Qu Wenruo
2014-Jun-13 02:55 UTC
[PATCH v3] btrfs-progs: Improve the parse_size() error message.
When using parse_size(), even non-numeric value is passed, it will only give error message "ERROR: size value is empty", which is quite confusing for end users. This patch will introduce more meaningful error message for the following new cases 1) Invalid size string (non-numeric string) 2) Minus size value (like "-1K") Also this patch will take full use of endptr returned by strtoll() to reduce unneeded loop. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> --- changlog: v2: Remove uneeded return value Avoid abuse of goto v3: Don't reparse size twice Better u64 overflow check --- utils.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 50 insertions(+), 16 deletions(-) diff --git a/utils.c b/utils.c index 392c5cf..eab3a1b 100644 --- a/utils.c +++ b/utils.c @@ -1610,20 +1610,53 @@ scan_again: return 0; } -u64 parse_size(char *s) +/* A not-so-good version fls64. No fascinating optimization since + * no one except parse_size use it */ +static int fls64(u64 x) { int i; + + for (i = 0; i <64; i++) + if (x << i & (1UL << 63)) + return 64 - i; + return 64 - i; +} + +u64 parse_size(char *s) +{ char c; + char *endptr; u64 mult = 1; + u64 ret; - for (i = 0; s && s[i] && isdigit(s[i]); i++) ; - if (!i) { - fprintf(stderr, "ERROR: size value is empty\n"); - exit(50); + if (!s) { + fprintf(stderr, "ERROR: Size value is empty\n"); + exit(1); } - - if (s[i]) { - c = tolower(s[i]); + if (s[0] == '-') { + fprintf(stderr, + "ERROR: Size value '%s' is less equal than 0\n", s); + exit(1); + } + ret = strtoull(s, &endptr, 10); + if (endptr == s) { + fprintf(stderr, "ERROR: Size value '%s' is invalid\n", s); + exit(1); + } + if (endptr[0] && endptr[1]) { + fprintf(stderr, "ERROR: Illegal suffix contains character '%c' in wrong position\n", + endptr[1]); + exit(1); + } + /* strtoll returns LLONG_MAX when overflow, if this happens, + * need to call strtoull to get the real size */ + if (errno == ERANGE && ret == ULLONG_MAX) { + fprintf(stderr, + "ERROR: Size value '%s' is too large for u64\n", s); + exit(1); + } + if (endptr[0]) { + c = tolower(endptr[0]); switch (c) { case 'e': mult *= 1024; @@ -1646,18 +1679,19 @@ u64 parse_size(char *s) case 'b': break; default: - fprintf(stderr, "ERROR: Unknown size descriptor " - "'%c'\n", c); + fprintf(stderr, "ERROR: Unknown size descriptor '%c'\n", + c); exit(1); } } - if (s[i] && s[i+1]) { - fprintf(stderr, "ERROR: Illegal suffix contains " - "character '%c' in wrong position\n", - s[i+1]); - exit(51); + /* Check whether ret * mult overflow */ + if (fls64(ret) + fls64(mult) - 1 > 64) { + fprintf(stderr, + "ERROR: Size value '%s' is too large for u64\n", s); + exit(1); } - return strtoull(s, NULL, 10) * mult; + ret *= mult; + return ret; } int open_file_or_dir3(const char *fname, DIR **dirstream, int open_flags) -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html