From ae8dd9f8e65fd7a1df8aa37f154cd1ef26296644 Mon Sep 17 00:00:00 2001 From: Lorenz Stechauner Date: Sat, 1 Mar 2025 14:25:05 +0100 Subject: [PATCH] proj: Implement sigaction --- proj/test1/Makefile | 2 +- proj/test1/src/intercept.c | 158 +++++++++++++++++++++++++++++++------ 2 files changed, 133 insertions(+), 27 deletions(-) diff --git a/proj/test1/Makefile b/proj/test1/Makefile index ca6a02e..35f88a7 100644 --- a/proj/test1/Makefile +++ b/proj/test1/Makefile @@ -25,7 +25,7 @@ main: bin/main.o $(CC) -o $@ $^ $(CFLAGS) -lc -lpthread main_intercept: bin/main.o src/intercept.c - $(CC) -o $@ $^ $(CFLAGS) -lc -Wl,--wrap=malloc,--wrap=free,--wrap=calloc,--wrap=realloc,--wrap=reallocarray,--wrap=getopt,--wrap=exit,--wrap=close,\ + $(CC) -o $@ $^ $(CFLAGS) -lc -Wl,--wrap=malloc,--wrap=free,--wrap=calloc,--wrap=realloc,--wrap=reallocarray,--wrap=getopt,--wrap=exit,--wrap=close,--wrap=sigaction,\ --wrap=sem_init,--wrap=sem_open,--wrap=sem_post,--wrap=sem_wait,--wrap=sem_trywait,--wrap=sem_timedwait,--wrap=sem_getvalue,--wrap=sem_close,--wrap=sem_unlink,--wrap=sem_destroy clean: diff --git a/proj/test1/src/intercept.c b/proj/test1/src/intercept.c index 4b395f5..b44e8be 100644 --- a/proj/test1/src/intercept.c +++ b/proj/test1/src/intercept.c @@ -16,6 +16,7 @@ #include #include #include +#include #define BUFFER_SIZE 256 @@ -28,6 +29,7 @@ static void (*__real_free)(void *); static int (*__real_getopt)(int, char *const [], const char *); static void (*__real_exit)(int); static int (*__real_close)(int); +static int (*__real_sigaction)(int, const struct sigaction *, struct sigaction *); static int (*__real_sem_init)(sem_t *, int, unsigned int); static sem_t *(*__real_sem_open)(const char *, int, ...); static int (*__real_sem_post)(sem_t *); @@ -38,9 +40,9 @@ static int (*__real_sem_getvalue)(sem_t *restrict, int *restrict); static int (*__real_sem_close)(sem_t *); static int (*__real_sem_unlink)(const char *); static int (*__real_sem_destroy)(sem_t *); -#define load(var, name) \ - if (((var) = dlsym(RTLD_NEXT, name)) == NULL) { \ - fprintf(stderr, "intercept: unable to load symbol '%s': %s", name, strerror(errno)); \ +#define load(name) \ + if (((__real_ ## name) = dlsym(RTLD_NEXT, #name)) == NULL) { \ + fprintf(stderr, "intercept: unable to load symbol '%s': %s", #name, strerror(errno)); \ return; \ } #define sym(name) name @@ -53,6 +55,7 @@ extern void __real_free(void *); extern int __real_getopt(int, char *const [], const char *); extern void __real_exit(int); extern int __real_close(int); +extern int __real_sigaction(int, const struct sigaction *, struct sigaction *); extern int __real_sem_init(sem_t *, int, unsigned int); extern sem_t *__real_sem_open(const char *, int, ...); extern int __real_sem_post(sem_t *); @@ -434,24 +437,25 @@ static void fin(void) { static void init(void) { if (mode) return; #ifdef INTERCEPT_PRELOAD - load(__real_malloc, "malloc"); - load(__real_calloc, "calloc"); - load(__real_realloc, "realloc"); - load(__real_reallocarray, "reallocarray"); - load(__real_free, "free"); - load(__real_getopt, "getopt"); - load(__real_exit, "exit"); - load(__real_close, "close"); - load(__real_sem_init, "sem_init"); - load(__real_sem_open, "sem_open"); - load(__real_sem_post, "sem_post"); - load(__real_sem_wait, "sem_wait"); - load(__real_sem_wait, "sem_trywait"); - load(__real_sem_wait, "sem_timedwait"); - load(__real_sem_getvalue, "sem_getvalue"); - load(__real_sem_close, "sem_close"); - load(__real_sem_unlink, "sem_unlink"); - load(__real_sem_destroy, "sem_destroy"); + load(malloc); + load(calloc); + load(realloc); + load(reallocarray); + load(free); + load(getopt); + load(exit); + load(close); + load(sigaction); + load(sem_init); + load(sem_open); + load(sem_post); + load(sem_wait); + load(sem_trywait); + load(sem_timedwait); + load(sem_getvalue); + load(sem_close); + load(sem_unlink); + load(sem_destroy); #endif atexit(fin); const char *val = getenv("INTERCEPT"); @@ -493,7 +497,7 @@ static void init(void) { msg("PID:%li", getpid()); } else if (val && strncmp(val, "tcp://", 6) == 0) { mode = 5; - // TODO + // TODO socket/tcp mode } else { mode = -1; fprintf(stderr, "intercept: not logging or manipulating function/system calls\n"); @@ -624,6 +628,106 @@ int sym(close)(int fildes) { return ret; } +static const char *getsigstr(int sig) { + if (sig == SIGINT) return "SIGINT"; + if (sig == SIGILL) return "SIGILL"; + if (sig == SIGABRT) return "SIGABRT"; + if (sig == SIGFPE) return "SIGFPE"; + if (sig == SIGSEGV) return "SIGSEGV"; + if (sig == SIGTERM) return "SIGTERM"; + if (sig == SIGHUP) return "SIGHUP"; + if (sig == SIGQUIT) return "SIGQUIT"; + if (sig == SIGTRAP) return "SIGTRAP"; + if (sig == SIGKILL) return "SIGKILL"; + if (sig == SIGPIPE) return "SIGPIPE"; + if (sig == SIGALRM) return "SIGALRM"; + if (sig == SIGSTKFLT) return "SIGSTKFLT"; + if (sig == SIGPWR) return "SIGPWR"; + if (sig == SIGBUS) return "SIGBUS"; + if (sig == SIGSYS) return "SIGSYS"; + if (sig == SIGURG) return "SIGURG"; + if (sig == SIGSTOP) return "SIGSTOP"; + if (sig == SIGTSTP) return "SIGTSTP"; + if (sig == SIGCONT) return "SIGCONT"; + if (sig == SIGCHLD) return "SIGCHLD"; + if (sig == SIGTTIN) return "SIGTTIN"; + if (sig == SIGTTOU) return "SIGTTOU"; + if (sig == SIGPOLL) return "SIGPOLL"; + if (sig == SIGXFSZ) return "SIGXFSZ"; + if (sig == SIGXCPU) return "SIGXCPU"; + if (sig == SIGVTALRM) return "SIGVTALRM"; + if (sig == SIGPROF) return "SIGPROF"; + if (sig == SIGUSR1) return "SIGUSR1"; + if (sig == SIGUSR2) return "SIGUSR2"; + if (sig == SIGWINCH) return "SIGWINCH"; + return "?"; +} + +int sym(sigaction)(int sig, const struct sigaction *restrict act, struct sigaction *restrict oact) { + init(); + const char *sigstr = getsigstr(sig); + if (act != NULL) { + char *name = "sa_handler"; + void *ptr = (void *)act->sa_handler; + if (act->sa_flags & SA_SIGINFO) { + name = "sa_sigaction"; + ptr = (void *)act->sa_sigaction; + } + char flgstr[64] = "|"; + if (act->sa_flags & SA_NOCLDSTOP) strcat(flgstr, "SA_NOCLDSTOP|"); + if (act->sa_flags & SA_NOCLDWAIT) strcat(flgstr, "SA_NOCLDWAIT|"); + if (act->sa_flags & SA_SIGINFO) strcat(flgstr, "SA_SIGINFO|"); + if (act->sa_flags & ~(SA_NOCLDSTOP | SA_NOCLDWAIT | SA_SIGINFO)) strcat(flgstr, "?