Add fopen/close/rewind for urls

2 files changed, 510 insertions, 2 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 2cec940..c8377ff 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -3,8 +3,8 @@ include_directories(
 	${CMAKE_BINARY_DIR}/include
 )
 
-add_executable(spm spm.c config.c compat.c deps.c fs.c rpath.c find.c shell.c archive.c strings.c relocation.c install.c config_global.c manifest.c checksum.c)
-target_link_libraries(spm rt crypto ssl)
+add_executable(spm spm.c config.c compat.c deps.c fs.c rpath.c find.c shell.c archive.c strings.c relocation.c install.c config_global.c manifest.c checksum.c extern/url.c)
+target_link_libraries(spm rt crypto ssl curl)
 install(
 	TARGETS spm
 	DESTINATION ${CMAKE_INSTALL_PREFIX}/bin
diff --git a/src/extern/url.c b/src/extern/url.c
new file mode 100644
index 0000000..9cb9707
--- /dev/null
+++ b/src/extern/url.c
@@ -0,0 +1,508 @@
+/*****************************************************************************
+ *
+ * This example source code introduces a c library buffered I/O interface to
+ * URL reads it supports fopen(), fread(), fgets(), feof(), fclose(),
+ * rewind(). Supported functions have identical prototypes to their normal c
+ * lib namesakes and are preceaded by url_ .
+ *
+ * Using this code you can replace your program's fopen() with url_fopen()
+ * and fread() with url_fread() and it become possible to read remote streams
+ * instead of (only) local files. Local files (ie those that can be directly
+ * fopened) will drop back to using the underlying clib implementations
+ *
+ * See the main() function at the bottom that shows an app that retrieves from
+ * a specified url using fgets() and fread() and saves as two output files.
+ *
+ * Copyright (c) 2003 - 2019 Simtec Electronics
+ *
+ * Re-implemented by Vincent Sanders <vince@kyllikki.org> with extensive
+ * reference to original curl example code
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This example requires libcurl 7.9.7 or later.
+ */
+/* <DESC>
+ * implements an fopen() abstraction allowing reading from URLs
+ * </DESC>
+ */
+
+#include "url.h"
+
+/* we use a global one for convenience */
+static CURLM *multi_handle;
+
+/* curl calls this routine to get more data */
+static size_t write_callback(char *buffer,
+                             size_t size,
+                             size_t nitems,
+                             void *userp)
+{
+  char *newbuff;
+  size_t rembuff;
+
+  URL_FILE *url = (URL_FILE *)userp;
+  size *= nitems;
+
+  rembuff = url->buffer_len - url->buffer_pos; /* remaining space in buffer */
+
+  if(size > rembuff) {
+    /* not enough space in buffer */
+    newbuff = realloc(url->buffer, url->buffer_len + (size - rembuff));
+    if(newbuff == NULL) {
+      fprintf(stderr, "callback buffer grow failed\n");
+      size = rembuff;
+    }
+    else {
+      /* realloc succeeded increase buffer size*/
+      url->buffer_len += size - rembuff;
+      url->buffer = newbuff;
+    }
+  }
+
+  memcpy(&url->buffer[url->buffer_pos], buffer, size);
+  url->buffer_pos += size;
+
+  return size;
+}
+
+/* use to attempt to fill the read buffer up to requested number of bytes */
+static int fill_buffer(URL_FILE *file, size_t want)
+{
+  fd_set fdread;
+  fd_set fdwrite;
+  fd_set fdexcep;
+  struct timeval timeout;
+  int rc;
+  CURLMcode mc; /* curl_multi_fdset() return code */
+
+  /* only attempt to fill buffer if transactions still running and buffer
+   * doesn't exceed required size already
+   */
+  if((!file->still_running) || (file->buffer_pos > want))
+    return 0;
+
+  /* attempt to fill buffer */
+  do {
+    int maxfd = -1;
+    long curl_timeo = -1;
+
+    FD_ZERO(&fdread);
+    FD_ZERO(&fdwrite);
+    FD_ZERO(&fdexcep);
+
+    /* set a suitable timeout to fail on */
+    timeout.tv_sec = 60; /* 1 minute */
+    timeout.tv_usec = 0;
+
+    curl_multi_timeout(multi_handle, &curl_timeo);
+    if(curl_timeo >= 0) {
+      timeout.tv_sec = curl_timeo / 1000;
+      if(timeout.tv_sec > 1)
+        timeout.tv_sec = 1;
+      else
+        timeout.tv_usec = (curl_timeo % 1000) * 1000;
+    }
+
+    /* get file descriptors from the transfers */
+    mc = curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
+
+    if(mc != CURLM_OK) {
+      fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
+      break;
+    }
+
+    /* On success the value of maxfd is guaranteed to be >= -1. We call
+       select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
+       no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
+       to sleep 100ms, which is the minimum suggested value in the
+       curl_multi_fdset() doc. */
+
+    if(maxfd == -1) {
+#ifdef _WIN32
+      Sleep(100);
+      rc = 0;
+#else
+      /* Portable sleep for platforms other than Windows. */
+      struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
+      rc = select(0, NULL, NULL, NULL, &wait);
+#endif
+    }
+    else {
+      /* Note that on some platforms 'timeout' may be modified by select().
