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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2018-09-19 10:57:34 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2018-09-20 11:27:01 +0200
commit38a6e3e29d90e11c3d5147e609d7b8e021b2cabf (patch)
tree8ba5cf8d7df5bde31ff2b4f1287b9f3b8feffc78
parenta63a209d8ee8f21722a3b07d01d904bca5dbbc31 (diff)
mtd-utils: common.h: fix prompt function
The prompt() function is intended to query a yes/no reply from a command line user by reading in an entire line of text using getline() and checking the first character. If the line is empty, a default value is returned. First of all, this patch replaces the usage of getline() with fgets() to avoid compilation problems on some smaller C libraries, like klibc, that do not have a getline() implementation. Since we now have a static line length, this may break some build setups that input lengthy giberish instead of 'y' or 'n'. Second, this patch fixes a more severe bug in prompt(), replacing a 'while' keyword with the 'if' that was most likely intended. In the old version, if getline() reported an error, it would print an error message inside a while loop, immediately followed by a break and then march on and process the erroneous input instead of using the default value as printed to stdout. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
-rw-r--r--include/common.h7
1 files changed, 2 insertions, 5 deletions
diff --git a/include/common.h b/include/common.h
index 2ce5d22..ece2287 100644
--- a/include/common.h
+++ b/include/common.h
@@ -141,15 +141,14 @@ extern "C" {
*/
static inline bool prompt(const char *msg, bool def)
{
- char *line = NULL;
- size_t len;
bool ret = def;
+ char line[64];
do {
normsg_cont("%s (%c/%c) ", msg, def ? 'Y' : 'y', def ? 'n' : 'N');
fflush(stdout);
- while (getline(&line, &len, stdin) == -1) {
+ if (fgets(line, sizeof(line), stdin) == NULL) {
printf("failed to read prompt; assuming '%s'\n",
def ? "yes" : "no");
break;
@@ -169,8 +168,6 @@ static inline bool prompt(const char *msg, bool def)
break;
} while (1);
- free(line);
-
return ret;
}