问题
I want to list files and directories under "/proc" in Android. When running as my application process, many files are not readable.
If I list the directory as the shell user I get the following output:
shell@flounder:/ $ whoami
shell
shell@flounder:/ $ /system/bin/toolbox ls -l /proc
dr-xr-xr-x root root 2015-09-12 03:30 1
dr-xr-xr-x root root 2015-09-12 03:31 10
dr-xr-xr-x root root 2015-09-12 03:31 101
dr-xr-xr-x shell shell 2015-09-15 03:24 10196
dr-xr-xr-x root root 2015-09-12 03:31 102
dr-xr-xr-x root root 2015-09-12 03:31 103
dr-xr-xr-x root root 2015-09-12 03:31 104
dr-xr-xr-x u0_a15 u0_a15 2015-09-14 07:37 10451
dr-xr-xr-x root root 2015-09-12 03:31 105
dr-xr-xr-x wifi wifi 2015-09-14 08:53 10570
dr-xr-xr-x root root 2015-09-12 03:31 106
dr-xr-xr-x root root 2015-09-12 03:31 107
dr-xr-xr-x root root 2015-09-12 03:31 108
dr-xr-xr-x root root 2015-09-12 03:31 11
dr-xr-xr-x root root 2015-09-12 03:31 110
dr-xr-xr-x root root 2015-09-12 03:31 111
dr-xr-xr-x root root 2015-09-12 03:31 112
dr-xr-xr-x root root 2015-09-12 03:31 113
dr-xr-xr-x root root 2015-09-12 03:31 114
dr-xr-xr-x root root 2015-09-12 03:31 115
dr-xr-xr-x root root 2015-09-12 03:31 116
dr-xr-xr-x root root 2015-09-12 03:31 117
dr-xr-xr-x root root 2015-09-12 03:31 118
dr-xr-xr-x root root 2015-09-12 03:31 119
dr-xr-xr-x u0_a26 u0_a26 2015-09-12 03:31 1193
dr-xr-xr-x root root 2015-09-12 03:31 12
dr-xr-xr-x root root 2015-09-12 03:31 120
dr-xr-xr-x u0_a57 u0_a57 2015-09-12 03:31 1209
dr-xr-xr-x root root 2015-09-12 03:31 121
dr-xr-xr-x root root 2015-09-12 03:31 122
dr-xr-xr-x nfc nfc 2015-09-12 03:31 1227
dr-xr-xr-x root root 2015-09-12 03:31 123
dr-xr-xr-x radio radio 2015-09-12 03:31 1239
dr-xr-xr-x root root 2015-09-12 03:31 124
dr-xr-xr-x u0_a26 u0_a26 2015-09-12 03:31 1246
dr-xr-xr-x root root 2015-09-12 03:31 125
dr-xr-xr-x root root 2015-09-12 03:31 126
dr-xr-xr-x root root 2015-09-12 03:31 127
dr-xr-xr-x root root 2015-09-12 03:30 128
dr-xr-xr-x root root 2015-09-12 03:31 13
dr-xr-xr-x u0_a26 u0_a26 2015-09-12 03:31 1305
dr-xr-xr-x root root 2015-09-12 03:30 132
dr-xr-xr-x root root 2015-09-12 03:31 134
dr-xr-xr-x u0_a86 u0_a86 2015-09-14 07:16 1343
dr-xr-xr-x root root 2015-09-12 03:31 135
dr-xr-xr-x root root 2015-09-12 03:31 136
dr-xr-xr-x root root 2015-09-12 03:31 137
dr-xr-xr-x root root 2015-09-12 03:31 138
dr-xr-xr-x root root 2015-09-12 03:31 139
dr-xr-xr-x root root 2015-09-12 03:31 14
dr-xr-xr-x root root 2015-09-12 03:31 140
dr-xr-xr-x root root 2015-09-12 03:31 141
dr-xr-xr-x root root 2015-09-12 03:31 142
dr-xr-xr-x root root 2015-09-12 03:31 143
dr-xr-xr-x root root 2015-09-12 03:31 144
dr-xr-xr-x root root 2015-09-12 03:31 145
dr-xr-xr-x root root 2015-09-12 03:31 149
dr-xr-xr-x root root 2015-09-12 03:31 150
dr-xr-xr-x logd logd 2015-09-12 03:30 153
dr-xr-xr-x root root 2015-09-12 03:30 155
dr-xr-xr-x root root 2015-09-12 03:31 16
