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59f0d218 FF |
1 | // termux-api.c - helper binary for calling termux api classes |
2 | // Usage: termux-api ${API_METHOD} ${ADDITIONAL_FLAGS} | |
3 | // This executes | |
4 | // am broadcast com.termux.api/.TermuxApiReceiver --es socket_input ${INPUT_SOCKET} | |
5 | // --es socket_output ${OUTPUT_SOCKET} | |
6 | // --es ${API_METHOD} | |
7 | // ${ADDITIONAL_FLAGS} | |
8 | // where ${INPUT_SOCKET} and ${OUTPUT_SOCKET} are addresses to linux abstract namespace sockets, | |
9 | // used to pass on stdin to the java implementation and pass back output from java to stdout. | |
10 | #define _POSIX_SOURCE | |
11 | #define _GNU_SOURCE | |
12 | #include <fcntl.h> | |
13 | #include <pthread.h> | |
14 | #include <signal.h> | |
15 | #include <stdbool.h> | |
16 | #include <stdio.h> | |
17 | #include <stdlib.h> | |
18 | #include <string.h> | |
19 | #include <sys/socket.h> | |
20 | #include <sys/stat.h> | |
21 | #include <sys/types.h> | |
22 | #include <sys/un.h> | |
23 | #include <time.h> | |
24 | #include <unistd.h> | |
25 | ||
26 | // Function which execs "am broadcast ..". | |
b1a31654 | 27 | _Noreturn void exec_am_broadcast(int argc, char** argv, char* input_address_string, char* output_address_string) |
59f0d218 | 28 | { |
bb3266ca FF |
29 | // Redirect stdout to /dev/null (but leave stderr open): |
30 | close(STDOUT_FILENO); | |
31 | open("/dev/null", O_RDONLY); | |
32 | // Close stdin: | |
33 | close(STDIN_FILENO); | |
34 | ||
bb3266ca FF |
35 | int const extra_args = 15; // Including ending NULL. |
36 | char** child_argv = malloc((sizeof(char*)) * (argc + extra_args)); | |
37 | ||
38 | child_argv[0] = "am"; | |
39 | child_argv[1] = "broadcast"; | |
40 | child_argv[2] = "--user"; | |
b1a31654 | 41 | child_argv[3] = "0"; |
bb3266ca FF |
42 | child_argv[4] = "-n"; |
43 | child_argv[5] = "com.termux.api/.TermuxApiReceiver"; | |
44 | child_argv[6] = "--es"; | |
45 | // Input/output are reversed for the java process (our output is its input): | |
46 | child_argv[7] = "socket_input"; | |
47 | child_argv[8] = output_address_string; | |
48 | child_argv[9] = "--es"; | |
49 | child_argv[10] = "socket_output"; | |
50 | child_argv[11] = input_address_string; | |
51 | child_argv[12] = "--es"; | |
52 | child_argv[13] = "api_method"; | |
53 | child_argv[14] = argv[1]; | |
54 | ||
55 | // Copy the remaining arguments -2 for first binary and second api name: | |
56 | memcpy(child_argv + extra_args, argv + 2, (argc-1) * sizeof(char*)); | |
57 | ||
58 | // End with NULL: | |
59 | child_argv[argc + extra_args] = NULL; | |
60 | ||
61 | // Use an a executable taking care of PATH and LD_LIBRARY_PATH: | |
b1a31654 | 62 | execv("/data/data/com.termux/files/usr/bin/am", child_argv); |
bb3266ca | 63 | |
b1a31654 | 64 | perror("execv(\"/data/data/com.termux/files/usr/bin/am\")"); |
bb3266ca | 65 | exit(1); |
59f0d218 FF |
66 | } |
67 | ||
68 | void generate_uuid(char* str) { | |
b1a31654 FF |
69 | sprintf(str, "%x%x-%x-%x-%x-%x%x%x", |
70 | arc4random(), arc4random(), // Generates a 64-bit Hex number | |
71 | (uint32_t) getpid(), // Generates a 32-bit Hex number | |
72 | ((arc4random() & 0x0fff) | 0x4000), // Generates a 32-bit Hex number of the form 4xxx (4 indicates the UUID version) | |
73 | arc4random() % 0x3fff + 0x8000, // Generates a 32-bit Hex number in the range [0x8000, 0xbfff] | |
74 | arc4random(), arc4random(), arc4random()); // Generates a 96-bit Hex number | |
59f0d218 FF |
75 | } |
76 | ||
77 | // Thread function which reads from stdin and writes to socket. | |
78 | void* transmit_stdin_to_socket(void* arg) { | |
bb3266ca FF |
79 | int output_server_socket = *((int*) arg); |
80 | struct sockaddr_un remote_addr; | |
