This makes a very large difference to performance over the previous implementation. Note for the tests below I also applied the next commit changing the behaviour of the connections parameter. Using this test case: $ nbdkit -r -U - curl https://cloud-images.ubuntu.com/lunar/current/lunar-server-cloudimg-amd64... \ ipresolve=v4 --run 'nbdcopy -p $uri null' The times are as follows: multi, connections=0 19s (*) multi, connections=32 26s multi, connections=16 50s before this commit 2m46s (*) Not documented, but setting CURLMOPT_MAX_TOTAL_CONNECTIONS = 0 means allow unlimited connections. In practice the number of connections reaches 64. --- plugins/curl/curldefs.h | 35 +++- plugins/curl/config.c | 66 +----- plugins/curl/curl.c | 146 +++++++++----- plugins/curl/pool.c | 431 ++++++++++++++++++++++++++++++++-------- 4 files changed, 482 insertions(+), 196 deletions(-) diff --git a/plugins/curl/curldefs.h b/plugins/curl/curldefs.h index 9169b256d..db384f055 100644 --- a/plugins/curl/curldefs.h +++ b/plugins/curl/curldefs.h @@ -76,12 +76,6 @@ struct curl_handle { /* The underlying curl handle. */ CURL *c; - /* Index of this handle in the pool (for debugging). */ - size_t i; - - /* True if the handle is in use by a thread. */ - bool in_use; - /* These fields are used/initialized when we create the handle. */ bool accept_range; int64_t exportsize; @@ -100,6 +94,26 @@ struct curl_handle { /* Used by scripts.c */ struct curl_slist *headers_copy; + + /* Used by pool.c */ + struct command *cmd; +}; + +/* Asynchronous commands that can be sent to the pool thread. */ +enum command_type { GET_SIZE, PREAD, PWRITE, STOP }; +struct command { + /* These fields are set by the caller. */ + enum command_type type; /* command */ + void *ptr; /* for get_size, returned size */ + struct curl_handle *ch; /* for read/write, the easy handle */ + + /* This field is set to a unique value by send_command_and_wait. */ + uint64_t id; /* serial number */ + + /* These fields are used to signal back that the command finished. */ + pthread_mutex_t mutex; /* completion mutex */ + pthread_cond_t cond; /* completion condition */ + enum { SUBMITTED, SUCCEEDED, FAILED } status; }; /* config.c */ @@ -109,12 +123,13 @@ extern const char *curl_config_help; extern void unload_config (void); extern struct curl_handle *allocate_handle (void); extern void free_handle (struct curl_handle *); +extern int get_content_length_accept_range (struct curl_handle *ch); /* pool.c */ -extern void load_pool (void); -extern void unload_pool (void); -extern struct curl_handle *get_handle (void); -extern void put_handle (struct curl_handle *ch); +extern int curl_get_ready (void); +extern int curl_after_fork (void); +extern void curl_cleanup (void); +extern int send_command_and_wait (struct command *cmd); /* scripts.c */ extern int do_scripts (struct curl_handle *ch); diff --git a/plugins/curl/config.c b/plugins/curl/config.c index 742d60809..5cda46031 100644 --- a/plugins/curl/config.c +++ b/plugins/curl/config.c @@ -89,9 +89,6 @@ static const char *user_agent = NULL; static int debug_cb (CURL *handle, curl_infotype type, const char *data, size_t size, void *); -static size_t write_cb (char *ptr, size_t size, size_t nmemb, void *opaque); -static size_t read_cb (void *ptr, size_t size, size_t nmemb, void *opaque); -static int get_content_length_accept_range (struct curl_handle *ch); static bool try_fallback_GET_method (struct curl_handle *ch); static size_t header_cb (void *ptr, size_t size, size_t nmemb, void *opaque); static size_t error_cb (char *ptr, size_t size, size_t nmemb, void *opaque); @@ -668,17 +665,9 @@ allocate_handle (void) if (user_agent) curl_easy_setopt (ch->c, CURLOPT_USERAGENT, user_agent); - if (get_content_length_accept_range (ch) == -1) - goto err; - /* Get set up for reading and writing. */ curl_easy_setopt (ch->c, CURLOPT_HEADERFUNCTION, NULL); curl_easy_setopt (ch->c, CURLOPT_HEADERDATA, NULL); - curl_easy_setopt (ch->c, CURLOPT_WRITEFUNCTION, write_cb); - curl_easy_setopt (ch->c, CURLOPT_WRITEDATA, ch); - /* These are only used if !readonly but we always register them. */ - curl_easy_setopt (ch->c, CURLOPT_READFUNCTION, read_cb); - curl_easy_setopt (ch->c, CURLOPT_READDATA, ch); return ch; @@ -743,59 +732,10 @@ debug_cb (CURL *handle, curl_infotype type, return 0; } -/* NB: The terminology used by libcurl is confusing! - * - * WRITEFUNCTION / write_cb is used when reading from the remote server - * READFUNCTION / read_cb is used when writing to the remote server. - * - * We use the same terminology as libcurl here. - */ - -static size_t -write_cb (char *ptr, size_t size, size_t nmemb, void *opaque) -{ - struct curl_handle *ch = opaque; - size_t orig_realsize = size * nmemb; - size_t realsize = orig_realsize; - - assert (ch->write_buf); - - /* Don't read more than the requested amount of data, even if the - * server or libcurl sends more. - */ - if (realsize > ch->write_count) - realsize = ch->write_count; - - memcpy (ch->write_buf, ptr, realsize); - - ch->write_count -= realsize; - ch->write_buf += realsize; - - return orig_realsize; -} - -static size_t -read_cb (void *ptr, size_t size, size_t nmemb, void *opaque) -{ - struct curl_handle *ch = opaque; - size_t realsize = size * nmemb; - - assert (ch->read_buf); - if (realsize > ch->read_count) - realsize = ch->read_count; - - memcpy (ptr, ch->read_buf, realsize); - - ch->read_count -= realsize; - ch->read_buf += realsize; - - return realsize; -} - /* Get the file size and also whether the remote HTTP server * supports byte ranges. */ -static int +int get_content_length_accept_range (struct curl_handle *ch) { CURLcode r; @@ -821,6 +761,10 @@ get_content_length_accept_range (struct curl_handle *ch) curl_easy_setopt (ch->c, CURLOPT_NOBODY, 1L); curl_easy_setopt (ch->c, CURLOPT_HEADERFUNCTION, header_cb); curl_easy_setopt (ch->c, CURLOPT_HEADERDATA, ch); + curl_easy_setopt (ch->c, CURLOPT_WRITEFUNCTION, NULL); + curl_easy_setopt (ch->c, CURLOPT_WRITEDATA, NULL); + curl_easy_setopt (ch->c, CURLOPT_READFUNCTION, NULL); + curl_easy_setopt (ch->c, CURLOPT_READDATA, NULL); r = curl_easy_perform (ch->c); update_times (ch->c); if (r != CURLE_OK) { diff --git a/plugins/curl/curl.c b/plugins/curl/curl.c index 99a7e00b5..c29b5d0cb 100644 --- a/plugins/curl/curl.c +++ b/plugins/curl/curl.c @@ -48,8 +48,6 @@ #include <nbdkit-plugin.h> -#include "cleanup.h" - #include "curldefs.h" const char *cookie_script = NULL; @@ -67,8 +65,6 @@ curl_load (void) nbdkit_error ("libcurl initialization failed: %d", (int) r); exit (EXIT_FAILURE); } - - load_pool (); } static void @@ -76,7 +72,6 @@ curl_unload (void) { unload_config (); scripts_unload (); - unload_pool (); display_times (); curl_global_cleanup (); } @@ -108,30 +103,17 @@ curl_close (void *handle) #define THREAD_MODEL NBDKIT_THREAD_MODEL_PARALLEL -/* Calls get_handle() ... put_handle() to get a handle for the length - * of the current scope. - */ -#define GET_HANDLE_FOR_CURRENT_SCOPE(ch) \ - CLEANUP_PUT_HANDLE struct curl_handle *ch = get_handle (); -#define CLEANUP_PUT_HANDLE __attribute__ ((cleanup (cleanup_put_handle))) -static