/* Handling of recursive HTTP retrieving. Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc. This file is part of Wget. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #ifdef HAVE_STRING_H # include #else # include #endif /* HAVE_STRING_H */ #ifdef HAVE_UNISTD_H # include #endif /* HAVE_UNISTD_H */ #include #include #include #include #include "wget.h" #include "url.h" #include "recur.h" #include "utils.h" #include "retr.h" #include "ftp.h" #include "fnmatch.h" #include "host.h" extern char *version_string; #define ROBOTS_FILENAME "robots.txt" /* #### Many of these lists should really be hashtables! */ /* List of downloaded URLs. */ static urlpos *urls_downloaded; /* List of HTML URLs. */ static slist *urls_html; /* List of undesirable-to-load URLs. */ static slist *ulist; /* List of forbidden locations. */ static char **forbidden = NULL; /* Current recursion depth. */ static int depth; /* Base directory we're recursing from (used by no_parent). */ static char *base_dir; /* The host name for which we last checked robots. */ static char *robots_host; static int first_time = 1; /* Construct the robots URL. */ static struct urlinfo *robots_url PARAMS ((const char *, const char *)); static uerr_t retrieve_robots PARAMS ((const char *, const char *)); static char **parse_robots PARAMS ((const char *)); static int robots_match PARAMS ((struct urlinfo *, char **)); /* Cleanup the data structures associated with recursive retrieving (the variables above). */ void recursive_cleanup (void) { free_slist (ulist); ulist = NULL; free_vec (forbidden); forbidden = NULL; free_slist (urls_html); urls_html = NULL; free_urlpos (urls_downloaded); urls_downloaded = NULL; FREE_MAYBE (base_dir); FREE_MAYBE (robots_host); first_time = 1; } /* Reset FIRST_TIME to 1, so that some action can be taken in recursive_retrieve(). */ void recursive_reset (void) { first_time = 1; } /* The core of recursive retrieving. Endless recursion is avoided by having all URL-s stored to a linked list of URL-s, which is checked before loading any URL. That way no URL can get loaded twice. The function also supports specification of maximum recursion depth and a number of other goodies. */ uerr_t recursive_retrieve (const char *file, const char *this_url) { char *constr, *filename, *newloc; char *canon_this_url = NULL; int dt, inl; int this_url_ftp; /* See below the explanation */ uerr_t err; struct urlinfo *rurl; urlpos *url_list, *cur_url; char *rfile; /* For robots */ struct urlinfo *u; assert (this_url != NULL); assert (file != NULL); /* If quota was exceeded earlier, bail out. */ if (opt.quota && (opt.downloaded > opt.quota)) return QUOTEXC; /* Cache the current URL in the list. */ if (first_time) { ulist = add_slist (ulist, this_url, 0); urls_downloaded = NULL; urls_html = NULL; /* Enter this_url to the slist, in original and "enhanced" form. */ u = newurl (); err = parseurl (this_url, u, 0); if (err == URLOK) { ulist = add_slist (ulist, u->url, 0); urls_downloaded = add_url (urls_downloaded, u->url, file); urls_html = add_slist (urls_html, file, NOSORT); if (opt.no_parent) base_dir = xstrdup (u->dir); /* Set the base dir. */ /* Set the canonical this_url to be sent as referer. This problem exists only when running the first time. */ canon_this_url = xstrdup (u->url); } else { DEBUGP (("Double yuck! The *base* URL is broken.\n")); base_dir = NULL; } freeurl (u, 1); depth = 1; robots_host = NULL; forbidden = NULL; first_time = 0; } else ++depth; /* Bail out if opt.reclevel is exceeded. */ if ((opt.reclevel != 0) && (depth > opt.reclevel)) { DEBUGP (("Recursion depth %d exceeded max. depth %d.