dr-xr-xr-x root root 2015-09-12 03:31 160
dr-xr-xr-x root root 2015-09-12 03:30 163
dr-xr-xr-x root root 2015-09-12 03:30 164
dr-xr-xr-x system system 2015-09-12 03:30 165
dr-xr-xr-x u0_a9 u0_a9 2015-09-12 03:31 1652
dr-xr-xr-x system graphics 2015-09-12 03:30 166
dr-xr-xr-x root root 2015-09-12 03:31 17
dr-xr-xr-x system system 2015-09-14 05:30 18227
dr-xr-xr-x root root 2015-09-12 03:31 188
dr-xr-xr-x root root 2015-09-12 03:31 192
dr-xr-xr-x root root 2015-09-12 03:31 193
dr-xr-xr-x root root 2015-09-12 03:31 194
dr-xr-xr-x root root 2015-09-12 03:31 195
dr-xr-xr-x root root 2015-09-12 03:31 2
dr-xr-xr-x root root 2015-09-12 03:31 20
dr-xr-xr-x u0_a19 u0_a19 2015-09-14 05:36 20564
dr-xr-xr-x root root 2015-09-12 03:31 207
dr-xr-xr-x u0_a45 u0_a45 2015-09-15 03:00 20763
dr-xr-xr-x root root 2015-09-12 03:31 208
dr-xr-xr-x root root 2015-09-12 03:31 21
dr-xr-xr-x shell shell 2015-09-12 03:31 210
dr-xr-xr-x root root 2015-09-12 03:31 215
dr-xr-xr-x root root 2015-09-12 03:31 216
dr-xr-xr-x root root 2015-09-12 03:31 217
dr-xr-xr-x drm drm 2015-09-12 03:31 218
dr-xr-xr-x media audio 2015-09-12 03:31 219
dr-xr-xr-x root root 2015-09-12 03:31 22
dr-xr-xr-x root root 2015-09-12 03:31 220
dr-xr-xr-x keystore keystore 2015-09-12 03:31 222
dr-xr-xr-x system system 2015-09-12 03:31 223
dr-xr-xr-x root root 2015-09-12 03:31 224
dr-xr-xr-x root root 2015-09-12 03:31 225
dr-xr-xr-x shell shell 2015-09-15 03:15 2258
dr-xr-xr-x system root 2015-09-12 03:31 226
dr-xr-xr-x gps system 2015-09-12 03:31 227
dr-xr-xr-x u0_a67 u0_a67 2015-09-15 03:15 2270
dr-xr-xr-x root root 2015-09-12 03:31 23
dr-xr-xr-x root root 2015-09-12 03:31 24
dr-xr-xr-x root root 2015-09-12 03:31 2428
dr-xr-xr-x root root 2015-09-15 03:05 24353
dr-xr-xr-x root root 2015-09-12 03:31 25
dr-xr-xr-x root root 2015-09-15 03:11 25597
dr-xr-xr-x root root 2015-09-12 03:31 26
dr-xr-xr-x root root 2015-09-15 03:11 26671
dr-xr-xr-x root root 2015-09-12 03:31 27
dr-xr-xr-x u0_a84 u0_a84 2015-09-15 03:15 2738
dr-xr-xr-x root root 2015-09-12 03:31 28
dr-xr-xr-x root root 2015-09-12 03:31 29
dr-xr-xr-x root root 2015-09-15 03:11 29355
dr-xr-xr-x root root 2015-09-15 03:16 2958
dr-xr-xr-x root root 2015-09-12 03:31 3
dr-xr-xr-x root root 2015-09-12 03:31 30
dr-xr-xr-x u0_a5 u0_a5 2015-09-15 03:10 30095
dr-xr-xr-x u0_a18 u0_a18 2015-09-15 03:11 30266
dr-xr-xr-x u0_a40 u0_a40 2015-09-15 03:11 30290
dr-xr-xr-x system system 2015-09-15 03:11 30333
dr-xr-xr-x u0_a37 u0_a37 2015-09-15 03:11 30382
dr-xr-xr-x u0_a77 u0_a77 2015-09-15 03:11 30420
dr-xr-xr-x u0_a61 u0_a61 2015-09-15 03:11 30458
dr-xr-xr-x root root 2015-09-14 09:56 30729
dr-xr-xr-x u0_a4 u0_a4 2015-09-14 11:12 30994
dr-xr-xr-x root root 2015-09-12 03:31 31
dr-xr-xr-x u0_a9 u0_a9 2015-09-14 13:31 31453
dr-xr-xr-x shell shell 2015-09-15 03:12 31844
dr-xr-xr-x root root 2015-09-12 03:31 32
dr-xr-xr-x u0_a6 u0_a6 2015-09-15 01:13 32176
dr-xr-xr-x root root 2015-09-15 02:34 32422
