FILE() now supports line-mode and writing (altering) files.

(closes issue #16461)
 Reported by: skyman
 Patches: 
       20100622__issue16461.diff.txt uploaded by tilghman (license 14)
 Tested by: tilghman
 
Review: https://reviewboard.asterisk.org/r/737/


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@276114 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 1001 insertions, 48 deletions

diff --git a/funcs/func_env.c b/funcs/func_env.c
index e9ddd4163..f5814aec3 100644
--- a/funcs/func_env.c
+++ b/funcs/func_env.c
@@ -1,7 +1,7 @@
 /*
  * Asterisk -- An open source telephony toolkit.
  *
- * Copyright (C) 1999 - 2006, Digium, Inc.
+ * Copyright (C) 1999 - 2010, Digium, Inc.
  *
  * See http://www.asterisk.org for more information about
  * the Asterisk project. Please do not directly contact
@@ -17,7 +17,7 @@
 /*! \file
  *
  * \brief Environment related dialplan functions
- * 
+ *
  * \ingroup functions
  */
 
@@ -25,13 +25,14 @@
 
 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 
-#include <sys/stat.h>
+#include <sys/stat.h>   /* stat(2) */
 
 #include "asterisk/module.h"
 #include "asterisk/channel.h"
 #include "asterisk/pbx.h"
 #include "asterisk/utils.h"
 #include "asterisk/app.h"
+#include "asterisk/file.h"
 
 /*** DOCUMENTATION
 	<function name="ENV" language="en_US">
@@ -70,26 +71,158 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 	</function>
 	<function name="FILE" language="en_US">
 		<synopsis>
-			Obtains the contents of a file.
+			Read or write text file.
 		</synopsis>
 		<syntax>
 			<parameter name="filename" required="true" />
-			<parameter name="offset" required="true">
+			</parameter>
+			<parameter name="offset">
 				<para>Maybe specified as any number. If negative, <replaceable>offset</replaceable> specifies the number
 				of bytes back from the end of the file.</para>
 			</parameter>
-			<parameter name="length" required="true">
+			<parameter name="length">
 				<para>If specified, will limit the length of the data read to that size. If negative,
 				trims <replaceable>length</replaceable> bytes from the end of the file.</para>
 			</parameter>
+			<parameter name="options">
+				<optionlist>
+					<option name="l">
+						<para>Line mode:  offset and length are assumed to be
+						measured in lines, instead of byte offsets.</para>
+					</option>
+					<option name="a">
+						<para>In write mode only, the append option is used to
+						append to the end of the file, instead of overwriting
+						the existing file.</para>
+					</option>
+					<option name="d">
+						<para>In write mode and line mode only, this option does
+						not automatically append a newline string to the end of
+						a value.  This is useful for deleting lines, instead of
+						setting them to blank.</para>
+					</option>
+				</optionlist>
+			</parameter>
+			<parameter name="format">
+				<para>The <replaceable>format</replaceable> parameter may be
+				used to delimit the type of line terminators in line mode.</para>
+				<optionlist>
+					<option name="u">
+						<para>Unix newline format.</para>
+					</option>
+					<option name="d">
+						<para>DOS newline format.</para>
+					</option>
+					<option name="m">
+						<para>Macintosh newline format.</para>
+					</option>
+				</optionlist>
+			</parameter>
+		</syntax>
+		<description>
+			<para>Read and write text file in character and line mode.</para>
+			<para>Examples:</para>
+			<para/>
+			<para>Read mode (byte):</para>
+			<para>    ;reads the entire content of the file.</para>
+			<para>    Set(foo=${FILE(/tmp/test.txt)})</para>
+			<para>    ;reads from the 11th byte to the end of the file (i.e. skips the first 10).</para>
+			<para>    Set(foo=${FILE(/tmp/test.txt,10)})</para>
+			<para>    ;reads from the 11th to 20th byte in the file (i.e. skip the first 10, then read 10 bytes).</para>
+			<para>    Set(foo=${FILE(/tmp/test.txt,10,10)})</para>
+			<para/>
+			<para>Read mode (line):</para>
+			<para>    ; reads the 3rd line of the file.</para>
+			<para>    Set(foo=${FILE(/tmp/test.txt,3,1,l)})</para>
+			<para>    ; reads the 3rd and 4th lines of the file.</para>
+			<para>    Set(foo=${FILE(/tmp/test.txt,3,2,l)})</para>
+			<para>    ; reads from the third line to the end of the file.</para>
+			<para>    Set(foo=${FILE(/tmp/test.txt,3,,l)})</para>
+			<para>    ; reads the last three lines of the file.</para>
+			<para>    Set(foo=${FILE(/tmp/test.txt,-3,,l)})</para>
+			<para>    ; reads the 3rd line of a DOS-formatted file.</para>
+			<para>    Set(foo=${FILE(/tmp/test.txt,3,1,l,d)})</para>
+			<para/>
+			<para>Write mode (byte):</para>
+			<para>    ; truncate the file and write "bar"</para>
+			<para>    Set(FILE(/tmp/test.txt)=bar)</para>
+			<para>    ; Append "bar"</para>
+			<para>    Set(FILE(/tmp/test.txt,,,a)=bar)</para>
+			<para>    ; Replace the first byte with "bar" (replaces 1 character with 3)</para>
+			<para>    Set(FILE(/tmp/test.txt,0,1)=bar)</para>
+			<para>    ; Replace 10 bytes beginning at the 21st byte of the file with "bar"</para>
+			<para>    Set(FILE(/tmp/test.txt,20,10)=bar)</para>
+			<para>    ; Replace all bytes from the 21st with "bar"</para>
+			<para>    Set(FILE(/tmp/test.txt,20)=bar)</para>
+			<para>    ; Insert "bar" after the 4th character</para>
+			<para>    Set(FILE(/tmp/test.txt,4,0)=bar)</para>
+			<para/>
+			<para>Write mode (line):</para>
+			<para>    ; Replace the first line of the file with "bar"</para>
+			<para>    Set(FILE(/tmp/foo.txt,0,1,l)=bar)</para>
+			<para>    ; Replace the last line of the file with "bar"</para>
+			<para>    Set(FILE(/tmp/foo.txt,-1,,l)=bar)</para>
+			<para>    ; Append "bar" to the file with a newline</para>
+			<para>    Set(FILE(/tmp/foo.txt,,,al)=bar)</para>
+		</description>
+		<see-also>
+			<ref type="function">FILE_COUNT_LINE</ref>
+			<ref type="function">FILE_FORMAT</ref>
+		</see-also>
+	</function>
+	<function name="FILE_COUNT_LINE" language="en_US">
+		<synopsis>
+			Obtains the number of lines of a text file.
+		</synopsis>
+		<syntax>
+			<parameter name="filename" required="true" />
+			<parameter name="format">
+				<para>Format may be one of the following:</para>
+				<optionlist>
+					<option name="u">
+						<para>Unix newline format.</para>
+					</option>
+					<option name="d">
+						<para>DOS newline format.</para>
+					</option>
+					<option name="m">
+						<para>Macintosh newline format.</para>
+					</option>
+				</optionlist>
+				<note><para>If not specified, an attempt will be made to determine the newline format type.</para></note>
+			</parameter>
+		</syntax>
+		<description>
+			<para>Returns the number of lines, or <literal>-1</literal> on error.</para>
+		</description>
+		<see-also>
+			<ref type="function">FILE</ref>
+			<ref type="function">FILE_FORMAT</ref>
+		</see-also>
+	</function>
+	<function name="FILE_FORMAT" language="en_US">
+		<synopsis>
+			Return the newline format of a text file.
+		</synopsis>
+		<syntax>
+			<parameter name="filename" required="true" />
 		</syntax>
 		<description>
+			<para>Return the line terminator type:</para>
+			<para>'u' - Unix "\n" format</para>
+			<para>'d' - DOS "\r\n" format</para>
+			<para>'m' - Macintosh "\r" format</para>
+			<para>'x' - Cannot be determined</para>
 		</description>
+		<see-also>
+			<ref type="function">FILE</ref>
+			<ref type="function">FILE_COUNT_LINE</ref>
+		</see-also>
 	</function>
  ***/
 
