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authorRob Landley <rob@landley.net>2006-04-19 01:21:43 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-04-19 12:13:51 -0400
commit966a082f80a073af1564c5ed6313ef2f0587dde3 (patch)
treeda199abad4c035c60f04100b2759815655f46f31 /arch/um
parentf983c45ebedcaf686223afaecd8e681e8dcd15a9 (diff)
[PATCH] uml: physical memory map file fixes
UML really wants shared memory semantics form its physical memory map file, and the place for that is /dev/shm. So move the default, and fix the error messages to recognize that this value can be overridden. Signed-off-by: Rob Landley <rob@landley.net> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/os-Linux/mem.c118
-rw-r--r--arch/um/os-Linux/start_up.c24
2 files changed, 118 insertions, 24 deletions
diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c
index 71bb90a7606d..c6432e729241 100644
--- a/arch/um/os-Linux/mem.c
+++ b/arch/um/os-Linux/mem.c
@@ -8,6 +8,7 @@
8#include <fcntl.h> 8#include <fcntl.h>
9#include <sys/types.h> 9#include <sys/types.h>
10#include <sys/mman.h> 10#include <sys/mman.h>
11#include <sys/statfs.h>
11#include "kern_util.h" 12#include "kern_util.h"
12#include "user.h" 13#include "user.h"
13#include "user_util.h" 14#include "user_util.h"
@@ -19,6 +20,7 @@
19 20
20#include <sys/param.h> 21#include <sys/param.h>
21 22
23static char *default_tmpdir = "/tmp";
22static char *tempdir = NULL; 24static char *tempdir = NULL;
23 25
24static void __init find_tempdir(void) 26static void __init find_tempdir(void)
@@ -34,7 +36,7 @@ static void __init find_tempdir(void)
34 break; 36 break;
35 } 37 }
36 if((dir == NULL) || (*dir == '\0')) 38 if((dir == NULL) || (*dir == '\0'))
37 dir = "/tmp"; 39 dir = default_tmpdir;
38 40
39 tempdir = malloc(strlen(dir) + 2); 41 tempdir = malloc(strlen(dir) + 2);
40 if(tempdir == NULL){ 42 if(tempdir == NULL){
@@ -46,6 +48,96 @@ static void __init find_tempdir(void)
46 strcat(tempdir, "/"); 48 strcat(tempdir, "/");
47} 49}
48 50
51/* This will return 1, with the first character in buf being the
52 * character following the next instance of c in the file. This will
53 * read the file as needed. If there's an error, -errno is returned;
54 * if the end of the file is reached, 0 is returned.
55 */
56static int next(int fd, char *buf, int size, char c)
57{
58 int n;
59 char *ptr;
60
61 while((ptr = strchr(buf, c)) == NULL){
62 n = read(fd, buf, size - 1);
63 if(n == 0)
64 return 0;
65 else if(n < 0)
66 return -errno;
67
68 buf[n] = '\0';
69 }
70
71 ptr++;
72 memmove(buf, ptr, strlen(ptr) + 1);
73 return 1;
74}
75
76static int checked_tmpdir = 0;
77
78/* Look for a tmpfs mounted at /dev/shm. I couldn't find a cleaner
79 * way to do this than to parse /proc/mounts. statfs will return the
80 * same filesystem magic number and fs id for both /dev and /dev/shm
81 * when they are both tmpfs, so you can't tell if they are different
82 * filesystems. Also, there seems to be no other way of finding the
83 * mount point of a filesystem from within it.
84 *
85 * If a /dev/shm tmpfs entry is found, then we switch to using it.
86 * Otherwise, we stay with the default /tmp.
87 */
88static void which_tmpdir(void)
89{
90 int fd, found;
91 char buf[128] = { '\0' };
92
93 if(checked_tmpdir)
94 return;
95
96 checked_tmpdir = 1;
97
98 printf("Checking for tmpfs mount on /dev/shm...");
99
100 fd = open("/proc/mounts", O_RDONLY);
101 if(fd < 0){
102 printf("failed to open /proc/mounts, errno = %d\n", errno);
103 return;
104 }
105
106 while(1){
107 found = next(fd, buf, sizeof(buf) / sizeof(buf[0]), ' ');
108 if(found != 1)
109 break;
110
111 if(!strncmp(buf, "/dev/shm", strlen("/dev/shm")))
112 goto found;
113
114 found = next(fd, buf, sizeof(buf) / sizeof(buf[0]), '\n');
115 if(found != 1)
116 break;
117 }
118
119err:
120 if(found == 0)
121 printf("nothing mounted on /dev/shm\n");
122 else if(found < 0)
123 printf("read returned errno %d\n", -found);
124
125 return;
126
127found:
128 found = next(fd, buf, sizeof(buf) / sizeof(buf[0]), ' ');
129 if(found != 1)
130 goto err;
131
132 if(strncmp(buf, "tmpfs", strlen("tmpfs"))){
133 printf("not tmpfs\n");
134 return;
135 }
136
137 printf("OK\n");
138 default_tmpdir = "/dev/shm";
139}
140
49/* 141/*
50 * This proc still used in tt-mode 142 * This proc still used in tt-mode
51 * (file: kernel/tt/ptproxy/proxy.c, proc: start_debugger). 143 * (file: kernel/tt/ptproxy/proxy.c, proc: start_debugger).
@@ -56,6 +148,7 @@ int make_tempfile(const char *template, char **out_tempname, int do_unlink)
56 char *tempname; 148 char *tempname;
57 int fd; 149 int fd;
58 150
151 which_tmpdir();
59 tempname = malloc(MAXPATHLEN); 152 tempname = malloc(MAXPATHLEN);
60 153
61 find_tempdir(); 154 find_tempdir();
@@ -137,3 +230,26 @@ int create_mem_file(unsigned long long len)
137 } 230 }
138 return(fd); 231 return(fd);
139} 232}
233
234
235void check_tmpexec(void)
236{
237 void *addr;
238 int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);
239
240 addr = mmap(NULL, UM_KERN_PAGE_SIZE,
241 PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
242 printf("Checking PROT_EXEC mmap in %s...",tempdir);
243 fflush(stdout);
244 if(addr == MAP_FAILED){
245 err = errno;
246 perror("failed");
247 if(err == EPERM)
248 printf("%s must be not mounted noexec\n",tempdir);
249 exit(1);
250 }
251 printf("OK\n");
252 munmap(addr, UM_KERN_PAGE_SIZE);
253
254 close(fd);
255}
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index 387e26af301a..503148504009 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -296,29 +296,7 @@ static void __init check_ptrace(void)
296 check_sysemu(); 296 check_sysemu();
297} 297}
298 298
299extern int create_tmp_file(unsigned long long len); 299extern void check_tmpexec(void);
300
301static void check_tmpexec(void)
302{
303 void *addr;
304 int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);
305
306 addr = mmap(NULL, UM_KERN_PAGE_SIZE,
307 PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE, fd, 0);
308 printf("Checking PROT_EXEC mmap in /tmp...");
309 fflush(stdout);
310 if(addr == MAP_FAILED){
311 err = errno;
312 perror("failed");
313 if(err == EPERM)
314 printf("/tmp must be not mounted noexec\n");
315 exit(1);
316 }
317 printf("OK\n");
318 munmap(addr, UM_KERN_PAGE_SIZE);
319
320 close(fd);
321}
322 300
323void os_early_checks(void) 301void os_early_checks(void)
324{ 302{