\n", depth, opt.reclevel)); --depth; return RECLEVELEXC; } /* Determine whether this_url is an FTP URL. If it is, it means that the retrieval is done through proxy. In that case, FTP links will be followed by default and recursion will not be turned off when following them. */ this_url_ftp = (urlproto (this_url) == URLFTP); /* Get the URL-s from an HTML file: */ url_list = get_urls_html (file, canon_this_url ? canon_this_url : this_url, 0); /* Decide what to do with each of the URLs. A URL will be loaded if it meets several requirements, discussed later. */ for (cur_url = url_list; cur_url; cur_url = cur_url->next) { /* If quota was exceeded earlier, bail out. */ if (opt.quota && (opt.downloaded > opt.quota)) break; /* Parse the URL for convenient use in other functions, as well as to get the optimized form. It also checks URL integrity. */ u = newurl (); if (parseurl (cur_url->url, u, 0) != URLOK) { DEBUGP (("Yuck! A bad URL.\n")); freeurl (u, 1); continue; } if (u->proto == URLFILE) { DEBUGP (("Nothing to do with file:// around here.\n")); freeurl (u, 1); continue; } assert (u->url != NULL); constr = xstrdup (u->url); /* Several checkings whether a file is acceptable to load: 1. check if URL is ftp, and we don't load it 2. check for relative links (if relative_only is set) 3. check for domain 4. check for no-parent 5. check for excludes && includes 6. check for suffix 7. check for same host (if spanhost is unset), with possible gethostbyname baggage 8. check for robots.txt Addendum: If the URL is FTP, and it is to be loaded, only the domain and suffix settings are "stronger". Note that .html and (yuck) .htm will get loaded regardless of suffix rules (but that is remedied later with unlink) unless the depth equals the maximum depth. More time- and memory- consuming tests should be put later on the list. */ /* inl is set if the URL we are working on (constr) is stored in ulist. Using it is crucial to avoid the incessant calls to in_slist, which is quite slow. */ inl = in_slist (ulist, constr); /* If it is FTP, and FTP is not followed, chuck it out. */ if (!inl) if (u->proto == URLFTP && !opt.follow_ftp && !this_url_ftp) { DEBUGP (("Uh, it is FTP but i'm not in the mood to follow FTP.\n")); ulist = add_slist (ulist, constr, 0); inl = 1; } /* If it is absolute link and they are not followed, chuck it out. */ if (!inl && u->proto != URLFTP) if (opt.relative_only && !(cur_url->flags & URELATIVE)) { DEBUGP (("It doesn't really look like a relative link.\n")); ulist = add_slist (ulist, constr, 0); inl = 1; } /* If its domain is not to be accepted/looked-up, chuck it out. */ if (!inl) if (!accept_domain (u)) { DEBUGP (("I don't like the smell of that domain.\n")); ulist = add_slist (ulist, constr, 0); inl = 1; } /* Check for parent directory. */ if (!inl && opt.no_parent /* If the new URL is FTP and the old was not, ignore opt.no_parent. */ && !(!this_url_ftp && u->proto == URLFTP)) { /* Check for base_dir first. */ if (!(base_dir && frontcmp (base_dir, u->dir))) { /* Failing that, check for parent dir. */ struct urlinfo *ut = newurl (); if (parseurl (this_url, ut, 0) != URLOK) DEBUGP (("Double yuck! The *base* URL is broken.\n")); else if (!frontcmp (ut->dir, u->dir)) { /* Failing that too, kill the URL. */ DEBUGP (("Trying to escape parental guidance with no_parent on.\n")); ulist = add_slist (ulist, constr, 0); inl = 1; } freeurl (ut, 1); } } /* If the file does not match the acceptance list, or is on the rejection list, chuck it out. The same goes for the directory exclude- and include- lists. */ if (!inl && (opt.includes || opt.excludes)) { if (!accdir (u->dir, ALLABS)) { DEBUGP (("%s (%s) is excluded/not-included.\n", constr, u->dir)); ulist = add_slist (ulist, constr, 0); inl = 1; } } if (!inl) { char *suf = NULL; /* We check for acceptance/rejection rules only for non-HTML documents. Since we don't know whether they really are HTML, it will be deduced from (an OR-ed list): 1) u->file is "" (meaning it is a directory) 2) suffix exists, AND: a) it is "html", OR b) it is "htm" If the file *is* supposed to be HTML, it will *not* be subject to acc/rej rules, unless a finite maximum depth has been specified and the current depth is the maximum depth. */ if (! (!*u->file || (((suf = suffix (constr)) != NULL) && ((!strcmp (suf, "html") || !strcmp (suf, "htm")) && ((opt.reclevel != 0) && (depth != opt.reclevel)))))) { if (!acceptable (u->file)) { DEBUGP (("%s (%s) does not match acc/rej rules.