 static int env_read(struct ast_channel *chan, const char *cmd, char *data,
-		    char *buf, size_t len)
+			char *buf, size_t len)
 {
 	char *ret = NULL;
 
@@ -105,7 +238,7 @@ static int env_read(struct ast_channel *chan, const char *cmd, char *data,
 }
 
 static int env_write(struct ast_channel *chan, const char *cmd, char *data,
-		     const char *value)
+			 const char *value)
 {
 	if (!ast_strlen_zero(data) && strncmp(data, "AST_", 4)) {
 		if (!ast_strlen_zero(value)) {
@@ -119,7 +252,7 @@ static int env_write(struct ast_channel *chan, const char *cmd, char *data,
 }
 
 static int stat_read(struct ast_channel *chan, const char *cmd, char *data,
-		     char *buf, size_t len)
+			 char *buf, size_t len)
 {
 	char *action;
 	struct stat s;
@@ -161,66 +294,874 @@ static int stat_read(struct ast_channel *chan, const char *cmd, char *data,
 	return 0;
 }
 
-static int file_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
+enum file_format {
+	FF_UNKNOWN = -1,
+	FF_UNIX,
+	FF_DOS,
+	FF_MAC,
+};
+
+static int64_t count_lines(const char *filename, enum file_format newline_format)
+{
+	int count = 0;
+	char fbuf[4096];
+	FILE *ff;
+
+	if (!(ff = fopen(filename, "r"))) {
+		ast_log(LOG_ERROR, "Unable to open '%s': %s\n", filename, strerror(errno));
+		return -1;
+	}
+
+	while (fgets(fbuf, sizeof(fbuf), ff)) {
+		char *next = fbuf, *first_cr = NULL, *first_nl = NULL;
+
+		/* Must do it this way, because if the fileformat is FF_MAC, then Unix
+		 * assumptions about line-format will not come into play. */
+		while (next) {
+			if (newline_format == FF_DOS || newline_format == FF_MAC || newline_format == FF_UNKNOWN) {
+				first_cr = strchr(next, '\r');
+			}
+			if (newline_format == FF_UNIX || newline_format == FF_UNKNOWN) {
+				first_nl = strchr(next, '\n');
+			}
+
+			/* No terminators found in buffer */
+			if (!first_cr && !first_nl) {
+				break;
+			}
+
+			if (newline_format == FF_UNKNOWN) {
+				if ((first_cr && !first_nl) || (first_cr && first_cr < first_nl)) {
+					if (first_nl && first_nl == first_cr + 1) {
+						newline_format = FF_DOS;
+					} else if (first_cr && first_cr == &fbuf[sizeof(fbuf) - 2]) {
+						/* Get it on the next pass */
+						fseek(ff, -1, SEEK_CUR);
+						break;
+					} else {
+						newline_format = FF_MAC;
+						first_nl = NULL;
+					}
+				} else {
+					newline_format = FF_UNIX;
+					first_cr = NULL;
+				}
+				/* Jump down into next section */
+			}
+
+			if (newline_format == FF_DOS) {
+				if (first_nl && first_cr && first_nl == first_cr + 1) {
+					next = first_nl + 1;
+					count++;
+				} else if (first_cr == &fbuf[sizeof(fbuf) - 2]) {
+					/* Get it on the next pass */
+					fseek(ff, -1, SEEK_CUR);
+					break;
+				}
+			} else if (newline_format == FF_MAC) {
+				if (first_cr) {
+					next = first_cr + 1;
+					count++;
+				}
+			} else if (newline_format == FF_UNIX) {
+				if (first_nl) {
+					next = first_nl + 1;
+					count++;
+				}
+			}
+		}
+	}
+	fclose(ff);
+
+	return count;
+}
+
+static int file_count_line(struct ast_channel *chan, const char *cmd, char *data, struct ast_str **buf, ssize_t len)
 {
+	enum file_format newline_format = FF_UNKNOWN;
+	int64_t count;
+	AST_DECLARE_APP_ARGS(args,
+		AST_APP_ARG(filename);
+		AST_APP_ARG(format);
+	);
+
+	AST_STANDARD_APP_ARGS(args, data);
+	if (args.argc > 1) {
+		if (tolower(args.format[0]) == 'd') {
+			newline_format = FF_DOS;
+		} else if (tolower(args.format[0]) == 'm') {
+			newline_format = FF_MAC;
+		} else if (tolower(args.format[0]) == 'u') {
+			newline_format = FF_UNIX;
+		}
+	}
+
+	count = count_lines(args.filename, newline_format);
+	ast_str_set(buf, len, "%" PRId64, count);
+	return 0;
+}
+
+#define LINE_COUNTER(cptr, term, counter) \
+	if (*cptr == '\n' && term == FF_UNIX) { \
+		counter++; \
+	} else if (*cptr == '\n' && term == FF_DOS && dos_state == 0) { \
+		dos_state = 1; \
+	} else if (*cptr == '\r' && term == FF_DOS && dos_state == 1) { \
+		dos_state = 0; \
+		counter++; \
+	} else if (*cptr == '\r' && term == FF_MAC) { \
+		counter++; \
+	} else if (term == FF_DOS) { \
+		dos_state = 0; \
+	}
+
+static enum file_format file2format(const char *filename)
+{
+	FILE *ff;
+	char fbuf[4096];
+	char *first_cr, *first_nl;
+	enum file_format newline_format = FF_UNKNOWN;
+
+	if (!(ff = fopen(filename, "r"))) {
+		ast_log(LOG_ERROR, "Cannot open '%s': %s\n", filename, strerror(errno));
+		return -1;
+	}
+
+	while (fgets(fbuf, sizeof(fbuf), ff)) {
+		first_cr = strchr(fbuf, '\r');
+		first_nl = strchr(fbuf, '\n');
+
+		if (!first_cr && !first_nl) {
+			continue;
+		}
+
+		if ((first_cr && !first_nl) || (first_cr && first_cr < first_nl)) {
+
+			if (first_nl && first_nl == first_cr + 1) {
+				newline_format = FF_DOS;
+			} else if (first_cr && first_cr == &fbuf[sizeof(fbuf) - 2]) {
+				/* Edge case: get it on the next pass */
+				fseek(ff, -1, SEEK_CUR);
+				continue;
+			} else {
+				newline_format = FF_MAC;
+			}
+		} else {
+			newline_format = FF_UNIX;
+		}
+		break;
+	}
+	fclose(ff);
+	return newline_format;
+}
+
+static int file_format(struct ast_channel *chan, const char *cmd, char *data, struct ast_str **buf, ssize_t len)
+{
+	enum file_format newline_format = file2format(data);
+	ast_str_set(buf, len, "%c", newline_format == FF_UNIX ? 'u' : newline_format == FF_DOS ? 'd' : newline_format == FF_MAC ? 'm' : 'x');
+	return 0;
+}
+
+static int file_read(struct ast_channel *chan, const char *cmd, char *data, struct ast_str **buf, ssize_t len)
+{
+	FILE *ff;
+	int64_t offset = 0, length = LLONG_MAX;
+	enum file_format format = FF_UNKNOWN;
+	char fbuf[4096];
+	int64_t flength, i; /* iterator needs to be signed, so it can go negative and terminate the loop */
+	int64_t offset_offset = -1, length_offset = -1;
+	char dos_state = 0;
+	size_t readlen;
 	AST_DECLARE_APP_ARGS(args,
 		AST_APP_ARG(filename);
 		AST_APP_ARG(offset);
 		AST_APP_ARG(length);
+		AST_APP_ARG(options);
+		AST_APP_ARG(fileformat);
 	);
-	int offset = 0, length, res = 0;
-	char *contents;
-	size_t contents_len;
 
 	AST_STANDARD_APP_ARGS(args, data);
+
 	if (args.argc > 1) {
-		offset = atoi(args.offset);
+		sscanf(args.offset, "%" SCNd64, &offset);
 	}
-
 	if (args.argc > 2) {
-		/* The +1/-1 in this code section is to accomodate for the terminating NULL. */
-		if ((length = atoi(args.length) + 1) > len) {
-			ast_log(LOG_WARNING, "Length %d is greater than the max (%d).  Truncating output.\n", length - 1, (int)len - 1);
-			length = len;
+		sscanf(args.length, "%" SCNd64, &length);
+	}
+
+	if (args.argc < 4 || !strchr(args.options, 'l')) {
+		/* Character-based mode */
+		off_t off_i;
+
+		if (!(ff = fopen(args.filename, "r"))) {
+			ast_log(LOG_WARNING, "Cannot open file '%s' for reading: %s\n", args.filename, strerror(errno));
+			return 0;
 		}
-	} else {
-		length = len;
+
+		fseeko(ff, 0, SEEK_END);
+		flength = ftello(ff);
+
+		if (offset < 0) {
+			fseeko(ff, offset, SEEK_END);
+			offset = ftello(ff);
+		}
+		if (length < 0) {
+			fseeko(ff, length, SEEK_END);
+			if ((length = ftello(ff)) - offset < 0) {
+				/* Eliminates all results */
+				return -1;
+			}
+		} else if (length == LLONG_MAX) {
+			fseeko(ff, 0, SEEK_END);
+			length = ftello(ff);
+		}
+
+		ast_str_reset(*buf);
+
+		fseeko(ff, offset, SEEK_SET);
+		for (off_i = ftello(ff); off_i < flength && off_i < offset + length; off_i += sizeof(fbuf)) {
+			/* Calculate if we need to retrieve just a portion of the file in memory */
+			size_t toappend = sizeof(fbuf);
+
+			if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf) && !feof(ff)) {
+				ast_log(LOG_ERROR, "Short read?!!\n");
+				break;
+			}
+
+			/* Don't go past the length requested */
+			if (off_i + toappend > offset + length) {
+				toappend = length - off_i;
+			}
+
+			ast_str_append_substr(buf, len, fbuf, toappend);
+		}
+		return 0;
 	}
 
