diff options
| -rw-r--r-- | Documentation/technical/api-sub-process.txt | 59 | ||||
| -rw-r--r-- | Makefile | 1 | ||||
| -rw-r--r-- | convert.c | 161 | ||||
| -rw-r--r-- | pkt-line.c | 33 | ||||
| -rw-r--r-- | pkt-line.h | 13 | ||||
| -rw-r--r-- | sub-process.c | 106 | ||||
| -rw-r--r-- | sub-process.h | 49 |
7 files changed, 293 insertions, 129 deletions
diff --git a/Documentation/technical/api-sub-process.txt b/Documentation/technical/api-sub-process.txt new file mode 100644 index 0000000000..793508cf3e --- /dev/null +++ b/Documentation/technical/api-sub-process.txt @@ -0,0 +1,59 @@ +sub-process API +=============== + +The sub-process API makes it possible to run background sub-processes +for the entire lifetime of a Git invocation. If Git needs to communicate +with an external process multiple times, then this can reduces the process +invocation overhead. Git and the sub-process communicate through stdin and +stdout. + +The sub-processes are kept in a hashmap by command name and looked up +via the subprocess_find_entry function. If an existing instance can not +be found then a new process should be created and started. When the +parent git command terminates, all sub-processes are also terminated. + +This API is based on the run-command API. + +Data structures +--------------- + +* `struct subprocess_entry` + +The sub-process structure. Members should not be accessed directly. + +Types +----- + +'int(*subprocess_start_fn)(struct subprocess_entry *entry)':: + + User-supplied function to initialize the sub-process. This is + typically used to negotiate the interface version and capabilities. + + +Functions +--------- + +`cmd2process_cmp`:: + + Function to test two subprocess hashmap entries for equality. + +`subprocess_start`:: + + Start a subprocess and add it to the subprocess hashmap. + +`subprocess_stop`:: + + Kill a subprocess and remove it from the subprocess hashmap. + +`subprocess_find_entry`:: + + Find a subprocess in the subprocess hashmap. + +`subprocess_get_child_process`:: + + Get the underlying `struct child_process` from a subprocess. + +`subprocess_read_status`:: + + Helper function to read packets looking for the last "status=<foo>" + key/value pair. @@ -842,6 +842,7 @@ LIB_OBJS += streaming.o LIB_OBJS += string-list.o LIB_OBJS += submodule.o LIB_OBJS += submodule-config.o +LIB_OBJS += sub-process.o LIB_OBJS += symlinks.o LIB_OBJS += tag.o LIB_OBJS += tempfile.o @@ -4,6 +4,7 @@ #include "quote.h" #include "sigchain.h" #include "pkt-line.h" +#include "sub-process.h" /* * convert.c - convert a file when checking it out and checking it in. @@ -497,126 +498,26 @@ static int apply_single_file_filter(const char *path, const char *src, size_t le #define CAP_SMUDGE (1u<<1) struct cmd2process { - struct hashmap_entry ent; /* must be the first member! */ + struct subprocess_entry subprocess; /* must be the first member! */ unsigned int supported_capabilities; - const char *cmd; - struct child_process process; }; -static int cmd_process_map_initialized; -static struct hashmap cmd_process_map; - -static int cmd2process_cmp(const struct cmd2process *e1, - const struct cmd2process *e2, - const void *unused) -{ - return strcmp(e1->cmd, e2->cmd); -} - -static struct cmd2process *find_multi_file_filter_entry(struct hashmap *hashmap, const char *cmd) -{ - struct cmd2process key; - hashmap_entry_init(&key, strhash(cmd)); - key.cmd = cmd; - return hashmap_get(hashmap, &key, NULL); -} +static int subprocess_map_initialized; +static struct hashmap subprocess_map; -static int packet_write_list(int fd, const char *line, ...) +static int start_multi_file_filter_fn(struct subprocess_entry *subprocess) { - va_list args; int err; - va_start(args, line); - for (;;) { - if (!line) - break; - if (strlen(line) > LARGE_PACKET_DATA_MAX) - return -1; - err = packet_write_fmt_gently(fd, "%s\n", line); - if (err) - return err; - line = va_arg(args, const char*); - } - va_end(args); - return packet_flush_gently(fd); -} - -static void read_multi_file_filter_status(int fd, struct