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libmount: add support for mount -a --fork 

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2011-12-02 18:20:34 +01:00
parent ede8a60e05
commit d2c97887fe
6 changed files with 218 additions and 29 deletions
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53
libmount/samples/mount.c
View File

@ -136,10 +136,8 @@ static void print_all(struct libmnt_context *cxt, char *pattern, int show_label)
/*
* mount -a [-F]
* ... -F is not supported yet (TODO)
*/
static int mount_all(struct libmnt_context *cxt,
int forkme __attribute__((unused)))
static int mount_all(struct libmnt_context *cxt)
{
struct libmnt_iter *itr;
struct libmnt_fs *fs;
@ -160,24 +158,39 @@ static int mount_all(struct libmnt_context *cxt,
printf(ignored == 1 ? _("%-25s: ignored\n") :
_("%-25s: already mounted\n"),
tgt);
} else if (!mnt_context_get_status(cxt)) {
if (mntrc > 0) {
errno = mntrc;
printf(_("%-25s: failed: %s\n"), tgt,
strerror(mntrc));
rc |= EX_FAIL;
} else {
printf(_("%-25s: failed\n"), tgt);
rc |= EX_SYSERR;
}
} else {
if (mnt_context_is_verbose(cxt))
printf("%-25s: successfully mounted\n", tgt);
rc |= EX_SOMEOK;
} else if (mnt_context_is_fork(cxt)) {
printf("%-25s: mount successfully forked\n", tgt);
} else {
if (!mnt_context_get_status(cxt)) {
if (mntrc > 0) {
errno = mntrc;
printf(_("%-25s: failed: %s\n"), tgt,
strerror(mntrc));
rc |= EX_FAIL;
} else {
printf(_("%-25s: failed\n"), tgt);
rc |= EX_SYSERR;
}
} else {
if (mnt_context_is_verbose(cxt))
printf("%-25s: successfully mounted\n", tgt);
rc |= EX_SOMEOK;
}
}
}
if (mnt_context_is_parent(cxt)) {
/* wait for mount --fork children */
int nerrs = 0, nchildren = 0;
rc = mnt_context_wait_for_children(cxt, &nchildren, &nerrs);
if (!rc && nchildren)
rc = nchildren == nerrs ? EX_FAIL : EX_SOMEOK;
}
return rc;
}
@ -251,7 +264,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
int main(int argc, char **argv)
{
int c, rc = EX_SUCCESS, all = 0, forkme = 0, show_labels = 0;
int c, rc = EX_SUCCESS, all = 0, show_labels = 0;
struct libmnt_context *cxt;
char *source = NULL, *srcbuf = NULL;
char *types = NULL;
@ -332,7 +345,7 @@ int main(int argc, char **argv)
mnt_context_enable_fake(cxt, TRUE);
break;
case 'F':
forkme = 1;
mnt_context_enable_fork(cxt, TRUE);
break;
case 'h':
usage(stdout);
@ -445,7 +458,7 @@ int main(int argc, char **argv)
/*
* A) Mount all
*/
rc = mount_all(cxt, forkme);
rc = mount_all(cxt);
goto done;
} else if (argc == 0 && source) {