-	if (!(contents = ast_read_textfile(args.filename))) {
+	/* Line-based read */
+	if (args.argc == 5) {
+		if (tolower(args.fileformat[0]) == 'd') {
+			format = FF_DOS;
+		} else if (tolower(args.fileformat[0]) == 'm') {
+			format = FF_MAC;
+		} else if (tolower(args.fileformat[0]) == 'u') {
+			format = FF_UNIX;
+		}
+	}
+
+	if (format == FF_UNKNOWN) {
+		if ((format = file2format(args.filename)) == FF_UNKNOWN) {
+			ast_log(LOG_WARNING, "'%s' is not a line-based file\n", args.filename);
+			return -1;
+		}
+	}
+
+	if (offset < 0 && length <= offset) {
+		/* Length eliminates all content */
 		return -1;
+	} else if (offset == 0) {
+		offset_offset = 0;
 	}
 
-	do {
-		contents_len = strlen(contents);
-		if (offset > contents_len) {
-			res = -1;
-			break;
+	if (!(ff = fopen(args.filename, "r"))) {
+		ast_log(LOG_ERROR, "Cannot open '%s': %s\n", args.filename, strerror(errno));
+		return -1;
+	}
+
+	if (fseek(ff, 0, SEEK_END)) {
+		ast_log(LOG_ERROR, "Cannot seek to end of file '%s': %s\n", args.filename, strerror(errno));
+		fclose(ff);
+		return -1;
+	}
+	flength = ftello(ff);
+
+	if (length == LLONG_MAX) {
+		length_offset = flength;
+	}
+
+	/* For negative offset and/or negative length */
+	if (offset < 0 || length < 0) {
+		int64_t count = 0;
+		/* Start with an even multiple of fbuf, so at the end of reading with a
+		 * 0 offset, we don't try to go past the beginning of the file. */
+		for (i = (flength / sizeof(fbuf)) * sizeof(fbuf); i >= 0; i -= sizeof(fbuf)) {
+			size_t end;
+			char *pos;
+			if (fseeko(ff, i, SEEK_SET)) {
+				ast_log(LOG_ERROR, "Cannot seek to offset %" PRId64 ": %s\n", i, strerror(errno));
+			}
+			end = fread(fbuf, 1, sizeof(fbuf), ff);
+			for (pos = end < sizeof(fbuf) ? fbuf + end - 1 : fbuf + sizeof(fbuf) - 1; pos > fbuf - 1; pos--) {
+				LINE_COUNTER(pos, format, count);
+
+				if (length < 0 && count * -1 == length) {
+					length_offset = i + (pos - fbuf);
+				} else if (offset < 0 && count * -1 == (offset - 1)) {
+					/* Found our initial offset.  We're done with reverse motion! */
+					if (format == FF_DOS) {
+						offset_offset = i + (pos - fbuf) + 2;
+					} else {
+						offset_offset = i + (pos - fbuf) + 1;
+					}
+					break;
+				}
+			}
+			if ((offset < 0 && offset_offset >= 0) || (offset >= 0 && length_offset >= 0)) {
+				break;
+			}
 		}
+		/* We're at the beginning, and the negative offset indicates the exact number of lines in the file */
+		if (offset < 0 && offset_offset < 0 && offset == count * -1) {
+			offset_offset = 0;
+		}
+	}
 
