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Merge pull request #683 from openziti/feature/remove-sed-runtime-depe…
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…ndency

Feature/remove sed runtime dependency
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@sabedevops
sabedevops committed Jul 12, 2023
2 parents 4580e37 + a81b5e3 commit c1c117c
Showing 1 changed file with 98 additions and 39 deletions.
137 changes: 98 additions & 39 deletions programs/ziti-edge-tunnel/netif_driver/linux/resolvers.c
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Original file line number Diff line number Diff line change
Expand Up @@ -38,9 +38,9 @@
#define TRY_DL(dl_func) do{if ((dl_func) != 0) goto dl_error;} while(0)
#define RET_ON_FAIL(bool_func) do{if (!(bool_func)) return;} while(0)

static int sd_bus_is_acquired_name(sd_bus *bus, const char* bus_name);
static int sd_bus_is_acquired_name(sd_bus *bus, const char *bus_name);
static int detect_systemd_resolved_routing_domain_wildcard(sd_bus *bus, int32_t ifindex);
static bool set_systemd_resolved_link_setting(sd_bus *bus, const char* tun, const char* method, const char* method_type, ...);
static bool set_systemd_resolved_link_setting(sd_bus *bus, const char *tun, const char *method, const char *method_type, ...);

// libsystemd prototypes
static uv_once_t guard;
Expand Down Expand Up @@ -149,7 +149,7 @@ static int sd_bus_call_method_va(
return sd_bus_call_f(bus, m, 0, error, reply);
}

static int sd_bus_run_command(sd_bus *bus, const char *destination, const char* path, const char* interface, const char* command) {
static int sd_bus_run_command(sd_bus *bus, const char *destination, const char *path, const char *interface, const char *command) {
int r;
_cleanup_(sd_bus_error_free_wrapper) sd_bus_error error = SD_BUS_ERROR_NULL;

Expand All @@ -176,7 +176,7 @@ static int sd_bus_is_acquired_name(sd_bus *bus, const char* bus_name) {
int r;
_cleanup_(sd_bus_message_unrefp_f) sd_bus_message *reply = NULL;
_cleanup_(sd_bus_error_free_wrapper) sd_bus_error error = SD_BUS_ERROR_NULL;
char** acquired = NULL;
char **acquired = NULL;

r = sd_bus_call_method_f(
bus,
Expand Down Expand Up @@ -255,7 +255,7 @@ static int detect_systemd_resolved_routing_domain_wildcard(sd_bus *bus, int32_t

struct s_domain {
int32_t ifindex;
char * name;
char *name;
int is_routing_only;
};

Expand Down Expand Up @@ -289,7 +289,7 @@ static int detect_systemd_resolved_routing_domain_wildcard(sd_bus *bus, int32_t
return routing_only_wildcard_set;
}

static bool set_systemd_resolved_link_setting(sd_bus *bus, const char* tun, const char* method, const char* method_type, ...) {
static bool set_systemd_resolved_link_setting(sd_bus *bus, const char *tun, const char *method, const char *method_type, ...) {
_cleanup_(sd_bus_message_unrefp_f) sd_bus_message *reply = NULL;
_cleanup_(sd_bus_error_free_wrapper) sd_bus_error error = SD_BUS_ERROR_NULL;

Expand Down Expand Up @@ -353,7 +353,7 @@ bool try_libsystemd_resolver(void) {
return false;
}
if (r == 0) {
ZITI_LOG(INFO, "systemd-resolved selected as dns resolver manager");
ZITI_LOG(INFO, "systemd-resolved selected as DNS resolver manager");
return true;
}
} else {
Expand All @@ -363,7 +363,7 @@ bool try_libsystemd_resolver(void) {
return false;
}

void dns_update_systemd_resolved(const char* tun, unsigned int ifindex, const char* addr) {
void dns_update_systemd_resolved(const char *tun, unsigned int ifindex, const char *addr) {
int r;
struct in_addr inaddr;

