Bug 2249
| Summary: | mktemp fails (it does nothing) | ||
|---|---|---|---|
| Product: | [Retired] Red Hat Linux | Reporter: | jay |
| Component: | glibc | Assignee: | Cristian Gafton <gafton> |
| Status: | CLOSED WONTFIX | QA Contact: | |
| Severity: | high | Docs Contact: | |
| Priority: | high | ||
| Version: | 6.0 | CC: | jay |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | i386 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 1999-07-02 20:59:10 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
This issue has been forwarded to a developer for further action. You are using mktemp incorrectly. It expects 6 X's to be passed. It may also fail so you should check the return code mktemp /tmp/foo.XXXXXX works for me ------- Email Received From James Youngman <jay> 06/17/99 00:37 ------- Confirmed. Looks like a tiny glibc bug wants fixing. Contents of the mail message:
Oops. The original bug report was for mktemp(3), not mktemp(1).
Well, as Alan pointed out, I had miscounted the Xs in the
function argument. However, there is still a bug. Where the argument
does not end in SIX 'X' characters, the function fails to return NULL.
Here is a much simpler example:-
[james@periwinkle james]$ make mktemp-test
cc mktemp-test.c -o mktemp-test
[james@periwinkle james]$ ./mktemp-test
mktemp returns '' (0xbffff798)
[james@periwinkle james]$ cat mktemp-test.c
#include <stdio.h>
#include <stdlib.h>
int main()
{
char tmp[] = "/tmp/test.XXXXX"; /* Note! only 5 Xs! */
char * p = mktemp(tmp);
printf("mktemp returns '%s' (%p)\n", p ? p : "NULL", (void*)p);
return 0;
}
[james@periwinkle james]$ cat /etc/redhat-release
Red Hat Linux release 6.0 (Hedwig)
[james@periwinkle james]$
From the manpage:-
RETURN VALUE
The mktemp() function returns NULL on error (template did
not end in XXXXXX) and template otherwise.
[...]
Well, POSIX says:
RETURN VALUE
The mktemp() function returns the pointer template. If a unique
name cannot be created, template points to a null string.
[...]
So the current operation is correct. The man page will be fixed to
reflect that.
|
mktemp returns an empty string. Here is a GDB session showing this:- (gdb) b main Breakpoint 1 at 0x804913c: file ../../gnu/CSSC/bsd/sccs.c, line 576. (gdb) r unedit foo Starting program: /home/james/source/CSSC/compile/bsd/sccs unedit foo Breakpoint 1, main (argc=3, argv=0xbffffad4) at ../../gnu/CSSC/bsd/sccs.c:576 (gdb) n (gdb) (gdb) (gdb) (gdb) [...] (gdb) (gdb) (gdb) s command (argv=0xbffffad8, forkflag=0 '\000', arg0=0x804b17e "") at ../../gnu/CSSC/bsd/sccs.c:943 (gdb) n (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) s unedit (fn=0xbffffc42 "foo") at ../../gnu/CSSC/bsd/sccs.c:1862 (gdb) n (gdb) (gdb) print tfn $1 = "/tmp/sccsXXXXX" (gdb) n (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) (gdb) print tfn $2 = "\000tmp/sccsXXXXX" (gdb) list 1890 return (FALSE); 1891 } 1892 1893 /* create temp file for editing p-file */ 1894 mktemp (tfn); 1895 tfp = fopen (tfn, "w"); 1896 if (tfp == NULL) 1897 { 1898 usrerr ("cannot create \"%s\"", tfn); 1899 fclose(pfp); (gdb) where #0 unedit (fn=0xbffffc42 "foo") at ../../gnu/CSSC/bsd/sccs.c:1895 #1 0x8049a57 in command (argv=0xbffffad8, forkflag=0 '\000', arg0=0x804b17e "") at ../../gnu/CSSC/bsd/sccs.c:1103 #2 0x80494d0 in main (argc=3, argv=0xbffffad8) at ../../gnu/CSSC/bsd/sccs.c:779 #3 0x40033ca7 in __libc_start_main (main=0x8049130 <main>, argc=3, argv=0xbffffad4, init=0x8048b24 <_init>, fini=0x804ad7c <_fini>, rtld_fini=0x40009c30 <_dl_fini>, stack_end=0xbffffacc) at ../sysdeps/generic/libc-start.c:78 (gdb) quit Here is the strace output of the same event (which includes the complete program execution):- execve("../../bsd/sccs", ["../../bsd/sccs", "unedit", "foo"], [/* 36 vars */]) = 0 brk(0) = 0x804ce19 open("/etc/ld.so.preload", O_RDONLY) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 4 fstat(4, {st_mode=0, st_size=0, ...}) = 0 mmap(0, 34588, PROT_READ, MAP_PRIVATE, 4, 0) = 0x40013000 close(4) = 0 open("/lib/libc.so.6", O_RDONLY) = 4 fstat(4, {st_mode=0, st_size=0, ...}) = 0 read(4, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3"..., 4096) = 4096 mmap(0, 944824, PROT_READ|PROT_EXEC, MAP_PRIVATE, 4, 0) = 0x4001c000 mprotect(0x400fb000, 31416, PROT_NONE) = 0 mmap(0x400fb000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 4, 0xde000) = 0x400fb000 mmap(0x40100000, 10936, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOU S, -1, 0) = 0x40100000 close(4) = 0 mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x401030 00 munmap(0x40013000, 34588) = 0 personality(PER_LINUX) = 0 getpid() = 1363 getuid() = 101 geteuid() = 101 getgid() = 100 getegid() = 100 brk(0) = 0x804ce19 brk(0x804ce51) = 0x804ce51 brk(0x804d000) = 0x804d000 open("/usr/share/locale/locale.alias", O_RDONLY) = 4 fstat(4, {st_mode=S_ISGID|S_ISVTX|0615, st_size=0, ...}) = 0 mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x400130 00 read(4, "# Locale name alias data base.\n"..., 4096) = 2096 brk(0x804e000) = 0x804e000 read(4, "", 4096) = 0 close(4) = 0 munmap(0x40013000, 4096) = 0 open("/usr/share/i18n/locale.alias", O_RDONLY) = -1 ENOENT (No such file or dire ctory) open("/usr/share/locale/en_GB/LC_MESSAGES", O_RDONLY) = 4 fstat(4, {st_mode=0, st_size=0, ...}) = 0 close(4) = 0 open("/usr/share/locale/en_GB/LC_MESSAGES/SYS_LC_MESSAGES", O_RDONLY) = 4 fstat(4, {st_mode=0, st_size=0, ...}) = 0 mmap(0, 42, PROT_READ, MAP_PRIVATE, 4, 0) = 0x40013000 close(4) = 0 open("/usr/share/locale/en_GB/LC_MONETARY", O_RDONLY) = 4 fstat(4, {st_mode=0, st_size=0, ...}) = 0 mmap(0, 93, PROT_READ, MAP_PRIVATE, 4, 0) = 0x40014000 close(4) = 0 open("/usr/share/locale/en_GB/LC_COLLATE", O_RDONLY) = 4 fstat(4, {st_mode=S_IFCHR|S_ISUID|S_ISGID|0535, st_rdev=makedev(232, 171), ...}) = 0 mmap(0, 29970, PROT_READ, MAP_PRIVATE, 4, 0) = 0x40104000 close(4) = 0 open("/usr/share/locale/en_GB/LC_TIME", O_RDONLY) = 4 fstat(4, {st_mode=S_ISVTX|0406, st_size=0, ...}) = 0 mmap(0, 492, PROT_READ, MAP_PRIVATE, 4, 0) = 0x40015000 close(4) = 0 open("/usr/share/locale/en_GB/LC_NUMERIC", O_RDONLY) = 4 fstat(4, {st_mode=S_IFCHR|S_ISUID|S_ISGID|067, st_rdev=makedev(232, 171), ...}) = 0 mmap(0, 27, PROT_READ, MAP_PRIVATE, 4, 0) = 0x40016000 close(4) = 0 brk(0x804f000) = 0x804f000 open("/usr/share/locale/en_GB/LC_CTYPE", O_RDONLY) = 4 fstat(4, {st_mode=0, st_size=0, ...}) = 0 mmap(0, 10428, PROT_READ, MAP_PRIVATE, 4, 0) = 0x40017000 close(4) = 0 stat("foo", {st_mode=0, st_size=0, ...}) = 0 open("SCCS/p.foo", O_RDONLY) = 4 open("", O_WRONLY|O_CREAT|O_TRUNC, 0666) = -1 ENOENT (No such file or directory) write(2, "\nsccs: ", 7) = 7 write(2, "cannot create \"\"", 16) = 16 write(2, "\n", 1) = 1 close(4) = 0 _exit(71) = ? Obviously, it's the open("",...) which is the symptom. Unsetting $LANG doesn't help.