strbuf *status) -{ - struct strbuf **pair; - char *line; - for (;;) { - line = packet_read_line(fd, NULL); - if (!line) - break; - pair = strbuf_split_str(line, '=', 2); - if (pair[0] && pair[0]->len && pair[1]) { - /* the last "status=<foo>" line wins */ - if (!strcmp(pair[0]->buf, "status=")) { - strbuf_reset(status); - strbuf_addbuf(status, pair[1]); - } - } - strbuf_list_free(pair); - } -} - -static void kill_multi_file_filter(struct hashmap *hashmap, struct cmd2process *entry) -{ - if (!entry) - return; - - entry->process.clean_on_exit = 0; - kill(entry->process.pid, SIGTERM); - finish_command(&entry->process); - - hashmap_remove(hashmap, entry, NULL); - free(entry); -} - -static void stop_multi_file_filter(struct child_process *process) -{ - sigchain_push(SIGPIPE, SIG_IGN); - /* Closing the pipe signals the filter to initiate a shutdown. */ - close(process->in); - close(process->out); - sigchain_pop(SIGPIPE); - /* Finish command will wait until the shutdown is complete. */ - finish_command(process); -} - -static struct cmd2process *start_multi_file_filter(struct hashmap *hashmap, const char *cmd) -{ - int err; - struct cmd2process *entry; - struct child_process *process; - const char *argv[] = { cmd, NULL }; + struct cmd2process *entry = (struct cmd2process *)subprocess; struct string_list cap_list = STRING_LIST_INIT_NODUP; char *cap_buf; const char *cap_name; - - entry = xmalloc(sizeof(*entry)); - entry->cmd = cmd; - entry->supported_capabilities = 0; - process = &entry->process; - - child_process_init(process); - process->argv = argv; - process->use_shell = 1; - process->in = -1; - process->out = -1; - process->clean_on_exit = 1; - process->clean_on_exit_handler = stop_multi_file_filter; - - if (start_command(process)) { - error("cannot fork to run external filter '%s'", cmd); - return NULL; - } - - hashmap_entry_init(entry, strhash(cmd)); + struct child_process *process = &subprocess->process; + const char *cmd = subprocess->cmd; sigchain_push(SIGPIPE, SIG_IGN); - err = packet_write_list(process->in, "git-filter-client", "version=2", NULL); + err = packet_writel(process->in, "git-filter-client", "version=2", NULL); if (err) goto done; @@ -632,7 +533,7 @@ static struct cmd2process *start_multi_file_filter(struct hashmap *hashmap, cons if (err) goto done; - err = packet_write_list(process->in, "capability=clean", "capability=smudge", NULL); + err = packet_writel(process->in, "capability=clean", "capability=smudge", NULL); for (;;) { cap_buf = packet_read_line(process->out, NULL); @@ -661,14 +562,7 @@ static struct cmd2process *start_multi_file_filter(struct hashmap *hashmap, cons done: sigchain_pop(SIGPIPE); - if (err || errno == EPIPE) { - error("initialization for external filter '%s' failed", cmd); - kill_multi_file_filter(hashmap, entry); - return NULL; - } - - hashmap_add(hashmap, entry); - return entry; + return err; } static int apply_multi_file_filter(const char *path, const char *src, size_t len, @@ -682,22 +576,26 @@ static int apply_multi_file_filter(const char *path, const char *src, size_t len struct strbuf filter_status = STRBUF_INIT; const char *filter_type; - if (!cmd_process_map_initialized) { - cmd_process_map_initialized = 1; - hashmap_init(&cmd_process_map, (hashmap_cmp_fn) cmd2process_cmp, 0); + if (!subprocess_map_initialized) { + subprocess_map_initialized = 1; + hashmap_init(&subprocess_map, (hashmap_cmp_fn) cmd2process_cmp, 0); entry = NULL; } else { - entry = find_multi_file_filter_entry(&cmd_process_map, cmd); + entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd); } fflush(NULL); if (!entry) { - entry = start_multi_file_filter(&cmd_process_map, cmd); - if (!entry) + entry = xmalloc(sizeof(*entry)); + entry->supported_capabilities = 0; + + if (subprocess_start(&subprocess_map, &entry->subprocess, cmd, start_multi_file_filter_fn)) { + free(entry); return 0; + } } - process = &entry->process; + process = &entry->subprocess.process; if (!