137
libmount/src/context.c
View File

@ -33,6 +33,8 @@
#include "mountP.h"
#include <sys/wait.h>
/**
* mnt_new_context:
*
@ -94,6 +96,8 @@ void mnt_free_context(struct libmnt_context *cxt)
mnt_free_lock(cxt->lock);
mnt_free_update(cxt->update);
free(cxt->children);
DBG(CXT, mnt_debug_h(cxt, "<---- free"));
free(cxt);
}
@ -161,6 +165,7 @@ int mnt_reset_context(struct libmnt_context *cxt)
cxt->flags |= (fl & MNT_FL_NOHELPERS);
cxt->flags |= (fl & MNT_FL_LOOPDEL);
cxt->flags |= (fl & MNT_FL_LAZY);
cxt->flags |= (fl & MNT_FL_FORK);
cxt->flags |= (fl & MNT_FL_FORCE);
cxt->flags |= (fl & MNT_FL_NOCANONICALIZE);
cxt->flags |= (fl & MNT_FL_RDONLY_UMOUNT);
@ -171,10 +176,13 @@ static int set_flag(struct libmnt_context *cxt, int flag, int enable)
{
if (!cxt)
return -EINVAL;
if (enable)
if (enable) {
DBG(CXT, mnt_debug_h(cxt, "enabling flag %04x", flag));
cxt->flags |= flag;
else
} else {
DBG(CXT, mnt_debug_h(cxt, "disabling flag %04x", flag));
cxt->flags &= ~flag;
}
return 0;
}
@ -253,6 +261,21 @@ int mnt_context_enable_lazy(struct libmnt_context *cxt, int enable)
return set_flag(cxt, MNT_FL_LAZY, enable);
}
/**
* mnt_context_enable_fork:
* @cxt: mount context
* @enable: TRUE or FALSE
*
* Enable/disable fork(2) call in mnt_context_next_mount() (see mount(8) man
* page, option -F).
*
* Returns: 0 on success, negative number in case of error.
*/
int mnt_context_enable_fork(struct libmnt_context *cxt, int enable)
{
return set_flag(cxt, MNT_FL_FORK, enable);
}
/**
* mnt_context_is_lazy:
* @cxt: mount context
@ -1683,6 +1706,116 @@ int mnt_context_is_fs_mounted(struct libmnt_context *cxt,
return 0;
}
static int mnt_context_add_child(struct libmnt_context *cxt, pid_t pid)
{
pid_t *pids;
if (!cxt)
return -EINVAL;
pids = realloc(cxt->children, sizeof(pid_t) * cxt->nchildren + 1);
if (!pids)
return -ENOMEM;
DBG(CXT, mnt_debug_h(cxt, "add new child %d", pid));
cxt->children = pids;
cxt->children[cxt->nchildren++] = pid;
return 0;
}
int mnt_fork_context(struct libmnt_context *cxt)
{
int rc = 0;
pid_t pid;
if (!mnt_context_is_parent(cxt))
return -EINVAL;
DBG(CXT, mnt_debug_h(cxt, "forking context"));
DBG_FLUSH;
pid = fork();
switch (pid) {
case -1: /* error */
DBG(CXT, mnt_debug_h(cxt, "fork failed %m"));
return -errno;
case 0: /* child */
cxt->pid = getpid();
cxt->flags &= ~MNT_FL_FORK;
DBG(CXT, mnt_debug_h(cxt, "child created"));
break;
default:
rc = mnt_context_add_child(cxt, pid);
break;
}
return rc;
}
int mnt_context_wait_for_children(struct libmnt_context *cxt,
int *nchildren, int *nerrs)
{
int i;
if (!cxt)
return -EINVAL;
assert(mnt_context_is_parent(cxt));
for (i = 0; i < cxt->nchildren; i++) {
pid_t pid = cxt->children[i];
int rc = 0, ret = 0;
if (!pid)
continue;
do {
DBG(CXT, mnt_debug_h(cxt,
"waiting for child (%d/%d): %d",
i + 1, cxt->nchildren, pid));
errno = 0;
rc = waitpid(pid, &ret, 0);
} while (rc == -1 && errno == EINTR);
if (nchildren)
(*nchildren)++;
if (rc != -1 && nerrs) {
if (WIFEXITED(ret))
(*nerrs) += WEXITSTATUS(ret) == 0 ? 0 : 1;
else
(*nerrs)++;
}
cxt->children[i] = 0;
}
cxt->nchildren = 0;
free(cxt->children);
cxt->children = NULL;
return 0;
}
int mnt_context_is_fork(struct libmnt_context *cxt)
{
return cxt && (cxt->flags & MNT_FL_FORK);
}
int mnt_context_is_parent(struct libmnt_context *cxt)
{
return mnt_context_is_fork(cxt) && cxt->pid == 0;
}
int mnt_context_is_child(struct libmnt_context *cxt)
{
return !mnt_context_is_fork(cxt) && cxt->pid;
}
#ifdef TEST_PROGRAM
struct libmnt_lock *lock;