+         If you need access to the original value save a copy beforehand. */
+      rc = select(maxfd + 1, &fdread, &fdwrite, &fdexcep, &timeout);
+    }
+
+    switch(rc) {
+    case -1:
+      /* select error */
+      break;
+
+    case 0:
+    default:
+      /* timeout or readable/writable sockets */
+      curl_multi_perform(multi_handle, &file->still_running);
+      break;
+    }
+  } while(file->still_running && (file->buffer_pos < want));
+  return 1;
+}
+
+/* use to remove want bytes from the front of a files buffer */
+static int use_buffer(URL_FILE *file, size_t want)
+{
+  /* sort out buffer */
+  if(file->buffer_pos <= want) {
+    /* ditch buffer - write will recreate */
+    free(file->buffer);
+    file->buffer = NULL;
+    file->buffer_pos = 0;
+    file->buffer_len = 0;
+  }
+  else {
+    /* move rest down make it available for later */
+    memmove(file->buffer,
+            &file->buffer[want],
+            (file->buffer_pos - want));
+
+    file->buffer_pos -= want;
+  }
+  return 0;
+}
+
+URL_FILE *url_fopen(const char *url, const char *operation)
+{
+  /* this code could check for URLs or types in the 'url' and
+     basically use the real fopen() for standard files */
+
+  URL_FILE *file;
+  (void)operation;
+
+  file = calloc(1, sizeof(URL_FILE));
+  if(!file)
+    return NULL;
+
+  file->handle.file = fopen(url, operation);
+  if(file->handle.file)
+    file->type = CFTYPE_FILE; /* marked as URL */
+
+  else {
+    file->type = CFTYPE_CURL; /* marked as URL */
+    file->handle.curl = curl_easy_init();
+
+    curl_easy_setopt(file->handle.curl, CURLOPT_URL, url);
+    curl_easy_setopt(file->handle.curl, CURLOPT_WRITEDATA, file);
+    curl_easy_setopt(file->handle.curl, CURLOPT_VERBOSE, 0L);
+    curl_easy_setopt(file->handle.curl, CURLOPT_WRITEFUNCTION, write_callback);
+
+    if(!multi_handle)
+      multi_handle = curl_multi_init();
+
+    curl_multi_add_handle(multi_handle, file->handle.curl);
+
+    /* lets start the fetch */
+    curl_multi_perform(multi_handle, &file->still_running);
+
+    if((file->buffer_pos == 0) && (!file->still_running)) {
+      /* if still_running is 0 now, we should return NULL */
+
+      /* make sure the easy handle is not in the multi handle anymore */
+      curl_multi_remove_handle(multi_handle, file->handle.curl);
+
+      /* cleanup */
+      curl_easy_cleanup(file->handle.curl);
+
+      free(file);
+
+      file = NULL;
+    }
+  }
+  return file;
+}
+
+int url_fclose(URL_FILE *file)
+{
+  int ret = 0;/* default is good return */
+
+  switch(file->type) {
+  case CFTYPE_FILE:
+    ret = fclose(file->handle.file); /* passthrough */
+    break;
+
+  case CFTYPE_CURL:
+    /* make sure the easy handle is not in the multi handle anymore */
+    curl_multi_remove_handle(multi_handle, file->handle.curl);
+
+    /* cleanup */
+    curl_easy_cleanup(file->handle.curl);
+    break;
+
+  default: /* unknown or supported type - oh dear */
+    ret = EOF;
+    errno = EBADF;
+    break;
+  }
+
+  free(file->buffer);/* free any allocated buffer space */
+  free(file);
+
+  return ret;
+}
+
+int url_feof(URL_FILE *file)
+{
+  int ret = 0;
+
+  switch(file->type) {
+  case CFTYPE_FILE:
+    ret = feof(file->handle.file);
+    break;
+
+  case CFTYPE_CURL:
+    if((file->buffer_pos == 0) && (!file->still_running))
+      ret = 1;
+    break;
+
+  default: /* unknown or supported type - oh dear */
+    ret = -1;
+    errno = EBADF;
+    break;
+  }
+  return ret;
+}
+
+size_t url_fread(void *ptr, size_t size, size_t nmemb, URL_FILE *file)
+{
+  size_t want;
+
+  switch(file->type) {
+  case CFTYPE_FILE:
+    want = fread(ptr, size, nmemb, file->handle.file);
+    break;
+
+  case CFTYPE_CURL:
+    want = nmemb * size;
+
+    fill_buffer(file, want);
+
+    /* check if there's data in the buffer - if not fill_buffer()
+     * either errored or EOF */
+    if(!file->buffer_pos)
+      return 0;
+
+    /* ensure only available data is considered */
+    if(file->buffer_pos < want)
+      want = file->buffer_pos;
+
+    /* xfer data to caller */
+    memcpy(ptr, file->buffer, want);
