httpd: optional support for partial downloads

diff --git a/networking/Config.in b/networking/Config.in
index d687dbe..030b1c0 100644 (file)
--- a/networking/Config.in
+++ b/networking/Config.in
@@ -83,6 +83,15 @@ config HTTPD
        help
          Serve web pages via an HTTP server.
 
+config FEATURE_HTTPD_RANGES
+       bool "Support 'Ranges:' header"
+       default n
+       depends on HTTPD
+       help
+         Makes httpd emit "Accept-Ranges: bytes" header and understand
+         "Range: bytes=NNN-[MMM]" header. Allows for resuming interrupted
+         downloads, seeking in multimedia players etc.
+
 config FEATURE_HTTPD_USE_SENDFILE
        bool "Use sendfile system call"
        default n

diff --git a/networking/httpd.c b/networking/httpd.c
index a8e5df9..0574160 100644 (file)
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -138,6 +138,7 @@ typedef struct Htaccess_IP {
 
 enum {
        HTTP_OK = 200,
+       HTTP_PARTIAL_CONTENT = 206,
        HTTP_MOVED_TEMPORARILY = 302,
        HTTP_BAD_REQUEST = 400,       /* malformed syntax */
        HTTP_UNAUTHORIZED = 401, /* authentication needed, respond with auth hdr */
@@ -165,6 +166,9 @@ enum {
 
 static const uint16_t http_response_type[] ALIGN2 = {
        HTTP_OK,
+#if ENABLE_FEATURE_HTTPD_RANGES
+       HTTP_PARTIAL_CONTENT,
+#endif
        HTTP_MOVED_TEMPORARILY,
        HTTP_REQUEST_TIMEOUT,
        HTTP_NOT_IMPLEMENTED,
@@ -192,7 +196,10 @@ static const struct {
        const char *info;
 } http_response[ARRAY_SIZE(http_response_type)] = {
        { "OK", NULL },
-       { "Found", "Directories must end with a slash" }, /* ?? */
+#if ENABLE_FEATURE_HTTPD_RANGES
+       { "Partial Content", NULL },
+#endif
+       { "Found", NULL },
        { "Request Timeout", "No request appeared within 60 seconds" },
        { "Not Implemented", "The requested method is not recognized" },
 #if ENABLE_FEATURE_HTTPD_BASIC_AUTH
@@ -214,13 +221,13 @@ static const struct {
 #endif
 };
 
+
 struct globals {
        int verbose;            /* must be int (used by getopt32) */
        smallint flg_deny_all;
 
        unsigned rmt_ip;        /* used for IP-based allow/deny rules */
        time_t last_mod;
-       off_t ContentLength;    /* -1 - unknown */
        char *rmt_ip_str;       /* for $REMOTE_ADDR and $REMOTE_PORT */
        const char *bind_addr_or_port;
 
@@ -237,6 +244,13 @@ struct globals {
        USE_FEATURE_HTTPD_CGI(char *referer;)
        USE_FEATURE_HTTPD_CGI(char *user_agent;)
 
+       off_t file_size;        /* -1 - unknown */
+#if ENABLE_FEATURE_HTTPD_RANGES
+       off_t range_start;
+       off_t range_end;
+       off_t range_len;
+#endif
+
 #if ENABLE_FEATURE_HTTPD_BASIC_AUTH
        Htaccess *g_auth;       /* config user:password lines */
 #endif
@@ -264,13 +278,18 @@ struct globals {
 #define home_httpd        (G.home_httpd       )
 #define found_mime_type   (G.found_mime_type  )
 #define found_moved_temporarily (G.found_moved_temporarily)
-#define ContentLength     (G.ContentLength    )
 #define last_mod          (G.last_mod         )
 #define ip_a_d            (G.ip_a_d           )
 #define g_realm           (G.g_realm          )
 #define remoteuser        (G.remoteuser       )
 #define referer           (G.referer          )
 #define user_agent        (G.user_agent       )
+#define file_size         (G.file_size        )
+#if ENABLE_FEATURE_HTTPD_RANGES
+#define range_start       (G.range_start      )
+#define range_end         (G.range_end        )
+#define range_len         (G.range_len        )
+#endif
 #define rmt_ip_str        (G.rmt_ip_str       )
 #define g_auth            (G.g_auth           )
 #define mime_a            (G.mime_a           )
@@ -283,9 +302,17 @@ struct globals {
        PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
        USE_FEATURE_HTTPD_BASIC_AUTH(g_realm = "Web Server Authentication";) \
        bind_addr_or_port = "80"; \
-       ContentLength = -1; \
+       file_size = -1; \
 } while (0)
 
