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zgetdump: Avoid using PATH_MAX

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Using inappropriate sizes for snprintf() leads to the following compile
warnings:

dfi_s390mv.c: In function ‘dev_from_busid’:
dfi_s390mv.c:116:34: warning: ‘/online’ directive output may be
truncated writing 7 bytes into a region of size between 1 and 4096
[-Wformat-truncation=]
  snprintf(tmp_file, PATH_MAX, "%s/online", dev_file);
                                  ^~~~~~~
dfi_s390mv.c:116:2: note: ‘snprintf’ output between 8 and 4103 bytes
into a destination of size 4096
  snprintf(tmp_file, PATH_MAX, "%s/online", dev_file);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
dfi_s390mv.c:143:35: warning: ‘%s’ directive output may be truncated
writing up to 255 bytes into a region of size between 0 and 4095
[-Wformat-truncation=]
  snprintf(tmp_file, PATH_MAX, "%s/%s/dev", dev_file, direntp->d_name);
                                   ^~
dfi_s390mv.c:143:2: note: ‘snprintf’ output between 6 and 4356 bytes
into a destination of size 4096
  snprintf(tmp_file, PATH_MAX, "%s/%s/dev", dev_file, direntp->d_name);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A simple fix would be to use different suitable fixed sizes for tmp_file
and dev_file. However, the code can be improved here a little.

Use the libutil function util_path_sysfs() to build the sysfs path
string. This is more robust, as the function will figure out the correct
mount point of the sysfs. util_path_sysfs() will also terminate
execution, if no sysfs mount point could be found. That means, we can
get rid of check_sysfs().
Furthermore, the two variables (tmp_file, dev_file) can be combined to
one. Also, check the return value of open() and act accordingly.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
This commit is contained in:
Jan Höppner
2018-11-05 12:57:28 +01:00
parent b5a7b13e71
commit 70a79fab3c
2 changed files with 50 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
zdump/dfi_s390mv.c
View File

@@ -10,6 +10,7 @@
*/
#include <dirent.h>
#include <err.h>
#include <fcntl.h>
#include <linux/fs.h>
#include <stdio.h>
@@ -20,6 +21,8 @@
#include <time.h>
#include <unistd.h>
#include "lib/util_path.h"
#include "zgetdump.h"
#include "dfi_s390mv.h"
@@ -102,19 +105,25 @@ static void em_init(struct vol *vol)
*/
static enum dev_status dev_from_busid(char *bus_id, dev_t *dev)
{
char tmp_file[PATH_MAX], dev_file[PATH_MAX];
struct dirent *direntp;
int fh, minor, major;
char buf[10];
DIR *fh_dir;
char *sysfs;
snprintf(dev_file, PATH_MAX, "%s/%s", SYSFS_BUSDIR, bus_id);
fh_dir = opendir(dev_file);
sysfs = util_path_sysfs("%s/%s", SYSFS_BUSDIR, bus_id);
fh_dir = opendir(sysfs);
free(sysfs);
if (!fh_dir)
return DEV_UNDEFINED;
snprintf(tmp_file, PATH_MAX, "%s/online", dev_file);
fh = open(tmp_file, O_RDONLY);
sysfs = util_path_sysfs("%s/%s/online", SYSFS_BUSDIR, bus_id);
fh = open(sysfs, O_RDONLY);
if (fh == -1) {
warnx("Could not open \"%s\" (%s)", sysfs, strerror(errno));
goto err;
}
free(sysfs);
if (read(fh, buf, 1) == -1)
ERR_EXIT_ERRNO("Could not read online attribute");
close(fh);
@@ -128,27 +137,49 @@ static enum dev_status dev_from_busid(char *bus_id, dev_t *dev)
closedir(fh_dir);
if (direntp == NULL) {
snprintf(dev_file, PATH_MAX, "%s/%s/block", SYSFS_BUSDIR,
bus_id);
fh_dir = opendir(dev_file);
if (!fh_dir)
ERR_EXIT_ERRNO("Could not open \"%s\"", dev_file);
sysfs = util_path_sysfs("%s/%s/block", SYSFS_BUSDIR, bus_id);
fh_dir = opendir(sysfs);
if (!fh_dir) {
warnx("Could not open \"%s\" (%s) ",
sysfs, strerror(errno));
goto err;
}
while ((direntp = readdir(fh_dir)))
if (strncmp(direntp->d_name, "dasd", 4) == 0)
break;
closedir(fh_dir);
if (direntp == NULL)
ERR_EXIT("Problem with contents of \"%s\"", dev_file);
if (direntp == NULL) {
warnx("Problem with contents of \"%s\"", sysfs);
goto err;
}
free(sysfs);
}
sysfs = util_path_sysfs("%s/%s/%s/dev",
SYSFS_BUSDIR, bus_id, direntp->d_name);
fh = open(sysfs, O_RDONLY);
if (fh == -1) {
warnx("Could not open \"%s\" (%s)", sysfs, strerror(errno));
goto err;
}
if (read(fh, buf, sizeof(buf)) == -1) {
warnx("Could not read dev file (%s)", strerror(errno));
goto err;
}
snprintf(tmp_file, PATH_MAX, "%s/%s/dev", dev_file, direntp->d_name);
fh = open(tmp_file, O_RDONLY);
if (read(fh, buf, sizeof(buf)) == -1)
ERR_EXIT_ERRNO("Could not read dev file");
close(fh);
if (sscanf(buf, "%i:%i", &major, &minor) != 2)
ERR_EXIT("Malformed content of \"%s\": %s", tmp_file, buf);
if (sscanf(buf, "%i:%i", &major, &minor) != 2) {
warnx("Malformed content of \"%s\": %s", sysfs, buf);
goto err;
}
*dev = makedev(major, minor);
free(sysfs);
return DEV_ONLINE;
err:
free(sysfs);
exit(EXIT_FAILURE);
}
/*
@@ -467,19 +498,6 @@ fail:
return rc;
}
/*
* Check if sysfs is available
*/
static void check_sysfs(void)
{
DIR *fh_dir;
fh_dir = opendir(SYSFS_BUSDIR);
if (!fh_dir)
ERR_EXIT_ERRNO("Could not open %s\n", SYSFS_BUSDIR);
closedir(fh_dir);
}
/*
* Read dump tool from DASD and check if we have a multi-volume dump tool
*/
@@ -503,8 +521,6 @@ static void volumes_init(void)
u64 mem_off = 0;
unsigned int i;
check_sysfs();
for (i = 0; i < l.table.vol_cnt; i++) {
l.vol_vec[i].nr = i;
vol_init(&l.vol_vec[i], &l.table.vol_parm[i], l.table.ssid[i],

2
zdump/dfi_s390mv.h
View File

@@ -13,7 +13,7 @@
#include "lib/zt_common.h"
#define SYSFS_BUSDIR "/sys/bus/ccw/devices"
#define SYSFS_BUSDIR "bus/ccw/devices"
#define MAX_VOLUMES 32
/*