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271 lines (238 loc) · 7.74 KB
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Copy pathproc.c
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271 lines (238 loc) · 7.74 KB
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#include <string.h>
#include <sys/stat.h>
#include "kernel/calls.h"
#include "kernel/fs.h"
#include "fs/proc.h"
#include "fs/path.h"
static int proc_lookup(const char *path, struct proc_entry *entry) {
entry->meta = &proc_root;
char component[MAX_NAME + 1];
int err = 0;
while (path_next_component(&path, component, &err)) {
if (!S_ISDIR(proc_entry_mode(entry))) {
err = _ENOTDIR;
break;
}
unsigned long index = 0;
struct proc_entry next_entry = {0};
char entry_name[MAX_NAME];
while (proc_dir_read(entry, &index, &next_entry)) {
// tack on some dynamically generated attributes
if (next_entry.meta->parent == NULL)
next_entry.meta->parent = entry->meta;
else
// this asserts that an entry has a unique parent
assert(next_entry.meta->parent == entry->meta);
if (next_entry.meta->inode == 0)
next_entry.meta->inode = index + 1;
proc_entry_getname(&next_entry, entry_name);
if (strcmp(entry_name, component) == 0)
goto found;
proc_entry_cleanup(&next_entry);
}
err = _ENOENT;
break;
found:
proc_entry_cleanup(entry);
*entry = next_entry;
}
if (err < 0)
proc_entry_cleanup(entry);
return err;
}
extern const struct fd_ops procfs_fdops;
static struct fd *proc_open(struct mount *UNUSED(mount), const char *path, int UNUSED(flags), int UNUSED(mode)) {
struct proc_entry entry = {0};
int err = proc_lookup(path, &entry);
if (err < 0)
return ERR_PTR(err);
struct fd *fd = fd_create(&procfs_fdops);
fd->proc.entry = entry;
fd->proc.data.data = NULL;
return fd;
}
static int proc_getpath(struct fd *fd, char *buf) {
char *p = buf + MAX_PATH - 1;
size_t n = 0;
p[0] = '\0';
struct proc_entry entry = fd->proc.entry;
while (entry.meta != &proc_root) {
char component[MAX_NAME];
proc_entry_getname(&entry, component);
size_t component_len = strlen(component) + 1; // plus one for the slash
p -= component_len;
n += component_len;
*p = '/';
memcpy(p + 1, component, component_len - 1);
entry.meta = entry.meta->parent;
}
memmove(buf, p, n + 1); // plus one for the null
return 0;
}
static int proc_stat(struct mount *UNUSED(mount), const char *path, struct statbuf *stat) {
struct proc_entry entry = {0};
int err = proc_lookup(path, &entry);
if (err < 0)
return err;
int ret = proc_entry_stat(&entry, stat);
proc_entry_cleanup(&entry);
return ret;
}
static int proc_fstat(struct fd *fd, struct statbuf *stat) {
return proc_entry_stat(&fd->proc.entry, stat);
}
static int proc_refresh_data(struct fd *fd) {
mode_t_ mode = proc_entry_mode(&fd->proc.entry);
if (S_ISDIR(mode))
return _EISDIR;
assert(S_ISREG(mode));
if (fd->proc.data.data == NULL) {
fd->proc.data.capacity = 4096;
fd->proc.data.data = malloc(fd->proc.data.capacity); // default size
}
fd->proc.data.size = 0;
struct proc_entry *entry = &fd->proc.entry;
int err = entry->meta->show(entry, &fd->proc.data);
if (err < 0)
return err;
return 0;
}
static off_t_ proc_seek(struct fd *fd, off_t_ off, int whence) {
int err = proc_refresh_data(fd);
if (err < 0)
return err;
err = generic_seek(fd, off, whence, fd->proc.data.size);
if (err < 0)
return err;
return fd->offset;
}
static ssize_t proc_pread(struct fd *fd, void *buf, size_t bufsize, off_t off) {
if (fd->proc.entry.meta->pread) {
struct proc_data data = {buf, bufsize, bufsize};
return fd->proc.entry.meta->pread(&fd->proc.entry, &data, off);
