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control.c
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control.c
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#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include "pg0.h"
static int null_opener(struct _ce *e, int flags);
static int log_file_reader(control_entry *e, char *buf, size_t size, off_t offset);
static int memory_writer(control_entry *e, const char *buf, size_t size, off_t offset);
static off_t log_file_sizer(control_entry *e);
typedef off_t (*get_size)(control_entry *e);
#define NSIZERS 1
static get_size SIZERS[] = {log_file_sizer};
#define LOG_SIZE_INDEX -1
off_t
get_entry_size(control_entry *e)
{
elog("get_entry_size(rel_path=%s, is_datafile=%d, size=%d)",
e->rel_path, e->is_datafile, e->size);
off_t ret;
if(e->is_datafile && e->size) {
ret = e->n_headers * BLKSZ;
} else if(e->size >= 0) {
ret = e->size;
} else if (e->size < 0) {
int index = -(e->size+1);
elog("...INDEX=%d, size=%d", index, e->size);
if(index < 0 || index > NSIZERS) {
elog("get_entry_size(): index=%d", index);
return -ENOENT;
}
ret = SIZERS[index](e);
} else {
elog("XXX: EIO");
ret = -EIO;
}
return ret;
}
static const char *BACKUP;
static void
elog_entry(const char *msg, control_entry *e)
{
elog("%s: [%s, %s, %s, %ld, 0%o]", msg, e->absolute_path, e->rel_path, e->name,
e->size, e->mode);
}
char *
get_real_path(control_entry *e)
{
/* TODO fail if not a data entry. */
char buf[8192];
snprintf(buf, 8192, "%s/database/%s", BACKUP, e->rel_path);
return strdup(buf);
}
static control_entry root = {.absolute_path = NULL,
.rel_path = "/",
.name = "",
.size=4192,
.mode=S_IFDIR|0700,
.is_datafile = 0,
.children = NULL,
.n_children=0,
.handle=-1,
.write_buf = NULL,
.wb_size=0,
.open=NULL,
.read=NULL,
.write=NULL,
.my_data=NULL,
};
static control_entry log_file = {.absolute_path = NULL,
.rel_path = INTERNAL_LOG_PATH,
.name = INTERNAL_LOG_PATH,
.size = -1,
.mode = S_IFREG|0400,
.is_datafile = 0,
.children = NULL,
.n_children = 0,
.handle = -1,
.write_buf = NULL,
.wb_size = 0,
.open = null_opener,
.read = log_file_reader,
.write = NULL,
.my_data = NULL,
};
static int
null_opener(struct _ce *e, int flags)
{
elog("Null Opener flags=%x rel_path=%s name=%s", flags, e->rel_path, e->name);
return 0;
}
/* Opens real files. */
static int
opener(struct _ce *e, int flags)
{
elog("Opener flas=0x%x %p %s name=%s", flags, e, e->rel_path, e->name);
if(e->size && (e->mode & S_IFMT) == S_IFREG) {
int h = open(e->absolute_path, O_RDONLY);//fi->flags);
if(h==-1) {
elog("Can't open file %s", e->absolute_path);
return -errno;
}
e->handle = h;
elog("...=>%d", h);
if((flags&O_RDWR) == O_RDWR || (flags&O_WRONLY) == O_WRONLY) {
elog("...setting memory writer");
e->write = memory_writer;
}
return 0;
}
elog("...EACCESS");
return -EACCES;
}
static int
opener2(struct _ce *e, int flags)
{
elog("opener2 %s %x", e->rel_path, flags);
return 0;
}
static off_t
log_file_sizer(control_entry *e)
{
elog("log_file_sizer(rel_path=%s)", e->rel_path);
const char *log = elog_get_path();
struct stat st;
if(stat(log, &st) < 0) return -errno;
return st.st_size;
}
static int
log_file_reader(control_entry *e, char *buf, size_t size, off_t offset)
{
elog("log_file_reader(rel_path=%s, size=%ld, offset=%ld)", e->rel_path, size, offset);
const char *log = elog_get_path();
int fd = open(log, O_RDONLY);
if(fd<0) return -errno;
int rc = lseek(fd, offset, SEEK_SET);
if (rc < 0) { close(fd); return -errno; }
rc = read(fd, buf, size);
close(fd);
return rc;
}
static int
