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Diffstat (limited to 'libblkid/probe.c')
| -rw-r--r-- | libblkid/probe.c | 1779 |
1 files changed, 1779 insertions, 0 deletions
diff --git a/libblkid/probe.c b/libblkid/probe.c new file mode 100644 index 000000000..77e8b860c --- /dev/null +++ b/libblkid/probe.c @@ -0,0 +1,1779 @@ +/* + * Low-level libblkid probing API + * + * Copyright (C) 2008-2009 Karel Zak <kzak@redhat.com> + * + * This file may be redistributed under the terms of the + * GNU Lesser General Public License. + */ + +/** + * SECTION: lowprobe + * @title: Low-level probing + * @short_description: low-level prober initialization + * + * The low-level probing routines always and directly read information from + * the selected (see blkid_probe_set_device()) device. + * + * The probing routines are grouped together into separate chains. Currently, + * the library provides superblocks, partitions and topology chains. + * + * The probing routines is possible to filter (enable/disable) by type (e.g. + * fstype "vfat" or partype "gpt") or by usage flags (e.g. BLKID_USAGE_RAID). + * These filters are per-chain. Note that always when you touch the chain + * filter the current probing position is reset and probing starts from + * scratch. It means that the chain filter should not be modified during + * probing, for example in loop where you call blkid_do_probe(). + * + * For more details see the chain specific documentation. + * + * The low-level API provides two ways how access to probing results. + * + * 1. The NAME=value (tag) interface. This interface is older and returns all data + * as strings. This interface is generic for all chains. + * + * 2. The binary interfaces. These interfaces return data in the native formats. + * The interface is always specific to the probing chain. + * + * Note that the previous probing result (binary or NAME=value) is always + * zeroized when a chain probing function is called. For example: + * + * <informalexample> + * <programlisting> + * blkid_probe_enable_partitions(pr, TRUE); + * blkid_probe_enable_superblocks(pr, FALSE); + * + * blkid_do_safeprobe(pr); + * </programlisting> + * </informalexample> + * + * overwrites the previous probing result for the partitions chain, the superblocks + * result is not modified. + */ + +/** + * SECTION: lowprobe-tags + * @title: Low-level tags + * @short_description: generic NAME=value interface. + * + * The probing routines inside the chain are mutually exclusive by default -- + * only few probing routines are marked as "tolerant". The "tolerant" probing + * routines are used for filesystem which can share the same device with any + * other filesystem. The blkid_do_safeprobe() checks for the "tolerant" flag. + * + * The SUPERBLOCKS chain is enabled by default. The all others chains is + * necessary to enable by blkid_probe_enable_'CHAINNAME'(). See chains specific + * documentation. + * + * The blkid_do_probe() function returns a result from only one probing + * routine, and the next call from the next probing routine. It means you need + * to call the function in loop, for example: + * + * <informalexample> + * <programlisting> + * while((blkid_do_probe(pr) == 0) + * ... use result ... + * </programlisting> + * </informalexample> + * + * The blkid_do_safeprobe() is the same as blkid_do_probe(), but returns only + * first probing result for every enabled chain. This function checks for + * ambivalent results (e.g. more "intolerant" filesystems superblocks on the + * device). + * + * The probing result is set of NAME=value pairs (the NAME is always unique). + */ + +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <unistd.h> +#include <fcntl.h> +#include <ctype.h> +#include <sys/types.h> +#ifdef HAVE_LINUX_CDROM_H +#include <linux/cdrom.h> +#endif +#ifdef HAVE_SYS_STAT_H +#include <sys/stat.h> +#endif +#ifdef HAVE_ERRNO_H +#include <errno.h> +#endif +#include <inttypes.h> +#include <stdint.h> +#include <stdarg.h> + +#ifdef HAVE_LIBUUID +# include <uuid.h> +#endif + +#include "blkidP.h" +#include "all-io.h" + +/* chains */ +extern const struct blkid_chaindrv superblocks_drv; +extern const struct blkid_chaindrv topology_drv; +extern const struct blkid_chaindrv partitions_drv; + +/* + * All supported chains + */ +static const struct blkid_chaindrv *chains_drvs[] = { + [BLKID_CHAIN_SUBLKS] = &superblocks_drv, + [BLKID_CHAIN_TOPLGY] = &topology_drv, + [BLKID_CHAIN_PARTS] = &partitions_drv +}; + +static void blkid_probe_reset_vals(blkid_probe pr); +static void blkid_probe_reset_buffer(blkid_probe pr); + +/** + * blkid_new_probe: + * + * Returns: a pointer to the newly allocated probe struct or NULL in case of error. + */ +blkid_probe blkid_new_probe(void) +{ + int i; + blkid_probe pr; + + blkid_init_debug(0); + pr = calloc(1, sizeof(struct blkid_struct_probe)); + if (!pr) + return NULL; + + DBG(DEBUG_LOWPROBE, printf("allocate a new probe %p\n", pr)); + + /* initialize chains */ + for (i = 0; i < BLKID_NCHAINS; i++) { + pr->chains[i].driver = chains_drvs[i]; + pr->chains[i].flags = chains_drvs[i]->dflt_flags; + pr->chains[i].enabled = chains_drvs[i]->dflt_enabled; + } + INIT_LIST_HEAD(&pr->buffers); + return pr; +} + +/* + * Clone @parent, the new clone shares all, but except: + * + * - probing result + * - bufferes if another device (or