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cmd: add a way to run (and wait) asynchronously commands

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This commit is contained in:
Pino Toscano
2015-02-02 15:44:37 +01:00
committed by Richard W.M. Jones
parent 4bb3c44a28
commit c5d3d198dc
2 changed files with 58 additions and 9 deletions
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64
src/command.c
View File

@@ -360,7 +360,7 @@ debug_command (struct command *cmd)
}
static int
run_command (struct command *cmd)
run_command (struct command *cmd, bool get_stdout_fd, bool get_stderr_fd)
{
struct sigaction sa;
int i, fd, max_fd, r;
@@ -368,8 +368,11 @@ run_command (struct command *cmd)
int outfd[2] = { -1, -1 };
char status_string[80];
get_stdout_fd = get_stdout_fd || cmd->stdout_callback != NULL;
get_stderr_fd = get_stderr_fd || cmd->capture_errors;
/* Set up a pipe to capture command output and send it to the error log. */
if (cmd->capture_errors) {
if (get_stderr_fd) {
if (pipe2 (errorfd, O_CLOEXEC) == -1) {
perrorf (cmd->g, "pipe2");
goto error;
@@ -377,7 +380,7 @@ run_command (struct command *cmd)
}
/* Set up a pipe to capture stdout for the callback. */
if (cmd->stdout_callback) {
if (get_stdout_fd) {
if (pipe2 (outfd, O_CLOEXEC) == -1) {
perrorf (cmd->g, "pipe2");
goto error;
@@ -392,14 +395,14 @@ run_command (struct command *cmd)
/* In parent, return to caller. */
if (cmd->pid > 0) {
if (cmd->capture_errors) {
if (get_stderr_fd) {
close (errorfd[1]);
errorfd[1] = -1;
cmd->errorfd = errorfd[0];
errorfd[0] = -1;
}
if (cmd->stdout_callback) {
if (get_stdout_fd) {
close (outfd[1]);
outfd[1] = -1;
cmd->outfd = outfd[0];
@@ -410,15 +413,15 @@ run_command (struct command *cmd)
}
/* Child process. */
if (cmd->capture_errors) {
if (get_stderr_fd) {
close (errorfd[0]);
if (!cmd->stdout_callback)
if (!get_stdout_fd)
dup2 (errorfd[1], 1);
dup2 (errorfd[1], 2);
close (errorfd[1]);
}
if (cmd->stdout_callback) {
if (get_stdout_fd) {
close (outfd[0]);
dup2 (outfd[1], 1);
close (outfd[1]);
@@ -615,7 +618,7 @@ guestfs___cmd_run (struct command *cmd)
if (cmd->g->verbose)
debug_command (cmd);
if (run_command (cmd) == -1)
if (run_command (cmd, false, false) == -1)
return -1;
if (loop (cmd) == -1)
@@ -624,6 +627,49 @@ guestfs___cmd_run (struct command *cmd)
return wait_command (cmd);
}
/* Fork, run the command, and returns the pid of the command,
* and its stdout and stderr file descriptors.
*
* Returns the exit status. Test it using WIF* macros.
*
* On error: Calls error(g) and returns -1.
*/
int
guestfs___cmd_run_async (struct command *cmd, pid_t *pid,
int *stdout_fd, int *stderr_fd)
{
finish_command (cmd);
if (cmd->g->verbose)
debug_command (cmd);
if (run_command (cmd, stdout_fd != NULL, stderr_fd != NULL) == -1)
return -1;
if (pid)
*pid = cmd->pid;
if (stdout_fd)
*stdout_fd = cmd->outfd;
if (stderr_fd)
*stderr_fd = cmd->errorfd;
return 0;
}
/* Wait for the command to finish.
*
* The command MUST have been started with guestfs___cmd_run_async.
*
* Returns the exit status. Test it using WIF* macros.
*
* On error: Calls error(g) and returns -1.
*/
int
guestfs___cmd_wait (struct command *cmd)
{
return wait_command (cmd);
}
void
guestfs___cmd_close (struct command *cmd)
{

3
src/guestfs-internal.h
View File

@@ -20,6 +20,7 @@
#define GUESTFS_INTERNAL_H_
#include <stdbool.h>
#include <sys/types.h>
#include <libintl.h>
@@ -870,6 +871,8 @@ extern void guestfs___cmd_set_stderr_to_stdout (struct command *);
extern void guestfs___cmd_clear_capture_errors (struct command *);
extern void guestfs___cmd_clear_close_files (struct command *);
extern int guestfs___cmd_run (struct command *);
extern int guestfs___cmd_run_async (struct command *, pid_t *pid, int *stdout_fd, int *stderr_fd);
extern int guestfs___cmd_wait (struct command *);
extern void guestfs___cmd_close (struct command *);
#ifdef HAVE_ATTRIBUTE_CLEANUP