diff options
Diffstat (limited to 'lib/tdb2/test/external-agent.c')
| -rw-r--r-- | lib/tdb2/test/external-agent.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/lib/tdb2/test/external-agent.c b/lib/tdb2/test/external-agent.c new file mode 100644 index 0000000000..055b5de736 --- /dev/null +++ b/lib/tdb2/test/external-agent.c @@ -0,0 +1,250 @@ +#include "external-agent.h" +#include "logging.h" +#include "lock-tracking.h" +#include <sys/types.h> +#include <sys/wait.h> +#include <unistd.h> +#include <err.h> +#include <fcntl.h> +#include <stdlib.h> +#include <limits.h> +#include <string.h> +#include <errno.h> +#include <ccan/tdb2/private.h> +#include <ccan/tap/tap.h> +#include <stdio.h> +#include <stdarg.h> + +static struct tdb_context *tdb; + +static enum TDB_ERROR clear_if_first(int fd, void *arg) +{ +/* We hold a lock offset 63 always, so we can tell if anyone is holding it. */ + struct flock fl; + + fl.l_type = F_WRLCK; + fl.l_whence = SEEK_SET; + fl.l_start = 63; + fl.l_len = 1; + + if (fcntl(fd, F_SETLK, &fl) == 0) { + /* We must be first ones to open it! */ + diag("agent truncating file!"); + if (ftruncate(fd, 0) != 0) { + return TDB_ERR_IO; + } + } + fl.l_type = F_RDLCK; + if (fcntl(fd, F_SETLKW, &fl) != 0) { + return TDB_ERR_IO; + } + return TDB_SUCCESS; +} + +static enum agent_return do_operation(enum operation op, const char *name) +{ + TDB_DATA k; + enum agent_return ret; + TDB_DATA data; + enum TDB_ERROR ecode; + union tdb_attribute cif; + + if (op != OPEN && op != OPEN_WITH_HOOK && !tdb) { + diag("external: No tdb open!"); + return OTHER_FAILURE; + } + + diag("external: %s", operation_name(op)); + + k = tdb_mkdata(name, strlen(name)); + + locking_would_block = 0; + switch (op) { + case OPEN: + if (tdb) { + diag("Already have tdb %s open", tdb->name); + return OTHER_FAILURE; + } + tdb = tdb_open(name, TDB_DEFAULT, O_RDWR, 0, &tap_log_attr); + if (!tdb) { + if (!locking_would_block) + diag("Opening tdb gave %s", strerror(errno)); + forget_locking(); + ret = OTHER_FAILURE; + } else + ret = SUCCESS; + break; + case OPEN_WITH_HOOK: + if (tdb) { + diag("Already have tdb %s open", tdb->name); + return OTHER_FAILURE; + } + cif.openhook.base.attr = TDB_ATTRIBUTE_OPENHOOK; + cif.openhook.base.next = &tap_log_attr; + cif.openhook.fn = clear_if_first; + tdb = tdb_open(name, TDB_DEFAULT, O_RDWR, 0, &cif); + if (!tdb) { + if (!locking_would_block) + diag("Opening tdb gave %s", strerror(errno)); + forget_locking(); + ret = OTHER_FAILURE; + } else + ret = SUCCESS; + break; + case FETCH: + ecode = tdb_fetch(tdb, k, &data); + if (ecode == TDB_ERR_NOEXIST) { + ret = FAILED; + } else if (ecode < 0) { + ret = OTHER_FAILURE; + } else if (!tdb_deq(data, k)) { + ret = OTHER_FAILURE; + free(data.dptr); + } else { + ret = SUCCESS; + free(data.dptr); + } + break; + case STORE: + ret = tdb_store(tdb, k, k, 0) == 0 ? SUCCESS : OTHER_FAILURE; + break; + case TRANSACTION_START: + ret = tdb_transaction_start(tdb) == 0 ? SUCCESS : OTHER_FAILURE; + break; + case TRANSACTION_COMMIT: + ret = tdb_transaction_commit(tdb)==0 ? SUCCESS : OTHER_FAILURE; + break; + case NEEDS_RECOVERY: + ret = tdb_needs_recovery(tdb) ? SUCCESS : FAILED; + break; + case CHECK: + ret = tdb_check(tdb, NULL, NULL) == 0 ? SUCCESS : OTHER_FAILURE; + break; + case CLOSE: + ret = tdb_close(tdb) == 0 ? SUCCESS : OTHER_FAILURE; + tdb = NULL; + break; + case SEND_SIGNAL: + /* We do this async */ + ret = SUCCESS; + break; + default: + ret = OTHER_FAILURE; + } + + if (locking_would_block) + ret = WOULD_HAVE_BLOCKED; + + return ret; +} + +struct agent { + int cmdfd, responsefd; +}; + +/* Do this before doing any tdb stuff. Return handle, or NULL. */ +struct agent *prepare_external_agent(void) +{ + int pid, ret; + int command[2], response[2]; + char name[1+PATH_MAX]; + + if (pipe(command) != 0 || pipe(response) != 0) + return NULL; + + pid = fork(); + if (pid < 0) + return NULL; + + if (pid != 0) { + struct agent *agent = malloc(sizeof(*agent)); + + close(command[0]); + close(response[1]); + agent->cmdfd = command[1]; + agent->responsefd = response[0]; + return agent; + } + + close(command[1]); + close(response[0]); + + /* We want to fail, not block. */ + nonblocking_locks = true; + log_prefix = "external: "; + while ((ret = read(command[0], name, sizeof(name))) > 0) { + enum agent_return result; + + result = do_operation(name[0], name+1); + if (write(response[1], &result, sizeof(result)) + != sizeof(result)) + err(1, "Writing response"); + if (name[0] == SEND_SIGNAL) { + struct timeval ten_ms; + ten_ms.tv_sec = 0; + ten_ms.tv_usec = 10000; + select(0, NULL, NULL, NULL, &ten_ms); + kill(getppid(), SIGUSR1); + } + } + exit(0); +} + +/* Ask the external agent to try to do an operation. */ +enum agent_return external_agent_operation(struct agent *agent, + enum operation op, + const char *name) +{ + enum agent_return res; + unsigned int len; + char *string; + + if (!name) + name = ""; + len = 1 + strlen(name) + 1; + string = malloc(len); + + string[0] = op; + strcpy(string+1, name); + + if (write(agent->cmdfd, string, len) != len + || read(agent->responsefd, &res, sizeof(res)) != sizeof(res)) + res = AGENT_DIED; + + free(string); + return res; +} + +const char *agent_return_name(enum agent_return ret) +{ + return ret == SUCCESS ? "SUCCESS" + : ret == WOULD_HAVE_BLOCKED ? "WOULD_HAVE_BLOCKED" + : ret == AGENT_DIED ? "AGENT_DIED" + : ret == FAILED ? "FAILED" + : ret == OTHER_FAILURE ? "OTHER_FAILURE" + : "**INVALID**"; +} + +const char *operation_name(enum operation op) +{ + switch (op) { + case OPEN: return "OPEN"; + case OPEN_WITH_HOOK: return "OPEN_WITH_HOOK"; + case FETCH: return "FETCH"; + case STORE: return "STORE"; + case CHECK: return "CHECK"; + case TRANSACTION_START: return "TRANSACTION_START"; + case TRANSACTION_COMMIT: return "TRANSACTION_COMMIT"; + case NEEDS_RECOVERY: return "NEEDS_RECOVERY"; + case SEND_SIGNAL: return "SEND_SIGNAL"; + case CLOSE: return "CLOSE"; + } + return "**INVALID**"; +} + +void free_external_agent(struct agent *agent) +{ + close(agent->cmdfd); + close(agent->responsefd); + free(agent); +} |