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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] Many fixes and cleanups for lomount:
# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID dfa7ba9c1296c232ceced197cee88f9d02237a68
# Parent fd102a15436fba92dd132e1fc7bbe38bb180444d
Many fixes and cleanups for lomount:
- Fixed several overflows, off-by-one, and uninitialized variables.
- Added well-defined exit codes.
- Proper handling of system()'s return value.
- Errors parsing partition table cause it to stop now.
- etcetera...
Tested on 32 and 64 bit, with valgrind, with physical disks and disk
images.
Signed-off-by: Charles Coffing <ccoffing@xxxxxxxxxx>
diff -r fd102a15436f -r dfa7ba9c1296 tools/misc/lomount/lomount.c
--- a/tools/misc/lomount/lomount.c Thu Mar 2 20:34:16 2006
+++ b/tools/misc/lomount/lomount.c Thu Mar 2 20:35:17 2006
@@ -24,16 +24,33 @@
* THE SOFTWARE.
*/
+/*
+ * Return code:
+ *
+ * bit 7 set: lomount wrapper failed
+ * bit 7 clear: lomount wrapper ok; mount's return code in low 7 bits
+ * 0 success
+ */
+
+enum
+{
+ ERR_USAGE = 0x80, // Incorrect usage
+ ERR_PART_PARSE, // Failed to parse partition table
+ ERR_NO_PART, // No such partition
+ ERR_NO_EPART, // No such extended partition
+ ERR_MOUNT // Other failure of mount command
+};
+
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
+#include <sys/wait.h>
#include <errno.h>
#define BUF 4096
-//#define SECSIZE 4096 /* arbitrarilly large (it's probably just 512) */
#define SECSIZE 512
struct pentry
@@ -50,30 +67,32 @@
unsigned long no_of_sectors_abs;
};
-char * progname;
-
-int loadptable(const char *argv, struct pentry parttbl[], struct pentry
**exttbl)
-{
- FILE *fd;
- int i, valid, total_known_sectors = 0;
+int loadptable(const char *diskimage, struct pentry parttbl[], struct pentry
**exttbl, int * valid)
+{
+ FILE *fd;
+ size_t size;
+ int fail = 1;
+ int i, total_known_sectors = 0;
unsigned char *pi;
unsigned char data [SECSIZE];
unsigned long extent = 0, old_extent = 0, e_count = 1;
struct pentry exttbls[4];
- fd = fopen(argv, "r");
+ *valid = 0;
+
+ fd = fopen(diskimage, "r");
if (fd == NULL)
{
- perror ("lomount");
- return 1;
- }
- i = fread (&data, 1, sizeof (data), fd);
- if (i < SECSIZE)
- {
- fprintf (stderr, "%s: could not read the entire first
sector\n", progname);
- return 1;
- }
- for (i = 0;i < 4;i++)
+ perror(diskimage);
+ goto done;
+ }
+ size = fread (&data, 1, sizeof(data), fd);
+ if (size < (size_t)sizeof(data))
+ {
+ fprintf(stderr, "Could not read the entire first sector of
%s.\n", diskimage);
+ goto done;
+ }
+ for (i = 0; i < 4; i++)
{
pi = &data [446 + 16 * i];
parttbl [i].bootable = *pi;
@@ -95,7 +114,7 @@
old_extent = extent;
}
}
- valid = (data [510] == 0x55 && data [511] == 0xaa) ? 1 : 0;
+ *valid = (data [510] == 0x55 && data [511] == 0xaa) ? 1 : 0;
for (i = 0; i < 4; i++)
{
total_known_sectors += parttbl[i].no_of_sectors_abs;
@@ -105,7 +124,7 @@
#ifdef DEBUG
if (extent != 0)
{
- printf("extended partition detected at offset %d\n", extent);
+ printf("extended partition detected at offset %ld\n", extent);
}
#endif
while (extent != 0)
@@ -113,14 +132,14 @@
/* according to realloc(3) passing NULL as pointer is same as calling malloc()
*/
exttbl[0] = realloc(exttbl[0], e_count * sizeof(struct pentry));
fseek(fd, extent, SEEK_SET);
- i = fread (&data, 1, sizeof (data), fd);
- if (i < SECSIZE)
- {
- fprintf (stderr, "%s: could not read the entire first
sector\n", progname);
- return 1;
+ size = fread (&data, 1, sizeof(data), fd);
+ if (size < (size_t)sizeof(data))
+ {
+ fprintf(stderr, "Could not read extended partition of
%s.", diskimage);
+ goto done;
}
/* only first 2 entrys are used in extented partition tables */
- for (i = 0;i < 2;i++)
+ for (i = 0; i < 2; i++)
{
pi = &data [446 + 16 * i];
exttbls [i].bootable = *pi;
@@ -152,7 +171,7 @@
/* adjust for start of image instead of start of ext
partition */
exttbl[0][e_count-1].start_sector_abs +=
(extent/SECSIZE);
#ifdef DEBUG
- printf("extent %d start_sector_abs %d\n",
extent, exttbl[0][e_count-1].start_sector_abs);
+ printf("extent %ld start_sector_abs %ld\n",
extent, exttbl[0][e_count-1].start_sector_abs);
#endif
//else if (parttbl[i].system == 0x5)
}
@@ -165,53 +184,71 @@
}
e_count ++;
}
- //fclose (fd);
- //the above segfaults (?!!!)