void -cleanup_put_handle (void *chp) -{ - struct curl_handle *ch = * (struct curl_handle **) chp; - - if (ch != NULL) - put_handle (ch); -} - /* Get the file size. */ static int64_t curl_get_size (void *handle) { - GET_HANDLE_FOR_CURRENT_SCOPE (ch); - if (ch == NULL) + int64_t size; + struct command cmd = { .type = GET_SIZE, .ptr = &size }; + + if (send_command_and_wait (&cmd) == -1) return -1; - return ch->exportsize; + return size; } /* Multi-conn is safe for read-only connections, but HTTP does not @@ -146,23 +128,56 @@ curl_can_multi_conn (void *handle) return !! h->readonly; } +/* NB: The terminology used by libcurl is confusing! + * + * WRITEFUNCTION / write_cb is used when reading from the remote server + * READFUNCTION / read_cb is used when writing to the remote server. + * + * We use the same terminology as libcurl here. + */ + +static size_t +write_cb (char *ptr, size_t size, size_t nmemb, void *opaque) +{ + struct curl_handle *ch = opaque; + size_t orig_realsize = size * nmemb; + size_t realsize = orig_realsize; + + assert (ch->write_buf); + + /* Don't read more than the requested amount of data, even if the + * server or libcurl sends more. + */ + if (realsize > ch->write_count) + realsize = ch->write_count; + + memcpy (ch->write_buf, ptr, realsize); + + ch->write_count -= realsize; + ch->write_buf += realsize; + + return orig_realsize; +} + /* Read data from the remote server. */ static int curl_pread (void *handle, void *buf, uint32_t count, uint64_t offset) { - CURLcode r; + struct curl_handle *ch; char range[128]; - GET_HANDLE_FOR_CURRENT_SCOPE (ch); - if (ch == NULL) - return -1; + /* Get a curl easy handle. */ + ch = allocate_handle (); + if (ch == NULL) goto err; /* Run the scripts if necessary and set headers in the handle. */ - if (do_scripts (ch) == -1) return -1; + if (do_scripts (ch) == -1) goto err; /* Tell the write_cb where we want the data to be written. write_cb * will update this if the data comes in multiple sections. */ + curl_easy_setopt (ch->c, CURLOPT_WRITEFUNCTION, write_cb); + curl_easy_setopt (ch->c, CURLOPT_WRITEDATA, ch); ch->write_buf = buf; ch->write_count = count; @@ -173,12 +188,14 @@ curl_pread (void *handle, void *buf, uint32_t count, uint64_t offset) offset, offset + count); curl_easy_setopt (ch->c, CURLOPT_RANGE, range); - /* The assumption here is that curl will look after timeouts. */ - r = curl_easy_perform (ch->c); - if (r != CURLE_OK) { - display_curl_error (ch, r, "pread: curl_easy_perform"); - return -1; - } + /* Send the command to the worker thread and wait. */ + struct command cmd = { + .type = PREAD, + .ch = ch, + }; + + if (send_command_and_wait (&cmd) == -1) + goto err; update_times (ch->c); /* Could use curl_easy_getinfo here to obtain further information @@ -188,42 +205,70 @@ curl_pread (void *handle, void *buf, uint32_t count, uint64_t offset) /* As far as I understand the cURL API, this should never happen. */ assert (ch->write_count == 0); + free_handle (ch); return 0; + + err: + if (ch) + free_handle (ch); + return -1; +} + +static size_t +read_cb (void *ptr, size_t size, size_t nmemb, void *opaque) +{ + struct curl_handle *ch = opaque; + size_t realsize = size * nmemb; + + assert (ch->read_buf); + if (realsize > ch->read_count) + realsize = ch->read_count; + + memcpy (ptr, ch->read_buf, realsize); + + ch->read_count -= realsize; + ch->read_buf += realsize; + + return realsize; } /* Write data to the remote server. */ static int curl_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) { - CURLcode