diff options
| author | Ron Yorston | 2015-07-24 14:28:08 +0100 |
|---|---|---|
| committer | Denys Vlasenko | 2015-07-31 16:22:07 +0200 |
| commit | 70b84be9e85969491e542cecc3ae28fa7558a7ec (patch) | |
| tree | 15b5b57b0dd60215e00e0d586ad744452b819026 /miscutils | |
| parent | 159e032bf4cd24535e57daaf29a381b0d5163368 (diff) | |
| download | busybox-70b84be9e85969491e542cecc3ae28fa7558a7ec.zip busybox-70b84be9e85969491e542cecc3ae28fa7558a7ec.tar.gz | |
less: rearrange detection of non-regular files
Move the code to detect non-regular files to the point where the
file is being opened. If num_lines == READING_FILE guarantees
that the file is regular.
Detect when a file becomes unreadable between it first being opened
and the call to update_num_lines. Mark the file as being non-regular
so we don't try that again.
function old new delta
reinitialize 197 245 +48
update_num_lines 159 127 -32
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 48/-32) Total: 16 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'miscutils')
| -rw-r--r-- | miscutils/less.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/miscutils/less.c b/miscutils/less.c index 8fd0874..91a933a 100644 --- a/miscutils/less.c +++ b/miscutils/less.c @@ -167,7 +167,8 @@ enum { pattern_valid = 0 }; enum { READING_FILE = -1, - READING_STDIN = -2 + READING_STDIN = -2, + READING_NONREG = -3 }; struct globals { @@ -615,15 +616,16 @@ static void update_num_lines(void) int count, fd; ssize_t len, i; char buf[4096]; - struct stat stbuf; + /* only do this for regular files */ if (num_lines == READING_FILE) { count = 0; fd = open(filename, O_RDONLY); - if (fd < 0) - goto skip; - if (fstat(fd, &stbuf) != 0 || !S_ISREG(stbuf.st_mode)) - goto do_close; + if (fd < 0) { + /* somebody stole my file! */ + num_lines = READING_NONREG; + return; + } while ((len = safe_read(fd, buf, sizeof(buf))) > 0) { for (i = 0; i < len; ++i) { if (buf[i] == '\n' && ++count == MAXLINES) @@ -632,9 +634,7 @@ static void update_num_lines(void) } done: num_lines = count; - do_close: close(fd); - skip: ; } } @@ -943,6 +943,13 @@ static void buffer_line(int linenum) static void open_file_and_read_lines(void) { if (filename) { +#if ENABLE_FEATURE_LESS_FLAGS + struct stat stbuf; + + xstat(filename, &stbuf); + if (!S_ISREG(stbuf.st_mode)) + num_lines = READING_NONREG; +#endif xmove_fd(xopen(filename, O_RDONLY), STDIN_FILENO); } else { /* "less" with no arguments in argv[] */ |