common/util.c

   1 /*
   2  * util.c - useful functions
   3  *
   4  * Copyright © 2007-2008 Julien Danjou <julien@danjou.info>
   5  * Copyright © 2006 Pierre Habouzit <madcoder@debian.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  */
  22
  23 #include <stdarg.h>
  24 #include <sys/wait.h>
  25 #include <unistd.h>
  26 #include <limits.h>
  27 #include <fcntl.h>
  28 #include <errno.h>
  29
  30 #include "common/util.h"
  31
  32 /** Print error and exit with EXIT_FAILURE code.
  33  */
  34 void
  35 _fatal(int line, const char *fct, const char *fmt, ...)
  36 {
  37     va_list ap;
  38
  39     va_start(ap, fmt);
  40     fprintf(stderr, "E: awesome: %s:%d: ", fct, line);
  41     vfprintf(stderr, fmt, ap);
  42     va_end(ap);
  43     fprintf(stderr, "\n");
  44     exit(EXIT_FAILURE);
  45 }
  46
  47 /** Print error message on stderr.
  48  */
  49 void
  50 _warn(int line, const char *fct, const char *fmt, ...)
  51 {
  52     va_list ap;
  53     va_start(ap, fmt);
  54     fprintf(stderr, "W: awesome: %s:%d: ", fct, line);
  55     vfprintf(stderr, fmt, ap);
  56     va_end(ap);
  57     fprintf(stderr, "\n");
  58 }
  59
  60 /** \brief safe limited strcpy.
  61  *
  62  * Copies at most min(<tt>n-1</tt>, \c l) characters from \c src into \c dst,
  63  * always adding a final \c \\0 in \c dst.
  64  *
  65  * \param[in]  dst      destination buffer.
  66  * \param[in]  n        size of the buffer. Negative sizes are allowed.
  67  * \param[in]  src      source string.
  68  * \param[in]  l        maximum number of chars to copy.
  69  *
  70  * \return minimum of  \c src \e length and \c l.
  71 */
  72 ssize_t
  73 a_strncpy(char *dst, ssize_t n, const char *src, ssize_t l)
  74 {
  75     ssize_t len = MIN(a_strlen(src), l);
  76
  77     if (n > 0)
  78     {
  79         ssize_t dlen = MIN(n - 1, len);
  80         memcpy(dst, src, dlen);
  81         dst[dlen] = '\0';
  82     }
  83
  84     return len;
  85 }
  86
  87 /** \brief safe strcpy.
  88  *
  89  * Copies at most <tt>n-1</tt> characters from \c src into \c dst, always
  90  * adding a final \c \\0 in \c dst.
  91  *
  92  * \param[in]  dst      destination buffer.
  93  * \param[in]  n        size of the buffer. Negative sizes are allowed.
  94  * \param[in]  src      source string.
  95  * \return \c src \e length. If this value is \>= \c n then the copy was
  96  *         truncated.
  97  */
  98 ssize_t
  99 a_strcpy(char *dst, ssize_t n, const char *src)
 100 {
 101     ssize_t len = a_strlen(src);
 102
 103     if (n > 0)
 104     {
 105         ssize_t dlen = MIN(n - 1, len);
 106         memcpy(dst, src, dlen);
 107         dst[dlen] = '\0';
 108     }
 109
 110     return len;
 111 }
 112
 113 /** Execute a command and replace the current process.
 114  * \param cmd The command to execute.
 115  */
 116 void
 117 a_exec(const char *cmd)
 118 {
 119     static const char *shell = NULL;
 120
 121     if(!shell && !(shell = getenv("SHELL")))
 122         shell = "/bin/sh";
 123
 124     execl(shell, shell, "-c", cmd, NULL);
 125     fatal("execv() failed: %s", strerror(errno));
 126 }
 127
 128 // vim: filetype=c:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80