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Implemented adivisory FreeBSD drive locking via flock(2)

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This commit is contained in:
Thomas Schmitt 2010-01-15 18:25:14 +00:00
parent 2a85fc7d91
commit 7ead54c8b9
3 changed files with 194 additions and 32 deletions
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2
cdrskin/cdrskin_timestamp.h
View File

@ -1 +1 @@
#define Cdrskin_timestamP "2010.01.14.160748"
#define Cdrskin_timestamP "2010.01.15.182615"

4
libburn/os-freebsd.h
View File

@ -57,5 +57,7 @@ typedef struct burn_drive_enumeration_state *burn_drive_enumerator_t;
To be initialized and used within sg-*.c .
*/
#define BURN_OS_TRANSPORT_DRIVE_ELEMENTS \
struct cam_device* cam;
struct cam_device* cam; \
int lock_fd; \

220
libburn/sg-freebsd.c
View File

@ -7,6 +7,7 @@
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <stdlib.h>
#include <string.h>
#include <sys/poll.h>
@ -54,6 +55,21 @@ int burn_drive_is_banned(char *device_address);
int mmc_function_spy(struct burn_drive *d, char * text);
/* ts B00113
Whether to log SCSI commands:
bit0= log in /tmp/libburn_sg_command_log
bit1= log to stderr
bit2= flush every line
*/
extern int burn_sg_log_scsi;
/* ts B00114 */
/* Storage object is in libburn/init.c
whether to strive for exclusive access to the drive
*/
extern int burn_sg_open_o_excl;
/* ts A91227 */
/** Returns the id string of the SCSI transport adapter and eventually
needed operating system facilities.
@ -351,6 +367,10 @@ int sg_close_drive(struct burn_drive * d)
cam_close_device(d->cam);
d->cam = NULL;
}
if (d->lock_fd > 0) {
close(d->lock_fd);
d->lock_fd = -1;
}
return 0;
}
@ -404,7 +424,9 @@ static void enumerate_common(char *fname, int bus_no, int host_no,
out.lun = lun_no;
out.devname = burn_strdup(fname);
out.cam = NULL;
out.lock_fd = -1;
out.start_lba= -2000000000;
out.end_lba= -2000000000;
@ -496,6 +518,8 @@ static void enumerate_common(char *fname, int bus_no, int host_no,
/* Operating system adapter is CAM */
/* Adapter specific handles and data */
out.cam = NULL;
out.lock_fd = -1;
/* Adapter specific functions */
out.grab = sg_grab;
out.release = sg_release;
@ -508,14 +532,143 @@ static void enumerate_common(char *fname, int bus_no, int host_no,
#endif /* ! Scsi_freebsd_make_own_enumeratE */
/* ts A61021: do not believe this:
we use the sg reference count to decide whether we can use the
drive or not.
if refcount is not one, drive is open somewhere else.
/* Lock the inode associated to dev_fd and the inode associated to devname.
Return OS errno, number of pass device of dev_fd, locked fd to devname,
error message.
A return value of > 0 means success, <= 0 means failure.
*/
static int freebsd_dev_lock(int dev_fd, char *devname,
int *os_errno, int *pass_dev_no, int *lock_fd, char msg[4096],
int flag)
{
int lock_denied = 0, fd_stbuf_valid, name_stbuf_valid, i, pass_l = 100;
int max_retry = 3, tries = 0;
struct stat fd_stbuf, name_stbuf;
char pass_name[16], *lock_name;
*os_errno = 0;
*pass_dev_no = -1;
*lock_fd = -1;
msg[0] = 0;
fd_stbuf_valid = !fstat(dev_fd, &fd_stbuf);
/* Try to find name of pass device by inode number */
lock_name = (char *) "effective device";
if(fd_stbuf_valid) {
for (i = 0; i < pass_l; i++) {
sprintf(pass_name, "/dev/pass%d", i);
if (stat(pass_name, &name_stbuf) != -1)
if(fd_stbuf.st_ino == name_stbuf.st_ino &&
fd_stbuf.st_dev == name_stbuf.st_dev)
break;
}
if (i < pass_l) {
lock_name = pass_name;
*pass_dev_no = i;
}
}
name_stbuf_valid = !stat(devname, &name_stbuf);
for (tries= 0; tries <= max_retry; tries++) {
lock_denied = flock(dev_fd, LOCK_EX | LOCK_NB);
*os_errno = errno;
if (lock_denied) {
if (errno == EAGAIN && tries < max_retry) {
/* <<< debugging
fprintf(stderr,
"\nlibcdio_DEBUG: EAGAIN pass, tries= %d\n",
tries);
*/
usleep(2000000);
continue;
}
sprintf(msg,
"Device busy. flock(LOCK_EX) failed on %s of %s",
strlen(lock_name) > 2000 || *pass_dev_no < 0 ?
"pass device" : lock_name,
strlen(devname) > 2000 ? "drive" : devname);
return 0;
}
break;
}
/*
fprintf(stderr, "libburn_DEBUG: flock obtained on %s of %s\n",
