Skip to content

Commit

Permalink
Simplify concatenation of formatted strings (#232)
Browse files Browse the repository at this point in the history 
Instead of keeping track of offset into and length of buffer,
keep track of pointers to next input and to end of buffer.
This means one less subtraction in every call to g_snprintf()
and occationally statements that don't have to span several lines.

The --tlsverify flag was also moved from tls.c to the main file.
  • Loading branch information
@killenheladagen
killenheladagen authored Apr 22, 2024
1 parent e67c051 commit 6173697
Show file tree
Hide file tree
Showing 3 changed files with 40 additions and 58 deletions.
89 changes: 35 additions & 54 deletions app/dockerdwrapper.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -501,7 +501,8 @@ check_child_process_exit_code_and_clean_up(GPid pid, gint status, gpointer app_s
// Return a command line with space-delimited argument based on the current settings.
static const char* build_daemon_args(const struct settings* settings, AXParameter* param_handle) {
static gchar args[1024]; // Pointer to args returned to caller on success.
const gsize args_len = sizeof(args);
const char* args_end = args + sizeof(args);
char* args_wr = args; // Points to location of next write

const char* data_root = settings->data_root;
const bool use_tls = settings->use_tls;
Expand All @@ -510,7 +511,6 @@ static const char* build_daemon_args(const struct settings* settings, AXParamete

gsize msg_len = 128;
gchar msg[msg_len];
guint args_offset = 0;

g_autofree char* log_level = get_parameter_value(param_handle, PARAM_DOCKERD_LOG_LEVEL);

Expand All @@ -523,42 +523,36 @@ static const char* build_daemon_args(const struct settings* settings, AXParamete
IPbuffer = inet_ntoa(*((struct in_addr*)host_entry->h_addr_list[0]));

// construct the rootlesskit command
args_offset += g_snprintf(args + args_offset,
args_len - args_offset,
"%s %s %s %s %s %s %s %s %s",
"rootlesskit",
"--subid-source=static",
"--net=slirp4netns",
"--disable-host-loopback",
"--copy-up=/etc",
"--copy-up=/run",
"--propagation=rslave",
"--port-driver slirp4netns",
/* don't use same range as company proxy */
"--cidr=10.0.3.0/24");
args_wr += g_snprintf(args_wr,
args_end - args_wr,
"%s %s %s %s %s %s %s %s %s",
"rootlesskit",
"--subid-source=static",
"--net=slirp4netns",
"--disable-host-loopback",
"--copy-up=/etc",
"--copy-up=/run",
"--propagation=rslave",
"--port-driver slirp4netns",
/* don't use same range as company proxy */
"--cidr=10.0.3.0/24");

if (strcmp(log_level, "debug") == 0) {
args_offset += g_snprintf(args + args_offset, args_len - args_offset, " %s", "--debug");
args_wr += g_snprintf(args_wr, args_end - args_wr, " %s", "--debug");
}

const uint port = use_tls ? 2376 : 2375;
args_offset += g_snprintf(args + args_offset,
args_len - args_offset,
" -p %s:%d:%d/tcp",
IPbuffer,
port,
port);
args_wr += g_snprintf(args_wr, args_end - args_wr, " -p %s:%d:%d/tcp", IPbuffer, port, port);

// add dockerd command
args_offset += g_snprintf(args + args_offset,
args_len - args_offset,
" dockerd %s",
"--config-file " APP_LOCALDATA "/" DAEMON_JSON);
args_wr += g_snprintf(args_wr,
args_end - args_wr,
" dockerd %s",
"--config-file " APP_LOCALDATA "/" DAEMON_JSON);

g_strlcpy(msg, "Starting dockerd", msg_len);

args_offset +=
g_snprintf(args + args_offset, args_len - args_offset, " --log-level=%s", log_level);
args_wr += g_snprintf(args_wr, args_end - args_wr, " --log-level=%s", log_level);