offset) is set to the prober + */ +blkid_probe blkid_clone_probe(blkid_probe parent) +{ + blkid_probe pr; + + if (!parent) + return NULL; + + DBG(DEBUG_LOWPROBE, printf("allocate a probe clone\n")); + + pr = blkid_new_probe(); + if (!pr) + return NULL; + + pr->fd = parent->fd; + pr->off = parent->off; + pr->size = parent->size; + pr->devno = parent->devno; + pr->disk_devno = parent->disk_devno; + pr->blkssz = parent->blkssz; + pr->flags = parent->flags; + pr->parent = parent; + + pr->flags &= ~BLKID_FL_PRIVATE_FD; + + return pr; +} + + + +/** + * blkid_new_probe_from_filename: + * @filename: device or regular file + * + * This function is same as call open(filename), blkid_new_probe() and + * blkid_probe_set_device(pr, fd, 0, 0). + * + * The @filename is closed by blkid_free_probe() or by the + * blkid_probe_set_device() call. + * + * Returns: a pointer to the newly allocated probe struct or NULL in case of + * error. + */ +blkid_probe blkid_new_probe_from_filename(const char *filename) +{ + int fd = -1; + blkid_probe pr = NULL; + + if (!filename) + return NULL; + + fd = open(filename, O_RDONLY|O_CLOEXEC); + if (fd < 0) + return NULL; + + pr = blkid_new_probe(); + if (!pr) + goto err; + + if (blkid_probe_set_device(pr, fd, 0, 0)) + goto err; + + pr->flags |= BLKID_FL_PRIVATE_FD; + return pr; +err: + if (fd >= 0) + close(fd); + blkid_free_probe(pr); + return NULL; +} + +/** + * blkid_free_probe: + * @pr: probe + * + * Deallocates the probe struct, buffers and all allocated + * data that are associated with this probing control struct. + */ +void blkid_free_probe(blkid_probe pr) +{ + int i; + + if (!pr) + return; + + for (i = 0; i < BLKID_NCHAINS; i++) { + struct blkid_chain *ch = &pr->chains[i]; + + if (ch->driver->free_data) + ch->driver->free_data(pr, ch->data); + free(ch->fltr); + } + + if ((pr->flags & BLKID_FL_PRIVATE_FD) && pr->fd >= 0) + close(pr->fd); + blkid_probe_reset_buffer(pr); + blkid_free_probe(pr->disk_probe); + + DBG(DEBUG_LOWPROBE, printf("free probe %p\n", pr)); + free(pr); +} + + +/* + * Removes chain values from probing result. + */ +void blkid_probe_chain_reset_vals(blkid_probe pr, struct blkid_chain *chn) +{ + int nvals = pr->nvals; + int i, x; + + for (x = 0, i = 0; i < pr->nvals; i++) { + struct blkid_prval *v = &pr->vals[i]; + + if (v->chain != chn && x == i) { + x++; + continue; + } + if (v->chain == chn) { + --nvals; + continue; + } + memcpy(&pr->vals[x++], v, sizeof(struct blkid_prval)); + } + pr->nvals = nvals; +} + +static void blkid_probe_chain_reset_position(struct blkid_chain *chn) +{ + if (chn) + chn->idx = -1; +} + +/* + * Copies chain values from probing result to @vals, the max size of @vals is + * @nvals and returns real number of values. + */ +int blkid_probe_chain_copy_vals(blkid_probe pr, struct blkid_chain *chn, + struct blkid_prval *vals, int nvals) +{ + int i, x; + + for (x = 0, i = 0; i < pr->nvals && x < nvals; i++) { + struct blkid_prval *v = &pr->vals[i]; + + if (v->chain != chn) + continue; + memcpy(&vals[x++], v, sizeof(struct blkid_prval)); + } + return x; +} + +/* + * Appends values from @vals to the probing result + */ +void blkid_probe_append_vals(blkid_probe pr, struct blkid_prval *vals, int nvals) +{ + int i = 0; + + while (i < nvals && pr->nvals < BLKID_NVALS) { + memcpy(&pr->vals[pr->nvals++], &vals[i++], + sizeof(struct blkid_prval)); + } +} + +static void blkid_probe_reset_vals(blkid_probe pr) +{ + memset(pr->vals, 0, sizeof(pr->vals)); + pr->nvals = 0; +} + +struct blkid_chain *blkid_probe_get_chain(blkid_probe pr) +{ + return pr->cur_chain; +} + +void *blkid_probe_get_binary_data(blkid_probe pr, struct blkid_chain *chn) +{ + int rc, org_prob_flags; + struct blkid_chain *org_chn; + + if (!pr || !chn) + return NULL; + + /* save the current setting -- the binary API has to be completely + * independent on the current probing status + */ + org_chn = pr->cur_chain; + org_prob_flags = pr->prob_flags; + + pr->cur_chain = chn; + pr->prob_flags = 0; + chn->binary = TRUE; + blkid_probe_chain_reset_position(chn); + + rc = chn->driver->probe(pr, chn); + + chn->binary = FALSE; + blkid_probe_chain_reset_position(chn); + + /* restore the original setting + */ + pr->cur_chain = org_chn; + pr->prob_flags = org_prob_flags; + + if (rc != 0) + return NULL; + + DBG(DEBUG_LOWPROBE, + printf("returning %s binary data\n", chn->driver->name)); + return chn->data; +} + + +/** + * blkid_reset_probe: + * @pr: probe + * + * Zeroize probing results and resets the current probing (this has impact to + * blkid_do_probe() only). This function does not touch probing filters and + * keeps assigned device. + */ +void blkid_reset_probe(blkid_probe pr) +{ + int i; + + if (!pr) + return; + + blkid_probe_reset_vals(pr); + blkid_probe_set_wiper(pr, 0, 0); + + pr->cur_chain = NULL; + + for (i = 0; i < BLKID_NCHAINS; i++) + blkid_probe_chain_reset_position(&pr->chains[i]); +} + +/*** +static int blkid_probe_dump_filter(blkid_probe pr, int chain) +{ + struct blkid_chain *chn; + int i; + + if (!pr || chain < 0 || chain >= BLKID_NCHAINS) + return -1; + + chn = &pr->chains[chain]; + + if (!chn->fltr) + return -1; + + for (i = 0; i < chn->driver->nidinfos; i++) { + const struct blkid_idinfo *id = chn->driver->idinfos[i]; + + DBG(DEBUG_LOWPROBE, printf("%d: %s: %s\n", + i, + id->name, + blkid_bmp_get_item(chn->fltr, i) + ? "disabled" : "enabled <--")); + } + return 0; +} +***/ + +/* + * Returns properly initialized chain filter + */ +unsigned long *blkid_probe_get_filter(blkid_probe pr, int chain, int create) +{ + struct blkid_chain *chn; + + if (!pr || chain < 0 || chain >= BLKID_NCHAINS) + return NULL; + + chn = &pr->chains[chain]; + + /* always when you touch the chain filter all indexes are reset and + * probing starts from scratch + */ + blkid_probe_chain_reset_position(chn); + pr->cur_chain = NULL; + + if (!chn->driver->has_fltr || (!chn->fltr && !create)) + return NULL; + + if (!chn->fltr) + chn->fltr = calloc(1, blkid_bmp_nbytes(chn->driver->nidinfos)); + else + memset(chn->fltr, 0, blkid_bmp_nbytes(chn->driver->nidinfos)); + + /* blkid_probe_dump_filter(pr, chain); */ + return chn->fltr; +} + +/* + * Generic private functions for filter setting + */ +int __blkid_probe_invert_filter(blkid_probe pr, int chain) +{ + size_t i; + struct blkid_chain *chn; + + if (!pr) + return -1; + + chn = &pr->chains[chain]; + + if (!chn->driver->has_fltr || !chn->fltr) + return -1; + + for (i = 0; i < blkid_bmp_nwords(chn->driver->nidinfos); i++) + chn->fltr[i] = ~chn->fltr[i]; + + DBG(DEBUG_LOWPROBE, printf("probing filter inverted\n")); + /* blkid_probe_dump_filter(pr, chain); */ + return 0; +} + +int __blkid_probe_reset_filter(blkid_probe pr, int chain) +{ + return blkid_probe_get_filter(pr, chain, FALSE) ? 0 : -1; +} + +int __blkid_probe_filter_types(blkid_probe pr, int chain, int flag, char *names[]) +{ + unsigned long *fltr; + struct blkid_chain *chn; + size_t i; + + fltr = blkid_probe_get_filter(pr, chain, TRUE); + if (!fltr) + return -1; + + chn = &pr->chains[chain]; + + for (i = 0; i < chn->driver->nidinfos; i++) { + int has = 0; + const struct blkid_idinfo *id = chn->driver->idinfos[i]; + char **n; + + for (n = names; *n; n++) { + if (!strcmp(id->name, *n)) { + has = 1; + break; + } + } + if (flag & BLKID_FLTR_ONLYIN) { + if (!has) + blkid_bmp_set_item(fltr, i); + } else if (flag & BLKID_FLTR_NOTIN) { + if (has) + blkid_bmp_set_item(fltr, i); + } + } + + DBG(DEBUG_LOWPROBE, + printf("%s: a new probing type-filter initialized\n", + chn->driver->name)); + /* blkid_probe_dump_filter(pr, chain); */ + return 0; +} + +unsigned char *blkid_probe_get_buffer(blkid_probe pr, + blkid_loff_t off, blkid_loff_t len) +{ + struct list_head *p; + struct blkid_bufinfo *bf = NULL; + + if (pr->size <= 0) + return NULL; + + if (pr->parent && + pr->parent->devno == pr->devno && + pr->parent->off <= pr->off && + pr->parent->off + pr->parent->size >= pr->off + pr->size) { + /* + * This is a cloned prober and points to the same area as + * parent. Let's use parent's buffers. + * + * Note that pr->off (and pr->parent->off) is always from the + * beginig of the device. + */ + return blkid_probe_get_buffer(pr->parent, + pr->off + off - pr->parent->off, len); + } + + list_for_each(p, &pr->buffers) { + struct blkid_bufinfo *x = + list_entry(p, struct blkid_bufinfo, bufs); + + if (x->off <= off && off + len <= x->off + x->len) { + DBG(DEBUG_LOWPROBE, + printf("\treuse buffer: off=%jd len=%jd pr=%p\n", + x->off, x->len, pr)); + bf = x; + break; + } + } + if (!bf) { + ssize_t ret; + + if (blkid_llseek(pr->fd, pr->off + off, SEEK_SET) < 0) + return NULL; + + /* allocate info and space for data by why call */ + bf = calloc(1, sizeof(struct blkid_bufinfo) + len); + if (!bf) + return NULL; + + bf->data = ((unsigned char *) bf) + sizeof(struct blkid_bufinfo); + bf->len = len; + bf->off = off; + INIT_LIST_HEAD(&bf->bufs); + + DBG(DEBUG_LOWPROBE, + printf("\tbuffer read: off=%jd len=%jd pr=%p\n", + off, len, pr)); + + ret = read(pr->fd, bf->data, len); + if (ret != (ssize_t) len) { + free(bf); + return NULL; + } + list_add_tail(&bf->bufs, &pr->buffers); + } + + return off ? bf->data + (off - bf->off) : bf->data; +} + + +static void blkid_probe_reset_buffer(blkid_probe pr) +{ + uint64_t read_ct = 0, len_ct = 0; + + if (!pr || list_empty(&pr->buffers)) + return; + + DBG(DEBUG_LOWPROBE, printf("reseting probing buffers pr=%p\n", pr)); + + while (!list_empty(&pr->buffers)) { + struct blkid_bufinfo *bf = list_entry(pr->buffers.next, + struct blkid_bufinfo, bufs); + read_ct++; + len_ct += bf->len; + list_del(&bf->bufs); + free(bf); + } + + DBG(DEBUG_LOWPROBE, + printf("buffers summary: %"PRIu64" bytes " + "by %"PRIu64" read() call(s)\n", + len_ct, read_ct)); + + INIT_LIST_HEAD(&pr->buffers); +} + +/* + * Small devices need a special care. + */ +int blkid_probe_is_tiny(blkid_probe pr) +{ + return pr && (pr->flags & BLKID_FL_TINY_DEV); +} + +/* + * CDROMs may fail when probed for RAID (last sector problem) + */ +int blkid_probe_is_cdrom(blkid_probe pr) +{ + return pr && (pr->flags & BLKID_FL_CDROM_DEV); +} + +/** + * blkid_probe_set_device: + * @pr: probe + * @fd: device file descriptor + * @off: begin of probing area + * @size: size of probing area (zero means whole device/file) + * + * Assigns the device to probe control struct, resets internal buffers and + * resets the current probing. + * + * Returns: -1 in case of failure, or 0 on success. + */ +int blkid_probe_set_device(blkid_probe pr, int fd, + blkid_loff_t off, blkid_loff_t size) +{ + struct stat sb; + + if (!pr) + return -1; + + blkid_reset_probe(pr); + blkid_probe_reset_buffer(pr); + + if ((pr->flags & BLKID_FL_PRIVATE_FD) && pr->fd >= 0) + close(pr->fd); + + pr->flags &= ~BLKID_FL_PRIVATE_FD; + pr->flags &= ~BLKID_FL_TINY_DEV; + pr->flags &= ~BLKID_FL_CDROM_DEV; + pr->prob_flags = 0; + pr->fd = fd; + pr->off = off; + pr->size = 0; + pr->devno = 0; + pr->disk_devno = 0; + pr->mode = 0; + pr->blkssz = 0; + pr->wipe_off = 0; + pr->wipe_size = 0; + pr->wipe_chain = NULL; + +#if defined(POSIX_FADV_RANDOM) && defined(HAVE_POSIX_FADVISE) + /* Disable read-ahead */ + posix_fadvise(fd, 0, 0, POSIX_FADV_RANDOM); +#endif + if (fstat(fd, &sb)) + goto err; + + if (!S_ISBLK(sb.st_mode) && !S_ISCHR(sb.st_mode) && !S_ISREG(sb.st_mode)) + goto err; + + pr->mode = sb.st_mode; + if (S_ISBLK(sb.st_mode) || S_ISCHR(sb.st_mode)) + pr->devno = sb.st_rdev; + + if (size) + pr->size = size; + else { + if (S_ISBLK(sb.st_mode)) { + if (blkdev_get_size(fd, (unsigned long long *) &pr->size)) { + DBG(DEBUG_LOWPROBE, printf( + "failed to get device size\n")); + goto err; + } + } else if (S_ISCHR(sb.st_mode)) + pr->size = 1; /* UBI devices are char... */ + else if (S_ISREG(sb.st_mode)) + pr->size = sb.st_size; /* regular file */ + + if (pr->off > pr->size) + goto err; + + /* The probing area cannot be larger than whole device, pr->off + * is offset within the device */ + pr->size -= pr->off; + } + + if (pr->size <= 1440 * 1024 && !S_ISCHR(sb.st_mode)) + pr->flags |= BLKID_FL_TINY_DEV; + +#ifdef CDROM_GET_CAPABILITY + if (S_ISBLK(sb.st_mode) && + !blkid_probe_is_tiny(pr) && + blkid_probe_is_wholedisk(pr) && + ioctl(fd, CDROM_GET_CAPABILITY, NULL) >= 0) + pr->flags |= BLKID_FL_CDROM_DEV; +#endif + + DBG(DEBUG_LOWPROBE, printf("ready for low-probing, offset=%jd, size=%jd\n", + pr->off, pr->size)); + DBG(DEBUG_LOWPROBE, printf("whole-disk: %s, regfile: %s\n", + blkid_probe_is_wholedisk(pr) ?"YES" : "NO", + S_ISREG(pr->mode) ? "YES" : "NO")); + + return 0; +err: + DBG(DEBUG_LOWPROBE, + printf("failed to prepare a device for low-probing\n")); + return -1; + +} + +int blkid_probe_get_dimension(blkid_probe pr, + blkid_loff_t *off, blkid_loff_t *size) +{ + if (!pr) + return -1; + + *off = pr->off; + *size = pr->size; + return 0; +} + +int blkid_probe_set_dimension(blkid_probe pr, + blkid_loff_t off, blkid_loff_t size) +{ + if (!pr) + return -1; + + DBG(DEBUG_LOWPROBE, printf( + "changing probing area pr=%p: size=%llu, off=%llu " + "-to-> size=%llu, off=%llu\n", + pr, + (unsigned long long) pr->size, + (unsigned long long) pr->off, + (unsigned long long) size, + (unsigned long long) off)); + + pr->off = off; + pr->size = size; + pr->flags &= ~BLKID_FL_TINY_DEV; + + if (pr->size <= 1440 * 1024 && !S_ISCHR(pr->mode)) + pr->flags |= BLKID_FL_TINY_DEV; + + blkid_probe_reset_buffer(pr); + + return 0; +} + +int blkid_probe_get_idmag(blkid_probe pr, const struct blkid_idinfo *id, + blkid_loff_t *offset, const struct blkid_idmag **res) +{ + const struct blkid_idmag *mag = NULL; + blkid_loff_t off = 0; + + if (id) + mag = &id->magics[0]; + if (res) + *res = NULL; + + /* try to detect by magic string */ + while(mag && mag->magic) { + unsigned char *buf; + + off = (mag->kboff + (mag->sboff >> 10)) << 10; + buf = blkid_probe_get_buffer(pr, off, 1024); + + if (buf && !memcmp(mag->magic, + buf + (mag->sboff & 0x3ff), mag->len)) { + DBG(DEBUG_LOWPROBE, printf( + "\tmagic sboff=%u, kboff=%ld\n", + mag->sboff, mag->kboff)); + if (offset) + *offset = off + (mag->sboff & 0x3ff); + if (res) + *res = mag; + return 0; + } + mag++; + } + + if (id && id->magics[0].magic) + /* magic string(s) defined, but not found */ + return 1; + + return 0; +} + +static inline void blkid_probe_start(blkid_probe pr) +{ + if (pr) { + DBG(DEBUG_LOWPROBE, printf("%p: start probe\n", pr)); + pr->cur_chain = NULL; + pr->prob_flags = 0; + blkid_probe_set_wiper(pr, 0, 0); + } +} + +static inline void blkid_probe_end(blkid_probe pr) +{ + if (pr) { + DBG(DEBUG_LOWPROBE, printf("%p: end probe\n", pr)); + pr->cur_chain = NULL; + pr->prob_flags = 0; + blkid_probe_set_wiper(pr, 0, 0); + } +} + +/** + * blkid_do_probe: + * @pr: prober + * + * Calls probing functions in all enabled chains. The superblocks chain is + * enabled by default. The blkid_do_probe() stores result from only one + * probing function. It's necessary to call this routine in a loop to get + * results from all probing functions in all chains. The probing is reset + * by blkid_reset_probe() or by filter functions. + * + * This is string-based NAME=value interface only. + * + * <example> + * <title>basic case - use the first result only</title> + * <programlisting> + * + * if (blkid_do_probe(pr) == 0) { + * int nvals = blkid_probe_numof_values(pr); + * for (n = 0; n < nvals; n++) { + * if (blkid_probe_get_value(pr, n, &name, &data, &len) == 0) + * printf("%s = %s\n", name, data); + * } + * } + * </programlisting> + * </example> + * + * <example> + * <title>advanced case - probe for all signatures</title> + * <programlisting> + * + * while (blkid_do_probe(pr) == 0) { + * int nvals = blkid_probe_numof_values(pr); + * ... + * } + * </programlisting> + * </example> + * + * See also blkid_reset_probe(). + * + * Returns: 0 on success, 1 when probing is done and -1 in case of error. + */ +int blkid_do_probe(blkid_probe pr) +{ + int rc = 1; + + if (!pr) + return -1; + + do { + struct blkid_chain *chn = pr->cur_chain; + + if (!chn) { + blkid_probe_start(pr); + chn = pr->cur_chain = &pr->chains[0]; + } + /* we go to the next chain only when the previous probing + * result was nothing (rc == 1) and when the current chain is + * disabled or we are at end of the current chain (chain->idx + + * 1 == sizeof chain) or the current chain bailed out right at + * the start (chain->idx == -1) + */ + else if (rc == 1 && (chn->enabled == FALSE || + chn->idx + 1 == (int) chn->driver->nidinfos || + chn->idx == -1)) { + + size_t idx = chn->driver->id + 1; + + if (idx < BLKID_NCHAINS) + chn = pr->cur_chain = &pr->chains[idx]; + else { + blkid_probe_end(pr); + return 1; /* all chains already probed */ + } + } + + chn->binary = FALSE; /* for sure... */ + + DBG(DEBUG_LOWPROBE, printf("chain probe %s %s (idx=%d)\n", + chn->driver->name, + chn->enabled? "ENABLED" : "DISABLED", + chn->idx)); + + if (!chn->enabled) + continue; + + /* rc: -1 = error, 0 = success, 1 = no result */ + rc = chn->driver->probe(pr, chn); + + } while (rc == 1); + + return rc; +} + +/** + * blkid_do_wipe: + * @pr: prober + * @dryrun: if TRUE then don't touch the device. + * + * This function erases the current signature detected by @pr. The @pr has to + * be open in O_RDWR mode, BLKID_SUBLKS_MAGIC or/and BLKID_PARTS_MAGIC flags + * has to be enabled. + * + * After successful signature removing the @pr prober will be moved one step + * back and the next blkid_do_probe() call will again call previously called + * probing function. + * + * <example> + * <title>wipe all filesystems or raids from the device</title> + * <programlisting> + * fd = open(devname, O_RDWR|O_CLOEXEC); + * blkid_probe_set_device(pr, fd, 0, 0); + * + * blkid_probe_enable_superblocks(pr, 1); + * blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_MAGIC); + * + * while (blkid_do_probe(pr) == 0) + * blkid_do_wipe(pr, FALSE); + * </programlisting> + * </example> + * + * See also blkid_probe_step_back() if you cannot use this build-in wipe + * function, but you want to use libblkid probing as a source for wiping. + * + * Returns: 0 on success, and -1 in case of error. + */ +int blkid_do_wipe(blkid_probe pr, int dryrun) +{ + const char *off = NULL; + size_t len = 0; + loff_t offset, l; + char buf[BUFSIZ]; + int fd, rc = 0; + struct blkid_chain *chn; + + if (!pr) + return -1; + + chn = pr->cur_chain; + if (!chn) + return -1; + + switch (chn->driver->id) { + case BLKID_CHAIN_SUBLKS: + rc = blkid_probe_lookup_value(pr, "SBMAGIC_OFFSET", &off, NULL); + if (!rc) + rc = blkid_probe_lookup_value(pr, "SBMAGIC", NULL, &len); + break; + case BLKID_CHAIN_PARTS: + rc = blkid_probe_lookup_value(pr, "PTMAGIC_OFFSET", &off, NULL); + if (!rc) + rc = blkid_probe_lookup_value(pr, "PTMAGIC", NULL, &len); + break; + default: + return 0; + } + + if (rc || len == 0 || off == NULL) + return 0; + + offset = strtoll(off, NULL, 10); + fd = blkid_probe_get_fd(pr); + if (fd < 0) + return -1; + + if (len > sizeof(buf)) + len = sizeof(buf); + + DBG(DEBUG_LOWPROBE, printf( + "do_wipe [offset=0x%jx, len=%zd, chain=%s, idx=%d, dryrun=%s]\n", + offset, len, chn->driver->name, chn->idx, dryrun ? "yes" : "not")); + + l = lseek(fd, offset, SEEK_SET); + if (l == (off_t) -1) + return -1; + + memset(buf, 0, len); + + if (!dryrun && len) { + if (write_all(fd, buf, len)) + return -1; + fsync(fd); + return blkid_probe_step_back(pr); + } + + return 0; +} + +/** + * blkid_probe_step_back(): + * @pr: prober + * + * This function move pointer to the probing chain one step back -- it means + * that the previously used probing function will be called again in the next + * blkid_do_probe() call. + * + * This is necessary for example if you erase or modify on-disk superblock + * according to the current libblkid probing result. + * + * <example> + * <title>wipe all superblock, but use libblkid only for probing</title> + * <programlisting> + * pr = blkid_new_probe_from_filename(devname); + * + * blkid_probe_enable_superblocks(pr, 1); + * blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_MAGIC); + * + * while (blkid_do_probe(pr) == 0) { + * const char *ostr = NULL; + * size_t len = 0; + * + * // superblocks + * if (blkid_probe_lookup_value(pr, "SBMAGIC_OFFSET", &ostr, NULL) == 0) + * blkid_probe_lookup_value(pr, "SBMAGIC", NULL, &len); + * + * // partition tables + * if (len == 0 && blkid_probe_lookup_value(pr, "PTMAGIC_OFFSET", &ostr, NULL) == 0) + * blkid_probe_lookup_value(pr, "PTMAGIC", NULL, &len); + * + * if (!len || !str) + * continue; + * + * // convert ostr to the real offset by off = strtoll(ostr, NULL, 10); + * // use your stuff to errase @len bytes at the @off + * .... + * + * // retry the last probing to check for backup superblocks ..etc. + * blkid_probe_step_back(pr); + * } + * </programlisting> + * </example> + * + * Returns: 0 on success, and -1 in case of error. + */ +int blkid_probe_step_back(blkid_probe pr) +{ + struct blkid_chain *chn; + + if (!pr) + return -1; + + chn = pr->cur_chain; + if (!chn) + return -1; + + blkid_probe_reset_buffer(pr); + + if (chn->idx >= 0) { + chn->idx--; + DBG(DEBUG_LOWPROBE, + printf("step back: moving %s chain index to %d\n", + chn->driver->name, + chn->idx)); + } + + if (chn->idx == -1) { + /* blkid_do_probe() goes to the next chain if the index + * of the current chain is -1, so we have to set the + * chain pointer to the previous chain. + */ + size_t idx = chn->driver->id > 0 ? chn->driver->id - 1 : 0; + + DBG(DEBUG_LOWPROBE, printf("step back: moving to previous chain\n")); + + if (idx > 0) + pr->cur_chain = &pr->chains[idx]; + else if (idx == 0) + pr->cur_chain = NULL; + } + + return 0; +} + +/** + * blkid_do_safeprobe: + * @pr: prober + * + * This function gathers probing results from all enabled chains and checks + * for ambivalent results (e.g. more filesystems on the device). + * + * This is string-based NAME=value interface only. + * + * Note about suberblocks chain -- the function does not check for filesystems + * when a RAID signature is detected. The function also does not check for + * collision between RAIDs. The first detected RAID is returned. The function + * checks for collision between partition table and RAID signature -- it's + * recommended to enable partitions chain together with superblocks chain. + * + * Returns: 0 on success, 1 if nothing is detected, -2 if ambivalen result is + * detected and -1 on case of error. + */ +int blkid_do_safeprobe(blkid_probe pr) +{ + int i, count = 0, rc = 0; + + if (!pr) + return -1; + + blkid_probe_start(pr); + + pr->prob_flags |= BLKID_PROBE_FL_IGNORE_BACKUP; + + for (i = 0; i < BLKID_NCHAINS; i++) { + struct blkid_chain *chn; + + chn = pr->cur_chain = &pr->chains[i]; + chn->binary = FALSE; /* for sure... */ + + DBG(DEBUG_LOWPROBE, printf("chain safeprobe %s %s\n", + chn->driver->name, + chn->enabled? "ENABLED" : "DISABLED")); + + if (!chn->enabled) + continue; + + blkid_probe_chain_reset_position(chn); + + rc = chn->driver->safeprobe(pr, chn); + + blkid_probe_chain_reset_position(chn); + + /* rc: -2 ambivalent, -1 = error, 0 = success, 1 = no result */ + if (rc < 0) + goto done; /* error */ + if (rc == 0) + count++; /* success */ + } + +done: + blkid_probe_end(pr); + if (rc < 0) + return rc; + return count ? 0 : 1; +} + +/** + * blkid_do_fullprobe: + * @pr: prober + * + * This function gathers probing results from all enabled chains. Same as + * blkid_do_safeprobe() but does not check for collision between probing + * result. + * + * This is string-based NAME=value interface only. + * + * Returns: 0 on success, 1 if nothing is detected or -1 on case of error. + */ +int blkid_do_fullprobe(blkid_probe pr) +{ + int i, count = 0, rc = 0; + + if (!pr) + return -1; + + blkid_probe_start(pr); + + for (i = 0; i < BLKID_NCHAINS; i++) { + struct blkid_chain *chn; + + chn = pr->cur_chain = &pr->chains[i]; + chn->binary = FALSE; /* for sure... */ + + DBG(DEBUG_LOWPROBE, printf("chain fullprobe %s: %s\n", + chn->driver->name, + chn->enabled? "ENABLED" : "DISABLED")); + + if (!chn->enabled) + continue; + + blkid_probe_chain_reset_position(chn); + + rc = chn->driver->probe(pr, chn); + + blkid_probe_chain_reset_position(chn); + + /* rc: -1 = error, 0 = success, 1 = no result */ + if (rc < 0) + goto done; /* error */ + if (rc == 0) + count++; /* success */ + } + +done: + blkid_probe_end(pr); + if (rc < 0) + return rc; + return count ? 0 : 1; +} + +/* same sa blkid_probe_get_buffer() but works with 512-sectors */ +unsigned char *blkid_probe_get_sector(blkid_probe pr, unsigned int sector) +{ + return pr ? blkid_probe_get_buffer(pr, + ((blkid_loff_t) sector) << 9, 0x200) : NULL; +} + +struct blkid_prval *blkid_probe_assign_value( + blkid_probe pr, const char *name) +{ + struct blkid_prval *v; + + if (!name) + return NULL; + if (pr->nvals >= BLKID_NVALS) + return NULL; + + v = &pr->vals[pr->nvals]; + v->name = name; + v->chain = pr->cur_chain; + pr->nvals++; + + DBG(DEBUG_LOWPROBE, + printf("assigning %s [%s]\n", name, v->chain->driver->name)); + return v; +} + +int blkid_probe_reset_last_value(blkid_probe pr) +{ + struct blkid_prval *v; + + if (pr == NULL || pr->nvals == 0) + return -1; + + v = &pr->vals[pr->nvals - 1]; + + DBG(DEBUG_LOWPROBE, + printf("un-assigning %s [%s]\n", v->name, v->chain->driver->name)); + + memset(v, 0, sizeof(struct blkid_prval)); + pr->nvals--; + + return 0; + +} + +int blkid_probe_set_value(blkid_probe pr, const char *name, + unsigned char *data, size_t len) +{ + struct blkid_prval *v; + + if (len > BLKID_PROBVAL_BUFSIZ) + len = BLKID_PROBVAL_BUFSIZ; + + v = blkid_probe_assign_value(pr, name); + if (!v) + return -1; + + memcpy(v->data, data, len); + v->len = len; + return 0; +} + +int blkid_probe_vsprintf_value(blkid_probe pr, const char *name, + const char *fmt, va_list ap) +{ + struct blkid_prval *v; + ssize_t len; + + v = blkid_probe_assign_value(pr, name); + if (!v) + return -1; + + len = vsnprintf((char *) v->data, sizeof(v->data), fmt, ap); + + if (len <= 0 || (size_t) len >= sizeof(v->data)) { + blkid_probe_reset_last_value(pr); + return -1; + } + v->len = len + 1; + return 0; +} + +int blkid_probe_sprintf_value(blkid_probe pr, const char *name, + const char *fmt, ...) +{ + int rc; + va_list ap; + + va_start(ap, fmt); + rc = blkid_probe_vsprintf_value(pr, name, fmt, ap); + va_end(ap); + + return rc; +} + +int blkid_probe_set_magic(blkid_probe pr, blkid_loff_t offset, + size_t len, unsigned char *magic) +{ + int rc = 0; + struct blkid_chain *chn = blkid_probe_get_chain(pr); + + if (!chn || !magic || !len || chn->binary) + return 0; + + switch (chn->driver->id) { + case BLKID_CHAIN_SUBLKS: + if (!