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This commit is contained in:
Jim Meyering
1998-03-17 23:31:18 +00:00
parent fcf6405f2d
commit fcbfefa513
1 changed files with 165 additions and 58 deletions
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src/tail.c
+165 -58
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@@ -83,22 +83,51 @@
# define BUFSIZ (512 * 8)
#endif
enum Follow_mode
{
/* FIXME */
follow_name,
/* FIXME */
follow_descriptor,
};
struct File_spec
{
/* The actual file name, or "-" for stdin. */
char *name;
/* The actual file name, or "standard input" for stdin. */
char *pretty_name;
/* File descriptor on which the file is open; -1 if it's not open. */
int fd;
/* The size of the file the last time we checked. */
off_t size;
/* The device and inode of the file the last time we checked. */
dev_t dev;
ino_t ino;
unsigned int no_change_counter;
};
/* If nonzero, interpret the numeric argument as the number of lines.
Otherwise, interpret it as the number of bytes. */
static int count_lines;
/* Whether we follow the name of each file or the file descriptor
that is initially associated with each name. */
/* FIXME: make follow_name the default? */
static enum Follow_mode follow_mode;
/* If nonzero, read from the end of one file until killed. */
static int forever;
/* If nonzero, read from the end of multiple files until killed. */
static int forever_multiple;
/* Array of file descriptors if forever_multiple is 1. */
static int *file_descs;
/* Array of file sizes if forever_multiple is 1. */
static off_t *file_sizes;
/* If nonzero, count from start of file instead of end. */
static int from_start;
@@ -111,6 +140,9 @@ enum header_mode
multiple_files, always, never
};
/* FIXME: rename, document, and use this -- add option */
static unsigned long max_no_change_count = 5;
int safe_read ();
/* The name this program was run with. */
@@ -132,6 +164,8 @@ static struct option const long_options[] =
{
{"bytes", required_argument, NULL, 'c'},
{"follow", no_argument, NULL, 'f'},
{"follow-descriptor", no_argument, NULL, 12},
{"follow-name", no_argument, NULL, 13},
{"lines", required_argument, NULL, 'n'},
{"quiet", no_argument, NULL, 'q'},
{"silent", no_argument, NULL, 'q'},
@@ -566,15 +600,14 @@ output:
return total;
}
/* Tail NFILES (>1) files forever until killed. The file names are in
NAMES. The open file descriptors are in `file_descs', and the size
at which we stopped tailing them is in `file_sizes'. We loop over
each of them, doing an fstat to see if they have changed size. If
none of them have changed size in one iteration, we sleep for a
second and try again. We do this until the user interrupts us. */
/* Tail NFILES (>1) files forever until killed.
The pertinent information for each file is stored in an entry of F.
Loop over each of them, doing an fstat to see if they have changed size.
If none of them have changed size in one iteration, sleep for a
while and try again. Continue until the user interrupts us. */
static void
tail_forever (char **names, int nfiles)
tail_forever (struct File_spec *f, int nfiles)
{
int last;
@@ -590,38 +623,99 @@ tail_forever (char **names, int nfiles)
{
struct stat stats;
if (file_descs[i] < 0)
if (f[i].fd < 0)
continue;
if (fstat (file_descs[i], &stats) < 0)
if (fstat (f[i].fd, &stats) < 0)
{
error (0, errno, "%s", names[i]);
file_descs[i] = -1;
error (0, errno, "%s", f[i].pretty_name);
f[i].fd = -1;
continue;
}
if (stats.st_size == f[i].size)
{
if (++f[i].no_change_counter > max_no_change_count
&& follow_mode == follow_name)
{
/* open/fstat the file and announce if dev/ino
have changed */
struct stat new_stats;
int fd = open (f[i].name, O_RDONLY);
int fail = 0;
if (fd == -1 || fstat (fd, &new_stats) < 0)
{
fail = 1;
error (0, errno, "%s", f[i].pretty_name);
}
else if (!S_ISREG (new_stats.st_mode))
{
fail = 1;
error (0, 0,
_("%s has been replaced with a non-regular file; \
cannot follow end of non-regular file"),
f[i].pretty_name);
}
if (fail)
{
if (f[i].fd != STDIN_FILENO)
close (f[i].fd);
f[i].fd = -1;
}
else if (f[i].ino != new_stats.st_ino
|| f[i].dev != new_stats.st_dev)
{
/* Close the old one. */
if (f[i].fd != STDIN_FILENO)
close (f[i].fd);
/* File has been replaced (e.g., via log rotation) --
tail the new one. */
error (0, 0,
_("%s has been replaced; follow end of new file"),
f[i].pretty_name);
f[i].fd = fd;
f[i].size = new_stats.st_size;
f[i].dev = new_stats.st_dev;
f[i].ino = new_stats.st_ino;
f[i].no_change_counter = 0;
}
/* NEW options: --follow-fd vs. --follow-file */
/* File has been removed -- continue tailing?. */
/* File has been replaced (e.g., log rotation) --
continue tailing old or open the new one?. */
f[i].no_change_counter = 0;
};
continue;
}
if (stats.st_size == file_sizes[i])
continue;
/* This file has changed size. Print out what we can, and
then keep looping. */
changed = 1;
if (stats.st_size < file_sizes[i])
/* reset counter */
f[i].no_change_counter = 0;
if (stats.st_size < f[i].size)
{
write_header (names[i], _("file truncated"));
write_header (f[i].pretty_name, _("file truncated"));
last = i;
lseek (file_descs[i], stats.st_size, SEEK_SET);
file_sizes[i] = stats.st_size;
lseek (f[i].fd, stats.st_size, SEEK_SET);
f[i].size = stats.st_size;
continue;
}
if (i != last)
{
if (print_headers)
write_header (names[i], NULL);
write_header (f[i].pretty_name, NULL);
last = i;
}
file_sizes[i] += dump_remainder (names[i], file_descs[i]);
f[i].size += dump_remainder (f[i].pretty_name, f[i].fd);
}
/* If none of the files changed size, sleep. */
@@ -755,73 +849,75 @@ tail (const char *pretty_filename, int fd, off_t n_units)
return tail_bytes (pretty_filename, fd, n_units);
}
/* Display the last N_UNITS units of file FILENAME.
