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Diffstat (limited to 'src/touch.c')
| -rw-r--r-- | src/touch.c | 438 |
1 files changed, 438 insertions, 0 deletions
diff --git a/src/touch.c b/src/touch.c new file mode 100644 index 0000000..cf6b7b3 --- /dev/null +++ b/src/touch.c @@ -0,0 +1,438 @@ +/* touch -- change modification and access times of files + Copyright (C) 1987-2020 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 3 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, see <https://www.gnu.org/licenses/>. */ + +/* Written by Paul Rubin, Arnold Robbins, Jim Kingdon, David MacKenzie, + and Randy Smith. */ + +#include <config.h> +#include <stdio.h> +#include <getopt.h> +#include <sys/types.h> +#include <assert.h> + +#include "system.h" +#include "argmatch.h" +#include "die.h" +#include "error.h" +#include "fd-reopen.h" +#include "parse-datetime.h" +#include "posixtm.h" +#include "posixver.h" +#include "quote.h" +#include "stat-time.h" +#include "utimens.h" + +/* The official name of this program (e.g., no 'g' prefix). */ +#define PROGRAM_NAME "touch" + +#define AUTHORS \ + proper_name ("Paul Rubin"), \ + proper_name ("Arnold Robbins"), \ + proper_name ("Jim Kingdon"), \ + proper_name ("David MacKenzie"), \ + proper_name ("Randy Smith") + +/* Bitmasks for 'change_times'. */ +#define CH_ATIME 1 +#define CH_MTIME 2 + +/* Which timestamps to change. */ +static int change_times; + +/* (-c) If true, don't create if not already there. */ +static bool no_create; + +/* (-r) If true, use times from a reference file. */ +static bool use_ref; + +/* (-h) If true, change the times of an existing symlink, if possible. */ +static bool no_dereference; + +/* If true, the only thing we have to do is change both the + modification and access time to the current time, so we don't + have to own the file, just be able to read and write it. + On some systems, we can do this if we own the file, even though + we have neither read nor write access to it. */ +static bool amtime_now; + +/* New access and modification times to use when setting time. */ +static struct timespec newtime[2]; + +/* File to use for -r. */ +static char *ref_file; + +/* For long options that have no equivalent short option, use a + non-character as a pseudo short option, starting with CHAR_MAX + 1. */ +enum +{ + TIME_OPTION = CHAR_MAX + 1 +}; + +static struct option const longopts[] = +{ + {"time", required_argument, NULL, TIME_OPTION}, + {"no-create", no_argument, NULL, 'c'}, + {"date", required_argument, NULL, 'd'}, + {"reference", required_argument, NULL, 'r'}, + {"no-dereference", no_argument, NULL, 'h'}, + {GETOPT_HELP_OPTION_DECL}, + {GETOPT_VERSION_OPTION_DECL}, + {NULL, 0, NULL, 0} +}; + +/* Valid arguments to the '--time' option. */ +static char const* const time_args[] = +{ + "atime", "access", "use", "mtime", "modify", NULL +}; + +/* The bits in 'change_times' that those arguments set. */ +static int const time_masks[] = +{ + CH_ATIME, CH_ATIME, CH_ATIME, CH_MTIME, CH_MTIME +}; + +/* Store into *RESULT the result of interpreting FLEX_DATE as a date, + relative to NOW. If NOW is null, use the current time. */ + +static void +get_reldate (struct timespec *result, + char const *flex_date, struct timespec const *now) +{ + if (! parse_datetime (result, flex_date, now)) + die (EXIT_FAILURE, 0, _("invalid date format %s"), quote (flex_date)); +} + +/* Update the time of file FILE according to the options given. + Return true if successful. */ + +static bool +touch (const char *file) +{ + bool ok; + int fd = -1; + int open_errno = 0; + struct timespec const *t = newtime; + + if (STREQ (file, "-")) + fd = STDOUT_FILENO; + else if (! (no_create || no_dereference)) + { + /* Try to open FILE, creating it if necessary. */ + fd = fd_reopen (STDIN_FILENO, file, + O_WRONLY | O_CREAT | O_NONBLOCK | O_NOCTTY, MODE_RW_UGO); + + /* Don't save a copy of errno if it's EISDIR, since that would lead + touch to give a bogus diagnostic for e.g., 'touch /' (assuming + we don't own / or have write access to it). On Solaris 5.6, + and probably other systems, it is EINVAL. On SunOS4, it's EPERM. */ + if (fd == -1 && errno != EISDIR && errno != EINVAL && errno != EPERM) + open_errno = errno; + } + + if (change_times != (CH_ATIME | CH_MTIME)) + { + /* We're setting only one of the time values. */ + if (change_times == CH_MTIME) + newtime[0].tv_nsec = UTIME_OMIT; + else + { + assert (change_times == CH_ATIME); + newtime[1].tv_nsec = UTIME_OMIT; + } + } + + if (amtime_now) + { + /* Pass NULL to futimens so it will not fail if we have + write access to the file, but don't own it. */ + t = NULL; + } + + ok = (fdutimensat (fd, AT_FDCWD, (fd == STDOUT_FILENO ? NULL : file), t, + (no_dereference && fd == -1) ? AT_SYMLINK_NOFOLLOW : 0) + == 0); + + if (fd == STDIN_FILENO) + { + if (close (STDIN_FILENO) != 0) + { + error (0, errno, _("failed to close %s"), quoteaf (file)); + return false; + } + } + else if (fd == STDOUT_FILENO) + { + /* Do not diagnose "touch -c - >&-". */ + if (!ok && errno == EBADF && no_create) + return true; + } + + if (!ok) + { + if (open_errno) + { + /* The wording of this diagnostic should cover at least two cases: + - the file does not exist, but the parent directory is unwritable + - the file exists, but it isn't writable + I think it's not worth trying to distinguish them. */ + error (0, open_errno, _("cannot touch %s"), quoteaf (file)); + } + else + { + if (no_create && errno == ENOENT) + return true; + error (0, errno, _("setting times of %s"), quoteaf (file)); + } + return false; + } + + return true; +} + +void +usage (int status) +{ + if (status != EXIT_SUCCESS) + emit_try_help (); + else + { + printf (_("Usage: %s [OPTION]... FILE...\n"), program_name); + fputs (_("\ +Update the access and modification times of each FILE to the current time.\n\ +\n\ +A FILE argument that does not exist is created empty, unless -c or -h\n\ +is supplied.\n\ +\n\ +A FILE argument string of - is handled specially and causes touch to\n\ +change the times of the file associated with standard output.\n\ +"), stdout); + + emit_mandatory_arg_note (); + + fputs (_("\ + -a change only the access time\n\ + -c, --no-create do not create any files\n\ + -d, --date=STRING parse STRING and use it instead of current time\n\ + -f (ignored)\n\ +"), stdout); + fputs (_("\ + -h, --no-dereference affect each symbolic link instead of any referenced\n\ + file (useful only on systems that can change the\n\ + timestamps of a symlink)\n\ + -m change only the modification time\n\ +"), stdout); + fputs (_("\ + -r, --reference=FILE use this file's times instead of current time\n\ + -t STAMP use [[CC]YY]MMDDhhmm[.ss] instead of current time\n\ + --time=WORD change the specified time:\n\ + WORD is access, atime, or use: equivalent to -a\n\ + WORD is modify or mtime: equivalent to -m\n\ +"), stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + fputs (_("\ +\n\ +Note that the -d and -t options accept different time-date formats.