Commit a2019225 authored by Ramon Nou's avatar Ramon Nou
Browse files

fix(client): support spawn descriptor duplication on AArch64

parent eb21ea5c

src/client/posix_spawn.cpp

+31 −12
Changes for src/client/posix_spawn.cpp: 31 added lines, 12 removed lines.
Original line number Diff line number Diff line
@@ -63,17 +63,36 @@ extern char** environ; 


namespace {



static int (*real_posix_spawn)(

        pid_t* __restrict, const char* __restrict,

// AArch64 provides dup3, but not the legacy dup2 system call.

long

spawn_dup2_no_intercept(int oldfd, int newfd) {

    if(oldfd == newfd) {

        const long flags = syscall_no_intercept(SYS_fcntl, oldfd, F_GETFD);

        if(flags < 0) {

            return flags;

        }

        // A spawn dup2 action must keep this descriptor across exec even

        // when no duplication is needed (unlike a plain dup2(fd, fd)).

        const long result = syscall_no_intercept(SYS_fcntl, oldfd, F_SETFD,

                                                 flags & ~FD_CLOEXEC);

        return result < 0 ? result : newfd;

    }

#ifdef SYS_dup2

    return syscall_no_intercept(SYS_dup2, oldfd, newfd);

#else

    return syscall_no_intercept(SYS_dup3, oldfd, newfd, 0);

#endif

}



static int (*real_posix_spawn)(pid_t* __restrict, const char* __restrict,

                               const posix_spawn_file_actions_t* __restrict,

        const posix_spawnattr_t* __restrict, char* const[],

        char* const[]) = nullptr;

                               const posix_spawnattr_t* __restrict,

                               char* const[], char* const[]) = nullptr;



static int (*real_posix_spawnp)(

        pid_t* __restrict, const char* __restrict,

static int (*real_posix_spawnp)(pid_t* __restrict, const char* __restrict,

                                const posix_spawn_file_actions_t* __restrict,

        const posix_spawnattr_t* __restrict, char* const[],

        char* const[]) = nullptr;

                                const posix_spawnattr_t* __restrict,

                                char* const[], char* const[]) = nullptr;



int

dlsym_posix_spawn(pid_t* __restrict pid, const char* __restrict path,
@@ -335,8 +354,8 @@ gkfs_posix_spawn_impl(pid_t* __restrict pid, 
                        break;

                    }

                    case 1: /* spawn_do_dup2 */ {

                        long res = syscall_no_intercept(

                                SYS_dup2, act.action.dup2_action.fd,

                        long res = spawn_dup2_no_intercept(

                                act.action.dup2_action.fd,

                                act.action.dup2_action.newfd);

                        if(res < 0) {

                            fail_child(syscall_error_code(res));
@@ -354,8 +373,8 @@ gkfs_posix_spawn_impl(pid_t* __restrict pid, 
                        }

                        int fd = static_cast<int>(res);

                        if(fd != act.action.open_action.fd) {

                            long dres = syscall_no_intercept(

                                    SYS_dup2, fd, act.action.open_action.fd);

                            long dres = spawn_dup2_no_intercept(

                                    fd, act.action.open_action.fd);

                            syscall_no_intercept(SYS_close, fd);

                            if(dres < 0) {

                                fail_child(syscall_error_code(dres));

tests/integration/rename/test_spawn_dup_actions.py

0 → 100644
+29 −0
Changes for tests/integration/rename/test_spawn_dup_actions.py: 29 added lines, 0 removed lines.
Original line number Diff line number Diff line 
"""Exercise spawn descriptor actions from a virtual working directory."""



import sys





def test_spawn_dup_actions(gkfs_daemon, gkfs_shell, tmp_path):

    output = tmp_path / "spawn-output"

    code = f"""

import os

import sys

os.chdir({str(gkfs_daemon.mountdir)!r})

fd = os.open({str(output)!r}, os.O_CREAT | os.O_RDWR | os.O_CLOEXEC, 0o600)

try:

    # Force GekkoFS's custom spawn path through the virtual cwd. Reuse fd

    # in the child: POSIX requires dup2(fd, fd) to clear FD_CLOEXEC here.

    child = 'import os; os.write(' + str(fd) + ', b"same-fd")'

    pid = os.posix_spawn(sys.executable, [sys.executable, '-c', child],

                         os.environ, file_actions=[(os.POSIX_SPAWN_DUP2, fd, fd)])

    assert os.waitpid(pid, 0)[1] == 0

    pid = os.posix_spawn('/usr/bin/printf', ['printf', '-different-fd'],

                         os.environ, file_actions=[(os.POSIX_SPAWN_DUP2, fd, 1)])

    assert os.waitpid(pid, 0)[1] == 0

    os.lseek(fd, 0, os.SEEK_SET)

    assert os.read(fd, 128) == b'same-fd-different-fd'

finally:

    os.close(fd)

"""

    result = gkfs_shell.run(sys.executable, "-c", code)

    assert result.exit_code == 0, result.stderr.decode()
 
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