if (use_ipc_socket) {
g_strlcat(msg, " with IPC socket and", msg_len);
Expand All @@ -567,39 +561,28 @@ static const char* build_daemon_args(const struct settings* settings, AXParamete
// However, rootlesskit maps the user's primary group to the root group, so "--group 0"
// means the socket will belong to the user's primary group.
g_autofree char* ipc_socket = xdg_runtime_file("docker.sock");
args_offset += g_snprintf(args + args_offset,
args_len - args_offset,
" --group 0 -H unix://%s",
ipc_socket);
args_wr += g_snprintf(args_wr, args_end - args_wr, " --group 0 -H unix://%s", ipc_socket);
} else {
g_strlcat(msg, " without IPC socket and", msg_len);
}

if (use_tcp_socket) {
g_strlcat(msg, " with TCP socket", msg_len);
g_strlcat(msg, use_tls ? " in TLS mode" : " in unsecured mode", msg_len);
const uint port = use_tls ? 2376 : 2375;
args_offset +=
g_snprintf(args + args_offset, args_len - args_offset, " -H tcp://0.0.0.0:%d", port);
if (use_tls) {
args_offset += g_snprintf(args + args_offset,
args_len - args_offset,
" %s",
tls_args_for_dockerd());
g_strlcat(msg, " in TLS mode", msg_len);
} else {
args_offset += g_snprintf(args + args_offset, args_len - args_offset, " --tls=false");
g_strlcat(msg, " in unsecured mode", msg_len);
}
args_wr += g_snprintf(args_wr, args_end - args_wr, " -H tcp://0.0.0.0:%d", port);
const char* tls_arg = use_tls ? "--tlsverify=true" : "--tls=false";
args_wr += g_snprintf(args_wr, args_end - args_wr, " %s", tls_arg);
if (use_tls)
args_wr += g_snprintf(args_wr, args_end - args_wr, " %s", tls_file_dockerd_args());
} else {
g_strlcat(msg, " without TCP socket", msg_len);
}

{
g_autofree char* data_root_msg = g_strdup_printf(" using %s as storage.", data_root);
g_strlcat(msg, data_root_msg, msg_len);
args_offset +=
g_snprintf(args + args_offset, args_len - args_offset, " --data-root %s", data_root);
}
g_autofree char* data_root_msg = g_strdup_printf(" using %s as storage.", data_root);
g_strlcat(msg, data_root_msg, msg_len);
args_wr += g_snprintf(args_wr, args_end - args_wr, " --data-root %s", data_root);

log_info("%s", msg);
return args;
}
Expand All @@ -611,13 +594,11 @@ static bool start_dockerd(const struct settings* settings, struct app_state* app
GError* error = NULL;
bool result = false;
bool return_value = false;
const char* args;
gchar** args_split = NULL;

args = build_daemon_args(settings, param_handle);
const char* args = build_daemon_args(settings, param_handle);

log_debug("Sending daemon start command: %s", args);
args_split = g_strsplit(args, " ", 0);
char** args_split = g_strsplit(args, " ", 0);
result = g_spawn_async(NULL,
args_split,
NULL,
Expand Down
7 changes: 4 additions & 3 deletions app/tls.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,18 +58,19 @@ const char* tls_file_description(const char* filename) {
return NULL;
}

const char* tls_args_for_dockerd(void) {
const char* tls_file_dockerd_args(void) {
static char args[512]; // Too small buffer will cause truncated options, nothing more.
const char* end = args + sizeof(args);
char* ptr = args + g_snprintf(args, end - args, "--tlsverify");
char* ptr = args;

for (size_t i = 0; i < NUM_TLS_CERTS; ++i)
ptr += g_snprintf(ptr,
end - ptr,
" %s %s/%s",
"%s %s/%s ",
tls_certs[i].dockerd_option,
TLS_CERT_PATH,
tls_certs[i].filename);
ptr[-1] = '\0'; // Remove space after last item.
return args;
}

Expand Down
2 changes: 1 addition & 1 deletion app/tls.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,5 +4,5 @@
bool tls_missing_certs(void);
void tls_log_missing_cert_warnings(void);
const char* tls_file_description(const char* filename);
const char* tls_args_for_dockerd(void);
const char* tls_file_dockerd_args(void);
bool tls_file_has_correct_format(const char* filename, const char* path_to_file);

0 comments on commit 6173697

Please sign in to comment.