aboutsummaryrefslogtreecommitdiff
path: root/kms/client/kms_client.c
blob: aab5b01ded76bb87e57d09bfe6adb2578267d477 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
#include "kms_client.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <stdbool.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <sys/capability.h>

static bool generate_random_characters(char *buffer, int buffer_size, const char *alphabet, size_t alphabet_size) {
    int fd = open("/dev/urandom", O_RDONLY);
    if(fd == -1) {
        perror("/dev/urandom");
        return false;
    }

    if(read(fd, buffer, buffer_size) < buffer_size) {
        fprintf(stderr, "Failed to read %d bytes from /dev/urandom\n", buffer_size);
        close(fd);
        return false;
    }

    for(int i = 0; i < buffer_size; ++i) {
        unsigned char c = *(unsigned char*)&buffer[i];
        buffer[i] = alphabet[c % alphabet_size];
    }

    close(fd);
    return true;
}

static int send_msg_to_server(int server_fd, gsr_kms_request *request) {
    struct iovec iov;
    iov.iov_base = request;
    iov.iov_len = sizeof(*request);

    struct msghdr request_message = {0};
    request_message.msg_iov = &iov;
    request_message.msg_iovlen = 1;

    return sendmsg(server_fd, &request_message, 0);
}

static int recv_msg_from_server(int server_fd, gsr_kms_response *response) {
    struct iovec iov;
    iov.iov_base = response;
    iov.iov_len = sizeof(*response);

    struct msghdr response_message = {0};
    response_message.msg_iov = &iov;
    response_message.msg_iovlen = 1;

    char cmsgbuf[CMSG_SPACE(sizeof(int) * GSR_KMS_MAX_PLANES)];
    memset(cmsgbuf, 0, sizeof(cmsgbuf));
    response_message.msg_control = cmsgbuf;
    response_message.msg_controllen = sizeof(cmsgbuf);

    int res = recvmsg(server_fd, &response_message, MSG_WAITALL);
    if(res <= 0)
        return res;

    if(response->num_fds > 0) {
        struct cmsghdr *cmsg = CMSG_FIRSTHDR(&response_message);
        if(cmsg) {
            int *fds = (int*)CMSG_DATA(cmsg);
            for(int i = 0; i < response->num_fds; ++i) {
                response->fds[i].fd = fds[i];
            }
        } else {
            for(int i = 0; i < response->num_fds; ++i) {
                response->fds[i].fd = 0;
            }
        }
    }

    return res;
}

/* We have to use $HOME because in flatpak there is no simple path that is accessible, read and write, that multiple flatpak instances can access */
static bool create_socket_path(char *output_path, size_t output_path_size) {
    const char *home = getenv("HOME");
    if(!home)
        home = "/tmp";

    char random_characters[11];
    random_characters[10] = '\0';
    if(!generate_random_characters(random_characters, 10, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789", 62))
        return false;

    snprintf(output_path, output_path_size, "%s/.gsr-kms-socket-%s", home, random_characters);
    return true;
}

static void strncpy_safe(char *dst, const char *src, int len) {
    int src_len = strlen(src);
    int min_len = src_len;
    if(len - 1 < min_len)
        min_len = len - 1;
    memcpy(dst, src, min_len);
    dst[min_len] = '\0';
}

static bool find_program_in_path(const char *program_name, char *filepath, int filepath_len) {
    const char *path = getenv("PATH");
    if(!path)
        return false;

    int program_name_len = strlen(program_name);
    const char *end = path + strlen(path);
    while(path != end) {
        const char *part_end = strchr(path, ':');
        const char *next = part_end;
        if(part_end) {
            next = part_end + 1;
        } else {
            part_end = end;
            next = end;
        }

        int len = part_end - path;
        if(len + 1 + program_name_len < filepath_len) {
            memcpy(filepath, path, len);
            filepath[len] = '/';
            memcpy(filepath + len + 1, program_name, program_name_len);
            filepath[len + 1 + program_name_len] = '\0';

            if(access(filepath, F_OK) == 0)
                return true;
        }

        path = next;
    }

    return false;
}

int gsr_kms_client_init(gsr_kms_client *self, const char *card_path) {
    int result = -1;
    self->kms_server_pid = -1;
    self->socket_fd = -1;
    self->client_fd = -1;
    self->socket_path[0] = '\0';
    struct sockaddr_un local_addr = {0};
    struct sockaddr_un remote_addr = {0};

    if(!create_socket_path(self->socket_path, sizeof(self->socket_path))) {
        fprintf(stderr, "gsr error: gsr_kms_client_init: failed to create path to kms socket\n");
        return -1;
    }

    char server_filepath[PATH_MAX];
    if(!find_program_in_path("gsr-kms-server", server_filepath, sizeof(server_filepath))) {
        fprintf(stderr, "gsr error: gsr_kms_client_init: gsr-kms-server is not installed\n");
        return -1;
    }

    bool has_perm = 0;
    const bool inside_flatpak = getenv("FLATPAK_ID") != NULL;
    if(!inside_flatpak) {
        if(access("/usr/bin/gsr-kms-server", F_OK) != 0) {
            fprintf(stderr, "gsr error: gsr_kms_client_init: /usr/bin/gsr-kms-server not found, please install gpu-screen-recorder first\n");
            return -1;
        }