dr-xr-xr-x root root 2015-09-15 03:13 32476
dr-xr-xr-x shell shell 2015-09-15 02:39 32552
dr-xr-xr-x root root 2015-09-12 03:31 33
dr-xr-xr-x root root 2015-09-12 03:31 47
dr-xr-xr-x root root 2015-09-12 03:31 48
dr-xr-xr-x root root 2015-09-12 03:31 49
dr-xr-xr-x root root 2015-09-12 03:31 5
dr-xr-xr-x root root 2015-09-12 03:31 50
dr-xr-xr-x system system 2015-09-12 03:31 590
dr-xr-xr-x root root 2015-09-12 03:31 64
dr-xr-xr-x root root 2015-09-12 03:31 65
dr-xr-xr-x root root 2015-09-12 03:31 66
dr-xr-xr-x media_rw media_rw 2015-09-12 03:31 666
dr-xr-xr-x root root 2015-09-12 03:31 67
dr-xr-xr-x root root 2015-09-12 03:31 68
dr-xr-xr-x root root 2015-09-12 03:31 69
dr-xr-xr-x u0_a24 u0_a24 2015-09-12 03:31 694
dr-xr-xr-x root root 2015-09-12 03:31 7
dr-xr-xr-x root root 2015-09-12 03:31 70
dr-xr-xr-x root root 2015-09-12 03:31 71
dr-xr-xr-x u0_a88 u0_a88 2015-09-14 06:14 7104
dr-xr-xr-x root root 2015-09-12 03:31 72
dr-xr-xr-x u0_a88 u0_a88 2015-09-14 06:15 7217
dr-xr-xr-x root root 2015-09-15 03:21 7221
dr-xr-xr-x root root 2015-09-12 03:31 73
dr-xr-xr-x root root 2015-09-12 03:31 74
dr-xr-xr-x root root 2015-09-15 03:21 7487
dr-xr-xr-x root root 2015-09-12 03:31 75
dr-xr-xr-x root root 2015-09-12 03:31 76
dr-xr-xr-x root root 2015-09-12 03:31 77
dr-xr-xr-x root root 2015-09-12 03:31 78
dr-xr-xr-x root root 2015-09-12 03:31 79
dr-xr-xr-x root root 2015-09-12 03:31 8
dr-xr-xr-x root root 2015-09-12 03:31 81
dr-xr-xr-x root root 2015-09-12 03:31 82
dr-xr-xr-x u0_a14 u0_a14 2015-09-15 02:45 8250
dr-xr-xr-x root root 2015-09-12 03:31 83
dr-xr-xr-x root root 2015-09-12 03:31 84
dr-xr-xr-x root root 2015-09-12 03:31 85
dr-xr-xr-x u0_a53 u0_a53 2015-09-13 11:39 8517
dr-xr-xr-x root root 2015-09-12 03:31 87
dr-xr-xr-x root root 2015-09-12 03:31 88
dr-xr-xr-x root root 2015-09-12 03:31 89
dr-xr-xr-x root root 2015-09-12 03:31 9
dr-xr-xr-x root root 2015-09-12 03:31 90
dr-xr-xr-x u0_a9 u0_a9 2015-09-12 03:31 903
dr-xr-xr-x root root 2015-09-12 03:31 91
dr-xr-xr-x u0_a9 u0_a9 2015-09-13 11:45 9159
dr-xr-xr-x root root 2015-09-12 03:31 93
dr-xr-xr-x u0_a66 u0_a66 2015-09-14 08:52 9356
dr-xr-xr-x root root 2015-09-12 03:31 94
dr-xr-xr-x root root 2015-09-12 03:31 95
dr-xr-xr-x root root 2015-09-12 03:31 97
dr-xr-xr-x root root 2015-09-12 03:31 98
dr-xr-xr-x root root 2015-09-12 03:31 99
dr-xr-xr-x root root 2015-09-15 03:24 asound
dr-xr-xr-x root root 2015-09-15 03:24 bluetooth
-r--r--r-- root root 0 2015-09-15 03:24 buddyinfo
dr-xr-xr-x root root 2015-09-15 03:24 bus
-r--r--r-- root root 0 2015-09-15 03:24 cgroups
-r--r----- root radio 0 2015-09-15 03:24 cmdline
-r--r--r-- root root 0 2015-09-15 03:24 consoles
-r--r--r-- root root 0 2015-09-15 03:24 cpuinfo
-r--r--r-- root root 0 2015-09-15 03:24 crypto
dr-xr-xr-x root root 2015-09-15 03:24 device-tree
-r--r--r-- root root 0 2015-09-15 03:24 devices
-r--r--r-- root root 0 2015-09-15 03:24 diskstats