-#ifdef DEBUG
- printf("e_count = %d\n", e_count);
-#endif
- return valid;
+#ifdef DEBUG
+ printf("e_count = %ld\n", e_count);
+#endif
+ fail = 0;
+
+done:
+ if (fd)
+ fclose(fd);
+ return fail;
}
+void usage()
+{
+ fprintf(stderr, "You must specify at least -diskimage and
-partition.\n");
+ fprintf(stderr, "All other arguments are passed through to 'mount'.\n");
+ fprintf(stderr, "ex. lomount -t fs-type -diskimage hda.img -partition 1
/mnt\n");
+ exit(ERR_USAGE);
+}
+
int main(int argc, char ** argv)
{
+ int status;
struct pentry perttbl [4];
struct pentry *exttbl[1], *parttbl;
- char buf[BUF], argv2[BUF], diskimage[BUF];
- int partition = 1, sec, num = 0, pnum = 0, len = BUF, i, f = 0, valid;
- progname = argv[0];
+ char buf[BUF], argv2[BUF];
+ const char * diskimage = 0;
+ int partition = 0, sec, num = 0, pnum = 0, i, valid;
+ size_t argv2_len = sizeof(argv2);
+ argv2[0] = '\0';
exttbl[0] = NULL;
+
for (i = 1; i < argc; i ++)
{
- if (strncmp(argv[i], "-diskimage", BUF)==0)
- {
- strncpy(diskimage, argv[i+1], BUF);
- i++; f = 1;
- }
- else if (strncmp(argv[i], "-partition", BUF)==0)
- {
- partition = atoi(argv[i+1]);
+ if (strcmp(argv[i], "-diskimage")==0)
+ {
+ if (i == argc-1)
+ usage();
i++;
- if (partition < 1) partition = 1;
+ diskimage = argv[i];
+ }
+ else if (strcmp(argv[i], "-partition")==0)
+ {
+ if (i == argc-1)
+ usage();
+ i++;
+ partition = atoi(argv[i]);
}
else
{
- strncat(argv2, argv[i], len);
- strncat(argv2, " ", len-1);
- len -= strlen(argv[i]);
- len--;
- }
- }
- if (!f)
- {
- printf("You must specify -diskimage and -partition\n");
- printf("ex. lomount -t fs-type -diskimage hda.img -partition 1
/mnt\n");
- return 0;
- }
- valid = loadptable(diskimage, perttbl, exttbl);
+ size_t len = strlen(argv[i]);
+ if (len >= argv2_len-1)
+ usage();
+ strcat(argv2, argv[i]);
+ strcat(argv2, " ");
+ len -= (len+1);
+ }
+ }
+ if (! diskimage || partition < 1)
+ usage();
+
+ if (loadptable(diskimage, perttbl, exttbl, &valid))
+ return ERR_PART_PARSE;
if (!valid)
{
- printf("Warning: disk image does not appear to describe a valid
partition table.\n");
+ fprintf(stderr, "Warning: disk image does not appear to
describe a valid partition table.\n");
}
/* NOTE: need to make sure this always rounds down */
//sec = total_known_sectors / sizeof_diskimage;
@@ -228,14 +265,14 @@
{
if (exttbl[0] == NULL)
{
- printf("No extended partitions were found in %s.\n",
diskimage);
- return 2;
+ fprintf(stderr, "No extended partitions were found in
%s.\n", diskimage);
+ return ERR_NO_EPART;
}
parttbl = exttbl[0];
if (parttbl[partition-5].no_of_sectors_abs == 0)
{
- printf("Partition %d was not found in %s.\n",
partition, diskimage);
- return 3;
+ fprintf(stderr, "Partition %d was not found in %s.\n",
partition, diskimage);
+ return ERR_NO_PART;
}
partition -= 4;
}
@@ -244,8 +281,8 @@
parttbl = perttbl;
if (parttbl[partition-1].no_of_sectors_abs == 0)
{
- printf("Partition %d was not found in %s.\n",
partition, diskimage);
- return 3;
+ fprintf(stderr, "Partition %d was not found in %s.\n",
partition, diskimage);
+ return ERR_NO_PART;
}
}
num = parttbl[partition-1].start_sector_abs;
@@ -253,10 +290,14 @@
#ifdef DEBUG
printf("offset = %d\n", pnum);
#endif
- snprintf(buf, BUF, "mount -oloop,offset=%d %s %s", pnum, diskimage,
argv2);
+ snprintf(buf, sizeof(buf), "mount -oloop,offset=%d %s %s", pnum,
diskimage, argv2);
#ifdef DEBUG
printf("%s\n", buf);
#endif
- system(buf);
- return 0;
+ status = system(buf);
+ if (WIFEXITED(status))
+ status = WEXITSTATUS(status);
+ else
+ status = ERR_MOUNT;
+ return status;
}
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