Expand All @@ -375,7 +375,7 @@ void dns_update_systemd_resolved(const char* tun, unsigned int ifindex, const ch
r = inet_pton(AF_INET, addr, &inaddr);

if (r != 1) {
ZITI_LOG(ERROR, "Failed to translate dns address. Received: %s", addr);
ZITI_LOG(ERROR, "Failed to translate DNS address. Received: %s", addr);
return;
} else {
sscanf(addr, "%hhu.%hhu.%hhu.%hhu", &ay[0], &ay[1], &ay[2], &ay[3]);
Expand Down Expand Up @@ -414,10 +414,35 @@ void dns_update_systemd_resolved(const char* tun, unsigned int ifindex, const ch
}
#endif

void dns_update_resolvconf(const char* tun, unsigned int ifindex, const char* addr) {
void dns_update_resolvconf(const char *tun, unsigned int ifindex, const char *addr) {
run_command("echo 'nameserver %s' | %s -a %s", addr, RESOLVCONF, tun);
}

static bool make_copy(const char *src, const char *dst) {

uv_fs_t *req = (uv_fs_t *)malloc(sizeof(uv_fs_t));

ZITI_LOG(INFO, "attempting copy of: %s", src);

int ret = uv_fs_copyfile(uv_default_loop(), req, src, dst, UV_FS_COPYFILE_EXCL, NULL);

if (req->result < 0) {
if (req->result == UV_EEXIST) {
ZITI_LOG(DEBUG, "%s has already been copied", req->path);
} else {
ZITI_LOG(WARN, "could not create copy[%s]: %s", req->new_path, uv_strerror(req->result));
uv_fs_req_cleanup(req);
return false;
}
}

ZITI_LOG(INFO, "copy successful: %s", req->new_path);

uv_fs_req_cleanup(req);

return true;
}

static void cleanup_filep(FILE **file) {
if (*file != NULL) {
fclose(*file);
Expand All @@ -432,24 +457,33 @@ static void cleanup_bufferp(char **buffer) {
}
}

void dns_update_etc_resolv(const char* tun, unsigned int ifindex, const char* addr) {
const char* match = "nameserver ";
int replace_size = strlen(match) + strlen(addr) + 1;
_cleanup_(cleanup_bufferp) char* replace = (char *)malloc(replace_size);
void dns_update_etc_resolv(const char *tun, unsigned int ifindex, const char *addr) {
bool copy_r = make_copy(RESOLV_CONF_FILE, RESOLV_CONF_FILE ".bkp");

const char *match = "nameserver ";
off_t replace_size = strlen(match) + strlen(addr) + sizeof(char);

_cleanup_(cleanup_bufferp) char *replace = (char *)malloc((size_t)(replace_size + 1));
if (replace == NULL){
ZITI_LOG(ERROR, "error allocating replace buffer: %s", strerror(errno));
exit(EXIT_FAILURE);
}

strcpy(replace, match);
strcat(replace, addr);
strcat(replace, "\n");

_cleanup_(cleanup_filep) FILE* file = fopen(RESOLV_CONF_FILE, "r+");
_cleanup_(cleanup_filep) FILE *file = fopen(RESOLV_CONF_FILE, "r+");
if (file == NULL) {
ZITI_LOG(ERROR, "cannot open %s: %s", RESOLV_CONF_FILE, strerror(errno));
ZITI_LOG(WARN, "run as 'root' or manually update your resolver configuration. Ziti DNS must be the first resolver: %s", addr);
return;
}

char* buffer = NULL;
char *buffer = NULL;
size_t buffer_size;
ssize_t line_size;
long match_start_offset = -1;
off_t match_start_offset = -1;

while((line_size = getline(&buffer, &buffer_size, file)) != -1) {
if(strstr(buffer, match) != NULL) {
Expand All @@ -468,49 +502,74 @@ void dns_update_etc_resolv(const char* tun, unsigned int ifindex, const char* ad
exit(EXIT_FAILURE); \
} while(0)

