diff options
Diffstat (limited to 'tail.c')
| -rw-r--r-- | tail.c | 456 |
1 files changed, 203 insertions, 253 deletions
@@ -1,65 +1,30 @@ /* vi: set sw=4 ts=4: */ -/* tail -- output the last part of file(s) - Copyright (C) 89, 90, 91, 95, 1996 Free Software Foundation, Inc. - - 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, 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. - - Original version by Paul Rubin <phr@ocf.berkeley.edu>. - Extensions by David MacKenzie <djm@gnu.ai.mit.edu>. - tail -f for multiple files by Ian Lance Taylor <ian@airs.com>. - - Rewrote the option parser, removed locales support, - and generally busyboxed, Erik Andersen <andersen@lineo.com> - - Removed superfluous options and associated code ("-c", "-n", "-q"). - Removed "tail -f" support for multiple files. - Both changes by Friedrich Vedder <fwv@myrtle.lahn.de>. +/* + * Mini tail implementation for busybox + * + * + * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu> + * + * 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 + * + */ - Compleate Rewrite to correctly support "-NUM", "+NUM", and "-s" by - E.Allen Soard (esp@espsw.net). +#include "busybox.h" - */ #include <sys/types.h> #include <fcntl.h> -#include <stdio.h> -#include <stdlib.h> -#include <unistd.h> -#include <string.h> -#include <getopt.h> -#include "busybox.h" - -#define STDIN "standard input" -#define LINES 0 -#define BYTES 1 - -static int n_files = 0; -static char **files = NULL; -static char * buffer; -static ssize_t bytes_read=0; -static ssize_t bs; -static ssize_t filelocation=0; -static char pip; - -#ifdef BB_FEATURE_SIMPLE_TAIL -static const char unit_type=LINES; -#else -static char unit_type=LINES; -static char verbose = 0; -#endif - -static off_t units=0; static struct suffix_mult tail_suffixes[] = { { "b", 512 }, @@ -68,232 +33,217 @@ static struct suffix_mult tail_suffixes[] = { { NULL, 0 } }; -static int tail_stream(int fd) -{ - ssize_t startpoint; - ssize_t endpoint=0; - ssize_t count=0; - ssize_t filesize=0; - int direction=1; - - filelocation=0; - startpoint=bs=BUFSIZ; - - filesize=lseek(fd, -1, SEEK_END)+1; - pip=(filesize<=0); - - if(units>=0) - lseek(fd,0,SEEK_SET); - else { - direction=-1; - count=1; - } - while(units != 0) { - if (pip) { - char * line; - ssize_t f_size=0; - - bs=BUFSIZ; - line=xmalloc(bs); - while(1) { - bytes_read=read(fd,line,bs); - if(bytes_read<=0) - break; - buffer=xrealloc(buffer,f_size+bytes_read); - memcpy(&buffer[f_size],line,bytes_read); - filelocation=f_size+=bytes_read; - } - bs=f_size; - if(direction<0) - bs--; - if (line) - free(line); - } else { - filelocation = lseek(fd, 0, SEEK_CUR); - if(direction<0) { - if(filelocation<bs) - bs=filelocation; - filelocation = lseek(fd, -bs, SEEK_CUR); - } - bytes_read = read(fd, buffer, bs); - if (bytes_read <= 0) - break; - bs=bytes_read; - } - startpoint=bs; - if(direction>0) { - endpoint=startpoint; - startpoint=0; - } - for(;startpoint!