mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-12-24 22:53:42 +00:00
80 lines
2.3 KiB
C
80 lines
2.3 KiB
C
// This is a tiny wrapper that converts the extra arv[0] argument
|
|
// from binfmt-misc with the P flag enabled to QEMU parameters.
|
|
// It also prevents LD_* environment variables from being applied
|
|
// to QEMU itself.
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
|
|
#ifndef TARGET_QEMU
|
|
#error "Define TARGET_QEMU to be the path to the qemu-user binary (e.g., -DTARGET_QEMU=\"/full/path/to/qemu-riscv64\")"
|
|
#endif
|
|
|
|
extern char **environ;
|
|
|
|
int main(int argc, char *argv[]) {
|
|
if (argc < 3) {
|
|
fprintf(stderr, "%s: This should be run as the binfmt interpreter with the P flag\n", argv[0]);
|
|
fprintf(stderr, "%s: My preconfigured qemu-user binary: %s\n", argv[0], TARGET_QEMU);
|
|
return 1;
|
|
}
|
|
|
|
size_t environ_count = 0;
|
|
for (char **cur = environ; *cur != NULL; ++cur) {
|
|
environ_count++;
|
|
}
|
|
|
|
size_t new_argc = 3;
|
|
size_t new_argv_alloc = argc + 2 * environ_count + 2; // [ "-E", env ] for each LD_* env + [ "-0", argv0 ]
|
|
char **new_argv = (char**)malloc((new_argv_alloc + 1) * sizeof(char*));
|
|
if (!new_argv) {
|
|
fprintf(stderr, "FATAL: Failed to allocate new argv array\n");
|
|
abort();
|
|
}
|
|
|
|
new_argv[0] = TARGET_QEMU;
|
|
new_argv[1] = "-0";
|
|
new_argv[2] = argv[2];
|
|
|
|
// Pass all LD_ env variables as -E and strip them in `new_environ`
|
|
size_t new_environc = 0;
|
|
char **new_environ = (char**)malloc((environ_count + 1) * sizeof(char*));
|
|
if (!new_environ) {
|
|
fprintf(stderr, "FATAL: Failed to allocate new environ array\n");
|
|
abort();
|
|
}
|
|
|
|
for (char **cur = environ; *cur != NULL; ++cur) {
|
|
if (strncmp("LD_", *cur, 3) == 0) {
|
|
new_argv[new_argc++] = "-E";
|
|
new_argv[new_argc++] = *cur;
|
|
} else {
|
|
new_environ[new_environc++] = *cur;
|
|
}
|
|
}
|
|
new_environ[new_environc] = NULL;
|
|
|
|
size_t new_arg_start = new_argc;
|
|
new_argc += argc - 3 + 2; // [ "--", full_binary_path ]
|
|
|
|
if (argc > 3) {
|
|
memcpy(&new_argv[new_arg_start + 2], &argv[3], (argc - 3) * sizeof(char**));
|
|
}
|
|
|
|
new_argv[new_arg_start] = "--";
|
|
new_argv[new_arg_start + 1] = argv[1];
|
|
new_argv[new_argc] = NULL;
|
|
|
|
#ifdef DEBUG
|
|
for (size_t i = 0; i < new_argc; ++i) {
|
|
fprintf(stderr, "argv[%zu] = %s\n", i, new_argv[i]);
|
|
}
|
|
#endif
|
|
|
|
return execve(new_argv[0], new_argv, new_environ);
|
|
}
|
|
|
|
// vim: et:ts=4:sw=4
|