select: fix 64-bit timeout truncation on pre-time64 kernels

[musl] / src / stdio / getdelim.c

diff --git a/src/stdio/getdelim.c b/src/stdio/getdelim.c
index 3077490..df11444 100644 (file)
--- a/src/stdio/getdelim.c
+++ b/src/stdio/getdelim.c
@@ -1,10 +1,9 @@
 #include "stdio_impl.h"
 #include <string.h>
+#include <stdlib.h>
 #include <inttypes.h>
 #include <errno.h>
 
-#define MIN(a,b) ((a)<(b) ? (a) : (b))
-
 ssize_t getdelim(char **restrict s, size_t *restrict n, int delim, FILE *restrict f)
 {
        char *tmp;
@@ -16,6 +15,7 @@ ssize_t getdelim(char **restrict s, size_t *restrict n, int delim, FILE *restric
        FLOCK(f);
 
        if (!n || !s) {
+               f->mode |= f->mode-1;
                f->flags |= F_ERR;
                FUNLOCK(f);
                errno = EINVAL;
@@ -25,23 +25,41 @@ ssize_t getdelim(char **restrict s, size_t *restrict n, int delim, FILE *restric
        if (!*s) *n=0;
 
        for (;;) {
-               z = memchr(f->rpos, delim, f->rend - f->rpos);
-               k = z ? z - f->rpos + 1 : f->rend - f->rpos;
-               if (i+k+1 >= *n) {
-                       if (k >= SIZE_MAX/2-i) goto oom;
-                       *n = i+k+2;
-                       if (*n < SIZE_MAX/4) *n *= 2;
-                       tmp = realloc(*s, *n);
+               if (f->rpos != f->rend) {
+                       z = memchr(f->rpos, delim, f->rend - f->rpos);
+                       k = z ? z - f->rpos + 1 : f->rend - f->rpos;
+               } else {
+                       z = 0;
+                       k = 0;
+               }
+               if (i+k >= *n) {
+                       size_t m = i+k+2;
+                       if (!z && m < SIZE_MAX/4) m += m/2;
+                       tmp = realloc(*s, m);
                        if (!tmp) {
-                               *n = i+k+2;
-                               tmp = realloc(*s, *n);
-                               if (!tmp) goto oom;
+                               m = i+k+2;
+                               tmp = realloc(*s, m);
+                               if (!tmp) {
+                                       /* Copy as much as fits and ensure no
+                                        * pushback remains in the FILE buf. */
+                                       k = *n-i;
+                                       memcpy(*s+i, f->rpos, k);
+                                       f->rpos += k;
+                                       f->mode |= f->mode-1;
+                                       f->flags |= F_ERR;
+                                       FUNLOCK(f);
+                                       errno = ENOMEM;
+                                       return -1;
+                               }
                        }
                        *s = tmp;
+                       *n = m;
+               }
+               if (k) {
+                       memcpy(*s+i, f->rpos, k);
+                       f->rpos += k;
+                       i += k;
                }
-               memcpy(*s+i, f->rpos, k);
-               f->rpos += k;
-               i += k;
                if (z) break;
                if ((c = getc_unlocked(f)) == EOF) {
                        if (!i || !feof(f)) {
@@ -50,18 +68,16 @@ ssize_t getdelim(char **restrict s, size_t *restrict n, int delim, FILE *restric
                        }
                        break;
                }
-               if (((*s)[i++] = c) == delim) break;
+               /* If the byte read by getc won't fit without growing the
+                * output buffer, push it back for next iteration. */
+               if (i+1 >= *n) *--f->rpos = c;
+               else if (((*s)[i++] = c) == delim) break;
        }
        (*s)[i] = 0;
 
        FUNLOCK(f);
 
        return i;
-oom:
-       f->flags |= F_ERR;
-       FUNLOCK(f);
-       errno = ENOMEM;
-       return -1;
 }
 
 weak_alias(getdelim, __getdelim);