=endpoint;startpoint+=direction) { #ifndef BB_FEATURE_SIMPLE_TAIL - if(unit_type==BYTES) - count++; - else +static struct suffix_mult null_suffixes[] = { + { NULL, 0 } +}; #endif - if(buffer[startpoint-1]=='\n') - count++; - if (!pip) - filelocation=lseek(fd,0,SEEK_CUR); - if(count==units*direction) - break; - } - if((count==units*direction) | pip) - break; - if(direction<0){ - filelocation = lseek(fd, -bytes_read, SEEK_CUR); - if(filelocation==0) - break; - } - } - if(pip && (direction<0)) - bs++; - bytes_read=bs-startpoint; - memcpy(&buffer[0],&buffer[startpoint],bytes_read); - return 0; +#define BYTES 0 +#define LINES 1 + +static char *tailbuf; +static int taillen; +static int newline; + +void tailbuf_append(char *buf, int len) +{ + tailbuf = xrealloc(tailbuf, taillen + len); + memcpy(tailbuf + taillen, buf, len); + taillen += len; } -void add_file(char *name) +void tailbuf_trunc() { - ++n_files; - files = xrealloc(files, n_files); - files[n_files - 1] = (char *) xmalloc(strlen(name) + 1); - strcpy(files[n_files - 1], name); + char *s; + s = memchr(tailbuf, '\n', taillen); + memmove(tailbuf, s + 1, taillen - ((s + 1) - tailbuf)); + taillen -= (s + 1) - tailbuf; + newline = 0; } int tail_main(int argc, char **argv) { - int show_headers = 1; - int test; - int opt; - char follow=0; - int sleep_int=1; - int *fd; - - opterr = 0; - - while ((opt=getopt(argc,argv,"c:fhn:s:q:v")) >0) { + int from_top = 0, units = LINES, count = 10, sleep_period = 1; + int show_headers = 0, hide_headers = 0, follow = 0; + int *fds, nfiles = 0, status = EXIT_SUCCESS, nread, nwrite, seen = 0; + char *s, *start, *end, buf[BUFSIZ]; + int i, opt; + while ((opt = getopt(argc, argv, "c:fhn:q:s:v")) > 0) { switch (opt) { + case 'f': + follow = 1; + break; #ifndef BB_FEATURE_SIMPLE_TAIL - case 'q': - show_headers = 0; - break; - case 's': - sleep_int = atoi(optarg); - if(sleep_int<1) - sleep_int=1; - break; - case 'v': - verbose = 1; - break; - case 'c': - unit_type = BYTES; - /* FALLS THROUGH */ + case 'c': + units = BYTES; + /* FALLS THROUGH */ #endif - case 'n': - test = parse_number(optarg, tail_suffixes); - if (test) { + case 'n': + count = parse_number(optarg, tail_suffixes); + if (count < 0) + count = -count; if (optarg[0] == '+') - units = test; - else - units = -(test+1); - } else + from_top = 1; + break; +#ifndef BB_FEATURE_SIMPLE_TAIL + case 'q': + hide_headers = 1; + break; + case 's': + sleep_period = parse_number(optarg, null_suffixes); + break; + case 'v': + show_headers = 1; + break; +#endif + default: usage(tail_usage); - break; - case 'f': - follow = 1; - break; - default: - usage(tail_usage); } } - while (optind <= argc) { - if(optind==argc) { - if (n_files==0) - add_file(STDIN); - else - break; - }else { - if (!strcmp(argv[optind], "-")) { - add_file(STDIN); - } else { - add_file(argv[optind]); + + /* open all the files */ + fds = (int *)xmalloc(sizeof(int) * (argc - optind + 1)); + if (argc == optind) { + fds[nfiles++] = STDIN_FILENO; + argv[optind] = "standard input"; + } else { + for (i = optind; i < argc; i++) { + if (strcmp(argv[i], "-") == 0) { + fds[nfiles++] = STDIN_FILENO; + argv[i] = "standard input"; + } else if ((fds[nfiles++] = open(argv[i], O_RDONLY)) < 0) { + perror_msg("%s", argv[i]); + status = EXIT_FAILURE; } - optind++; } } - if(units==0) - units=-11; - if(units>0) - units--; - fd=xmalloc(sizeof(int)*n_files); - if (n_files == 1) + #ifndef BB_FEATURE_SIMPLE_TAIL - if (!verbose) + /* tail the files */ + if (!from_top && units == BYTES) + tailbuf = xmalloc(count); #endif - show_headers = 0; - buffer=xmalloc(BUFSIZ); - for (test = 0; test < n_files; test++) { - if (show_headers) - printf("==> %s <==\n", files[test]); - if (!strcmp(files[test], STDIN)) - fd[test] = 0; - else - fd[test] = open(files[test], O_RDONLY); - if (fd[test] == -1) - error_msg_and_die("Unable to open file %s.