diff options
| -rw-r--r-- | coreutils/tail.c | 36 |
1 files changed, 21 insertions, 15 deletions
diff --git a/coreutils/tail.c b/coreutils/tail.c index eac982735..4b42ebc52 100644 --- a/coreutils/tail.c +++ b/coreutils/tail.c @@ -59,7 +59,8 @@ static const struct suffix_mult tail_suffixes[] = { }; struct globals { - bool status; + bool from_top; + bool exitcode; } FIX_ALIASING; #define G (*(struct globals*)&bb_common_bufsiz1) @@ -85,7 +86,7 @@ static ssize_t tail_read(int fd, char *buf, size_t count) r = full_read(fd, buf, count); if (r < 0) { bb_perror_msg(bb_msg_read_error); - G.status = EXIT_FAILURE; + G.exitcode = EXIT_FAILURE; } return r; @@ -99,7 +100,7 @@ static unsigned eat_num(const char *p) p++; else if (*p == '+') { p++; - G.status = 1; /* mark that we saw "+" */ + G.from_top = 1; } return xatou_sfx(p, tail_suffixes); } @@ -109,7 +110,6 @@ int tail_main(int argc, char **argv) { unsigned count = 10; unsigned sleep_period = 1; - bool from_top; const char *str_c, *str_n; char *tailbuf; @@ -152,8 +152,6 @@ int tail_main(int argc, char **argv) #endif argc -= optind; argv += optind; - from_top = G.status; /* 1 if there was "-c +N" or "-n +N" */ - G.status = EXIT_SUCCESS; /* open all the files */ fds = xmalloc(sizeof(fds[0]) * (argc + 1)); @@ -171,7 +169,7 @@ int tail_main(int argc, char **argv) do { int fd = open_or_warn_stdin(argv[i]); if (fd < 0 && !FOLLOW_RETRY) { - G.status = EXIT_FAILURE; + G.exitcode = EXIT_FAILURE; continue; } fds[nfiles] = fd; @@ -183,15 +181,19 @@ int tail_main(int argc, char **argv) /* prepare the buffer */ tailbufsize = BUFSIZ; - if (!from_top && COUNT_BYTES) { + if (!G.from_top && COUNT_BYTES) { if (tailbufsize < count + BUFSIZ) { tailbufsize = count + BUFSIZ; } } - tailbuf = xmalloc(tailbufsize); + /* tail -c1024m REGULAR_FILE doesn't really need 1G mem block. + * (In fact, it doesn't need ANY memory). So delay allocation. + */ + tailbuf = NULL; /* tail the files */ - fmt = header_fmt_str + 1; /* skip header leading newline on first output */ + + fmt = header_fmt_str + 1; /* skip leading newline in the header on the first output */ i = 0; do { char *buf; @@ -209,7 +211,7 @@ int tail_main(int argc, char **argv) fmt = header_fmt_str; } - if (!from_top) { + if (!G.from_top) { off_t current = lseek(fd, 0, SEEK_END); if (current > 0) { unsigned off; @@ -242,6 +244,9 @@ int tail_main(int argc, char **argv) } } + if (!tailbuf) + tailbuf = xmalloc(tailbufsize); + buf = tailbuf; taillen = 0; /* "We saw 1st line/byte". @@ -249,7 +254,7 @@ int tail_main(int argc, char **argv) seen = 1; newlines_seen = 0; while ((nread = tail_read(fd, buf, tailbufsize-taillen)) > 0) { - if (from_top) { + if (G.from_top) { int nwrite = nread; if (seen < count) { /* We need to skip a few more bytes/lines */ @@ -313,7 +318,7 @@ int tail_main(int argc, char **argv) buf = tailbuf + taillen; } } /* while (tail_read() > 0) */ - if (!from_top) { + if (!G.from_top) { xwrite(STDOUT_FILENO, tailbuf, taillen); } } while (++i < nfiles); @@ -368,10 +373,11 @@ int tail_main(int argc, char **argv) xwrite(STDOUT_FILENO, tailbuf, nread); } } while (++i < nfiles); - } + } /* while (1) */ + if (ENABLE_FEATURE_CLEAN_UP) { free(fds); free(tailbuf); } - return G.status; + return G.exitcode; } |