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dasdinfo: Fix GCC 7 overflow warning

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With GCC 7 we get the following warning as a potential overflow might
happen, if d_name gets too big:

dasdinfo.c: In function 'main':
dasdinfo.c:611:37: warning: '%s' directive writing up to 255 bytes into
  a region of size 69 [-Wformat-overflow=]
   sprintf(sys_dev_path, "/sys/block/%s/dev", dir_entry->d_name);
                                     ^~
dasdinfo.c:611:3: note: 'sprintf' output between 16 and 271 bytes into a
  destination of size 80
   sprintf(sys_dev_path, "/sys/block/%s/dev", dir_entry->d_name);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This could be fixed by simply increasing the buffer size. However, there
is a little bit more to it and the way files are currently read can be
simplified.
Do this by using the libutil functions to read files and clean up a
little along the way.

Reviewed-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
This commit is contained in:
Jan Höppner
2017-09-07 16:55:51 +02:00
committed by Michael Holzheu
parent cd085dc721
commit 61b60baf57
1 changed files with 30 additions and 83 deletions
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113
dasdinfo/dasdinfo.c
View File

@@ -23,11 +23,12 @@
#include <unistd.h>
#include "lib/util_base.h"
#include "lib/util_file.h"
#include "lib/util_opt.h"
#include "lib/util_prg.h"
#include "lib/zt_common.h"
#define READCHUNK 80
#define RD_BUFFER_SIZE 80
#define BLKSSZGET _IO(0x12,104)
#define DASD_IOCTL_LETTER 'D'
#define BIODASDINFO _IOR(DASD_IOCTL_LETTER,1,struct dasd_information)
@@ -236,29 +237,9 @@ static char *dinfo_ebcdic_dec (char *source, char *target, int l)
return target;
}
static int dinfo_read_dasd_uid (char *uidfile, char *readbuf, int readbuflen)
static int dinfo_read_dasd_uid(char *uidfile, char *readbuf)
{
FILE *dasduid;
int offset = 0;
if ((dasduid = fopen(uidfile,"r")) == NULL)
return -1;
while (fgets(readbuf + offset, READCHUNK, dasduid) &&
readbuf[strlen(readbuf)-1] != '\n' ) {
offset += READCHUNK-1;
if ( offset+READCHUNK-1 >= readbuflen ) {
readbuf = realloc(readbuf,
readbuflen + READCHUNK-1);
readbuflen += READCHUNK-1;
}
}
fclose(dasduid);
if (strlen(readbuf) <= 1)
return -1;
return 0;
return util_file_read_line(readbuf, RD_BUFFER_SIZE, uidfile);
}
static int dinfo_read_dasd_vlabel (char *device, struct volume_label *vlabel,
@@ -411,14 +392,14 @@ static void dinfo_free_devnode(char *device)
}
}
static int dinfo_extract_dev(dev_t *dev, char *str, int readbuflen)
static int dinfo_extract_dev(dev_t *dev, char *str)
{
char tmp[readbuflen];
char tmp[RD_BUFFER_SIZE];
char *p = NULL;
int ma, mi;
bzero(tmp, readbuflen);
strncpy(tmp, str, readbuflen);
bzero(tmp, RD_BUFFER_SIZE);
strncpy(tmp, str, RD_BUFFER_SIZE);
if ((p = strchr(tmp, ':')) == NULL) {
printf("Error: unable to extract major/minor\n");
return -1;
@@ -435,37 +416,17 @@ static int dinfo_extract_dev(dev_t *dev, char *str, int readbuflen)
static int dinfo_get_dev_from_blockdev(char *blockdev, dev_t *dev)
{
FILE *dasddev;
int offset = 0;
char *devfile = NULL;
char *readbuf = NULL;
int readbuflen = READCHUNK;
if ((devfile = dinfo_malloc(readbuflen)) == NULL)
return -1;
sprintf(devfile,"/sys/block/%s/dev", blockdev);
if ((readbuf = dinfo_malloc(readbuflen)) == NULL) {
readbuf = dinfo_malloc(RD_BUFFER_SIZE);
if (!readbuf) {
printf("Error: Not enough memory to allocate readbuffer\n");
return -1;
