ccryp/password.c at master · vukamecos/ccryp · GitHub

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#ifndef _WIN32
#define _POSIX_C_SOURCE 200809L
#endif
#include "password.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef _WIN32

#include <windows.h>

uint8_t *read_password(const char *prompt, size_t *out_len) {
    /* Open the console directly so piped stdin doesn't interfere. */
    HANDLE h = CreateFileA("CONIN$",
                           GENERIC_READ | GENERIC_WRITE,
                           FILE_SHARE_READ | FILE_SHARE_WRITE,
                           NULL, OPEN_EXISTING, 0, NULL);
    if (h == INVALID_HANDLE_VALUE) {
        fprintf(stderr, "error: cannot open console\n");
        return NULL;
    }

    DWORD old_mode;
    GetConsoleMode(h, &old_mode);
    SetConsoleMode(h, old_mode & ~ENABLE_ECHO_INPUT);

    fprintf(stderr, "%s", prompt);
    fflush(stderr);

    size_t cap = 256;
    char *buf = malloc(cap);
    if (!buf) {
        SetConsoleMode(h, old_mode);
        CloseHandle(h);
        fprintf(stderr, "\nerror: out of memory\n");
        return NULL;
    }

    size_t pos = 0;
    char c;
    DWORD n_read;
    while (ReadFile(h, &c, 1, &n_read, NULL) && n_read == 1) {
        if (c == '\r' || c == '\n') break;
        if (pos + 1 >= cap) {
            size_t new_cap = cap * 2;
            char *new_buf = realloc(buf, new_cap);
            if (!new_buf) {
                memset(buf, 0, cap);
                free(buf);
                SetConsoleMode(h, old_mode);
                CloseHandle(h);
                fprintf(stderr, "\nerror: out of memory\n");
                return NULL;
            }
            buf = new_buf;
            cap = new_cap;
        }
        buf[pos++] = c;
    }
    fprintf(stderr, "\n");

    SetConsoleMode(h, old_mode);
    CloseHandle(h);

    if (pos == 0) {
        memset(buf, 0, cap);
        free(buf);
        fprintf(stderr, "error: password cannot be empty\n");
        return NULL;
    }

    *out_len = pos;
    return (uint8_t *)buf;
}

#else

#include <termios.h>
#include <unistd.h>
#include <fcntl.h>

uint8_t *read_password(const char *prompt, size_t *out_len) {
    int fd;
    int need_close = 0;

    if (isatty(STDIN_FILENO)) {
        fd = STDIN_FILENO;
    } else {
        fd = open("/dev/tty", O_RDWR);
        if (fd < 0) {
            fprintf(stderr, "error: cannot open /dev/tty\n");
            return NULL;
        }
        need_close = 1;
    }

    struct termios old_tc, new_tc;
    if (tcgetattr(fd, &old_tc) != 0) {
        fprintf(stderr, "error: tcgetattr failed\n");
        if (need_close) close(fd);
        return NULL;
    }
    new_tc = old_tc;
    new_tc.c_lflag &= ~(tcflag_t)ECHO;
    if (tcsetattr(fd, TCSAFLUSH, &new_tc) != 0) {
        fprintf(stderr, "error: cannot disable echo\n");
        if (need_close) close(fd);
        return NULL;
    }

    fprintf(stderr, "%s", prompt);

    size_t cap = 256;
    char *buf = malloc(cap);
    if (!buf) {
        tcsetattr(fd, TCSAFLUSH, &old_tc);
        if (need_close) close(fd);
        fprintf(stderr, "\nerror: out of memory\n");
        return NULL;
    }

    size_t pos = 0;
    char c;
    while (1) {
        ssize_t n = read(fd, &c, 1);
        if (n <= 0 || c == '\n' || c == '\r')
            break;
        if (pos + 1 >= cap) {
            size_t new_cap = cap * 2;
            char *new_buf = realloc(buf, new_cap);
            if (!new_buf) {
                memset(buf, 0, cap);
                free(buf);
                tcsetattr(fd, TCSAFLUSH, &old_tc);
                if (need_close) close(fd);
                fprintf(stderr, "\nerror: out of memory\n");
                return NULL;
            }
            buf = new_buf;
            cap = new_cap;
        }
        buf[pos++] = c;
    }
    fprintf(stderr, "\n");

    tcsetattr(fd, TCSAFLUSH, &old_tc);
    if (need_close)
        close(fd);

    if (pos == 0) {
        memset(buf, 0, cap);
        free(buf);
        fprintf(stderr, "error: password cannot be empty\n");
        return NULL;
    }

    *out_len = pos;
    return (uint8_t *)buf;
}

#endif