-		if (offset >= 0) {
-			if (length < 0) {
-				if (contents_len - offset + length < 0) {
-					/* Nothing left after trimming */
-					res = -1;
+	/* Positve line offset */
+	if (offset > 0) {
+		int64_t count = 0;
+		fseek(ff, 0, SEEK_SET);
+		for (i = 0; i < flength; i += sizeof(fbuf)) {
+			char *pos;
+			if (i + sizeof(fbuf) <= flength) {
+				/* Don't let previous values influence current counts, due to short reads */
+				memset(fbuf, 0, sizeof(fbuf));
+			}
+			if (fread(fbuf, 1, sizeof(fbuf), ff) && !feof(ff)) {
+				ast_log(LOG_ERROR, "Short read?!!\n");
+				fclose(ff);
+				return -1;
+			}
+			for (pos = fbuf; pos < fbuf + sizeof(fbuf); pos++) {
+				LINE_COUNTER(pos, format, count);
+
+				if (count == offset) {
+					offset_offset = i + (pos - fbuf) + 1;
 					break;
 				}
-				ast_copy_string(buf, &contents[offset], contents_len + length);
-			} else {
-				ast_copy_string(buf, &contents[offset], length);
+			}
+			if (offset_offset >= 0) {
+				break;
+			}
+		}
+	}
+
+	if (offset_offset < 0) {
+		ast_log(LOG_ERROR, "Offset '%s' refers to before the beginning of the file!\n", args.offset);
+		fclose(ff);
+		return -1;
+	}
+
+	ast_str_reset(*buf);
+	if (fseeko(ff, offset_offset, SEEK_SET)) {
+		ast_log(LOG_ERROR, "fseeko failed: %s\n", strerror(errno));
+	}
+
+	/* If we have both offset_offset and length_offset, then grabbing the
+	 * buffer is simply a matter of just retrieving the file and adding it
+	 * to buf.  Otherwise, we need to run byte-by-byte forward until the
+	 * length is complete. */
+	if (length_offset >= 0) {
+		ast_debug(3, "offset=%" PRId64 ", length=%" PRId64 ", offset_offset=%" PRId64 ", length_offset=%" PRId64 "\n", offset, length, offset_offset, length_offset);
+		for (i = offset_offset; i < length_offset; i += sizeof(fbuf)) {
+			if (fread(fbuf, 1, i + sizeof(fbuf) > flength ? flength - i : sizeof(fbuf), ff) < (i + sizeof(fbuf) > flength ? flength - i : sizeof(fbuf))) {
+				ast_log(LOG_ERROR, "Short read?!!\n");
+			}
+			ast_debug(3, "Appending first %" PRId64" bytes of fbuf=%s\n", i + sizeof(fbuf) > length_offset ? length_offset - i : sizeof(fbuf), fbuf);
+			ast_str_append_substr(buf, len, fbuf, i + sizeof(fbuf) > length_offset ? length_offset - i : sizeof(fbuf));
+		}
+	} else if (length == 0) {
+		/* Nothing to do */
+	} else {
+		/* Positive line offset */
+		int64_t current_length = 0;
+		char dos_state = 0;
+		ast_debug(3, "offset=%" PRId64 ", length=%" PRId64 ", offset_offset=%" PRId64 ", length_offset=%" PRId64 "\n", offset, length, offset_offset, length_offset);
+		for (i = offset_offset; i < flength; i += sizeof(fbuf)) {
+			char *pos;
+			if ((readlen = fread(fbuf, 1, sizeof(fbuf), ff)) < sizeof(fbuf) && !feof(ff)) {
+				ast_log(LOG_ERROR, "Short read?!!\n");
+			}
+			for (pos = fbuf; pos < fbuf + sizeof(fbuf); pos++) {
+				LINE_COUNTER(pos, format, current_length);
+
+				if (current_length == length) {
+					length_offset = i + (pos - fbuf) + 1;
+					break;
+				}
+			}
+			ast_debug(3, "length_offset=%" PRId64 ", length_offset - i=%" PRId64 "\n", length_offset, length_offset - i);
+			ast_str_append_substr(buf, len, fbuf, length_offset >= 0 ? length_offset - i : flength > i + sizeof(fbuf)) ? sizeof(fbuf) : flength - i;
+
+			if (length_offset >= 0) {
+				break;
+			}
+		}
+	}
+
+	return 0;
+}
+
+const char *format2term(enum file_format f) __attribute__((const));
+const char *format2term(enum file_format f)
+{
+	const char *term[] = { "", "\n", "\r\n", "\r" };
+	return term[f + 1];
+}
+
+static int file_write(struct ast_channel *chan, const char *cmd, char *data, const char *value)
+{
+	AST_DECLARE_APP_ARGS(args,
+		AST_APP_ARG(filename);
+		AST_APP_ARG(offset);
+		AST_APP_ARG(length);
+		AST_APP_ARG(options);
+		AST_APP_ARG(format);
+	);
+	int64_t offset = 0, length = LLONG_MAX;
+	off_t flength, vlength;
+	size_t foplen;
+	FILE *ff;
+
+	AST_STANDARD_APP_ARGS(args, data);
+
+	if (args.argc > 1) {
+		sscanf(args.offset, "%" SCNd64, &offset);
+	}
+	if (args.argc > 2) {
+		sscanf(args.length, "%" SCNd64, &length);
+	}
+
+	vlength = strlen(value);
+
+	if (args.argc < 4 || !strchr(args.options, 'l')) {
+		/* Character-based mode */
+
+		if (args.argc > 3 && strchr(args.options, 'a')) {
+			/* Append mode */
+			if (!(ff = fopen(args.filename, "a"))) {
+				ast_log(LOG_WARNING, "Cannot open file '%s' for appending: %s\n", args.filename, strerror(errno));
+				return 0;
+			}
+			if (fwrite(value, 1, vlength, ff) < vlength) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			}
+			fclose(ff);
+			return 0;
+		} else if (offset == 0 && length == LLONG_MAX) {
+			if (!(ff = fopen(args.filename, "w"))) {
+				ast_log(LOG_WARNING, "Cannot open file '%s' for writing: %s\n", args.filename, strerror(errno));
+				return 0;
+			}
+			if (fwrite(value, 1, vlength, ff) < vlength) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			}