reader(control_entry *e, char *buf, size_t size, off_t offset)
{
elog("reader(%s, %ld, %ld)", e->rel_path, size, offset);
off_t rc = lseek(e->handle, offset, SEEK_SET);
if(rc != offset) abort();
int ret=read(e->handle, buf, size);
elog("...%d", ret);
return ret;
}
static int
reader2(control_entry *e, char *buf, size_t size, off_t offset)
{
elog("reader2(rel_path=%s, size=%ld, offset=%ld, :::: wb_size=%ld)", e->rel_path, size, offset, e->wb_size);
size_t sz = MIN(e->wb_size-offset, size);
if(sz<0) sz=0;
elog("...sz=%ld", sz);
memcpy(buf, e->write_buf + offset, sz);
return sz;
}
static int
memory_writer(control_entry *e, const char *buf, size_t size, off_t offset)
{
elog("memory_writer(rel_path=%s, size=%ld, offset=%ld)", e->rel_path, size, offset);
if (e->read != reader2) {
if(e->is_datafile && e->size) {
char *data = read_data_file(e);
if(!data) efail("No data for entry %s", e->name);
size_t real_size = e->n_headers * BLKSZ;
e->write_buf = realloc(e->write_buf, real_size);
e->wb_size = real_size;
memcpy(e->write_buf, data, real_size);
e->size = real_size;
e->is_datafile = 0;
} else {
e->write_buf = realloc(e->write_buf, e->size);
off_t rc = lseek(e->handle, 0, SEEK_SET);
if(rc != 0) abort();
int ret=read(e->handle, e->write_buf, e->size);
if(ret != e->size) efail("...memory writer: %d != %d", ret, e->size);
e->wb_size = e->size;
}
e->read = reader2;
}
e->wb_size = MAX(e->wb_size, offset + size);
e->write_buf = realloc(e->write_buf, e->wb_size);
elog("...wb_size=%ld", e->wb_size);
memcpy(e->write_buf + offset, buf, size);
e->size = e->wb_size;
return size;
}
static void
dump(control_entry *e, int level)
{
if(!e) return;
for(int i=0;i<level;++i) printf(" ");
printf("%s %ld %o %d [%d]\n", e->name, e->size, e->mode, e->is_datafile, e->n_children);
for(int i=0;i<e->n_children;++i) {
dump(e->children[i], level+1);
}
}
static control_entry*
entry_for_path_r(const char *path, control_entry *parent)
{
char buf[8192];
char *p;
char *rest;
if((p=strchr(path, '/'))) {
strncpy(buf, path, p-path);
buf[p-path]=0;
rest = p + 1;
} else {
strcpy(buf, path);
rest = NULL;
}
for(int i=0;i<parent->n_children;++i) {
control_entry *child = parent->children[i];
if(!strcmp(child->name, buf)) {
if(rest)
return entry_for_path_r(rest, child);
else
return child;
}
}
return NULL;
}
control_entry*
entry_for_path(const char *path)
{
if(!strcmp(path, "/")) return &root;
path = path + 1; // path is always absolute
return entry_for_path_r(path, &root);
}
char *
get_file_name(const char *full_path)
{
char *slash = strrchr(full_path, '/');
if(!slash) return strdup(full_path);
return strdup(slash+1);
}
static control_entry*
build_entry(const char *path, size_t size, mode_t mode, bool is_datafile, bool is_virt,
int n_headers, int hdr_off, int hdr_size)
{
if(path[0]=='/') {
elog("build_entry(%s, %ld, 0%o", path, size, mode);
abort();
}
elog("build_entry(path=%s, size=%ld, is_datafile=%d n_headers=%d", path, size, is_datafile, n_headers);
control_entry *ret = malloc(sizeof(control_entry));
if(!ret)abort();
memset(ret, 0, sizeof(control_entry));
ret->rel_path = strdup(path);
ret->name = get_file_name(path);
ret->size = size;
ret->mode = mode;
ret->is_datafile = is_datafile;
ret->children = NULL;
ret->n_children = 0;
ret->n_headers = n_headers;
ret->hdr_off = hdr_off;
ret->hdr_size = hdr_size;
if(is_virt)
ret->absolute_path = NULL;
else
ret->absolute_path = get_real_path(ret);
ret->write_buf = malloc(0);
ret->wb_size = 0;
ret->handle = -1;
if(ret->size && (ret->mode & S_IFMT) == S_IFREG) {
