diff options
| -rw-r--r-- | include/sysfs.h | 10 | ||||
| -rw-r--r-- | lib/sysfs.c | 136 |
2 files changed, 130 insertions, 16 deletions
diff --git a/include/sysfs.h b/include/sysfs.h index 5190ac482..a26e0a72e 100644 --- a/include/sysfs.h +++ b/include/sysfs.h @@ -27,9 +27,10 @@ struct sysfs_cxt { extern char *sysfs_devno_attribute_path(dev_t devno, char *buf, - size_t buflen, const char *attr); + size_t bufsiz, const char *attr); extern int sysfs_devno_has_attribute(dev_t devno, const char *attr); -extern char *sysfs_devno_path(dev_t devno, char *buf, size_t buflen); +extern char *sysfs_devno_path(dev_t devno, char *buf, size_t bufsiz); +extern char *sysfs_devno_to_devpath(dev_t devno, char *buf, size_t bufsiz); extern dev_t sysfs_devname_to_devno(const char *name, const char *parent); extern int sysfs_init(struct sysfs_cxt *cxt, dev_t devno, @@ -39,6 +40,8 @@ extern void sysfs_deinit(struct sysfs_cxt *cxt); extern DIR *sysfs_opendir(struct sysfs_cxt *cxt, const char *attr); extern int sysfs_stat(struct sysfs_cxt *cxt, const char *attr, struct stat *st); +extern ssize_t sysfs_readlink(struct sysfs_cxt *cxt, const char *attr, + char *buf, size_t bufsiz); extern int sysfs_has_attribute(struct sysfs_cxt *cxt, const char *attr); extern int sysfs_scanf(struct sysfs_cxt *cxt, const char *attr, @@ -49,10 +52,13 @@ extern int sysfs_read_s64(struct sysfs_cxt *cxt, const char *attr, int64_t *res) extern int sysfs_read_u64(struct sysfs_cxt *cxt, const char *attr, uint64_t *res); extern int sysfs_read_int(struct sysfs_cxt *cxt, const char *attr, int *res); +extern char *sysfs_get_devname(struct sysfs_cxt *cxt, char *buf, size_t bufsiz); + extern char *sysfs_strdup(struct sysfs_cxt *cxt, const char *attr); extern int sysfs_count_dirents(struct sysfs_cxt *cxt, const char *attr); extern int sysfs_count_partitions(struct sysfs_cxt *cxt, const char *devname); +extern char *sysfs_get_slave(struct sysfs_cxt *cxt); extern int sysfs_is_partition_dirent(DIR *dir, struct dirent *d, const char *parent_name); diff --git a/lib/sysfs.c b/lib/sysfs.c index 3b8052390..1f64c641d 100644 --- a/lib/sysfs.c +++ b/lib/sysfs.c @@ -8,18 +8,18 @@ #include "sysfs.h" char *sysfs_devno_attribute_path(dev_t devno, char *buf, - size_t buflen, const char *attr) + size_t bufsiz, const char *attr) { int len; if (attr) - len = snprintf(buf, buflen, _PATH_SYS_DEVBLOCK "/%d:%d/%s", + len = snprintf(buf, bufsiz, _PATH_SYS_DEVBLOCK "/%d:%d/%s", major(devno), minor(devno), attr); else - len = snprintf(buf, buflen, _PATH_SYS_DEVBLOCK "/%d:%d", + len = snprintf(buf, bufsiz, _PATH_SYS_DEVBLOCK "/%d:%d", major(devno), minor(devno)); - return (len < 0 || len + 1 > buflen) ? NULL : buf; + return (len < 0 || len + 1 > bufsiz) ? NULL : buf; } int sysfs_devno_has_attribute(dev_t devno, const char *attr) @@ -34,9 +34,9 @@ int sysfs_devno_has_attribute(dev_t devno, const char *attr) return 0; } -char *sysfs_devno_path(dev_t devno, char *buf, size_t buflen) +char *sysfs_devno_path(dev_t devno, char *buf, size_t bufsiz) { - return sysfs_devno_attribute_path(devno, buf, buflen, NULL); + return sysfs_devno_attribute_path(devno, buf, bufsiz, NULL); } dev_t sysfs_devname_to_devno(const char *name, const char *parent) @@ -95,22 +95,61 @@ dev_t sysfs_devname_to_devno(const char *name, const char *parent) return dev; } +/* + * Returns devname (e.g. "/dev/sda1") for the given devno. + * + * Note that the @buf has to be large enough to store /sys/dev/block/<maj:min> + * symlinks. + * + * Please, use more robust blkid_devno_to_devname() in your applications. + */ +char *sysfs_devno_to_devpath(dev_t devno, char *buf, size_t bufsiz) +{ + struct sysfs_cxt cxt; + char *name; + size_t sz; + struct stat st; + + if (sysfs_init(&cxt, devno, NULL)) + return NULL; + + name = sysfs_get_devname(&cxt, buf, bufsiz); + sysfs_deinit(&cxt); + + if (!name) + return NULL; + + sz = strlen(name); + + if (sz + sizeof("/dev/") > bufsiz) + return NULL; + + /* create the final "/dev/<name>" string */ + memmove(buf + 5, name, sz + 1); + memcpy(buf, "/dev/", 