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Added feature to customize resolv.conf file path at configure
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@mobrembski
mobrembski authored and Michał Obrembski committed Jan 19, 2021
1 parent b738a24 commit e9e6864
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Showing 2 changed files with 40 additions and 26 deletions.
6 changes: 6 additions & 0 deletions configure.ac
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Original file line number Diff line number Diff line change
Expand Up @@ -495,6 +495,12 @@ int main(int argc, char **argv){
AC_MSG_NOTICE([HAVE_SO_BINDTODEVICE... 0])
])

AC_ARG_WITH([resolvconf-config-file],
AS_HELP_STRING([--with-resolvconf-config-file],
[Set the path to the resolv.conf config file. \
Default is /etc/resolv.conf.]),
AC_DEFINE_UNQUOTED([RESOLV_CONF_FILE_PATH],["$withval"])
)

# prepare to get rid of obsolete code (FortiOS 4)
AC_ARG_ENABLE([obsolete],
Expand Down
60 changes: 34 additions & 26 deletions src/ipv4.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,10 @@ static char show_route_buffer[SHOW_ROUTE_BUFFER_SIZE];
#define ERR_IPV4_NO_SUCH_ROUTE -4
#define ERR_IPV4_PROC_NET_ROUTE -5

#ifndef RESOLV_CONF_FILE_PATH
#define RESOLV_CONF_FILE_PATH /etc/resolv.conf
#endif

static inline const char *err_ipv4_str(int code)
{
if (code == ERR_IPV4_SEE_ERRNO)
Expand Down Expand Up @@ -1120,36 +1124,36 @@ int ipv4_add_nameservers_to_resolv_conf(struct tunnel *tunnel)
free(resolvconf_call);
} else {
#endif
log_debug("Attempting to modify /etc/resolv.conf directly.\n");
file = fopen("/etc/resolv.conf", "r+");
log_debug("Attempting to modify " RESOLV_CONF_FILE_PATH " directly.\n");
file = fopen(RESOLV_CONF_FILE_PATH, "r+");
if (file == NULL) {
log_warn("Could not open /etc/resolv.conf (%s).\n",
log_warn("Could not open " RESOLV_CONF_FILE_PATH " (%s).\n",
strerror(errno));
return 1;
}

if (fstat(fileno(file), &stat) == -1) {
log_warn("Could not stat /etc/resolv.conf (%s).\n",
log_warn("Could not stat " RESOLV_CONF_FILE_PATH " (%s).\n",
strerror(errno));
goto err_close;
}

if (stat.st_size == 0) {
log_warn("Could not read /etc/resolv.conf (%s).\n",
log_warn("Could not read " RESOLV_CONF_FILE_PATH " (%s).\n",
"Empty file");
goto err_close;
}

buffer = malloc(stat.st_size + 1);
if (buffer == NULL) {
log_warn("Could not read /etc/resolv.conf (%s).\n",
log_warn("Could not read " RESOLV_CONF_FILE_PATH " (%s).\n",
strerror(errno));
goto err_close;
}

// Copy all file contents at once
if (fread(buffer, stat.st_size, 1, file) != 1) {
log_warn("Could not read /etc/resolv.conf.\n");
log_warn("Could not read "RESOLV_CONF_FILE_PATH ".\n");
goto err_free;
}

Expand Down Expand Up @@ -1189,24 +1193,24 @@ int ipv4_add_nameservers_to_resolv_conf(struct tunnel *tunnel)
line = strtok_r(NULL, "\n", &saveptr)) {
if (strcmp(line, ns1) == 0) {
tunnel->ipv4.ns1_was_there = 1;
log_debug("ns1 already present in /etc/resolv.conf.\n");
log_debug("ns1 already present in " RESOLV_CONF_FILE_PATH ".\n");
}
}

if (tunnel->ipv4.ns1_was_there == 0)
log_debug("Adding \"%s\", to /etc/resolv.conf.\n", ns1);
log_debug("Adding \"%s\", to " RESOLV_CONF_FILE_PATH " .\n", ns1);

for (const char *line = strtok_r(buffer, "\n", &saveptr);
line != NULL;
line = strtok_r(NULL, "\n", &saveptr)) {
if (strcmp(line, ns2) == 0) {
tunnel->ipv4.ns2_was_there = 1;
log_debug("ns2 already present in /etc/resolv.conf.\n");
log_debug("ns2 already present in " RESOLV_CONF_FILE_PATH ".\n");
}
}

if (tunnel->ipv4.ns2_was_there == 0)
log_debug("Adding \"%s\", to /etc/resolv.conf.\n", ns2);
log_debug("Adding \"%s\", to " RESOLV_CONF_FILE_PATH ".\n", ns2);