ret->open = opener;
ret->read = reader;
} else if(ret->size == 0 && (ret->mode & S_IFMT) == S_IFREG) {
ret->open = opener2;
ret->read = reader2;
ret->write = memory_writer;
} else {
ret->open = NULL;
ret->read = NULL;
}
ret->my_data= NULL;
return ret;
}
void
grow_children(control_entry *e, control_entry *child)
{
if(!child) {
elog("NO CHILD");
abort();
}
size_t next = e->n_children+1;
e->children = realloc(e->children, sizeof(control_entry*)*next);
e->children[e->n_children] = child;
e->n_children = next;
}
int
remove_child(control_entry *e, control_entry *child)
{
int pos = -1;
for(int i=0;i<e->n_children;++i) {
if(e->children[i] == child) {
pos = i;
break;
}
}
if(pos==-1) return -1;
size_t count = e->n_children-pos-1;
elog("pos=%d n_ch=%d count=%ld", pos, e->n_children, count);
memmove(e->children+pos, e->children+pos+1, sizeof(control_entry*)*count);
return 0;
}
int
CE_link(control_entry *e, const char *to)
{
control_entry *to_e = entry_for_path(to);
if(to_e) return -EACCES;
control_entry *to_parent = parent_entry(to);
control_entry *copy = build_entry(to+1, e->size, e->mode, e->is_datafile, 1, e->n_headers, e->hdr_off, e->hdr_size);
copy->open = opener2;
copy->read = reader2;
copy->write = memory_writer;
grow_children(to_parent, copy);
elog_entry("CE_link source", e);
elog_entry("CE_link copy",copy);
return 0;
}
int
CE_unlink(control_entry *e)
{
char buf[8192];
snprintf(buf, 8192, "/%s", e->rel_path);
control_entry *parent = parent_entry(buf);
if(!parent) {
elog("No parent for %s", buf);
abort();
}
if(remove_child(parent, e) == -1) return -ENOENT;
return 0;
}
int
CE_rename(control_entry *e, const char *to)
{
control_entry *to_e = entry_for_path(to);
if(to_e) {
elog_entry("CE_rename to", to_e);
elog("CE_rename=>already exists %s", to);
//return -EACCES;
CE_unlink(to_e);
}
char buf[8192];
snprintf(buf, 8192, "/%s", e->rel_path);
control_entry *parent = parent_entry(buf);
if(!parent) {
elog("No parent for %s", buf);
abort();
}
if(remove_child(parent, e) == -1) return -ENOENT;
control_entry *to_parent = parent_entry(to);
grow_children(to_parent, e);
e->rel_path = strdup(to+1);
e->name= get_file_name(to);
return 0;
}
int
CE_add_child_dir(control_entry *e, const char *path, mode_t mode)
{
char *fname = get_file_name(path);
for(int i=0;i<e->n_children;++i) {
if(!strcmp(e->name, fname)) return -EEXIST;
}
control_entry *child = build_entry(path+1, 0, mode|S_IFDIR, 0, 1, -1, -1, -1);
elog("...%s: add child %s (%s)", e->rel_path, path, fname);
child->open = NULL;
child->read = NULL;
child->write = NULL;
child->size = 8192;
grow_children(e, child);
return 0;
}
control_entry*
CE_add_child(control_entry *e, const char *path, mode_t mode)
{
char *fname = get_file_name(path);
/* Prevent adding the same entry twice. */
for(int i = 0; i < e->n_children; ++i) {
if(!strcmp(e->name, fname)) return NULL;
}
control_entry *child = build_entry(path+1, 0, mode, 0, 1, -1, -1, -1);
elog_entry("CE_add_child", child);
child->open = opener2;
child->read = reader2;
child->write = memory_writer;
grow_children(e, child);
return child;
}
control_entry *parent_entry(const char *path)
{
if(!strcmp(path, "/")) return NULL;
char *slash = strrchr(path, '/');
if(!slash) return NULL;
char buf[8192];
size_t len = MIN(8191, slash - path)+1;
memcpy(buf, path, len);
buf[len] = 0;
if(len>1 && buf[strlen(buf)-1]=='/') buf[strlen(buf)-1]=0;
return entry_for_path(buf);
}
char JSON_PATH[] = "{\"path\":\"";
char JSON_SIZE[] = ", \"size\":\"";
char JSON_MODE[] = ", \"mode\":\"";
char JSON_IS_DATAFILE[] = ", \"is_datafile\":\"";