+#if !ENABLE_FEATURE_HTTPD_RANGES
+enum {
+       range_start = 0,
+       range_end = MAXINT(off_t) - 1,
+       range_len = MAXINT(off_t),
+};
+#endif
+
 
 #define STRNCASECMP(a, str) strncasecmp((a), (str), sizeof(str)-1)
 
@@ -921,10 +948,26 @@ static void send_headers(int responseNum)
        }
 #endif
 
-       if (ContentLength != -1) {    /* file */
+       if (file_size != -1) {    /* file */
                strftime(tmp_str, sizeof(tmp_str), RFC1123FMT, gmtime(&last_mod));
-               len += sprintf(iobuf + len, "Last-Modified: %s\r\n%s %"OFF_FMT"d\r\n",
-                       tmp_str, "Content-length:", ContentLength);
+#if ENABLE_FEATURE_HTTPD_RANGES
+               if (responseNum == HTTP_PARTIAL_CONTENT) {
+                       len += sprintf(iobuf + len, "Content-Range: bytes %"OFF_FMT"d-%"OFF_FMT"d/%"OFF_FMT"d\r\n",
+                                       range_start,
+                                       range_end,
+                                       file_size);
+                       file_size = range_end - range_start + 1;
+               }
+#endif
+               len += sprintf(iobuf + len,
+#if ENABLE_FEATURE_HTTPD_RANGES
+                       "Accept-Ranges: bytes\r\n"
+#endif
+                       "Last-Modified: %s\r\n%s %"OFF_FMT"d\r\n",
+                               tmp_str,
+                               "Content-length:",
+                               file_size
+               );
        }
        iobuf[len++] = '\r';
        iobuf[len++] = '\n';
@@ -1373,7 +1416,7 @@ static void send_file_and_exit(const char *url, int headers)
        const char *try_suffix;
        ssize_t count;
 #if ENABLE_FEATURE_HTTPD_USE_SENDFILE
-       off_t offset = 0;
+       off_t offset;
 #endif
 
        suffix = strrchr(url, '.');
@@ -1415,6 +1458,26 @@ static void send_file_and_exit(const char *url, int headers)
                if (headers)
                        send_headers_and_exit(HTTP_NOT_FOUND);
        }
+#if ENABLE_FEATURE_HTTPD_RANGES
+       if (!headers)
+               range_start = 0; /* err pages and ranges don't mix */
+       range_len = MAXINT(off_t);
+       if (range_start) {
+               if (!range_end) {
+                       range_end = file_size - 1;
+               }
+               if (range_end < range_start
+                || lseek(f, range_start, SEEK_SET) != range_start
+               ) {
+                       lseek(f, 0, SEEK_SET);
+                       range_start = 0;
+               } else {
+                       range_len = range_end - range_start + 1;
+                       send_headers(HTTP_PARTIAL_CONTENT);
+                       headers = 0;
+               }
+       }
+#endif
 
        if (headers)
                send_headers(HTTP_OK);
@@ -1424,24 +1487,32 @@ static void send_file_and_exit(const char *url, int headers)
        signal(SIGPIPE, SIG_IGN);
 
 #if ENABLE_FEATURE_HTTPD_USE_SENDFILE
+       offset = range_start;
        do {
-               /* byte count (3rd arg) is rounded down to 64k */
-               count = sendfile(1, f, &offset, MAXINT(ssize_t) - 0xffff);
+               /* sz is rounded down to 64k */
+               ssize_t sz = MAXINT(ssize_t) - 0xffff;
+               USE_FEATURE_HTTPD_RANGES(if (sz > range_len) sz = range_len;)
+               count = sendfile(1, f, &offset, sz);
                if (count < 0) {
-                       if (offset == 0)
+                       if (offset == range_start)
                                goto fallback;
                        goto fin;
                }
-       } while (count > 0);
+               USE_FEATURE_HTTPD_RANGES(range_len -= sz;)
+       } while (count > 0 && range_len);
        log_and_exit();
 
