callhandlerutil.cpp

#include "callhandlerutil.h"
#include "intercept.h"
#include "util.h"

#include <errno.h>
#include <sys/stat.h>

CallHandlerUtil::CallHandlerUtil(ICallHandler* next)
    : next(next), ctx({get_tls(), nullptr, nullptr, 0}) {};

int CallHandlerUtil::openat(int dirfd,
                            const char* path,
                            int flags,
                            mode_t mode) {
    if (!path) {
        return -EFAULT;
    }

    int ret = {0};
    CallOpen call;
    call.from_openat(&ret, dirfd, path, flags, mode);
    this->next->next(&ctx, &call);

    return ret;
};

int CallHandlerUtil::fstat(int fd, struct stat* statbuf) {
    if (!statbuf) {
        return -EFAULT;
    }

    int ret = {0};
    CallStat call;
    call.from_fstat(&ret, fd, statbuf);
    this->next->next(&ctx, &call);

    return ret;
}

int CallHandlerUtil::close(int fd) {
    int ret = {0};
    CallClose call;
    call.from_close(&ret, fd);
    this->next->next(&ctx, &call);

    return ret;
}

ssize_t CallHandlerUtil::read_file(char** out, const char* path) {
    ssize_t ret;
    ssize_t size;
    int fd;
    char* buf;
    struct stat st;

    *out = nullptr;

    ret = this->openat(AT_FDCWD, path, O_RDONLY, 0);
    if (ret < 0) {
        return ret;
    }
    fd = ret;

    ret = this->fstat(fd, &st);
    if (ret < 0) {
        this->close(fd);
        return ret;
    }
    if (!st.st_size) {
        this->close(fd);
        return 0;
    }
    size = st.st_size;

    buf = (char*)malloc(size);
    if (!buf) {
        this->close(fd);
        return -ENOMEM;
    }

    ret = read_full(fd, buf, size);
    this->close(fd);
    if (ret != size) {
        free(buf);
        return -EAGAIN;
    }

    *out = buf;
    return size;
}