PSTACK_ITER(3PROC) Process Control Library Functions PSTACK_ITER(3PROC)

Pstack_iter
iterate process stack frames

Process Control Library (libproc, -lproc)

#include <libproc.h>

int
Pstack_iter(struct ps_prochandle *P, const prgregset_t regs, proc_stack_f *func, void *data);

The Pstack_iter() function iterates over the stack frames in the process P starting at the point defined by regs.

For each valid stack frame encountered, the callback function func is invoked with data passed as argument. The full signature of proc_stack_f is defined in libproc(3LIB). With each callback, a register set, argument set, and argument count will be provided. In that register set, only a subset of the registers will be valid, which include the frame pointer, program counter, and on SPARC systems, the next program counter. These registers can be accessed with the constants R_FP, R_PC, and R_nPC respectively. These correspond to the registers %ebp and %eip on i386, %rbp and %rip on amd64, %fp, %pc, and %npc on both SPARC and SPARCv9.

Callers will receive a callback for the first stack frame indicated by regs and then will receive a subsequent callback for each caller of that frame until no such frame can be found. Stack frames that logically come after the frame indicated by regs will not receive callbacks.

The compiler can either facilitate or stymie the iteration of the stack. Programs that have been compiled in such a way as to omit the frame pointer will result in truncated stacks. Similarly, if the initial set of registers passed in via regs is invalid, then the ability to iterate the stack will be limited. The return value of func controls whether or not iteration continues. If func returns 0 then iteration continues. However, if func returns non-zero, then iteration will halt and that value will be used as the return value of the Pstack_iter() function. Because Pstack_iter() returns -1 on internal failure it is recommended the callback function not return -1 to indicate an error. Thus the caller may distinguish between the failure of the callback function and the failure of the Pstack_iter() function.

Upon successful completion, the Pstack_iter() function returns 0. If there was an internal error then -1 is returned. Otherwise, if the callback function func returns non-zero, then its return value will be returned instead.

Uncommitted

See LOCKING in libproc(3LIB).

libproc(3LIB), proc(5)
May 11, 2016 OmniOS