volume_id/fat: careful with sector#, it may not fit in 32 bits. +91 bytes

volume_id/*: a bit of code shrink
This commit is contained in:
Denis Vlasenko 2008-11-30 17:41:31 +00:00
parent a34b8a4d30
commit 1e10afcdfb
3 changed files with 68 additions and 66 deletions

View File

@ -245,7 +245,7 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t fat_partition_off)
buf_size = dir_entries * sizeof(struct vfat_dir_entry); buf_size = dir_entries * sizeof(struct vfat_dir_entry);
buf = volume_id_get_buffer(id, fat_partition_off + root_start_off, buf_size); buf = volume_id_get_buffer(id, fat_partition_off + root_start_off, buf_size);
if (buf == NULL) if (buf == NULL)
goto found; goto ret;
label = get_attr_volume_id((struct vfat_dir_entry*) buf, dir_entries); label = get_attr_volume_id((struct vfat_dir_entry*) buf, dir_entries);
@ -261,7 +261,7 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t fat_partition_off)
volume_id_set_label_string(id, vs->type.fat.label, 11); volume_id_set_label_string(id, vs->type.fat.label, 11);
} }
volume_id_set_uuid(id, vs->type.fat.serno, UUID_DOS); volume_id_set_uuid(id, vs->type.fat.serno, UUID_DOS);
goto found; goto ret;
fat32: fat32:
/* FAT32 root dir is a cluster chain like any other directory */ /* FAT32 root dir is a cluster chain like any other directory */
@ -272,20 +272,20 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t fat_partition_off)
next_cluster = root_cluster; next_cluster = root_cluster;
maxloop = 100; maxloop = 100;
while (--maxloop) { while (--maxloop) {
uint32_t next_off_sct; uint64_t next_off_sct;
uint64_t next_off; uint64_t next_off;
uint64_t fat_entry_off; uint64_t fat_entry_off;
int count; int count;
dbg("next_cluster 0x%x", (unsigned)next_cluster); dbg("next_cluster 0x%x", (unsigned)next_cluster);
next_off_sct = (next_cluster - 2) * vs->sectors_per_cluster; next_off_sct = (uint64_t)(next_cluster - 2) * vs->sectors_per_cluster;
next_off = (start_data_sct + next_off_sct) * sector_size_bytes; next_off = (start_data_sct + next_off_sct) * sector_size_bytes;
dbg("cluster offset 0x%llx", (unsigned long long) next_off); dbg("cluster offset 0x%llx", (unsigned long long) next_off);
/* get cluster */ /* get cluster */
buf = volume_id_get_buffer(id, fat_partition_off + next_off, buf_size); buf = volume_id_get_buffer(id, fat_partition_off + next_off, buf_size);
if (buf == NULL) if (buf == NULL)
goto found; goto ret;
dir = (struct vfat_dir_entry*) buf; dir = (struct vfat_dir_entry*) buf;
count = buf_size / sizeof(struct vfat_dir_entry); count = buf_size / sizeof(struct vfat_dir_entry);
@ -300,7 +300,7 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t fat_partition_off)
dbg("fat_entry_off 0x%llx", (unsigned long long)fat_entry_off); dbg("fat_entry_off 0x%llx", (unsigned long long)fat_entry_off);
buf = volume_id_get_buffer(id, fat_partition_off + fat_entry_off, buf_size); buf = volume_id_get_buffer(id, fat_partition_off + fat_entry_off, buf_size);
if (buf == NULL) if (buf == NULL)
goto found; goto ret;
/* set next cluster */ /* set next cluster */
next_cluster = le32_to_cpu(*(uint32_t*)buf) & 0x0fffffff; next_cluster = le32_to_cpu(*(uint32_t*)buf) & 0x0fffffff;
@ -323,7 +323,7 @@ int volume_id_probe_vfat(struct volume_id *id, uint64_t fat_partition_off)
} }
volume_id_set_uuid(id, vs->type.fat32.serno, UUID_DOS); volume_id_set_uuid(id, vs->type.fat32.serno, UUID_DOS);
found: ret:
// volume_id_set_usage(id, VOLUME_ID_FILESYSTEM); // volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
// id->type = "vfat"; // id->type = "vfat";

