PR/367: Brooks Davis: Add magic_load_buffers to provide a means to load the

magic database on environments that have no direct access to the filesystem.

1 files changed, 116 insertions, 24 deletions

diff --git a/src/apprentice.c b/src/apprentice.c
index 715c26ec..cdb830c8 100644
--- a/src/apprentice.c
+++ b/src/apprentice.c
@@ -32,7 +32,7 @@
 #include "file.h"
 
 #ifndef	lint
-FILE_RCSID("@(#)$File: apprentice.c,v 1.212 2014/06/26 12:53:36 christos Exp $")
+FILE_RCSID("@(#)$File: apprentice.c,v 1.213 2014/08/04 06:19:44 christos Exp $")
 #endif	/* lint */
 
 #include "magic.h"
@@ -86,6 +86,10 @@ FILE_RCSID("@(#)$File: apprentice.c,v 1.212 2014/06/26 12:53:36 christos Exp $")
 #define ALLOC_CHUNK	(size_t)10
 #define ALLOC_INCR	(size_t)200
 
+#define MAP_TYPE_MMAP	0
+#define MAP_TYPE_MALLOC	1
+#define MAP_TYPE_USER	2
+
 struct magic_entry {
 	struct magic *mp;	
 	uint32_t cont_count;
@@ -101,6 +105,7 @@ struct magic_entry_set {
 struct magic_map {
 	void *p;
 	size_t len;
+	int type;
 	struct magic *magic[MAGIC_SETS];
 	uint32_t nmagic[MAGIC_SETS];
 };
@@ -131,7 +136,10 @@ private uint16_t swap2(uint16_t);
 private uint32_t swap4(uint32_t);
 private uint64_t swap8(uint64_t);
 private char *mkdbname(struct magic_set *, const char *, int);
+private struct magic_map *apprentice_buf(struct magic_set *, struct magic *,
+    size_t);
 private struct magic_map *apprentice_map(struct magic_set *, const char *);
+private int check_buffer(struct magic_set *, struct magic_map *, const char *);
 private void apprentice_unmap(struct magic_map *);
 private int apprentice_compile(struct magic_set *, struct magic_map *,
     const char *);
@@ -518,9 +526,9 @@ apprentice_unmap(struct magic_map *map)
 {
 	if (map == NULL)
 		return;
-	if (map->p != NULL) {
+	if (map->p != NULL && map->type != MAP_TYPE_USER) {
 #ifdef QUICK
-		if (map->len)
+		if (map->type == MAP_TYPE_MMAP)
 			(void)munmap(map->p, map->len);
 		else
 #endif
@@ -562,6 +570,56 @@ mlist_free(struct mlist *mlist)
 	free(ml);
 }
 
+#ifndef COMPILE_ONLY
+/* void **bufs: an array of compiled magic files */
+protected int
+buffer_apprentice(struct magic_set *ms, struct magic **bufs,
+    size_t *sizes, size_t nbufs)
+{
+	size_t i;
+	struct mlist *ml;
+	struct magic_map *map;
+
+	if (nbufs == 0)
+		return -1;
+
+	if (ms->mlist[0] != NULL)
+		file_reset(ms);
+
+	init_file_tables();
+
+	for (i = 0; i < MAGIC_SETS; i++) {
+		mlist_free(ms->mlist[i]);
+		if ((ms->mlist[i] = mlist_alloc()) == NULL) {
+			file_oomem(ms, sizeof(*ms->mlist[i]));
+			if (i != 0) {
+				--i;
+				do
+					mlist_free(ms->mlist[i]);
+				while (i != 0);
+			}
+			return -1;
+		}
+	}
+
+	for (i = 0; i < nbufs; i++) {
+		map = apprentice_buf(ms, bufs[i], sizes[i]);
+		if (map == NULL)
+			return -1;
+
+		for (i = 0; i < MAGIC_SETS; i++) {
+			if (add_mlist(ms->mlist[i], map, i) == -1) {
+				file_oomem(ms, sizeof(*ml));
+				apprentice_unmap(map);
+				return -1;
+			}
+		}
+	}
+
+	return 0;
+}
+#endif
+
 /* const char *fn: list of magic files and directories */
 protected int
 file_apprentice(struct magic_set *ms, const char *fn, int action)
@@ -2694,6 +2752,28 @@ eatsize(const char **p)
 }
 