"-" for FILENAME means the standard input.
FILENUM is this file's index in the list of files the user gave.
/* Display the last N_UNITS units of the file described by F.
Return 0 if successful, 1 if an error occurred. */
static int
tail_file (const char *filename, off_t n_units, int filenum)
tail_file (struct File_spec *f, off_t n_units)
{
int fd, errors;
struct stat stats;
int is_stdin = (STREQ (filename, "-"));
char const *pretty_filename;
int is_stdin = (STREQ (f->name, "-"));
if (is_stdin)
{
have_read_stdin = 1;
pretty_filename = _("standard input");
f->pretty_name = _("standard input");
fd = STDIN_FILENO;
}
else
{
pretty_filename = filename;
fd = open (filename, O_RDONLY);
f->pretty_name = f->name;
fd = open (f->name, O_RDONLY);
}
if (fd == -1)
{
if (forever_multiple)
file_descs[filenum] = -1;
error (0, errno, "%s", pretty_filename);
f->fd = -1;
error (0, errno, "%s", f->pretty_name);
errors = 1;
}
else
{
if (print_headers)
write_header (pretty_filename, NULL);
errors = tail (pretty_filename, fd, n_units);
write_header (f->pretty_name, NULL);
errors = tail (f->pretty_name, fd, n_units);
if (forever_multiple)
{
/* FIXME: duplicate code */
if (fstat (fd, &stats) < 0)
{
error (0, errno, "%s", pretty_filename);
error (0, errno, "%s", f->pretty_name);
errors = 1;
}
else if (!S_ISREG (stats.st_mode))
{
error (0, 0, _("%s: cannot follow end of non-regular file"),
pretty_filename);
f->pretty_name);
errors = 1;
}
if (errors)
{
if (!is_stdin)
close (fd);
file_descs[filenum] = -1;
f->fd = -1;
}
else
{
file_descs[filenum] = fd;
file_sizes[filenum] = stats.st_size;
f->fd = fd;
f->size = stats.st_size;
f->dev = stats.st_dev;
f->ino = stats.st_ino;
f->no_change_counter = 0;
}
}
else
{
if (!is_stdin && close (fd))
{
error (0, errno, "%s", pretty_filename);
error (0, errno, "%s", f->pretty_name);
errors = 1;
}
}
@@ -1032,6 +1128,14 @@ parse_options (int argc, char **argv,
forever = 1;
break;
case 12:
follow_mode = follow_descriptor;
break;
case 13:
follow_mode = follow_name;
break;
case 'q':
*header_mode = never;
break;
@@ -1071,6 +1175,8 @@ main (int argc, char **argv)
off_t n_units = DEFAULT_N_LINES;
int n_files;
char **file;
struct File_spec *F;
int i;
program_name = argv[0];
setlocale (LC_ALL, "");
@@ -1122,27 +1228,28 @@ main (int argc, char **argv)
{
forever_multiple = 1;
forever = 0;
file_descs = (int *) xmalloc (n_files * sizeof (int));
file_sizes = (off_t *) xmalloc (n_files * sizeof (off_t));
}
if (n_files == 0)
{
static char *dummy_stdin = "-";
n_files = 1;
file = &dummy_stdin;
}
F = (struct File_spec *) xmalloc (n_files * sizeof (F[0]));
for (i = 0; i < n_files; i++)
F[i].name = file[i];
if (header_mode == always
|| (header_mode == multiple_files && n_files > 1))
print_headers = 1;
if (n_files == 0)
{
exit_status |= tail_file ("-", n_units, 0);
}
else
{
int i;
for (i = 0; i < n_files; i++)
exit_status |= tail_file (file[i], n_units, i);
for (i = 0; i < n_files; i++)
exit_status |= tail_file (&F[i], n_units);
if (forever_multiple)
tail_forever (file, n_files);
}
if (forever_multiple)
tail_forever (F, n_files);
if (have_read_stdin && close (0) < 0)
error (EXIT_FAILURE, errno, "-");