parsing.c: be prepared for unexpected content in commit/tag objects

When parsing commits and tags cgit made too many assumptions about the
formatting of said objects. This patch tries to make the code be more
prepared to handle 'malformed' objects.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 96 insertions, 63 deletions

diff --git a/parsing.c b/parsing.c
index 66e8b3d..c8f3048 100644
--- a/parsing.c
+++ b/parsing.c
@@ -1,208 +1,241 @@
 /* config.c: parsing of config files
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 
 /*
  * url syntax: [repo ['/' cmd [ '/' path]]]
  *   repo: any valid repo url, may contain '/'
  *   cmd:  log | commit | diff | tree | view | blob | snapshot
  *   path: any valid path, may contain '/'
  *
  */
 void cgit_parse_url(const char *url)
 {
         char *cmd, *p;
 
         ctx.repo = NULL;
         if (!url || url[0] == '\0')
                 return;
 
         ctx.repo = cgit_get_repoinfo(url);
         if (ctx.repo) {
                 ctx.qry.repo = ctx.repo->url;
                 return;
         }
 
         cmd = strchr(url, '/');
         while (!ctx.repo && cmd) {
                 cmd[0] = '\0';
                 ctx.repo = cgit_get_repoinfo(url);
                 if (ctx.repo == NULL) {
                         cmd[0] = '/';
                         cmd = strchr(cmd + 1, '/');
                         continue;
                 }
 
                 ctx.qry.repo = ctx.repo->url;
                 p = strchr(cmd + 1, '/');
                 if (p) {
                         p[0] = '\0';
                         if (p[1])
                                 ctx.qry.path = trim_end(p + 1, '/');
                 }
                 if (cmd[1])
                         ctx.qry.page = xstrdup(cmd + 1);
                 return;
         }
 }
 
 char *substr(const char *head, const char *tail)
 {
         char *buf;
 
         buf = xmalloc(tail - head + 1);
         strncpy(buf, head, tail - head);
         buf[tail - head] = '\0';
         return buf;
 }
 
+char *parse_user(char *t, char **name, char **email, unsigned long *date)
+{
+        char *p = t;
+        int mode = 1;
+
+        while (p && *p) {
+                if (mode == 1 && *p == '<') {
+                        *name = substr(t, p - 1);
+                        t = p;
+                        mode++;
+                } else if (mode == 1 && *p == '\n') {
+                        *name = substr(t, p);
+                        p++;
+                        break;
+                } else if (mode == 2 && *p == '>') {
+                        *email = substr(t, p + 1);
+                        t = p;
+                        mode++;
+                } else if (mode == 2 && *p == '\n') {
+                        *email = substr(t, p);
+                        p++;
+                        break;
+                } else if (mode == 3 && isdigit(*p)) {
+                        *date = atol(p);
+                        mode++;
+                } else if (*p == '\n') {
+                        p++;
+                        break;
+                }
+                p++;
+        }
+        return p;
+}
+
+const char *reencode(char **txt, const char *src_enc, const char *dst_enc)
+{
+        char *tmp;
+
+        if (!txt || !*txt || !src_enc || !dst_enc)
+                return *txt;
+
+        tmp = reencode_string(*txt, src_enc, dst_enc);
+        if (tmp) {
+                free(*txt);
+                *txt = tmp;
+        }
+        return *txt;
+}
+
 struct commitinfo *cgit_parse_commit(struct commit *commit)
 {
         struct commitinfo *ret;
         char *p = commit->buffer, *t = commit->buffer;
 
         ret = xmalloc(sizeof(*ret));
         ret->commit = commit;
         ret->author = NULL;
         ret->author_email = NULL;
         ret->committer = NULL;
         ret->committer_email = NULL;
         ret->subject = NULL;
         ret->msg = NULL;
         ret->msg_encoding = NULL;
 
         if (p == NULL)
                 return ret;
 
         if (strncmp(p, "tree ", 5))
                 die("Bad commit: %s", sha1_to_hex(commit->object.sha1));
         else
                 p += 46; // "tree " + hex[40] + "\n"
 
         while (!strncmp(p, "parent ", 7))
                 p += 48; // "parent " + hex[40] + "\n"
 
-        if (!strncmp(p, "author ", 7)) {
-                p += 7;
-                t = strchr(p, '<') - 1;
-                ret->author = substr(p, t);
-                p = t;
-                t = strchr(t, '>') + 1;
-                ret->author_email = substr(p, t);
-                ret->author_date = atol(t+1);
-                p = strchr(t, '\n') + 1;
+        if (p && !strncmp(p, "author ", 7)) {
+                p = parse_user(p + 7, &ret->author, &ret->author_email,
+                        &ret->author_date);
         }
 
