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/*
* Copyright (c) 2015, Intel Corporation
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*
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/*
* Hyperscan example program 1: simplegrep
*
* This is a simple example of Hyperscan's most basic functionality: it will
* search a given input file for a pattern supplied as a command-line argument.
* It is intended to demonstrate correct usage of the hs_compile and hs_scan
* functions of Hyperscan.
*
* Patterns are scanned in 'DOTALL' mode, which is equivalent to PCRE's '/s'
* modifier. This behaviour can be changed by modifying the "flags" argument to
* hs_compile.
*
* Build instructions:
*
* gcc -o simplegrep simplegrep.c $(pkg-config --cflags --libs libhs)
*
* Usage:
*
* ./simplegrep <pattern> <input file>
*
* Example:
*
* ./simplegrep int simplegrep.c
*
*/
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <hs.h>
/**
* This is the function that will be called for each match that occurs. @a ctx
* is to allow you to have some application-specific state that you will get
* access to for each match. In our simple example we're just going to use it
* to pass in the pattern that was being searched for so we can print it out.
*/
static int eventHandler(unsigned int id, unsigned long long from,
unsigned long long to, unsigned int flags, void *ctx) {
printf("Match for pattern \"%s\" at offset %llu\n", (char *)ctx, to);
return 0;
}
/**
* Fill a data buffer from the given filename, returning it and filling @a
* length with its length. Returns NULL on failure.
*/
static char *readInputData(const char *inputFN, unsigned int *length) {
FILE *f = fopen(inputFN, "rb");
if (!f) {
fprintf(stderr, "ERROR: unable to open file \"%s\": %s\n", inputFN,
strerror(errno));
return NULL;
}
/* We use fseek/ftell to get our data length, in order to keep this example
* code as portable as possible. */
if (fseek(f, 0, SEEK_END) != 0) {
fprintf(stderr, "ERROR: unable to seek file \"%s\": %s\n", inputFN,
strerror(errno));
fclose(f);
return NULL;
}
long dataLen = ftell(f);
if (dataLen < 0) {
fprintf(stderr, "ERROR: ftell() failed: %s\n", strerror(errno));
fclose(f);
return NULL;
}
if (fseek(f, 0, SEEK_SET) != 0) {
fprintf(stderr, "ERROR: unable to seek file \"%s\": %s\n", inputFN,
strerror(errno));
fclose(f);
return NULL;
}
/* Hyperscan's hs_scan function accepts length as an unsigned int, so we
* limit the size of our buffer appropriately. */
if ((unsigned long)dataLen > UINT_MAX) {
dataLen = UINT_MAX;
printf("WARNING: clipping data to %ld bytes\n", dataLen);
} else if (dataLen == 0) {
fprintf(stderr, "ERROR: input file \"%s\" is empty\n", inputFN);
fclose(f);
return NULL;
}
char *inputData = malloc(dataLen);
if (!inputData) {
fprintf(stderr, "ERROR: unable to malloc %ld bytes\n", dataLen);
fclose(f);
return NULL;
}
char *p = inputData;
size_t bytesLeft = dataLen;
while (bytesLeft) {
size_t bytesRead = fread(p, 1, bytesLeft, f);
bytesLeft -= bytesRead;
p += bytesRead;
if (ferror(f) != 0) {
fprintf(stderr, "ERROR: fread() failed\n");
free(inputData);
fclose(f);
return NULL;
}
}
fclose(f);
*length = (unsigned int)dataLen;
return inputData;
}
int main(int argc, char *argv[]) {
if (argc != 3) {
fprintf(stderr, "Usage: %s <pattern> <input file>\n", argv[0]);
return -1;
}
char *pattern = argv[1];
char *inputFN = argv[2];
/* First, we attempt to compile the pattern provided on the command line.
* We assume 'DOTALL' semantics, meaning that the '.' meta-character will
* match newline characters. The compiler will analyse the given pattern and
* either return a compiled Hyperscan database, or an error message
* explaining why the pattern didn't compile.
*/
hs_database_t *database;
hs_compile_error_t *compile_err;
if (hs_compile(pattern, HS_FLAG_DOTALL, HS_MODE_BLOCK, NULL, &database,
&compile_err) != HS_SUCCESS) {
fprintf(stderr, "ERROR: Unable to compile pattern \"%s\": %s\n",
pattern, compile_err->message);
hs_free_compile_error(compile_err);
return -1;
}
/* Next, we read the input data file into a buffer. */
unsigned int length;
char *inputData = readInputData(inputFN, &length);
if (!inputData) {
hs_free_database(database);
return -1;
}
/* Finally, we issue a call to hs_scan, which will search the input buffer
* for the pattern represented in the bytecode. Note that in order to do
* this, scratch space needs to be allocated with the hs_alloc_scratch
* function. In typical usage, you would reuse this scratch space for many
* calls to hs_scan, but as we're only doing one, we'll be allocating it
* and deallocating it as soon as our matching is done.
*
* When matches occur, the specified callback function (eventHandler in
* this file) will be called. Note that although it is reminiscent of
* asynchronous APIs, Hyperscan operates synchronously: all matches will be
* found, and all callbacks issued, *before* hs_scan returns.
*
* In this example, we provide the input pattern as the context pointer so
* that the callback is able to print out the pattern that matched on each
* match event.
*/
hs_scratch_t *scratch = NULL;
if (hs_alloc_scratch(database, &scratch) != HS_SUCCESS) {
fprintf(stderr, "ERROR: Unable to allocate scratch space. Exiting.\n");
free(inputData);
hs_free_database(database);
return -1;
}
printf("Scanning %u bytes with Hyperscan\n", length);
if (hs_scan(database, inputData, length, 0, scratch, eventHandler,
pattern) != HS_SUCCESS) {
fprintf(stderr, "ERROR: Unable to scan input buffer. Exiting.\n");
hs_free_scratch(scratch);
free(inputData);
hs_free_database(database);
return -1;
}
/* Scanning is complete, any matches have been handled, so now we just
* clean up and exit.
*/
hs_free_scratch(scratch);
free(inputData);
hs_free_database(database);
return 0;
}
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