/* * netsniff-ng - the packet sniffing beast * By Daniel Borkmann <daniel@netsniff-ng.org> * Copyright 2011 Daniel Borkmann <dborkma@tik.ee.ethz.ch>, * Swiss federal institute of technology (ETH Zurich) * Subject to the GPL, version 2. */ /* yaac-func-prefix: yy */ %{ #include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <signal.h> #include <stdint.h> #include <errno.h> #include <libgen.h> #include "bpf.h" #include "xmalloc.h" #include "bpf_parser.tab.h" #include "built_in.h" #include "die.h" #include "xutils.h" #define MAX_INSTRUCTIONS 4096 int compile_filter(char *file, int verbose, int bypass, int format, bool invoke_cpp); static int curr_instr = 0; static struct sock_filter out[MAX_INSTRUCTIONS]; static char *labels[MAX_INSTRUCTIONS]; static char *labels_jt[MAX_INSTRUCTIONS]; static char *labels_jf[MAX_INSTRUCTIONS]; static char *labels_k[MAX_INSTRUCTIONS]; #define YYERROR_VERBOSE 0 #define YYDEBUG 0 #define YYENABLE_NLS 1 #define YYLTYPE_IS_TRIVIAL 1 #define ENABLE_NLS 1 extern FILE *yyin; extern int yylex(void); extern void yyerror(const char *); extern int yylineno; extern char *yytext; static inline void check_max_instr(void) { if (curr_instr >= MAX_INSTRUCTIONS) panic("Exceeded maximal number of instructions!\n"); } static inline void set_curr_instr(uint16_t code, uint8_t jt, uint8_t jf, uint32_t k) { check_max_instr(); out[curr_instr].code = code; out[curr_instr].jt = jt; out[curr_instr].jf = jf; out[curr_instr].k = k; curr_instr++; } static inline void set_curr_label(char *label) { check_max_instr(); labels[curr_instr] = label; } #define JTL 1 #define JFL 2 #define JKL 3 static inline void set_jmp_label(char *label, int which) { check_max_instr(); switch (which) { case JTL: labels_jt[curr_instr] = label; break; case JFL: labels_jf[curr_instr] = label; break; case JKL: labels_k[curr_instr] = label; break; default: bug(); } } static int find_intr_offset_or_panic(char *label_to_search) { int i, max = curr_instr, ret = -ENOENT; bug_on(!label_to_search); for (i = 0; i < max; ++i) { if (labels[i] != NULL) { /* Both are \0-terminated! */ if (!strcmp(label_to_search, labels[i])) { ret = i; break; } } } if (ret == -ENOENT) panic("No such label!\n"); return ret; } %} %union { char *label; long int number; } %token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE %token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH %token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI %token OP_LDXI %token K_PKT_LEN K_PROTO K_TYPE K_NLATTR K_NLATTR_NEST K_MARK K_QUEUE K_HATYPE %token K_RXHASH K_CPU K_IFIDX K_VLANT K_VLANP K_POFF %token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#' %token number label %type <number> number %type <label> label %% prog : line | prog line ; line : instr | labelled_instr ; labelled_instr : labelled instr ; instr : ldb | ldh | ld | ldi | ldx | ldxi | st | stx | jmp | jeq | jneq | jlt | jle | jgt | jge | jset | add | sub | mul | div | mod | neg | and | or | xor | lsh | rsh | ret | tax | txa ; labelled : label ':' { set_curr_label($1); } ; ldb : OP_LDB '[' 'x' '+' number ']' { set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $5); } | OP_LDB '[' number ']' { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, $3); } | OP_LDB K_PROTO { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_PROTOCOL); } | OP_LDB K_TYPE { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_PKTTYPE); } | OP_LDB K_IFIDX { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_IFINDEX); } | OP_LDB K_NLATTR { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_NLATTR); } | OP_LDB K_NLATTR_NEST { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_NLATTR_NEST); } | OP_LDB K_MARK { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_MARK); } | OP_LDB K_QUEUE { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_QUEUE); } | OP_LDB K_HATYPE { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_HATYPE); } | OP_LDB K_RXHASH { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_RXHASH); } | OP_LDB K_CPU { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_CPU); } | OP_LDB K_VLANT { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_VLAN_TAG); } | OP_LDB K_VLANP { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); } | OP_LDB K_POFF { set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_PAY_OFFSET); } ; ldh : OP_LDH '[' 'x' '+' number ']' { set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $5); } | OP_LDH '[' number ']' { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, $3); } | OP_LDH K_PROTO { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_PROTOCOL); } | OP_LDH K_TYPE { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_PKTTYPE); } | OP_LDH K_IFIDX { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_IFINDEX); } | OP_LDH K_NLATTR { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_NLATTR); } | OP_LDH K_NLATTR_NEST { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_NLATTR_NEST); } | OP_LDH K_MARK { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_MARK); } | OP_LDH K_QUEUE { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_QUEUE); } | OP_LDH K_HATYPE { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_HATYPE); } | OP_LDH K_RXHASH { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_RXHASH); } | OP_LDH K_CPU { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_CPU); } | OP_LDH K_VLANT { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_VLAN_TAG); } | OP_LDH K_VLANP { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); } | OP_LDH K_POFF { set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_PAY_OFFSET); } ; ldi : OP_LDI number { set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $2); } ; ld : OP_LD '#' number { set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); } | OP_LD K_PKT_LEN { set_curr_instr(BPF_LD | BPF_W | BPF_LEN, 0, 0, 0); } | OP_LD K_PROTO { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_PROTOCOL); } | OP_LD K_TYPE { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_PKTTYPE); } | OP_LD K_IFIDX { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_IFINDEX); } | OP_LD K_NLATTR { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_NLATTR); } | OP_LD K_NLATTR_NEST { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_NLATTR_NEST); } | OP_LD K_MARK { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_MARK); } | OP_LD K_QUEUE { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_QUEUE); } | OP_LD K_HATYPE { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_HATYPE); } | OP_LD K_RXHASH { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_RXHASH); } | OP_LD K_CPU { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_CPU); } | OP_LD K_VLANT { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_VLAN_TAG); } | OP_LD K_VLANP { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); } | OP_LD K_POFF { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, SKF_AD_OFF + SKF_AD_PAY_OFFSET); } | OP_LD 'M' '[' number ']' { set_curr_instr(BPF_LD | BPF_MEM, 0, 0, $4); } | OP_LD '[' 'x' '+' number ']' { set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $5); } | OP_LD '[' number ']' { set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, $3); } ; ldxi : OP_LDXI number { set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $2); } ; ldx : OP_LDX '#' number { set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); } | OP_LDX 'M' '[' number ']' { set_curr_instr(BPF_LDX | BPF_MEM, 0, 0, $4); } | OP_LDXB number '*' '(' '[' number ']' '&' number ')' { if ($2 != 4 || $9 != 0xf) { panic("ldxb offset not supported!\n"); } else { set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } } | OP_LDX number '*' '(' '[' number ']' '&' number ')' { if ($2 != 4 || $9 != 0xf) { panic("ldxb offset not supported!