dr-xr-xr-x root root 2015-09-15 03:24 driver
-r--r--r-- root root 0 2015-09-15 03:24 execdomains
-r--r--r-- root root 0 2015-09-15 03:24 fb
-r--r--r-- root root 0 2015-09-15 03:24 filesystems
dr-xr-xr-x root root 2015-09-15 03:24 fs
-r--r--r-- root root 0 2015-09-15 03:24 interrupts
-r--r--r-- root root 0 2015-09-15 03:24 iomem
-r--r--r-- root root 0 2015-09-15 03:24 ioports
dr-xr-xr-x root root 2015-09-15 03:24 irq
-r--r--r-- root root 0 2015-09-15 03:24 kallsyms
-r--r----- root system 0 2015-09-12 03:30 kmsg
-r-------- root root 0 2015-09-15 03:24 kpagecount
-r-------- root root 0 2015-09-15 03:24 kpageflags
-r--r--r-- root root 0 2015-09-15 03:24 loadavg
-r--r--r-- root root 0 2015-09-15 03:24 locks
-r--r--r-- root root 0 2015-09-15 03:24 meminfo
-r--r--r-- root root 0 2015-09-15 03:24 misc
lrwxrwxrwx root root 2015-09-15 03:24 mounts -> self/mounts
lrwxrwxrwx root root 2015-09-15 03:24 net -> self/net
-r--r--r-- root root 0 2015-09-15 03:24 pagetypeinfo
-r--r--r-- root root 0 2015-09-15 03:24 partitions
dr-xr-xr-x root root 2015-09-15 03:24 quadd
-r--r--r-- root root 0 2015-09-15 03:24 sched_debug
-r--r--r-- root root 0 2015-09-15 03:24 schedstat
dr-xr-xr-x root root 2015-09-15 03:24 scsi
lrwxrwxrwx root root 1969-12-31 16:00 self -> 10196
-r--r----- root log 0 2015-09-15 03:24 slabinfo
-r--r--r-- root root 0 2015-09-15 03:24 softirqs
-r--r--r-- root root 0 2015-09-15 03:24 stat
-r--r--r-- root root 0 2015-09-15 03:24 swaps
dr-xr-xr-x root root 2015-09-14 06:13 sys
lstat '/proc/sysrq-trigger' failed: Permission denied
dr-xr-xr-x root root 2015-09-15 03:24 sysvipc
-r--r--r-- root root 0 2015-09-15 03:24 timer_list
-rw-r--r-- root root 0 2015-09-15 03:24 timer_stats
dr-xr-xr-x root root 2015-09-15 03:24 tty
dr-xr-xr-x root root 2015-09-15 03:24 uid_cputime
dr-xr-xr-x root root 2015-09-15 03:24 uid_stat
-r--r--r-- root root 0 2015-09-15 03:24 uptime
-r--r--r-- root root 0 2015-09-15 03:24 version
-r--r----- root log 0 2015-09-15 03:24 vmallocinfo
-r--r--r-- root root 0 2015-09-15 03:24 vmstat
-r--r--r-- root root 0 2015-09-15 03:24 zoneinfo
If I list the the directory as my app process (using run-as [PACKAGE_NAME]):
shell@flounder:/ $ run-as my.packagename
shell@flounder:/data/data/my.packagename $ whoami
u0_a84
shell@flounder:/data/data/my.packagename $ /system/bin/toolbox ls -l /proc
lstat '/proc/1' failed: Permission denied
lstat '/proc/10' failed: Permission denied
lstat '/proc/101' failed: Permission denied
lstat '/proc/102' failed: Permission denied
lstat '/proc/103' failed: Permission denied
lstat '/proc/104' failed: Permission denied
dr-xr-xr-x u0_a15 u0_a15 2015-09-14 07:37 10451
lstat '/proc/105' failed: Permission denied
lstat '/proc/10570' failed: Permission denied
lstat '/proc/106' failed: Permission denied
lstat '/proc/107' failed: Permission denied
lstat '/proc/108' failed: Permission denied
lstat '/proc/11' failed: Permission denied