+			fclose(ff);
+			return 0;
+		}
+
+		if (!(ff = fopen(args.filename, "r+"))) {
+			ast_log(LOG_WARNING, "Cannot open file '%s' for modification: %s\n", args.filename, strerror(errno));
+			return 0;
+		}
+		fseeko(ff, 0, SEEK_END);
+		flength = ftello(ff);
+
+		if (offset < 0) {
+			if (fseeko(ff, offset, SEEK_END)) {
+				ast_log(LOG_ERROR, "Cannot seek to offset: %s\n", strerror(errno));
+			}
+			offset = ftello(ff);
+		}
+
+		if (length < 0) {
+			length = flength - offset + length;
+			if (length < 0) {
+				ast_log(LOG_ERROR, "Length '%s' exceeds the file length.  No data will be written.\n", args.length);
+				fclose(ff);
+				return -1;
+			}
+		}
+
+		fseeko(ff, offset, SEEK_SET);
+
+		ast_debug(3, "offset=%s/%" PRId64 ", length=%s/%" PRId64 ", vlength=%" PRId64 ", flength=%" PRId64 "\n",
+			args.offset, offset, args.length, length, vlength, flength);
+
+		if (length == vlength) {
+			/* Simplest case, a straight replace */
+			if (fwrite(value, 1, vlength, ff) < vlength) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			}
+			fclose(ff);
+		} else if (length == LLONG_MAX) {
+			/* Simple truncation */
+			if (fwrite(value, 1, vlength, ff) < vlength) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			}
+			fclose(ff);
+			if (truncate(args.filename, offset + vlength)) {
+				ast_log(LOG_ERROR, "Unable to truncate the file: %s\n", strerror(errno));
+			}
+		} else if (length > vlength) {
+			/* More complex -- need to close a gap */
+			char fbuf[4096];
+			off_t cur;
+			if (fwrite(value, 1, vlength, ff) < vlength) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			}
+			fseeko(ff, length - vlength, SEEK_CUR);
+			while ((cur = ftello(ff)) < flength) {
+				if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf) && !feof(ff)) {
+					ast_log(LOG_ERROR, "Short read?!!\n");
+				}
+				fseeko(ff, cur + vlength - length, SEEK_SET);
+				if (fwrite(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf)) {
+					ast_log(LOG_ERROR, "Short write?!!\n");
+				}
+			}
+			fclose(ff);
+			if (truncate(args.filename, flength - (length - vlength))) {
+				ast_log(LOG_ERROR, "Unable to truncate the file: %s\n", strerror(errno));
 			}
 		} else {
-			if (offset * -1 > contents_len) {
-				ast_log(LOG_WARNING, "Offset is larger than the file size.\n");
-				offset = contents_len * -1;
+			/* Most complex -- need to open a gap */
+			char fbuf[4096];
+			off_t lastwritten = flength + vlength - length;
+
+			/* Start reading exactly the buffer size back from the end. */
+			fseeko(ff, flength - sizeof(fbuf), SEEK_SET);
+			while (offset < ftello(ff)) {
+				if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf)) {
+					ast_log(LOG_ERROR, "Short read?!!\n");
+					fclose(ff);
+					return -1;
+				}
+				/* Since the read moved our file ptr forward, we reverse, but
+				 * seek an offset equal to the amount we want to extend the
+				 * file by */
+				fseeko(ff, vlength - length - sizeof(fbuf), SEEK_CUR);
+
+				/* Note the location of this buffer -- we must not overwrite this position. */
+				lastwritten = ftello(ff);
+
+				if (fwrite(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf)) {
+					ast_log(LOG_ERROR, "Short write?!!\n");
+					fclose(ff);
+					return -1;
+				}
+
+				if (lastwritten < offset + sizeof(fbuf)) {
+					break;
+				}
+				/* Our file pointer is now either pointing to the end of the
+				 * file (new position) or a multiple of the fbuf size back from
+				 * that point.  Move back to where we want to start reading
+				 * again.  We never actually try to read beyond the end of the
+				 * file, so we don't have do deal with short reads, as we would
+				 * when we're shortening the file. */
+				fseeko(ff, 2 * sizeof(fbuf) + vlength - length, SEEK_CUR);
+			}
+
+			/* Last part of the file that we need to preserve */
+			if (fseeko(ff, offset + length, SEEK_SET)) {
+				ast_log(LOG_WARNING, "Unable to seek to %" PRId64 " + %" PRId64 " != %" PRId64 "?)\n", offset, length, ftello(ff));
+			}
+
+			/* Doesn't matter how much we read -- just need to restrict the write */
+			ast_debug(1, "Reading at %" PRId64 "\n", ftello(ff));
+			if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf) && !feof(ff)) {
+				ast_log(LOG_ERROR, "Short read?!!\n");
+			}
+			fseek(ff, offset, SEEK_SET);
+			/* Write out the value, then write just up until where we last moved some data */
+			if (fwrite(value, 1, vlength, ff) < vlength) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			} else if (fwrite(fbuf, 1, (foplen = lastwritten - ftello(ff)), ff) < foplen) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
 			}
-			ast_copy_string(buf, &contents[contents_len + offset], length);
+			fclose(ff);
 		}
-	} while (0);
+	} else {
+		enum file_format newline_format = FF_UNKNOWN;
 
