/* ** Copyright (C) 2002 by Kevin L. Mitchell ** ** This program is free software; you can redistribute it and/or modify ** it under the terms of the GNU General Public License as published by ** the Free Software Foundation; either version 2 of the License, or ** (at your option) any later version. ** ** This program is distributed in the hope that it will be useful, ** but WITHOUT ANY WARRANTY; without even the implied warranty of ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ** GNU General Public License for more details. ** ** You should have received a copy of the GNU General Public License ** along with this program; if not, write to the Free Software ** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA ** ** @(#)$Id: ringlog.c 440 2002-12-29 02:55:36Z pierreg0 $ */ /* * This file contains two separate pieces, along with some common * gunk. If RINGLOG_INSTRUMENT is defined, the two special functions * __cyg_profile_func_enter() and __cyg_profile_func_exit() are * defined; otherwise a main function is defined. The common gunk is * init_log(), which opens and, if necessary, initializes a special * binary log file that is treated as a ring buffer (to prevent the * file from growing unboundedly). * * The object produced when compiled with RINGLOG_INSTRUMENT is * designed to work with the special gcc option * -finstrument-functions; this option causes the * __cyg_profile_func_*() functions mentioned above to be called when * a function is entered or exited. (Of course, ringlog.o should * *not* be compiled with this option.) These functions will in turn * call store_entry(), which will call init_log() as needed to open * the log file, ensure that a start record is output, and then will * store records for the function calls. The log file used is * "call.ringlog" in the directory from which the program was * started. * * When RINGLOG_INSTRUMENT is *not* defined while building, a main * function is defined, and the result is an executable for * interpretation of a ringlog. Usage is very simple: All arguments * not beginning with '-' are treated as files to open, and all * arguments beginning with '-' are treated as a specification for the * number of entries new files should be created with. If this * specification is 0 (which it is by default), files will not be * created if they do not already exist. * * For every filename argument, at least one line will be printed * out. If the file is not empty, the entries in the file will be * printed out, one to a line. Each entry is numbered with a logical * number. The entry numbers are followed by a two word description * of the entry type ("Log start," "Function entry," "Function exit," * and "Invalid entry"), followed by a colon (":"), followed by the * word "addr" and the address of the function, followed by the word * "call" and the address from which the function was called. The * ringlog program is not able to convert these addresses to symbols * or file and line numbers--that can be done with a program like * addr2line (part of the binutils package). The output has been * carefully contrived to be parsable by a script. * * The file format is documented below. Note that data is stored in * host byte order. * * 1 2 3 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Magic number | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | First entry | Last entry | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Records | * \ \ * \ \ * | Records | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Record format: * 1 2 3 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Type code | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Function address | * / / * / / * | Function address | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Calling location | * / / * / / * | Calling location | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Some systems may have pointers larger than 32 bits, which is why these * fields are allowed to be variable width. */ #include #include #include #include #include #include #include #include #include #include /* /etc/magic rules: * * 0 belong 0x52e45fd4 RingLog call trace file, big endian * >4 beshort x (First entry %u, * >>6 beshort x last entry %u) * 0 lelong 0x52e45fd4 RingLog call trace file, little endian * >4 leshort x (First entry %u, * >>6 leshort x last entry %u) */ #define RINGLOG_MAGIC 0x52e45fd4 /* verify file format */ #define RINGLOG_INIT 0x00000000 /* mark when a session was initiated */ #define RINGLOG_ENTER 0x01010101 /* record function entry */ #define RINGLOG_EXIT 0x02020202 /* record function exit */ #define RINGLOG_FNAME "call.ringlog" /* default file name */ #define RINGLOG_ILEN 2000 /* default number of entries */ /* length of the header and of individual entries */ #define HEAD_LEN (sizeof(u_int32_t) + 2 * sizeof(u_int16_t)) #define ENTRY_LEN (sizeof(u_int32_t) + 2 * sizeof(void *)) /* return an lvalue to the specified type stored at the specified location */ #define rl_ref(log, loc, type) (*((type *)((log) + (loc)))) /* access particular header fields */ #define rl_magic(log) rl_ref((log), 0, u_int32_t) #define rl_first(log) rl_ref((log), 4, u_int16_t) #define rl_last(log) rl_ref((log), 6, u_int16_t) /* translate physical entry