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Add memfd fexecve zipos support (#752)

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Gavin Hayes 2023-03-29 21:16:46 -04:00 • committed by GitHub
parent ba42248575
commit 669b4c5f19
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5 changed files with 102 additions and 22 deletions
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49
libc/calls/fexecve.c
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@ -30,6 +30,7 @@
#include "libc/fmt/itoa.h"
#include "libc/intrin/asan.internal.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/intrin/safemacros.internal.h"
#include "libc/intrin/strace.internal.h"
#include "libc/intrin/weaken.h"
#include "libc/str/str.h"
@ -125,9 +126,6 @@ static int fd_to_mem_fd(const int infd, char *path) {
int fd;
if (IsLinux()) {
fd = sys_memfd_create(__func__, MFD_CLOEXEC);
if ((fd != -1) && path) {
FormatInt32(stpcpy(path, "/proc/self/fd/"), fd);
}
} else if (IsFreebsd()) {
fd = sys_shm_open(SHM_ANON, O_CREAT | O_RDWR, 0);
} else {
@ -144,10 +142,22 @@ static int fd_to_mem_fd(const int infd, char *path) {
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);
int flags = fcntl(fd, F_GETFD);
if (success = (flags != -1) &&
(fcntl(fd, F_SETFD, flags & (~FD_CLOEXEC)) != -1) &&
ape_to_elf(space, st.st_size)) {
const int newfd = fcntl(fd, F_DUPFD, 9001);
if (newfd != -1) {
close(fd);
fd = newfd;
}
}
}
const int e = errno;
if ((_weaken(munmap)(space, st.st_size) != -1) && success) {
if (path) {
FormatInt32(stpcpy(path, "COSMOPOLITAN_INIT_ZIPOS="), fd);
}
_unassert(readRc == st.st_size);
return fd;
} else if (!success) {
@ -182,6 +192,7 @@ int fexecve(int fd, char *const argv[], char *const envp[]) {
} else {
STRACE("fexecve(%d, %s, %s) → ...", fd, DescribeStringList(argv),
DescribeStringList(envp));
int savedErr = 0;
do {
if (!IsLinux() && !IsFreebsd()) {
rc = enosys();
@ -200,33 +211,36 @@ int fexecve(int fd, char *const argv[], char *const envp[]) {
if (rc == -1) {
break;
} else if (!memfdReq) {
rc = fexecve_impl(fd, argv, envp);
fexecve_impl(fd, argv, envp);
if (errno != ENOEXEC) {
break;
}
savedErr = ENOEXEC;
}
}
int newfd;
char *path = alloca(PATH_MAX);
BEGIN_CANCELLATION_POINT;
BLOCK_SIGNALS;
strace_enabled(-1);
newfd = fd_to_mem_fd(fd, NULL);
newfd = fd_to_mem_fd(fd, path);
strace_enabled(+1);
ALLOW_SIGNALS;
END_CANCELLATION_POINT;
if (newfd == -1) {
if (rc == -1) {
errno = ENOEXEC;
}
rc = -1;
break;
}
fexecve_impl(newfd, argv, envp);
if (rc == -1) {
errno = ENOEXEC;
size_t numenvs;
for (numenvs = 0; envp[numenvs];) ++numenvs;
const size_t desenvs = min(500, max(numenvs + 1, 2));
static _Thread_local char *envs[500];
memcpy(envs, envp, numenvs * sizeof(char *));
envs[numenvs] = path;
envs[numenvs + 1] = NULL;
fexecve_impl(newfd, argv, envs);
if (!savedErr) {
savedErr = errno;
}
rc = -1;
const int savedErr = errno;
BEGIN_CANCELLATION_POINT;
BLOCK_SIGNALS;
strace_enabled(-1);
@ -234,8 +248,11 @@ int fexecve(int fd, char *const argv[], char *const envp[]) {
strace_enabled(+1);
ALLOW_SIGNALS;
END_CANCELLATION_POINT;
errno = savedErr;
} while (0);
if (savedErr) {
errno = savedErr;
}
rc = -1;
}
STRACE("fexecve(%d) failed %d% m", fd, rc);
return rc;