lstat '/proc/110' failed: Permission denied
lstat '/proc/111' failed: Permission denied
lstat '/proc/112' failed: Permission denied
lstat '/proc/113' failed: Permission denied
lstat '/proc/114' failed: Permission denied
lstat '/proc/115' failed: Permission denied
dr-xr-xr-x u0_a84 u0_a84 2015-09-15 03:26 11513
lstat '/proc/116' failed: Permission denied
lstat '/proc/117' failed: Permission denied
lstat '/proc/11719' failed: Permission denied
lstat '/proc/118' failed: Permission denied
lstat '/proc/119' failed: Permission denied
dr-xr-xr-x u0_a26 u0_a26 2015-09-12 03:31 1193
lstat '/proc/12' failed: Permission denied
lstat '/proc/120' failed: Permission denied
dr-xr-xr-x u0_a57 u0_a57 2015-09-12 03:31 1209
lstat '/proc/121' failed: Permission denied
lstat '/proc/122' failed: Permission denied
lstat '/proc/1227' failed: Permission denied
lstat '/proc/123' failed: Permission denied
lstat '/proc/1239' failed: Permission denied
lstat '/proc/124' failed: Permission denied
dr-xr-xr-x u0_a26 u0_a26 2015-09-12 03:31 1246
lstat '/proc/125' failed: Permission denied
lstat '/proc/126' failed: Permission denied
lstat '/proc/12696' failed: Permission denied
lstat '/proc/127' failed: Permission denied
lstat '/proc/128' failed: Permission denied
lstat '/proc/13' failed: Permission denied
dr-xr-xr-x u0_a26 u0_a26 2015-09-12 03:31 1305
lstat '/proc/132' failed: Permission denied
lstat '/proc/134' failed: Permission denied
dr-xr-xr-x u0_a86 u0_a86 2015-09-14 07:16 1343
lstat '/proc/135' failed: Permission denied
lstat '/proc/136' failed: Permission denied
lstat '/proc/137' failed: Permission denied
lstat '/proc/138' failed: Permission denied
lstat '/proc/139' failed: Permission denied
lstat '/proc/14' failed: Permission denied
lstat '/proc/140' failed: Permission denied
dr-xr-xr-x u0_a84 u0_a84 2015-09-15 03:29 14005
lstat '/proc/141' failed: Permission denied
lstat '/proc/142' failed: Permission denied
lstat '/proc/143' failed: Permission denied
lstat '/proc/144' failed: Permission denied
lstat '/proc/145' failed: Permission denied
lstat '/proc/149' failed: Permission denied
lstat '/proc/150' failed: Permission denied
lstat '/proc/153' failed: Permission denied
lstat '/proc/155' failed: Permission denied
lstat '/proc/16' failed: Permission denied
lstat '/proc/160' failed: Permission denied
lstat '/proc/163' failed: Permission denied
lstat '/proc/164' failed: Permission denied
lstat '/proc/165' failed: Permission denied
dr-xr-xr-x u0_a9 u0_a9 2015-09-12 03:31 1652
lstat '/proc/166' failed: Permission denied
lstat '/proc/17' failed: Permission denied
lstat '/proc/18227' failed: Permission denied
lstat '/proc/188' failed: Permission denied
lstat '/proc/192' failed: Permission denied
lstat '/proc/193' failed: Permission denied
lstat '/proc/194' failed: Permission denied
lstat '/proc/195' failed: Permission denied
lstat '/proc/2' failed: Permission denied
lstat '/proc/20' failed: Permission denied
