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JDK-8274320: os::fork_and_exec() should be using posix_spawn #5698

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@@ -60,6 +60,7 @@
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <spawn.h>
#include <sys/time.h>
#include <sys/times.h>
#include <sys/types.h>
@@ -1936,40 +1937,16 @@ char** os::get_environ() { return environ; }
// doesn't block SIGINT et al.
// -this function is unsafe to use in non-error situations, mainly
// because the child process will inherit all parent descriptors.
int os::fork_and_exec(const char* cmd, bool prefer_vfork) {
const char * argv[4] = {"sh", "-c", cmd, NULL};

pid_t pid ;

int os::fork_and_exec(const char* cmd) {
const char* argv[4] = {"sh", "-c", cmd, NULL};
pid_t pid = -1;
char** env = os::get_environ();

// Use always vfork on AIX, since its safe and helps with analyzing OOM situations.
// Otherwise leave it up to the caller.
AIX_ONLY(prefer_vfork = true;)
#ifdef __APPLE__
pid = ::fork();
#else
pid = prefer_vfork ? ::vfork() : ::fork();
#endif

if (pid < 0) {
// fork failed
return -1;

} else if (pid == 0) {
// child process

::execve("/bin/sh", (char* const*)argv, env);

// execve failed
::_exit(-1);

} else {
// copied from J2SE ..._waitForProcessExit() in UNIXProcess_md.c; we don't
// care about the actual exit code, for now.

// Note: cast is needed because posix_spawn() requires - for compatibility with ancient
// C-code - a non-const argv/envp pointer array. But it is fine to hand in literal
// strings and just cast the constness away. See also ProcessImpl_md.c.
int rc = ::posix_spawn(&pid, "/bin/sh", NULL, NULL, (char**) argv, env);
if (rc == 0) {
int status;

// Wait for the child process to exit. This returns immediately if
// the child has already exited. */
while (::waitpid(pid, &status, 0) < 0) {
@@ -1979,7 +1956,6 @@ int os::fork_and_exec(const char* cmd, bool prefer_vfork) {
default: return -1;
}
}

if (WIFEXITED(status)) {
// The child exited normally; get its exit code.
return WEXITSTATUS(status);
@@ -1994,6 +1970,9 @@ int os::fork_and_exec(const char* cmd, bool prefer_vfork) {
// Unknown exit code; pass it through
return status;
}
} else {
// Don't log, we are inside error handling
return -1;
}
}

@@ -5616,7 +5616,7 @@ int os::PlatformMonitor::wait(jlong millis) {

// Run the specified command in a separate process. Return its exit value,
// or -1 on failure (e.g. can't create a new process).
int os::fork_and_exec(const char* cmd, bool dummy /* ignored */) {
int os::fork_and_exec(const char* cmd) {
STARTUPINFO si;
PROCESS_INFORMATION pi;
DWORD exit_code;
@@ -515,10 +515,7 @@ class os: AllStatic {

// run cmd in a separate process and return its exit code; or -1 on failures.
// Note: only safe to use in fatal error situations.
// The "prefer_vfork" argument is only used on POSIX platforms to
// indicate whether vfork should be used instead of fork to spawn the
// child process (ignored on AIX, which always uses vfork).
static int fork_and_exec(const char *cmd, bool prefer_vfork = false);
static int fork_and_exec(const char *cmd);

// Call ::exit() on all platforms but Windows
static void exit(int num);
@@ -1684,7 +1684,7 @@ void VM_ReportJavaOutOfMemory::doit() {
#endif
tty->print_cr("\"%s\"...", cmd);

if (os::fork_and_exec(cmd, true) < 0) {
if (os::fork_and_exec(cmd) < 0) {
tty->print_cr("os::fork_and_exec failed: %s (%s=%d)",
os::strerror(errno), os::errno_name(errno), errno);
}