awesome/common/util.c

/*
 * util.c - useful functions
 *
 * Copyright © 2007-2008 Julien Danjou <julien@danjou.info>
 * Copyright © 2006 Pierre Habouzit <madcoder@debian.org>
 *
 * 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 2 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, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include "common/util.h"

#include <stdarg.h>
#include <sys/wait.h>
#include <unistd.h>
#include <limits.h>
#include <fcntl.h>
#include <errno.h>
#include <time.h>

const char *
a_current_time_str(void)
{
    static char buffer[25];
    time_t now;
    struct tm tm;

    time(&now);
    localtime_r(&now, &tm);
    if (!strftime(buffer, sizeof(buffer), "%Y-%m-%d %T ", &tm))
        buffer[0] = '\0';

    return buffer;
}

/** Print error and exit with EXIT_FAILURE code.
 */
void
_fatal(int line, const char *fct, const char *fmt, ...)
{
    va_list ap;

    va_start(ap, fmt);
    fprintf(stderr, "%sE: awesome: %s:%d: ", a_current_time_str(), fct, line);
    vfprintf(stderr, fmt, ap);
    va_end(ap);
    fprintf(stderr, "\n");
    exit(EXIT_FAILURE);
}

/** Print error message on stderr.
 */
void
_warn(int line, const char *fct, const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    fprintf(stderr, "%sW: awesome: %s:%d: ", a_current_time_str(), fct, line);
    vfprintf(stderr, fmt, ap);
    va_end(ap);
    fprintf(stderr, "\n");
}

/** \brief safe limited strcpy.
 *
 * Copies at most min(<tt>n-1</tt>, \c l) characters from \c src into \c dst,
 * always adding a final \c \\0 in \c dst.
 *
 * \param[in]  dst      destination buffer.
 * \param[in]  n        size of the buffer. Negative sizes are allowed.
 * \param[in]  src      source string.
 * \param[in]  l        maximum number of chars to copy.
 *
 * \return minimum of  \c src \e length and \c l.
*/
ssize_t
a_strncpy(char *dst, ssize_t n, const char *src, ssize_t l)
{
    ssize_t len = MIN(a_strlen(src), l);

    if (n > 0)
    {
        ssize_t dlen = MIN(n - 1, len);
        memcpy(dst, src, dlen);
        dst[dlen] = '\0';
    }

    return len;
}

/** \brief safe strcpy.
 *
 * Copies at most <tt>n-1</tt> characters from \c src into \c dst, always
 * adding a final \c \\0 in \c dst.
 *
 * \param[in]  dst      destination buffer.
 * \param[in]  n        size of the buffer. Negative sizes are allowed.
 * \param[in]  src      source string.
 * \return \c src \e length. If this value is \>= \c n then the copy was
 *         truncated.
 */
ssize_t
a_strcpy(char *dst, ssize_t n, const char *src)
{
    ssize_t len = a_strlen(src);

    if (n > 0)
    {
        ssize_t dlen = MIN(n - 1, len);
        memcpy(dst, src, dlen);
        dst[dlen] = '\0';
    }

    return len;
}

/** Execute a command and replace the current process.
 * \param cmd The command to execute.
 */
void
a_exec(const char *cmd)
{
    static const char *shell = NULL;

    if(!shell && !(shell = getenv("SHELL")))
        shell = "/bin/sh";

    execlp(shell, shell, "-c", cmd, NULL);
    fatal("execlp() failed: %s", strerror(errno));
}

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