[nginx] Mp4: introduced custom version of ngx_atofp().
Maxim Dounin
mdounin at mdounin.ru
Thu Oct 27 15:05:38 UTC 2016
details: http://hg.nginx.org/nginx/rev/b123eae3fd4e
branches:
changeset: 6782:b123eae3fd4e
user: Maxim Dounin <mdounin at mdounin.ru>
date: Thu Oct 27 17:57:16 2016 +0300
description:
Mp4: introduced custom version of ngx_atofp().
This allows to correctly parse "start" and "end" arguments without
null-termination (ticket #475), and also fixes rounding errors observed
with strtod() when using i387 instructions.
diffstat:
src/http/modules/ngx_http_mp4_module.c | 74 +++++++++++++++++++++++++++------
1 files changed, 60 insertions(+), 14 deletions(-)
diffs (104 lines):
diff --git a/src/http/modules/ngx_http_mp4_module.c b/src/http/modules/ngx_http_mp4_module.c
--- a/src/http/modules/ngx_http_mp4_module.c
+++ b/src/http/modules/ngx_http_mp4_module.c
@@ -216,6 +216,7 @@ typedef struct {
static ngx_int_t ngx_http_mp4_handler(ngx_http_request_t *r);
+static ngx_int_t ngx_http_mp4_atofp(u_char *line, size_t n, size_t point);
static ngx_int_t ngx_http_mp4_process(ngx_http_mp4_file_t *mp4);
static ngx_int_t ngx_http_mp4_read_atom(ngx_http_mp4_file_t *mp4,
@@ -537,26 +538,15 @@ ngx_http_mp4_handler(ngx_http_request_t
/*
* A Flash player may send start value with a lot of digits
- * after dot so strtod() is used instead of atofp(). NaNs and
- * infinities become negative numbers after (int) conversion.
+ * after dot so a custom function is used instead of ngx_atofp().
*/
- ngx_set_errno(0);
- start = (int) (strtod((char *) value.data, NULL) * 1000);
-
- if (ngx_errno != 0) {
- start = -1;
- }
+ start = ngx_http_mp4_atofp(value.data, value.len, 3);
}
if (ngx_http_arg(r, (u_char *) "end", 3, &value) == NGX_OK) {
- ngx_set_errno(0);
- end = (int) (strtod((char *) value.data, NULL) * 1000);
-
- if (ngx_errno != 0) {
- end = -1;
- }
+ end = ngx_http_mp4_atofp(value.data, value.len, 3);
if (end > 0) {
if (start < 0) {
@@ -687,6 +677,62 @@ ngx_http_mp4_handler(ngx_http_request_t
static ngx_int_t
+ngx_http_mp4_atofp(u_char *line, size_t n, size_t point)
+{
+ ngx_int_t value, cutoff, cutlim;
+ ngx_uint_t dot;
+
+ /* same as ngx_atofp(), but allows additional digits */
+
+ if (n == 0) {
+ return NGX_ERROR;
+ }
+
+ cutoff = NGX_MAX_INT_T_VALUE / 10;
+ cutlim = NGX_MAX_INT_T_VALUE % 10;
+
+ dot = 0;
+
+ for (value = 0; n--; line++) {
+
+ if (*line == '.') {
+ if (dot) {
+ return NGX_ERROR;
+ }
+
+ dot = 1;
+ continue;
+ }
+
+ if (*line < '0' || *line > '9') {
+ return NGX_ERROR;
+ }
+
+ if (point == 0) {
+ continue;
+ }
+
+ if (value >= cutoff && (value > cutoff || *line - '0' > cutlim)) {
+ return NGX_ERROR;
+ }
+
+ value = value * 10 + (*line - '0');
+ point -= dot;
+ }
+
+ while (point--) {
+ if (value > cutoff) {
+ return NGX_ERROR;
+ }
+
+ value = value * 10;
+ }
+
+ return value;
+}
+
+
+static ngx_int_t
ngx_http_mp4_process(ngx_http_mp4_file_t *mp4)
{
off_t start_offset, end_offset, adjustment;
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