\n", constr, u->file)); ulist = add_slist (ulist, constr, 0); inl = 1; } } FREE_MAYBE (suf); } /* Optimize the URL (which includes possible DNS lookup) only after all other possibilities have been exhausted. */ if (!inl) { if (!opt.simple_check) opt_url (u); else { char *p; /* Just lowercase the hostname. */ for (p = u->host; *p; p++) *p = tolower (*p); free (u->url); u->url = str_url (u, 0); } free (constr); constr = xstrdup (u->url); inl = in_slist (ulist, constr); if (!inl && !((u->proto == URLFTP) && !this_url_ftp)) if (!opt.spanhost && this_url && !same_host (this_url, constr)) { DEBUGP (("This is not the same hostname as the parent's.\n")); ulist = add_slist (ulist, constr, 0); inl = 1; } } /* What about robots.txt? */ if (!inl && opt.use_robots && u->proto == URLHTTP) { /* Since Wget knows about only one set of robot rules at a time, /robots.txt must be reloaded whenever a new host is accessed. robots_host holds the host the current `forbid' variable is assigned to. */ if (!robots_host || !same_host (robots_host, u->host)) { FREE_MAYBE (robots_host); /* Now make robots_host the new host, no matter what the result will be. So if there is no /robots.txt on the site, Wget will not retry getting robots all the time. */ robots_host = xstrdup (u->host); free_vec (forbidden); forbidden = NULL; err = retrieve_robots (constr, ROBOTS_FILENAME); if (err == ROBOTSOK) { rurl = robots_url (constr, ROBOTS_FILENAME); rfile = url_filename (rurl); forbidden = parse_robots (rfile); freeurl (rurl, 1); free (rfile); } } /* Now that we have (or don't have) robots, we can check for them. */ if (!robots_match (u, forbidden)) { DEBUGP (("Stuffing %s because %s forbids it.\n", this_url, ROBOTS_FILENAME)); ulist = add_slist (ulist, constr, 0); inl = 1; } } filename = NULL; /* If it wasn't chucked out, do something with it. */ if (!inl) { DEBUGP (("I've decided to load it -> ")); /* Add it to the list of already-loaded URL-s. */ ulist = add_slist (ulist, constr, 0); /* Automatically followed FTPs will *not* be downloaded recursively. */ if (u->proto == URLFTP) { /* Don't you adore side-effects? */ opt.recursive = 0; } /* Reset its type. */ dt = 0; /* Retrieve it. */ retrieve_url (constr, &filename, &newloc, canon_this_url ? canon_this_url : this_url, &dt); if (u->proto == URLFTP) { /* Restore... */ opt.recursive = 1; } if (newloc) { free (constr); constr = newloc; } /* In case of convert_links: If there was no error, add it to the list of downloaded URLs. We might need it for conversion. */ if (opt.convert_links && filename) { if (dt & RETROKF) { urls_downloaded = add_url (urls_downloaded, constr, filename); /* If the URL is HTML, note it. */ if (dt & TEXTHTML) urls_html = add_slist (urls_html, filename, NOSORT); } } /* If there was no error, and the type is text/html, parse it recursively. */ if (dt & TEXTHTML) { if (dt & RETROKF) recursive_retrieve (filename, constr); } else DEBUGP (("%s is not text/html so we don't chase.\n", filename ? filename: "(null)")); /* If an suffix-rejected file was loaded only because it was HTML, undo the error now */ if (opt.delete_after || (filename && !acceptable (filename))) { logprintf (LOG_VERBOSE, (opt.delete_after ? _("Removing %s.\n") : _("Removing %s since it should be rejected.\n")), filename); if (unlink (filename)) logprintf (LOG_NOTQUIET, "unlink: %s\n", strerror (errno)); dt &= ~RETROKF; } /* If everything was OK, and links are to be converted, let's store the local filename. */ if (opt.convert_links && (dt & RETROKF) && (filename != NULL)) { cur_url->flags |= UABS2REL; cur_url->local_name = xstrdup (filename); } } DEBUGP (("%s already in list, so we don't load.