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authorEric Andersen2000-09-04 15:15:55 +0000
committerEric Andersen2000-09-04 15:15:55 +0000
commit9670083818467b01349e1df4ce97abc3c25b5a43 (patch)
treeeb2132593d8284699863129f0cc5c4e22a618565 /wget.c
parentb92223b6f5848b2cdb41c3a6b9261b47826a5816 (diff)
downloadbusybox-9670083818467b01349e1df4ce97abc3c25b5a43.zip
busybox-9670083818467b01349e1df4ce97abc3c25b5a43.tar.gz
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
Diffstat (limited to 'wget.c')
-rw-r--r--wget.c264
1 files changed, 264 insertions, 0 deletions
diff --git a/wget.c b/wget.c
new file mode 100644
index 0000000..4f894fc
--- /dev/null
+++ b/wget.c
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+/* 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:
+*/