+
+    use_buffer(file, want);
+
+    want = want / size;     /* number of items */
+    break;
+
+  default: /* unknown or supported type - oh dear */
+    want = 0;
+    errno = EBADF;
+    break;
+
+  }
+  return want;
+}
+
+char *url_fgets(char *ptr, size_t size, URL_FILE *file)
+{
+  size_t want = size - 1;/* always need to leave room for zero termination */
+  size_t loop;
+
+  switch(file->type) {
+  case CFTYPE_FILE:
+    ptr = fgets(ptr, (int)size, file->handle.file);
+    break;
+
+  case CFTYPE_CURL:
+    fill_buffer(file, want);
+
+    /* check if there's data in the buffer - if not fill either errored or
+     * EOF */
+    if(!file->buffer_pos)
+      return NULL;
+
+    /* ensure only available data is considered */
+    if(file->buffer_pos < want)
+      want = file->buffer_pos;
+
+    /*buffer contains data */
+    /* look for newline or eof */
+    for(loop = 0; loop < want; loop++) {
+      if(file->buffer[loop] == '\n') {
+        want = loop + 1;/* include newline */
+        break;
+      }
+    }
+
+    /* xfer data to caller */
+    memcpy(ptr, file->buffer, want);
+    ptr[want] = 0;/* always null terminate */
+
+    use_buffer(file, want);
+
+    break;
+
+  default: /* unknown or supported type - oh dear */
+    ptr = NULL;
+    errno = EBADF;
+    break;
+  }
+
+  return ptr;/*success */
+}
+
+void url_rewind(URL_FILE *file)
+{
+  switch(file->type) {
+  case CFTYPE_FILE:
+    rewind(file->handle.file); /* passthrough */
+    break;
+
+  case CFTYPE_CURL:
+    /* halt transaction */
+    curl_multi_remove_handle(multi_handle, file->handle.curl);
+
+    /* restart */
+    curl_multi_add_handle(multi_handle, file->handle.curl);
+
+    /* ditch buffer - write will recreate - resets stream pos*/
+    free(file->buffer);
+    file->buffer = NULL;
+    file->buffer_pos = 0;
+    file->buffer_len = 0;
+
+    break;
+
+  default: /* unknown or supported type - oh dear */
+    break;
+  }
+}
+
+#define FGETSFILE "fgets.test"
+#define FREADFILE "fread.test"
+#define REWINDFILE "rewind.test"
+
+/* Small main program to retrieve from a url using fgets and fread saving the
+ * output to two test files (note the fgets method will corrupt binary files if
+ * they contain 0 chars */
+int _test_url_fopen(int argc, char *argv[])
+{
+  URL_FILE *handle;
+  FILE *outf;
+
+  size_t nread;
+  char buffer[256];
+  const char *url;
+
+  if(argc < 2)
+    url = "http://192.168.7.3/testfile";/* default to testurl */
+  else
+    url = argv[1];/* use passed url */
+
+  /* copy from url line by line with fgets */
+  outf = fopen(FGETSFILE, "wb+");
+  if(!outf) {
+    perror("couldn't open fgets output file\n");
+    return 1;
+  }
+
+  handle = url_fopen(url, "r");
+  if(!handle) {
+    printf("couldn't url_fopen() %s\n", url);
+    fclose(outf);
+    return 2;
+  }
+
+  while(!url_feof(handle)) {
+    url_fgets(buffer, sizeof(buffer), handle);
+    fwrite(buffer, 1, strlen(buffer), outf);
+  }
+
+  url_fclose(handle);
+
+  fclose(outf);
+
+
+  /* Copy from url with fread */
+  outf = fopen(FREADFILE, "wb+");
+  if(!outf) {
+    perror("couldn't open fread output file\n");
+    return 1;
+  }
+
+  handle = url_fopen("testfile", "r");
+  if(!handle) {
+    printf("couldn't url_fopen() testfile\n");
+    fclose(outf);
+    return 2;
+  }
+
+  do {
+    nread = url_fread(buffer, 1, sizeof(buffer), handle);
+    fwrite(buffer, 1, nread, outf);
+  } while(nread);
+
+  url_fclose(handle);
+
+  fclose(outf);
+
+
+  /* Test rewind */
+  outf = fopen(REWINDFILE, "wb+");
+  if(!outf) {
+    perror("couldn't open fread output file\n");
+    return 1;
+  }
+
+  handle = url_fopen("testfile", "r");
+  if(!handle) {
+    printf("couldn't url_fopen() testfile\n");
+    fclose(outf);
+    return 2;
+  }
+
+  nread = url_fread(buffer, 1, sizeof(buffer), handle);
+  fwrite(buffer, 1, nread, outf);
+  url_rewind(handle);
+
+  buffer[0]='\n';
+  fwrite(buffer, 1, 1, outf);
+
+  nread = url_fread(buffer, 1, sizeof(buffer), handle);
+  fwrite(buffer, 1, nread, outf);
+
+  url_fclose(handle);
+
+  fclose(outf);
+
+  return 0;/* all done */
+}