\n\ +"), stdout); + emit_ancillary_info (PROGRAM_NAME); + } + exit (status); +} + +int +main (int argc, char **argv) +{ + int c; + bool date_set = false; + bool ok = true; + char const *flex_date = NULL; + + initialize_main (&argc, &argv); + set_program_name (argv[0]); + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + atexit (close_stdout); + + change_times = 0; + no_create = use_ref = false; + + while ((c = getopt_long (argc, argv, "acd:fhmr:t:", longopts, NULL)) != -1) + { + switch (c) + { + case 'a': + change_times |= CH_ATIME; + break; + + case 'c': + no_create = true; + break; + + case 'd': + flex_date = optarg; + break; + + case 'f': + break; + + case 'h': + no_dereference = true; + break; + + case 'm': + change_times |= CH_MTIME; + break; + + case 'r': + use_ref = true; + ref_file = optarg; + break; + + case 't': + if (! posixtime (&newtime[0].tv_sec, optarg, + PDS_LEADING_YEAR | PDS_CENTURY | PDS_SECONDS)) + die (EXIT_FAILURE, 0, _("invalid date format %s"), + quote (optarg)); + newtime[0].tv_nsec = 0; + newtime[1] = newtime[0]; + date_set = true; + break; + + case TIME_OPTION: /* --time */ + change_times |= XARGMATCH ("--time", optarg, + time_args, time_masks); + break; + + case_GETOPT_HELP_CHAR; + + case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); + + default: + usage (EXIT_FAILURE); + } + } + + if (change_times == 0) + change_times = CH_ATIME | CH_MTIME; + + if (date_set && (use_ref || flex_date)) + { + error (0, 0, _("cannot specify times from more than one source")); + usage (EXIT_FAILURE); + } + + if (use_ref) + { + struct stat ref_stats; + /* Don't use (no_dereference?lstat:stat) (args), since stat + might be an object-like macro. */ + if (no_dereference ? lstat (ref_file, &ref_stats) + : stat (ref_file, &ref_stats)) + die (EXIT_FAILURE, errno, + _("failed to get attributes of %s"), quoteaf (ref_file)); + newtime[0] = get_stat_atime (&ref_stats); + newtime[1] = get_stat_mtime (&ref_stats); + date_set = true; + if (flex_date) + { + if (change_times & CH_ATIME) + get_reldate (&newtime[0], flex_date, &newtime[0]); + if (change_times & CH_MTIME) + get_reldate (&newtime[1], flex_date, &newtime[1]); + } + } + else + { + if (flex_date) + { + struct timespec now; + gettime (&now); + get_reldate (&newtime[0], flex_date, &now); + newtime[1] = newtime[0]; + date_set = true; + + /* If neither -a nor -m is specified, treat "-d now" as if + it were absent; this lets "touch" succeed more often in + the presence of restrictive permissions. */ + if (change_times == (CH_ATIME | CH_MTIME) + && newtime[0].tv_sec == now.tv_sec + && newtime[0].tv_nsec == now.tv_nsec) + { + /* Check that it really was "-d now", and not a timestamp + that just happens to be the current time. */ + struct timespec notnow, notnow1; + notnow.tv_sec = now.tv_sec ^ 1; + notnow.tv_nsec = now.tv_nsec; + get_reldate (¬now1, flex_date, ¬now); + if (notnow1.tv_sec == notnow.tv_sec + && notnow1.tv_nsec == notnow.tv_nsec) + date_set = false; + } + } + } + + /* The obsolete 'MMDDhhmm[YY]' form is valid IFF there are + two or more non-option arguments. */ + if (!date_set && 2 <= argc - optind && posix2_version () < 200112 + && posixtime (&newtime[0].tv_sec, argv[optind], + PDS_TRAILING_YEAR | PDS_PRE_2000)) + { + newtime[0].tv_nsec = 0; + newtime[1] = newtime[0]; + date_set = true; + + if (! getenv ("POSIXLY_CORRECT")) + { + struct tm const *tm = localtime (&newtime[0].tv_sec); + + /* Technically, it appears that even a deliberate attempt to cause + the above localtime to return NULL will always fail because our + posixtime implementation rejects all dates for which localtime + would fail. However, skip the warning if it ever fails. */ + if (tm) + error (0, 0, + _("warning: 'touch %s' is obsolete; use " + "'touch -t %04ld%02d%02d%02d%02d.%02d'"), + argv[optind], + tm->tm_year + 1900L, tm->tm_mon + 1, tm->tm_mday, + tm->tm_hour, tm->tm_min, tm->tm_sec); + } + + optind++; + } + + if (!date_set) + { + if (change_times == (CH_ATIME | CH_MTIME)) + amtime_now = true; + else + newtime[1].tv_nsec = newtime[0].tv_nsec = UTIME_NOW; + } + + if (optind == argc) + { + error (0, 0, _("missing file operand")); + usage (EXIT_FAILURE); + } + + for (; optind < argc; ++optind) + ok &= touch (argv[optind]); + + return ok ? EXIT_SUCCESS : EXIT_FAILURE; +} |