paivana

pipeline_client.c (9538B)

---

 /*
   This file is part of Paivana.
   Copyright (C) 2026 Taler Systems SA
 
   Paivana is free software; you can redistribute it and/or
   modify it under the terms of the GNU Affero General Public License
   as published by the Free Software Foundation; either version
   3, or (at your option) any later version.
 
   Paivana is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU Affero General Public License for more details.
 
   You should have received a copy of the GNU Affero General Public
   License along with Paivana; see the file COPYING.  If not,
   write to the Free Software Foundation, Inc., 51 Franklin
   Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
 
 /**
  * @file pipeline_client.c
  * @brief HTTP/1.1 pipelining client: opens a single TCP connection
  *        to a host/port, sends N GET requests back-to-back *without*
  *        waiting for their responses, then reads N responses in
  *        order and prints each body (separated by "---").
  *
  * Used by the paivana test suite to verify that paivana correctly
  * handles pipelined requests on a single keep-alive connection.
  */
 #include <arpa/inet.h>
 #include <errno.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #define BUF_GROW 8192
 
 static int
 connect_to (const char *host,
             const char *port)
 {
   struct addrinfo hints = { 0 };
   struct addrinfo *res = NULL;
   int rc;
 
   hints.ai_family = AF_UNSPEC;
   hints.ai_socktype = SOCK_STREAM;
   rc = getaddrinfo (host,
                     port,
                     &hints,
                     &res);
   if (0 != rc)
   {
     fprintf (stderr,
              "getaddrinfo(%s:%s): %s\n",
              host,
              port,
              gai_strerror (rc));
     return -1;
   }
   for (struct addrinfo *p = res; NULL != p; p = p->ai_next)
   {
     int fd = socket (p->ai_family,
                      p->ai_socktype,
                      p->ai_protocol);
     if (fd < 0)
       continue;
     if (0 == connect (fd,
                       p->ai_addr,
                       p->ai_addrlen))
     {
       freeaddrinfo (res);
       return fd;
     }
     close (fd);
   }
   freeaddrinfo (res);
   fprintf (stderr,
            "could not connect to %s:%s\n",
            host,
            port);
   return -1;
 }
 
 
 static int
 write_all (int fd,
            const char *buf,
            size_t len)
 {
   while (len > 0)
   {
     ssize_t w = write (fd,
                        buf,
                        len);
 
     if (w < 0)
     {
       if (EINTR == errno)
         continue;
       return -1;
     }
     buf += w;
     len -= (size_t) w;
   }
   return 0;
 }
 
 
 /**
  * Read exactly @a want bytes from @a fd into the tail of the buffer.
  * Grows the buffer as needed.  @a have is updated.
  */
 static int
 ensure_bytes (int fd,
               char **buf,
               size_t *cap,
               size_t *have,
               size_t want)
 {
   while (*have < want)
   {
     ssize_t r;
     if (*have + BUF_GROW > *cap)
     {
       size_t nc = *cap ? *cap * 2 : BUF_GROW;
       char *nb;
 
       while (nc < *have + BUF_GROW)
         nc *= 2;
       nb = realloc (*buf,
                     nc);
       if (NULL == nb)
         return -1;
       *buf = nb;
       *cap = nc;
     }
 
     r = read (fd,
               *buf + *have,
               *cap - *have);
     if (r < 0)
     {
       if (EINTR == errno)
         continue;
       return -1;
     }
     if (0 == r)
       return -1; /* EOF */
     *have += (size_t) r;
   }
   return 0;
 }
 
 
 /**
  * Find the end of the HTTP header block ("\r\n\r\n") starting at
  * some offset in buf.  Returns the absolute offset of the byte
  * just past the final "\r\n\r\n", or (size_t) -1 if not yet present.
  * Grows the buffer / reads more data as needed.
  */
 static size_t
 read_headers (int fd,
               char **buf,
               size_t *cap,
               size_t *have,
               size_t start)
 {
   /* First offset not yet examined.  Carried across the read loop:
      restarting the scan at @a start after every read would be
      quadratic in the size of the header block. */
   size_t scan = start;
 
   while (1)
   {
     while (scan + 3 < *have)
     {
       if ( ('\r' == (*buf)[scan]) &&
            ('\n' == (*buf)[scan + 1]) &&
            ('\r' == (*buf)[scan + 2]) &&
            ('\n' == (*buf)[scan + 3]) )
         return scan + 4;
       scan++;
     }
     if (ensure_bytes (fd,
                       buf,
                       cap,
                       have,
                       *have + 1))
       return (size_t) -1;
   }
 }
 
