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db: fix sqlite3 code which manipulates columns.

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Because it used internal routines, it didn't pass operations through the
db hook!  So make it use the generic routines, with the twist that they
are not translated.

And when we use this in a migration hook, we're actually in a
transaction.

This, in turn, introduces an issue: we need to be outside a transaction
to "PRAGMA foreign_keys = OFF", but completing the transaction when
there is a db hook actually enters the io loop, freeing the tmpctx!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2022-09-11 15:21:31 +09:30
committed by Christian Decker
parent d7aa2749c3
commit e853cdc3ff
5 changed files with 109 additions and 107 deletions
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94
db/db_sqlite3.c
View File

@@ -1,7 +1,9 @@
#include "config.h"
#include <ccan/ccan/tal/str/str.h>
#include <common/utils.h>
#include <db/bindings.h>
#include <db/common.h>
#include <db/exec.h>
#include <db/utils.h>
#if HAVE_SQLITE3
@@ -461,7 +463,8 @@ static const char *find_column_name(const tal_t *ctx,
return tal_strndup(ctx, sqlpart + start, *after - start);
}
/* Move table out the way, return columns */
/* Move table out the way, return columns.
* Note: with db_hook, frees tmpctx! */
static char **prepare_table_manip(const tal_t *ctx,
struct db *db, const char *tablename)
{
@@ -488,39 +491,35 @@ static char **prepare_table_manip(const tal_t *ctx,
sql = tal_strdup(tmpctx, (const char *)sqlite3_column_text(stmt, 0));
sqlite3_finalize(stmt);
/* We MUST use generic routines to write to db, since they
* mirror changes to the db hook! */
bracket = strchr(sql, '(');
if (!strstarts(sql, "CREATE TABLE") || !bracket) {
db->error = tal_fmt(db, "strange schema for %s: %s",
tablename, sql);
return NULL;
}
if (!strstarts(sql, "CREATE TABLE") || !bracket)
db_fatal("Bad sql from prepare_table_manip %s: %s",
tablename, sql);
/* Split after ( by commas: any lower case is assumed to be a field */
parts = tal_strsplit(ctx, bracket + 1, ",", STR_EMPTY_OK);
/* Turn off foreign keys first. */
sqlite3_prepare_v2(wrapper->conn, "PRAGMA foreign_keys = OFF;", -1, &stmt, NULL);
if (sqlite3_step(stmt) != SQLITE_DONE)
goto sqlite_stmt_err;
sqlite3_finalize(stmt);
/* Now, we actually need to turn OFF transactions for a moment, as
* this pragma only has an effect outside a tx! */
db_commit_transaction(db);
/* But core insists we're "in a transaction" for all ops, so fake it */
db->in_transaction = "Not really";
/* Turn off foreign keys first. */
db_prepare_for_changes(db);
db_exec_prepared_v2(take(db_prepare_untranslated(db,
"PRAGMA foreign_keys = OFF;")));
db_report_changes(db, NULL, 0);
db->in_transaction = NULL;
db_begin_transaction(db);
cmd = tal_fmt(tmpctx, "ALTER TABLE %s RENAME TO temp_%s;",
tablename, tablename);
sqlite3_prepare_v2(wrapper->conn, cmd, -1, &stmt, NULL);
if (sqlite3_step(stmt) != SQLITE_DONE)
goto sqlite_stmt_err;
sqlite3_finalize(stmt);
/* Make sure we do the same to backup! */
replicate_statement(wrapper, "PRAGMA foreign_keys = OFF;");
replicate_statement(wrapper, cmd);
db_exec_prepared_v2(take(db_prepare_untranslated(db, cmd)));
return parts;
sqlite_stmt_err:
