@@ -1,3 +1,11 @@
+2016-04-27 Adhemerval Zanella <adhemerval.zanella@linaro.org>
+
+ [BZ #20012]
+ * libio/fmemopen.c (fmemopen_read): Use buffer maximum position, not
+ length to calculate the buffer to read.
+ (fmemopen_write): Set the buffer position based on bytes written.
+ (fmemopen_seek): Return EINVAL for invalid whence modes.
+
2016-04-27 Florian Weimer <fweimer@redhat.com>
[BZ #19831]
@@ -50,16 +50,14 @@ fmemopen_read (void *cookie, char *b, size_t s)
if (c->pos + s > c->maxpos)
{
- if ((size_t) c->pos == c->maxpos)
- return 0;
- s = c->size - c->pos;
+ s = c->maxpos - c->pos;
+ if ((size_t) c->pos > c->maxpos)
+ s = 0;
}
memcpy (b, &(c->buffer[c->pos]), s);
c->pos += s;
- if ((size_t) c->pos > c->maxpos)
- c->maxpos = c->pos;
return s;
}
@@ -70,28 +68,29 @@ fmemopen_write (void *cookie, const char *b, size_t s)
{
fmemopen_cookie_t *c = (fmemopen_cookie_t *) cookie;;
_IO_off64_t pos = c->append ? c->maxpos : c->pos;
- int addnullc;
-
- addnullc = (s == 0 || b[s - 1] != '\0');
+ int addnullc = (s == 0 || b[s - 1] != '\0');
- if (pos + s + addnullc > c->size)
+ if (pos + s > c->size)
{
if ((size_t) (c->pos + addnullc) >= c->size)
{
__set_errno (ENOSPC);
return 0;
}
- s = c->size - pos - addnullc;
+ s = c->size - pos;
}
memcpy (&(c->buffer[pos]), b, s);
- c->pos += s;
+ c->pos = pos + s;
if ((size_t) c->pos > c->maxpos)
{
c->maxpos = c->pos;
- if (addnullc)
+ if (c->maxpos < c->size && addnullc)
c->buffer[c->maxpos] = '\0';
+ /* A null byte is written in a stream open for update iff it fits. */
+ else if (c->append == 0 && addnullc != 0)
+ c->buffer[c->size-1] = '\0';
}
return s;
@@ -123,7 +122,10 @@ fmemopen_seek (void *cookie, _IO_off64_t *p, int w)
}
if (np < 0 || (size_t) np > c->size)
- return -1;
+ {
+ __set_errno (EINVAL);
+ return -1;
+ }
*p = c->pos = np;
@@ -25,8 +25,13 @@ static void
print_buffer (const char *s, size_t n)
{
size_t i;
+ printf ("{");
for (i=0; i<n; ++i)
- printf ("0x%02X (%c), ", s[i], s[i]);
+ {
+ printf ("0x%02X (%c)", s[i], s[i]);
+ if (i != n)
+ printf (", ");
+ }
}
/* This test check append mode initial position (a/a+) based on POSIX defition
@@ -186,6 +191,112 @@ do_test_read_seek_negative (void)
}
static int
+do_test_write_append_2 (const char *str)
+{
+ char buf[10];
+ size_t strn = strlen (str);
+ strcpy (buf, str);
+
+ FILE *fp = fmemopen (buf, sizeof (buf), "a+");
+ size_t r = ftell (fp);
+ size_t e = strlen (buf);
+ if (r != e)
+ {
+ printf ("%s: ftell returned %zu, expected %zu\n", __FUNCTION__, r, e);
+ return 1;
+ }
+
+ if (fseek (fp, 0, SEEK_SET) == -1)
+ {
+ printf ("%s: fseek returned -1\n", __FUNCTION__);
+ return 1;
+ }
+
+ int gr;
+ for (int i=0; i<strn; ++i)
+ {
+ if ((gr = getc (fp)) != str[i])
+ {
+ printf ("%s: getc failed returned %d, expected %d\n", __FUNCTION__,
+ gr, str[i]);
+ return 1;
+ }
+ }
+ if ((gr = getc (fp)) != EOF)
+ {
+ printf ("%s: getc failed returned %d, expected EOF\n", __FUNCTION__,
+ gr);
+ return 1;
+ }
+
+ if (fseek (fp, e+1, SEEK_SET) == -1)
+ {
+ printf ("%s: fseek returned -1\n", __FUNCTION__);
+ return 1;
+ }
+
+ if ((r = ftell (fp)) != e+1)
+ {
+ printf ("%s: ftell returned %zu, expected %zu\n", __FUNCTION__, r, e+1);
+ return 1;
+ }
+
+ if ((gr = getc (fp)) != EOF)