(wanted_capability & entry->supported_capabilities)) return 0; @@ -737,7 +635,10 @@ static int apply_multi_file_filter(const char *path, const char *src, size_t len if (err) goto done; - read_multi_file_filter_status(process->out, &filter_status); + err = subprocess_read_status(process->out, &filter_status); + if (err) + goto done; + err = strcmp(filter_status.buf, "success"); if (err) goto done; @@ -746,13 +647,16 @@ static int apply_multi_file_filter(const char *path, const char *src, size_t len if (err) goto done; - read_multi_file_filter_status(process->out, &filter_status); + err = subprocess_read_status(process->out, &filter_status); + if (err) + goto done; + err = strcmp(filter_status.buf, "success"); done: sigchain_pop(SIGPIPE); - if (err || errno == EPIPE) { + if (err) { if (!strcmp(filter_status.buf, "error")) { /* The filter signaled a problem with the file. */ } else if (!strcmp(filter_status.buf, "abort")) { @@ -768,7 +672,8 @@ done: * Force shutdown and restart if another blob requires filtering. */ error("external filter '%s' failed", cmd); - kill_multi_file_filter(&cmd_process_map, entry); + subprocess_stop(&subprocess_map, &entry->subprocess); + free(entry); } } else { strbuf_swap(dst, &nbuf); diff --git a/pkt-line.c b/pkt-line.c index d4b6bfe076..9d845ecc3c 100644 --- a/pkt-line.c +++ b/pkt-line.c @@ -171,6 +171,25 @@ int packet_write_fmt_gently(int fd, const char *fmt, ...) return status; } +int packet_writel(int fd, const char *line, ...) +{ + va_list args; + int err; + va_start(args, line); + for (;;) { + if (!line) + break; + if (strlen(line) > LARGE_PACKET_DATA_MAX) + return -1; + err = packet_write_fmt_gently(fd, "%s\n", line); + if (err) + return err; + line = va_arg(args, const char*); + } + va_end(args); + return packet_flush_gently(fd); +} + static int packet_write_gently(const int fd_out, const char *buf, size_t size) { static char packet_write_buffer[LARGE_PACKET_MAX]; @@ -315,7 +334,7 @@ static char *packet_read_line_generic(int fd, PACKET_READ_CHOMP_NEWLINE); if (dst_len) *dst_len = len; - return len ? packet_buffer : NULL; + return (len > 0) ? packet_buffer : NULL; } char *packet_read_line(int fd, int *len_p) @@ -323,6 +342,18 @@ char *packet_read_line(int fd, int *len_p) return packet_read_line_generic(fd, NULL, NULL, len_p); } +int packet_read_line_gently(int fd, int *dst_len, char **dst_line) +{ + int len = packet_read(fd, NULL, NULL, + packet_buffer, sizeof(packet_buffer), + PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF); + if (dst_len) + *dst_len = len; + if (dst_line) + *dst_line = (len > 0) ? packet_buffer : NULL; + return len; +} + char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len) { return packet_read_line_generic(-1, src, src_len, dst_len); diff --git a/pkt-line.h b/pkt-line.h index 18eac64830..450183b649 100644 --- a/pkt-line.h +++ b/pkt-line.h @@ -25,6 +25,8 @@ void packet_buf_flush(struct strbuf *buf); void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3))); int packet_flush_gently(int fd); int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3))); +LAST_ARG_MUST_BE_NULL +int packet_writel(int fd, const char *line, ...); int write_packetized_from_fd(int fd_in, int fd_out); int write_packetized_from_buf(const char *src_in, size_t len, int fd_out); @@ -74,6 +76,17 @@ int packet_read(int fd, char **src_buffer, size_t *src_len, char char *packet_read_line(int fd, int *size); /* + * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF + * and CHOMP_NEWLINE options. The return value specifies the number of bytes + * read into the buffer or -1 on truncated input. If the *dst_line parameter + * is not NULL it will return NULL for a flush packet or when the number of + * bytes copied is zero and otherwise points to a static buffer (that may be + * overwritten by subsequent calls). If the size parameter is not NULL, the + * length of the packet is written to it. + */ +int packet_read_line_gently(int fd, int *size, char **dst_line); + +/* * Same as packet_read_line, but read from a buf rather than a descriptor; * see packet_read for details on how src_* is used. */ diff --git