-	ast_free(contents);
+		/* Line mode */
+		if (args.argc == 5) {
+			if (tolower(args.format[0]) == 'u') {
+				newline_format = FF_UNIX;
+			} else if (tolower(args.format[0]) == 'm') {
+				newline_format = FF_MAC;
+			} else if (tolower(args.format[0]) == 'd') {
+				newline_format = FF_DOS;
+			}
+		}
+		if (newline_format == FF_UNKNOWN && (newline_format = file2format(args.filename)) == FF_UNKNOWN) {
+			ast_log(LOG_ERROR, "File '%s' not in line format\n", args.filename);
+			return -1;
+		}
 
-	return res;
+		if (strchr(args.options, 'a')) {
+			/* Append to file */
+			if (!(ff = fopen(args.filename, "a"))) {
+				ast_log(LOG_ERROR, "Unable to open '%s' for appending: %s\n", args.filename, strerror(errno));
+				return -1;
+			}
+			if (fwrite(value, 1, vlength, ff) < vlength) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			} else if (!strchr(args.options, 'd') && fwrite(format2term(newline_format), 1, strlen(format2term(newline_format)), ff) < strlen(format2term(newline_format))) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			}
+			fclose(ff);
+		} else if (offset == 0 && length == LLONG_MAX) {
+			/* Overwrite file */
+			off_t truncsize;
+			if (!(ff = fopen(args.filename, "w"))) {
+				ast_log(LOG_ERROR, "Unable to open '%s' for writing: %s\n", args.filename, strerror(errno));
+				return -1;
+			}
+			if (fwrite(value, 1, vlength, ff) < vlength) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			} else if (!strchr(args.options, 'd') && fwrite(format2term(newline_format), 1, strlen(format2term(newline_format)), ff) < strlen(format2term(newline_format))) {
+				ast_log(LOG_ERROR, "Short write?!!\n");
+			}
+			truncsize = ftello(ff);
+			fclose(ff);
+			if (truncate(args.filename, truncsize)) {
+				ast_log(LOG_ERROR, "Unable to truncate file: %s\n", strerror(errno));
+			}
+		} else {
+			int64_t offset_offset = (offset == 0 ? 0 : -1), length_offset = -1, flength, i, current_length = 0;
+			char dos_state = 0, fbuf[4096];
+
+			if (offset < 0 && length < offset) {
+				/* Nonsense! */
+				ast_log(LOG_ERROR, "Length cannot specify a position prior to the offset\n");
+				return -1;
+			}
+
+			if (!(ff = fopen(args.filename, "r+"))) {
+				ast_log(LOG_ERROR, "Cannot open '%s' for modification: %s\n", args.filename, strerror(errno));
+				return -1;
+			}
+
+			if (fseek(ff, 0, SEEK_END)) {
+				ast_log(LOG_ERROR, "Cannot seek to end of file '%s': %s\n", args.filename, strerror(errno));
+				fclose(ff);
+				return -1;
+			}
+			flength = ftello(ff);
+
+			/* For negative offset and/or negative length */
+			if (offset < 0 || length < 0) {
+				int64_t count = 0;
+				for (i = (flength / sizeof(fbuf)) * sizeof(fbuf); i >= 0; i -= sizeof(fbuf)) {
+					char *pos;
+					if (fseeko(ff, i, SEEK_SET)) {
+						ast_log(LOG_ERROR, "Cannot seek to offset %" PRId64 ": %s\n", i, strerror(errno));
+					}
+					if (i + sizeof(fbuf) >= flength) {
+						memset(fbuf, 0, sizeof(fbuf));
+					}
+					if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf) && !feof(ff)) {
+						ast_log(LOG_ERROR, "Short read: %s\n", strerror(errno));
+						fclose(ff);
+						return -1;
+					}
+					for (pos = fbuf + sizeof(fbuf) - 1; pos > fbuf - 1; pos--) {
+						LINE_COUNTER(pos, newline_format, count);
+
+						if (length < 0 && count * -1 == length) {
+							length_offset = i + (pos - fbuf);
+						} else if (offset < 0 && count * -1 == (offset - 1)) {
+							/* Found our initial offset.  We're done with reverse motion! */
+							if (newline_format == FF_DOS) {
+								offset_offset = i + (pos - fbuf) + 2;
+							} else {
+								offset_offset = i + (pos - fbuf) + 1;
+							}
+							break;
+						}
+					}
+					if ((offset < 0 && offset_offset >= 0) || (offset >= 0 && length_offset >= 0)) {
+						break;
+					}
+				}
+				/* We're at the beginning, and the negative offset indicates the exact number of lines in the file */
+				if (offset < 0 && offset_offset < 0 && offset == count * -1) {
+					offset_offset = 0;
+				}
+			}
+
+			/* Positve line offset */
+			if (offset > 0) {
+				int64_t count = 0;
+				fseek(ff, 0, SEEK_SET);
+				for (i = 0; i < flength; i += sizeof(fbuf)) {
+					char *pos;
+					if (i + sizeof(fbuf) >= flength) {
+						memset(fbuf, 0, sizeof(fbuf));
+					}
+					if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf) && !feof(ff)) {
+						ast_log(LOG_ERROR, "Short read?!!\n");
+						fclose(ff);
+						return -1;
+					}
+					for (pos = fbuf; pos < fbuf + sizeof(fbuf); pos++) {
+						LINE_COUNTER(pos, newline_format, count);
+
+						if (count == offset) {
+							offset_offset = i + (pos - fbuf) + 1;
+							break;
+						}
+					}
+					if (offset_offset >= 0) {
+						break;
+					}
+				}
+			}
+
+			if (offset_offset < 0) {
+				ast_log(LOG_ERROR, "Offset '%s' refers to before the beginning of the file!\n", args.offset);
+				fclose(ff);
+				return -1;
+			}
+
+			if (length == 0) {
+				length_offset = offset_offset;
+			} else if (length == LLONG_MAX) {
+				length_offset = flength;
+			}
+
+			/* Positive line length */
+			if (length_offset < 0) {
+				fseeko(ff, offset_offset, SEEK_SET);
