C/C++: Printing Stack Trace with printstack() on Solaris

libc on Solaris 9 and later, provides a useful function called printstack, to print a symbolic stack trace to the specified file descriptor. This is useful for reporting errors from an application during run-time.

If the stack trace appears corrupted, or if the stack cannot be read, printstack() returns -1.

Programmatic example:

% more printstack.c
#include <stdio.h>
#include <ucontext.h>

int callee(int file) {
        printstack(file);
        return (0);
}

int caller() {
        int a;
        a = callee (fileno(stdout));
        return (a);
}

int main() {
        caller();
        return (0);
}

% cc -o stacktrace stacktrace.c
% ./stacktrace
/tmp/stacktrace:callee+0x18
/tmp/stacktrace:caller+0x22
/tmp/stacktrace:main+0x14
/tmp/stacktrace:0x6d2

The printstack() function uses dladdr1() to obtain symbolic symbol names. As a result, only global symbols are reported as symbol names by printstack().

% CC -o stacktrace stacktrace.c
% ./stacktrace
/tmp/stacktrace:__1cGcallee6Fi_i_+0x18
/tmp/stacktrace:__1cGcaller6F_i_+0x22
/tmp/stacktrace:main+0x14
/tmp/stacktrace:0x91a

The stack trace from a C++ program, will have all the symbols in their mangled form. So as of now, the programmers may need to have their own wrapper functions to print the stack trace in unmangled form.

There has been an RFE (Request For Enhancement) in place against Solaris' libc to print the stack trace in unmangled form, when printstack() has been called from a C++ program. This will be released as a libc patch for Solaris 8, 9 & 10 some time in the near future.

% elfdump -CsN.symtab libc.so | grep printstack
    [5275]  0x00052629 0x00000051  FUNC GLOB  D    0 .text       _printstack
    [6332]  0x00052629 0x00000051  FUNC WEAK  D    0 .text       printstack

Since the object code is automatically linked with libc during the creation of an executable or a dynamic library, the programmer need not specify -lc on the compile line.

Suggested Reading:
Man page of walkcontext or printstack