char N_HEADERS[] = ",\"n_headers\":\"";
char HDR_OFF[] = ",\"hdr_off\":\"";
char HDR_SIZE[] = ",\"hdr_size\":\"";
static control_entry*
parse_line(char *line)
{
char path[8192];
char buf[8192];
char *end;
char *p = line;
size_t size;
mode_t mode;
int is_datafile;
if(strncmp(p, JSON_PATH, strlen(JSON_PATH)))
abort();
p += strlen(JSON_PATH);
end = strchr(p, '"');
if(!end) abort();
memcpy(path, p, end-p);
path[end-p]=0;
p = strstr(p, JSON_SIZE);
if(!p) abort();
p += strlen(JSON_SIZE);
end = strchr(p, '"');
if(!end) abort();
memcpy(buf, p, end-p);
buf[end-p]=0;
size = atol(buf);
p = strstr(p, JSON_MODE);
if(!p) abort();
p += strlen(JSON_MODE);
end = strchr(p, '"');
if(!end) abort();
memcpy(buf, p, end-p);
buf[end-p]=0;
mode = atol(buf);
p = strstr(p, JSON_IS_DATAFILE);
if(!p) abort();
p += strlen(JSON_IS_DATAFILE);
end = strchr(p, '"');
if(!end) abort();
memcpy(buf, p, end-p);
buf[end-p] = 0;
is_datafile = atoi(buf);
int n_headers = -1;
int hdr_off=-1;
int hdr_size=-1;
if(is_datafile && size) {
p = strstr(p, N_HEADERS);
if(!p) {
elog("SHIT AT %s", line);
abort();
}
p += strlen(N_HEADERS);
end = strchr(p, '"');
if(!end) abort();
memcpy(buf, p, end-p);
buf[end-p] = 0;
n_headers = atoi(buf);
p = strstr(p, HDR_OFF);
if(!p) abort();
p += strlen(HDR_OFF);
end = strchr(p, '"');
if(!end) abort();
memcpy(buf, p, end-p);
buf[end-p] = 0;
hdr_off = atoi(buf);
p = strstr(p, HDR_SIZE);
if(!p) abort();
p += strlen(HDR_SIZE);
end = strchr(p, '"');
if(!end) abort();
memcpy(buf, p, end-p);
buf[end-p] = 0;
hdr_size = atoi(buf);
}
return build_entry(path, size, mode, is_datafile, size==0, n_headers, hdr_off, hdr_size);
}
#define MAX_ENTRIES 1000000
control_entry* entries[MAX_ENTRIES];
int n_entries;
static control_entry*
build_tree(const char *prefix, control_entry *parent)
{
if(!prefix)abort();
if(!parent)abort();
int plen = strlen(prefix);
control_entry *children[1000];
int n_children = 0;
for(int i = 0; i < n_entries; ++i) {
control_entry *entry = entries[i];
if(entry == NULL) continue;
if(!strncmp(prefix, entry->rel_path, plen) && !strchr(entry->rel_path+plen, '/')) {
children[n_children++] = entry;
if(n_children>=1000)abort();
entries[i] = NULL;
}
}
if(parent->children) abort();//we were here already
parent->children = malloc(sizeof(control_entry*)*n_children);
if(!parent->children) abort();
parent->n_children = n_children;
for(int i=0;i<n_children;++i) {
control_entry *child = children[i];
child->name = child->rel_path + plen;
parent->children[i] = child;
char buf[8192];
if((child->mode & S_IFMT) == S_IFDIR) {
snprintf(buf, 8192, "%s/", child->rel_path);
build_tree(buf, child);
}
}
return parent;
}
static control_entry*
read_contents(const char *backup)
{
char buf[8192];
snprintf(buf, 8192, "%s/backup_content.control", backup);
FILE *fi = fopen(buf, "r");
if(!fi) efail("Can't open %s", buf);
n_entries = 0;
while (fgets(buf, 8192, fi)) {
control_entry *entry = parse_line(buf);
entries[n_entries++] = entry;
if(n_entries>=MAX_ENTRIES) abort();
}
fclose(fi);
control_entry *ret = build_tree("", &root);
// check for missed `entries'
for(int i=0;i<MAX_ENTRIES;i++){
if(entries[i]) {
efail("This entry is not part of the tree: %s\n", entries[i]->rel_path);
}
}
return ret;
}
void
open_backup(const char *backup)
{
BACKUP = strdup(backup);
read_contents(backup);
control_entry *log = CE_add_child(&root, INTERNAL_LOG_PATH, 0400);
log->size = LOG_SIZE_INDEX;
log->mode = S_IFREG | log->mode;
log->read = log_file_reader;
elog("ERR=%s, size=%d", log->rel_path, log->size);
}