exec process within a macOS download quarantine context

quarantine-exec.c

#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

enum qtn_flags {
    QTN_FLAG_DOWNLOAD = 0x0001,
};

typedef struct _qtn_proc *qtn_proc_t;

#define qtn_proc_alloc _qtn_proc_alloc
qtn_proc_t qtn_proc_alloc(void);

#define qtn_proc_apply_to_self _qtn_proc_apply_to_self
int qtn_proc_apply_to_self(qtn_proc_t);

#define qtn_proc_free _qtn_proc_free
void qtn_proc_free(qtn_proc_t);

#define qtn_proc_init _qtn_proc_init
void qtn_proc_init(qtn_proc_t);

#define qtn_proc_init_with_self _qtn_proc_init_with_self
int qtn_proc_init_with_self(qtn_proc_t);

#define qtn_proc_set_flags _qtn_proc_set_flags
int qtn_proc_set_flags(qtn_proc_t, uint32_t);

#define qtn_proc_set_identifier _qtn_proc_set_identifier
int qtn_proc_set_identifier(qtn_proc_t, const char *);

int quarantine(void) {
    int ret = 0;

    qtn_proc_t proc = qtn_proc_alloc();
    if (!proc) {
        ret = errno;

        goto EXIT;
    }

    if (qtn_proc_init_with_self(proc)) {
        qtn_proc_init(proc);
    }

    char *bundle_identifier = getenv("__CFBundleIdentifier");
    if (bundle_identifier) {
        if ((ret = qtn_proc_set_identifier(proc, bundle_identifier))) {
            goto FAIL;
        }
    }

    if ((ret = qtn_proc_set_flags(proc, QTN_FLAG_DOWNLOAD))) {
        goto FAIL;
    }

    if ((ret = qtn_proc_apply_to_self(proc))) {
        goto FAIL;
    }

FAIL:
    qtn_proc_free(proc);

EXIT:
    return ret;
}

int main(int argc, char *argv[]) {
    int ret = 0;

    if (argc < 2) {
        ret = -1;

        printf("usage: %s file [argv ...]\n", argv[0]);
        goto EXIT;
    }

    if ((ret = quarantine())) {
        perror("quarantine");
        return ret;
    }

    char **args = malloc(argc * sizeof(char *));
    for (size_t i = 0; i < argc - 1; ++i) {
        args[i] = argv[i + 1];
    }
    args[argc - 1] = NULL;

    if ((ret = execvp(argv[1], args))) {
        perror("execvp");
        goto EXIT;
    }

EXIT:
    return ret;
}