if (dns_suffix[0] == '\0') {
tunnel->ipv4.dns_suffix_was_there = -1;
Expand All @@ -1217,17 +1221,18 @@ int ipv4_add_nameservers_to_resolv_conf(struct tunnel *tunnel)
if (dns_suffix[0] != '\0'
&& strcmp(line, dns_suffix) == 0) {
tunnel->ipv4.dns_suffix_was_there = 1;
log_debug("dns_suffix already present in /etc/resolv.conf.\n");
log_debug("dns_suffix already present in " RESOLV_CONF_FILE_PATH ".\n");
}
}
}

if (tunnel->ipv4.dns_suffix_was_there == 0)
log_debug("Adding \"%s\", to /etc/resolv.conf.\n", dns_suffix);
log_debug("Adding \"%s\", to " RESOLV_CONF_FILE_PATH ".\n",
dns_suffix);

rewind(file);
if (fread(buffer, stat.st_size, 1, file) != 1) {
log_warn("Could not read /etc/resolv.conf.\n");
log_warn("Could not read " RESOLV_CONF_FILE_PATH ".\n");
goto err_free;
}

Expand Down Expand Up @@ -1263,7 +1268,7 @@ int ipv4_add_nameservers_to_resolv_conf(struct tunnel *tunnel)
if (use_resolvconf == 0) {
#endif
if (fclose(file))
log_warn("Could not close /etc/resolv.conf: %s\n",
log_warn("Could not close " RESOLV_CONF_FILE_PATH": %s\n",
strerror(errno));
#if HAVE_RESOLVCONF
} else {
Expand Down Expand Up @@ -1321,29 +1326,29 @@ int ipv4_del_nameservers_from_resolv_conf(struct tunnel *tunnel)
}
#endif

file = fopen("/etc/resolv.conf", "r+");
file = fopen(RESOLV_CONF_FILE_PATH, "r+");
if (file == NULL) {
log_warn("Could not open /etc/resolv.conf (%s).\n",
log_warn("Could not open " RESOLV_CONF_FILE_PATH " (%s).\n",
strerror(errno));
return 1;
}

if (fstat(fileno(file), &stat) == -1) {
log_warn("Could not stat /etc/resolv.conf (%s).\n",
log_warn("Could not stat " RESOLV_CONF_FILE_PATH " (%s).\n",
strerror(errno));
goto err_close;
}

buffer = malloc(stat.st_size + 1);
if (buffer == NULL) {
log_warn("Could not read /etc/resolv.conf (%s).\n",
log_warn("Could not read " RESOLV_CONF_FILE_PATH " (%s).\n",
strerror(errno));
goto err_close;
}

// Copy all file contents at once
if (fread(buffer, stat.st_size, 1, file) != 1) {
log_warn("Could not read /etc/resolv.conf.\n");
log_warn("Could not read " RESOLV_CONF_FILE_PATH ".\n");
goto err_free;
}

Expand All @@ -1365,9 +1370,9 @@ int ipv4_del_nameservers_from_resolv_conf(struct tunnel *tunnel)
strncat(dns_suffix, tunnel->ipv4.dns_suffix, MAX_DOMAIN_LENGTH);
}

file = freopen("/etc/resolv.conf", "w", file);
file = freopen(RESOLV_CONF_FILE_PATH, "w", file);
if (file == NULL) {
log_warn("Could not reopen /etc/resolv.conf (%s).\n",
log_warn("Could not reopen " RESOLV_CONF_FILE_PATH " (%s).\n",
strerror(errno));
goto err_free;
}
Expand All @@ -1377,13 +1382,16 @@ int ipv4_del_nameservers_from_resolv_conf(struct tunnel *tunnel)
line = strtok_r(NULL, "\n", &saveptr)) {
if (ns1[0] != '\0' && strcmp(line, ns1) == 0
&& (tunnel->ipv4.ns1_was_there == 0)) {
log_debug("Deleting \"%s\" from /etc/resolv.conf.\n", ns1);
log_debug("Deleting \"%s\" from " RESOLV_CONF_FILE_PATH ".\n",
ns1);
} else if (ns2[0] != '\0' && strcmp(line, ns2) == 0
&& (tunnel->ipv4.ns2_was_there == 0)) {
log_debug("Deleting \"%s\" from /etc/resolv.conf.\n", ns2);
log_debug("Deleting \"%s\" from " RESOLV_CONF_FILE_PATH ".\n",
ns2);
} else if (dns_suffix[0] != '\0' && strcmp(line, dns_suffix) == 0
&& (tunnel->ipv4.dns_suffix_was_there == 0)) {
log_debug("Deleting \"%s\" from /etc/resolv.conf.\n", dns_suffix);
log_debug("Deleting \"%s\" from " RESOLV_CONF_FILE_PATH ".\n",
dns_suffix);
} else {
fputs(line, file);
fputs("\n", file);
Expand All @@ -1396,7 +1404,7 @@ int ipv4_del_nameservers_from_resolv_conf(struct tunnel *tunnel)
free(buffer);
err_close:
if (file && fclose(file))
log_warn("Could not close /etc/resolv.conf (%s).\n",
log_warn("Could not close " RESOLV_CONF_FILE_PATH " (%s).\n",
strerror(errno));
return ret;
}

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