* [LTP] [PATCH] Fix search for device ID in tst_find_backing_dev()
@ 2020-09-25 10:27 Martin Doucha
2020-09-25 10:31 ` Martin Doucha
2020-09-25 13:01 ` Cyril Hrubis
0 siblings, 2 replies; 3+ messages in thread
From: Martin Doucha @ 2020-09-25 10:27 UTC (permalink / raw)
To: ltp
The current search using substrings can lead to false positives, e.g. search
for device 0:5 could return device 10:50 instead. Parse device IDs in
/proc/self/mountinfo properly using sscanf() and also check whether the device
was really found.
Signed-off-by: Martin Doucha <mdoucha@suse.cz>
---
lib/tst_device.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/lib/tst_device.c b/lib/tst_device.c
index 0e98a7280..c096b418b 100644
--- a/lib/tst_device.c
+++ b/lib/tst_device.c
@@ -497,21 +497,26 @@ unsigned long tst_dev_bytes_written(const char *dev)
void tst_find_backing_dev(const char *path, char *dev)
{
- char fmt[20];
struct stat buf;
FILE *file;
char line[PATH_MAX];
char *pre = NULL;
char *next = NULL;
+ unsigned int dev_major, dev_minor, line_mjr, line_mnr;
if (stat(path, &buf) < 0)
tst_brkm(TWARN | TERRNO, NULL, "stat() failed");
- snprintf(fmt, sizeof(fmt), "%u:%u", major(buf.st_dev), minor(buf.st_dev));
+ dev_major = major(buf.st_dev);
+ dev_minor = minor(buf.st_dev);
file = SAFE_FOPEN(NULL, "/proc/self/mountinfo", "r");
+ *dev = '\0';
while (fgets(line, sizeof(line), file)) {
- if (strstr(line, fmt) != NULL) {
+ if (sscanf(line, "%*d %*d %d:%d", &line_mjr, &line_mnr) != 2)
+ continue;
+
+ if (line_mjr == dev_major && line_mnr == dev_minor) {
pre = strstr(line, " - ");
pre = strtok_r(pre, " ", &next);
pre = strtok_r(NULL, " ", &next);
@@ -523,8 +528,11 @@ void tst_find_backing_dev(const char *path, char *dev)
SAFE_FCLOSE(NULL, file);
+ if (!*dev)
+ tst_brkm(TBROK, NULL, "Cannot find block device for %s", path);
+
if (stat(dev, &buf) < 0)
- tst_brkm(TWARN | TERRNO, NULL, "stat(%s) failed", dev);
+ tst_brkm(TWARN | TERRNO, NULL, "stat(%s) failed", dev);
if (S_ISBLK(buf.st_mode) != 1)
tst_brkm(TCONF, NULL, "dev(%s) isn't a block dev", dev);
--
2.28.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [LTP] [PATCH] Fix search for device ID in tst_find_backing_dev()
2020-09-25 10:27 [LTP] [PATCH] Fix search for device ID in tst_find_backing_dev() Martin Doucha
@ 2020-09-25 10:31 ` Martin Doucha
2020-09-25 13:01 ` Cyril Hrubis
1 sibling, 0 replies; 3+ messages in thread
From: Martin Doucha @ 2020-09-25 10:31 UTC (permalink / raw)
To: ltp
On 25. 09. 20 12:27, Martin Doucha wrote:
> The current search using substrings can lead to false positives, e.g. search
> for device 0:5 could return device 10:50 instead. Parse device IDs in
> /proc/self/mountinfo properly using sscanf() and also check whether the device
> was really found.
>
> Signed-off-by: Martin Doucha <mdoucha@suse.cz>
I forgot to add an extra comment that I still don't like that the search
uses fixed-size buffer without properly handling lines that are too long
but let's keep the fix simple for now. We can fix long line handling
after the release.
--
Martin Doucha mdoucha@suse.cz
QA Engineer for Software Maintenance
SUSE LINUX, s.r.o.
CORSO IIa
Krizikova 148/34
186 00 Prague 8
Czech Republic
^ permalink raw reply [flat|nested] 3+ messages in thread
* [LTP] [PATCH] Fix search for device ID in tst_find_backing_dev()
2020-09-25 10:27 [LTP] [PATCH] Fix search for device ID in tst_find_backing_dev() Martin Doucha
2020-09-25 10:31 ` Martin Doucha
@ 2020-09-25 13:01 ` Cyril Hrubis
1 sibling, 0 replies; 3+ messages in thread
From: Cyril Hrubis @ 2020-09-25 13:01 UTC (permalink / raw)
To: ltp
Hi!
Applied, thanks.
--
Cyril Hrubis
chrubis@suse.cz
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-09-25 10:27 [LTP] [PATCH] Fix search for device ID in tst_find_backing_dev() Martin Doucha
2020-09-25 10:31 ` Martin Doucha
2020-09-25 13:01 ` Cyril Hrubis
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