AW: [PATCH v2 4/9] loop:refactor: extract subfunction set_loop_info()
Walter Harms
wharms at bfs.de
Fri Nov 18 12:27:30 UTC 2022
on other minor
if (rc && errno == ENXIO)
turn it on its head safes one indent level
if ( !rc || errno != ENXIO )
return -1; // failed to get loopinfo
jm2c
________________________________________
Von: busybox <busybox-bounces at busybox.net> im Auftrag von Xiaoming Ni <nixiaoming at huawei.com>
Gesendet: Freitag, 18. November 2022 13:14:43
An: busybox at busybox.net; vda.linux at googlemail.com; cand at gmx.com; explorer09 at gmail.com
Cc: wangle6 at huawei.com
Betreff: [PATCH v2 4/9] loop:refactor: extract subfunction set_loop_info()
Step 4 of micro-refactoring the set_loop():
Extract subfunction set_loop_info() from set_loop()
function old new delta
set_loop 734 700 -34
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-34) Total: -34 bytes
Signed-off-by: Xiaoming Ni <nixiaoming at huawei.com>
---
libbb/loop.c | 91 +++++++++++++++++++++++++++-------------------------
1 file changed, 47 insertions(+), 44 deletions(-)
diff --git a/libbb/loop.c b/libbb/loop.c
index 91c3a45c4..89adc4f94 100644
--- a/libbb/loop.c
+++ b/libbb/loop.c
@@ -126,6 +126,47 @@ static int open_file(const char *file, unsigned flags, int *mode)
return ffd;
}
+static int set_loop_info(int ffd, int lfd, const char *file,
+ unsigned long long offset, unsigned long long sizelimit, unsigned flags)
+{
+ int rc;
+ bb_loop_info loopinfo;
+
+ rc = ioctl(lfd, BB_LOOP_GET_STATUS, &loopinfo);
+
+ /* If device is free, try to claim it */
+ if (rc && errno == ENXIO) {
+ /* Associate free loop device with file */
+ if (ioctl(lfd, LOOP_SET_FD, ffd)) {
+ return -1;
+ }
+ memset(&loopinfo, 0, sizeof(loopinfo));
+ safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
+ loopinfo.lo_offset = offset;
+ loopinfo.lo_sizelimit = sizelimit;
+ /*
+ * Used by mount to set LO_FLAGS_AUTOCLEAR.
+ * LO_FLAGS_READ_ONLY is not set because RO is controlled by open type of the file.
+ * Note that closing LO_FLAGS_AUTOCLEARed lfd before mount
+ * is wrong (would free the loop device!)
+ */
+ loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY);
+ rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
+ if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) {
+ /* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */
+ /* (this code path is not tested) */
+ loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR;
+ rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
+ }
+ if (rc == 0) {
+ return lfd;
+ }
+ /* failure, undo LOOP_SET_FD */
+ ioctl(lfd, LOOP_CLR_FD, 0); // actually, 0 param is unnecessary
+ }
+ return -1;
+}
+
/* Returns opened fd to the loop device, <0 on error.
* *device is loop device to use, or if *device==NULL finds a loop device to
* mount it on and sets *device to a strdup of that loop device name.
@@ -135,7 +176,6 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
{
char dev[LOOP_NAMESIZE];
char *try;
- bb_loop_info loopinfo;
struct stat statbuf;
int i, lfd, ffd, mode, rc;
@@ -190,49 +230,12 @@ int FAST_FUNC set_loop(char **device, const char *file, unsigned long long offse
}
goto try_next_loopN;
}
-
- rc = ioctl(lfd, BB_LOOP_GET_STATUS, &loopinfo);
-
- /* If device is free, try to claim it */
- if (rc && errno == ENXIO) {
- /* Associate free loop device with file */
- if (ioctl(lfd, LOOP_SET_FD, ffd)) {
- close(lfd);
- /* Ouch. Are we racing with other mount? */
- if (!*device) {
-//TODO: add "if (--failcount != 0) ..."?
- continue;
- } else {
- break;
- }
- }
- memset(&loopinfo, 0, sizeof(loopinfo));
- safe_strncpy((char *)loopinfo.lo_file_name, file, LO_NAME_SIZE);
- loopinfo.lo_offset = offset;
- loopinfo.lo_sizelimit = sizelimit;
- /*
- * Used by mount to set LO_FLAGS_AUTOCLEAR.
- * LO_FLAGS_READ_ONLY is not set because RO is controlled by open type of the file.
- * Note that closing LO_FLAGS_AUTOCLEARed lfd before mount
- * is wrong (would free the loop device!)
- */
- loopinfo.lo_flags = (flags & ~BB_LO_FLAGS_READ_ONLY);
- rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
- if (rc != 0 && (loopinfo.lo_flags & BB_LO_FLAGS_AUTOCLEAR)) {
- /* Old kernel, does not support LO_FLAGS_AUTOCLEAR? */
- /* (this code path is not tested) */
- loopinfo.lo_flags -= BB_LO_FLAGS_AUTOCLEAR;
- rc = ioctl(lfd, BB_LOOP_SET_STATUS, &loopinfo);
- }
- if (rc == 0) {
- /* SUCCESS! */
- if (!*device) /* was looping in search of free "/dev/loopN"? */
- *device = xstrdup(dev);
- rc = lfd; /* return this */
- break;
- }
- /* failure, undo LOOP_SET_FD */
- ioctl(lfd, LOOP_CLR_FD, 0); // actually, 0 param is unnecessary
+ rc = set_loop_info(ffd, lfd, file, offset, sizelimit, flags);
+ if (rc == lfd) {
+ /* SUCCESS! */
+ if (!*device)
+ *device = xstrdup(dev);
+ break;
}
close(lfd);
try_next_loopN:
--
2.27.0
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