lib/path.c

   1 /*
   2  * Simple functions to access files.
   3  *
   4  * Taken from lscpu.c
   5  *
   6  * Copyright (C) 2008 Cai Qian <qcai@redhat.com>
   7  * Copyright (C) 2008 Karel Zak <kzak@redhat.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it would be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  22  */
  23
  24 #include <stdarg.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27 #include <stdio.h>
  28 #include <errno.h>
  29
  30 #include "all-io.h"
  31 #include "cpuset.h"
  32 #include "path.h"
  33 #include "nls.h"
  34 #include "c.h"
  35
  36 static size_t prefixlen;
  37 static char pathbuf[PATH_MAX];
  38
  39 static const char *
  40 path_vcreate(const char *path, va_list ap)
  41 {
  42         if (prefixlen)
  43                 vsnprintf(pathbuf + prefixlen,
  44                           sizeof(pathbuf) - prefixlen, path, ap);
  45         else
  46                 vsnprintf(pathbuf, sizeof(pathbuf), path, ap);
  47         return pathbuf;
  48 }
  49
  50 static FILE *
  51 path_vfopen(const char *mode, int exit_on_error, const char *path, va_list ap)
  52 {
  53         FILE *f;
  54         const char *p = path_vcreate(path, ap);
  55
  56         f = fopen(p, mode);
  57         if (!f && exit_on_error)
  58                 err(EXIT_FAILURE, _("cannot open %s"), p);
  59         return f;
  60 }
  61
  62 static int
  63 path_vopen(int flags, const char *path, va_list ap)
  64 {
  65         int fd;
  66         const char *p = path_vcreate(path, ap);
  67
  68         fd = open(p, flags);
  69         if (fd == -1)
  70                 err(EXIT_FAILURE, _("cannot open %s"), p);
  71         return fd;
  72 }
  73
  74 FILE *
  75 path_fopen(const char *mode, int exit_on_error, const char *path, ...)
  76 {
  77         FILE *fd;
  78         va_list ap;
  79
  80         va_start(ap, path);
  81         fd = path_vfopen(mode, exit_on_error, path, ap);
  82         va_end(ap);
  83
  84         return fd;
  85 }
  86
  87 void
  88 path_getstr(char *result, size_t len, const char *path, ...)
  89 {
  90         FILE *fd;
  91         va_list ap;
  92
  93         va_start(ap, path);
  94         fd = path_vfopen("r", 1, path, ap);
  95         va_end(ap);
  96
  97         if (!fgets(result, len, fd))
  98                 err(EXIT_FAILURE, _("failed to read: %s"), pathbuf);
  99         fclose(fd);
 100
 101         len = strlen(result);
 102         if (result[len - 1] == '\n')
 103                 result[len - 1] = '\0';
 104 }
 105
 106 int
 107 path_getnum(const char *path, ...)
 108 {
 109         FILE *fd;
 110         va_list ap;
 111         int result;
 112
 113         va_start(ap, path);
 114         fd = path_vfopen("r", 1, path, ap);
 115         va_end(ap);
 116
 117         if (fscanf(fd, "%d", &result) != 1) {
 118                 if (ferror(fd))
 119                         err(EXIT_FAILURE, _("failed to read: %s"), pathbuf);
 120                 else
 121                         errx(EXIT_FAILURE, _("parse error: %s"), pathbuf);
 122         }
 123         fclose(fd);
 124         return result;
 125 }
 126
 127 int
 128 path_writestr(const char *str, const char *path, ...)
 129 {
 130         int fd, result;
 131         va_list ap;
 132
 133         va_start(ap, path);
 134         fd = path_vopen(O_WRONLY, path, ap);
 135         va_end(ap);
 136         result = write_all(fd, str, strlen(str));
 137         close(fd);
 138         return result;
 139 }
 140
 141 int
 142 path_exist(const char *path, ...)
 143 {
 144         va_list ap;
 145         const char *p;
 146
 147         va_start(ap, path);
 148         p = path_vcreate(path, ap);
 149         va_end(ap);
 150
 151         return access(p, F_OK) == 0;
 152 }
 153
 154 static cpu_set_t *
 155 path_cpuparse(int maxcpus, int islist, const char *path, va_list ap)
 156 {
 157         FILE *fd;
 158         cpu_set_t *set;
 159         size_t setsize, len = maxcpus * 7;
 160         char buf[len];
 161
 162         fd = path_vfopen("r", 1, path, ap);
 163
 164         if (!fgets(buf, len, fd))
 165                 err(EXIT_FAILURE, _("failed to read: %s"), pathbuf);
 166         fclose(fd);
 167
 168         len = strlen(buf);
 169         if (buf[len - 1] == '\n')
 170                 buf[len - 1] = '\0';
 171
 172         set = cpuset_alloc(maxcpus, &setsize, NULL);
 173         if (!set)
 174                 err(EXIT_FAILURE, _("failed to callocate cpu set"));
 175
 176         if (islist) {
 177                 if (cpulist_parse(buf, set, setsize, 0))
 178                         errx(EXIT_FAILURE, _("failed to parse CPU list %s"), buf);
 179         } else {
 180                 if (cpumask_parse(buf, set, setsize))
 181                         errx(EXIT_FAILURE, _("failed to parse CPU mask %s"), buf);
 182         }
 183         return set;
 184 }
 185
 186 cpu_set_t *
 187 path_cpuset(int maxcpus, const char *path, ...)
 188 {
 189         va_list ap;
 190         cpu_set_t *set;
 191
 192         va_start(ap, path);
 193         set = path_cpuparse(maxcpus, 0, path, ap);
 194         va_end(ap);
 195
 196         return set;
 197 }
 198
 199 cpu_set_t *
 200 path_cpulist(int maxcpus, const char *path, ...)
 201 {
 202         va_list ap;
 203         cpu_set_t *set;
 204
 205         va_start(ap, path);
 206         set = path_cpuparse(maxcpus, 1, path, ap);
 207         va_end(ap);
 208
 209         return set;
 210 }
 211
 212 void
 213 path_setprefix(const char *prefix)
 214 {
 215         prefixlen = strlen(prefix);
 216         strncpy(pathbuf, prefix, sizeof(pathbuf));
 217         pathbuf[sizeof(pathbuf) - 1] = '\0';
 218 }