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#include <camellia/flags.h>
#include <camellia/syscalls.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <camellia/compat.h>
#include <camellia/fs/dir.h>
#include <camellia/fs/misc.h>
void forward_open(hid_t reqh, const char *path, long len, int flags) {
// TODO use threads
// TODO solve for more complex cases, e.g. fs_union
/* done in a separate thread/process because open() can block,
* but that should only hold the caller back, and not the fs driver.
*
* for example, running `httpd` in one term would prevent you from doing
* basically anything on the second term, because fs_dirinject would be
* stuck on open()ing the socket */
if (!_sys_fork(FORK_NOREAP, NULL)) {
_sys_fs_respond(reqh, NULL, _sys_open(path, len, flags), FSR_DELEGATE);
exit(0);
}
close(reqh);
}
void fs_passthru(const char *prefix) {
const size_t buflen = 1024;
char *buf = malloc(buflen);
int prefix_len = prefix ? strlen(prefix) : 0;
if (!buf) exit(1);
for (;;) {
struct ufs_request res;
hid_t reqh = _sys_fs_wait(buf, buflen, &res);
if (reqh < 0) break;
switch (res.op) {
case VFSOP_OPEN:
if (prefix) {
if (prefix_len + res.len > buflen) {
_sys_fs_respond(reqh, NULL, -1, 0);
break;
}
memmove(buf + prefix_len, buf, res.len);
memcpy(buf, prefix, prefix_len);
res.len += prefix_len;
}
forward_open(reqh, buf, res.len, res.flags);
break;
default:
_sys_fs_respond(reqh, NULL, -1, 0);
break;
}
}
exit(0);
}
void fs_union(const char **list) {
struct ufs_request res;
/* the buffer is split into two halves:
* the second one is filled out with the path by fs_wait
* the first one is used for the prepended paths */
const size_t buflen = 1024;
const size_t prelen = 512;
const size_t postlen = buflen - prelen;
char *pre = malloc(buflen);
char *post = pre + prelen;
long ret;
struct dirbuild db;
if (!pre) exit(1);
while (!c0_fs_wait(post, postlen, &res)) {
switch (res.op) {
case VFSOP_OPEN:
if (res.len == 1) { /* root directory */
c0_fs_respond(NULL, 0, 0);
break;
}
ret = -1;
for (size_t i = 0; ret < 0 && list[i]; i++) {
const char *prefix = list[i];
size_t prefixlen = strlen(prefix); // TODO cache
if (prefixlen > prelen) continue;
char *path = post - prefixlen;
memcpy(path, prefix, prefixlen);
ret = _sys_open(path, prefixlen + res.len, res.flags);
post[res.len] = '\0';
}
if (ret < 0) ret = -1;
c0_fs_respond(NULL, ret, FSR_DELEGATE);
break;
case VFSOP_READ:
case VFSOP_GETSIZE:
if (res.capacity > buflen)
res.capacity = buflen;
bool end = false;
char *target = res.op == VFSOP_READ ? pre : NULL;
dir_start(&db, res.offset, target, res.capacity);
for (size_t i = 0; !end && list[i]; i++) {
const char *prefix = list[i];
size_t prefixlen = strlen(prefix);
// TODO only open the directories once
// TODO ensure trailing slash
hid_t h = _sys_open(prefix, prefixlen, OPEN_READ);
if (h < 0) continue;
end = end || dir_append_from(&db, h);
_sys_close(h);
}
c0_fs_respond(target, dir_finish(&db), 0);
break;
default:
c0_fs_respond(NULL, -1, 0);
break;
}
}
exit(0);
}
hid_t ufs_wait(char *buf, size_t len, struct ufs_request *req) {
hid_t reqh;
for (;;) {
reqh = _sys_fs_wait(buf, len, req);
if (reqh < 0) break;
if (req->op == VFSOP_OPEN) {
if (req->len == len) {
_sys_fs_respond(reqh, NULL, -ENAMETOOLONG, 0);
continue;
}
buf[req->len] = '\0';
// TODO ensure passed paths don't have null bytes in them in the kernel
}
break;
}
return reqh;
}
int mount_at(const char *path) {
hid_t h;
int ret = _sys_fork(FORK_NEWFS, &h);
if (ret == 0) {
_klogf("%s: impl", path);
setproctitle("%s", path);
} else if (ret > 0) {
_sys_mount(h, path, strlen(path));
close(h);
} else {
_sys_mount(HANDLE_NULLFS, path, strlen(path));
}
return ret;
}
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