28
libmount/src/context_mount.c
View File

@ -762,12 +762,30 @@ int mnt_context_next_mount(struct libmnt_context *cxt,
return 0;
}
if (mnt_context_is_fork(cxt)) {
rc = mnt_fork_context(cxt);
if (rc)
return rc; /* fork error */
if (mnt_context_is_parent(cxt)) {
return 0; /* parent */
}
}
/* child or non-forked */
rc = mnt_context_set_fs(cxt, *fs);
if (rc)
return rc;
rc = mnt_context_mount(cxt);
if (mntrc)
*mntrc = rc;
if (!rc) {
rc = mnt_context_mount(cxt);
if (mntrc)
*mntrc = rc;
}
if (mnt_context_is_child(cxt)) {
DBG(CXT, mnt_debug_h(cxt, "next-mount: child exit [rc=%d]", rc));
DBG_FLUSH;
exit(rc);
}
return 0;
}

8
libmount/src/libmount.h.in
View File

@ -390,6 +390,7 @@ extern int mnt_context_disable_mtab(struct libmnt_context *cxt, int disable);
extern int mnt_context_enable_force(struct libmnt_context *cxt, int enable);
extern int mnt_context_enable_verbose(struct libmnt_context *cxt, int enable);
extern int mnt_context_enable_loopdel(struct libmnt_context *cxt, int enable);
extern int mnt_context_enable_fork(struct libmnt_context *cxt, int enable);
extern int mnt_context_get_optsmode(struct libmnt_context *cxt);
extern int mnt_context_is_lazy(struct libmnt_context *cxt);
@ -400,6 +401,13 @@ extern int mnt_context_is_nomtab(struct libmnt_context *cxt);
extern int mnt_context_is_force(struct libmnt_context *cxt);
extern int mnt_context_is_verbose(struct libmnt_context *cxt);
extern int mnt_context_is_fork(struct libmnt_context *cxt);
extern int mnt_context_is_parent(struct libmnt_context *cxt);
extern int mnt_context_is_child(struct libmnt_context *cxt);
extern int mnt_context_wait_for_children(struct libmnt_context *cxt,
int *nchildren, int *nerrs);
extern int mnt_context_is_fs_mounted(struct libmnt_context *cxt,
struct libmnt_fs *fs, int *mounted);

5
libmount/src/libmount.sym
View File

@ -208,5 +208,10 @@ global:
MOUNT_2.21 {
global:
mnt_context_enable_fork;
mnt_context_is_child;
mnt_context_is_fork;
mnt_context_is_parent;
mnt_context_next_umount;
mnt_context_wait_for_children;
} MOUNT_2.20;

16
libmount/src/mountP.h
View File

@ -61,12 +61,16 @@
# define DBG(m, x) do { \
if ((MNT_DEBUG_ ## m) & libmount_debug_mask) { \
fprintf(stderr, "libmount: %8s: ", # m); \
fprintf(stderr, "%d: libmount: %8s: ", getpid(), # m); \
x; \
} \
} while (0)
# define DBG_FLUSH do { fflush(stderr); } while(0)
# define DBG_FLUSH do { \
if (libmount_debug_mask && \
libmount_debug_mask != MNT_DEBUG_INIT) \
fflush(stderr); \
} while(0)
extern int libmount_debug_mask;
@ -299,6 +303,11 @@ struct libmnt_context
char *orig_user; /* original (non-fixed) user= option */
pid_t *children; /* "mount -a --fork" PIDs */
int nchildren; /* number of children */
pid_t pid; /* 0=parent; PID=child */
int syscall_status; /* 1: not called yet, 0: success, <0: -errno */
};
@ -313,6 +322,7 @@ struct libmnt_context
#define MNT_FL_FORCE (1 << 8)
#define MNT_FL_NOCANONICALIZE (1 << 9)
#define MNT_FL_RDONLY_UMOUNT (1 << 11) /* remount,ro after EBUSY umount(2) */
#define MNT_FL_FORK (1 << 12)
#define MNT_FL_EXTERN_FS (1 << 15) /* cxt->fs is not private */
#define MNT_FL_EXTERN_FSTAB (1 << 16) /* cxt->fstab is not private */
@ -370,6 +380,8 @@ extern int mnt_context_setup_loopdev(struct libmnt_context *cxt);
extern int mnt_context_delete_loopdev(struct libmnt_context *cxt);
extern int mnt_context_clear_loopdev(struct libmnt_context *cxt);
extern int mnt_fork_context(struct libmnt_context *cxt);
/* tab_update.c */
extern struct libmnt_fs *mnt_update_get_fs(struct libmnt_update *upd);
extern int mnt_update_set_filename(struct libmnt_update *upd,