dr-xr-xr-x u0_a19 u0_a19 2015-09-14 05:36 20564
lstat '/proc/207' failed: Permission denied
dr-xr-xr-x u0_a45 u0_a45 2015-09-15 03:00 20763
lstat '/proc/208' failed: Permission denied
lstat '/proc/21' failed: Permission denied
lstat '/proc/210' failed: Permission denied
lstat '/proc/215' failed: Permission denied
lstat '/proc/216' failed: Permission denied
lstat '/proc/217' failed: Permission denied
lstat '/proc/218' failed: Permission denied
lstat '/proc/219' failed: Permission denied
lstat '/proc/22' failed: Permission denied
lstat '/proc/220' failed: Permission denied
lstat '/proc/222' failed: Permission denied
lstat '/proc/223' failed: Permission denied
lstat '/proc/224' failed: Permission denied
lstat '/proc/225' failed: Permission denied
lstat '/proc/2258' failed: Permission denied
lstat '/proc/226' failed: Permission denied
lstat '/proc/227' failed: Permission denied
dr-xr-xr-x u0_a67 u0_a67 2015-09-15 03:15 2270
lstat '/proc/23' failed: Permission denied
lstat '/proc/24' failed: Permission denied
lstat '/proc/2428' failed: Permission denied
lstat '/proc/24353' failed: Permission denied
lstat '/proc/25' failed: Permission denied
lstat '/proc/25597' failed: Permission denied
lstat '/proc/26' failed: Permission denied
lstat '/proc/26671' failed: Permission denied
lstat '/proc/27' failed: Permission denied
dr-xr-xr-x u0_a84 u0_a84 2015-09-15 03:15 2738
lstat '/proc/28' failed: Permission denied
lstat '/proc/29' failed: Permission denied
lstat '/proc/3' failed: Permission denied
lstat '/proc/30' failed: Permission denied
lstat '/proc/30095' failed: Permission denied
dr-xr-xr-x u0_a18 u0_a18 2015-09-15 03:11 30266
dr-xr-xr-x u0_a40 u0_a40 2015-09-15 03:11 30290
lstat '/proc/30333' failed: Permission denied
dr-xr-xr-x u0_a37 u0_a37 2015-09-15 03:11 30382
dr-xr-xr-x u0_a77 u0_a77 2015-09-15 03:11 30420
dr-xr-xr-x u0_a61 u0_a61 2015-09-15 03:11 30458
lstat '/proc/30729' failed: Permission denied
dr-xr-xr-x u0_a4 u0_a4 2015-09-14 11:12 30994
lstat '/proc/31' failed: Permission denied
dr-xr-xr-x u0_a9 u0_a9 2015-09-14 13:31 31453
lstat '/proc/31844' failed: Permission denied
lstat '/proc/32' failed: Permission denied
dr-xr-xr-x u0_a6 u0_a6 2015-09-15 01:13 32176
lstat '/proc/32422' failed: Permission denied
lstat '/proc/32476' failed: Permission denied
lstat '/proc/32552' failed: Permission denied
lstat '/proc/33' failed: Permission denied
lstat '/proc/47' failed: Permission denied
lstat '/proc/48' failed: Permission denied
lstat '/proc/49' failed: Permission denied
lstat '/proc/5' failed: Permission denied
lstat '/proc/50' failed: Permission denied
lstat '/proc/590' failed: Permission denied
lstat '/proc/64' failed: Permission denied
lstat '/proc/65' failed: Permission denied
lstat '/proc/66' failed: Permission denied
lstat '/proc/666' failed: Permission denied
lstat '/proc/67' failed: Permission denied
lstat '/proc/68' failed: Permission denied