  fallback:
 #endif
        while ((count = safe_read(f, iobuf, IOBUF_SIZE)) > 0) {
-               ssize_t n = count;
-               count = full_write(1, iobuf, count);
+               ssize_t n;
+               USE_FEATURE_HTTPD_RANGES(if (count > range_len) count = range_len;)
+               n = full_write(1, iobuf, count);
                if (count != n)
                        break;
+               USE_FEATURE_HTTPD_RANGES(range_len -= count;)
+               if (!range_len)
+                       break;
        }
 #if ENABLE_FEATURE_HTTPD_USE_SENDFILE
  fin:
@@ -1781,6 +1852,23 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
                                credentials = checkPerm(urlcopy, tptr);
                        }
 #endif          /* FEATURE_HTTPD_BASIC_AUTH */
+#if ENABLE_FEATURE_HTTPD_RANGES
+                       if (STRNCASECMP(iobuf, "Range:") == 0) {
+                               // We know only bytes=NNN-[MMM]
+                               char *s = skip_whitespace(iobuf + sizeof("Range:")-1);
+                               if (strncmp(s, "bytes=", 6) == 0) {
+                                       s += sizeof("bytes=")-1;
+                                       range_start = BB_STRTOOFF(s, &s, 10);
+                                       if (s[0] != '-' || range_start < 0) {
+                                               range_start = 0;
+                                       } else if (s[1]) {
+                                               range_end = BB_STRTOOFF(s+1, NULL, 10);
+                                               if (errno || range_end < range_start)
+                                                       range_start = 0;
+                                       }
+                               }
+                       }
+#endif
                } /* while extra header reading */
        }
 
@@ -1833,8 +1921,7 @@ static void handle_incoming_and_exit(const len_and_sockaddr *fromAddr)
        if (urlp[-1] == '/')
                strcpy(urlp, "index.html");
        if (stat(tptr, &sb) == 0) {
-               /* It's a dir URL and there is index.html */
-               ContentLength = sb.st_size;
+               file_size = sb.st_size;
                last_mod = sb.st_mtime;
        }
 #if ENABLE_FEATURE_HTTPD_CGI

diff --git a/shell/ash.c b/shell/ash.c
index 167232c..4924741 100644 (file)
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -2494,6 +2494,7 @@ pwdcmd(int argc, char **argv)
 #define DQSYNTAX   1    /* in double quotes */
 #define SQSYNTAX   2    /* in single quotes */
 #define ARISYNTAX  3    /* in arithmetic */
+#define PSSYNTAX   4    /* prompt */
 
 #if ENABLE_ASH_OPTIMIZE_FOR_SIZE
 #define USE_SIT_FUNCTION
@@ -9886,6 +9887,9 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
        smallint dblquote;
        smallint oldstyle;
        smallint prevsyntax; /* syntax before arithmetic */
+#if ENABLE_ASH_EXPAND_PRMT
+       smallint pssyntax;   /* we are expanding a prompt string */
+#endif
        int varnest;         /* levels of variables expansion */
        int arinest;         /* levels of arithmetic expansion */
        int parenlevel;      /* levels of parens in arithmetic */
@@ -9910,6 +9914,11 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
        dblquote = (syntax == DQSYNTAX);
        oldstyle = 0;
        prevsyntax = 0;
+#if ENABLE_ASH_EXPAND_PRMT
+       pssyntax = (syntax == PSSYNTAX);
+       if (pssyntax)
+               syntax = DQSYNTAX;
+#endif
        varnest = 0;
        arinest = 0;
        parenlevel = 0;
@@ -9948,6 +9957,12 @@ readtoken1(int firstc, int syntax, char *eofmark, int striptabs)
                                        if (doprompt)
                                                setprompt(2);
                                } else {
+#if ENABLE_ASH_EXPAND_PRMT
+                                       if (c == '$' && pssyntax) {
+                                               USTPUTC(CTLESC, out);
+                                               USTPUTC('\\', out);
+                                       }
+#endif
                                        if (dblquote &&
                                                c != '\\' && c != '`' &&
                                                c != '$' && (
@@ -10780,7 +10795,7 @@ expandstr(const char *ps)
 
        /* XXX Fix (char *) cast. */
        setinputstring((char *)ps);
-       readtoken1(pgetc(), DQSYNTAX, nullstr, 0);
+       readtoken1(pgetc(), PSSYNTAX, nullstr, 0);
        popfile();
 
        n.narg.type = NARG;