\n"); } else { set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } } ; st : OP_ST 'M' '[' number ']' { set_curr_instr(BPF_ST, 0, 0, $4); } ; stx : OP_STX 'M' '[' number ']' { set_curr_instr(BPF_STX, 0, 0, $4); } ; jmp : OP_JMP label { set_jmp_label($2, JKL); set_curr_instr(BPF_JMP | BPF_JA, 0, 0, 0); } ; jeq : OP_JEQ '#' number ',' label ',' label { set_jmp_label($5, JTL); set_jmp_label($7, JFL); set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); } | OP_JEQ 'x' ',' label ',' label { set_jmp_label($4, JTL); set_jmp_label($6, JFL); set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); } | OP_JEQ '#' number ',' label { set_jmp_label($5, JTL); set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); } | OP_JEQ 'x' ',' label { set_jmp_label($4, JTL); set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); } ; jneq : OP_JNEQ '#' number ',' label { set_jmp_label($5, JFL); set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); } | OP_JNEQ 'x' ',' label { set_jmp_label($4, JFL); set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); } ; jlt : OP_JLT '#' number ',' label { set_jmp_label($5, JFL); set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); } | OP_JLT 'x' ',' label { set_jmp_label($4, JFL); set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); } ; jle : OP_JLE '#' number ',' label { set_jmp_label($5, JFL); set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); } | OP_JLE 'x' ',' label { set_jmp_label($4, JFL); set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); } ; jgt : OP_JGT '#' number ',' label ',' label { set_jmp_label($5, JTL); set_jmp_label($7, JFL); set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); } | OP_JGT 'x' ',' label ',' label { set_jmp_label($4, JTL); set_jmp_label($6, JFL); set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); } | OP_JGT '#' number ',' label { set_jmp_label($5, JTL); set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); } | OP_JGT 'x' ',' label { set_jmp_label($4, JTL); set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); } ; jge : OP_JGE '#' number ',' label ',' label { set_jmp_label($5, JTL); set_jmp_label($7, JFL); set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); } | OP_JGE 'x' ',' label ',' label { set_jmp_label($4, JTL); set_jmp_label($6, JFL); set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); } | OP_JGE '#' number ',' label { set_jmp_label($5, JTL); set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); } | OP_JGE 'x' ',' label { set_jmp_label($4, JTL); set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); } ; jset : OP_JSET '#' number ',' label ',' label { set_jmp_label($5, JTL); set_jmp_label($7, JFL); set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); } | OP_JSET 'x' ',' label ',' label { set_jmp_label($4, JTL); set_jmp_label($6, JFL); set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); } | OP_JSET '#' number ',' label { set_jmp_label($5, JTL); set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); } | OP_JSET 'x' ',' label { set_jmp_label($4, JTL); set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); } ; add : OP_ADD '#' number { set_curr_instr(BPF_ALU | BPF_ADD | BPF_K, 0, 0, $3); } | OP_ADD 'x' { set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); } ; sub : OP_SUB '#' number { set_curr_instr(BPF_ALU | BPF_SUB | BPF_K, 0, 0, $3); } | OP_SUB 'x' { set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); } ; mul : OP_MUL '#' number { set_curr_instr(BPF_ALU | BPF_MUL | BPF_K, 0, 0, $3); } | OP_MUL 'x' { set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); } ; div : OP_DIV '#' number { set_curr_instr(BPF_ALU | BPF_DIV | BPF_K, 0, 0, $3); } | OP_DIV 'x' { set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); } ; mod : OP_MOD '#' number { set_curr_instr(BPF_ALU | BPF_MOD | BPF_K, 0, 0, $3); } | OP_MOD 'x' { set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); } ; neg : OP_NEG { set_curr_instr(BPF_ALU | BPF_NEG, 0, 0, 0); } ; and : OP_AND '#' number { set_curr_instr(BPF_ALU | BPF_AND | BPF_K, 0, 0, $3); } | OP_AND 'x' { set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); } ; or : OP_OR '#' number { set_curr_instr(BPF_ALU | BPF_OR | BPF_K, 0, 0, $3); } | OP_OR 'x' { set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); } ; xor : OP_XOR '#' number { set_curr_instr(BPF_ALU | BPF_XOR | BPF_K, 0, 0, $3); } | OP_XOR 'x' { set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); } ; lsh : OP_LSH '#' number { set_curr_instr(BPF_ALU | BPF_LSH | BPF_K, 0, 0, $3); } | OP_LSH 'x' { set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); } ; rsh : OP_RSH '#' number { set_curr_instr(BPF_ALU | BPF_RSH | BPF_K, 0, 0, $3); } | OP_RSH 'x' { set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); } ; ret : OP_RET 'a' { set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); } | OP_RET 'x' { set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); } | OP_RET '#' number { set_curr_instr(BPF_RET | BPF_K, 0, 0, $3); } ; tax : OP_TAX { set_curr_instr(BPF_MISC | BPF_TAX, 0, 0, 0); } ; txa : OP_TXA { set_curr_instr(BPF_MISC | BPF_TXA, 0, 0, 0); } ; %% static void stage_1_inline(void) { yyparse(); } static void stage_2_label_reduce(void) { int i, max = curr_instr, off; /* 1. reduce k jumps */ for (i = 0; i < max; ++i) { if (labels_k[i] != NULL) { off = find_intr_offset_or_panic(labels_k[i]); out[i].k = (uint32_t) (off - i - 1); } } /* 1. reduce jt jumps */ for (i = 0; i < max; ++i) { if (labels_jt[i] != NULL) { off = find_intr_offset_or_panic(labels_jt[i]); out[i].jt = (uint8_t) (off - i -1); } } /* 1. reduce jf jumps */ for (i = 0; i < max; ++i) { if (labels_jf[i] != NULL) { off = find_intr_offset_or_panic(labels_jf[i]); out[i].jf = (uint8_t) (off - i - 1); } } } static void pretty_printer_c(const struct sock_fprog *prog) { int i; for (i = 0; i < prog->len; ++i) { printf("{ 0x%x, %u, %u, 0x%08x },\n", prog->filter[i].code, prog->filter[i].jt, prog->filter[i].jf, prog->filter[i].k); } } static void pretty_printer_xt_bpf(const struct sock_fprog *prog) { int i; printf("%d,", prog->len); for (i = 0; i < prog->len; ++i) { printf("%u %u %u %u,", prog->filter[i].code, prog->filter[i].jt, prog->filter[i].jf, prog->filter[i].k); } fflush(stdout); } static void pretty_printer_tcpdump(const struct sock_fprog *prog) { int i; for (i = 0; i < prog->len; ++i) { printf("%u %u %u %u\n", prog->filter[i].code, prog->filter[i].jt, prog->filter[i].jf, prog->filter[i].k); } } static void pretty_printer(const struct sock_fprog *prog, int format) { switch (format) { case 0: pretty_printer_c(prog); break; case 1: pretty_printer_xt_bpf(prog); break; case 2: pretty_printer_tcpdump(prog); break; default: bug(); } } int compile_filter(char *file, int verbose, int bypass, int format, bool invoke_cpp) { int i; struct sock_fprog res; char tmp_file[128]; memset(tmp_file, 0, sizeof(tmp_file)); if (invoke_cpp) { char cmd[256], *dir, *base, *a, *b; dir = dirname((a = xstrdup(file))); base = basename((b = xstrdup(file))); slprintf(tmp_file, sizeof(tmp_file), "%s/.tmp-%u-%s", dir, rand(), base); slprintf(cmd, sizeof(cmd), "cpp -I" PREFIX_STRING "/etc/netsniff-ng/ %s > %s", file, tmp_file); system(cmd); file = tmp_file; xfree(a); xfree(b); } if (!strncmp("-", file, strlen("-"))) yyin = stdin; else yyin = fopen(file, "r"); if (!yyin) panic("Cannot open file!\n"); memset(out, 0, sizeof(out)); memset(labels, 0, sizeof(labels)); memset(labels_jf, 0, sizeof(labels_jf)); memset(labels_jt, 0, sizeof(labels_jt)); memset(labels_k, 0, sizeof(labels_k)); stage_1_inline(); stage_2_label_reduce(); res.filter = out; res.len = curr_instr; if (verbose) { printf("Generated program:\n"); bpf_dump_all(&res); } if (!bypass) { if (verbose) { printf("Validating: "); fflush(stdout); } if (__bpf_validate(&res) == 0) { if (verbose) printf("Semantic error! BPF validation failed!\n"); else panic("Semantic error! BPF validation failed! " "Try -V for debugging output!\n"); } else if (verbose) { printf("is runnable!\n"); } } if (verbose) printf("Result:\n"); pretty_printer(&res, format); for (i = 0; i < res.len; ++i) { free(labels[i]); free(labels_jt[i]); free(labels_jf[i]); free(labels_k[i]); } fclose(yyin); if (invoke_cpp) unlink(tmp_file); return 0; } void yyerror(const char *err) { panic("Syntax error at line %d: %s! %s!\n", yylineno, yytext, err); }