fs: fat: structure for name and extension
The short name and extension of FAT files are stored in adjacent fields of the directory entry. For some operations like calculating a checksum or copying both fields it is preferable to treat both as one structure. Change the definition of the directory entry structure to include a structure comprising the name and the extension field. This resolves Coverity CID 316357, CID 316350, CID 316348. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Heinrich Schuchardt
parent
e97eb638de
commit
041f0af366
32
fs/fat/fat.c
32
fs/fat/fat.c
@ -123,16 +123,16 @@ static void get_name(dir_entry *dirent, char *s_name)
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{
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char *ptr;
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memcpy(s_name, dirent->name, 8);
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memcpy(s_name, dirent->nameext.name, 8);
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s_name[8] = '\0';
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ptr = s_name;
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while (*ptr && *ptr != ' ')
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ptr++;
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if (dirent->lcase & CASE_LOWER_BASE)
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downcase(s_name, (unsigned)(ptr - s_name));
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if (dirent->ext[0] && dirent->ext[0] != ' ') {
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if (dirent->nameext.ext[0] && dirent->nameext.ext[0] != ' ') {
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*ptr++ = '.';
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memcpy(ptr, dirent->ext, 3);
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memcpy(ptr, dirent->nameext.ext, 3);
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if (dirent->lcase & CASE_LOWER_EXT)
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downcase(ptr, 3);
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ptr[3] = '\0';
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@ -472,16 +472,15 @@ static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
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}
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/* Calculate short name checksum */
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static __u8 mkcksum(const char name[8], const char ext[3])
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static __u8 mkcksum(struct nameext *nameext)
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{
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int i;
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u8 *pos = (void *)nameext;
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__u8 ret = 0;
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for (i = 0; i < 8; i++)
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ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
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for (i = 0; i < 3; i++)
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ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
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for (i = 0; i < 11; i++)
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ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + pos[i];
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return ret;
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}
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@ -896,7 +895,7 @@ static dir_entry *next_dent(fat_itr *itr)
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}
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/* have we reached the last valid entry? */
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if (itr->dent->name[0] == 0)
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if (itr->dent->nameext.name[0] == 0)
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return NULL;
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return itr->dent;
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@ -905,7 +904,7 @@ static dir_entry *next_dent(fat_itr *itr)
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static dir_entry *extract_vfat_name(fat_itr *itr)
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{
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struct dir_entry *dent = itr->dent;
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int seqn = itr->dent->name[0] & ~LAST_LONG_ENTRY_MASK;
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int seqn = itr->dent->nameext.name[0] & ~LAST_LONG_ENTRY_MASK;
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u8 chksum, alias_checksum = ((dir_slot *)dent)->alias_checksum;
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int n = 0;
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@ -932,18 +931,19 @@ static dir_entry *extract_vfat_name(fat_itr *itr)
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* We are now at the short file name entry.
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* If it is marked as deleted, just skip it.
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*/
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if (dent->name[0] == DELETED_FLAG ||
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dent->name[0] == aRING)
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if (dent->nameext.name[0] == DELETED_FLAG ||
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dent->nameext.name[0] == aRING)
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return NULL;
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itr->l_name[n] = '\0';
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chksum = mkcksum(dent->name, dent->ext);
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chksum = mkcksum(&dent->nameext);
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/* checksum mismatch could mean deleted file, etc.. skip it: */
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if (chksum != alias_checksum) {
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debug("** chksum=%x, alias_checksum=%x, l_name=%s, s_name=%8s.%3s\n",
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chksum, alias_checksum, itr->l_name, dent->name, dent->ext);
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chksum, alias_checksum, itr->l_name, dent->nameext.name,
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dent->nameext.ext);
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return NULL;
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}
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@ -984,12 +984,12 @@ static int fat_itr_next(fat_itr *itr)
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itr->dent_rem = itr->remaining;
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itr->dent_start = itr->dent;
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itr->dent_clust = itr->clust;
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if (dent->name[0] == DELETED_FLAG)
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if (dent->nameext.name[0] == DELETED_FLAG)
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continue;
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if (dent->attr & ATTR_VOLUME) {