+				for (i = offset_offset; i < flength; i += sizeof(fbuf)) {
+					char *pos;
+					if (i + sizeof(fbuf) >= flength) {
+						memset(fbuf, 0, sizeof(fbuf));
+					}
+					if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf) && !feof(ff)) {
+						ast_log(LOG_ERROR, "Short read?!!\n");
+						fclose(ff);
+						return -1;
+					}
+					for (pos = fbuf; pos < fbuf + sizeof(fbuf); pos++) {
+						LINE_COUNTER(pos, newline_format, current_length);
+
+						if (current_length == length) {
+							length_offset = i + (pos - fbuf) + 1;
+							break;
+						}
+					}
+					if (length_offset >= 0) {
+						break;
+					}
+				}
+				if (length_offset < 0) {
+					/* Exceeds length of file */
+					ast_debug(3, "Exceeds length of file? length=%" PRId64 ", count=%" PRId64 ", flength=%" PRId64 "\n", length, current_length, flength);
+					length_offset = flength;
+				}
+			}
+
+			/* Have offset_offset and length_offset now */
+			if (length_offset - offset_offset == vlength + (strchr(args.options, 'd') ? 0 : strlen(format2term(newline_format)))) {
+				/* Simple case - replacement of text inline */
+				fseeko(ff, offset_offset, SEEK_SET);
+				if (fwrite(value, 1, vlength, ff) < vlength) {
+					ast_log(LOG_ERROR, "Short write?!!\n");
+				} else if (!strchr(args.options, 'd') && fwrite(format2term(newline_format), 1, strlen(format2term(newline_format)), ff) < strlen(format2term(newline_format))) {
+					ast_log(LOG_ERROR, "Short write?!!\n");
+				}
+				fclose(ff);
+			} else if (length_offset - offset_offset > vlength + (strchr(args.options, 'd') ? 0 : strlen(format2term(newline_format)))) {
+				/* More complex case - need to shorten file */
+				off_t cur;
+				int64_t length_length = length_offset - offset_offset;
+				size_t vlen = vlength + (strchr(args.options, 'd') ? 0 : strlen(format2term(newline_format)));
+
+				ast_debug(3, "offset=%s/%" PRId64 ", length=%s/%" PRId64 " (%" PRId64 "), vlength=%" PRId64 ", flength=%" PRId64 "\n",
+					args.offset, offset_offset, args.length, length_offset, length_length, vlength, flength);
+
+				fseeko(ff, offset_offset, SEEK_SET);
+				if (fwrite(value, 1, vlength, ff) < vlength) {
+					ast_log(LOG_ERROR, "Short write?!!\n");
+					fclose(ff);
+					return -1;
+				} else if (!strchr(args.options, 'd') && fwrite(format2term(newline_format), 1, vlen - vlength, ff) < vlen - vlength) {
+					ast_log(LOG_ERROR, "Short write?!!\n");
+					fclose(ff);
+					return -1;
+				}
+				while ((cur = ftello(ff)) < flength) {
+					fseeko(ff, length_length - vlen, SEEK_CUR);
+					if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf) && !feof(ff)) {
+						ast_log(LOG_ERROR, "Short read?!!\n");
+						fclose(ff);
+						return -1;
+					}
+					/* Seek to where we last stopped writing */
+					fseeko(ff, cur, SEEK_SET);
+					if (fwrite(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf)) {
+						ast_log(LOG_ERROR, "Short write?!!\n");
+						fclose(ff);
+						return -1;
+					}
+				}
+				fclose(ff);
+				if (truncate(args.filename, flength - (length_length - vlen))) {
+					ast_log(LOG_ERROR, "Truncation of file failed: %s\n", strerror(errno));
+				}
+			} else {
+				/* Most complex case - need to lengthen file */
+				size_t vlen = vlength + (strchr(args.options, 'd') ? 0 : strlen(format2term(newline_format)));
+				int64_t origlen = length_offset - offset_offset;
+				off_t lastwritten = flength + vlen - origlen;
+
+				ast_debug(3, "offset=%s/%" PRId64 ", length=%s/%" PRId64 ", vlength=%" PRId64 ", flength=%" PRId64 "\n",
+					args.offset, offset_offset, args.length, length_offset, vlength, flength);
+
+				fseeko(ff, flength - sizeof(fbuf), SEEK_SET);
+				while (offset_offset + sizeof(fbuf) < ftello(ff)) {
+					if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf)) {
+						ast_log(LOG_ERROR, "Short read?!!\n");
+						fclose(ff);
+						return -1;
+					}
+					fseeko(ff, sizeof(fbuf) - vlen - origlen, SEEK_CUR);
+					if (fwrite(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf)) {
+						ast_log(LOG_ERROR, "Short write?!!\n");
+						fclose(ff);
+						return -1;
+					}
+					if ((lastwritten = ftello(ff) - sizeof(fbuf)) < offset_offset + sizeof(fbuf)) {
+						break;
+					}
+					fseeko(ff, 2 * sizeof(fbuf) + vlen - origlen, SEEK_CUR);
+				}
+				fseek(ff, length_offset, SEEK_SET);
+				if (fread(fbuf, 1, sizeof(fbuf), ff) < sizeof(fbuf) && !feof(ff)) {
+					ast_log(LOG_ERROR, "Short read?!!\n");
+					fclose(ff);
+					return -1;
+				}
+				fseek(ff, offset_offset, SEEK_SET);
+				if (fwrite(value, 1, vlength, ff) < vlength) {
+					ast_log(LOG_ERROR, "Short write?!!\n");
+					fclose(ff);
+					return -1;
+				} else if (!strchr(args.options, 'd') && fwrite(format2term(newline_format), 1, strlen(format2term(newline_format)), ff) < strlen(format2term(newline_format))) {
+					ast_log(LOG_ERROR, "Short write?!!\n");
+					fclose(ff);
+					return -1;
+				} else if (fwrite(fbuf, 1, (foplen = lastwritten - ftello(ff)), ff) < foplen) {
+					ast_log(LOG_ERROR, "Short write?!!\n");
+				}
+				fclose(ff);
+			}
+		}
+	}
+
+	return 0;
 }
 