db->error = tal_fmt(db, "%s", sqlite3_errmsg(wrapper->conn));
sqlite3_finalize(stmt);
return tal_free(parts);
}
static bool complete_table_manip(struct db *db,
@@ -528,9 +527,7 @@ static bool complete_table_manip(struct db *db,
const char **coldefs,
const char **oldcolnames)
{
sqlite3_stmt *stmt;
char *create_cmd, *insert_cmd, *drop_cmd;
struct db_sqlite3 *wrapper = (struct db_sqlite3 *)db->conn;
/* Create table */
create_cmd = tal_fmt(tmpctx, "CREATE TABLE %s (", tablename);
@@ -541,13 +538,7 @@ static bool complete_table_manip(struct db *db,
}
tal_append_fmt(&create_cmd, ";");
sqlite3_prepare_v2(wrapper->conn, create_cmd, -1, &stmt, NULL);
if (sqlite3_step(stmt) != SQLITE_DONE)
goto sqlite_stmt_err;
sqlite3_finalize(stmt);
/* Make sure we do the same to backup! */
replicate_statement(wrapper, create_cmd);
db_exec_prepared_v2(take(db_prepare_untranslated(db, create_cmd)));
/* Populate table from old one */
insert_cmd = tal_fmt(tmpctx, "INSERT INTO %s SELECT ", tablename);
@@ -558,33 +549,24 @@ static bool complete_table_manip(struct db *db,
}
tal_append_fmt(&insert_cmd, " FROM temp_%s;", tablename);
sqlite3_prepare_v2(wrapper->conn, insert_cmd, -1, &stmt, NULL);
if (sqlite3_step(stmt) != SQLITE_DONE)
goto sqlite_stmt_err;
sqlite3_finalize(stmt);
replicate_statement(wrapper, insert_cmd);
db_exec_prepared_v2(take(db_prepare_untranslated(db, insert_cmd)));
/* Cleanup temp table */
drop_cmd = tal_fmt(tmpctx, "DROP TABLE temp_%s;", tablename);
sqlite3_prepare_v2(wrapper->conn, drop_cmd, -1, &stmt, NULL);
if (sqlite3_step(stmt) != SQLITE_DONE)
goto sqlite_stmt_err;
sqlite3_finalize(stmt);
replicate_statement(wrapper, drop_cmd);
db_exec_prepared_v2(take(db_prepare_untranslated(db, drop_cmd)));
db_commit_transaction(db);
/* Allow links between them (esp. cascade deletes!) */
sqlite3_prepare_v2(wrapper->conn, "PRAGMA foreign_keys = ON;", -1, &stmt, NULL);
if (sqlite3_step(stmt) != SQLITE_DONE)
goto sqlite_stmt_err;
sqlite3_finalize(stmt);
replicate_statement(wrapper, "PRAGMA foreign_keys = ON;");
db->in_transaction = "Not really";
db_prepare_for_changes(db);
db_exec_prepared_v2(take(db_prepare_untranslated(db,
"PRAGMA foreign_keys = ON;")));
db_report_changes(db, NULL, 0);
db->in_transaction = NULL;
/* migrations are performed inside transactions, so start one. */
db_begin_transaction(db);
return true;
sqlite_stmt_err:
db->error = tal_fmt(db, "%s", sqlite3_errmsg(wrapper->conn));
sqlite3_finalize(stmt);
return false;
}
static bool db_sqlite3_rename_column(struct db *db,
@@ -595,10 +577,11 @@ static bool db_sqlite3_rename_column(struct db *db,
const char **coldefs, **oldcolnames;
bool colname_found = false;
parts = prepare_table_manip(tmpctx, db, tablename);
parts = prepare_table_manip(NULL, db, tablename);
if (!parts)
return false;
tal_steal(tmpctx, parts);
coldefs = tal_arr(tmpctx, const char *, 0);
oldcolnames = tal_arr(tmpctx, const char *, 0);
@@ -643,10 +626,11 @@ static bool db_sqlite3_delete_columns(struct db *db,
const char **coldefs, **oldcolnames;
size_t colnames_found = 0;
parts = prepare_table_manip(tmpctx, db, tablename);
parts = prepare_table_manip(NULL, db, tablename);
if (!parts)
return false;
tal_steal(tmpctx, parts);
coldefs = tal_arr(tmpctx, const char *, 0);
oldcolnames = tal_arr(tmpctx, const char *, 0);