(chn->flags & BLKID_SUBLKS_MAGIC)) + return 0; + rc = blkid_probe_set_value(pr, "SBMAGIC", magic, len); + if (!rc) + rc = blkid_probe_sprintf_value(pr, + "SBMAGIC_OFFSET", "%llu", (unsigned long long)offset); + break; + case BLKID_CHAIN_PARTS: + if (!(chn->flags & BLKID_PARTS_MAGIC)) + return 0; + rc = blkid_probe_set_value(pr, "PTMAGIC", magic, len); + if (!rc) + rc = blkid_probe_sprintf_value(pr, + "PTMAGIC_OFFSET", "%llu", (unsigned long long)offset); + break; + default: + break; + } + + return rc; +} + +/** + * blkid_probe_get_devno: + * @pr: probe + * + * Returns: block device number, or 0 for regular files. + */ +dev_t blkid_probe_get_devno(blkid_probe pr) +{ + return pr->devno; +} + +/** + * blkid_probe_get_wholedisk_devno: + * @pr: probe + * + * Returns: device number of the wholedisk, or 0 for regular files. + */ +dev_t blkid_probe_get_wholedisk_devno(blkid_probe pr) +{ + if (!pr->disk_devno) { + dev_t devno, disk_devno = 0; + + devno = blkid_probe_get_devno(pr); + if (!devno) + return 0; + + if (blkid_devno_to_wholedisk(devno, NULL, 0, &disk_devno) == 0) + pr->disk_devno = disk_devno; + } + return pr->disk_devno; +} + +/** + * blkid_probe_is_wholedisk: + * @pr: probe + * + * Returns: 1 if the device is whole-disk or 0. + */ +int blkid_probe_is_wholedisk(blkid_probe pr) +{ + dev_t devno, disk_devno; + + devno = blkid_probe_get_devno(pr); + if (!devno) + return 0; + + disk_devno = blkid_probe_get_wholedisk_devno(pr); + if (!disk_devno) + return 0; + + return devno == disk_devno; +} + +blkid_probe blkid_probe_get_wholedisk_probe(blkid_probe pr) +{ + dev_t disk; + + if (blkid_probe_is_wholedisk(pr)) + return NULL; /* this is not partition */ + + if (pr->parent) + /* this is cloned blkid_probe, use parent's stuff */ + return blkid_probe_get_wholedisk_probe(pr->parent); + + disk = blkid_probe_get_wholedisk_devno(pr); + + if (pr->disk_probe && pr->disk_probe->devno != disk) { + /* we have disk prober, but for another disk... close it */ + blkid_free_probe(pr->disk_probe); + pr->disk_probe = NULL; + } + + if (!pr->disk_probe) { + /* Open a new disk prober */ + char *disk_path = blkid_devno_to_devname(disk); + + if (!disk_path) + return NULL; + + DBG(DEBUG_LOWPROBE, printf("allocate a wholedisk probe\n")); + + pr->disk_probe = blkid_new_probe_from_filename(disk_path); + + free(disk_path); + + if (!pr->disk_probe) + return NULL; /* ENOMEM? */ + } + + return pr->disk_probe; +} + +/** + * blkid_probe_get_size: + * @pr: probe + * + * This function returns size of probing area as defined by blkid_probe_set_device(). + * If the size of the probing area is unrestricted then this function returns + * the real size of device. See also blkid_get_dev_size(). + * + * Returns: size in bytes or -1 in case of error. + */ +blkid_loff_t blkid_probe_get_size(blkid_probe pr) +{ + return pr ? pr->size : -1; +} + +/** + * blkid_probe_get_offset: + * @pr: probe + * + * This function returns offset of probing area as defined by blkid_probe_set_device(). + * + * Returns: offset in bytes or -1 in case of error. + */ +blkid_loff_t blkid_probe_get_offset(blkid_probe pr) +{ + return pr ? pr->off : -1; +} + +/** + * blkid_probe_get_fd: + * @pr: probe + * + * Returns: file descriptor for assigned device/file or -1 in case of error. + */ +int blkid_probe_get_fd(blkid_probe pr) +{ + return pr ? pr->fd : -1; +} + +/** + * blkid_probe_get_sectorsize: + * @pr: probe or NULL (for NULL returns 512) + * + * Returns: block device logical sector size (BLKSSZGET ioctl, default 512). + */ +unsigned int blkid_probe_get_sectorsize(blkid_probe pr) +{ + if (!pr) + return DEFAULT_SECTOR_SIZE; /*... and good luck! */ + + if (pr->blkssz) + return pr->blkssz; + + if (S_ISBLK(pr->mode) && + blkdev_get_sector_size(pr->fd, (int *) &pr->blkssz) == 0) + return pr->blkssz; + + pr->blkssz = DEFAULT_SECTOR_SIZE; + return pr->blkssz; +} + +/** + * blkid_probe_get_sectors: + * @pr: probe + * + * Returns: 512-byte sector count or -1 in case of error. + */ +blkid_loff_t blkid_probe_get_sectors(blkid_probe pr) +{ + return pr ? pr->size >> 9 : -1; +} + +/** + * blkid_probe_numof_values: + * @pr: probe + * + * Returns: number of values in probing result or -1 in case of error. + */ +int blkid_probe_numof_values(blkid_probe pr) +{ + if (!pr) + return -1; + return pr->nvals; +} + +/** + * blkid_probe_get_value: + * @pr: probe + * @num: wanted value in range 0..N, where N is blkid_probe_numof_values() - 1 + * @name: pointer to return value name or NULL + * @data: pointer to return value data or NULL + * @len: pointer to return value length or NULL + * + * Note, the @len returns length of the @data, including the terminating + * '\0' character. + * + * Returns: 0 on success, or -1 in case of error. + */ +int blkid_probe_get_value(blkid_probe pr, int num, const char **name, + const char **data, size_t *len) +{ + struct blkid_prval *v = __blkid_probe_get_value(pr, num); + + if (!v) + return -1; + if (name) + *name = v->name; + if (data) + *data = (char *) v->data; + if (len) + *len = v->len; + + DBG(DEBUG_LOWPROBE, printf("returning %s value\n", v->name)); + return 0; +} + +/** + * blkid_probe_lookup_value: + * @pr: probe + * @name: name of value + * @data: pointer to return value data or NULL + * @len: pointer to return value length or NULL + * + * Note, the @len returns length of the @data, including the terminating + * '\0' character. + * + * Returns: 0 on success, or -1 in case of error. + */ +int blkid_probe_lookup_value(blkid_probe pr, const char *name, + const char **data, size_t *len) +{ + struct blkid_prval *v = __blkid_probe_lookup_value(pr, name); + + if (!v) + return -1; + if (data) + *data = (char *) v->data; + if (len) + *len = v->len; + return 0; +} + +/** + * blkid_probe_has_value: + * @pr: probe + * @name: name of value + * + * Returns: 1 if value exist in probing result, otherwise 0. + */ +int blkid_probe_has_value(blkid_probe pr, const char *name) +{ + if (blkid_probe_lookup_value(pr, name, NULL, NULL) == 0) + return 1; + return 0; +} + +struct blkid_prval *__blkid_probe_get_value(blkid_probe pr, int num) +{ + if (!pr || num < 0 || num >= pr->nvals) + return NULL; + + return &pr->vals[num]; +} + +struct blkid_prval *__blkid_probe_lookup_value(blkid_probe pr, const char *name) +{ + int i; + + if (!pr || !pr->nvals || !name) + return NULL; + + for (i = 0; i < pr->nvals; i++) { + struct blkid_prval *v = &pr->vals[i]; + + if (v->name && strcmp(name, v->name) == 0) { + DBG(DEBUG_LOWPROBE, printf("returning %s value\n", v->name)); + return v; + } + } + return NULL; +} + + +/* converts DCE UUID (uuid[16]) to human readable string + * - the @len should be always 37 */ +#ifdef HAVE_LIBUUID +void blkid_unparse_uuid(const unsigned char *uuid, char *str, + size_t len __attribute__((__unused__))) +{ + uuid_unparse(uuid, str); +} +#else +void blkid_unparse_uuid(const unsigned char *uuid, char *str, size_t len) +{ + snprintf(str, len, + "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", + uuid[0], uuid[1], uuid[2], uuid[3], + uuid[4], uuid[5], + uuid[6], uuid[7], + uuid[8], uuid[9], + uuid[10], uuid[11], uuid[12], uuid[13], uuid[14],uuid[15]); +} +#endif + + +/* Removes whitespace from the right-hand side of a string (trailing + * whitespace). + * + * Returns size of the new string (without \0). + */ +size_t blkid_rtrim_whitespace(unsigned char *str) +{ + size_t i = strlen((char *) str); + + while (i--) { + if (!isspace(str[i])) + break; + } + str[++i] = '\0'; + return i; +} + +/* Removes whitespace from the left-hand side of a string. + * + * Returns size of the new string (without \0). + */ +size_t blkid_ltrim_whitespace(unsigned char *str) +{ + size_t len; + unsigned char *p; + + for (p = str; p && isspace(*p); p++); + + len = strlen((char *) p); + + if (len && p > str) + memmove(str, p, len + 1); + + return len; +} +/* + * Some mkfs-like utils wipe some parts (usually begin) of the device. + * For example LVM (pvcreate) or mkswap(8). This information could be used + * for later resolution to conflicts between superblocks. + * + * For example we found valid LVM superblock, LVM wipes 8KiB at the begin of + * the device. If we found another signature (for example MBR) within the + * wiped area then the signature has been added later and LVM superblock + * should be ignore. + * + * Note that this heuristic is not 100% reliable, for example "pvcreate --zero + * n" allows to keep the begin of the device unmodified. It's probably better + * to use this heuristic for conflicts between superblocks and partition tables + * than for conflicts between filesystem superblocks -- existence of unwanted + * partition table is very unusual, because PT is pretty visible (parsed and + * interpreted by kernel). + * + * Note that we usually expect only one signature on the device, it means that + * we have to remember only one wiped area from previously successfully + * detected signature. + * + * blkid_probe_set_wiper() -- defines wiped area (e.g. LVM) + * blkid_probe_use_wiper() -- try to use area (e.g. MBR) + * + * Note that there is not relation between _wiper and blkid_to_wipe(). + * + */ +void blkid_probe_set_wiper(blkid_probe pr, blkid_loff_t off, blkid_loff_t size) +{ + struct blkid_chain *chn; + + if (!pr) + return; + + if (!size) { + DBG(DEBUG_LOWPROBE, printf("zeroize wiper\n")); + pr->wipe_size = pr->wipe_off = 0; + pr->wipe_chain = NULL; + return; + } + + chn = pr->cur_chain; + + if (!chn || !chn->driver || + chn->idx < 0 || (size_t) chn->idx >= chn->driver->nidinfos) + return; + + pr->wipe_size = size; + pr->wipe_off = off; + pr->wipe_chain = chn; + + DBG(DEBUG_LOWPROBE, + printf("wiper set to %s::%s off=%jd size=%jd\n", + chn->driver->name, + chn->driver->idinfos[chn->idx]->name, + pr->wipe_off, pr->wipe_size)); + return; +} + +/* + * Returns 1 if the <@off,@size> area was wiped + */ +int blkid_probe_is_wiped(blkid_probe pr, struct blkid_chain **chn, + blkid_loff_t off, blkid_loff_t size) +{ + if (!pr || !size) + return 0; + + if (pr->wipe_off <= off && off + size <= pr->wipe_off + pr->wipe_size) { + if (chn) + *chn = pr->wipe_chain; + return 1; + } + return 0; +} + +/* + * Try to use any area -- if the area has been previously wiped then the + * previous probing result should be ignored (reseted). + */ +void blkid_probe_use_wiper(blkid_probe pr, blkid_loff_t off, blkid_loff_t size) +{ + struct blkid_chain *chn = NULL; + + if (blkid_probe_is_wiped(pr, &chn, off, size) && chn) { + DBG(DEBUG_LOWPROBE, printf("previously wiped area modified " + " -- ignore previous results\n")); + blkid_probe_set_wiper(pr, 0, 0); + blkid_probe_chain_reset_vals(pr, chn); + } +} + +int blkid_probe_ignore_backup(blkid_probe pr) +{ + return pr && (pr->prob_flags & BLKID_PROBE_FL_IGNORE_BACKUP); +} |