View File

@ -195,70 +195,73 @@ set:
* It's better to ignore such fs and continue. */ * It's better to ignore such fs and continue. */
void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len) void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
{ {
ssize_t buf_len; uint8_t *dst;
unsigned small_off;
ssize_t read_len;
dbg("get buffer off 0x%llx(%llu), len 0x%zx",
(unsigned long long) off, (unsigned long long) off, len);
dbg("get buffer off 0x%llx(%llu), len 0x%zx", (unsigned long long) off, (unsigned long long) off, len);
/* check if requested area fits in superblock buffer */ /* check if requested area fits in superblock buffer */
if (off + len <= SB_BUFFER_SIZE) { if (off + len <= SB_BUFFER_SIZE
/* && off <= SB_BUFFER_SIZE - want this paranoid overflow check? */
) {
if (id->sbbuf == NULL) { if (id->sbbuf == NULL) {
id->sbbuf = xmalloc(SB_BUFFER_SIZE); id->sbbuf = xmalloc(SB_BUFFER_SIZE);
} }
small_off = off;
dst = id->sbbuf;
/* check if we need to read */ /* check if we need to read */
if ((off + len) > id->sbbuf_len) { len += off;
dbg("read sbbuf len:0x%llx", (unsigned long long) (off + len)); if (len <= id->sbbuf_len)
if (lseek(id->fd, 0, SEEK_SET) != 0) { goto ret; /* we already have it */
dbg("seek(0) failed");
return NULL;
}
buf_len = full_read(id->fd, id->sbbuf, off + len);
if (buf_len < 0) {
dbg("read failed (%s)", strerror(errno));
return NULL;
}
dbg("got 0x%zx (%zi) bytes", buf_len, buf_len);
id->sbbuf_len = buf_len;
if ((uint64_t)buf_len < off + len) {
dbg("requested 0x%zx bytes, got only 0x%zx bytes", len, buf_len);
return NULL;
}
}
return &(id->sbbuf[off]); dbg("read sbbuf len:0x%x", (unsigned) len);
id->sbbuf_len = len;
off = 0;
goto do_read;
} }
if (len > SEEK_BUFFER_SIZE) { if (len > SEEK_BUFFER_SIZE) {
dbg("seek buffer too small %d", SEEK_BUFFER_SIZE); dbg("seek buffer too small %d", SEEK_BUFFER_SIZE);
return NULL; return NULL;
} }
dst = id->seekbuf;
/* get seek buffer */
if (id->seekbuf == NULL) {
id->seekbuf = xmalloc(SEEK_BUFFER_SIZE);
}
/* check if we need to read */ /* check if we need to read */
if ((off < id->seekbuf_off) || ((off + len) > (id->seekbuf_off + id->seekbuf_len))) { if ((off >= id->seekbuf_off)
dbg("read seekbuf off:0x%llx len:0x%zx", (unsigned long long) off, len); && ((off + len) <= (id->seekbuf_off + id->seekbuf_len))
if (lseek(id->fd, off, SEEK_SET) != off) { ) {
dbg("seek(0x%llx) failed", (unsigned long long) off); small_off = off - id->seekbuf_off; /* can't overflow */
return NULL; goto ret; /* we already have it */
}
buf_len = full_read(id->fd, id->seekbuf, len);
if (buf_len < 0) {
dbg("read failed (%s)", strerror(errno));
return NULL;
}
dbg("got 0x%zx (%zi) bytes", buf_len, buf_len);
id->seekbuf_off = off;
id->seekbuf_len = buf_len;
if ((size_t)buf_len < len) {
dbg("requested 0x%zx bytes, got only 0x%zx bytes", len, buf_len);
return NULL;
}
} }
return &(id->seekbuf[off - id->seekbuf_off]); id->seekbuf_off = off;
id->seekbuf_len = len;
id->seekbuf = xrealloc(id->seekbuf, len);
small_off = 0;
dst = id->seekbuf;
dbg("read seekbuf off:0x%llx len:0x%zx",
(unsigned long long) off, len);
do_read:
if (lseek(id->fd, off, SEEK_SET) != off) {
dbg("seek(0x%llx) failed", (unsigned long long) off);
goto err;
}
read_len = full_read(id->fd, dst, len);
if (read_len != len) {
dbg("requested 0x%x bytes, got 0x%x bytes",
(unsigned) len, (unsigned) read_len);
err:
/* id->seekbuf_len or id->sbbuf_len is wrong now! Fixing.
* Most likely user will not do any additional
* calls anyway, it's a corrupted fs or something. */
volume_id_free_buffer(id);
return NULL;
}
ret:
return dst + small_off;
} }
void volume_id_free_buffer(struct volume_id *id) void volume_id_free_buffer(struct volume_id *id)
@ -269,4 +272,5 @@ void volume_id_free_buffer(struct volume_id *id)
free(id->seekbuf); free(id->seekbuf);
id->seekbuf = NULL; id->seekbuf = NULL;
id->seekbuf_len = 0; id->seekbuf_len = 0;
id->seekbuf_off = 0; /* paranoia */
} }

View File

@ -61,6 +61,17 @@ struct volume_id_partition {
#endif #endif
struct volume_id { struct volume_id {
int fd;
// int fd_close:1;
size_t sbbuf_len;
size_t seekbuf_len;
uint8_t *sbbuf;
uint8_t *seekbuf;
uint64_t seekbuf_off;
#ifdef UNUSED_PARTITION_CODE
struct volume_id_partition *partitions;
size_t partition_count;
#endif
// uint8_t label_raw[VOLUME_ID_LABEL_SIZE]; // uint8_t label_raw[VOLUME_ID_LABEL_SIZE];
// size_t label_raw_len; // size_t label_raw_len;
char label[VOLUME_ID_LABEL_SIZE+1]; char label[VOLUME_ID_LABEL_SIZE+1];
@ -72,19 +83,6 @@ struct volume_id {
// smallint usage_id; // smallint usage_id;
// const char *usage; // const char *usage;
// const char *type; // const char *type;
#ifdef UNUSED_PARTITION_CODE
struct volume_id_partition *partitions;
size_t partition_count;
#endif
int fd;
uint8_t *sbbuf;
uint8_t *seekbuf;
size_t sbbuf_len;
uint64_t seekbuf_off;
size_t seekbuf_len;
// int fd_close:1;
}; };
struct volume_id *volume_id_open_node(int fd); struct volume_id *volume_id_open_node(int fd);