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Diffstat (limited to 'runtime/transport/transport.c')
| -rw-r--r-- | runtime/transport/transport.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/runtime/transport/transport.c b/runtime/transport/transport.c new file mode 100644 index 00000000..080469a2 --- /dev/null +++ b/runtime/transport/transport.c @@ -0,0 +1,166 @@ +#ifndef _TRANSPORT_TRANSPORT_C_ /* -*- linux-c -*- */ +#define _TRANSPORT_TRANSPORT_C_ + +/* + * transport.c - stp transport functions + * + * Copyright (C) IBM Corporation, 2005 + * Copyright (C) Redhat Inc, 2005 + * + * This file is released under the GPL. + */ + +/** @file transport.c + * @brief Systemtap transport functions + */ + +/** @addtogroup transport Transport Functions + * @{ + */ + +#include <linux/delay.h> +#include "transport.h" +#include "control.h" +#include "relayfs.c" + +/** @file transport.c + * @brief transport functions + */ +/** @addtogroup io transport + * transport functions + * @{ + */ + +/* transport-related data for this probe */ +struct stp_transport *t; + +/* forward declaration of probe-defined exit function */ +static void probe_exit(void); + +/** + * _stp_handle_buf_info - handle relayfs buffer info command + */ +static void _stp_handle_buf_info(int pid, struct buf_info *in) +{ + struct buf_info out; + BUG_ON(!(t && t->chan)); + + out.cpu = in->cpu; + out.produced = atomic_read(&t->chan->buf[in->cpu]->subbufs_produced); + out.consumed = atomic_read(&t->chan->buf[in->cpu]->subbufs_consumed); + + _stp_ctrl_send(STP_BUF_INFO, &out, sizeof(out), pid); +} + +/** + * _stp_handle_subbufs_consumed - handle relayfs subbufs consumed command + */ +static void _stp_handle_subbufs_consumed(int pid, struct consumed_info *info) +{ + BUG_ON(!(t && t->chan)); + relay_subbufs_consumed(t->chan, info->cpu, info->consumed); +} + +/** + * _stp_handle_exit - handle exit command + */ +static void _stp_handle_exit(int pid) +{ + BUG_ON(!t); + probe_exit(); + _stp_transport_flush(); + _stp_ctrl_send(STP_EXIT, __this_module.name, + strlen(__this_module.name) + 1, pid); +} + +/** + * _stp_cmd_handler - control channel command handler callback + * @pid: the pid of the daemon the command was sent from + * @cmd: the command id + * @data: command-specific data + * + * This function must return 0 if the command was handled, nonzero + * otherwise. + */ +static int _stp_cmd_handler(int pid, int cmd, void *data) +{ + int err = 0; + + switch (cmd) { + case STP_BUF_INFO: + _stp_handle_buf_info(pid, data); + break; + case STP_SUBBUFS_CONSUMED: + _stp_handle_subbufs_consumed(pid, data); + break; + case STP_EXIT: + _stp_handle_exit(pid); + break; + default: + err = -1; + break; + } + + return err; +} + +/** + * _stp_transport_close - close netlink and relayfs channels + * + * This must be called after all I/O is done, probably at the end + * of module cleanup. + */ +void _stp_transport_close() +{ + if (!t) + return; + + _stp_ctrl_unregister(t->pid); + if (!_stp_streaming()) + _stp_relayfs_close(t->chan, t->dir); + + /* in case the module has been manually removed */ + _stp_ctrl_send(STP_EXIT, __this_module.name, + strlen(__this_module.name) + 1, t->pid); + kfree(t); +} + +/** + * _stp_transport_open - open netlink and relayfs channels + * @n_subbufs: number of relayfs sub-buffers + * @subbuf_size: size of relayfs sub-buffers + * @pid: daemon pid + * + * Returns negative on failure, 0 otherwise. + * + * This function registers the probe with the control channel, + * and if the probe output will not be 'streaming', creates a + * relayfs channel for it. This must be called before any I/O is + * done, probably at the start of module initialization. + */ +int _stp_transport_open(unsigned n_subbufs, unsigned subbuf_size, int pid) +{ + BUG_ON(!(n_subbufs && subbuf_size)); + + t = kcalloc(1, sizeof(struct stp_transport), GFP_KERNEL); + if (!t) + return -ENOMEM; + + t->pid = pid; + _stp_ctrl_register(t->pid, _stp_cmd_handler); + + if (_stp_streaming()) + return 0; + + t->chan = _stp_relayfs_open(n_subbufs, subbuf_size, t->pid, &t->dir); + if (!t->chan) { + _stp_ctrl_unregister(t->pid); + kfree(t); + return -ENOMEM; + } + + return 0; +} + +/** @} */ +#endif /* _TRANSPORT_C_ */ |