empire/empserver
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Fix fillcache() and do_write() error handling

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Fix test for interrupted I/O.  Catch read hitting EOF unexpectedly.
Log errors in more detail.
This commit is contained in:
Markus Armbruster 2008-03-21 09:13:04 +01:00
parent 54f1e9a07f
commit 570ce80edf
1 changed files with 23 additions and 14 deletions
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37
src/lib/common/file.c
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@ -294,12 +294,12 @@ ef_read(int type, int id, void *into)
} }
/* /*
* Fill cache of EP with elements starting at ID. * Fill cache of file-backed EP with elements starting at ID.
* If any were read, return their number. * If any were read, return their number.
* Else return -1 and leave the cache unchanged. * Else return -1 and leave the cache unchanged.
*/ */
static int static int
fillcache(struct empfile *ep, int start) fillcache(struct empfile *ep, int id)
{ {
int n, ret; int n, ret;
char *p; char *p;
@ -307,21 +307,27 @@ fillcache(struct empfile *ep, int start)
if (CANT_HAPPEN(ep->fd < 0 || !ep->cache)) if (CANT_HAPPEN(ep->fd < 0 || !ep->cache))
return -1; return -1;
if (lseek(ep->fd, start * ep->size, SEEK_SET) == (off_t)-1) { if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
logerror("Error seeking %s (%s)", ep->file, strerror(errno)); logerror("Error seeking %s to elt %d (%s)",
ep->file, id, strerror(errno));
return -1; return -1;
} }
p = ep->cache; p = ep->cache;
n = ep->csize * ep->size; n = MIN(ep->csize, ep->fids - id) * ep->size;
while (n > 0) { while (n > 0) {
ret = read(ep->fd, p, n); ret = read(ep->fd, p, n);
if (ret < 0) { if (ret < 0) {
if (errno != EAGAIN) { if (errno != EINTR) {
logerror("Error reading %s (%s)", ep->file, strerror(errno)); logerror("Error reading %s elt %d (%s)",
ep->file,
id + (int)((p - ep->cache) / ep->size),
strerror(errno));
break; break;
} }
} else if (ret == 0) { } else if (ret == 0) {
logerror("Unexpected EOF reading %s elt %d",
ep->file, id + (int)((p - ep->cache) / ep->size));
break; break;
} else { } else {
p += ret; p += ret;
@ -332,15 +338,15 @@ fillcache(struct empfile *ep, int start)
if (p == ep->cache) if (p == ep->cache)
return -1; /* nothing read, old cache still ok */ return -1; /* nothing read, old cache still ok */
ep->baseid = start; ep->baseid = id;
ep->cids = (p - ep->cache) / ep->size; ep->cids = (p - ep->cache) / ep->size;
return ep->cids; return ep->cids;
} }
/* /*
* Write COUNT elements from BUF to EP, starting at ID. * Write COUNT elements starting at ID from BUF to file-backed EP.
* Set the timestamp to NOW if the table has those. * Set the timestamp to NOW if the table has those.
* Return 0 on success, -1 on error. * Return 0 on success, -1 on error (file may be corrupt then).
*/ */
static int static int
do_write(struct empfile *ep, void *buf, int id, int count, time_t now) do_write(struct empfile *ep, void *buf, int id, int count, time_t now)
@ -369,7 +375,8 @@ do_write(struct empfile *ep, void *buf, int id, int count, time_t now)
} }
if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) { if (lseek(ep->fd, id * ep->size, SEEK_SET) == (off_t)-1) {
logerror("Error seeking %s (%s)", ep->file, strerror(errno)); logerror("Error seeking %s to elt %d (%s)",
ep->file, id, strerror(errno));
return -1; return -1;
} }
@ -378,9 +385,11 @@ do_write(struct empfile *ep, void *buf, int id, int count, time_t now)
while (n > 0) { while (n > 0) {
ret = write(ep->fd, p, n); ret = write(ep->fd, p, n);
if (ret < 0) { if (ret < 0) {
if (errno != EAGAIN) { if (errno != EINTR) {
logerror("Error writing %s (%s)", ep->file, strerror(errno)); logerror("Error writing %s elt %d (%s)",
/* FIXME if this extended file, truncate back to old size */ ep->file,
id + (int)((p - (char *)buf) / ep->size),
strerror(errno));
return -1; return -1;
} }
} else { } else {