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if ((dent->attr & ATTR_VFAT) == ATTR_VFAT &&
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(dent->name[0] & LAST_LONG_ENTRY_MASK)) {
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(dent->nameext.name[0] & LAST_LONG_ENTRY_MASK)) {
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/* long file name */
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dent = extract_vfat_name(itr);
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/*
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@ -275,7 +275,7 @@ static int fat_find_empty_dentries(fat_itr *itr, int count)
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log_debug("Not enough directory entries available\n");
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return -ENOSPC;
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}
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switch (itr->dent->name[0]) {
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switch (itr->dent->nameext.name[0]) {
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case 0x00:
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case DELETED_FLAG:
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if (!n) {
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@ -399,7 +399,7 @@ fill_dir_slot(fat_itr *itr, const char *l_name, const char *shortname)
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int idx = 0, ret;
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/* Get short file name checksum value */
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checksum = mkcksum(shortname, shortname + 8);
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checksum = mkcksum((void *)shortname);
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do {
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memset(slotptr, 0x00, sizeof(dir_slot));
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@ -1169,7 +1169,7 @@ static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
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dentptr->attr = attr;
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memcpy(dentptr->name, shortname, SHORT_NAME_SIZE);
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memcpy(&dentptr->nameext, shortname, SHORT_NAME_SIZE);
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}
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/**
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@ -1194,7 +1194,7 @@ static dir_entry *find_directory_entry(fat_itr *itr, char *filename)
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if (!match)
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continue;
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if (itr->dent->name[0] == '\0')
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if (itr->dent->nameext.name[0] == '\0')
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return NULL;
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else
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return itr->dent;
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@ -1470,7 +1470,7 @@ static int delete_single_dentry(fat_itr *itr)
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struct dir_entry *dent = itr->dent;
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memset(dent, 0, sizeof(*dent));
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dent->name[0] = DELETED_FLAG;
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dent->nameext.name[0] = DELETED_FLAG;
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if (!itr->remaining)
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return flush_dir(itr);
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@ -1486,7 +1486,7 @@ static int delete_single_dentry(fat_itr *itr)
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static int delete_long_name(fat_itr *itr)
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{
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struct dir_entry *dent = itr->dent;
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int seqn = itr->dent->name[0] & ~LAST_LONG_ENTRY_MASK;
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int seqn = itr->dent->nameext.name[0] & ~LAST_LONG_ENTRY_MASK;
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while (seqn--) {
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int ret;
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@ -1531,7 +1531,7 @@ static int delete_dentry_long(fat_itr *itr)
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dent = itr->dent_start;
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/* Delete long name */
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if ((dent->attr & ATTR_VFAT) == ATTR_VFAT &&
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(dent->name[0] & LAST_LONG_ENTRY_MASK)) {
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(dent->nameext.name[0] & LAST_LONG_ENTRY_MASK)) {
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int ret;
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ret = delete_long_name(itr);
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@ -1712,12 +1712,10 @@ int fat_mkdir(const char *new_dirname)
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}
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memset(dotdent, 0, bytesperclust);
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memcpy(dotdent[0].name, ". ", 8);
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memcpy(dotdent[0].ext, " ", 3);
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memcpy(&dotdent[0].nameext, ". ", 11);
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dotdent[0].attr = ATTR_DIR | ATTR_ARCH;
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memcpy(dotdent[1].name, ".. ", 8);
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memcpy(dotdent[1].ext, " ", 3);
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memcpy(&dotdent[1].nameext, ".. ", 11);
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dotdent[1].attr = ATTR_DIR | ATTR_ARCH;
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if (itr->is_root)
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@ -132,8 +132,13 @@ typedef struct volume_info
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#define CASE_LOWER_BASE 8 /* base (name) is lower case */
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#define CASE_LOWER_EXT 16 /* extension is lower case */
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struct nameext {
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char name[8];
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char ext[3];
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};
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typedef struct dir_entry {
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char name[8],ext[3]; /* Name and extension */
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struct nameext nameext; /* Name and extension */
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__u8 attr; /* Attribute bits */
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__u8 lcase; /* Case for name and ext (CASE_LOWER_x) */
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__u8 ctime_ms; /* Creation time, milliseconds */
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