tal/grab_file: new module

[ccan] / ccan / tal / grab_file / grab_file.c

diff --git a/ccan/tal/grab_file/grab_file.c b/ccan/tal/grab_file/grab_file.c
new file mode 100644 (file)
index 0000000..88e7c22
--- /dev/null
+++ b/ccan/tal/grab_file/grab_file.c
@@ -0,0 +1,64 @@
+/* Licensed under LGPLv2+ - see LICENSE file for details */
+#include "grab_file.h"
+#include <ccan/tal/tal.h>
+#include <ccan/noerr/noerr.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+void *grab_fd(const void *ctx, int fd)
+{
+       int ret;
+       size_t max, size;
+       char *buffer;
+       struct stat st;
+
+       size = 0;
+
+       if (fstat(fd, &st) == 0 && S_ISREG(st.st_mode))
+               max = st.st_size;
+       else
+               max = 16384;
+
+       buffer = tal_arr(ctx, char, max+1);
+       while ((ret = read(fd, buffer + size, max - size)) > 0) {
+               size += ret;
+               if (size == max) {
+                       size_t extra = max;
+                       if (extra > 1024 * 1024)
+                               extra = 1024 * 1024;
+
+                       if (!tal_resize(&buffer, max+extra+1))
+                               return NULL;
+
+                       max += extra;
+               }
+       }
+       if (ret < 0)
+               buffer = tal_free(buffer);
+       else {
+               buffer[size] = '\0';
+               tal_resize(&buffer, size+1);
+       }
+
+       return buffer;
+}
+
+void *grab_file(const void *ctx, const char *filename)
+{
+       int fd;
+       char *buffer;
+
+       if (!filename)
+               fd = dup(STDIN_FILENO);
+       else
+               fd = open(filename, O_RDONLY, 0);
+
+       if (fd < 0)
+               return NULL;
+
+       buffer = grab_fd(ctx, fd);
+       close_noerr(fd);
+       return buffer;
+}