        if(geteuid() == 0) {
            has_perm = true;
        } else {
            cap_t kms_server_cap = cap_get_file(server_filepath);
            if(kms_server_cap) {
                cap_flag_value_t res = 0;
                cap_get_flag(kms_server_cap, CAP_SYS_ADMIN, CAP_PERMITTED, &res);
                if(res == CAP_SET) {
                    //fprintf(stderr, "has permission!\n");
                    has_perm = true;
                } else {
                    //fprintf(stderr, "No permission:(\n");
                }
                cap_free(kms_server_cap);
            } else {
                if(errno == ENODATA)
                    fprintf(stderr, "gsr info: gsr_kms_client_init: gsr-kms-server is missing sys_admin cap and will require root authentication. To bypass this automatically, run: sudo setcap cap_sys_admin+ep '%s'\n", server_filepath);
                else
                    fprintf(stderr, "gsr info: gsr_kms_client_init: failed to get cap\n");
            }
        }
    }

    self->socket_fd = socket(AF_UNIX, SOCK_STREAM, 0);
    if(self->socket_fd == -1) {
        fprintf(stderr, "gsr error: gsr_kms_client_init: socket failed, error: %s\n", strerror(errno));
        goto err;
    }

    local_addr.sun_family = AF_UNIX;
    strncpy_safe(local_addr.sun_path, self->socket_path, sizeof(local_addr.sun_path));
    if(bind(self->socket_fd, (struct sockaddr*)&local_addr, sizeof(local_addr.sun_family) + strlen(local_addr.sun_path)) == -1) {
        fprintf(stderr, "gsr error: gsr_kms_client_init: failed to bind socket, error: %s\n", strerror(errno));
        goto err;
    }

    if(listen(self->socket_fd, 1) == -1) {
        fprintf(stderr, "gsr error: gsr_kms_client_init: failed to listen on socket, error: %s\n", strerror(errno));
        goto err;
    }

    pid_t pid = fork();
    if(pid == -1) {
        fprintf(stderr, "gsr error: gsr_kms_client_init: fork failed, error: %s\n", strerror(errno));
        goto err;
    } else if(pid == 0) { /* child */
        if(inside_flatpak) {
            const char *args[] = { "flatpak-spawn", "--host", "pkexec", "flatpak", "run", "--command=gsr-kms-server", "com.dec05eba.gpu_screen_recorder", self->socket_path, card_path, NULL };
            execvp(args[0], (char *const*)args);
        } else if(has_perm) {
            const char *args[] = { server_filepath, self->socket_path, card_path, NULL };
            execvp(args[0], (char *const*)args);
        } else {
            const char *args[] = { "pkexec", server_filepath, self->socket_path, card_path, NULL };
            execvp(args[0], (char *const*)args);
        }
        fprintf(stderr, "gsr error: gsr_kms_client_init: execvp failed, error: %s\n", strerror(errno));
        _exit(127);
    } else { /* parent */
        self->kms_server_pid = pid;
    }

    fprintf(stderr, "gsr info: gsr_kms_client_init: waiting for server to connect\n");
    for(;;) {
        struct timeval tv;
        fd_set rfds;
        FD_ZERO(&rfds);
        FD_SET(self->socket_fd, &rfds);

        tv.tv_sec = 0;
        tv.tv_usec = 100 * 1000; // 100 ms

        int select_res = select(1 + self->socket_fd, &rfds, NULL, NULL, &tv);
        if(select_res > 0) {
            socklen_t sock_len = 0;
            self->client_fd = accept(self->socket_fd, (struct sockaddr*)&remote_addr, &sock_len);
            if(self->client_fd == -1) {
                fprintf(stderr, "gsr error: gsr_kms_client_init: accept failed on socket, error: %s\n", strerror(errno));
                goto err;
            }
            break;
        } else {
            int status = 0;
            int wait_result = waitpid(self->kms_server_pid, &status, WNOHANG);
            if(wait_result != 0) {
                fprintf(stderr, "gsr error: gsr_kms_client_init: kms server died or never started, error: %s\n", strerror(errno));
                self->kms_server_pid = -1;
                goto err;
            } else if(WIFEXITED(status)) {
                int exit_code = WEXITSTATUS(status);
                fprintf(stderr, "gsr error: gsr_kms_client_init: kms server died or never started, exit code: %d\n", exit_code);
                self->kms_server_pid = -1;
                if(exit_code != 0)
                    result = exit_code;
                goto err;
            }
        }
    }
    fprintf(stderr, "gsr info: gsr_kms_client_init: server connected\n");

    return 0;

    err:
    gsr_kms_client_deinit(self);
    return result;
}

void gsr_kms_client_deinit(gsr_kms_client *self) {
    if(self->client_fd != -1) {
        close(self->client_fd);
        self->client_fd = -1;
    }

    if(self->socket_fd != -1) {
        close(self->socket_fd);
        self->socket_fd = -1;
    }

    if(self->kms_server_pid != -1) {
        kill(self->kms_server_pid, SIGINT);
        int status;
        waitpid(self->kms_server_pid, &status, 0);
        self->kms_server_pid = -1;
    }

    if(self->socket_path[0] != '\0') {
        remove(self->socket_path);
        self->socket_path[0] = '\0';
    }
}

int gsr_kms_client_get_kms(gsr_kms_client *self, gsr_kms_response *response) {
    response->result = KMS_RESULT_FAILED_TO_SEND;
    strcpy(response->err_msg, "failed to send");

    gsr_kms_request request;
    request.type = KMS_REQUEST_TYPE_GET_KMS;
    if(send_msg_to_server(self->client_fd, &request) == -1) {
        fprintf(stderr, "gsr error: gsr_kms_client_get_kms: failed to send request message to server\n");
        return -1;
    }

    const int recv_res = recv_msg_from_server(self->client_fd, response);
    if(recv_res == 0) {
        fprintf(stderr, "gsr warning: gsr_kms_client_get_kms: kms server shut down\n");
        return -1;
    } else if(recv_res == -1) {
        fprintf(stderr, "gsr error: gsr_kms_client_get_kms: failed to receive response\n");
        return -1;
    }

    return 0;
}