\n", constr)); /* Free filename and constr. */ FREE_MAYBE (filename); FREE_MAYBE (constr); freeurl (u, 1); /* Increment the pbuf for the appropriate size. */ } if (opt.convert_links) convert_links (file, url_list); /* Free the linked list of URL-s. */ free_urlpos (url_list); /* Free the canonical this_url. */ FREE_MAYBE (canon_this_url); /* Decrement the recursion depth. */ --depth; if (opt.quota && (opt.downloaded > opt.quota)) return QUOTEXC; else return RETROK; } /* Simple calls to convert_links will often fail because only the downloaded files are converted, and Wget cannot know which files will be converted in the future. So, if we have file fileone.html with: and /c/something.gif was not downloaded because it exceeded the recursion depth, the reference will *not* be changed. However, later we can encounter /c/something.gif from an "upper" level HTML (let's call it filetwo.html), and it gets downloaded. But now we have a problem because /c/something.gif will be correctly transformed in filetwo.html, but not in fileone.html, since Wget could not have known that /c/something.gif will be downloaded in the future. This is why Wget must, after the whole retrieval, call convert_all_links to go once more through the entire list of retrieved HTML-s, and re-convert them. All the downloaded HTMLs are kept in urls_html, and downloaded URLs in urls_downloaded. From these two lists information is extracted. */ void convert_all_links (void) { uerr_t res; urlpos *l1, *l2, *urls; struct urlinfo *u; slist *html; urlpos *urlhtml; for (html = urls_html; html; html = html->next) { DEBUGP (("Rescanning %s\n", html->string)); /* Determine the URL of the HTML file. get_urls_html will need it. */ for (urlhtml = urls_downloaded; urlhtml; urlhtml = urlhtml->next) if (!strcmp (urlhtml->local_name, html->string)) break; if (urlhtml) DEBUGP (("It should correspond to %s.\n", urlhtml->url)); else DEBUGP (("I cannot find the corresponding URL.\n")); /* Parse the HTML file... */ urls = get_urls_html (html->string, urlhtml ? urlhtml->url : NULL, 1); if (!urls) continue; for (l1 = urls; l1; l1 = l1->next) { /* The URL must be in canonical form to be compared. */ u = newurl (); res = parseurl (l1->url, u, 0); if (res != URLOK) { freeurl (u, 1); continue; } /* We decide the direction of conversion according to whether a URL was downloaded. Downloaded URLs will be converted ABS2REL, whereas non-downloaded will be converted REL2ABS. Note: not yet implemented; only ABS2REL works. */ for (l2 = urls_downloaded; l2; l2 = l2->next) if (!strcmp (l2->url, u->url)) { DEBUGP (("%s flagged for conversion, local %s\n", l2->url, l2->local_name)); break; } /* Clear the flags. */ l1->flags &= ~ (UABS2REL | UREL2ABS); /* Decide on the conversion direction. */ if (l2) { l1->flags |= UABS2REL; l1->local_name = xstrdup (l2->local_name); } else { l1->flags |= UREL2ABS; l1->local_name = NULL; } freeurl (u, 1); } /* Convert the links in the file. */ convert_links (html->string, urls); /* Free the data. */ free_urlpos (urls); } } /* Robots support. */ /* Construct the robots URL. */ static struct urlinfo * robots_url (const char *url, const char *robots_filename) { struct urlinfo *u = newurl (); uerr_t err; err = parseurl (url, u, 0); assert (err == URLOK && u->proto == URLHTTP); free (u->file); free (u->dir); free (u->url); u->dir = xstrdup (""); u->file = xstrdup (robots_filename); u->url = str_url (u, 0); return u; } /* Retrieves the robots_filename from the root server directory, if possible. Returns ROBOTSOK if robots were retrieved OK, and NOROBOTS if robots could not be retrieved for any reason. */ static uerr_t retrieve_robots (const char *url, const char *robots_filename) { int dt; uerr_t err; struct urlinfo *u; u = robots_url (url, robots_filename); logputs (LOG_VERBOSE, _("Loading robots.txt; please ignore errors.\n")); err = retrieve_url (u->url, NULL, NULL, NULL, &dt); freeurl (u, 1); if (err == RETROK) return ROBOTSOK; else return NOROBOTS; } /* Parse the robots_filename and return the disallowed path components in a malloc-ed vector of character pointers. It should be fully compliant with the syntax as described in the file norobots.txt, adopted by the robots mailing list (robots@webcrawler.com). */ static char ** parse_robots (const char *robots_filename) { FILE *fp; char **entries; char *line, *cmd, *str, *p; char *base_version, *version; int len, num, i; int wget_matched; /* is the part meant for Wget? */ entries = NULL; num = 