1 // termux-api.c - helper binary for calling termux api classes
2 // Usage: termux-api ${API_METHOD} ${ADDITIONAL_FLAGS}
4 // am broadcast com.termux.api/.TermuxApiReceiver --es socket_input ${INPUT_SOCKET}
5 // --es socket_output ${OUTPUT_SOCKET}
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.
19 #include <sys/socket.h>
21 #include <sys/types.h>
26 // Function which execs "am broadcast ..".
27 _Noreturn
void exec_am_broadcast(int argc
, char** argv
, char* input_address_string
, char* output_address_string
)
29 // Redirect stdout to /dev/null (but leave stderr open):
31 open("/dev/null", O_RDONLY
);
35 int const extra_args
= 15; // Including ending NULL.
36 char** child_argv
= malloc((sizeof(char*)) * (argc
+ extra_args
));
39 child_argv
[1] = "broadcast";
40 child_argv
[2] = "--user";
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];
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*));
59 child_argv
[argc
+ extra_args
] = NULL
;
61 // Use an a executable taking care of PATH and LD_LIBRARY_PATH:
62 execv("/data/data/com.termux/files/usr/bin/am", child_argv
);
64 perror("execv(\"/data/data/com.termux/files/usr/bin/am\")");
68 void generate_uuid(char* str
) {
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
77 // Thread function which reads from stdin and writes to socket.
78 void* transmit_stdin_to_socket(void* arg
) {
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
);
86 while (len
= read(STDIN_FILENO
, &buffer
, sizeof(buffer
)), len
> 0) {
87 if (write(output_client_socket
, buffer
, len
) < 0) break;
89 // Close output socket on end of input:
90 close(output_client_socket
);
94 // Main thread function which reads from input socket and writes to stdout.
95 void transmit_socket_to_stdout(int input_socket_fd
) {
98 while ((len
= read(input_socket_fd
, &buffer
, sizeof(buffer
))) > 0) {
99 write(STDOUT_FILENO
, buffer
, len
);
101 if (len
< 0) perror("read()");
104 int main(int argc
, char** argv
) {
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
);
109 char input_address_string
[100]; // This program reads from it.
110 char output_address_string
[100]; // This program writes to it.
112 generate_uuid(input_address_string
);
113 generate_uuid(output_address_string
);
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
));
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; }
126 if (bind(input_server_socket
, (struct sockaddr
*) &input_address
, sizeof(sa_family_t
) + strlen(input_address_string
) + 1) == -1) {
127 perror("bind(input)");
130 if (bind(output_server_socket
, (struct sockaddr
*) &output_address
, sizeof(sa_family_t
) + strlen(output_address_string
) + 1) == -1) {
131 perror("bind(output)");
135 if (listen(input_server_socket
, 1) == -1) { perror("listen()"); return 1; }
136 if (listen(output_server_socket
, 1) == -1) { perror("listen()"); return 1; }
138 pid_t fork_result
= fork();
139 switch (fork_result
) {
140 case -1: perror("fork()"); return 1;
141 case 0: exec_am_broadcast(argc
, argv
, input_address_string
, output_address_string
);
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
);
148 pthread_t transmit_thread
;
149 pthread_create(&transmit_thread
, NULL
, transmit_stdin_to_socket
, &output_server_socket
);
151 transmit_socket_to_stdout(input_client_socket
);