 
 /**
  * Extract Content-Length from a header block [start, hdr_end).
  * Returns -1 if not found.
  */
 static long long
 header_content_length (const char *buf,
                        size_t start,
                        size_t hdr_end)
 {
   const char *hdrs = buf + start;
   size_t len = hdr_end - start;
   const char *p = hdrs;
   const char *end = hdrs + len;
   const char *needle = "Content-Length:";
 
   while (p + strlen (needle) < end)
   {
     const char *line_end = memchr (p,
                                    '\n',
                                    end - p);
 
     if (NULL == line_end)
       break;
     if (0 == strncasecmp (p,
                           needle,
                           strlen (needle)))
     {
       const char *v = p + strlen (needle);
 
       while ( (v < line_end) &&
               (' ' == *v ||
                '\t' == *v) )
         v++;
       return strtoll (v,
                       NULL,
                       10);
     }
     p = line_end + 1;
   }
   return -1;
 }
 
 
 /**
  * Parse the status code out of "HTTP/1.1 <code> ..."
  */
 static int
 header_status (const char *buf,
                size_t start,
                size_t hdr_end)
 {
   const char *p = buf + start;
   const char *sp = memchr (p,
                            ' ',
                            hdr_end - start);
 
   if (NULL == sp)
     return -1;
   return atoi (sp + 1);
 }
 
 
 int
 main (int argc, char **argv)
 {
   const char *host;
   const char *port;
   int n_paths;
   int fd;
 
   /* Before argc is checked: with argc == 1, argv[2] is a read one
      past the end of the argument vector. */
   if (argc < 4)
   {
     fprintf (stderr,
              "usage: %s <host> <port> <path> [<path>...]\n",
              argv[0]);
     return 2;
   }
   host = argv[1];
   port = argv[2];
   n_paths = argc - 3;
 
   fd = connect_to (host,
                    port);
   if (fd < 0)
     return 1;
 
   /* Pipeline: send all requests back-to-back. */
   for (int i = 0; i < n_paths; i++)
   {
     char req[2048];
     const char *conn_hdr
       = (i == n_paths - 1)
       ? "close"
       : "keep-alive";
     int n = snprintf (req,
                       sizeof (req),
                       "GET %s HTTP/1.1\r\n"
                       "Host: %s:%s\r\n"
                       "User-Agent: paivana-pipeline-test\r\n"
                       "Connection: %s\r\n"
                       "\r\n",
                       argv[3 + i],
                       host,
                       port,
                       conn_hdr);
     if ( (n < 0) ||
          ((size_t) n >= sizeof (req)) )
     {
       fprintf (stderr,
                "request too long\n");
       close (fd);
       return 1;
     }
     if (0 != write_all (fd,
                         req,
                         (size_t) n))
     {
       fprintf (stderr,
                "write failed: %s\n",
                strerror (errno));
       close (fd);
       return 1;
     }
   }
 
   {
     /* Now read N responses in order, using Content-Length. */
     char *buf = NULL;
     size_t cap = 0;
     size_t have = 0;
     size_t pos = 0;
     int ret = 0;
 
     for (int i = 0; i < n_paths; i++)
     {
       size_t hdr_end = read_headers (fd,
                                      &buf,
                                      &cap,
                                      &have,
                                      pos);
       long status;
       long long cl;
       size_t body_end;
 
       if ((size_t) -1 == hdr_end)
       {
         fprintf (stderr,
                  "failed to read headers of response #%d\n",
                  i);
         ret = 1;
         break;
       }
       status = header_status (buf,
                               pos,
                               hdr_end);
       cl = header_content_length (buf,
                                   pos,
                                   hdr_end);
       if (cl < 0)
       {
         fprintf (stderr,
                  "response #%d has no Content-Length (got status %d); "
                  "cannot safely parse pipelined response stream\n",
                  i,
                  (int) status);
         ret = 1;
         break;
       }
 
       body_end = hdr_end + (size_t) cl;
       if (0 != ensure_bytes (fd,
                              &buf,
                              &cap,
                              &have,
                              body_end))
       {
         fprintf (stderr,
                  "short body for response #%d (expected %lld bytes)\n",
                  i, cl);
         ret = 1;
         break;
       }
       printf ("--- response %d: status=%d len=%lld ---\n",
               i,
               (int) status,
               cl);
       fwrite (buf + hdr_end,
               1,
               (size_t) cl,
               stdout);
       if ( (cl > 0) &&
            (buf[body_end - 1] != '\n') )
         putchar ('\n');
       pos = body_end;
     }
     free (buf);
     close (fd);
     return ret;
   }
 }