\n", files[test]); - tail_stream(fd[test]); - bs=BUFSIZ; - while (1) { - if((filelocation>0 || pip)){ - write(1,buffer,bytes_read); + for (i = 0; i < nfiles; i++) { + if (fds[i] == -1) + continue; + seen = 0; + if (show_headers || (!hide_headers && nfiles > 1)) + printf("%s==> %s <==\n", i == 0 ? "" : "\n", argv[optind + i]); + while ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0) { + if (from_top) { +#ifndef BB_FEATURE_SIMPLE_TAIL + if (units == BYTES) { + if (count - 1 <= seen) + nwrite = nread; + else if (count - 1 <= seen + nread) + nwrite = nread + seen - (count - 1); + else + nwrite = 0; + seen += nread; + } else { +#else + { +#endif + if (count - 1 <= seen) + nwrite = nread; + else { + nwrite = 0; + for (s = memchr(buf, '\n', nread); s != NULL; + s = memchr(s+1, '\n', nread - (s + 1 - buf))) { + if (count - 1 <= ++seen) { + nwrite = nread - (s + 1 - buf); + break; + } + } + } + } + if (full_write(STDOUT_FILENO, buf + nread - nwrite, + nwrite) < 0) { + perror_msg("write"); + status = EXIT_FAILURE; + break; + } + } else { +#ifndef BB_FEATURE_SIMPLE_TAIL + if (units == BYTES) { + if (nread < count) { + memmove(tailbuf, tailbuf + nread, count - nread); + memcpy(tailbuf + count - nread, buf, nread); + } else { + memcpy(tailbuf, buf + nread - count, count); + } + seen += nread; + } else { +#else + { +#endif + for (start = buf, end = memchr(buf, '\n', nread); + end != NULL; start = end+1, + end = memchr(start, '\n', nread - (start - buf))) { + if (newline && count <= seen) + tailbuf_trunc(); + tailbuf_append(start, end - start + 1); + seen++; + newline = 1; + } + if (newline && count <= seen && nread - (start - buf) > 0) + tailbuf_trunc(); + tailbuf_append(start, nread - (start - buf)); + } } - bytes_read = read(fd[test], buffer, bs); - filelocation+=bytes_read; - if (bytes_read <= 0) { - break; + } + + if (nread < 0) { + perror_msg("read"); + status = EXIT_FAILURE; + } + +#ifndef BB_FEATURE_SIMPLE_TAIL + if (!from_top && units == BYTES) { + if (count < seen) + seen = count; + if (full_write(STDOUT_FILENO, tailbuf + count - seen, seen) < 0) { + perror_msg("write"); + status = EXIT_FAILURE; } - usleep(sleep_int * 1000); } - if(n_files>1) - printf("\n"); +#endif + + if (!from_top && units == LINES) { + if (full_write(STDOUT_FILENO, tailbuf, taillen) < 0) { + perror_msg("write"); + status = EXIT_FAILURE; + } + } + + taillen = 0; } - while(1){ - for (test = 0; test < n_files; test++) { - if(!follow){ - close(fd[test]); + + while (follow) { + sleep(sleep_period); + + for (i = 0; i < nfiles; i++) { + if (fds[i] == -1) continue; - } else { - sleep(sleep_int); - bytes_read = read(fd[test], buffer, bs); - if(bytes_read>0) { - if (show_headers) - printf("==> %s <==\n", files[test]); - write(1,buffer,bytes_read); - if(n_files>1) - printf("\n"); - } + + if ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0) { + if (show_headers || (!hide_headers && nfiles > 1)) + printf("\n==> %s <==\n", argv[optind + i]); + + do { + full_write(STDOUT_FILENO, buf, nread); + } while ((nread = safe_read(fds[i], buf, sizeof(buf))) > 0); + } + + if (nread < 0) { + perror_msg("read"); + status = EXIT_FAILURE; } } - if(!follow) - break; } - if (fd) - free(fd); - if (buffer) - free(buffer); - if(files) - free(files); - return 0; -} -/* -Local Variables: -c-file-style: "linux" -c-basic-offset: 4 -tab-width: 4 -End: -*/ + return status; +} |