From 90e9fcda3bb3a215f027fc66c1182a18e0746972 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Wed, 18 May 2011 11:57:17 +0200 Subject: lib: [sysfs.c] make sysfs_read_* function more robust The functions does not modify result if the requested sysfs attribute does not exist. Signed-off-by: Karel Zak --- lib/sysfs.c | 50 +++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 39 insertions(+), 11 deletions(-) (limited to 'lib/sysfs.c') diff --git a/lib/sysfs.c b/lib/sysfs.c index bc380c030..3b8052390 100644 --- a/lib/sysfs.c +++ b/lib/sysfs.c @@ -259,22 +259,40 @@ int sysfs_scanf(struct sysfs_cxt *cxt, const char *attr, const char *fmt, ...) return rc; } -int64_t sysfs_read_s64(struct sysfs_cxt *cxt, const char *attr) +int sysfs_read_s64(struct sysfs_cxt *cxt, const char *attr, int64_t *res) { - uint64_t x; - return sysfs_scanf(cxt, attr, "%"SCNd64, &x) == 1 ? x : 0; + int64_t x = 0; + + if (sysfs_scanf(cxt, attr, "%"SCNd64, &x) == 1) { + if (res) + *res = x; + return 0; + } + return -1; } -uint64_t sysfs_read_u64(struct sysfs_cxt *cxt, const char *attr) +int sysfs_read_u64(struct sysfs_cxt *cxt, const char *attr, uint64_t *res) { - uint64_t x; - return sysfs_scanf(cxt, attr, "%"SCNu64, &x) == 1 ? x : 0; + uint64_t x = 0; + + if (sysfs_scanf(cxt, attr, "%"SCNu64, &x) == 1) { + if (res) + *res = x; + return 0; + } + return -1; } -int sysfs_read_int(struct sysfs_cxt *cxt, const char *attr) +int sysfs_read_int(struct sysfs_cxt *cxt, const char *attr, int *res) { - int x; - return sysfs_scanf(cxt, attr, "%d", &x) == 1 ? x : 0; + int x = 0; + + if (sysfs_scanf(cxt, attr, "%d", &x) == 1) { + if (res) + *res = x; + return 0; + } + return -1; } char *sysfs_strdup(struct sysfs_cxt *cxt, const char *attr) @@ -328,6 +346,8 @@ int main(int argc, char *argv[]) char *devname; dev_t devno; char path[PATH_MAX]; + int i; + uint64_t u64; if (argc != 2) errx(EXIT_FAILURE, "usage: %s ", argv[0]); @@ -347,8 +367,16 @@ int main(int argc, char *argv[]) sysfs_init(&cxt, devno, NULL); printf("SLAVES: %d\n", sysfs_count_dirents(&cxt, "slaves")); - printf("SIZE: %jd\n", sysfs_read_u64(&cxt, "size")); - printf("SECTOR: %d\n", sysfs_read_int(&cxt, "queue/hw_sector_size")); + + if (sysfs_read_u64(&cxt, "size", &u64)) + printf("read SIZE failed"); + else + printf("SIZE: %jd\n", u64); + + if (sysfs_read_int(&cxt, "queue/hw_sector_size", &i)) + printf("read SECTOR failed"); + else + printf("SECTOR: %d\n", i); return EXIT_SUCCESS; } -- cgit v1.2.3-55-g7522