81 | socklen_t addrlen = sizeof(remote_addr); | |
82 | int output_client_socket = accept(output_server_socket, (struct sockaddr*) &remote_addr, &addrlen); | |
83 | ||
b1a31654 | 84 | ssize_t len; |
bb3266ca | 85 | char buffer[1024]; |
b1a31654 | 86 | while (len = read(STDIN_FILENO, &buffer, sizeof(buffer)), len > 0) { |
bb3266ca FF |
87 | if (write(output_client_socket, buffer, len) < 0) break; |
88 | } | |
89 | // Close output socket on end of input: | |
90 | close(output_client_socket); | |
91 | return NULL; | |
59f0d218 FF |
92 | } |
93 | ||
94 | // Main thread function which reads from input socket and writes to stdout. | |
95 | void transmit_socket_to_stdout(int input_socket_fd) { | |
b1a31654 | 96 | ssize_t len; |
bb3266ca | 97 | char buffer[1024]; |
b1a31654 | 98 | while ((len = read(input_socket_fd, &buffer, sizeof(buffer))) > 0) { |
bb3266ca FF |
99 | write(STDOUT_FILENO, buffer, len); |
100 | } | |
101 | if (len < 0) perror("read()"); | |
59f0d218 FF |
102 | } |
103 | ||
104 | int main(int argc, char** argv) { | |
bb3266ca FF |
105 | // Do not transform children into zombies when they terminate: |
106 | struct sigaction sigchld_action = { .sa_handler = SIG_DFL, .sa_flags = SA_RESTART | SA_NOCLDSTOP | SA_NOCLDWAIT }; | |
107 | sigaction(SIGCHLD, &sigchld_action, NULL); | |
108 | ||
109 | char input_address_string[100]; // This program reads from it. | |
110 | char output_address_string[100]; // This program writes to it. | |
111 | ||
bb3266ca FF |
112 | generate_uuid(input_address_string); |
113 | generate_uuid(output_address_string); | |
114 | ||
115 | struct sockaddr_un input_address = { .sun_family = AF_UNIX }; | |
116 | struct sockaddr_un output_address = { .sun_family = AF_UNIX }; | |
117 | // Leave struct sockaddr_un.sun_path[0] as 0 and use the UUID string as abstract linux namespace: | |
118 | strncpy(&input_address.sun_path[1], input_address_string, strlen(input_address_string)); | |
119 | strncpy(&output_address.sun_path[1], output_address_string, strlen(output_address_string)); | |
120 | ||
121 | int input_server_socket = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0); | |
122 | if (input_server_socket == -1) { perror("socket()"); return 1; } | |
123 | int output_server_socket = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0); | |
124 | if (output_server_socket == -1) { perror("socket()"); return 1; } | |
125 | ||
126 | if (bind(input_server_socket, (struct sockaddr*) &input_address, sizeof(sa_family_t) + strlen(input_address_string) + 1) == -1) { | |
127 | perror("bind(input)"); | |
128 | return 1; | |
129 | } | |
130 | if (bind(output_server_socket, (struct sockaddr*) &output_address, sizeof(sa_family_t) + strlen(output_address_string) + 1) == -1) { | |
131 | perror("bind(output)"); | |
132 | return 1; | |
133 | } | |
134 | ||
135 | if (listen(input_server_socket, 1) == -1) { perror("listen()"); return 1; } | |
136 | if (listen(output_server_socket, 1) == -1) { perror("listen()"); return 1; } | |
137 | ||
138 | pid_t fork_result = fork(); | |
139 | switch (fork_result) { | |
140 | case -1: perror("fork()"); return 1; | |
b1a31654 | 141 | case 0: exec_am_broadcast(argc, argv, input_address_string, output_address_string); |
bb3266ca FF |
142 | } |
143 | ||
144 | struct sockaddr_un remote_addr; | |
145 | socklen_t addrlen = sizeof(remote_addr); | |
146 | int input_client_socket = accept(input_server_socket, (struct sockaddr*) &remote_addr, &addrlen); | |
147 | ||
148 | pthread_t transmit_thread; | |
149 | pthread_create(&transmit_thread, NULL, transmit_stdin_to_socket, &output_server_socket); | |
150 | ||
151 | transmit_socket_to_stdout(input_client_socket); | |
152 | ||
153 | return 0; | |
59f0d218 FF |
154 | } |
155 |