summaryrefslogtreecommitdiff
path: root/src
diff options
context:
space:
mode:
authorDavid Herrmann <dh.herrmann@gmail.com>2014-12-12 09:43:54 +0100
committerDavid Herrmann <dh.herrmann@gmail.com>2014-12-12 09:43:54 +0100
commitbff686e2a981ccd0888cdf1981977d24320f1770 (patch)
tree985439518c0dd5c3b3b7f9361d604e743c1d41ec /src
parent0b9315719154fa7ea1a075e1b3785713f5acc3a1 (diff)
hwdb: fix dangling 'else' ambuguity
Imagine the following use of hwdb: if (condition_A) SD_HWDB_FOREACH_PROPERTY(hwdb, modalias, key, value) operation_A(key, value); else log_error("..."); This should work just fine, but but definitely does not what you would expect. Due to how SD_HWDB_FOREACH_PROPERTY is defined, the dangling 'else' is linked to the hidden 'if' statement in the macro instead of the outer 'if (condition_A)'. This is unexpected and really annoying to debug. Fix this by never leaving un-finished if-statements in SD_HWDB_FOREACH_PROPERTY(). We simply inverse the if() statement and explicitly add an 'else'-branch. This way, the statement is closed and all ambuguities are resolved.
Diffstat (limited to 'src')
-rw-r--r--src/systemd/sd-hwdb.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/src/systemd/sd-hwdb.h b/src/systemd/sd-hwdb.h
index f41555df7e..3c44b981d6 100644
--- a/src/systemd/sd-hwdb.h
+++ b/src/systemd/sd-hwdb.h
@@ -39,8 +39,9 @@ int sd_hwdb_get(sd_hwdb *hwdb, const char *modalias, const char *key, const char
int sd_hwdb_seek(sd_hwdb *hwdb, const char *modalias);
int sd_hwdb_enumerate(sd_hwdb *hwdb, const char **key, const char **value);
+/* the inverse condition avoids ambiguity of danling 'else' after the macro */
#define SD_HWDB_FOREACH_PROPERTY(hwdb, modalias, key, value) \
- if (sd_hwdb_seek(hwdb, modalias) >= 0) \
- while (sd_hwdb_enumerate(hwdb, &(key), &(value)) > 0)
+ if (sd_hwdb_seek(hwdb, modalias) < 0) { } \
+ else while (sd_hwdb_enumerate(hwdb, &(key), &(value)) > 0)
#endif