mirror of
https://github.com/jart/cosmopolitan.git
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Make posix_spawn faster on Windows
This commit is contained in:
Justine Tunney
parent
d6f72aa4a6
commit
ec957491ea
15 changed files with 514 additions and 123 deletions
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@ -17,50 +17,253 @@
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/stdio/posix_spawn.h"
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#include "libc/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/ntspawn.h"
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#include "libc/calls/struct/fd.internal.h"
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#include "libc/calls/struct/sigaction.h"
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#include "libc/calls/struct/sigset.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/fmt/itoa.h"
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#include "libc/fmt/magnumstrs.internal.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/describeflags.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/intrin/weaken.h"
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#include "libc/mem/alloca.h"
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#include "libc/nt/enum/processcreationflags.h"
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#include "libc/nt/enum/startf.h"
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#include "libc/nt/runtime.h"
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#include "libc/nt/struct/processinformation.h"
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#include "libc/nt/struct/startupinfo.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sock/sock.h"
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#include "libc/stdio/posix_spawn.h"
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#include "libc/stdio/posix_spawn.internal.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/sysv/consts/sig.h"
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#include "libc/thread/thread.h"
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#include "libc/thread/tls.h"
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static int RunFileActions(struct _posix_faction *a) {
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int t;
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if (!a) return 0;
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if (RunFileActions(a->next) == -1) return -1;
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switch (a->action) {
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case _POSIX_SPAWN_CLOSE:
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return close(a->fildes);
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case _POSIX_SPAWN_DUP2:
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return dup2(a->fildes, a->newfildes);
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case _POSIX_SPAWN_OPEN:
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if ((t = open(a->path, a->oflag, a->mode)) == -1) return -1;
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if (t != a->fildes) {
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if (dup2(t, a->fildes) == -1) {
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close(t);
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return -1;
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}
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if (close(t) == -1) {
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return -1;
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}
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static void posix_spawn_cleanup3fds(int fds[3]) {
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for (int i = 0; i < 3; ++i) {
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if (fds[i] != -1) {
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int e = errno;
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if (close(fds[i])) {
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errno = e;
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}
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return 0;
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default:
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__builtin_unreachable();
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}
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}
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}
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static const char *DescribePid(char buf[12], int err, int *pid) {
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if (err) return "n/a";
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if (!pid) return "NULL";
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FormatInt32(buf, *pid);
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return buf;
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}
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static textwindows errno_t posix_spawn_windows_impl(
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int *pid, const char *path, const posix_spawn_file_actions_t *file_actions,
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const posix_spawnattr_t *attrp, char *const argv[], char *const envp[]) {
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int i;
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// create file descriptor work area
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char stdio_kind[3] = {kFdEmpty, kFdEmpty, kFdEmpty};
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intptr_t stdio_handle[3] = {-1, -1, -1};
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int close_this_fd_later[3] = {-1, -1, -1};
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for (i = 0; i < 3; ++i) {
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if (g_fds.p[i].kind != kFdEmpty && !(g_fds.p[i].flags & O_CLOEXEC)) {
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stdio_kind[i] = g_fds.p[i].kind;
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stdio_handle[i] = g_fds.p[i].handle;
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}
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}
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// reserve a fake pid for this spawn
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int child = __reservefd(-1);
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// apply user file actions
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if (file_actions) {
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int err = 0;
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for (struct _posix_faction *a = *file_actions; a && !err; a = a->next) {
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switch (a->action) {
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case _POSIX_SPAWN_CLOSE:
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unassert(a->fildes < 3u);
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stdio_kind[a->fildes] = kFdEmpty;
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stdio_handle[a->fildes] = -1;
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break;
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case _POSIX_SPAWN_DUP2:
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unassert(a->newfildes < 3u);
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if (__isfdopen(a->fildes)) {
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stdio_kind[a->newfildes] = g_fds.p[a->fildes].kind;
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stdio_handle[a->newfildes] = g_fds.p[a->fildes].handle;
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} else {
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err = EBADF;
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}
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break;
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case _POSIX_SPAWN_OPEN: {
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int fd, e = errno;
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unassert(a->fildes < 3u);
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if ((fd = open(a->path, a->oflag, a->mode)) != -1) {
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close_this_fd_later[a->fildes] = fd;
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stdio_kind[a->fildes] = g_fds.p[fd].kind;
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stdio_handle[a->fildes] = g_fds.p[fd].handle;
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} else {
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err = errno;
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errno = e;
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}
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break;
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}
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default:
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__builtin_unreachable();
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}
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}
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if (err) {
