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Add execve / fexecve support to ZIpOS (#727)

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Gavin Hayes 2023-02-24 14:48:24 -05:00 • committed by GitHub
parent 0312898979
commit 5923d483a4
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 143 additions and 22 deletions
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76
libc/calls/fexecve.c
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@ -22,6 +22,7 @@
#include "libc/calls/calls.h"
#include "libc/calls/cp.internal.h"
#include "libc/calls/execve-sysv.internal.h"
#include "libc/calls/internal.h"
#include "libc/calls/struct/stat.internal.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
@ -32,6 +33,8 @@
#include "libc/intrin/strace.internal.h"
#include "libc/intrin/weaken.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/f.h"
#include "libc/sysv/consts/fd.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/mfd.h"
#include "libc/sysv/consts/o.h"
@ -105,13 +108,18 @@ static bool ape_to_elf(void *ape, const size_t apesize) {
return false;
}
static int ape_fd_to_mem_elf_fd(const int infd, char *path) {
/**
* Creates a memfd and copies fd to it.
*
* This does an inplace conversion of APE to ELF when detected!!!!
*/
static int fd_to_mem_fd(const int infd, char *path) {
if (!IsLinux() && !IsFreebsd() || !_weaken(mmap) || !_weaken(munmap)) {
return enosys();
}
struct stat st;
if (sys_fstat(infd, &st) == -1) {
if (fstat(infd, &st) == -1) {
return -1;
}
int fd;
@ -133,7 +141,7 @@ static int ape_fd_to_mem_elf_fd(const int infd, char *path) {
((space = _weaken(mmap)(0, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED,
fd, 0)) != MAP_FAILED)) {
ssize_t readRc;
readRc = sys_pread(infd, space, st.st_size, 0, 0);
readRc = pread(infd, space, st.st_size, 0);
bool success = readRc != -1;
if (success && (st.st_size > 8) && IsAPEMagic(space)) {
success = ape_to_elf(space, st.st_size);
@ -156,7 +164,9 @@ static int ape_fd_to_mem_elf_fd(const int infd, char *path) {
* Executes binary executable at file descriptor.
*
* This is only supported on Linux and FreeBSD. APE binaries are
* supported.
* supported. Zipos is supported. Zipos fds or FD_CLOEXEC APE fds or
* fds that fail fexecve with ENOEXEC are copied to a new memfd (with
* in-memory APE to ELF conversion) and fexecve is (re)attempted.
*
* @param fd is opened executable and current file position is ignored
* @return doesn't return on success, otherwise -1 w/ errno
@ -164,7 +174,7 @@ static int ape_fd_to_mem_elf_fd(const int infd, char *path) {
* @raise ENOSYS on Windows, XNU, OpenBSD, NetBSD, and Metal
*/
int fexecve(int fd, char *const argv[], char *const envp[]) {
int rc;
int rc = 0;
if (!argv || !envp ||
(IsAsan() &&
(!__asan_is_valid_strlist(argv) || !__asan_is_valid_strlist(envp)))) {
@ -172,22 +182,60 @@ int fexecve(int fd, char *const argv[], char *const envp[]) {
} else {
STRACE("fexecve(%d, %s, %s) → ...", fd, DescribeStringList(argv),
DescribeStringList(envp));
rc = fexecve_impl(fd, argv, envp);
if ((errno == ENOEXEC) && (IsLinux() || IsFreebsd())) {
int newfd = -1;
do {
if (!IsLinux() && !IsFreebsd()) {
rc = enosys();
break;
}
if (!__isfdkind(fd, kFdZip)) {
bool memfdReq;
BEGIN_CANCELLATION_POINT;
BLOCK_SIGNALS;
strace_enabled(-1);
memfdReq = ((rc = fcntl(fd, F_GETFD)) != -1) && (rc & FD_CLOEXEC) &&
IsAPEFd(fd);
strace_enabled(+1);
ALLOW_SIGNALS;
END_CANCELLATION_POINT;
if (rc == -1) {
break;
} else if (!memfdReq) {
rc = fexecve_impl(fd, argv, envp);
if (errno != ENOEXEC) {
break;
}
}
}
int newfd;
BEGIN_CANCELLATION_POINT;
BLOCK_SIGNALS;
strace_enabled(-1);
if (IsAPEFd(fd)) {
newfd = ape_fd_to_mem_elf_fd(fd, NULL);
}
newfd = fd_to_mem_fd(fd, NULL);
strace_enabled(+1);
ALLOW_SIGNALS;
END_CANCELLATION_POINT;
if (newfd != -1) {
rc = fexecve_impl(newfd, argv, envp);
if (newfd == -1) {
if (rc == -1) {
errno = ENOEXEC;
}
rc = -1;
break;
}
}
fexecve_impl(newfd, argv, envp);
if (rc == -1) {
errno = ENOEXEC;
}
rc = -1;
const int savedErr = errno;
BEGIN_CANCELLATION_POINT;
BLOCK_SIGNALS;
strace_enabled(-1);
close(newfd);
strace_enabled(+1);
ALLOW_SIGNALS;
END_CANCELLATION_POINT;
errno = savedErr;
} while (0);
}
STRACE("fexecve(%d) failed %d% m", fd, rc);
return rc;