lnav/src/environ_vtab.cc
2015-03-28 18:41:06 -07:00

320 lines
8.7 KiB
C++

/**
* Copyright (c) 2014, Timothy Stack
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of Timothy Stack nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include <assert.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "auto_mem.hh"
#include "lnav_log.hh"
#include "sql_util.hh"
#include "environ_vtab.hh"
using namespace std;
extern char **environ;
const char *ENVIRON_CREATE_STMT = "\
-- Access lnav's environment variables through this table.\n\
CREATE TABLE environ (\n\
name text PRIMARY KEY,\n\
value text\n\
);\n\
";
struct vtab {
sqlite3_vtab base;
sqlite3 * db;
};
struct vtab_cursor {
sqlite3_vtab_cursor base;
char **env_cursor;
};
static int vt_destructor(sqlite3_vtab *p_svt);
static int vt_create(sqlite3 *db,
void *pAux,
int argc, const char *const *argv,
sqlite3_vtab **pp_vt,
char **pzErr)
{
vtab *p_vt;
/* Allocate the sqlite3_vtab/vtab structure itself */
p_vt = (vtab *)sqlite3_malloc(sizeof(*p_vt));
if (p_vt == NULL) {
return SQLITE_NOMEM;
}
memset(&p_vt->base, 0, sizeof(sqlite3_vtab));
p_vt->db = db;
*pp_vt = &p_vt->base;
int rc = sqlite3_declare_vtab(db, ENVIRON_CREATE_STMT);
return rc;
}
static int vt_destructor(sqlite3_vtab *p_svt)
{
vtab *p_vt = (vtab *)p_svt;
/* Free the SQLite structure */
sqlite3_free(p_vt);
return SQLITE_OK;
}
static int vt_connect(sqlite3 *db, void *p_aux,
int argc, const char *const *argv,
sqlite3_vtab **pp_vt, char **pzErr)
{
return vt_create(db, p_aux, argc, argv, pp_vt, pzErr);
}
static int vt_disconnect(sqlite3_vtab *pVtab)
{
return vt_destructor(pVtab);
}
static int vt_destroy(sqlite3_vtab *p_vt)
{
return vt_destructor(p_vt);
}
static int vt_next(sqlite3_vtab_cursor *cur);
static int vt_open(sqlite3_vtab *p_svt, sqlite3_vtab_cursor **pp_cursor)
{
vtab *p_vt = (vtab *)p_svt;
p_vt->base.zErrMsg = NULL;
vtab_cursor *p_cur = (vtab_cursor *)new vtab_cursor();
if (p_cur == NULL) {
return SQLITE_NOMEM;
} else {
*pp_cursor = (sqlite3_vtab_cursor *)p_cur;
p_cur->base.pVtab = p_svt;
p_cur->env_cursor = environ;
vt_next((sqlite3_vtab_cursor *)p_cur);
}
return SQLITE_OK;
}
static int vt_close(sqlite3_vtab_cursor *cur)
{
vtab_cursor *p_cur = (vtab_cursor *)cur;
/* Free cursor struct. */
delete p_cur;
return SQLITE_OK;
}
static int vt_eof(sqlite3_vtab_cursor *cur)
{
vtab_cursor *vc = (vtab_cursor *)cur;
return vc->env_cursor[0] == NULL;
}
static int vt_next(sqlite3_vtab_cursor *cur)
{
vtab_cursor *vc = (vtab_cursor *)cur;
if (vc->env_cursor[0] != NULL) {
vc->env_cursor += 1;
}
return SQLITE_OK;
}
static int vt_column(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int col)
{
vtab_cursor *vc = (vtab_cursor *)cur;
const char *eq = strchr(vc->env_cursor[0], '=');
switch (col) {
case 0:
sqlite3_result_text(ctx,
vc->env_cursor[0], eq - vc->env_cursor[0],
SQLITE_TRANSIENT);
break;
case 1:
sqlite3_result_text(ctx, eq + 1, -1, SQLITE_TRANSIENT);
break;
}
return SQLITE_OK;
}
static int vt_rowid(sqlite3_vtab_cursor *cur, sqlite_int64 *p_rowid)
{
vtab_cursor *p_cur = (vtab_cursor *)cur;
*p_rowid = (int64_t)p_cur->env_cursor[0];