0; fp = fopen (robots_filename, "rb"); if (!fp) return NULL; /* Kill version number. */ if (opt.useragent) { STRDUP_ALLOCA (base_version, opt.useragent); STRDUP_ALLOCA (version, opt.useragent); } else { int len = 10 + strlen (version_string); base_version = (char *)alloca (len); sprintf (base_version, "Wget/%s", version_string); version = (char *)alloca (len); sprintf (version, "Wget/%s", version_string); } for (p = version; *p; p++) *p = tolower (*p); for (p = base_version; *p && *p != '/'; p++) *p = tolower (*p); *p = '\0'; /* Setting this to 1 means that Wget considers itself under restrictions by default, even if the User-Agent field is not present. However, if it finds the user-agent set to anything other than Wget, the rest will be ignored (up to the following User-Agent field). Thus you may have something like: Disallow: 1 Disallow: 2 User-Agent: stupid-robot Disallow: 3 Disallow: 4 User-Agent: Wget* Disallow: 5 Disallow: 6 User-Agent: * Disallow: 7 In this case the 1, 2, 5, 6 and 7 disallow lines will be stored. */ wget_matched = 1; while ((line = read_whole_line (fp))) { len = strlen (line); /* Destroy if there is one. */ if (len && line[len - 1] == '\r') line[len - 1] = '\0'; /* According to specifications, optional space may be at the end... */ DEBUGP (("Line: %s\n", line)); /* Skip spaces. */ for (cmd = line; *cmd && ISSPACE (*cmd); cmd++); if (!*cmd) { free (line); DEBUGP (("(chucked out)\n")); continue; } /* Look for ':'. */ for (str = cmd; *str && *str != ':'; str++); if (!*str) { free (line); DEBUGP (("(chucked out)\n")); continue; } /* Zero-terminate the command. */ *str++ = '\0'; /* Look for the string beginning... */ for (; *str && ISSPACE (*str); str++); /* Look for comments or trailing spaces and kill them off. */ for (p = str; *p; p++) if (*p && ISSPACE (*p) && ((*(p + 1) == '#') || (*(p + 1) == '\0'))) { /* We have found either a shell-style comment `+#' or some trailing spaces. Now rewind to the beginning of the spaces and place '\0' there. */ while (p > str && ISSPACE (*p)) --p; if (p == str) *p = '\0'; else *(p + 1) = '\0'; break; } if (!strcasecmp (cmd, "User-agent")) { int match = 0; /* Lowercase the agent string. */ for (p = str; *p; p++) *p = tolower (*p); /* If the string is `*', it matches. */ if (*str == '*' && !*(str + 1)) match = 1; else { /* If the string contains wildcards, we'll run it through fnmatch(). */ if (has_wildcards_p (str)) { /* If the string contains '/', compare with the full version. Else, compare it to base_version. */ if (strchr (str, '/')) match = !fnmatch (str, version, 0); else match = !fnmatch (str, base_version, 0); } else /* Substring search */ { if (strstr (version, str)) match = 1; else match = 0; } } /* If Wget is not matched, skip all the entries up to the next User-agent field. */ wget_matched = match; } else if (!wget_matched) { free (line); DEBUGP (("(chucking out since it is not applicable for Wget)\n")); continue; } else if (!strcasecmp (cmd, "Disallow")) { /* If "Disallow" is empty, the robot is welcome. */ if (!*str) { free_vec (entries); entries = (char **)xmalloc (sizeof (char *)); *entries = NULL; num = 0; } else { entries = (char **)xrealloc (entries, (num + 2)* sizeof (char *)); entries[num] = xstrdup (str); entries[++num] = NULL; /* Strip trailing spaces, according to specifications. */ for (i = strlen (str); i >= 0 && ISSPACE (str[i]); i--) if (ISSPACE (str[i])) str[i] = '\0'; } } else { /* unknown command */ DEBUGP (("(chucked out)\n")); } free (line); } fclose (fp); return entries; } /* May the URL url be loaded according to disallowing rules stored in forbidden? */ static int robots_match (struct urlinfo *u, char **forbidden) { int l; if (!forbidden) return 1; DEBUGP (("Matching %s against: ", u->path)); for (; *forbidden; forbidden++) { DEBUGP (("%s ", *forbidden)); l = strlen (*forbidden); /* If dir is forbidden, we may not load the file. */ if (strncmp (u->path, *forbidden, l) == 0) { DEBUGP (("matched.\n")); return 0; /* Matches, i.e. does not load... */ } } DEBUGP (("not matched.\n")); return 1; }