 /*
+ * handle a buffer containging a compiled file.
+ */
+private struct magic_map *
+apprentice_buf(struct magic_set *ms, struct magic *buf, size_t len)
+{
+	struct magic_map *map;
+
+	if ((map = CAST(struct magic_map *, calloc(1, sizeof(*map)))) == NULL) {
+		file_oomem(ms, sizeof(*map));
+		return NULL;
+	}
+	map->len = len;
+	map->p = buf;
+	map->type = MAP_TYPE_USER;
+	if (check_buffer(ms, map, "buffer") != 0) {
+		apprentice_unmap(map);
+		return NULL;
+	}
+	return map;
+}
+
+/*
  * handle a compiled file.
  */
 
@@ -2702,12 +2782,8 @@ apprentice_map(struct magic_set *ms, const char *fn)
 {
 	int fd;
 	struct stat st;
-	uint32_t *ptr;
-	uint32_t version, entries, nentries;
-	int needsbyteswap;
 	char *dbname = NULL;
 	struct magic_map *map;
-	size_t i;
 
 	fd = -1;
 	if ((map = CAST(struct magic_map *, calloc(1, sizeof(*map)))) == NULL) {
@@ -2739,6 +2815,7 @@ apprentice_map(struct magic_set *ms, const char *fn)
 		file_error(ms, errno, "cannot map `%s'", dbname);
 		goto error;
 	}
+	map->type = MAP_TYPE_MMAP;
 #else
 	if ((map->p = CAST(void *, malloc(map->len))) == NULL) {
 		file_oomem(ms, map->len);
@@ -2748,16 +2825,39 @@ apprentice_map(struct magic_set *ms, const char *fn)
 		file_badread(ms);
 		goto error;
 	}
-	map->len = 0;
+	map->type = MAP_TYPE_MALLOC;
 #define RET	1
 #endif
 	(void)close(fd);
 	fd = -1;
+
+	if (check_buffer(ms, map, dbname) != 0)
+		goto error;
+
+	free(dbname);
+	return map;
+
+error:
+	if (fd != -1)
+		(void)close(fd);
+	apprentice_unmap(map);
+	free(dbname);
+	return NULL;
+}
+
+private int
+check_buffer(struct magic_set *ms, struct magic_map *map, const char *dbname)
+{
+	uint32_t *ptr;
+	uint32_t entries, nentries;
+	uint32_t version;
+	int i, needsbyteswap;
+
 	ptr = CAST(uint32_t *, map->p);
 	if (*ptr != MAGICNO) {
 		if (swap4(*ptr) != MAGICNO) {
 			file_error(ms, 0, "bad magic in `%s'", dbname);
-			goto error;
+			return -1;
 		}
 		needsbyteswap = 1;
 	} else
@@ -2770,15 +2870,15 @@ apprentice_map(struct magic_set *ms, const char *fn)
 		file_error(ms, 0, "File %s supports only version %d magic "
 		    "files. `%s' is version %d", VERSION,
 		    VERSIONNO, dbname, version);
-		goto error;
+		return -1;
 	}
-	entries = (uint32_t)(st.st_size / sizeof(struct magic));
-	if ((off_t)(entries * sizeof(struct magic)) != st.st_size) {
+	entries = (uint32_t)(map->len / sizeof(struct magic));
+	if ((entries * sizeof(struct magic)) != map->len) {
 		file_error(ms, 0, "Size of `%s' %" INT64_T_FORMAT "u is not "
 		    "a multiple of %" SIZE_T_FORMAT "u",
-		    dbname, (unsigned long long)st.st_size,
+		    dbname, (unsigned long long)map->len,
 		    sizeof(struct magic));
-		goto error;
+		return -1;
 	}
 	map->magic[0] = CAST(struct magic *, map->p) + 1;
 	nentries = 0;
@@ -2794,20 +2894,12 @@ apprentice_map(struct magic_set *ms, const char *fn)
 	if (entries != nentries + 1) {
 		file_error(ms, 0, "Inconsistent entries in `%s' %u != %u",
 		    dbname, entries, nentries + 1);
-		goto error;
+		return -1;
 	}
 	if (needsbyteswap)
 		for (i = 0; i < MAGIC_SETS; i++)
 			byteswap(map->magic[i], map->nmagic[i]);
-	free(dbname);
-	return map;
-
-error:
-	if (fd != -1)
-		(void)close(fd);
-	apprentice_unmap(map);
-	free(dbname);
-	return NULL;
+	return -1;
 }
 
 /*