tdb2: remove looping for read on normal files.

Simply assume that any short read on a TDB in an I/O error.

diff --git a/ccan/tdb2/io.c b/ccan/tdb2/io.c
index 3a261a4053ec9fb369077664c66c88ed69e484b8..999922b12e517c63be16ce1b20d7d22d077f9acc 100644 (file)
--- a/ccan/tdb2/io.c
+++ b/ccan/tdb2/io.c
@@ -225,44 +225,6 @@ bool tdb_pwrite_all(int fd, const void *buf, size_t len, tdb_off_t off)
        return true;
 }
 
-/* Even on files, we can get partial reads due to signals. */
-bool tdb_pread_all(int fd, void *buf, size_t len, tdb_off_t off)
-{
-       while (len) {
-               ssize_t ret;
-               ret = pread(fd, buf, len, off);
-               if (ret < 0)
-                       return false;
-               if (ret == 0) {
-                       /* ETOOSHORT? */
-                       errno = EWOULDBLOCK;
-                       return false;
-               }
-               buf = (char *)buf + ret;
-               off += ret;
-               len -= ret;
-       }
-       return true;
-}
-
-bool tdb_read_all(int fd, void *buf, size_t len)
-{
-       while (len) {
-               ssize_t ret;
-               ret = read(fd, buf, len);
-               if (ret < 0)
-                       return false;
-               if (ret == 0) {
-                       /* ETOOSHORT? */
-                       errno = EWOULDBLOCK;
-                       return false;
-               }
-               buf = (char *)buf + ret;
-               len -= ret;
-       }
-       return true;
-}
-
 /* write a lump of data at a specified offset */
 static int tdb_write(struct tdb_context *tdb, tdb_off_t off, 
                     const void *buf, tdb_len_t len)
@@ -305,13 +267,14 @@ static int tdb_read(struct tdb_context *tdb, tdb_off_t off, void *buf,
        if (tdb->map_ptr) {
                memcpy(buf, off + (char *)tdb->map_ptr, len);
        } else {
-               if (!tdb_pread_all(tdb->fd, buf, len, off)) {
+               ssize_t r = pread(tdb->fd, buf, len, off);
+               if (r != len) {
                        tdb_logerr(tdb, TDB_ERR_IO, TDB_DEBUG_FATAL,
-                                  "tdb_read failed at %zu "
+                                  "tdb_read failed with %zi at %zu "
                                   "len=%zu (%s) map_size=%zu",
-                                (size_t)off, (size_t)len,
-                                strerror(errno),
-                                (size_t)tdb->map_size);
+                                  r, (size_t)off, (size_t)len,
+                                  strerror(errno),
+                                  (size_t)tdb->map_size);
                        return -1;
                }
        }

diff --git a/ccan/tdb2/private.h b/ccan/tdb2/private.h
index de832af667402eb3efb609954fcaaf77fd61c98b..1092f171427cbbd097b9738db7fad6ceedb2c066 100644 (file)
--- a/ccan/tdb2/private.h
+++ b/ccan/tdb2/private.h
@@ -476,8 +476,6 @@ tdb_off_t tdb_find_zero_off(struct tdb_context *tdb, tdb_off_t off,
 
 /* Even on files, we can get partial writes due to signals. */
 bool tdb_pwrite_all(int fd, const void *buf, size_t len, tdb_off_t off);
-bool tdb_pread_all(int fd, void *buf, size_t len, tdb_off_t off);
-bool tdb_read_all(int fd, void *buf, size_t len);
 
 /* Allocate and make a copy of some offset. */
 void *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len);

diff --git a/ccan/tdb2/tdb.c b/ccan/tdb2/tdb.c
index dfa68451e51a878d4be75f5431121ff1f012b9d4..e3b579d0f259ad94498fe740f84bef7dc52d9d2b 100644 (file)
--- a/ccan/tdb2/tdb.c
+++ b/ccan/tdb2/tdb.c
@@ -22,6 +22,24 @@ static bool tdb_already_open(dev_t device, ino_t ino)
        return false;
 }
 
+static bool read_all(int fd, void *buf, size_t len)
+{
+       while (len) {
+               ssize_t ret;
+               ret = read(fd, buf, len);
+               if (ret < 0)
+                       return false;
+               if (ret == 0) {
+                       /* ETOOSHORT? */
+                       errno = EWOULDBLOCK;
+                       return false;
+               }
+               buf = (char *)buf + ret;
+               len -= ret;
+       }
+       return true;
+}
+
 static uint64_t random_number(struct tdb_context *tdb)
 {
        int fd;
@@ -30,7 +48,7 @@ static uint64_t random_number(struct tdb_context *tdb)
 
        fd = open("/dev/urandom", O_RDONLY);
        if (fd >= 0) {
-               if (tdb_read_all(fd, &ret, sizeof(ret))) {
+               if (read_all(fd, &ret, sizeof(ret))) {
                        tdb_logerr(tdb, TDB_SUCCESS, TDB_DEBUG_TRACE,
                                 "tdb_open: random from /dev/urandom");
                        close(fd);
@@ -153,6 +171,7 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
        int saved_errno = 0;
        uint64_t hash_test;
        unsigned v;
+       ssize_t rlen;
        struct tdb_header hdr;
        struct tdb_attribute_seed *seed = NULL;
 
@@ -253,17 +272,25 @@ struct tdb_context *tdb_open(const char *name, int tdb_flags,
                goto fail;
        }
 
-       if (!tdb_pread_all(tdb->fd, &hdr, sizeof(hdr), 0)
-           || strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
-               if (!(open_flags & O_CREAT)) {
-                       tdb_logerr(tdb, TDB_ERR_IO, TDB_DEBUG_ERROR,
-                                  "tdb_open: %s is not a tdb file", name);
-                       goto fail;
-               }
+       /* If they used O_TRUNC, read will return 0. */
+       rlen = read(tdb->fd, &hdr, sizeof(hdr));
+       if (rlen == 0 && (open_flags & O_CREAT)) {
                if (tdb_new_database(tdb, seed, &hdr) == -1) {
                        goto fail;
                }
-       } else if (hdr.version != TDB_VERSION) {
+       } else if (rlen < 0) {
+               tdb_logerr(tdb, TDB_ERR_IO, TDB_DEBUG_ERROR,
+                          "tdb_open: error %s reading %s",
+                          strerror(errno), name);
+               goto fail;
+       } else if (rlen < sizeof(hdr)
+                  || strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
+               tdb_logerr(tdb, TDB_ERR_IO, TDB_DEBUG_ERROR,
+                          "tdb_open: %s is not a tdb file", name);
+               goto fail;
+       }
+
+       if (hdr.version != TDB_VERSION) {
                if (hdr.version == bswap_64(TDB_VERSION))
                        tdb->flags |= TDB_CONVERT;
                else {