a/sub-process.c b/sub-process.c new file mode 100644 index 0000000000..92f8aea70a --- /dev/null +++ b/sub-process.c @@ -0,0 +1,106 @@ +/* + * Generic implementation of background process infrastructure. + */ +#include "sub-process.h" +#include "sigchain.h" +#include "pkt-line.h" + +int cmd2process_cmp(const struct subprocess_entry *e1, + const struct subprocess_entry *e2, + const void *unused) +{ + return strcmp(e1->cmd, e2->cmd); +} + +struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd) +{ + struct subprocess_entry key; + + hashmap_entry_init(&key, strhash(cmd)); + key.cmd = cmd; + return hashmap_get(hashmap, &key, NULL); +} + +int subprocess_read_status(int fd, struct strbuf *status) +{ + struct strbuf **pair; + char *line; + int len; + + for (;;) { + len = packet_read_line_gently(fd, NULL, &line); + if ((len < 0) || !line) + break; + pair = strbuf_split_str(line, '=', 2); + if (pair[0] && pair[0]->len && pair[1]) { + /* the last "status=<foo>" line wins */ + if (!strcmp(pair[0]->buf, "status=")) { + strbuf_reset(status); + strbuf_addbuf(status, pair[1]); + } + } + strbuf_list_free(pair); + } + + return (len < 0) ? len : 0; +} + +void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry) +{ + if (!entry) + return; + + entry->process.clean_on_exit = 0; + kill(entry->process.pid, SIGTERM); + finish_command(&entry->process); + + hashmap_remove(hashmap, entry, NULL); +} + +static void subprocess_exit_handler(struct child_process *process) +{ + sigchain_push(SIGPIPE, SIG_IGN); + /* Closing the pipe signals the subprocess to initiate a shutdown. */ + close(process->in); + close(process->out); + sigchain_pop(SIGPIPE); + /* Finish command will wait until the shutdown is complete. */ + finish_command(process); +} + +int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd, + subprocess_start_fn startfn) +{ + int err; + struct child_process *process; + const char *argv[] = { cmd, NULL }; + + entry->cmd = cmd; + process = &entry->process; + + child_process_init(process); + process->argv = argv; + process->use_shell = 1; + process->in = -1; + process->out = -1; + process->clean_on_exit = 1; + process->clean_on_exit_handler = subprocess_exit_handler; + + err = start_command(process); + if (err) { + error("cannot fork to run subprocess '%s'", cmd); + return err; + } + + hashmap_entry_init(entry, strhash(cmd)); + + err = startfn(entry); + if (err) { + error("initialization for subprocess '%s' failed", cmd); + subprocess_stop(hashmap, entry); + return err; + } + + hashmap_add(hashmap, entry); + return 0; +} diff --git a/sub-process.h b/sub-process.h new file mode 100644 index 0000000000..7d451e1cde --- /dev/null +++ b/sub-process.h @@ -0,0 +1,49 @@ +#ifndef SUBPROCESS_H +#define SUBPROCESS_H + +#include "git-compat-util.h" +#include "hashmap.h" +#include "run-command.h" + +/* + * Generic implementation of background process infrastructure. + * See Documentation/technical/api-background-process.txt. + */ + + /* data structures */ + +struct subprocess_entry { + struct hashmap_entry ent; /* must be the first member! */ + const char *cmd; + struct child_process process; +}; + +/* subprocess functions */ + +int cmd2process_cmp(const struct subprocess_entry *e1, + const struct subprocess_entry *e2, const void *unused); + +typedef int(*subprocess_start_fn)(struct subprocess_entry *entry); +int subprocess_start(struct hashmap *hashmap, struct subprocess_entry *entry, const char *cmd, + subprocess_start_fn startfn); + +void subprocess_stop(struct hashmap *hashmap, struct subprocess_entry *entry); + +struct subprocess_entry *subprocess_find_entry(struct hashmap *hashmap, const char *cmd); + +/* subprocess helper functions */ + +static inline struct child_process *subprocess_get_child_process( + struct subprocess_entry *entry) +{ + return &entry->process; +} + +/* + * Helper function that will read packets looking for "status=<foo>" + * key/value pairs and return the value from the last "status" packet + */ + +int subprocess_read_status(int fd, struct strbuf *status); + +#endif |