diff options
Diffstat (limited to 'kernel/arch/i386/execregs.c')
| -rw-r--r-- | kernel/arch/i386/execregs.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/kernel/arch/i386/execregs.c b/kernel/arch/i386/execregs.c new file mode 100644 index 000000000000..477cd82989e9 --- /dev/null +++ b/kernel/arch/i386/execregs.c @@ -0,0 +1,132 @@ +/* $NetBSD: execregs.c,v 1.1 2025/02/27 00:55:32 riastradh Exp $ */ + +/*- + * Copyright (c) 2025 The NetBSD Foundation, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__RCSID("$NetBSD: execregs.c,v 1.1 2025/02/27 00:55:32 riastradh Exp $"); + +#include "execregs.h" + +#include <errno.h> +#include <spawn.h> +#include <stddef.h> +#include <unistd.h> + +extern char **environ; + +static unsigned long +nonnull(unsigned long x) +{ + + x |= x << 8; + x |= x << 16; + return x; +} + +int +execregschild(char *path) +{ + register long edi __asm("edi") = nonnull('d'); + register long esi __asm("esi") = nonnull('s'); + /* ebp: frame pointer, can't touch that here, but it'll be nonnull */ + /* ebx: ps_strings, passed to child */ + register long edx __asm("edx") = nonnull('x'); + register long ecx __asm("ecx") = nonnull('c'); + register long eax __asm("eax") = nonnull('a'); + + char *argv[] = {path, NULL}; + char **envp = environ; + + /* + * Not perfect -- compiler might use some registers for + * stack/argument transfers, but all the arguments are nonnull + * so this is probably a good test anyway. + */ + __asm volatile("" : + "+r"(edi), + "+r"(esi), + "+r"(edx), + "+r"(ecx), + "+r"(eax) + :: "memory"); + + return execve(path, argv, envp); +} + +pid_t +spawnregschild(char *path, int fd) +{ + register long edi __asm("edi") = nonnull('d'); + register long esi __asm("esi") = nonnull('s'); + /* ebp: frame pointer, can't touch that here, but it'll be nonnull */ + /* ebx: ps_strings, passed to child */ + register long edx __asm("edx") = nonnull('x'); + register long ecx __asm("ecx") = nonnull('c'); + register long eax __asm("eax") = nonnull('a'); + + char *argv[] = {path, NULL}; + char **envp = environ; + posix_spawn_file_actions_t fileacts; + posix_spawnattr_t attr; + pid_t pid; + int error; + + error = posix_spawn_file_actions_init(&fileacts); + if (error) + goto out; + error = posix_spawn_file_actions_adddup2(&fileacts, fd, STDOUT_FILENO); + if (error) + goto out; + error = posix_spawnattr_init(&attr); + if (error) + goto out; + + /* + * Not perfect -- compiler might use some registers for + * stack/argument transfers, but all the arguments are nonnull + * so this is probably a good test anyway. + */ + __asm volatile("" : + "+r"(edi), + "+r"(esi), + "+r"(edx), + "+r"(ecx), + "+r"(eax) + :: "memory"); + + error = posix_spawn(&pid, path, &fileacts, &attr, argv, envp); + if (error) + goto out; + +out: posix_spawnattr_destroy(&attr); + posix_spawn_file_actions_destroy(&fileacts); + if (error) { + errno = error; + return -1; + } + return 0; +} |