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posix_spawn_cleanup3fds(close_this_fd_later);
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__releasefd(child);
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return err;
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}
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}
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// create the windows process start info
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int bits;
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char buf[32], *v = 0;
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if (_weaken(socket)) {
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for (bits = i = 0; i < 3; ++i) {
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if (stdio_kind[i] == kFdSocket) {
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bits |= 1 << i;
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}
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}
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FormatInt32(stpcpy(buf, "__STDIO_SOCKETS="), bits);
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v = buf;
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}
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struct NtStartupInfo startinfo = {
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.cb = sizeof(struct NtStartupInfo),
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.dwFlags = kNtStartfUsestdhandles,
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.hStdInput = stdio_handle[0],
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.hStdOutput = stdio_handle[1],
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.hStdError = stdio_handle[2],
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};
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// figure out the flags
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short flags;
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bool bInheritHandles = false;
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uint32_t dwCreationFlags = 0;
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for (i = 0; i < 3; ++i) {
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bInheritHandles |= stdio_handle[i] != -1;
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}
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if (attrp && *attrp && !posix_spawnattr_getflags(attrp, &flags)) {
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if (flags & POSIX_SPAWN_SETSID) {
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dwCreationFlags |= kNtDetachedProcess;
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}
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if (flags & POSIX_SPAWN_SETPGROUP) {
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dwCreationFlags |= kNtCreateNewProcessGroup;
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}
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}
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// launch the process
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int rc, e = errno;
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struct NtProcessInformation procinfo;
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if (!envp) envp = environ;
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rc = ntspawn(path, argv, envp, v, 0, 0, bInheritHandles, dwCreationFlags, 0,
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&startinfo, &procinfo);
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posix_spawn_cleanup3fds(close_this_fd_later);
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if (rc == -1) {
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int err = errno;
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__releasefd(child);
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errno = e;
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return err;
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}
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// track the process
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CloseHandle(procinfo.hThread);
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g_fds.p[child].kind = kFdProcess;
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g_fds.p[child].handle = procinfo.hProcess;
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g_fds.p[child].flags = O_CLOEXEC;
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g_fds.p[child].zombie = false;
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// return the result
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if (pid) *pid = child;
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return 0;
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}
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static textwindows dontinline errno_t posix_spawn_windows(
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int *pid, const char *path, const posix_spawn_file_actions_t *file_actions,
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const posix_spawnattr_t *attrp, char *const argv[], char *const envp[]) {
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int err;
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if (!path || !argv ||
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(IsAsan() && (!__asan_is_valid_str(path) || //
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!__asan_is_valid_strlist(argv) || //
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(envp && !__asan_is_valid_strlist(envp))))) {
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err = EFAULT;
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} else {
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err = posix_spawn_windows_impl(pid, path, file_actions, attrp, argv, envp);
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}
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STRACE("posix_spawn([%s], %#s, %s, %s) → %s",
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DescribePid(alloca(12), err, pid), path, DescribeStringList(argv),
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DescribeStringList(envp), !err ? "0" : _strerrno(err));
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return err;
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}
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static wontreturn void posix_spawn_die(const char *fail_func) {
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STRACE("posix_spawn: %s failed% m", fail_func);
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_Exit(127);
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}
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static void RunUnixFileActions(struct _posix_faction *a) {
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for (; a; a = a->next) {
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switch (a->action) {
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case _POSIX_SPAWN_CLOSE:
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if (close(a->fildes)) {
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posix_spawn_die("close");
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}
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break;
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case _POSIX_SPAWN_DUP2:
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if (dup2(a->fildes, a->newfildes) == -1) {
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posix_spawn_die("dup2");
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}
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break;
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case _POSIX_SPAWN_OPEN: {
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int t;
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if ((t = open(a->path, a->oflag, a->mode)) == -1) {
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posix_spawn_die("open");
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}
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if (t != a->fildes) {
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if (dup2(t, a->fildes) == -1) {
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close(t);
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posix_spawn_die("dup2");
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}
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if (close(t)) {
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posix_spawn_die("close");
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}
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}
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break;
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}
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default:
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__builtin_unreachable();
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}
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}
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}
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/**
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* Spawns process, the POSIX way.
