Initial implementation of wget, from Chip Rosenthal <chip@laserlink.net>.

Very cool.  Still lacks "chunked" transfer-coding, so not totally RFC
compliant for HTTP1.1, but very nice nonethe less, and very small.
 -Erik

1 files changed, 264 insertions, 0 deletions

diff --git a/networking/wget.c b/networking/wget.c
new file mode 100644
index 000000000..4f894fcaa
--- /dev/null
+++ b/networking/wget.c
@@ -0,0 +1,264 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * wget - retrieve a file using HTTP
+ *
+ * Chip Rosenthal
+ * Covad Communications
+ * <chip@laserlink.net>
+ */
+
+#include "internal.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+
+void parse_url(char *url, char **uri_host, int *uri_port, char **uri_path);
+FILE *open_socket(char *host, int port);
+char *gethdr(char *buf, size_t bufsiz, FILE *fp, int *istrunc);
+
+
+int wget_main(int argc, char **argv)
+{
+        FILE *sfp;                                      /* socket to web server                         */
+        char *uri_host, *uri_path;      /* parsed from command line url         */
+        int uri_port;
+        char *s, buf[512];
+        int n;
+
+        char *fname_out = NULL;         /* where to direct output (-O)          */
+        int do_continue = 0;            /* continue a prev transfer (-c)        */
+        long beg_range = 0L;            /*   range at which continue begins     */
+        int got_clen = 0;                       /* got content-length: from server      */
+        long clen = 1L;                         /*   the content length                         */
+
+        /*
+         * Crack command line.
+         */
+        while ((n = getopt(argc, argv, "cO:")) != EOF) {
+                switch (n) {
+                case 'c':
+                        ++do_continue;
+                        break;
+                case 'O':
+                        fname_out = optarg;
+                        break;
+                default:
+                        usage(wget_usage);
+                }
+        }
+        if (do_continue && !fname_out)
+                fatalError("wget: cannot specify continue (-c) without a filename (-O)\n");
+        if (argc - optind != 1)
+                        usage(wget_usage);
+        /*
+         * Parse url into components.
+         */
+        parse_url(argv[optind], &uri_host, &uri_port, &uri_path);
+
+        /*
+         * Open socket to server.
+         */
+        sfp = open_socket(uri_host, uri_port);
+
+        /*
+         * Open the output stream.
+         */
+        if (fname_out != NULL) {
+                /* Check if the file is supposed to go to stdout */
+                if (!strcmp(fname_out, "-") == 0) {
+                        /* Nope -- so open the output file */
+                        if (freopen(fname_out, (do_continue ? "a" : "w"), stdout) == NULL)
+                                fatalError("wget: freopen(%s): %s\n", fname_out, strerror(errno));
+                }
+        }
+
+        /*
+         * Determine where to start transfer.
+         */
+        if (do_continue) {
+                struct stat sbuf;
+                if (fstat(fileno(stdout), &sbuf) < 0)
+                        fatalError("wget: fstat(): %s\n", strerror(errno));
+                if (sbuf.st_size > 0)
+                        beg_range = sbuf.st_size;
+                else
+                        do_continue = 0;
+        }
+
+        /*
+         * Send HTTP request.
+         */
+        fprintf(sfp, "GET %s HTTP/1.1\r\nHost: %s\r\n", uri_path, uri_host);
+        if (do_continue)
+                fprintf(sfp, "Range: bytes=%ld-\r\n", beg_range);
+        fputs("Connection: close\r\n\r\n", sfp);
+
+        /*
+         * Retrieve HTTP response line and check for "200" status code.
+         */
+        if (fgets(buf, sizeof(buf), sfp) == NULL)
+                fatalError("wget: no response from server\n");
+        for (s = buf ; *s != '\0' && !isspace(*s) ; ++s)
+                ;
+        for ( ; isspace(*s) ; ++s)
+                ;
+        switch (atoi(s)) {
+        case 200:
+                if (!do_continue)
+                        break;
+                fatalError("wget: cannot continue - server does not properly support ranges\n");
