diff options
| -rw-r--r-- | coreutils/Config.in | 2 | ||||
| -rw-r--r-- | coreutils/tail.c | 85 |
2 files changed, 66 insertions, 21 deletions
diff --git a/coreutils/Config.in b/coreutils/Config.in index 1bc047c9a..cacfb9661 100644 --- a/coreutils/Config.in +++ b/coreutils/Config.in @@ -635,7 +635,7 @@ config TAIL from files. config FEATURE_FANCY_TAIL - bool "Enable extra tail options (-q, -s, and -v)" + bool "Enable extra tail options (-q, -s, -v, and -F)" default y depends on TAIL help diff --git a/coreutils/tail.c b/coreutils/tail.c index 3ce6be0bd..ef1326c83 100644 --- a/coreutils/tail.c +++ b/coreutils/tail.c @@ -85,18 +85,15 @@ int tail_main(int argc, char **argv) unsigned count = 10; unsigned sleep_period = 1; bool from_top; - int header_threshhold = 1; const char *str_c, *str_n; char *tailbuf; size_t tailbufsize; - int taillen = 0; - int newlines_seen = 0; - int nfiles, nread, nwrite, i, opt; - unsigned seen; + unsigned header_threshhold = 1; + unsigned nfiles; + int i, opt; int *fds; - char *s, *buf; const char *fmt; #if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_TAIL @@ -110,8 +107,9 @@ int tail_main(int argc, char **argv) } #endif - IF_FEATURE_FANCY_TAIL(opt_complementary = "s+";) /* -s N */ - opt = getopt32(argv, "fc:n:" IF_FEATURE_FANCY_TAIL("qs:v"), + /* -s NUM, -F imlies -f */ + IF_FEATURE_FANCY_TAIL(opt_complementary = "s+:Ff";) + opt = getopt32(argv, "fc:n:" IF_FEATURE_FANCY_TAIL("qs:vF"), &str_c, &str_n IF_FEATURE_FANCY_TAIL(,&sleep_period)); #define FOLLOW (opt & 0x1) #define COUNT_BYTES (opt & 0x2) @@ -119,8 +117,12 @@ int tail_main(int argc, char **argv) if (opt & 0x2) count = eat_num(str_c); // -c if (opt & 0x4) count = eat_num(str_n); // -n #if ENABLE_FEATURE_FANCY_TAIL - if (opt & 0x8) header_threshhold = INT_MAX; // -q + /* q: make it impossible for nfiles to be > header_threshhold */ + if (opt & 0x8) header_threshhold = UINT_MAX; // -q if (opt & 0x20) header_threshhold = 0; // -v +#define FOLLOW_RETRY (opt & 0x40) +#else +#define FOLLOW_RETRY 0 #endif argc -= optind; argv += optind; @@ -128,19 +130,21 @@ int tail_main(int argc, char **argv) G.status = EXIT_SUCCESS; /* open all the files */ - fds = xmalloc(sizeof(int) * (argc + 1)); + fds = xmalloc(sizeof(fds[0]) * (argc + 1)); if (!argv[0]) { struct stat statbuf; - if (!fstat(STDIN_FILENO, &statbuf) && S_ISFIFO(statbuf.st_mode)) { + if (fstat(STDIN_FILENO, &statbuf) == 0 + && S_ISFIFO(statbuf.st_mode) + ) { opt &= ~1; /* clear FOLLOW */ } - *argv = (char *) bb_msg_standard_input; + argv[0] = (char *) bb_msg_standard_input; } nfiles = i = 0; do { int fd = open_or_warn_stdin(argv[i]); - if (fd < 0) { + if (fd < 0 && !FOLLOW_RETRY) { G.status = EXIT_FAILURE; continue; } @@ -161,9 +165,18 @@ int tail_main(int argc, char **argv) tailbuf = xmalloc(tailbufsize); /* tail the files */ - fmt = header_fmt + 1; /* Skip header leading newline on first output. */ + fmt = header_fmt + 1; /* skip header leading newline on first output */ i = 0; do { + char *buf; + int taillen; + int newlines_seen; + unsigned seen; + int nread; + + if (ENABLE_FEATURE_FANCY_TAIL && fds[i] < 0) + continue; /* may happen with -E */ + if (nfiles > header_threshhold) { tail_xprint_header(fmt, argv[i]); fmt = header_fmt; @@ -192,13 +205,13 @@ int tail_main(int argc, char **argv) newlines_seen = 0; while ((nread = tail_read(fds[i], buf, tailbufsize-taillen)) > 0) { if (from_top) { - nwrite = nread; + int nwrite = nread; if (seen < count) { if (COUNT_BYTES) { nwrite -= (count - seen); seen = count; } else { - s = buf; + char *s = buf; do { --nwrite; if (*s++ == '\n' && ++seen == count) { @@ -231,6 +244,7 @@ int tail_main(int argc, char **argv) taillen += nread; } else { int extra = (buf[nread-1] != '\n'); + char *s; k = newlines_seen + newlines_in_buf + extra - count; s = tailbuf; @@ -257,23 +271,54 @@ int tail_main(int argc, char **argv) } } while (++i < nfiles); - buf = xrealloc(tailbuf, BUFSIZ); + tailbuf = xrealloc(tailbuf, BUFSIZ); fmt = NULL; if (FOLLOW) while (1) { sleep(sleep_period); + i = 0; do { + int nread; + const char *filename = argv[i]; + int fd = fds[i]; + + if (FOLLOW_RETRY) { + struct stat sbuf, fsbuf; + + if (fd < 0 + || fstat(fd, &fsbuf) < 0 + || stat(filename, &sbuf) < 0 + || fsbuf.st_dev != sbuf.st_dev + || fsbuf.st_ino != sbuf.st_ino + ) { + int new_fd; + + if (fd >= 0) + close(fd); + new_fd = open(filename, O_RDONLY); + if (new_fd >= 0) { + bb_error_msg("%s has %s; following end of new file", + filename, (fd < 0) ? "appeared" : "been replaced" + ); + } else if (fd >= 0) { + bb_perror_msg("%s has become inaccessible", filename); + } + fds[i] = fd = new_fd; + } + } + if (ENABLE_FEATURE_FANCY_TAIL && fd < 0) + continue; if (nfiles > header_threshhold) { fmt = header_fmt; } - while ((nread = tail_read(fds[i], buf, BUFSIZ)) > 0) { + while ((nread = tail_read(fd, tailbuf, BUFSIZ)) > 0) { if (fmt) { - tail_xprint_header(fmt, argv[i]); + tail_xprint_header(fmt, filename); fmt = NULL; } - xwrite(STDOUT_FILENO, buf, nread); + xwrite(STDOUT_FILENO, tailbuf, nread); } } while (++i < nfiles); } |