#define CHECK_F_EOF(f) do { \
if ((f) == EOF) { \
ZITI_LOG(ERROR, "EOF received while writing file"); \
CLEANUP_ETC_RESOLV(); \
} \
} while (0)
struct stat file_stat;
if(stat(RESOLV_CONF_FILE, &file_stat) == -1){
ZITI_LOG(ERROR, "cannot stat %s: %s", RESOLV_CONF_FILE, strerror(errno));
CLEANUP_ETC_RESOLV();
}

// Slices everything after the matched line into a buffer,
// inserts the ziti nameserver line, and flushes the buffer back to the file.
if (match_start_offset >= 0) {
struct stat file_stat;
if(stat(RESOLV_CONF_FILE, &file_stat) == -1){
ZITI_LOG(ERROR, "cannot stat %s: %s", RESOLV_CONF_FILE, strerror(errno));
CLEANUP_ETC_RESOLV();
}

long remaining_size = file_stat.st_size - match_start_offset;
_cleanup_(cleanup_bufferp) char* remaining_content = malloc(remaining_size + 1);
off_t remaining_size = file_stat.st_size - match_start_offset;

_cleanup_(cleanup_bufferp) char *remaining_content = (char *)malloc(remaining_size + 1);
if (remaining_content == NULL) {
ZITI_LOG(ERROR, "error allocating %s file buffer: %s", RESOLV_CONF_FILE, strerror(errno));
ZITI_LOG(ERROR, "error allocating %s remaining content buffer: %s", RESOLV_CONF_FILE, strerror(errno));
CLEANUP_ETC_RESOLV();
}

fseek(file, match_start_offset, SEEK_SET);
if (fread(remaining_content, sizeof(char), remaining_size, file) != remaining_size) {
if (fread(remaining_content, sizeof(char), (size_t)remaining_size, file) != remaining_size) {
if (ferror(file) || feof(file)) {
ZITI_LOG(ERROR, "Error during file stream operation or EOF received.");
}
cleanup_bufferp(&remaining_content);
CLEANUP_ETC_RESOLV();
}
remaining_content[remaining_size] = '\0';

_cleanup_(cleanup_bufferp) char *rptr = realloc(replace, (size_t)(replace_size + remaining_size + 1));
if (rptr == NULL) {
ZITI_LOG(ERROR, "cannot realloc");
cleanup_bufferp(&remaining_content);
CLEANUP_ETC_RESOLV();
}

remaining_content[remaining_size] ='\0';
// Handle case in which realloc moves the memory block
// and calls free()
if (rptr != replace) {
replace = NULL;
}

strcat(rptr, remaining_content);

fseek(file, match_start_offset, SEEK_SET);
CHECK_F_EOF(fputs(replace, file));
CHECK_F_EOF(fputc('\n', file));
CHECK_F_EOF(fputs(remaining_content, file));

if (fputs(rptr, file) == EOF) {
ZITI_LOG(ERROR, "EOF received while writing file. Attempting to restore file to original content...");
fseek(file, match_start_offset, SEEK_SET);
if (fputs(remaining_content, file) == EOF) {
ZITI_LOG(ERROR, "EOF received while restoring file.");
if (copy_r) {
ZITI_LOG(ERROR, "Backup location: %s", RESOLV_CONF_FILE ".bkp");
}
cleanup_bufferp(&remaining_content);
cleanup_bufferp(&rptr);
CLEANUP_ETC_RESOLV();
}
}
ZITI_LOG(DEBUG, "Added ziti DNS resolver to %s", RESOLV_CONF_FILE);

return;
}

// If no nameservers directives to preppend, just append to the file.
CHECK_F_EOF(fputs(replace, file));
CHECK_F_EOF(fputc('\n', file));
// If no nameserver directives to prepend, just append to the file.
if (fputs(replace, file) == EOF) {
ZITI_LOG(ERROR, "EOF received while appending to: %s", RESOLV_CONF_FILE);
CLEANUP_ETC_RESOLV();
}
return;
}

Expand Down

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