|"); + char maskstr[512] = ""; + for (int i = 0; i < 64; i++) { + if (sigismember(&act->sa_mask, i) != 1) + continue; + if (maskstr[0] != 0) strcat(maskstr, ","); + strcat(maskstr, getsigstr(i)); + } + msg("sigaction(%i:%s, %p:{sa_flags: 0x%x:%s, %s: %p, sa_mask: [%s]}, %p): %p", sig, sigstr, act, act->sa_flags, flgstr, name, ptr, maskstr, oact, __builtin_return_address(0)); + } else { + msg("sigaction(%i:%s, %p:{}, %p): %p", sig, sigstr, act, oact, __builtin_return_address(0)); + } + if (mode >= 4) { + char buf[BUFFER_SIZE]; + rcv(buf, sizeof(buf)); + if (strncmp(buf, "modify ", 7) == 0) { + // TODO sigaction modify + fprintf(stderr, "intercept: sigaction: modify command not implemented\n"); + } else if (strncmp(buf, "return ", 7) == 0) { + // TODO sigaction return + fprintf(stderr, "intercept: sigaction: return command not implemented\n"); + } else if_error_1_int_errno(sigaction, EINVAL) + else if_invalid(sigaction) + } + const int ret = __real_sigaction(sig, act, oact); + if (oact != NULL) { + char *name = "sa_handler"; + void *ptr = (void *)oact->sa_handler; + if (oact->sa_flags & SA_SIGINFO) { + name = "sa_sigaction"; + ptr = (void *)oact->sa_sigaction; + } + char flgstr[64] = "|"; + if (oact->sa_flags & SA_NOCLDSTOP) strcat(flgstr, "SA_NOCLDSTOP|"); + if (oact->sa_flags & SA_NOCLDWAIT) strcat(flgstr, "SA_NOCLDWAIT|"); + if (oact->sa_flags & SA_SIGINFO) strcat(flgstr, "SA_SIGINFO|"); + if (oact->sa_flags & ~(SA_NOCLDSTOP | SA_NOCLDWAIT | SA_SIGINFO)) strcat(flgstr, "?|"); + char maskstr[512] = ""; + for (int i = 0; i < 64; i++) { + if (sigismember(&oact->sa_mask, i) != 1) + continue; + if (maskstr[0] != 0) strcat(maskstr, ","); + strcat(maskstr, getsigstr(i)); + } + msg("return %i; errno %s; oact={sa_flags: 0x%x:%s, %s: %p, sa-mask: [%s]}", ret, strerrorname_np(errno), oact->sa_flags, flgstr, name, ptr, maskstr); + } else { + msg("return %i; errno %s", ret, strerrorname_np(errno)); + } + return ret; +} + int sym(sem_init)(sem_t *sem, int pshared, unsigned int value) { init(); msg("sem_init(%p, %i, %u): %p", sem, pshared, value, __builtin_return_address(0)); @@ -655,7 +759,7 @@ sem_t *sym(sem_open)(const char *name, int oflag, ...) { mode_arg = va_arg(args, mode_t); value = va_arg(args, unsigned int); va_end(args); - msg("sem_open(%es, 0%o:|%s, 0%03o, %u): %p", name, oflag, ostr, mode_arg, value, __builtin_return_address(0)); + msg("sem_open(%es, 0%o:%s, 0%03o, %u): %p", name, oflag, ostr, mode_arg, value, __builtin_return_address(0)); } else { msg("sem_open(%es, 0%o:|%s): %p", name, oflag, ostr, __builtin_return_address(0)); } @@ -710,8 +814,6 @@ sem_t *sym(sem_open)(const char *name, int oflag, ...) { } else { fprintf(stderr, "intercept: sem_open: invalid args in modify command: '%s'\n", buf + 7); \ } - - fprintf(stderr, "intercept: sem_open: not implemented\n"); } else if_return_ptr_errno(sem_open) else if_error_8_ptr_errno(sem_open, EACCES, EEXIST, EINVAL, EMFILE, ENAMETOOLONG, ENFILE, ENOENT, ENOMEM) else if_invalid(sem_open) @@ -832,7 +934,11 @@ int sym(sem_getvalue)(sem_t *restrict sem, int *restrict value) { else if_invalid(sem_getvalue) } const int ret = __real_sem_getvalue(sem, value); - msg("return %i; errno %s; value=%i", ret, strerrorname_np(errno), *value); + if (value != NULL) { + msg("return %i; errno %s; value=%i", ret, strerrorname_np(errno), *value); + } else { + msg("return %i; errno %s", ret, strerrorname_np(errno)); + } return ret; }