tdb2: remove looping for write

[ccan] / ccan / tdb2 / tdb.c

diff --git a/ccan/tdb2/tdb.c b/ccan/tdb2/tdb.c
index dfa68451e51a878d4be75f5431121ff1f012b9d4..1aa3baa46c24471033af359dba192ab82e3747a3 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);
@@ -83,6 +101,7 @@ static int tdb_new_database(struct tdb_context *tdb,
        /* We make it up in memory, then write it out if not internal */
        struct new_database newdb;
        unsigned int magic_len;
+       ssize_t rlen;
 
        /* Fill in the header */
        newdb.hdr.version = TDB_VERSION;
@@ -135,10 +154,13 @@ static int tdb_new_database(struct tdb_context *tdb,
        if (ftruncate(tdb->fd, 0) == -1)
                return -1;
 
-       if (!tdb_pwrite_all(tdb->fd, &newdb, sizeof(newdb), 0)) {
+       rlen = write(tdb->fd, &newdb, sizeof(newdb));
+       if (rlen != sizeof(newdb)) {
+               if (rlen >= 0)
+                       errno = ENOSPC;
                tdb_logerr(tdb, TDB_ERR_IO, TDB_DEBUG_FATAL,
-                          "tdb_new_database: failed to write: %s",
-                          strerror(errno));
+                          "tdb_new_database: %zi writing header: %s",
+                          rlen, strerror(errno));
                return -1;
        }
        return 0;
@@ -153,6 +175,7 @@ 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 +276,25 @@ 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 {