+        case 206:
+                if (do_continue)
+                        break;
+                /*FALLTHRU*/
+        default:
+                fatalError("wget: server returned error: %s", buf);
+        }
+
+        /*
+         * Retrieve HTTP headers.
+         */
+        while ((s = gethdr(buf, sizeof(buf), sfp, &n)) != NULL) {
+                if (strcmp(buf, "content-length") == 0) {
+                        clen = atol(s);
+                        got_clen = 1;
+                        continue;
+                }
+                if (strcmp(buf, "transfer-encoding") == 0) {
+                        fatalError("wget: i do not do transfer encodings, server wants to do: %s\n", s);
+                        continue;
+                }
+        }
+
+        /*
+         * Retrieve HTTP body.
+         */
+        while (clen > 0 && (n = fread(buf, 1, sizeof(buf), sfp)) > 0) {
+                fwrite(buf, 1, n, stdout);
+                if (got_clen)
+                        clen -= n;
+        }
+        if (n == 0 && ferror(sfp))
+                fatalError("wget: network read error: %s", strerror(errno));
+
+        exit(0);
+}
+
+
+void parse_url(char *url, char **uri_host, int *uri_port, char **uri_path)
+{
+        char *s, *h;
+
+        *uri_port = 80;
+
+        if (strncmp(url, "http://", 7) != 0)
+                fatalError("wget: not an http url: %s\n", url);
+
+        /* pull the host portion to the front of the buffer */
+        for (s = url, h = url+7 ; *h != '/' ; ++h) {
+                if (*h == '\0')
+                        fatalError("wget: cannot parse url: %s\n", url);
+                if (*h == ':') {
+                        *uri_port = atoi(h+1);
+                        *h = '\0';
+                }
+                *s++ = *h;
+        }
+        *s = '\0';
+        *uri_host = url;
+        *uri_path = h;
+}
+
+
+FILE *open_socket(char *host, int port)
+{
+        struct sockaddr_in sin;
+        struct hostent *hp;
+        int fd;
+        FILE *fp;
+
+        memzero(&sin, sizeof(sin));
+        sin.sin_family = AF_INET;
+        if ((hp = (struct hostent *) gethostbyname(host)) == NULL)
+                fatalError("wget: cannot resolve %s\n", host);
+        memcpy(&sin.sin_addr, hp->h_addr_list[0], hp->h_length);
+        sin.sin_port = htons(port);
+
+        /*
+         * Get the server onto a stdio stream.
+         */
+        if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+                fatalError("wget: socket(): %s\n", strerror(errno));
+        if (connect(fd, (struct sockaddr *) &sin, sizeof(sin)) < 0)
+                fatalError("wget: connect(%s): %s\n", host, strerror(errno));
+        if ((fp = fdopen(fd, "r+")) == NULL)
+                fatalError("wget: fdopen(): %s\n", strerror(errno));
+
+        return fp;
+}
+
+
+char *gethdr(char *buf, size_t bufsiz, FILE *fp, int *istrunc)
+{
+        char *s, *hdrval;
+        int c;
+
+        *istrunc = 0;
+
+        /* retrieve header line */
+        if (fgets(buf, bufsiz, fp) == NULL)
+                return NULL;
+
+        /* see if we are at the end of the headers */
+        for (s = buf ; *s == '\r' ; ++s)
+                ;
+        if (s[0] == '\n')
+                return NULL;
+
+        /* convert the header name to lower case */
+        for (s = buf ; isalnum(*s) || *s == '-' ; ++s)
+                *s = tolower(*s);
+
+        /* verify we are at the end of the header name */
+        if (*s != ':')
+                fatalError("wget: bad header line: %s\n", buf);
+
+        /* locate the start of the header value */
+        for (*s++ = '\0' ; *s == ' ' || *s == '\t' ; ++s)
+                ;
+        hdrval = s;
+
+        /* locate the end of header */
+        while (*s != '\0' && *s != '\r' && *s != '\n')
+                ++s;
+
+        /* end of header found */
+        if (*s != '\0') {
+                *s = '\0';
+                return hdrval;
+        }
+
+        /* Rat!  The buffer isn't big enough to hold the entire header value. */
+        while (c = getc(fp), c != EOF && c != '\n')
+                ;
+        *istrunc = 1;
+        return hdrval;
+}
+
+/*
+Local Variables:
+c-file-style: "linux"
+c-basic-offset: 4
+tab-width: 4
+End:
+*/