number to a file location */ #define rl_addr(loc) ((loc) * ENTRY_LEN + HEAD_LEN) /* extract the type, function, and call fields of an entry */ #define rl_type(log, loc) rl_ref((log), rl_addr(loc), u_int32_t) #define rl_func(log, loc) rl_ref((log), rl_addr(loc) + sizeof(u_int32_t), \ void *) #define rl_call(log, loc) rl_ref((log), rl_addr(loc) + sizeof(u_int32_t) + \ sizeof(void *), void *) static char *log = 0; /* the log has to be global data */ static size_t log_size = 0; /* remember the size of the log */ static int log_length = 0; /* remember how many entries it'll hold */ /* Open and initialize the log file */ static int init_log(char *fname, size_t init_len) { char c = 0; int fd, err = 0, size = -1; struct stat buf; /* open file */ if ((fd = open(fname, O_RDWR | (init_len > 0 ? O_CREAT : 0), S_IRUSR | S_IWUSR)) < 0) return errno; /* return error */ if (fstat(fd, &buf)) { /* get size */ err = errno; /* save errno... */ close(fd); /* close file descriptor */ return err; /* return error */ } if (buf.st_size <= 8) /* too small */ size = HEAD_LEN + ENTRY_LEN * init_len; else if ((buf.st_size - 8) % ENTRY_LEN) /* not a multiple of entry length */ size = ((buf.st_size - 8) / ENTRY_LEN + 1) * ENTRY_LEN + 8; /* round up */ if (size >= 0) { /* need to set the size */ if (lseek(fd, size - 1, SEEK_SET) < 0) { /* seek to the end of our file */ err = errno; /* save errno... */ close(fd); /* close file descriptor */ return err; /* return error */ } if (write(fd, &c, 1) < 0) { /* write a zero to set the new size */ err = errno; /* save errno... */ close(fd); /* close file descriptor */ return err; /* return error */ } log_size = size; /* record log size */ } else log_size = buf.st_size; /* record log size */ /* map the file to memory */ if ((log = (char *)mmap(0, log_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) err = errno; /* save errno... */ close(fd); /* don't need the file descriptor anymore */ if (err) /* an error occurred while mapping the file; return it */ return err; log_length = (log_size - HEAD_LEN) / ENTRY_LEN; /* store number of entries */ if (rl_magic(log) == 0) { /* initialize if necessary */ rl_magic(log) = RINGLOG_MAGIC; rl_first(log) = -1; rl_last(log) = -1; } if (rl_magic(log) != RINGLOG_MAGIC) { /* verify file format */ munmap(log, log_size); /* unmap file */ return -1; /* -1 indicates file format error */ } return 0; /* return success */ } #ifdef RINGLOG_INSTRUMENT /* store an entry in the log file */ static void store_entry(u_int32_t type, void *this_fn, void *call_site) { if (!log) { /* open the log file if necessary; die if unable */ assert(init_log(RINGLOG_FNAME, RINGLOG_ILEN) == 0); store_entry(RINGLOG_INIT, 0, 0); /* mark start of logging */ } if (++(rl_last(log)) >= log_length) /* select next entry to fill */ rl_last(log) = 0; /* wrap if needed */ if (rl_first(log) == rl_last(log)) { /* advance start pointer if collision */ if (++(rl_first(log)) >= log_length) /* wrap if necessary */ rl_first(log) = 0; } else if (rl_first(log) == (u_int16_t)-1) /* no entries yet; enter one */ rl_first(log) = 0; rl_type(log, rl_last(log)) = type; /* record the entry */ rl_func(log, rl_last(log)) = this_fn; rl_call(log, rl_last(log)) = call_site; } /* called upon function entry */ void __cyg_profile_func_enter(void *this_fn, void *call_site) { store_entry(RINGLOG_ENTER, this_fn, call_site); } /* called upon function exit */ void __cyg_profile_func_exit(void *this_fn, void *call_site) { store_entry(RINGLOG_EXIT, this_fn, call_site); } #else /* !defined(RINGLOG_INSTRUMENT) */ /* converts a type to a printable string */ static char * get_type(u_int32_t type) { switch (type) { case RINGLOG_INIT: return " Logging start"; break; case RINGLOG_ENTER: return "Function entry"; break; case RINGLOG_EXIT: return " Function exit"; break; } return " Invalid entry"; } /* Print out entries from a starting point to an end point */ static void extract(int *count, u_int16_t start, u_int16_t end) { for (; start <= end; start++) printf("% 4d %s: addr %p call %p\n", (*count)++, get_type(rl_type(log, start)), rl_func(log, start), rl_call(log, start)); } int main(int argc, char **argv) { char *arg; int i, err, size = 0; while ((arg = *++argv)) { if (arg[0] == '-') { /* - turns into log file size */ size = atoi(arg + 1); continue; } log = 0; /* initialize our data */ log_size = 0; log_length = 0; switch ((err = init_log(arg, size))) { /* initialize the log */ case -1: /* file is in an invalid format */ printf("File %s not a valid ringlog file\n", arg); continue; break; case 0: /* file has opened and is ready to be read */ break; default: /* some error occurred */ printf("Error %d opening file %s: %s\n", err, arg, strerror(err)); continue; break; } if (rl_first(log) == (u_int16_t)-1) /* it's an empty file */ printf("File %s is empty\n", arg); else { /* print out file contents */ printf("File %s contents:\n", arg); i = 0; /* initialize counter */ if (rl_last(log) <= rl_first(log)) { /* print out log file */ extract(&i, rl_first(log), log_length - 1); /* end of buffer... */ extract(&i, 0, rl_last(log)); /* then beginning of buffer */ } else extract(&i, rl_first(log), rl_last(log)); } munmap(log, log_size); /* unmap the file */ } return 0; } #endif /* !RINGLOG_INSTRUMENT */