r; + struct curl_handle *ch; char range[128]; - GET_HANDLE_FOR_CURRENT_SCOPE (ch); - if (ch == NULL) - return -1; + /* Get a curl easy handle. */ + ch = allocate_handle (); + if (ch == NULL) goto err; /* Run the scripts if necessary and set headers in the handle. */ - if (do_scripts (ch) == -1) return -1; + if (do_scripts (ch) == -1) goto err; /* Tell the read_cb where we want the data to be read from. read_cb * will update this if the data comes in multiple sections. */ + curl_easy_setopt (ch->c, CURLOPT_READFUNCTION, read_cb); + curl_easy_setopt (ch->c, CURLOPT_READDATA, ch); ch->read_buf = buf; ch->read_count = count; - curl_easy_setopt (ch->c, CURLOPT_UPLOAD, 1L); + curl_easy_setopt (ch->c, CURLOPT_HTTPGET, 1L); /* Make an HTTP range request. */ snprintf (range, sizeof range, "%" PRIu64 "-%" PRIu64, offset, offset + count); curl_easy_setopt (ch->c, CURLOPT_RANGE, range); - /* The assumption here is that curl will look after timeouts. */ - r = curl_easy_perform (ch->c); - if (r != CURLE_OK) { - display_curl_error (ch, r, "pwrite: curl_easy_perform"); - return -1; - } + /* Send the command to the worker thread and wait. */ + struct command cmd = { + .type = PWRITE, + .ch = ch, + }; + + if (send_command_and_wait (&cmd) == -1) + goto err; update_times (ch->c); /* Could use curl_easy_getinfo here to obtain further information @@ -233,7 +278,13 @@ curl_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset) /* As far as I understand the cURL API, this should never happen. */ assert (ch->read_count == 0); + free_handle (ch); return 0; + + err: + if (ch) + free_handle (ch); + return -1; } static struct nbdkit_plugin plugin = { @@ -249,6 +300,9 @@ static struct nbdkit_plugin plugin = { */ //.config_help = curl_config_help, .magic_config_key = "url", + .get_ready = curl_get_ready, + .after_fork = curl_after_fork, + .cleanup = curl_cleanup, .open = curl_open, .close = curl_close, .get_size = curl_get_size, diff --git a/plugins/curl/pool.c b/plugins/curl/pool.c index 91e56f070..2835f1664 100644 --- a/plugins/curl/pool.c +++ b/plugins/curl/pool.c @@ -30,11 +30,29 @@ * SUCH DAMAGE. */ -/* Curl handle pool. +/* Worker thread which processes the curl multi interface. * - * To get a libcurl handle, call get_handle(). When you hold the - * handle, it is yours exclusively to use. After you have finished - * with the handle, put it back into the pool by calling put_handle(). + * The main nbdkit threads (see curl.c) create curl easy handles + * initialized with the work they want to carry out. Note there is + * one easy handle per task (eg. per pread/pwrite request). The easy + * handles are not reused. + * + * The commands + optional easy handle are submitted to the worker + * thread over a self-pipe (it's easy to use a pipe here because the + * way curl multi works is it can listen on an extra fd, but not on + * anything else like a pthread condition). The curl multi performs + * the work of the outstanding easy handles. + * + * When an easy handle finishes work or errors, we retire the command + * by signalling back to the waiting nbdkit thread using a pthread + * condition. + * + * In my experiments, we're almost always I/O bound so I haven't seen + * any strong need to use more than one curl multi / worker thread, + * although it would be possible to add more in future. + * + * See also this extremely useful thread: + * https://curl.se/mail/lib-2019-03/0100.html */ #include <config.h> @@ -45,9 +63,19 @@ #include <stdint.h> #include <inttypes.h> #include <string.h> +#include <unistd.h> #include <assert.h> #include <pthread.h> +#ifdef HAVE_STDATOMIC_H +#include <stdatomic.h> +#else +/* Some old platforms lack atomic types, but 32 bit ints are usually + * "atomic enough". + */ +#define _Atomic /**/ +#endif + #include <curl/curl.h> #include <nbdkit-plugin.h> @@ -62,109 +90,354 @@ NBDKIT_DLL_PUBLIC int curl_debug_pool = 0; unsigned connections = 4; -/* This lock protects access to the curl_handles vector below. */ -static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER; +/* Pipe used to notify background thread that a command is pending in + * the queue. A pointer to the 'struct command' is sent over the + * pipe. + */ +static int self_pipe[2] = { -1, -1 }; -/* List of curl handles. This is allocated dynamically as more - * handles are requested. Currently it does not shrink. It may grow - * up to 'connections' in length. +/* The curl multi handle. */ +static CURLM *multi; + +/* List of running easy handles. We only need to maintain this so we + * can remove them from the multi handle when cleaning up. */ DEFINE_VECTOR_TYPE (curl_handle_list, struct curl_handle *); static curl_handle_list curl_handles = empty_vector; -/* The condition is used when the curl handles vector is full and - * we're waiting for a thread to put_handle. - */ -static pthread_cond_t cond = PTHREAD_COND_INITIALIZER; -static size_t in_use = 0, waiting = 0; +static const char * +command_type_to_string (enum command_type type) +{ + switch (type) { + case GET_SIZE: return "GET_SIZE"; + case PREAD: return "PREAD"; + case PWRITE: return "PWRITE"; + case STOP: return "STOP"; + default: abort (); + } +} -/* Initialize pool structures. */ -void -load_pool (void) +int +curl_get_ready (void) +{ + multi = curl_multi_init (); + if (multi == NULL) { + nbdkit_error ("curl_multi_init failed: %m"); + return -1; + } + + return 0; +} + +/* Start and stop the background thread. */ +static pthread_t thread; +static bool thread_running; +static void *pool_worker (void *); + +int +curl_after_fork (void) { + int err; + + if (pipe (self_pipe) == -1) { + nbdkit_error ("pipe: %m"); + return -1; + } + + /* Start the pool background thread where all the curl work is done. */ + err = pthread_create (&thread, NULL, pool_worker, NULL); + if (err != 0) { + errno = err; + nbdkit_error ("pthread_create: %m"); + return -1; + } + thread_running = true; + + return 0; } -/* Close and free all handles in the pool. */ +/* Unload the background thread. */ void -unload_pool (void) +curl_cleanup (void) { - size_t i; + if (thread_running) { + /* Stop the background thread. */ + struct command cmd = { .type = STOP }; + send_command_and_wait (&cmd); + pthread_join (thread, NULL); + thread_running = false; + } - if (curl_debug_pool) - nbdkit_debug ("unload_pool: number of curl handles allocated: %zu", - curl_handles.len); + if (self_pipe[0] >= 0) { + close (self_pipe[0]); + self_pipe[0] = -1; + } + if (self_pipe[1] >= 0) { + close (self_pipe[1]); + self_pipe[1] = -1; + } - for (i = 0; i < curl_handles.len; ++i) - free_handle (curl_handles.ptr[i]); - curl_handle_list_reset (&curl_handles); + if (multi) { + size_t i; + + /* Remove and free any easy handles in the multi. */ + for (i = 0; i < curl_handles.len; ++i) { + curl_multi_remove_handle (multi, curl_handles.ptr[i]->c); + free_handle (curl_handles.ptr[i]); + } + + curl_multi_cleanup (multi); + multi = NULL; + } } -/* Get a handle from the pool. +/* Command queue. */ +static _Atomic uint64_t id; /* next command ID */ + +/* Send command to the background thread and wait for completion. + * This