}
int err = proc_refresh_data(fd);
if (err < 0)
return err;
const char *data = fd->proc.data.data;
assert(data != NULL);
size_t remaining = fd->proc.data.size - off;
if ((size_t) off > fd->proc.data.size)
remaining = 0;
size_t n = bufsize;
if (n > remaining)
n = remaining;
memcpy(buf, data + off, n);
return n;
}
static void proc_buf_write(struct proc_data *buf, const void *data, size_t size, size_t off) {
assert(off <= buf->size);
size_t tidemark = off + size;
if (tidemark > buf->capacity) {
size_t new_capacity = buf->capacity + 1;
while (tidemark > new_capacity)
new_capacity *= 2;
char *new_data = realloc(buf->data, new_capacity);
if (new_data == NULL) {
// just give up, error reporting is a pain
return;
}
buf->data = new_data;
buf->capacity = new_capacity;
}
assert(tidemark <= buf->capacity);
memcpy(buf->data + off, data, size);
if (tidemark > buf->size) {
buf->size = tidemark;
}
}
static ssize_t proc_pwrite(struct fd *fd, const void *buf, size_t bufsize, off_t off) {
mode_t_ mode = proc_entry_mode(&fd->proc.entry);
if (S_ISDIR(mode))
return _EISDIR;
assert(S_ISREG(mode));
if (fd->proc.entry.meta->pwrite) {
struct proc_data data = {(char *) buf, bufsize, bufsize};
return fd->proc.entry.meta->pwrite(&fd->proc.entry, &data, off);
}
if (!fd->proc.entry.meta->update) {
return _EPERM;
}
struct proc_data data = {(char *)buf, bufsize, bufsize};
fd->proc.entry.meta->update(&fd->proc.entry, &data);
return bufsize;
}
static int proc_readdir(struct fd *fd, struct dir_entry *entry) {
struct proc_entry proc_entry = {0};
bool any_left = proc_dir_read(&fd->proc.entry, &fd->offset, &proc_entry);
if (!any_left)
return 0;
proc_entry_getname(&proc_entry, entry->name);
entry->inode = proc_entry.meta->inode;
entry->type = dirent_type_from_mode(proc_entry_mode(&proc_entry));
proc_entry_cleanup(&proc_entry);
return 1;
}
static int proc_close(struct fd *fd) {
if (fd->proc.data.data != NULL)
free(fd->proc.data.data);
proc_entry_cleanup(&fd->proc.entry);
return 0;
}
const struct fd_ops procfs_fdops = {
.pread = proc_pread,
.pwrite = proc_pwrite,
.lseek = proc_seek,
.readdir = proc_readdir,
.close = proc_close,
};
static ssize_t proc_readlink(struct mount *UNUSED(mount), const char *path, char *buf, size_t bufsize) {
struct proc_entry entry = {0};
int err = proc_lookup(path, &entry);
if (err < 0)
return err;
if (!S_ISLNK(proc_entry_mode(&entry))) {
proc_entry_cleanup(&entry);
return _EINVAL;
}
char target[MAX_PATH + 1];
err = entry.meta->readlink(&entry, target);
proc_entry_cleanup(&entry);
if (err < 0)
return err;
if (bufsize > strlen(target))
bufsize = strlen(target);
memcpy(buf, target, bufsize);
return bufsize;
}
static int proc_unlink(struct mount *UNUSED(mount), const char *path) {
struct proc_entry entry = {0};
int err = proc_lookup(path, &entry);
if (err < 0)
return err;
err = _EPERM;
if (entry.meta->unlink)
err = entry.meta->unlink(&entry);
proc_entry_cleanup(&entry);
return err;
}
void proc_buf_append(struct proc_data *buf, const void *data, size_t size) {
proc_buf_write(buf, data, size, buf->size);
}
void proc_printf(struct proc_data *buf, const char *format, ...) {
char data[4096];
va_list args;
va_start(args, format);
size_t size = vsnprintf(data, sizeof(data), format, args);
va_end(args);
proc_buf_append(buf, data, size);
}
const struct fs_ops procfs = {
.name = "proc", .magic = 0x9fa0,
.open = proc_open,
.getpath = proc_getpath,
.stat = proc_stat,
.fstat = proc_fstat,
.readlink = proc_readlink,
.unlink = proc_unlink,
};