+ {
+ printf ("%s: getc failed returned %i\n", __FUNCTION__, gr);
+ return 1;
+ }
+
+ /* Check if internal position is not changed with a getc returning EOF. */
+ if ((r = ftell (fp)) != e+1)
+ {
+ printf ("%s: ftell returned %zu, expected %zu\n", __FUNCTION__, r, e+1);
+ return 1;
+ }
+
+ if (fseek (fp, 0, SEEK_CUR) == -1)
+ {
+ printf ("%s: fseek returned -1\n", __FUNCTION__);
+ return 1;
+ }
+
+ /* This should be overwritten by fprintf + fflush. */
+ buf[e+2] = 'X';
+
+ if ((r = fprintf (fp, "%d", 101)) != 3)
+ {
+ printf ("%s: fprintf returned %zu, expected %d\n", __FUNCTION__, r, 3);
+ return 1;
+ }
+
+ fflush (fp);
+
+ /* Check if internal position is changed by 3 (strlen of '101'). */
+ if ((r = ftell (fp)) != e+3)
+ {
+ printf ("%s: ftell returned %zu, expected %zu\n", __FUNCTION__, r, e+3);
+ return 1;
+ }
+
+ char exp[20];
+ sprintf (exp, "%s%d", str, 101);
+ if (memcmp (buf, exp, strlen (exp)) != 0)
+ {
+ printf ("%s: check failed:", __FUNCTION__);
+ printf ("\nexpected: ");
+ print_buffer (buf, sizeof (buf));
+ printf ("\nbuffer: ");
+ print_buffer (exp, sizeof (exp));
+ printf ("\n");
+ return 1;
+ }
+
+ fclose(fp);
+
+ return 0;
+}
+
+static int
do_test (void)
{
int ret = 0;
@@ -199,6 +310,11 @@ do_test (void)
ret += do_test_read_seek_negative ();
+ /* First test plus addend will fit in the define buffer of size 10. */
+ ret += do_test_write_append_2 ("test");
+ /* The second test will also fit, but not the final '\0'. */
+ ret += do_test_write_append_2 ("testing");
+
return ret;
}
This is an updated version on previous patch that fixes an issue regarding final '\0' that differs between writing and appending mode. For writing mode POSIX states null byte shall be written at the current position or at the end of the buffer, while for append a null byte shall be written at the end of the buffer if it fits. The implementation takes now in consideration by adding the final '\0' in append mode iff there is room for it. If noone opposes I will commit it by the end of the week. -- The fmemopen implementation does not account the file position correctly in append mode. The following example shows the failure: --- int main () { char buf[10] = "test"; FILE *fp = fmemopen (buf, 10, "a+"); fseek (fp, 0, SEEK_SET); int gr; if ((gr = getc (fp)) != 't' || (gr = getc (fp)) != 'e' || (gr = getc (fp)) != 's' || (gr = getc (fp)) != 't' || (gr = getc (fp)) != EOF) { printf ("%s: getc failed returned %i\n", __FUNCTION__, gr); return 1; } return 0; } --- This is due both how read and write operation update the buffer position, taking in consideration buffer lenght instead of maximum position defined by the open mode. This patch fixes it and also fixes fseek not returning EINVAL for invalid whence modes. Tested on x86_64 and i686. [BZ #20012] * libio/fmemopen.c (fmemopen_read): Use buffer maximum position, not length to calculate the buffer to read. (fmemopen_write): Set the buffer position based on bytes written. (fmemopen_seek): Return EINVAL for invalid whence modes. --- ChangeLog | 8 +++ libio/fmemopen.c | 28 +++++----- stdio-common/tst-fmemopen3.c | 118 ++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 140 insertions(+), 14 deletions(-)