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78 lines
1.7 KiB
C
78 lines
1.7 KiB
C
#include "gossip_store.h"
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#include <ccan/endian/endian.h>
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#include <ccan/read_write_all/read_write_all.h>
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#include <common/status.h>
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#include <fcntl.h>
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#include <unistd.h>
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#define GOSSIP_STORE_FILENAME "gossip_store"
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struct gossip_store {
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int fd;
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off_t read_pos, write_pos;
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};
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static void gossip_store_destroy(struct gossip_store *gs)
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{
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close(gs->fd);
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}
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struct gossip_store *gossip_store_new(const tal_t *ctx)
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{
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struct gossip_store *gs = tal(ctx, struct gossip_store);
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gs->fd = open(GOSSIP_STORE_FILENAME, O_RDWR|O_APPEND|O_CREAT, 0600);
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gs->read_pos = 0;
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gs->write_pos = lseek(gs->fd, 0, SEEK_END);
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tal_add_destructor(gs, gossip_store_destroy);
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return gs;
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}
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void gossip_store_append(struct gossip_store *gs, const u8 *msg)
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{
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u16 msglen = tal_len(msg);
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beint16_t belen = cpu_to_be16(msglen);
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if (pwrite(gs->fd, &belen, sizeof(belen), gs->write_pos) != 2 ||
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pwrite(gs->fd, msg, msglen, gs->write_pos + 2) != msglen) {
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return;
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} else
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gs->write_pos += 2 + msglen;
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}
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const u8 *gossip_store_read_next(const tal_t *ctx, struct gossip_store *gs)
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{
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beint16_t belen;
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u16 msglen;
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u8 *msg;
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/* Did we already reach the end of the gossip_store? */
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if (gs->read_pos == -1)
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return NULL;
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/* Can we read one message? */
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if (pread(gs->fd, &belen, sizeof(belen), gs->read_pos) != 2) {
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gs->read_pos = -1;
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return NULL;
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}
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msglen = be16_to_cpu(belen);
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msg = tal_arr(ctx, u8, msglen);
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if (!pread(gs->fd, msg, msglen, gs->read_pos + 2)) {
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status_trace("Short read from gossip-store, expected lenght %d",
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msglen);
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/* Reset write_pos to truncate this message and disable future
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* reads */
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gs->write_pos = gs->read_pos;
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gs->read_pos = -1;
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ftruncate(gs->fd, gs->write_pos);
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} else
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gs->read_pos += 2 + msglen;
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return msg;
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}
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