return SQLITE_OK;
}
static int vt_best_index(sqlite3_vtab *tab, sqlite3_index_info *p_info)
{
return SQLITE_OK;
}
static int vt_filter(sqlite3_vtab_cursor *p_vtc,
int idxNum, const char *idxStr,
int argc, sqlite3_value **argv)
{
return SQLITE_OK;
}
static int vt_update(sqlite3_vtab *tab,
int argc,
sqlite3_value **argv,
sqlite_int64 *rowid)
{
const char *name = (
argc > 2 ? (const char *)sqlite3_value_text(argv[2]) : NULL);
vtab *p_vt = (vtab *)tab;
int retval = SQLITE_ERROR;
if (argc != 1 &&
(argc < 3 ||
sqlite3_value_type(argv[2]) == SQLITE_NULL ||
sqlite3_value_type(argv[3]) == SQLITE_NULL ||
sqlite3_value_text(argv[2])[0] == '\0')) {
tab->zErrMsg = sqlite3_mprintf(
"A non-empty name and value must be provided when inserting an "
"environment variable");
return SQLITE_ERROR;
}
if (name != NULL && strchr(name, '=') != NULL) {
tab->zErrMsg = sqlite3_mprintf(
"Environment variable names cannot contain an equals sign (=)");
return SQLITE_ERROR;
}
if (sqlite3_value_type(argv[0]) != SQLITE_NULL) {
int64_t index = sqlite3_value_int64(argv[0]);
const char *var = (const char *)index;
const char *eq = strchr(var, '=');
size_t namelen = eq - var;
char name[namelen + 1];
memcpy(name, var, namelen);
name[namelen] = '\0';
unsetenv(name);
retval = SQLITE_OK;
} else if (name != NULL && getenv(name) != NULL) {
#ifdef SQLITE_FAIL
int rc;
rc = sqlite3_vtab_on_conflict(p_vt->db);
switch (rc) {
case SQLITE_FAIL:
case SQLITE_ABORT:
tab->zErrMsg = sqlite3_mprintf(
"An environment variable with the name '%s' already exists",
name);
return rc;
case SQLITE_IGNORE:
return SQLITE_OK;
case SQLITE_REPLACE:
break;
default:
return rc;
}
#endif
}
if (name != NULL && argc == 4) {
const unsigned char *value = sqlite3_value_text(argv[3]);
setenv((const char *)name, (const char *)value, 1);
return SQLITE_OK;
}
return retval;
}
static sqlite3_module vtab_module = {
0, /* iVersion */
vt_create, /* xCreate - create a vtable */
vt_connect, /* xConnect - associate a vtable with a connection */
vt_best_index, /* xBestIndex - best index */
vt_disconnect, /* xDisconnect - disassociate a vtable with a connection */
vt_destroy, /* xDestroy - destroy a vtable */
vt_open, /* xOpen - open a cursor */
vt_close, /* xClose - close a cursor */
vt_filter, /* xFilter - configure scan constraints */
vt_next, /* xNext - advance a cursor */
vt_eof, /* xEof - inidicate end of result set*/
vt_column, /* xColumn - read data */
vt_rowid, /* xRowid - read data */
vt_update, /* xUpdate - write data */
NULL, /* xBegin - begin transaction */
NULL, /* xSync - sync transaction */
NULL, /* xCommit - commit transaction */
NULL, /* xRollback - rollback transaction */
NULL, /* xFindFunction - function overloading */
};
int register_environ_vtab(sqlite3 *db)
{
auto_mem<char, sqlite3_free> errmsg;
int rc;
rc = sqlite3_create_module(db, "environ_vtab_impl", &vtab_module, NULL);
assert(rc == SQLITE_OK);
if ((rc = sqlite3_exec(db,
"CREATE VIRTUAL TABLE environ USING environ_vtab_impl()",
NULL, NULL, errmsg.out())) != SQLITE_OK) {
fprintf(stderr, "wtf %s\n", errmsg.in());
}
return rc;
}