is only called by one of the nbdkit threads. * - * It is owned exclusively by the caller until they call put_handle. + * Returns 0 for OK + * On error, calls nbdkit_error and returns -1. */ -struct curl_handle * -get_handle (void) +int +send_command_and_wait (struct command *cmd) { - ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); - size_t i; - struct curl_handle *ch; - - again: - /* Look for a handle which is not in_use. */ - for (i = 0; i < curl_handles.len; ++i) { - ch = curl_handles.ptr[i]; - if (!ch->in_use) { - ch->in_use = true; - in_use++; + cmd->id = id++; + + /* This will be used to signal command completion back to us. */ + pthread_mutex_init (&cmd->mutex, NULL); + pthread_cond_init (&cmd->cond, NULL); + + /* Send the command to the background thread. */ + if (write (self_pipe[1], &cmd, sizeof cmd) != sizeof cmd) + abort (); + + /* Wait for the command to be completed by the background thread. */ + { + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&cmd->mutex); + while (cmd->status == SUBMITTED) + pthread_cond_wait (&cmd->cond, &cmd->mutex); + } + + pthread_mutex_destroy (&cmd->mutex); + pthread_cond_destroy (&cmd->cond); + + /* On error the background thread will call nbdkit_error. */ + switch (cmd->status) { + case SUCCEEDED: return 0; + case FAILED: return -1; + default: abort (); + } +} + +/* The background thread. */ +static void check_for_finished_handles (void); +static void retire_command (struct command *cmd, int status); +static void do_get_size (struct command *cmd); +static void do_pread (struct command *cmd); +static void do_pwrite (struct command *cmd); + +static void * +pool_worker (void *vp) +{ + bool stop = false; + + if (curl_debug_pool) + nbdkit_debug ("curl: background thread started"); + + while (!stop) { + struct command *cmd = NULL; + struct curl_waitfd extra_fds[1] = + { { .fd = self_pipe[0], .events = CURL_WAIT_POLLIN } }; + CURLMcode mc; + int numfds, running_handles, repeats = 0; + + do { + /* Process the multi handle. */ + mc = curl_multi_perform (multi, &running_handles); + if (mc != CURLM_OK) { + nbdkit_error ("curl_multi_perform: %s", curl_multi_strerror (mc)); + abort (); /* XXX We don't expect this to happen */ + } + + check_for_finished_handles (); + + mc = curl_multi_wait (multi, extra_fds, 1, 1000000, &numfds); + if (mc != CURLM_OK) { + nbdkit_error ("curl_multi_wait: %s", curl_multi_strerror (mc)); + abort (); /* XXX We don't expect this to happen */ + } + if (curl_debug_pool) - nbdkit_debug ("get_handle: %zu", ch->i); - return ch; - } - } + nbdkit_debug ("curl_multi_wait returned: running_handles=%d numfds=%d", + running_handles, numfds); + + if (numfds == 0) { + repeats++; + if (repeats > 1) + nbdkit_nanosleep (1, 0); + } + else { + repeats = 0; + if (extra_fds[0].revents == CURL_WAIT_POLLIN) { + /* There's a command waiting. */ + if (read (self_pipe[0], &cmd, sizeof cmd) != sizeof cmd) + abort (); + } + } + } while (!cmd); - /* If more connections are allowed, then allocate a new handle. */ - if (curl_handles.len < connections) { - ch = allocate_handle (); - if (ch == NULL) - return NULL; - if (curl_handle_list_append (&curl_handles, ch) == -1) { - free_handle (ch); - return NULL; - } - ch->i = curl_handles.len - 1; - ch->in_use = true; - in_use++; if (curl_debug_pool) - nbdkit_debug ("get_handle: %zu", ch->i); - return ch; - } + nbdkit_debug ("curl: dispatching %s command %" PRIu64, + command_type_to_string (cmd->type), cmd->id); + + switch (cmd->type) { + case STOP: + stop = true; + retire_command (cmd, SUCCEEDED); + break; + + case GET_SIZE: + do_get_size (cmd); + break; + + case PREAD: + do_pread (cmd); + break; + + case PWRITE: + do_pwrite (cmd); + break; + } + } /* while (!stop) */ - /* Otherwise we have run out of connections so we must wait until - * another thread calls put_handle. - */ - assert (in_use == connections); - waiting++; - while (in_use == connections) - pthread_cond_wait (&cond, &lock); - waiting--; + if (curl_debug_pool) + nbdkit_debug ("curl: background thread stopped"); - goto again; + return NULL; } -/* Return the handle to the pool. */ -void -put_handle (struct curl_handle *ch) +/* This checks if any easy handles in the multi have + * finished and retires the associated commands. + */ +static void +check_for_finished_handles (void) { - ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&lock); + CURLMsg *msg; + int msgs_in_queue; + + while ((msg = curl_multi_info_read (multi, &msgs_in_queue)) != NULL) { + size_t i; + struct curl_handle *ch = NULL; + + if (msg->msg == CURLMSG_DONE) { + /* Find this curl_handle. */ + for (i = 0; i < curl_handles.len; ++i) { + if (curl_handles.ptr[i]->c == msg->easy_handle) { + ch = curl_handles.ptr[i]; + curl_handle_list_remove (&curl_handles, i); + } + } + if (ch == NULL) abort (); + + if (msg->data.result != CURLE_OK) + display_curl_error (ch, msg->data.result, "curl"); + + curl_multi_remove_handle (multi, ch->c); + retire_command (ch->cmd, + msg->data.result == CURLE_OK ? SUCCEEDED : FAILED); + } + } +} + +/* Retire a command. status is SUCCEEDED | FAILED */ +static void +retire_command (struct command *cmd, int status) +{ if (curl_debug_pool) - nbdkit_debug ("put_handle: %zu", ch->i); + nbdkit_debug ("curl: retiring %s command %" PRIu64, + command_type_to_string (cmd->type), cmd->id); + + ACQUIRE_LOCK_FOR_CURRENT_SCOPE (&cmd->mutex); + cmd->status = status; + pthread_cond_signal (&cmd->cond); +} + +/* We handle get_size synchronously, the first time we are called. + * We assume the size never changes (you must restart nbdkit). + */ +static struct curl_handle *get_size_ch; + +static void +do_get_size (struct command *cmd) +{ + int64_t size; + + if (get_size_ch == NULL) { + get_size_ch = allocate_handle (); + if (get_size_ch == NULL) + goto err; + + if (get_content_length_accept_range (get_size_ch) == -1) { + free_handle (get_size_ch); + get_size_ch = NULL; + goto err; + } + } + + size = get_size_ch->exportsize; + if (size == -1) + goto err; + * (int64_t *) cmd->ptr = size; + retire_command (cmd, SUCCEEDED); + return; + +err: + retire_command (cmd, FAILED); +} + +static void +do_pread (struct command *cmd) +{ + CURLMcode mc; + + cmd->ch->cmd = cmd; + + /* Add the handle to the multi. */ + mc = curl_multi_add_handle (multi, cmd->ch->c); + if (mc != CURLM_OK) { + nbdkit_error ("curl_multi_add_handle: %s", curl_multi_strerror (mc)); + goto err; + } + + if (curl_handle_list_append (&curl_handles, cmd->ch) == -1) + goto err; + return; + + err: + retire_command (cmd, FAILED); +} + +static void +do_pwrite (struct command *cmd) +{ + CURLMcode mc; + + cmd->ch->cmd = cmd; + + /* Add the handle to the multi. */ + mc = curl_multi_add_handle (multi, cmd->ch->c); + if (mc != CURLM_OK) { + nbdkit_error ("curl_multi_add_handle: %s", curl_multi_strerror (mc)); + goto err; + } - ch->in_use = false; - in_use--; + if (curl_handle_list_append (&curl_handles, cmd->ch) == -1) + goto err; + return; - /* Signal the next thread which is waiting. */ - if (waiting > 0) - pthread_cond_signal (&cond); + err: + retire_command (cmd, FAILED); } -- 2.41.0