lstat '/proc/69' failed: Permission denied
lstat '/proc/694' failed: Permission denied
lstat '/proc/7' failed: Permission denied
lstat '/proc/70' failed: Permission denied
lstat '/proc/71' failed: Permission denied
dr-xr-xr-x u0_a88 u0_a88 2015-09-14 06:14 7104
lstat '/proc/72' failed: Permission denied
dr-xr-xr-x u0_a88 u0_a88 2015-09-14 06:15 7217
lstat '/proc/7221' failed: Permission denied
lstat '/proc/73' failed: Permission denied
lstat '/proc/74' failed: Permission denied
lstat '/proc/7487' failed: Permission denied
lstat '/proc/75' failed: Permission denied
lstat '/proc/76' failed: Permission denied
lstat '/proc/77' failed: Permission denied
lstat '/proc/78' failed: Permission denied
lstat '/proc/79' failed: Permission denied
lstat '/proc/8' failed: Permission denied
lstat '/proc/81' failed: Permission denied
lstat '/proc/82' failed: Permission denied
dr-xr-xr-x u0_a14 u0_a14 2015-09-15 02:45 8250
lstat '/proc/83' failed: Permission denied
lstat '/proc/84' failed: Permission denied
lstat '/proc/85' failed: Permission denied
dr-xr-xr-x u0_a53 u0_a53 2015-09-13 11:39 8517
lstat '/proc/87' failed: Permission denied
lstat '/proc/88' failed: Permission denied
lstat '/proc/89' failed: Permission denied
lstat '/proc/9' failed: Permission denied
lstat '/proc/90' failed: Permission denied
dr-xr-xr-x u0_a9 u0_a9 2015-09-12 03:31 903
lstat '/proc/91' failed: Permission denied
dr-xr-xr-x u0_a9 u0_a9 2015-09-13 11:45 9159
lstat '/proc/93' failed: Permission denied
dr-xr-xr-x u0_a66 u0_a66 2015-09-14 08:52 9356
lstat '/proc/94' failed: Permission denied
lstat '/proc/95' failed: Permission denied
lstat '/proc/97' failed: Permission denied
lstat '/proc/98' failed: Permission denied
lstat '/proc/99' failed: Permission denied
dr-xr-xr-x root root 2015-09-15 03:29 asound
dr-xr-xr-x root root 2015-09-15 03:29 bluetooth
-r--r--r-- root root 0 2015-09-15 03:29 buddyinfo
dr-xr-xr-x root root 2015-09-15 03:29 bus
-r--r--r-- root root 0 2015-09-15 03:29 cgroups
-r--r----- root radio 0 2015-09-15 03:29 cmdline
-r--r--r-- root root 0 2015-09-15 03:29 consoles
-r--r--r-- root root 0 2015-09-15 03:29 cpuinfo
-r--r--r-- root root 0 2015-09-15 03:29 crypto
dr-xr-xr-x root root 2015-09-15 03:29 device-tree
-r--r--r-- root root 0 2015-09-15 03:29 devices
-r--r--r-- root root 0 2015-09-15 03:29 diskstats
dr-xr-xr-x root root 2015-09-15 03:29 driver
-r--r--r-- root root 0 2015-09-15 03:29 execdomains
-r--r--r-- root root 0 2015-09-15 03:29 fb
-r--r--r-- root root 0 2015-09-15 03:29 filesystems
dr-xr-xr-x root root 2015-09-15 03:29 fs
-r--r--r-- root root 0 2015-09-15 03:29 interrupts
-r--r--r-- root root 0 2015-09-15 03:29 iomem
-r--r--r-- root root 0 2015-09-15 03:29 ioports
dr-xr-xr-x root root 2015-09-15 03:29 irq
-r--r--r-- root root 0 2015-09-15 03:29 kallsyms
-r--r----- root system 0 2015-09-12 03:30 kmsg
-r-------- root root 0 2015-09-15 03:29 kpagecount
