stack_order, __cant_sleep());
- if(stack == 0) return(-ENOMEM);
+ if (stack == 0)
+ return -ENOMEM;
sp = stack + (page_size() << stack_order) - sizeof(void *);
pid = clone(proc, (void *) sp, flags | SIGCHLD, arg);
- if(pid < 0){
+ if (pid < 0) {
err = -errno;
printk("run_helper_thread : clone failed, errno = %d\n",
errno);
return err;
}
- if(stack_out == NULL){
+ if (stack_out == NULL) {
CATCH_EINTR(pid = waitpid(pid, &status, 0));
- if(pid < 0){
+ if (pid < 0) {
err = -errno;
printk("run_helper_thread - wait failed, errno = %d\n",
errno);
pid = err;
}
- if(!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
+ if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
printk("run_helper_thread - thread returned status "
"0x%x\n", status);
free_stack(stack, stack_order);
- }
- else *stack_out = stack;
- return(pid);
+ } else
+ *stack_out = stack;
+ return pid;
}
int helper_wait(int pid)
int ret;
CATCH_EINTR(ret = waitpid(pid, NULL, WNOHANG));
- if(ret < 0){
+ if (ret < 0) {
ret = -errno;
printk("helper_wait : waitpid failed, errno = %d\n", errno);
}
- return(ret);
+ return ret;
}