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Only allow one return from poll_daemon(). If a child polldaemon was

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successfully created it must _exit() once it completes.

Update _become_daemon() to differentiate between a failed fork() and a
successful fork().

Added lvm_return_code() to lvmcmdline.[ch]
This commit is contained in:
Mike Snitzer 2010-01-11 19:19:17 +00:00
parent ccd6d287eb
commit 94d4a90f27
3 changed files with 41 additions and 9 deletions
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1
tools/lvm2cmdline.h
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@ -35,6 +35,7 @@ struct cmd_context *init_lvm(void);
void lvm_register_commands(void);
int lvm_split(char *str, int *argc, char **argv, int max);
int lvm_run_command(struct cmd_context *cmd, int argc, char **argv);
int lvm_return_code(int ret);
int lvm_shell(struct cmd_context *cmd, struct cmdline_context *cmdline);
#endif

9
tools/lvmcmdline.c
View File

@ -1070,6 +1070,11 @@ int lvm_run_command(struct cmd_context *cmd, int argc, char **argv)
return ret;
}
int lvm_return_code(int ret)
{
return (ret == ECMD_PROCESSED ? 0 : ret);
}
int lvm_split(char *str, int *argc, char **argv, int max)
{
char *b = str, *e;
@ -1389,7 +1394,5 @@ int lvm2_main(int argc, char **argv)
out:
lvm_fin(cmd);
if (ret == ECMD_PROCESSED)
ret = 0;
return ret;
return lvm_return_code(ret);
}

40
tools/polldaemon.c
View File

@ -15,6 +15,7 @@
#include "tools.h"
#include "polldaemon.h"
#include "lvm2cmdline.h"
#include <signal.h>
#include <sys/wait.h>
@ -23,6 +24,12 @@ static void _sigchld_handler(int sig __attribute((unused)))
while (wait4(-1, NULL, WNOHANG | WUNTRACED, NULL) > 0) ;
}
/*
* returns:
* -1 if the fork failed
* 0 if the parent
* 1 if the child
*/
static int _become_daemon(struct cmd_context *cmd)
{
pid_t pid;
@ -37,7 +44,7 @@ static int _become_daemon(struct cmd_context *cmd)
if ((pid = fork()) == -1) {
log_error("fork failed: %s", strerror(errno));
return 1;
return -1;
}
/* Parent */
@ -232,12 +239,20 @@ static void _poll_for_all_vgs(struct cmd_context *cmd,
}
}
/*
* Only allow *one* return from poll_daemon() (the parent).
* If there is a child it must exit (ignoring the memory leak messages).
* - 'background' is advisory so a child polldaemon may not be used even
* if it was requested.
*/
int poll_daemon(struct cmd_context *cmd, const char *name, const char *uuid,
unsigned background,
uint32_t lv_type, struct poll_functions *poll_fns,
const char *progress_title)
{
struct daemon_parms parms;
int daemon_mode = 0;
int ret = ECMD_PROCESSED;
parms.aborting = arg_is_set(cmd, abort_ARG);
parms.background = background;
@ -260,9 +275,11 @@ int poll_daemon(struct cmd_context *cmd, const char *name, const char *uuid,
}
if (parms.background) {
if (!_become_daemon(cmd))
return ECMD_PROCESSED; /* Parent */
parms.progress_display = 0;
daemon_mode = _become_daemon(cmd);
if (daemon_mode == 0)
return ECMD_PROCESSED; /* Parent */
else if (daemon_mode == 1)
parms.progress_display = 0; /* Child */
/* FIXME Use wait_event (i.e. interval = 0) and */
/* fork one daemon per copy? */
}
@ -273,10 +290,21 @@ int poll_daemon(struct cmd_context *cmd, const char *name, const char *uuid,
if (name) {
if (!_wait_for_single_lv(cmd, name, uuid, &parms)) {
stack;
return ECMD_FAILED;
ret = ECMD_FAILED;
}
} else
_poll_for_all_vgs(cmd, &parms);
return ECMD_PROCESSED;
if (parms.background && daemon_mode == 1) {
/*
* child was successfully forked:
* background polldaemon must not return to the caller
* because it will redundantly continue performing the
* caller's task (that the parent already performed)
*/
/* FIXME Attempt proper cleanup */
_exit(lvm_return_code(ret));
}
return ret;
}