lock_name, devname);
*/
/* Eventually lock the official device node too */
if (fd_stbuf_valid && name_stbuf_valid &&
(fd_stbuf.st_ino != name_stbuf.st_ino ||
fd_stbuf.st_dev != name_stbuf.st_dev)) {
*lock_fd = open(devname, O_RDONLY);
if (*lock_fd == 0) {
close(*lock_fd);
*lock_fd = -1;
} if (*lock_fd > 0) {
for (tries = 0; tries <= max_retry; tries++) {
lock_denied =
flock(*lock_fd, LOCK_EX | LOCK_NB);
if (lock_denied) {
if (errno == EAGAIN &&
tries < max_retry) {
/* <<< debugging
fprintf(stderr,
"\nlibcdio_DEBUG: EAGAIN dev, tries= %d\n",
tries);
*/
usleep(2000000);
continue;
}
close(*lock_fd);
*lock_fd = -1;
sprintf(msg,
"Device busy. flock(LOCK_EX) failed on %s",
strlen(devname) > 4000 ? "drive" : devname);
return 0;
}
break;
}
}
/*
fprintf(stderr, "libburn_DEBUG: flock obtained on %s\n",
devname);
*/
}
return 1;
}
static int sg_lock(struct burn_drive *d, int flag)
{
int ret, os_errno, pass_dev_no = -1, flock_fd = -1;
char msg[4096];
ret = freebsd_dev_lock(d->cam->fd, d->devname,
&os_errno, &pass_dev_no, &flock_fd, msg, 0);
if (ret <= 0) {
libdax_msgs_submit(libdax_messenger, d->global_index,
0x00020008,
LIBDAX_MSGS_SEV_SORRY, LIBDAX_MSGS_PRIO_HIGH,
msg, os_errno, 0);
sg_close_drive(d);
return 0;
}
if (d->lock_fd > 0)
close(d->lock_fd);
d->lock_fd = flock_fd;
return 1;
}
int sg_grab(struct burn_drive *d)
{
int count, os_errno;
struct cam_device *cam;
if (mmc_function_spy(d, "sg_grab") <= 0)
@ -528,23 +681,19 @@ int sg_grab(struct burn_drive *d)
cam = cam_open_device(d->devname, O_RDWR);
if (cam == NULL) {
os_errno = errno;
libdax_msgs_submit(libdax_messenger, d->global_index,
0x00020003,
LIBDAX_MSGS_SEV_SORRY, LIBDAX_MSGS_PRIO_HIGH,
"Could not grab drive", os_errno, 0);
"Could not grab drive", errno, 0);
return 0;
}
count = 1;
if (1 == count) {
d->cam = cam;
fcntl(cam->fd, F_SETOWN, getpid());
d->released = 0;
return 1;
}
burn_print(1, "could not acquire drive - already open\n");
sg_close_drive(d);
return 0;
d->cam = cam;
if (burn_sg_open_o_excl & 63)
if (sg_lock(d, 0) <= 0)
return 0;
fcntl(cam->fd, F_SETOWN, getpid());
d->released = 0;
return 1;
}
@ -572,10 +721,11 @@ int sg_release(struct burn_drive *d)
int sg_issue_command(struct burn_drive *d, struct command *c)
{
int done = 0, err, sense_len;
int done = 0, err, sense_len, ret;
union ccb *ccb;
char buf[161];
static FILE *fp = NULL;
snprintf(buf, sizeof (buf), "sg_issue_command d->cam=%p d->released=%d",
(void*)d->cam, d->released);
mmc_function_spy(NULL, buf);
@ -584,6 +734,15 @@ int sg_issue_command(struct burn_drive *d, struct command *c)
c->error = 0;
return 0;
}
if (burn_sg_log_scsi & 1) {
if (fp == NULL) {
fp= fopen("/tmp/libburn_sg_command_log", "a");
fprintf(fp,
"\n-----------------------------------------\n");
}
}
if (burn_sg_log_scsi & 3)
scsi_log_cmd(c,fp,0);
c->error = 0;
@ -632,12 +791,6 @@ int sg_issue_command(struct burn_drive *d, struct command *c)
/* touch page so we can use valgrind */
memset(c->page->data, 0, BUFFER_SIZE);
} else {
/* ts A90430 */
/* a ssert(c->page->bytes > 0); */
if (c->page->bytes <= 0) {
c->error = 1;
return 0;
}
ccb->csio.dxfer_len = c->page->bytes;
}
} else {
@ -653,12 +806,11 @@ int sg_issue_command(struct burn_drive *d, struct command *c)
LIBDAX_MSGS_SEV_FATAL, LIBDAX_MSGS_PRIO_HIGH,
"Failed to transfer command to drive",
errno, 0);
cam_freeccb(ccb);
sg_close_drive(d);
d->released = 1;
d->busy = BURN_DRIVE_IDLE;
c->error = 1;
return -1;
{ret = -1; goto ex;}
}
/* XXX */
@ -671,8 +823,7 @@ int sg_issue_command(struct burn_drive *d, struct command *c)
if ((ccb->ccb_h.status & CAM_STATUS_MASK) != CAM_REQ_CMP) {
if (!c->retry) {
c->error = 1;
cam_freeccb(ccb);
return 1;
{ret = 1; goto ex;}
}
switch (scsi_error(d, c->sense, 0)) {
case RETRY:
@ -687,8 +838,17 @@ int sg_issue_command(struct burn_drive *d, struct command *c)
done = 1;
}
} while (!done);
ret = 1;
ex:;
if (c->error)
scsi_notify_error(d, c, c->sense, 18, 0);
if (burn_sg_log_scsi & 3)
/* >>> Need own duration time measurement. Then remove bit1 */
scsi_log_err(c, fp, c->sense, 0, (c->error != 0) | 2);
cam_freeccb(ccb);
return 1;
return ret;
}