utils: xtgettcap: new utility, to send XTGETTCAP queries

utils/meson.build

@@ -0,0 +1 @@
+executable('xtgettcap', 'xtgettcap.c')

utils/xtgettcap.c

@@ -0,0 +1,175 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <termios.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <poll.h>
+#include <ctype.h>
+#include <assert.h>
+
+static struct termios orig_termios;
+
+static void
+disable_raw_mode(void)
+{
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios) < 0)
+        exit(__LINE__);
+}
+
+static void
+enable_raw_mode(void)
+{
+    if (tcgetattr(STDIN_FILENO, &orig_termios) < 0)
+        exit(__LINE__);
+
+    atexit(disable_raw_mode);
+
+    struct termios raw = orig_termios;
+    raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+    raw.c_oflag &= ~(OPOST);
+    raw.c_cflag |= (CS8);
+    raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
+    raw.c_cc[VMIN] = 0;
+    raw.c_cc[VTIME] = 1;
+
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) < 0)
+        exit(__LINE__);
+}
+
+static const char *
+hexlify(const char *s)
+{
+    static char buf[1024];
+
+    const size_t len = strlen(s);
+    for (size_t i = 0; i < len; i++)
+        sprintf(&buf[i * 2], "%02x", s[i]);
+    buf[len * 2 + 1] = '\0';
+
+    return buf;
+}
+
+static size_t
+unhexlify(char *dst, const char *src)
+{
+    size_t count = 0;
+    for (const char *p = src; *p != '\0'; p += 2, dst++, count++)
+        sscanf(p, "%02hhx", (unsigned char *)dst);
+
+    *dst = '\0';
+    return count;
+}
+
+int
+main(int argc, const char *const *argv)
+{
+    enable_raw_mode();
+
+    const size_t query_count = argc - 1;
+
+    printf("\x1bP+q");
+    for (int i = 1; i < argc; i++)
+        printf("%s%s", i > 1 ? ";" : "", hexlify(argv[i]));
+    printf("\033\\");
+
+    fflush(NULL);
+
+    size_t replies = 0;
+    while (replies < query_count) {
+        struct pollfd fds[] = {{.fd = STDIN_FILENO, .events = POLLIN}};
+        int r = poll(fds, sizeof(fds) / sizeof(fds[0]), -1);
+        if (r < 0)
+            exit(__LINE__);
+
+        char buf[1024] = {0};
+        ssize_t count = read(STDIN_FILENO, buf, sizeof(buf));
+
+        if (count < 0)
+            exit(__LINE__);
+
+        if (count == 1 && buf[0] == 'q')
+            break;
+
+        printf("reply: (%zd chars): ", count);
+
+        for (size_t i = 0; i < (size_t)count; i++) {
+            if (isprint(buf[i]))
+                printf("%c", buf[i]);
+            else if (buf[i] == '\033')
+                printf("\033[1;31m\\E\033[m");
+            else
+                printf("%02x", (uint8_t)buf[i]);
+        }
+        printf("\r\n");
+
+        const char *p = buf;
+        const char *end = buf + count;
+
+        while (p < end) {
+
+            const char *ST = strstr(p, "\033\\");
+            if (ST == NULL)
+                break;
+
+            if (count < 5 ||
+                (strncmp(p, "\033P1+r", 5) != 00 &&
+                 strncmp(p, "\033P0+r", 5) != 0))
+            {
+                break;
+            }
+
+            const bool success = p[2] == '1';
+
+            char decoded[1024];
+            char copy[ST - &p[5] + 1];
+            strncpy(copy, &p[5], ST - &p[5]);
+            copy[ST - &p[5]] = '\0';
+
+            char *saveptr = NULL;
+            for (char *key_value = strtok_r(copy, "; ", &saveptr);
+                 key_value != NULL;
+                 key_value = strtok_r(NULL, "; ", &saveptr))
+            {
+                // printf("key-value=%s\n", key_value);
+                const char *key = strtok(key_value, "=");
+                const char *value = strtok(NULL, "=");
+
+#if 0
+                assert((success && value != NULL) ||
+                       (!success && value == NULL));
+#endif
+
+                //printf("key=%s, value=%s\n", key, value);
+                size_t len = unhexlify(decoded, key);
+
+                if (value != NULL) {
+                    decoded[len++] = '=';
+                    len += unhexlify(&decoded[len], value);
+                }
+
+                const int color = success ? 39 : 31;
+
+                printf("  \033[%dm", color);
+                for (size_t i = 0 ; i < len; i++) {
+                    if (isprint(decoded[i]))
+                        printf("%c", decoded[i]);
+                    else if (decoded[i] == '\033')
+                        printf("\033[1;31m\\E\033[22;%dm", color);
+                    else
+                        printf("\033[1m%02x\033[22m", (uint8_t)decoded[i]);
+                }
+                printf("\033[m\r\n");
+                replies++;
+            }
+
+            p = ST + 2;
+        }
+
+    }
+
+    return 0;
+}