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/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2018-2021 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <fcntl.h>
int main(int argc, char *argv[], char *envp[])
{
int fd, input = -1, pipes[2] = { 0 }, status;
pid_t compiler_pid;
char *output_path;
if (argc > 1 && argv[argc - 1][0] != '-') {
input = open(argv[1], O_RDONLY);
++argv;
--argc;
if (input < 0) {
perror("Error: unable to open input file");
return 1;
}
if (pipe(pipes) < 0) {
perror("Error: unable to open filter pipe");
return 1;
}
}
fd = memfd_create("cscript", 0);
if (fd < 0) {
perror("Error: unable to create memfd");
return 1;
}
if (asprintf(&output_path, "/proc/self/fd/%d", fd) < 0) {
perror("Error: unable to allocate memory for fd string");
return 1;
}
compiler_pid = fork();
if (compiler_pid < 0) {
perror("Error: unable to fork for compiler");
return 1;
}
if (compiler_pid == 0) {
const char *cc = getenv("CC") ?: "gcc";
close(input);
if (pipes[0] != 0) {
close(pipes[1]);
if (dup2(pipes[0], 0) < 0) {
perror("Error: unable to duplicate pipe fd");
_exit(1);
}
close(pipes[0]);
}
execlp(cc, cc, "-xc", "-o", output_path, "-", NULL);
_exit(1);
}
if (input != -1) {
char beginning[2];
ssize_t len;
close(pipes[0]);
len = read(input, beginning, 2);
if (len < 0) {
perror("Error: unable to read from input file");
return 1;
} else if (len == 2 && beginning[0] == '#' && beginning[1] == '!')
len = write(pipes[1], "//", 2);
else if (len > 0)
len = write(pipes[1], beginning, len);
if (len < 0) {
perror("Error: unable to write input preamble");
return 1;
}
if (splice(input, NULL, pipes[1], NULL, 0x7fffffff, 0) < 0) {
perror("Error: unable to splice input to compiler child");
return 1;
}
close(pipes[1]);
}
if (waitpid(compiler_pid, &status, 0) != compiler_pid || (!WIFEXITED(status) || WEXITSTATUS(status))) {
fprintf(stderr, "Error: compiler process did not complete successfully\n");
return 1;
}
if (fexecve(fd, argv, envp) < 0) {
perror("Error: could not execute compiled program");
return 1;
}
return 0;
}
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