blockdev.c: getsize(): signed args, error checking

[Stefan Krah]

Hello,

in getsize() the BLKGETSIZE and BLKGETSIZE64 ioctls are called
with signed args, see the patch below.


Another thing:

Since the EFBIG change in getsize() sz might contain garbage, so there
should be additional error checks, something like (yes, this is ugly):


static int
getsize(int fd, unsigned long long *sectors) {
        int err1, err2;
        unsigned long sz;
        unsigned long long b;

        err1 = ioctl (fd, BLKGETSIZE, &sz);
        if (err1) {
                if (errno != EFBIG)
                        return err1;
        }
        err2 = ioctl(fd, BLKGETSIZE64, &b);
        if (!err1 && (err2 || b == 0 || b == sz))
                *sectors = sz;
        else if (!err2)
                *sectors = (b >> 9);
        else
                return err2;

        return 0;
}


What is the purpose of (b == 0 || b == sz)? I searched a little and most
getsize() functions seem to try BLKGETSIZE64 first. If that fails, they
try other methods.


Stefan Krah




========================================================================

diff --git a/disk-utils/blockdev.c b/disk-utils/blockdev.c
index d02ebbc..d0ddb1b 100644
--- a/disk-utils/blockdev.c
+++ b/disk-utils/blockdev.c
@@ -145,10 +145,10 @@ find_cmd(char *s) {
 }
 
 static int
-getsize(int fd, long long *sectors) {
+getsize(int fd, unsigned long long *sectors) {
        int err;
-       long sz;
-       long long b;
+       unsigned long sz;
+       unsigned long long b;
 
        err = ioctl (fd, BLKGETSIZE, &sz);
        if (err) {
@@ -262,9 +262,9 @@ do_commands(int fd, char **argv, int d) {
                }
 
                if (!strcmp(argv[i], "--getsz")) {
-                       res = getsize(fd, &llarg);
+                       res = getsize(fd, &llu);
                        if (res == 0)
-                               printf("%lld\n", llarg);
+                               printf("%llu\n", llu);
                        else
                                exit(1);
                        continue;
@@ -401,7 +401,7 @@ report_device(char *device, int quiet) {
        int fd;
        int ro, ssz, bsz;
        long ra, ss;
-       long long bytes;
+       unsigned long long sectors;
        struct hd_geometry g;
 
        fd = open(device, O_RDONLY | O_NONBLOCK);
@@ -419,9 +419,9 @@ report_device(char *device, int quiet) {
            ioctl (fd, BLKSSZGET, &ssz) == 0 &&
            ioctl (fd, BLKBSZGET, &bsz) == 0 &&
            ioctl (fd, HDIO_GETGEO, &g) == 0 &&
-           getsize (fd, &bytes) == 0) {
-               printf("%s %5ld %5d %5d %10ld %10lld  %s\n",
-                      ro ? "ro" : "rw", ra, ssz, bsz, g.start, bytes, device);
+           getsize (fd, &sectors) == 0) {
+               printf("%s %5ld %5d %5d %10ld %10llu  %s\n",
+                      ro ? "ro" : "rw", ra, ssz, bsz, g.start, sectors, 
device);
        } else {
                if (!quiet)
                        fprintf(stderr, _("%s: ioctl error on %s\n"),


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