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The [Linux] VirtualMemory Map (as seen by a [UserSpace] program) | __Starts at__ | __Contains__ | ffffffff |< End of the universe | ffffe000 |< vsyscall table (new in 2.5.x) | c0000000 |< Off limits, reserved for the kernel | bfffffff |< Process stack (grows down) | bffff000 |< Process heap (grows up) | 40000000 |< Libraries | zzzzzzzz |< Unused | yyyyyyyy |< __.[bss|BSS]__ segment, uninitialised program data | xxxxxxxx |< __.data__ segment, initialised program data | 08048000 |< __.text__ segment, program code | 00000000 |< Unmapped to trap [NULL] pointers !!Practical examples !Library-mapped memory (using ldd(1)) $ ldd /bin/ls librt.so.1 => /lib/librt.so.1 (0x40026000) libc.so.6 => /lib/libc.so.6 (0x40038000) libpthread.so.0 => /lib/libpthread.so.0 (0x4016a000) /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000) !Program code $ cat > x.c #include <stdio.h> int main(void) {printf("%p\n", main);return 0;} $ gcc -o x x.c && ./x 0x8048344 $ (this is printing the address of the main function.) !Process Heap $ cat > x2.c #include <stdio.h> int main(void) {char c;printf("%p\n", &c); return 0;} $ gcc -o x2 x2.c && ./x2 0xbffffab7 !Process Data and bss segment $ perl -e 'my $var; print \$var . "\n"' SCALAR(0x814f38c) (note that this is the address in the [Perl] interpreter) $ cat > x3.c #include <stdio.h> #include <stdlib.h> int main(void) {char *p=!malloc(3);printf("%p\n", p); return 0;} $ gcc -o x3 x3.c && ./x3 0x8049628 Also, cat /proc/''pid''/maps gives you the memory map for a program :)
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