tools:iio:iio_utils: implement digit calculation
authorHartmut Knaack <knaack.h@gmx.de>
Sun, 31 May 2015 12:40:00 +0000 (14:40 +0200)
committerJonathan Cameron <jic23@kernel.org>
Sun, 31 May 2015 18:18:55 +0000 (19:18 +0100)
Previously, the return value of sscanf() was treated as an indication of
the digits it would have read. Yet, sscanf() only returns the amount of
valid matches.
Therefore, introduce a function to calculate the decimal digits of the
read number and use this one to commence a colon search, as originally
intended.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
tools/iio/iio_utils.c

index c5b4136e648a6a2946d64486b5bb96436591f803..60e5ec4165b70d0fa3e310891393f6ffd2458eda 100644 (file)
@@ -431,6 +431,18 @@ error_ret:
        return ret;
 }
 
+int calc_digits(int num)
+{
+       int count = 0;
+
+       while (num != 0) {
+               num /= 10;
+               count++;
+       }
+
+       return count;
+}
+
 /**
  * find_type_by_name() - function to match top level types by name
  * @name: top level type instance name
@@ -441,7 +453,7 @@ error_ret:
 int find_type_by_name(const char *name, const char *type)
 {
        const struct dirent *ent;
-       int number, numstrlen;
+       int number, numstrlen, ret;
 
        FILE *nameFile;
        DIR *dp;
@@ -459,9 +471,19 @@ int find_type_by_name(const char *name, const char *type)
                        strcmp(ent->d_name, "..") != 0 &&
                        strlen(ent->d_name) > strlen(type) &&
                        strncmp(ent->d_name, type, strlen(type)) == 0) {
-                       numstrlen = sscanf(ent->d_name + strlen(type),
-                                          "%d",
-                                          &number);
+                       errno = 0;
+                       ret = sscanf(ent->d_name + strlen(type), "%d", &number);
+                       if (ret < 0) {
+                               ret = -errno;
+                               printf("failed to read element number\n");
+                               goto error_close_dir;
+                       } else if (ret != 1) {
+                               ret = -EIO;
+                               printf("failed to match element number\n");
+                               goto error_close_dir;
+                       }
+
+                       numstrlen = calc_digits(number);
                        /* verify the next character is not a colon */
                        if (strncmp(ent->d_name + strlen(type) + numstrlen,
                                        ":",
@@ -495,6 +517,11 @@ int find_type_by_name(const char *name, const char *type)
        }
        closedir(dp);
        return -ENODEV;
+
+error_close_dir:
+       if (closedir(dp) == -1)
+               perror("find_type_by_name(): Failed to close directory");
+       return ret;
 }
 
 int _write_sysfs_int(char *filename, char *basedir, int val, int verify)