-r-------- root root 0 2015-09-15 03:29 kpageflags
-r--r--r-- root root 0 2015-09-15 03:29 loadavg
-r--r--r-- root root 0 2015-09-15 03:29 locks
-r--r--r-- root root 0 2015-09-15 03:29 meminfo
-r--r--r-- root root 0 2015-09-15 03:29 misc
lrwxrwxrwx root root 2015-09-15 03:29 mounts -> self/mounts
lrwxrwxrwx root root 2015-09-15 03:29 net -> self/net
-r--r--r-- root root 0 2015-09-15 03:29 pagetypeinfo
-r--r--r-- root root 0 2015-09-15 03:29 partitions
dr-xr-xr-x root root 2015-09-15 03:29 quadd
-r--r--r-- root root 0 2015-09-15 03:29 sched_debug
-r--r--r-- root root 0 2015-09-15 03:29 schedstat
dr-xr-xr-x root root 2015-09-15 03:29 scsi
lrwxrwxrwx root root 1969-12-31 16:00 self -> 14005
-r--r----- root log 0 2015-09-15 03:29 slabinfo
-r--r--r-- root root 0 2015-09-15 03:29 softirqs
-r--r--r-- root root 0 2015-09-15 03:29 stat
-r--r--r-- root root 0 2015-09-15 03:29 swaps
dr-xr-xr-x root root 2015-09-14 06:13 sys
lstat '/proc/sysrq-trigger' failed: Permission denied
dr-xr-xr-x root root 2015-09-15 03:29 sysvipc
-r--r--r-- root root 0 2015-09-15 03:29 timer_list
-rw-r--r-- root root 0 2015-09-15 03:29 timer_stats
dr-xr-xr-x root root 2015-09-15 03:29 tty
dr-xr-xr-x root root 2015-09-15 03:29 uid_cputime
dr-xr-xr-x root root 2015-09-15 03:29 uid_stat
-r--r--r-- root root 0 2015-09-15 03:29 uptime
-r--r--r-- root root 0 2015-09-15 03:29 version
-r--r----- root log 0 2015-09-15 03:29 vmallocinfo
-r--r--r-- root root 0 2015-09-15 03:29 vmstat
-r--r--r-- root root 0 2015-09-15 03:29 zoneinfo
Obviously, the files that I received a "Permission denied" error on cannot be read using new java.io.File("/proc").listFiles(); either.
My question:
Why can't my application process read these directories? The permissions give "other" users read access ("dr-xr-xr-x").
回答1:
Android 5 and above use SELinux which uses two forms of access control. Traditional Linux uses a Discretionary Access Control List. The SE component also enforces a Mandatory Access Control List. The former is default allow, the latter is default deny.
You, or a process, only have access to an object if both sets of permissions allow you. Access is determined by SE contexts. Shell and app contexts have different permissions, and unfortunately there isn't any known way to give an app shell context.
You can view Security Contexts using:
ls -Z
I don't have a Marshmallow device to test, however what might give your app the necessary context is getting the usagestatsmanager permission. A user would have to enable it security settings, and I'm told Samsung devices don't have the necessary menu. Shot in the dark mind you.
If you want to try it, see this question: How to check if "android.permission.PACKAGE_USAGE_STATS" permission is given?
This page might give you more info on permissions: https://su.chainfire.eu/#selinux
来源：https://stackoverflow.com/questions/32584063/android-file-permissions-on-android-6-0