Magellan Linux

  • Back to homepage
    • /[magellan-source]/tags/mkinitrd-6_2_0/nash/name_to_dev_t.c

    Contents of /tags/mkinitrd-6_2_0/nash/name_to_dev_t.c

    Parent Directory Parent Directory | Revision Log Revision Log

    Revision 996 - (show annotations) (download)
    Sun May 30 11:54:28 2010 UTC (13 years, 11 months ago) by niro
    File MIME type: text/plain
    File size: 3437 byte(s) 
    tagged 'mkinitrd-6_2_0'
    1 #include <stdlib.h>
    2 #include <string.h>
    3 #include <unistd.h>
    4 #include <ctype.h>
    5 #include <stdio.h>
    6 #include <fcntl.h>
    7 #include <sys/stat.h>
    8
    9 #include "name_to_dev_t.h"
    10
    11 static dev_t
    12 try_name(char *name, int part)
    13 {
    14 char path[64];
    15 char buf[32];
    16 int range;
    17 dev_t res;
    18 char *s;
    19 int len;
    20 int fd;
    21 unsigned int maj, min;
    22 struct stat sb;
    23
    24 /* read device number from .../dev */
    25
    26 sprintf(path, "/sys/block/%s/dev", name);
    27 fd = open(path, O_RDONLY);
    28 if (fd < 0)
    29 goto fail;
    30 len = read(fd, buf, 32);
    31 close(fd);
    32 if (len <= 0 || len == 32 || buf[len - 1] != '\n')
    33 goto fail;
    34 buf[len - 1] = '\0';
    35 if (sscanf(buf, "%u:%u", &maj, &min) != 2)
    36 goto fail;
    37 res = makedev(maj, min);
    38 if (maj != major(res) || min != minor(res))
    39 goto fail;
    40
    41 /* if it's there and we are not looking for a partition - that's it */
    42 if (!part)
    43 return res;
    44
    45 /* otherwise read range from .../range */
    46 snprintf(path, 64, "/sys/block/%s/range", name);
    47 fd = open(path, O_RDONLY);
    48 if (fd < 0)
    49 goto fail;
    50 len = read(fd, buf, 32);
    51 close(fd);
    52 if (len <= 0 || len == 32 || buf[len - 1] != '\n')
    53 goto fail;
    54 buf[len - 1] = '\0';
    55 range = strtoul(buf, &s, 10);
    56 if (*s)
    57 goto fail;
    58
    59 /* if partition is within range - we got it */
    60 if (part < range)
    61 return res + part;
    62 fail:
    63 sprintf(path, "/dev/%s", name);
    64 if (!stat(path, &sb)) {
    65 if (S_ISBLK(sb.st_mode))
    66 return sb.st_rdev;
    67 }
    68 return 0;
    69 }
    70
    71 /*
    72 * Convert a name into device number. We accept the following variants:
    73 *
    74 * 1) device number in hexadecimal represents itself
    75 * 2) /dev/nfs represents Root_NFS (0xff)
    76 * 3) /dev/<disk_name> represents the device number of disk
    77 * 4) /dev/<disk_name><decimal> represents the device number
    78 * of partition - device number of disk plus the partition number
    79 * 5) /dev/<disk_name>p<decimal> - same as the above, that form is
    80 * used when disk name of partitioned disk ends on a digit.
    81 *
    82 * If name doesn't have fall into the categories above, we return 0.
    83 * sysfs is used to check if something is a disk name - it has
    84 * all known disks under bus/block/devices. If the disk name
    85 * contains slashes, name of driverfs node has them replaced with
    86 * bangs. try_name() does the actual checks, assuming that sysfs
    87 * is mounted on /sys.
    88 *
    89 * Note that cases (1) and (2) are already handled by the kernel,
    90 * so we can ifdef them out, provided that we check real-root-dev
    91 * first.
    92 */
    93
    94 dev_t
    95 name_to_dev_t(char *name)
    96 {
    97 char s[32];
    98 char *p;
    99 dev_t res = 0;
    100 int part;
    101
    102 if (strncmp(name, "/dev/", 5) != 0) {
    103 #if 1 /* kernel used to do this */
    104 unsigned maj, min;
    105
    106 if (sscanf(name, "%u:%u", &maj, &min) == 2) {
    107 res = makedev(maj, min);
    108 if (maj != major(res) || min != minor(res))
    109 return 0;
    110 } else {
    111 res = strtoul(name, &p, 16);
    112 if (*p)
    113 return 0;
    114 }
    115 #endif
    116 return res;
    117 }
    118
    119 name += 5;
    120
    121 #if 1 /* kernel used to do this */
    122 if (strcmp(name, "nfs") == 0)
    123 return makedev(0, 255);
    124 #endif
    125 if (strchr(name, '/')) {
    126 res = try_name(name, 1);
    127 if (res)
    128 return res;
    129 }
    130
    131 if (strlen(name) > 31)
    132 return 0;
    133 strcpy(s, name);
    134 for (p = s; *p; p++)
    135 if (*p == '/')
    136 *p = '!';
    137 res = try_name(s, 0);
    138 if (res)
    139 return res;
    140
    141 while (p > s && isdigit(p[-1]))
    142 p--;
    143 if (p == s || !*p || *p == '0')
    144 return 0;
    145 part = strtoul(p, NULL, 10);
    146 *p = '\0';
    147 res = try_name(s, part);
    148 if (res)
    149 return res;
    150
    151 if (p < s + 2 || !isdigit(p[-2]) || p[-1] != 'p')
    152 return 0;
    153 p[-1] = '\0';
    154 return try_name(s, part);
    155 }