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author | David Oberhollenzer <david.oberhollenzer@sigma-star.at> | 2018-09-19 10:57:34 +0200 |
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committer | David Oberhollenzer <david.oberhollenzer@sigma-star.at> | 2018-09-20 11:27:01 +0200 |
commit | 38a6e3e29d90e11c3d5147e609d7b8e021b2cabf (patch) | |
tree | 8ba5cf8d7df5bde31ff2b4f1287b9f3b8feffc78 | |
parent | a63a209d8ee8f21722a3b07d01d904bca5dbbc31 (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.h | 7 |
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; } |