[PATCH 11/33] Populate AUXV

Janani Venkataraman
2014-03-20T09:41:01Z

Populate the auxillary vector using /proc/pid/auxv.

Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com>
Signed-off-by: Janani Venkataraman <jananive@linux.vnet.ibm.com>
---
src/elf.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)

diff --git a/src/elf.c b/src/elf.c
index 18bbeeb..b7fd6d0 100644
--- a/src/elf.c
+++ b/src/elf.c
@@ -26,12 +26,16 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
#include <sys/uio.h>
#include <sys/procfs.h>
#include <linux/elf.h>
#include "elf-compat.h"
#include "coredump.h"

+#define PAGESIZE getpagesize()
+
#define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y))

/* Appending the note to the list */
@@ -240,6 +244,70 @@ static int get_prpsinfo(int pid, struct core_proc *cp)
return add_note("CORE", NT_PRPSINFO, sizeof(prps), &prps, cp);
}

+/* Populate auxillary vector */
+static int get_auxv(int pid, struct core_proc *cp)
+{
+ unsigned char buff[PAGESIZE];
+ char filename[40];
+ int ret, fd, pages;
+ unsigned char *ptr, *auxv;
+ unsigned int auxv_size;
+
+ snprintf(filename, 40, "/proc/%d/auxv", pid);
+
+ fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ status = errno;
+ gencore_log("Failure while fetching auxv data from %s.\n",
+ filename);
+ return -1;
+ }
+
+ auxv = malloc(PAGESIZE);
+ if (!auxv) {
+ status = errno;
+ gencore_log("Could not allocate memory for the auxv_buffer.\n");
+ close(fd);
+ return -1;
+ }
+ /* Position to copy the auxv data */
+ ptr = auxv;
+ pages = 1;
+ /*
+ * We read the auxv data page by page and also we don't not
+ * know the size of auxv, hence we read till ret becomes
+ * lesser than PAGESIZE.
+ */
+ while ((ret = read(fd, buff, PAGESIZE)) > 0) {
+ memcpy(ptr, buff, ret);
+ if (ret < PAGESIZE) /* Finished reading */
+ break;
+ else {
+ /* We have more data to read */
+ pages++;
+ auxv = realloc(auxv, pages * PAGESIZE);
+ ptr = auxv + ((pages - 1) * PAGESIZE);
+ }
+ }
+ if (ret >= 0)
+ auxv_size = ((pages - 1) * PAGESIZE) + ret;
+ else {
+ status = errno;
+ gencore_log("Failure while fetching auxv data from %s.\n", filename);
+ close(fd);
+ free(auxv);
+ return -1;
+ }
+
+ /* Adding AUXV */
+ ret = add_note("CORE", NT_AUXV, auxv_size, auxv, cp);
+
+ close(fd);
+ free(auxv);
+
+ return ret;
+}
+
int do_elf_coredump(int pid, struct core_proc *cp)
{
int ret;
@@ -254,5 +322,10 @@ int do_elf_coredump(int pid, struct core_proc *cp)
if (ret)
return -1;

+ /* Get Auxillary Vector */
+ ret = get_auxv(pid, cp);
+ if (ret)
+ return -1;
+
return 0;
}