miniroon

commit 570ad8dc58ee32d83fc1108a08ad23cf6876ef38
parent f29bb200c1fb86697c4bbda34fbd96c21c169767
Author: Jan Pobrislo <ccx@te2000.cz>
Date:   Tue, 30 Jul 2024 18:18:15 +0000

Add WIP miniroon implementation.

Diffstat:
A
src/miniroon.c
 | 
134
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 134 insertions(+), 0 deletions(-)
diff --git a/src/miniroon.c b/src/miniroon.c
@@ -0,0 +1,134 @@
+#include <errno.h>
+#include <unistd.h>
+#include <sys/select.h>
+
+#include <skalibs/types.h>
+#include <skalibs/strerr.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/exec.h>
+#include <skalibs/netstring.h>
+#include <skalibs/uint64.h>
+
+#define USAGE "macrun directory"
+#define PROG "macrun"
+
+#define input_fd 0
+#define payload_size_max 1024*1024
+
+typedef struct {
+  char *data;
+  size_t len;
+} bytebuffer_t;
+
+int netstring_get_chunk (const bytebuffer_t *input, bytebuffer_t *chunk, bytebuffer_t *rest)
+{
+  uint64_t nlen;  /* size of payload */
+  size_t pos;  /* size of numerical prefix */
+  if (!input->len) {
+    return 0;
+  }
+  pos = uint64_scan(input->start, &nlen) ;
+  if (pos >= input->len) {
+    return 0;
+  }
+  if (input->start[pos] != ':') {
+    return 0;
+  }
+  char const *s = input->start + pos + 1;  /* start of payload */
+  if (len <= nlen + pos + 1) {
+    return 0;
+  }
+  if (s[nlen] != ',') {
+    return 0;
+  }
+  if (chunk != NULL) {
+    chunk->data = s;
+    chunk->len = nlen;
+  }
+  if (rest != NULL) {
+    chunk->data = s + 1;
+    chunk->len = input->len - nlen - pos - 2;
+  }
+  return 1;
+}
+
+void fd_block(int fd) {
+    int flags = fcntl(fd, F_GETFL);
+    if(flags == -1) {
+        strerr_dief1sys(111, "fcntl() getfd");
+    }
+    if(fcntl(fd, F_SETFL, flags | O_NONBLOCK) < 0) {
+        strerr_dief1sys(111, "fcntl() setfd");
+    }
+}
+
+int handle_payload(size_t payload_size) {
+  char payload[payload_size+1];
+  char *read_next = payload;
+  ssize_t read_size;
+  while(read_next - payload < payload_size + 1) {
+    read_size = read(input_fd, read_next, payload_size + 1 - (read_next - payload));
+    if(read_size == 0) {
+      strerr_dief1x(111, "EOF before full netstring payload was read");
+    }
+    if(read_size == -1) {
+      if(errno != EINTR) {
+        strerr_dief1sys(111, "read()");
+      }
+      continue;
+    }
+    read_next += read_size;
+  }
+  if(payload[payload_size] != ',') {
+      strerr_dief1x(111, "Invalid netstring terminator");
+  }
+
+  bytebuffer_t input, chunk, next;
+  next.data = payload;
+  next.len = payload_size;
+
+  while(next.len) {
+    input = next;
+    if(!netstring_get_chunk(&input, &chunk, &next)) {
+      strerr_dief1x(111, "Malformed netstring");
+    }
+
+  }
+}
+
+int main (int argc, char const *const *argv)
+{
+  char read_char;
+  size_t payload_size = 0;
+
+  fd_block(input_fd);
+
+  while(payload_size < payload_size_max) {
+    switch(read(input_fd, &read_char, 1)) {
+    case 0:
+      strerr_dief1x(111, "EOF before netstring size was read");
+      break;
+    case 1:
+      if(read_char == ':') {
+	return handle_payload(payload_size);
+      } else if(size_next >= '0' && size_next <= '9') {
+	payload_size *= 10;
+	payload_size += read_char - '0';
+      } else {
+	strerr_dief1x(111, "Malformed netstring on input");
+      }
+      break;
+    }
+    case -1:
+      if(errno != EINTR) {
+        strerr_dief1sys(111, "read()");
+      }
+      break;
+    default:
+      strerr_dief1x(110, "Unexpected return value from read()");
+      break;
+  }
+
+  strerr_dief1x(111, "Input netstring too big");
+  return 111;
+}