5); + + if (!stat(buf, &st) && S_ISBLK(st.st_mode) && st.st_rdev == devno) + return buf; + + return NULL; +} + int sysfs_init(struct sysfs_cxt *cxt, dev_t devno, struct sysfs_cxt *parent) { char path[PATH_MAX]; int fd, rc = 0; + memset(cxt, 0, sizeof(*cxt)); + if (!sysfs_devno_path(devno, path, sizeof(path))) goto err; fd = open(path, O_RDONLY); if (fd < 0) goto err; -#ifndef HAVE_FSTATAT cxt->dir_path = strdup(path); if (!cxt->dir_path) goto err; -#endif cxt->devno = devno; cxt->dir_fd = fd; cxt->parent = parent; @@ -131,9 +170,7 @@ void sysfs_deinit(struct sysfs_cxt *cxt) cxt->devno = 0; cxt->dir_fd = -1; cxt->parent = NULL; -#ifndef HAVE_FSTATAT free(cxt->dir_path); -#endif } int sysfs_stat(struct sysfs_cxt *cxt, const char *attr, struct stat *st) @@ -174,6 +211,16 @@ static int sysfs_open(struct sysfs_cxt *cxt, const char *attr) return fd; } +ssize_t sysfs_readlink(struct sysfs_cxt *cxt, const char *attr, + char *buf, size_t bufsiz) +{ + if (attr) + return readlink_at(cxt->dir_fd, cxt->dir_path, attr, buf, bufsiz); + + /* read /sys/dev/block/<maj:min> link */ + return readlink(cxt->dir_path, buf, bufsiz); +} + DIR *sysfs_opendir(struct sysfs_cxt *cxt, const char *attr) { DIR *dir; @@ -181,13 +228,12 @@ DIR *sysfs_opendir(struct sysfs_cxt *cxt, const char *attr) if (attr) fd = sysfs_open(cxt, attr); - else { + else /* request to open root of device in sysfs (/sys/block/<dev>) * -- we cannot use cxt->sysfs_fd directly, because closedir() * will close this our persistent file descriptor. */ fd = dup(cxt->dir_fd); - } if (fd < 0) return NULL; @@ -259,6 +305,7 @@ int sysfs_scanf(struct sysfs_cxt *cxt, const char *attr, const char *fmt, ...) return rc; } + int sysfs_read_s64(struct sysfs_cxt *cxt, const char *attr, int64_t *res) { int64_t x = 0; @@ -334,6 +381,57 @@ int sysfs_count_partitions(struct sysfs_cxt *cxt, const char *devname) return r; } +/* + * Returns slave name if there is only one slave, otherwise returns NULL. + * The result should be deallocated by free(). + */ +char *sysfs_get_slave(struct sysfs_cxt *cxt) +{ + DIR *dir; + struct dirent *d; + char *name = NULL; + + if (!(dir = sysfs_opendir(cxt, "slaves"))) + return NULL; + + while ((d = xreaddir(dir))) { + if (name) + goto err; /* more slaves */ + + name = strdup(d->d_name); + } + + closedir(dir); + return name; +err: + free(name); + return NULL; +} + +/* + * Note that the @buf has to be large enough to store /sys/dev/block/<maj:min> + * symlinks. + */ +char *sysfs_get_devname(struct sysfs_cxt *cxt, char *buf, size_t bufsiz) +{ + char *name = NULL; + ssize_t sz; + + sz = sysfs_readlink(cxt, NULL, buf, bufsiz - 1); + if (sz < 0) + return NULL; + + buf[sz] = '\0'; + name = strrchr(buf, '/'); + if (!name) + return NULL; + + name++; + sz = strlen(name); + + memmove(buf, name, sz + 1); + return buf; +} #ifdef TEST_PROGRAM #include <errno.h> @@ -348,6 +446,7 @@ int main(int argc, char *argv[]) char path[PATH_MAX]; int i; uint64_t u64; + ssize_t len; if (argc != 2) errx(EXIT_FAILURE, "usage: %s <devname>", argv[0]); @@ -361,23 +460,32 @@ int main(int argc, char *argv[]) printf("NAME: %s\n", devname); printf("DEVNO: %u\n", (unsigned int) devno); printf("DEVNOPATH: %s\n", sysfs_devno_path(devno, path, sizeof(path))); + printf("DEVPATH: %s\n", sysfs_devno_to_devpath(devno, path, sizeof(path))); printf("PARTITION: %s\n", sysfs_devno_has_attribute(devno, "partition") ? "YES" : "NOT"); sysfs_init(&cxt, devno, NULL); + len = sysfs_readlink(&cxt, NULL, path, sizeof(path) - 1); + if (len > 0) { + path[len] = '\0'; + printf("DEVNOLINK: %s\n", path); + } + printf("SLAVES: %d\n", sysfs_count_dirents(&cxt, "slaves")); if (sysfs_read_u64(&cxt, "size", &u64)) - printf("read SIZE failed"); + printf("read SIZE failed\n"); else printf("SIZE: %jd\n", u64); if (sysfs_read_int(&cxt, "queue/hw_sector_size", &i)) - printf("read SECTOR failed"); + printf("read SECTOR failed\n"); else printf("SECTOR: %d\n", i); + printf("DEVNAME: %s\n", sysfs_get_devname(&cxt, path, sizeof(path))); + return EXIT_SUCCESS; } #endif |