78 lines
2.5 KiB
C
78 lines
2.5 KiB
C
// Copyright 2011-2018 Nicholas J. Kain <njkain at gmail dot com>
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// SPDX-License-Identifier: MIT
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <arpa/inet.h>
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#include <errno.h>
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#include <limits.h>
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#include "nk/log.h"
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#include "nk/io.h"
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#include "leasefile.h"
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#include "ndhc.h"
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static int leasefilefd = -1;
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static void get_leasefile_path(char *leasefile, size_t dlen, char *ifname)
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{
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int splen = snprintf(leasefile, dlen, "%s/LEASE-%s",
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state_dir, ifname);
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if (splen < 0)
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suicide("%s: (%s) snprintf failed; return=%d",
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client_config.interface, __func__, splen);
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if ((size_t)splen >= dlen)
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suicide("%s: (%s) snprintf dest buffer too small %d >= %zu",
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client_config.interface, __func__, splen, sizeof dlen);
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}
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void open_leasefile(void)
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{
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char leasefile[PATH_MAX];
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get_leasefile_path(leasefile, sizeof leasefile, client_config.interface);
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leasefilefd = open(leasefile, O_WRONLY|O_TRUNC|O_CREAT, 0644);
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if (leasefilefd < 0)
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suicide("%s: (%s) Failed to create lease file '%s': %s",
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client_config.interface, __func__, leasefile, strerror(errno));
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}
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void write_leasefile(struct in_addr ipnum)
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{
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char ip[INET_ADDRSTRLEN];
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char out[INET_ADDRSTRLEN*2];
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if (leasefilefd < 0) {
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log_line("%s: (%s) leasefile fd < 0; no leasefile will be written",
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client_config.interface, __func__);
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return;
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}
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inet_ntop(AF_INET, &ipnum, ip, sizeof ip);
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ssize_t olen = snprintf(out, sizeof out, "%s\n", ip);
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if (olen < 0 || (size_t)olen >= sizeof ip) {
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log_line("%s: (%s) snprintf failed; return=%zd",
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client_config.interface, __func__, olen);
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return;
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}
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if (safe_ftruncate(leasefilefd, 0)) {
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log_line("%s: (%s) Failed to truncate lease file: %s",
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client_config.interface, __func__, strerror(errno));
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return;
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}
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if (lseek(leasefilefd, 0, SEEK_SET) == (off_t)-1) {
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log_line("%s: (%s) Failed to seek to start of lease file: %s",
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client_config.interface, __func__, strerror(errno));
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return;
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}
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size_t outlen = strlen(out);
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ssize_t ret = safe_write(leasefilefd, out, outlen);
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if (ret < 0 || (size_t)ret != outlen)
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log_line("%s: (%s) Failed to write ip to lease file.",
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client_config.interface, __func__);
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else
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fsync(leasefilefd);
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}
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