Add basic function to process attachment

src/fmail.c

@@ -24,10 +24,12 @@
 #include <stdlib.h>
 #include <getopt.h>
 #include <locale.h>
+#include <string.h>
 #include <ctype.h>
 #include <time.h>
 
 #include <gpgme.h>
+#include <magic.h>
 
 #include <sbuffer.h>
 #include <xmem.h>
@@ -80,16 +82,17 @@ See the COPYING file or <http://www.gnu.org/licenses/gpl.html>.\n\
 
 /* Helper functions. */
 
+const char base64_chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                            "abcdefghijklmnopqrstuvwxyz"
+                            "0123456789+/";
+
 static char *
 generate_boundary(char *buffer, size_t len)
 {
-    static const char chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-                                "abcdefghijklmnopqrstuvwxyz"
-                                "0123456789+/";
     int i;
 
     for ( i = 0; i < len - 1; i++ )
-        buffer[i] = chars[rand() % (sizeof(chars) - 1)];
+        buffer[i] = base64_chars[rand() % (sizeof(base64_chars) - 1)];
     buffer[i] = '\0';
 
     return buffer;
@@ -143,6 +146,35 @@ qp_encode_stream(FILE *in, FILE *out)
     }
 }
 
+static void
+base64_encode_stream(FILE *in, FILE *out)
+{
+    unsigned char buffer[3];
+    int n, j;
+
+    j = 0;
+    while ( (n = fread(buffer, 1, 3, in)) > 0 ) {
+        char quartet[4];
+
+        if ( n < 3 )
+            buffer[2] = 0;
+        if ( n < 2 )
+            buffer[1] = 0;
+
+        quartet[0] = base64_chars[buffer[0] >> 2];
+        quartet[1] = base64_chars[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xf0) >> 4)];
+        quartet[2] = (unsigned char) (n > 1 ? base64_chars[((buffer[1] & 0x0f) << 2) | ((buffer[2] & 0x0c) >> 6)] : '=' );
+        quartet[3] = (unsigned char) (n > 2 ? base64_chars[buffer[2] & 0x3f] : '=');
+
+        j += 1;
+        fwrite(quartet, 1, 4, out);
+        if ( j == 16 ) {
+            fprintf(out, "\r\n");
+            j = 0;
+        }
+    }
+}
+
 static char *
 rfc2822_date(void)
 {
@@ -269,6 +301,49 @@ sign_stream(gpgme_ctx_t ctx, FILE *in, FILE *out)
 
 
 
+/* Attachments stuff. */
+
+static magic_t
+initialize_magic(void)
+{
+    magic_t ctx;
+
+    if ( ! (ctx = magic_open(MAGIC_SYMLINK | MAGIC_MIME)) )
+        err(EXIT_FAILURE, "cannot obtain libmagic cookie");
+
+    if ( magic_load(ctx, NULL) == -1 )
+        err(EXIT_FAILURE, "cannot load default magic database");
+
+    return ctx;
+}
+
+static void
+process_attachment(const char *filename, magic_t ctx, FILE *out)
+{
+    const char *mime, *last_eq;
+    int binary;
+    FILE *f;
+
+    mime = magic_file(ctx, filename);
+    last_eq = strrchr(mime, '=');
+    binary = strcmp(last_eq, "=binary") ? 0 : 1;
+
+    fprintf(out, "Content-Type: %s\r\n", mime);
+    fprintf(out, "Content-Transfer-Encoding: %s\r\n", binary ? "base64" : "quoted-printable");
+    fprintf(out, "Content-Disposition: attachment; filename=%s\r\n\r\n", filename);
+
+    f = fopen(filename, "r");
+    if ( binary )
+        base64_encode_stream(f, out);
+    else
+        qp_encode_stream(f, out);
+    fclose(f);
+
+    fprintf(out, "\r\n");
+}
+
+
+
 /* Main function. */
 
 int
@@ -277,6 +352,7 @@ main(int argc, char *argv[])
     char c, **attachments;
     string_buffer_t *headers;
     gpgme_ctx_t sign_ctx;
+    magic_t mgc_ctx;
     int att_count;
 
     struct option options[] = {
@@ -293,6 +369,7 @@ main(int argc, char *argv[])
 
     headers = sb_new(0);
     sign_ctx = NULL;
+    mgc_ctx = initialize_magic();
     attachments = NULL;
     att_count = 0;
 
@@ -349,5 +426,7 @@ main(int argc, char *argv[])
     if ( attachments )
         free(attachments);
 
+    magic_close(mgc_ctx);
+
     return EXIT_SUCCESS;
 }