}
if ((dasddev = fopen(devfile,"r")) == NULL)
if (util_file_read_line(readbuf, RD_BUFFER_SIZE,
"/sys/block/%s/dev", blockdev) < 0)
return -1;
while (fgets(readbuf + offset, READCHUNK, dasddev) &&
readbuf[strlen(readbuf)-1] != '\n' ) {
offset += READCHUNK-1;
if (offset+READCHUNK-1 >= readbuflen) {
readbuf = realloc(readbuf,
readbuflen + READCHUNK-1);
readbuflen += READCHUNK-1;
}
}
fclose(dasddev);
if (dinfo_extract_dev(dev, readbuf, readbuflen) != 0)
if (dinfo_extract_dev(dev, readbuf) != 0)
return -1;
return 0;
@@ -580,14 +541,10 @@ out2:
static int dinfo_get_uid_from_devnode(char **uidfile, char *devnode)
{
struct stat stat_buffer;
char stat_dev[READCHUNK];
char sys_dev_path[READCHUNK];
char stat_dev[RD_BUFFER_SIZE];
char *readbuf;
DIR *directory = NULL;
struct dirent *dir_entry = NULL;
FILE *block_dev;
int readbuflen = READCHUNK;
int offset;
if (stat(devnode, &stat_buffer) != 0) {
printf("Error: could not stat %s\n", devnode);
@@ -602,29 +559,18 @@ static int dinfo_get_uid_from_devnode(char **uidfile, char *devnode)
return -1;
}
if ((readbuf = dinfo_malloc(readbuflen)) == NULL) {
readbuf = dinfo_malloc(RD_BUFFER_SIZE);
if (!readbuf) {
printf("Error: Not enough memory to allocate readbuffer\n");
return -1;
}
while ((dir_entry = readdir(directory)) != NULL) {
sprintf(sys_dev_path, "/sys/block/%s/dev", dir_entry->d_name);
if ((block_dev = fopen(sys_dev_path,"r")) == NULL)
if (util_file_read_line(readbuf, RD_BUFFER_SIZE,
"/sys/block/%s/dev",
dir_entry->d_name) < 0)
continue;
offset = 0;
while (fgets(readbuf + offset, READCHUNK, block_dev) &&
readbuf[strlen(readbuf)-1] != '\n' ) {
offset += READCHUNK-1;
if ( offset+READCHUNK-1 >= readbuflen ) {
readbuf = realloc(readbuf,
readbuflen + READCHUNK-1);
readbuflen += READCHUNK-1;
}
}
fclose(block_dev);
if (strncmp(stat_dev, readbuf,
MAX(strlen(stat_dev), strlen(readbuf)-1)) == 0) {
sprintf(*uidfile,"/sys/block/%s/device/uid",
@@ -644,7 +590,6 @@ int main(int argc, char * argv[])
char *uidfile = NULL;
char *device = NULL;
char *readbuf = NULL;
int readbuflen = READCHUNK;
dev_t dev;
int export = 0;
int c;
@@ -733,8 +678,9 @@ int main(int argc, char * argv[])
exit(1);
}
if (((readbuf = dinfo_malloc(readbuflen)) == NULL) ||
((uidfile = dinfo_malloc(readbuflen)) == NULL))
readbuf = dinfo_malloc(RD_BUFFER_SIZE);
uidfile = dinfo_malloc(RD_BUFFER_SIZE);
if (!(readbuf && uidfile))
exit(1);
/* try to read the uid attribute */
@@ -753,7 +699,7 @@ int main(int argc, char * argv[])
}
if (print_uid) {
if (dinfo_read_dasd_uid(uidfile, readbuf, readbuflen) == 0) {
if (dinfo_read_dasd_uid(uidfile, readbuf) == 0) {
/* look for the 4th '.' and cut there */
srchuid = readbuf - 1;
for (i = 0; i < 4; ++i) {
@@ -766,20 +712,20 @@ int main(int argc, char * argv[])
srchuid[1] = 0;
}
if (export) {
printf("ID_UID=%s",readbuf);
printf("ID_UID=%s\n", readbuf);
} else
printf("%s",readbuf);
printf("%s\n", readbuf);
if (!print_vlabel && !print_extended_uid)
goto out;
}
}
if (print_extended_uid) {
if (dinfo_read_dasd_uid(uidfile, readbuf, readbuflen) == 0) {
if (dinfo_read_dasd_uid(uidfile, readbuf) == 0) {
if (export) {
printf("ID_XUID=%s",readbuf);
printf("ID_XUID=%s\n", readbuf);
} else
printf("%s",readbuf);
printf("%s\n", readbuf);
if (!print_vlabel)
goto out;
}
@@ -808,7 +754,8 @@ int main(int argc, char * argv[])
goto error;
} else if (devnode) {
if ((device = dinfo_malloc(readbuflen)) == NULL)
device = dinfo_malloc(RD_BUFFER_SIZE);
if (!device)
exit(1);
strcpy(device, devnode);
}