diff options
Diffstat (limited to 'usr.bin/truss/i386-fbsd.c')
| -rw-r--r-- | usr.bin/truss/i386-fbsd.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/usr.bin/truss/i386-fbsd.c b/usr.bin/truss/i386-fbsd.c new file mode 100644 index 0000000..be1d78f --- /dev/null +++ b/usr.bin/truss/i386-fbsd.c @@ -0,0 +1,281 @@ +/* + * FreeBSD/386-specific system call handling. This is probably the most + * complex part of the entire truss program, although I've got lots of + * it handled relatively cleanly now. The system call names are generated + * automatically, thanks to /usr/src/sys/kern/syscalls.master. The + * names used for the various structures are confusing, I sadly admit. + */ +/* + * $Id$ + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <err.h> +#include <signal.h> +#include <fcntl.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include <sys/pioctl.h> +#include <machine/reg.h> +#include <machine/psl.h> +#include <sys/syscall.h> + +#include "syscall.h" + +static int fd = -1; +static int cpid = -1; +extern int Procfd; + +extern FILE *outfile; +#include "syscalls.h" + +static int nsyscalls = sizeof(syscallnames) / sizeof(syscallnames[0]); + +/* + * This is what this particular file uses to keep track of a system call. + * It is probably not quite sufficient -- I can probably use the same + * structure for the various syscall personalities, and I also probably + * need to nest system calls (for signal handlers). + * + * 'struct syscall' describes the system call; it may be NULL, however, + * if we don't know about this particular system call yet. + */ +static struct freebsd_syscall { + struct syscall *sc; + char *name; + int number; + unsigned long *args; + int nargs; /* number of arguments -- *not* number of words! */ + char **s_args; /* the printable arguments */ +} fsc; + +/* Clear up and free parts of the fsc structure. */ +static inline void +clear_fsc() { + if (fsc.args) { + free(fsc.args); + } + if (fsc.s_args) { + int i; + for (i = 0; i < fsc.nargs; i++) + if (fsc.s_args[i]) + free(fsc.s_args[i]); + free(fsc.s_args); + } + memset(&fsc, 0, sizeof(fsc)); +} + +/* + * Called when a process has entered a system call. nargs is the + * number of words, not number of arguments (a necessary distinction + * in some cases). Note that if the STOPEVENT() code in i386/i386/trap.c + * is ever changed these functions need to keep up. + */ + +void +i386_syscall_entry(int pid, int nargs) { + char buf[32]; + struct reg regs = { 0 }; + int syscall; + int i; + int memfd; + unsigned int parm_offset; + struct syscall *sc; + + if (fd == -1 || pid != cpid) { + sprintf(buf, "/proc/%d/regs", pid); + fd = open(buf, O_RDWR); + if (fd == -1) { + fprintf(outfile, "-- CANNOT READ REGISTERS --\n"); + return; + } + cpid = pid; + } + + clear_fsc(); + lseek(fd, 0L, 0); + i = read(fd, ®s, sizeof(regs)); + parm_offset = regs.r_esp + sizeof(int); + + /* + * FreeBSD has two special kinds of system call redirctions -- + * SYS_syscall, and SYS___syscall. The former is the old syscall() + * routine, basicly; the latter is for quad-aligned arguments. + */ + syscall = regs.r_eax; + switch (syscall) { + case SYS_syscall: + lseek(Procfd, parm_offset, SEEK_SET); + read(Procfd, &syscall, sizeof(int)); + parm_offset += sizeof(int); + break; + case SYS___syscall: + lseek(Procfd, parm_offset, SEEK_SET); + read(Procfd, &syscall, sizeof(int)); + parm_offset += sizeof(quad_t); + break; + } + + fsc.number = syscall; + fsc.name = + (syscall < 0 || syscall > nsyscalls) ? NULL : syscallnames[syscall]; + if (!fsc.name) { + fprintf(outfile, "-- UNKNOWN SYSCALL %d --\n", syscall); + } + + if (nargs == 0) + return; + + fsc.args = malloc((1+nargs) * sizeof(unsigned long)); + lseek(Procfd, parm_offset, SEEK_SET); + if (read(Procfd, fsc.args, nargs * sizeof(unsigned long)) == -1) + return; + + sc = get_syscall(fsc.name); + if (sc) { + fsc.nargs = sc->nargs; + } else { +#if DEBUG + fprintf(outfile, "unknown syscall %s -- setting args to %d\n", + fsc.name, nargs); +#endif + fsc.nargs = nargs; + } + + fsc.s_args = malloc((1+fsc.nargs) * sizeof(char*)); + memset(fsc.s_args, 0, fsc.nargs * sizeof(char*)); + fsc.sc = sc; + + /* + * At this point, we set up the system call arguments. + * We ignore any OUT ones, however -- those are arguments that + * are set by the system call, and so are probably meaningless + * now. This doesn't currently support arguments that are + * passed in *and* out, however. + */ + + if (fsc.name) { + char *tmp; + +#if DEBUG + fprintf(stderr, "syscall %s(", fsc.name); +#endif + for (i = 0; i < fsc.nargs; i++) { +#if DEBUG + fprintf(stderr, "0x%x%s", + sc + ? fsc.args[sc->args[i].offset] + : fsc.args[i], + i < (fsc.nargs -1) ? "," : ""); +#endif + if (sc && !(sc->args[i].type & OUT)) { + fsc.s_args[i] = print_arg(Procfd, &sc->args[i], fsc.args); + } + } +#if DEBUG + fprintf(stderr, ")\n"); +#endif + } + +#if DEBUG + fprintf(outfile, "\n"); +#endif + + /* + * Some system calls should be printed out before they are done -- + * execve() and exit(), for example, never return. Possibly change + * this to work for any system call that doesn't have an OUT + * parameter? + */ + + if (!strcmp(fsc.name, "execve") || !strcmp(fsc.name, "exit")) { + print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args); + } + + return; +} + +/* + * And when the system call is done, we handle it here. + * Currently, no attempt is made to ensure that the system calls + * match -- this needs to be fixed (and is, in fact, why S_SCX includes + * the sytem call number instead of, say, an error status). + */ + +void +i386_syscall_exit(int pid, int syscall) { + char buf[32]; + struct reg regs; + int retval; + int i; + int errorp; + struct syscall *sc; + + if (fd == -1 || pid != cpid) { + sprintf(buf, "/proc/%d/regs", pid); + fd = open(buf, O_RDONLY); + if (fd == -1) { + fprintf(outfile, "-- CANNOT READ REGISTERS --\n"); + return; + } + cpid = pid; + } + + lseek(fd, 0L, 0); + if (read(fd, ®s, sizeof(regs)) != sizeof(regs)) + return; + retval = regs.r_eax; + errorp = !!(regs.r_eflags & PSL_C); + + /* + * This code, while simpler than the initial versions I used, could + * stand some significant cleaning. + */ + + sc = fsc.sc; + if (!sc) { + for (i = 0; i < fsc.nargs; i++) { + fsc.s_args[i] = malloc(12); + sprintf(fsc.s_args[i], "0x%x", fsc.args[i]); + } + } else { + /* + * Here, we only look for arguments that have OUT masked in -- + * otherwise, they were handled in the syscall_entry function. + */ + for (i = 0; i < sc->nargs; i++) { + char *temp; + if (sc->args[i].type & OUT) { + /* + * If an error occurred, than don't bothe getting the data; + * it may not be valid. + */ + if (errorp) { + temp = malloc(12); + sprintf(temp, "0x%x", fsc.args[sc->args[i].offset]); + } else { + temp = print_arg(Procfd, &sc->args[i], fsc.args); + } + fsc.s_args[i] = temp; + } + } + } + + /* + * It would probably be a good idea to merge the error handling, + * but that complicates things considerably. + */ + + print_syscall(outfile, fsc.name, fsc.nargs, fsc.s_args); + if (errorp) { + fprintf(outfile, "errno %d '%s'\n", retval, strerror(retval)); + } else { + fprintf(outfile, "returns %d (0x%x)\n", retval, retval); + } + clear_fsc(); + + return; +} |