 static struct ast_custom_function env_function = {
@@ -237,12 +1178,20 @@ static struct ast_custom_function stat_function = {
 
 static struct ast_custom_function file_function = {
 	.name = "FILE",
-	.read = file_read
-	/*
-	 * Some enterprising programmer could probably add write functionality
-	 * to FILE(), although I'm not sure how useful it would be.  Hence why
-	 * it's called FILE and not READFILE (like the app was).
-	 */
+	.read2 = file_read,
+	.write = file_write,
+};
+
+static struct ast_custom_function file_count_line_function = {
+	.name = "FILE_COUNT_LINE",
+	.read2 = file_count_line,
+	.read_max = 12,
+};
+
+static struct ast_custom_function file_format_function = {
+	.name = "FILE_FORMAT",
+	.read2 = file_format,
+	.read_max = 2,
 };
 
 static int unload_module(void)
@@ -252,6 +1201,8 @@ static int unload_module(void)
 	res |= ast_custom_function_unregister(&env_function);
 	res |= ast_custom_function_unregister(&stat_function);
 	res |= ast_custom_function_unregister(&file_function);
+	res |= ast_custom_function_unregister(&file_count_line_function);
+	res |= ast_custom_function_unregister(&file_format_function);
 
 	return res;
 }
@@ -263,6 +1214,8 @@ static int load_module(void)
 	res |= ast_custom_function_register(&env_function);
 	res |= ast_custom_function_register(&stat_function);
 	res |= ast_custom_function_register(&file_function);
+	res |= ast_custom_function_register(&file_count_line_function);
+	res |= ast_custom_function_register(&file_format_function);
 
 	return res;
 }