05-13-2008
Note that it's not a stack overflow bug but the fact that sprintf() does not check for bounds which causes the routine to overflow its frame.
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
hello all,
I tried a program on an array to intialise array elements from the standard input device.it is an integer array of 5 elements.but after entering the 4th element it throws a message called "Segmentation Fault" and returns to the command prompt without asking for the 5th element.
... (3 Replies)
Discussion started by: compbug
3 Replies
2. Programming
I have written a program which takes a directory as command line arguments and displays all the dir and files in it.
I don't know why I have a problem with the /etc directory.It displays all the directories and files untill it reaches a sub directory called peers which is in /etc/ppp/peers.the... (4 Replies)
Discussion started by: vijlak
4 Replies
3. Programming
ive written my code in C for implementation of a simple lexical analyser using singly linked list hence am making use of dynamic allocation,but when run in linux it gives a segmentation fault is it cause of the malloc function that ive made use of????any suggestions as to what i could do???
thank... (8 Replies)
Discussion started by: rockgal
8 Replies
4. AIX
Hi ,
During execution a backup binary i get following error
"Program error 11 (Segmentation fault), saving core file in '/usr/datatools"
Riyaz (2 Replies)
Discussion started by: rshaikh
2 Replies
5. UNIX for Dummies Questions & Answers
Hi,
While comparing primary key data of two tables thr bteq script I am getting this Error. This script is a shell script.
*** Error: The following error was encountered on the output file.
Script.sh: 3043492 Segmentation fault(coredump)
Please let me know how to get through it.
... (5 Replies)
Discussion started by: monika
5 Replies
6. Programming
Hi,
I am having this segmentation fault not in the following program, bt. in my lab program . My lab program is horrible long so cannot post it here bt. I am using the following logic in my program which is giving the segmentation fault. Bt. if I run this sample program as it is it dosen't give... (3 Replies)
Discussion started by: mind@work
3 Replies
7. Programming
I use a binary name (ie polo) it gets some parameter , so for debugging normally i do this :
i wrote script for watchdog my app (polo) and check every second if it's not running then start it , the problem is , if my app , remain in state of segmentation fault for a while (ie 15 ... (6 Replies)
Discussion started by: pooyair
6 Replies
8. Homework & Coursework Questions
this is a network programming code to run a rock paper scissors in a client and server.
I completed it and it was working without any error. After I added the findWinner function to the server code it starts giving me segmentation fault.
-the segmentation fault is fixed
Current problem -Also... (3 Replies)
Discussion started by: femchi
3 Replies
9. Programming
I keep getting this fault on a lot of the codes I write, I'm not exactly sure why so I'd really appreciate it if someone could explain the idea to me.
For example this code
#include <stdio.h>
main()
{
unsigned long a=0;
unsigned long b=0;
int z;
{
printf("Enter two... (2 Replies)
Discussion started by: sizzler786
2 Replies
10. Programming
Oddities with gcc, 2.95.3 for the AMIGA and 4.2.1 for MY current OSX 10.14.1...
I am creating a basic calculator for the AMIGA ADE *NIX emulator in C as it does not have one.
Below are two very condensed snippets of which I have added the results inside the each code section.
IMPORTANT!... (11 Replies)
Discussion started by: wisecracker
11 Replies
ALLOCA(3) Linux Programmer's Manual ALLOCA(3)
NAME
alloca - allocate memory that is automatically freed
SYNOPSIS
#include <alloca.h>
void *alloca(size_t size);
DESCRIPTION
The alloca() function allocates size bytes of space in the stack frame of the caller. This temporary space is automatically freed when the
function that called alloca() returns to its caller.
RETURN VALUE
The alloca() function returns a pointer to the beginning of the allocated space. If the allocation causes stack overflow, program behavior
is undefined.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
+----------+---------------+---------+
|Interface | Attribute | Value |
+----------+---------------+---------+
|alloca() | Thread safety | MT-Safe |
+----------+---------------+---------+
CONFORMING TO
This function is not in POSIX.1.
There is evidence that the alloca() function appeared in 32V, PWB, PWB.2, 3BSD, and 4BSD. There is a man page for it in 4.3BSD. Linux
uses the GNU version.
NOTES
The alloca() function is machine- and compiler-dependent. For certain applications, its use can improve efficiency compared to the use of
malloc(3) plus free(3). In certain cases, it can also simplify memory deallocation in applications that use longjmp(3) or siglongjmp(3).
Otherwise, its use is discouraged.
Because the space allocated by alloca() is allocated within the stack frame, that space is automatically freed if the function return is
jumped over by a call to longjmp(3) or siglongjmp(3).
Do not attempt to free(3) space allocated by alloca()!
Notes on the GNU version
Normally, gcc(1) translates calls to alloca() with inlined code. This is not done when either the -ansi, -std=c89, -std=c99, or the
-std=c11 option is given and the header <alloca.h> is not included. Otherwise, (without an -ansi or -std=c* option) the glibc version of
<stdlib.h> includes <alloca.h> and that contains the lines:
#ifdef __GNUC__
#define alloca(size) __builtin_alloca (size)
#endif
with messy consequences if one has a private version of this function.
The fact that the code is inlined means that it is impossible to take the address of this function, or to change its behavior by linking
with a different library.
The inlined code often consists of a single instruction adjusting the stack pointer, and does not check for stack overflow. Thus, there is
no NULL error return.
BUGS
There is no error indication if the stack frame cannot be extended. (However, after a failed allocation, the program is likely to receive
a SIGSEGV signal if it attempts to access the unallocated space.)
On many systems alloca() cannot be used inside the list of arguments of a function call, because the stack space reserved by alloca() would
appear on the stack in the middle of the space for the function arguments.
SEE ALSO
brk(2), longjmp(3), malloc(3)
COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
GNU
2017-09-15 ALLOCA(3)