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*
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* This function provides an API for vfork() that's intended to be less
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* terrifying to the uninitiated, since it only lets you define actions
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* that are @vforksafe. This function requires TLS not be disabled.
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* This provides superior process creation performance across systems.
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*
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* Processes are normally spawned by calling fork() and execve(), but
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* that goes slow on Windows if the caller has allocated a nontrivial
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* number of memory mappings, all of which need to be copied into the
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* forked child, only to be destroyed a moment later. On UNIX systems
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* fork() bears a similar cost that's 100x less bad, which is copying
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* the page tables. So what this implementation does is on Windows it
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* calls CreateProcess() directly and on UNIX it uses vfork() if it's
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* possible (XNU and OpenBSD don't have it).
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*
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* If the child process exits with status 127 then use the `--strace`
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* flag to get an explanation of failures that occurred during spawn.
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*
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* @param pid if non-null shall be set to child pid on success
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* @param path is resolved path of program which is not `$PATH` searched
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@ -82,19 +285,20 @@ errno_t posix_spawn(int *pid, const char *path,
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int s, child, policy;
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struct sched_param param;
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struct sigaction dfl = {0};
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if (IsWindows()) {
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return posix_spawn_windows(pid, path, file_actions, attrp, argv, envp);
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}
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if (!(child = vfork())) {
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if (attrp && *attrp) {
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posix_spawnattr_getflags(attrp, &flags);
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if (flags & POSIX_SPAWN_SETSID) {
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if (setsid()) {
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STRACE("posix_spawn fail #%d% m", 1);
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_Exit(127);
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posix_spawn_die("setsid");
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}
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}
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if (flags & POSIX_SPAWN_SETPGROUP) {
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if (setpgid(0, (*attrp)->pgroup)) {
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STRACE("posix_spawn fail #%d% m", 2);
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_Exit(127);
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posix_spawn_die("setpgid");
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}
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}
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if (flags & POSIX_SPAWN_SETSIGMASK) {
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@ -103,47 +307,39 @@ errno_t posix_spawn(int *pid, const char *path,
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}
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if ((flags & POSIX_SPAWN_RESETIDS) &&
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(setgid(getgid()) || setuid(getuid()))) {
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STRACE("posix_spawn fail #%d% m", 3);
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_Exit(127);
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posix_spawn_die("setuid");
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}
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if (flags & POSIX_SPAWN_SETSIGDEF) {
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for (s = 1; s < 32; s++) {
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if (sigismember(&(*attrp)->sigdefault, s)) {
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if (sigaction(s, &dfl, 0) == -1) {
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STRACE("posix_spawn fail #%d% m", 4);
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_Exit(127);
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if (sigaction(s, &dfl, 0)) {
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posix_spawn_die("sigaction");
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}
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}
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}
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}
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}
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if (file_actions) {
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if (RunFileActions(*file_actions) == -1) {
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STRACE("posix_spawn fail #%d% m", 5);
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_Exit(127);
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}
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RunUnixFileActions(*file_actions);
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}
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if (attrp && *attrp) {
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if (flags & POSIX_SPAWN_SETSCHEDULER) {
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posix_spawnattr_getschedpolicy(attrp, &policy);
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posix_spawnattr_getschedparam(attrp, ¶m);
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if (sched_setscheduler(0, policy, ¶m) == -1) {
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STRACE("posix_spawn fail #%d% m", 6);
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_Exit(127);
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posix_spawn_die("sched_setscheduler");
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}
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}
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if (flags & POSIX_SPAWN_SETSCHEDPARAM) {
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posix_spawnattr_getschedparam(attrp, ¶m);
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if (sched_setparam(0, ¶m) == -1) {
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STRACE("posix_spawn fail #%d% m", 7);
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_Exit(127);
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if (sched_setparam(0, ¶m)) {
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posix_spawn_die("sched_setparam");
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}
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}
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}
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if (!envp) envp = environ;
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execve(path, argv, envp);
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STRACE("posix_spawn fail #%d% m", 8);
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_Exit(127);
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posix_spawn_die("execve");
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} else if (child != -1) {
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if (pid) *pid = child;
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return 0;
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