-        if (!strncmp(p, "committer ", 9)) {
-                p += 9;
-                t = strchr(p, '<') - 1;
-                ret->committer = substr(p, t);
-                p = t;
-                t = strchr(t, '>') + 1;
-                ret->committer_email = substr(p, t);
-                ret->committer_date = atol(t+1);
-                p = strchr(t, '\n') + 1;
+        if (p && !strncmp(p, "committer ", 9)) {
+                p = parse_user(p + 9, &ret->committer, &ret->committer_email,
+                        &ret->committer_date);
         }
 
-        if (!strncmp(p, "encoding ", 9)) {
+        if (p && !strncmp(p, "encoding ", 9)) {
                 p += 9;
-                t = strchr(p, '\n') + 1;
-                ret->msg_encoding = substr(p, t);
-                p = t;
-        } else
-                ret->msg_encoding = xstrdup(PAGE_ENCODING);
+                t = strchr(p, '\n');
+                if (t) {
+                        ret->msg_encoding = substr(p, t + 1);
+                        p = t + 1;
+                }
+        }
 
-        while (*p && (*p != '\n'))
-                p = strchr(p, '\n') + 1; // skip unknown header fields
+        // skip unknown header fields
+        while (p && *p && (*p != '\n')) {
+                p = strchr(p, '\n');
+                if (p)
+                        p++;
+        }
 
-        while (*p == '\n')
-                p = strchr(p, '\n') + 1;
+        // skip empty lines between headers and message
+        while (p && *p == '\n')
+                p++;
+
+        if (!p)
+                return ret;
 
         t = strchr(p, '\n');
         if (t) {
-                if (*t == '\0')
-                        ret->subject = "** empty **";
-                else
-                        ret->subject = substr(p, t);
+                ret->subject = substr(p, t);
                 p = t + 1;
 
-                while (*p == '\n')
-                        p = strchr(p, '\n') + 1;
-                ret->msg = xstrdup(p);
-        } else
-                ret->subject = substr(p, p+strlen(p));
-
-        if(strcmp(ret->msg_encoding, PAGE_ENCODING)) {
-                t = reencode_string(ret->subject, PAGE_ENCODING,
-                                    ret->msg_encoding);
-                if(t) {
-                        free(ret->subject);
-                        ret->subject = t;
+                while (p && *p == '\n') {
+                        p = strchr(p, '\n');
+                        if (p)
+                                p++;
                 }
+                if (p)
+                        ret->msg = xstrdup(p);
+        } else
+                ret->subject = xstrdup(p);
 
-                t = reencode_string(ret->msg, PAGE_ENCODING,
-                                    ret->msg_encoding);
-                if(t) {
-                        free(ret->msg);
-                        ret->msg = t;
-                }
+        if (ret->msg_encoding) {
+                reencode(&ret->subject, PAGE_ENCODING, ret->msg_encoding);
+                reencode(&ret->msg, PAGE_ENCODING, ret->msg_encoding);
         }
 
         return ret;
 }
 
 
 struct taginfo *cgit_parse_tag(struct tag *tag)
 {
         void *data;
         enum object_type type;
         unsigned long size;
-        char *p, *t;
+        char *p;
         struct taginfo *ret;
 
         data = read_sha1_file(tag->object.sha1, &type, &size);
         if (!data || type != OBJ_TAG) {
                 free(data);
                 return 0;
         }
 
         ret = xmalloc(sizeof(*ret));
         ret->tagger = NULL;
         ret->tagger_email = NULL;
         ret->tagger_date = 0;
         ret->msg = NULL;
 
         p = data;
 
         while (p && *p) {
                 if (*p == '\n')
                         break;
 
                 if (!strncmp(p, "tagger ", 7)) {
-                        p += 7;
-                        t = strchr(p, '<') - 1;
-                        ret->tagger = substr(p, t);
-                        p = t;
-                        t = strchr(t, '>') + 1;
-                        ret->tagger_email = substr(p, t);
-                        ret->tagger_date = atol(t+1);
+                        p = parse_user(p + 7, &ret->tagger, &ret->tagger_email,
+                                &ret->tagger_date);
+                } else {
+                        p = strchr(p, '\n');
+                        if (p)
+                                p++;
                 }
-                p = strchr(p, '\n') + 1;
         }
 
-        while (p && *p && (*p != '\n'))
-                p = strchr(p, '\n') + 1; // skip unknown tag fields
+        // skip empty lines between headers and message
+        while (p && *p == '\n')
+                p++;
 
-        while (p && (*p == '\n'))
-                p = strchr(p, '\n') + 1;
         if (p && *p)
                 ret->msg = xstrdup(p);
         free(data);
         return ret;
 }